20160184
Lipid composition and diet inferences in abyssal macrourids of the eastern North Pacific
The lipid compositions of 2 abyssal macrourids, Coryphaenoides armatus and C. yaqui- nae, from the eastern North Pacific were examined and used to infer diet. The resulting fatty acid (FA) profiles are the first published for C. yaquinae and among the first for abyssal fishes. They indicated a greater proportion of polyunsaturated FAs and lower monounsaturated FAs than shallower living con- geners, suggestive of homeoviscous adaptations to great pressure. Cholesterol was the predominant sterol, which is frequently the case for exclusively car- nivorous species. Comparisons of macrourid FA pro- files were made to those of benthic prey and epipelagic carrion sources, including the Humboldt squid Dosidicus gigas captured in surface waters of the abyssal study site. The FA profiles of macrourid muscle were very similar to those of squid mantle muscle. The FA profiles of macrourid liver and swim- bladder were similar to benthic crustaceans, whole squid, squid digestive gland and the epipelagic fish Trachurus symmetricus. For both tissues, the FA pro- files of echinoderms were the most different. These comparisons suggest a strong link to carrion and ben- thic crustaceans and a weak one to echinoderms, the dominant megafauna at the study site and in most of the abyssal ocean. These results support previous stomach content and stable isotope analyses, reinforc- ing the hypothesis that there are closer food web ties between abyssal fishes and epipelagic nekton than to many abyssal benthic groups.
88922875
In situ studies on deep-sea demersal fishes using autonomous unmanned lander platforms
Techniques are described for research on deep-sea fishes using in situ lander platforms equipped with cameras for imaging fishes, sonars for tracking movements and other environmental monitoring sensors. Fishes are attracted to the vicinity of the platform by bait placed within view of the camera. Over most of the world's oceans at depths greater than 3000 m the dominant scavenging fish is the grenadier Coryphaenoides (Nematonurus) armatus arriving at bait within 15-150 min depending on local population abundance. Applying an inverse square law relationship scavenger abundance can be calculated from fish arrival times. These fish show evidence of optimal foraging, staying longer at the bait if food is sparse. Ingestible acoustic transmitters embedded in baits allow tracking of fish departing from the bait source. Average radial rate of movement in the abyss is 1.75 cm s -1 dispersing small food falls within a few hours. C. armatus in the north Pacific Ocean double their swimming speed in late summer associated with seasonal enrichment of the benthos with organic carbon. In situ techniques allow comparison of swimming performance of different species, allowing elucidation of mechanisms of niche separation in otherwise apparently similar fish. Autonomous lander platforms are proposed as an important adjunct to conventional research methods based on capture of dead specimens of fish from the wild.
85031196
Depth zonation and bathymetric trends of deep-sea megafaunal scavengers of the Hawaiian Islands
Abstract The deep sea has been shown to exhibit strong depth zonation in species composition and abundance. Examination of these patterns can offer ecological insight into how organisms adapt and respond to changing environmental parameters that co-occur with depth. Here we provide the first tropical study on bathymetric zonation and other depth-related trends (size, abundance, and species richness) spanning shelf to abyssal depths of scavenging megafauna. Baited time-lapse free-vehicle cameras were used to examine the deep-sea benthic and demersal scavenging communities of the Hawaiian Islands, an area for which the biology and ecology have remained poorly studied below 2000 m. Twenty-two deployments ranging in depth from 250 to 4783 m yielded 37 taxa attracted to bait, including the first known occurrence of the family Zoarcidae in the Hawaiian Islands. Cluster analysis of Bray–Curtis similarity of species peak abundance ( n max ) revealed four main faunal zones (250–500, 1000, 1500–3000, and ⩾4000 m) with significant separation (ANOSIM, global R =0.907, p =0.001) between designated depth groups. A major faunal break was identified at the 500–1000 m transition where species turnover was greatest, coinciding with the location of the local oxygen minimum zone. Dominance in species assemblage shifted from decapod crustaceans to teleosts moving from shallow to deeper faunal zones. Significant size differences in total length with depth were found for two of the four fish species examined. A logarithmic decline was observed in scavenger relative abundance with depth. Evidence of interaction between scavenging species was also noted between Synaphobranchus affinis and Neolithodes sp. (competition) and Histiobranchus sp. and aristeid shrimp (predation), suggesting that interactions between scavengers could influence indices of abundance generated from baited camera data.
140546602
Pelagic food of Coryphaenoides armatus, a deep benthic rattail☆
Abstract Stomach contents from 79 specimens of the macrourid Coryphaenoides armatus trawled at depths below 2600 m in Hudson Canyon fell into three major categories: benthic animals, pelagic animals, and items of terrestrial or neritic origin. Pelagic cephalopods and fishes, especially Chauliodus and Serrivomer spp., were important components of the diet, particularly of the larger fish, and it is suggested that C. armatus may move off the bottom into mid-depths to feed. The findings of vegetables, insect and bird remains, and strips of rubber and plastic in the stomachs indicate that this species is extremely generalized in its feeding habits. Its activities are important in transferring food energy from mid-depths over the deep-ocean floor, where rather large food items must be originally dispersed as finer particles.
85627009
Trophic ecology of deep-water fishes associated with the continental slope of the Eastern Norwegian Sea
Abstract In June 1995 and 1996 demersal fishes on the continental slope of the eastern Norwegian Sea were sampled to study distribution patterns and community structure. The diets of the more abundant slope species were characterised and linkages within the upper slope food web identified. Most of the smaller fishes fed on hyperbenthic crustaceans such as amphipods and mysids, while pelagic crustaceans and fish dominated the diets of larger fishes. Herring (Clupea harengus) and blue whiting (Micromesistius poutassou) were important prey items of Greenland halibut (Reinhardtius hippoglossoides), and were also eaten by Lycodes frigidus, Raja hyperborea, and roughhead grenadier (Macrounis berglax). At least for the latter three species this probably reflected scavenging. Few cases of predator-prey relationships between the typical slope fishes were found.
129170789
The feeding habits of slope dwelling macrourid fishes in the eastern North Pacific
Abstract The diet of slope dwelling macrourid fishes in the eastern North Pacific is poorly known. We collected several hundred stomach samples to investigate the feeding habits of Coryphaenoides acrolepis and Albatrossia pectoralis , the two dominant slope dwelling macrourids off the continental United States. Coryphaenoides acrolepis exhibited a pronounced ontogenetic shift in diet. Specimens 15 cm with scavenged food constituting approximately 20% of the weight of total prey and occurring in approximately 20% of fish 21–29 cm. Albatrossia pectoralis consumed primarily midwater fish and squid, and we believe that it feeds in the water column. There were significant differences between the diets of A. pectoralis and C. acrolepis suggesting some degree of niche separation between macrourid species on the continental slope of the eastern North Pacific. Both species are at the top of the food web on the upper continental slope and, because of their abundance, may exert significant pressures on their prey populations.
129155239
Long-term change in the megabenthos of the Porcupine Abyssal Plain (NE Atlantic)
A radical change in the abundance of invertebrate megafauna on the Porcupine Abyssal Plain is reported over a period of 10 years (1989–1999). Actiniarians, annelids, pycnogonids, tunicates, ophiuroids and holothurians increased significantly in abundance. However, there was no significant change in wet weight biomass. Two holothurian species, Amperima rosea and Ellipinion molle, increased in abundance by more than two orders of magnitude. Samples from the Porcupine Abyssal Plain over a longer period (1977–1999) show that prior to 1996 these holothurian species were always a minor component of the megafauna. From 1996 to 1999 A. rosea was abundant over a wide area of the Porcupine Abyssal Plain indicating that the phenomenon was not a localised event. Several dominant holothurian species show a distinct trend in decreasing body size over the study period. The changes in megafauna abundance may be related to environmental forcing (food supply) rather than to localised stochastic population variations. Inter-annual variability and long-term trends in organic matter supply to the seabed may be responsible for the observed changes in abundance, species dominance and size distributions.
29864283
Shifts in Deep-Sea Community Structure Linked to Climate and Food Supply
A major change in the community structure of the dominant epibenthic megafauna was observed at 4100 meters depth in the northeast Pacific and was synchronous to a major El Niño/La Niña event that occurred between 1997 and 1999. Photographic abundance estimates of epibenthic megafauna from 1989 to 2002 show that two taxa decreased in abundance after 1998 by 2 to 3 orders of magnitude, whereas several other species increased in abundance by 1 to 2 orders of magnitude. These faunal changes are correlated to climate fluctuations dominated by El Niño/La Niña. Megafauna even in remote marine areas appear to be affected by contemporary climatic fluctuations. Such faunal changes highlight the importance of an adequate temporal perspective in describing biodiversity, ecology, and anthropogenic impacts in deep-sea communities.
127542910
The Deep-Sea Benthic Fish Fauna of the Northeastern Pacific Ocean on Cascadia and Tufts Abyssal Plains and Adjoining Continental Slopes
AbstractThe faunal composition of deep-sea fishes is described from 579 beam and otter trawl collections from the continental slope and abyssal plains off Oregon, at depths from 400 to 5,180 m. Ninety of the 104 species known to inhabit depths greater than 400 m in this area of the northeastern Pacific were captured. Sixty-one species were found on the continental slope, 28 on Cascadia Abyssal Plain, nine on eastern Tufts Abyssal Plain, and two on western Tufts Plain.Families represented by the most species were Scorpaenidae, Liparididae, and Zoarcidae on the slope, and Liparididae, Zoarcidae, and Macrouridae on the abyssal plains. Scorpaenids were numerically dominant on the upper slope, and macrourids on the mid-lower slope and abyssal plains. The macrourid Coryphaenoides armatus was caught at all abyssal stations and was consistently the most abundant fish at depths greater than 2,500 m. Coryphaenoides filifer and C. leptolepis were consistently the second and third most numerous species on Cascadia.Th...
54841857
Fish faunal and habitat analyses using trawls, camera sleds and submersibles in benthic deep-sea hab
Abstract Beam trawl, camera sled and submersible data from 2 000–3 300 m off central California produced similar fish faunal composition, but different density estimates. All species caught in trawls were observed in camera-sled and submersible observations. However, some rare species that were observed were not caught in trawls. The fish fauna was dominated by the families Macrouridae, Zoarcidae, Moridae, and Rajidae. Fishes both trawled and observed were the macrourids Coryphaenoides armatus, C. filifer and C. leptolepis; the zoarcids Bothrocara spp., Pachycara lepinium and Lycenchelys spp.; the morid Antimora microlepis; the rajid Bathyraja trachura, the ophidiid Spectrunculus grandis, and the liparidid Careproctus ovigerum. One unidentified liparidid (Paraliparis sp.) and two unidentified Lycenchelys spp. were trawled and may have been seen but also could not be identified to species from photographs. Observed only in photographs were the liparidids Paraliparis rosaceus and Careproctus melanurus, synodontid Bathysaurus mollis, and notocanthid Notacanthus chemnitzii. These three techniques differed in their ability to provide specimens for accurate identification, counts, and later life history (feeding habit, age and growth, and reproduction) studies, and to provide information on dispersion, habitat utilization, behavior and interactions. Accurate density estimates were undoubtedly hampered by trawl and camera sled avoidance, escape, and uncertainties concerning the area trawled. Camera sleds produced higher (and perhaps better) estimates of density. Submersible observations from the DSV Alvin produced a similar species list but little additional, quantitative information. Both visual techniques allowed habitat characterization, but no strong faunal associations with habitat types were observed.
128809620
Long time-series monitoring of an abyssal site in the NE Pacific: an introduction
Deep-Sea Research II 45 (1998) 573—586 Long time-series monitoring of an abyssal site in the NE Pacific: an introduction K.L. Smith, Jr.!,*, E.R.M. Druffel ! Marine Biology Research Division 0202, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202, USA Department of Earth System Science, University of California, Irvine, Irvine, CA 92697, USA Received 20 October 1997; in revised form 31 October 1997; accepted 4 November 1997 1. Introduction Abyssal regions of the world ocean cover more than 50% of the Earth’s surface (Gage and Tyler, 1991) but the biogeochemical processes in the sediments and deep water column of this vast expanse of our globe are poorly understood. The cycling of material through these deep-sea regions is intimately linked to the organic matter produced in the euphotic zone. The material sinks as particulate matter, undergoing various physical and biochemical transformations in the water column before reach- ing the seafloor. Temporal variability of plankton production in the upper ocean is well documented. The fraction of this production that escapes the euphotic zone as particulate organic matter sinking into the deep sea also exhibits temporal variability, reflecting the changes in surface water production. Independent long time-series measurements of particulate organic matter fluxes to abyssal depths (e.g. Deuser et al., 1981; Honjo, 1982; Deuser, 1986; Haake et al., 1993) and time-lapse photographic records of phytodetrital pulses reaching the sea floor (e.g. Billett et al., 1983; Lampitt, 1985; Rice et al., 1986), although taken in widely separated areas of the deep ocean, have been invaluable for predicting events in other regions. However, the cycling of organic matter in the deep ocean has been difficult to evaluate because synoptic measurements on sufficiently long time scales are rare. The lack of long time-series measurements to examine concurrently the input of a pelagi- cally derived food supply and its impact on benthic boundary layer (BBL) processes *Corresponding author. Fax: 001 619 534 7313; e-mail: ksmith@ucsd.edu. 0967-0645/98/$19.00 ( 1998 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 7 - 0 6 4 5 ( 9 7 ) 0 0 0 9 4 - 5
15800062
Bypassing the abyssal benthic food web: Macrourid diet in the eastern North Pacific inferred from stomach content and stable isotopes analyses
Deep-sea fishes prey on benthic fauna and scavenge on the carcasses of surface-living animals. Few studies have addressed the relative importance of each trophic pathway. Recent documentation of inter-decadal fluctuations in macrourid densities in the abyssal Pacific, related to changing food supplies, hastens the need for information. We conducted stomach content and stable isotope analyses of two abyssal macrourids, carrion sources, and benthic prey, collected concurrently at 4100 m off California. Squid and fishes were the most frequent prey for Coryphaenoides armatus, with small crustaceans numerous in the diet of small specimens. The diet of Coryphaenoides yaquinae included more benthic prey such as crustaceans, polychaetes, and the holothuroid Protankyra brychia. Carrion was present in both species and it was 69% of the mass of food of large C. armatus. Carrion d 15 N values were comparable to those in abyssal deposit feeders, but carrion was relatively enriched in 13 C, giving it a unique isotopic signature compared to benthic prey sources. The highest d 13 C and d 15 N values were observed in benthic shrimps and large polychaetes. The two macrourids had intermediate values, with C. armatus having slightly but significantly lower d15N relative to C. yaquinae. Results of isotope mass balance suggest that carrion was the most important prey resource for both species but to a lesser extent in C. yaquinae. These two species bypass the conventional phytodetritus-based abyssal food web for much of their nutrition. Their population dynamics may be tied more closely to fluctuations in epipelagic nekton populations through fishing effects and direct climatic forcing on top trophic levels.
83892227
LIPIDS AND TROPHODYNAMICS OF ANTARCTIC ZOOPLANKTON
Abstract Zooplankton were collected by trawl from the Elephant Island region of the Antarctic Peninsula and from East Antarctica near 63–65°S and 139–150°W. Most zooplankton had low percentages of wax esters (0–8%, as percent of total lipid). High triacylglycerol levels were found in the hyperiid amphipod Themisto gaudichaudii (68%, as percent of total lipid), the krill (Euphausiacea) Euphausia tricantha (44–54% triacylglycerol) and Euphausia frigida (27% triacylglycerol) and the scyphomedusan Periphylla periphylla ( 42–48% triacylglycerol). Polyunsaturated fatty acids (PUFA) comprised 23–60% of the total fatty acids, with the omega-3 fatty acids eicosapentaenoic acid [20:5(n-3)] and docosahexaenoic acid [22:6(n-3)] being most abundant. P. periphylla was an exception with 12–19% docosapentaenoic acid [22:5 (n-3)] being the major PUFA. The major euphausiid sterols included cholesterol (75–92%, as percent of total sterols) and desmosterol (6–22%). The major sterols of other zooplankton were more diverse and included trans -dehydrocholesterol, 24-methylenecholesterol, brassicasterol and 24-nordehydrocholesterol. The benthic ascidian, Distaplia cylindrica , had 45% stanols, as percent of total sterols, whereas the pelagic ascidian Salpa thompsonii had only 8–11% stanols. Lipid, fatty acid and sterol data are used to examine trophodynamic interactions and provide an ability to distinguish herbivorous and carnivorous diets and determine survival and reproductive strategies.
25788844
Fatty acid trophic markers in the pelagic marine environment.
Fatty acids have been used as qualitative markers to trace or confirm predator-prey relationships in the marine environment for more than thirty years. More recently, they have also been used to identify key processes impacting the dynamics of some of the world's major ecosystems. The fatty acid trophic marker (FATM) concept is based on the observation that marine primary producers lay down certain fatty acid patterns that may be transferred conservatively to, and hence can be recognized in, primary consumers. To identify these fatty acid patterns the literature was surveyed and a partial least squares (PLS) regression analysis of the data was performed, validating the specificity of particular microalgal FATM. Microalgal group specific FATM have been traced in various primary consumers, particularly in herbivorous calanoid copepods, which accumulate large lipid reserves, and which dominate the zooplankton biomass in high latitude ecosystems. At higher trophic levels these markers of herbivory are obscured as the degree of carnivory increases, and as the fatty acids originate from a variety of dietary sources. Such differences are highlighted in a PLS regression analysis of fatty acid and fatty alcohol compositional data (the components of wax esters accumulated by many marine organisms) of key Arctic and Antarctic herbivorous, omnivorous and carnivorous copepod species. The analysis emphasizes how calanoid copepods separate from other copepods not only by their content of microalgal group specific FATM, but also by their large content of long-chain monounsaturated fatty acids and alcohols. These monounsaturates have been used to trace and resolve food web relationships in, for example, hyperiid amphipods, euphausiids and fish, which may consume large numbers of calanoid copepods. Results like these are extremely valuable for enabling the discrimination of specific prey species utilized by higher trophic level omnivores and carnivores without the employment of invasive techniques, and thereby for identifying the sources of energetic reserves. A conceptual model of the spatial and temporal dominance of group-specific primary producers, and hence the basic fatty acid patterns available to higher trophic levels is presented. The model is based on stratification, which acts on phytoplankton group dominance through the availability of light and nutrients. It predicts the seasonal and ecosystem specific contribution of diatom and flagellate/microbial loop FATM to food webs as a function of water column stability. Future prospects for the application of FATM in resolving dynamic ecosystem processes are assessed.
85137502
Fatty acid and lipid composition of 10 species of microalgae used in mariculture
Abstract Total fatty-acid composition, lipid classes, Chl a contents and cell volumes of 10 species of microalgae commonly used in mariculture were examined. The microalgae were grown under defined conditions and harvested during log phase. Significant concentrations of the polyunsaturated fatty acid 20:5(n-3) (eicosapentaenoic acid) were present in each of the four diatoms Chaetoceros calcitrans, Chaetocerosgracilis, Skeletonema costatum and Thalassiosira pseudonana (4.6–11.1% of the total fatty acids), the cryptomonad Chroomonas salina (10.9, 11.9%) and the prymnesiophyte Pavlova lutheri (19.7%). Very small amounts were found in another prymnesiophyte, Isochrysis sp., and the green algae Nannochloris atomus and Tetraselmis suecica but none was detected in the green alga Dunaliella tertiolecta . In contrast, high concentrations of 22:6(n-3) (docosahexaenoic acid) were present only in the two prymnesiophyte algae and Chroomonas salina . Chl a and total fatty-acid contents were not related to cell volume. Fatty acids were four to six times more abundant than Chl a in most species. Relative concentrations of intact lipids were determined for each species using latroscan thin-layer chromatography-fiame-ionisation detection. Polar lipids predominated in all species but triacyglycerols were abundant only in Chaetoceros gracilis, Isochrysis sp. and Chroomonas sp. Free fatty acids were particularly abundant in the two Chaetoceros species. The importance of these data for determining the nutritional value of the microalgae as food for animals in mariculture is discussed.
84942610
A review of sterol markers for marine and terrigenous organic matter
Abstract A review of literature on the occurrence of 4-desmethyl sterols in unicellular algae indicates that few sterols are sufficiently restricted in distribution to be considered unambiguous markers for specific algal groups. Almost all of the 4-desmethyl sterols found in higher plants occur in marine algae, sometimes as major constituents, so sterol distributions do not always allow to distinguish between marine or terrigenous organic matter. Some of the problems associated with the use of sterols as markers for specific sources are highlighted by comparison of the sterol distribution in selected marine sediments and seawater samples. Although each sediment represents a very different depositional environment the sterol distributions are surprisingly similar. The sterol distributions in a saline Antarctic lake and samples of particulate matter from oligotrophic waters off the east Australian coast show that marine phytoplankton biosynthesize a wide range of sterols, including large amounts of 24-ethylcholest-5-en-3β-ol which is often used as a marker for terrigenous organic matter. Similar distributions occur in marine sediments from the upwelling area off Peru and in temperate intertidal sediments despite large differences in algal productivity between the two areas. In deeper sediments, most of the sterols are not derived from phytoplankton but from higher plants. These data indicate that inferences drawn from sterol distributions regarding sources of organic matter must be made with caution and should be supported using other lipid data. It further follows that in ancient sediments and crude oils a high proportion of C 29 steranes need not indicate that most of the organic matter was derived from vascular plants.
55003844
Predation on myctophids by the squid Moroteuthis ingens around Macquarie and Heard Islands: Stomach contents and fatty acid analyses
The diet of the sub-Antarctic onychoteuthid squid Moroteuthis ingens was assessed using stomach contents analyses and fatty acids as dietary tracers. The contents of 54 stomachs (50 from squid collected near Macquarie Island and 4 from squid collected near Heard Island) were examined visually, and prey remains were identified to species level where possible. Myctophid fish were the most common prey item in the stomach contents of M. ingens and were identified in 59% of stomachs. In total, teleost fish remains were found in 96% of stomachs. The lipid class and fatty acid profiles of the digestive gland and mantle tissue were analysed for 5 to 6 squid from each area, in addition to 4 stomach fluid samples taken from Heard Island animals. Mantle tissue was low in lipid, and contained high concentrations of phospholipids and polyunsaturated fatty acids. Digestive gland tissue had a high lipid content, with a mean value of 26.8 ± 12.9% wet mass in Macquarie Island squid and 41.7 ± 8.5% wet mass in Heard Island squid, and was rich in triacylglycerol (TAG) and monounsaturated fatty acids (MUFA). Stomach fluid generally contained high concentrations of TAG, although 1 sample was high in wax ester. Stomach fluid was also characterised by high MUFA con- centrations. The digestive gland of M. ingens grouped with the fatty acid profile of stomach fluid and some myctophid species in cluster analysis and multidimensional scaling, and appears to be a source of fatty acid dietary tracers. Thus the fatty acid profile of the digestive gland supports findings from stomach contents analyses that myctophids, particularly TAG-rich species, are an important prey group of M. ingens at Macquarie and Heard Islands. This combination of techniques has a potential to increase our knowledge of the feeding ecology of squids in the Southern Ocean.
84584496
Trophic position of deep-sea fish - assessment through fatty acid and stable isotope analyses
To investigate the trophic ecology of two of the dominant families of deep-sea fish (Macrouridae and Moridae) fatty acid and stable isotope analyses were applied to liver and muscle samples of five abundant species from the NE Atlantic. In conjunction with stomach content data these methods made it possible to identify differences in feeding strategies between the five study species as well as variation in feeding in relation to increasing depth and body size. Biomarkers identified strong similarities between Coryphaenoides armatus and Antimora rostrata though differences were found associating C. armatus more with the benthic food web whereas A. rostrata showed stronger links to the pelagic food web. While Lepidion eques was classified as a species linking benthic and benthopelagic food webs, both fatty acid and stable isotope data suggested that Coryphaenoides guentheri fed on an exclusively benthic diet. Coryphaenoides rupestris on the other hand were largely dependent on a copepod-based food web. Ontogenetic changes in feeding were found for both A. rostrata and C. armatus with the indication of a switch from active predation to scavenging occurring with increasing body size. Biomarkers also reflected the seasonal influx from the photic zone though changes were species-specific and probably reflected the variation in prey availability and abundance in response to these inputs. Our findings have thus demonstrated that the combined use of these biomarkers can elucidate trophic specialisations in situations where conventional methods alone previously provided insufficient data.
54930822
Occurrence of diacyl glyceryl ethers in liver lipids of gonatid squid Gonatopsis borealis.
The lipid class compositions of the livers of two different size groups and of the mantles of gonatid squid Gonatopsis borealis from the northwest Pacific Ocean were investigated. In this species, the liver had a remarkably high level of lipids (26.5%), which were characterized by diacyl glyceryl ethers (16.3%) and triglycerides (33.0%). The liver lipids of the small-size squids (mantle length: 13.4 cm) contained relatively higher levels of diacyl glyceryl ethers (27.0%) than those (10.3%) of the large ones (22.5 cm). On the contrary, the mantle contained only trace amounts of these lipids but were high in phospholipids (84.0%). In the livers of the two different size groups and the mantle of this species, glyceryl ethers originating from diacyl glyceryl ethers were very similar in composition; the most abundant component was chimyl alcohol (38.6 to 45.9% and 66.2%, respectively). Among the tissues examined, differences were found in the percentage of component fatty acids of the total lipids.
84320593
Fat content and fatty acid composition of forage fish and invertebrates in Prince William Sound, Alaska: factors contributing to among and within species variability
We determined the fat content and fatty acid composition of 26 species of fish and inver- tebrates (n = 1153) that are primary forage species of piscivorous seabirds and marine mammals in Prince William Sound (PWS), Alaska. Flatfish, shrimps and octopus had the lowest average fat con- tents (~1.0%), although some cods, as well as juvenile walleye pollock Theragra chalcogramma, Pacific herring Clupea harengus pallasi and pink salmon Oncorhynchus gorbuscha also ranged as low as 0.5 to 0.7% fat. The highest fat contents were found in eulachon Thaleichthys pacificus (25%), adult herring (21%) and the squid Berrytheuthis magister (5 to 13%). Within species, fat content var- ied mostly with season, but also with size. Fatty acid signatures generally distinguished forage spe- cies, with up to 95% of individuals correctly classified using either discriminant or classification and regression tree (CART) analyses. Discriminant plots provided insight into the relationships between fatty acid signatures of different species. Species with similar life histories and diets clustered closer together, while those with the greatest differences in ecology differed most in their fatty acid pat- terns. Within some species, changes in fatty acid signatures were apparent with increasing size and were consistent with known dietary shifts reported from stomach contents analyses. Furthermore, fatty acid signatures of Age 0 (yr) pollock and herring in PWS were consistent with previous stomach contents analysis that indicated annual differences in the timing of dietary changes from eating zoo- plankton to piscivory. Overall, when size/age classes were taken into account, species classification using fatty acid signatures was improved. Our findings have important implications for evaluating diets and food web interactions of fish stocks, as well as at higher trophic levels. Despite individual variation within species, our results indicate that fatty acid signatures accurately characterize forage species in this ecosystem, and consequently can be used to study and perhaps estimate the species composition of diets of their predators.
84713371
LIPID DAMAGE DURING FROZEN STORAGE OF WHOLE JACK MACKEREL (TRACHURUS SYMMETRICUS MURPHYI)
The damage on the lipid fraction of whole jack mackerel (Trachurus symmetricus murphyi, Carangidae) during 120 days of frozen storage was studied. The chemical composition was determined through proximate analysis. Lipid quality deterioration was evaluated by measuring free fatty acids, peroxide values, conjugated dienes and p-anisidine values. Also, the total volatile base-nitrogen value was determined to check the bacterial activity during frozen storage. The results showed that jack mackerel is a medium-fat fish species with 74-78% moisture, 3-5% fat (crude) with 20-27% polyunsaturated fatty acids (PUFA). The lipid hydrolysis was the major damage during frozen storage, with a correlation coefficient of 0.96 after 75 days of storage. The normal oxidative rancidity (primary and secondary products) present in fillets of different species was not observed in the whole fish. The autolytic changes were predominant, because bacterial activity was low during the entire storage time.
85426451
Depth related trends in proximate composition of demersal fishes in the eastern North Pacific
Abstract The proximate chemistry of the white muscle and liver of 18 species of demersal fish from the eastern North Pacific was studied to determine trends with depth, locomotory mode and buoyancy mechanism, foraging strategy and to elucidate energetic strategies. Data for 24 species from shallow water were taken from the literature and included for analysis of muscle water content. Benthopelagic species, primarily gadiforms, have significantly larger lipid-rich livers than benthic species. The benthopelagic species may use this lipid to add buoyancy, but it is also used as energy storage. Buoyancy mechanism was directly related to proximate composition. Fishes using gasbladders had normal muscle composition. The two species of benthopelagic fishes without gasbladders have either very high muscle lipid content ( Anoplopoma fimbria ) or gelatinous muscle ( Alepocephalus tenobrosus ) to aid in achieving neutral buoyancy. The macrourid, Albatrossia pectoralis , has a very small gasbladder and also has gelatinous muscle. Both of these benthopelagic fishes with gelatinous muscle feed on pelagic organisms. Gelatinous muscle was also found in two flatfishes that inhabit the oxygen minimum zone. For these fishes, high water content may serve to lower metabolic costs while maintaining large body size. Scavengers such as Coryphaenoides armatus and Coryphaenoides acrolepis have lipid rich livers and others such as A. fimbria and Pachycara sp. have high and variable muscle lipid content. Thus foraging mode also acts to influence proximate composition. Several depth-related trends in proximate composition were found. White muscle water content increased significantly with depth, and all four gelatinous species occurred at bathyal depths. This adds evidence in support of the hypothesis that decreasing light levels shorten reactive distances and relax the selective pressure for high locomotory capacity. In addition significant declines in liver protein content were observed, suggesting that the rates of metabolism in this organ also decline with depth. There was little evidence for food availability affecting proximate composition. There were no significant changes in either muscle or liver lipid or caloric density with depth. Total lipid stores actually increased significantly, but they were driven primarily by the abyssal scavenger C. armatus suggesting that foraging strategy rather than depth may be the most important factor determining total lipid stores.
7311923
A rapid method of total lipid extraction and purification.
Lipid decomposition studies in frozen fish have led to the development of a simple and rapid method for the extraction and purification of lipids from biological materials. The entire procedure can be carried out in approximately 10 minutes; it is efficient, reproducible, and free from deleterious manipulations. The wet tissue is homogenized with a mixture of chloroform and methanol in such proportions that a miscible system is formed with the water in the tissue. Dilution with chloroform and water separates the homogenate into two layers, the chloroform layer containing all the lipids and the methanolic layer containing all the non-lipids. A purified lipid extract is obtained merely by isolating the chloroform layer. The method has been applied to fish muscle and may easily be adapted to use with other tissues.
85184597
Thin-layer chromatography — flame ionization detection and the quantitation of marine neutral lipids and phospholipids
Abstract A method is described whereby a complete analysis of individual neutral lipid and phospholipid classes in marine animal total lipid can be achieved using an latroscan TLC-FID analyser. The method involves separate analyses of two samples of total lipid in solvents designed to separate neutral and polar lipid classes, together with calibration by a composite standard similar in composition to the sample under analysis. The method does not depend on the degree of unsaturation of the fatty acids present, is rapid and compares well in accuracy with conventional combined gravimetric, colouritnetric, and densitometric procedures.
1893689
Vertical stratification of fatty acids in the blubber of southern elephant seals (Mirounga leonina): implications for diet analysis.
Fatty acid signature analysis (FASA) is a powerful ecological tool that uses essential fatty acids (FA) from the tissues of animals to indicate aspects of diet. However, the presence of vertical stratification in FA distribution throughout blubber complicates the application of FASA to marine mammals. Blubber biopsy samples were collected from adult female southern elephant seals (Mirounga leonina) from Macquarie Island (n=11), and blubber cores were divided into inner and outer sections to determine the degree to which the blubber layer was stratified in FA composition, we found 19 FA from both blubber layers in greater than trace amounts (>0.5%). The inner and outer blubber layers could be separated using principal components analysis based on the relative proportion of FA in each layer. Dietary polyunsaturated fatty acids (PUFA) were also observed in significantly higher proportions in the inner blubber layer. Due to the degree of FA stratification in southern elephant seals, we concur with other marine mammal studies that sampling only the outer blubber layer will result in a loss of recently accumulated information regarding diet structure (as indicated by 'surplus' PUFA from the diet). This finding suggests that differential mobilization/deposition of certain FA may result in a modified signature from prey to predator. Thus, sampling animals to recover the inner blubber layer is important for studies attempting to describe aspects of marine mammal diet. This can be achieved in animals such as pinnipeds where the whole blubber layer can be readily sampled.
73652675
Temporal variations in the diet of the squid Moroteuthis ingens at Macquarie Island: stomach contents and fatty acid analyses
The onychoteuthid squid Moroteuthis ingens was collected as by-catch from a commercial trawl fishery in the vicinity of Macquarie Island, within the Pacific sector of the Southern Ocean. Squid were collected during 3 austral summers and 1 austral winter between January 1995 and June 2000. Stomach contents and fatty acid profiles of both mantle and digestive gland tissues were used to determine if the diet of M. ingens was subject to temporal variations in this region. Discriminant analysis (DA) of stomach contents data and digestive gland fatty acid data indicated that the diet varied significantly on an interannual basis, most likely due to an increase in the consumption of the myctophid Gymnoscopelus nicholsi during the summer of 1999 relative to the summers of 1995 and 2000. Comparisons with oceanographic data reveal that the summer of 1999 was a period of warmer sea-surface temperatures and reduced primary production compared to the summers of 1995 and 2000. Fluctuations in oceanographic conditions may have underpinned variations in the availability of prey during the study period. DA of digestive gland fatty acid data also indicated that the diet varied significantly between the summer and winter of 2000. Stomach contents data indicate that the myctophid Electrona carlsbergi replaced Krefftichthys anderssoni as a key prey species for M. ingens during the winter period, as has been observed for other marine predators in the sub-Antarctic Southern Ocean. A comparison of methods reveals that, while fatty acid analyses greatly aid the interpretation of stomach contents data, both techniques are subject to limitations and are best used in combination.
128764393
Distribution and abundance of epibenthic megafauna at a long time-series station in the abyssal northeast Pacific
Abstract Abundance and dispersion of epibenthic megafauna were examined at an abyssal site (4100 m depth) in the northeast Pacific (Sta. M, 34°50'N, 123°00'W). Photogrammetric techniques and line-transect theory were used to analyze photographs from nine towed camera-sled transects made on six cruises between June 1990 and October 1991. The megafaunal assemblage was dominated numerically by the tube-dwelling polychaete Paradiopatra sp. and echinoderms, representing 26–48% and 24–41 % of the total, respectively. Megafaunal densities were remarkably similar among the nine transects, ranging from 26,594 to 39,913 individuals 10 −4 m −2 . While the overall assemblages in the nine transects were ⩽80% similar, based on pairwise comparisons, the relative contribution of each faunal category varied significantly between transects; densities of individual species from pairs of synoptic transects were significantly different ( p
7744946
Abundance and size distribution dynamics of abyssal epibenthic megafauna in the northeast Pacific.
The importance of interannual variation in deep-sea abundances is now becoming recognized. There is, however, relatively little known about what processes dominate the observed fluctuations. The abundance and size distribution of the megabenthos have been examined here using a towed camera system at a deep-sea station in the northeast Pacific (Station M) from 1989 to 2004. This 16-year study included 52 roughly seasonal transects averaging 1.2 km in length with over 35600 photographic frames analyzed. Mobile epibenthic megafauna at 4100 m depth have exhibited interannual scale changes in abundance from one to three orders of magnitude. Increases in abundance have now been significantly linked to decreases in mean body size, suggesting that accruals in abundance probably result from the recruitment of young individuals. Examinations of size-frequency histograms indicate several possible recruitment events. Shifts in size-frequency distributions were also used to make basic estimations of individual growth rates from 1 to 6 mm/month, depending on the taxon. Regional intensification in reproduction followed by recruitment within the study area could explain the majority of observed accruals in abundance. Although some adult migration is certainly probable in accounting for local variation in abundances, the slow movements of benthic life stages restrict regional migrations for most taxa. Negative competitive interactions and survivorship may explain the precipitous declines of some taxa. This and other studies have shown that abundances from protozoans to large benthic invertebrates and fishes all have undergone significant fluctuations in abundance at Station M over periods of weeks to years.
84352069
A seasonal analysis of the nutritional condition of deep‐sea macrourid fishes in the north‐east Pacific
Of three common macrourids Coryphaenoides armatus and Coryphaenoides yaquinae were collected from 1995 to 1998 at an abyssal station, c. 220 km west of Point Conception, California in the north-east Pacific (4100 m depth). Coryphaenoides acrolepis was collected from 1997 to 1998 in the San Diego Trough (1200 m depth). Energy storage in all three species was primarily in the liver, which was up to 56% lipid (wet mass) and up to 96% triglyceride. No seasonal variation in nutritional condition was found for C. armatus or C. yaquinae. There was, however, a significant increase in muscle water content and liver lipid content and a significant decline in muscle lactate dehydrogenase activity for C. armatus between 1996 and 1998. Potential mechanisms for these interannual shifts are proposed. No seasonal variation in parameters was found for C. acrolepis but a small seasonal periodicity in feeding activity may have existed. The seasonal deposition of phytodetritus in the deep sea is of little or no consequence to these fishes.
84415078
Amount of Squalene and Fatty Acid Composition of Triacylglycerols and Phospholipids in Flesh and Liver Lipids of Some Deep-sea Teleost Fish, Morid Cods and Whiptails
Examination was made of the amounts of squalene and fatty acid compositions of triacylglycerols (TG) and phospholipids (PL) in the flesh and liver lipids of five species of deep-sea teleost fish: the Pacific flatnose Antimora microlepis and the black mora Halargyreus johnsonii of morid cods and the roughscale rattail Coryphaenoides acrolepis, the pop-eye grenadier C. cinereus and the pectoral rattail C. pectoralis of whiptails. Liver specimens of these deep-sea teleost fish contained copious amounts of lipids (19.5-65.1%) which were composed almost entirely of TG (72.6-95.9%). Flesh samples contained small amounts of lipids (0.3-0.5%) with lower TG (0.9-1.4%) and higher PL (53.8-76.0%) content. In the livers and flesh, unsaponifiable matter from the neutral lipids comprised squalene (42.4-57.7% and 3.7-10.3%) and sterols (22.8-51.0% and 84.0-95.3%), respectively, and the squalene content of liver lipids corresponded to 0.57-1.76%. Component fatty acids in TG from liver lipids were characteristically rich in monoenes (59.5-73.0%) with 22:1n-11 (15.7-24.1%), 18:1n-9 (11.2-16.6%) and 20:1n-11 (8.7-10.9%) acids. Nevertheless, component fatty acids in PL from flesh lipids were rich in polyenes (37.6-44.2%) with 22:6n-3 (23.1-28.4%) and 20:5n-3 (8.7-8.8%) acids.
84942776
Energy budgets and feeding rates of Coryphaenoidesacrolepis and C. armatus
Abstract. This study develops energy budgets and estimates feeding rates for two macrourid fishes, Coryphaenoidesacrolepis, dominant in the bathyal eastern North Pacific, and the abyssal cosmopolitan species, Coryphaenoidesarmatus. Daily energy expenditure by C. acrolepis was nearly twice that of C. armatus. C. acrolepis allocated nearly equal amounts of energy to metabolism and growth. Once sexual maturity was reached reproduction became the dominant energetic cost. Either these costs are necessary to retain adequate numbers of eggs and larvae on the continental slopes, or this fish does not reproduce on an annual basis and the calculated costs are an overestimate. C. armatus allocated relatively more energy to metabolism than growth. It may be semelparous, and this strategy would be of great energetic savings in its food-poor but stable environment. Individual daily ration for C. acrolepis decreased from 0.31% to 0.07% of body weight (BW) and for C. armatus from 0.12% to 0.02% BW with increasing fish length. These rates are substantially lower than those for fishes living in cold waters on the continental shelves. The population feeding rates for C. acrolepis ranged from 0.8 to 15 kg km–2 day–1 and for C. armatus from 5 to 2,800 g km–2 day–1. The scavenging behaviour of C. acrolepis was used to investigate the role of carrion as a food supply to the deep-sea benthos. It was estimated that the carrion eaten by C. acrolepis is equivalent to 0.04 mg C m–2 day–1 or only 0.2–0.4% of the average small particulate flux. Carrion consumption is important for scavengers like C. acrolepis, but it is not an important component of the carbon flux into the deep-sea benthic environment.
24738387
Lipid, sterols and fatty acid composition of abyssal holothurians and ophiuroids from the North-East Pacific Ocean: food web implications.
The lipid, fatty acid (FA), and sterol composition of two ophiuroids and four holothurians from the abyssal eastern North Pacific were analysed to assess their feeding habits and to ascertain their composition for use in a larger study to examine food web dynamics and trophic ecology. Holothurians were rich in phytosterols and algal derived FA such as docosahexaenoic acid and eicosapentaenoic suggesting tight trophic coupling to phytodetritus. Large proportions of stanols were found, probably a result of enteric bacteria but they may come from sterol metabolism in the holothurians themselves. Oneirophanta mutabilis was distinct with much higher levels of stanols and bacterially derived FA suggesting specific selection of bacteria rich detrital particles or the activity of enteric and integumental bacteria. The ophiuroids sterol and FA compositions differed greatly from the holothurians and reflected consumption of animal material in addition to phytodetritus. Large proportions of energy storage lipids suggested a sporadic food supply. Several unusual fatty acids were found in these abyssal echinoderms. Tetracosahexaenoic acid, 24:6omega3, in ophiuroids and 23:1 in holothurians may be good biomarkers for food web studies. We report the first occurrence of alphaOH 24:1 in holothurians with none detected in ophiuroids. Its function is presently unknown.
86163307
Lipid, sterols and fatty acids of abyssal polychaetes, crustaceans, and a cnidarian from the northeast Pacific Ocean: food web implications
The lipid, sterol, and fatty acid compositions of the abyssal anemone Bathyphellia aus- tralis, the 3 polychaetes Laetmonice sp., Paradiopatra sp. and Travisia sp., 3 crustaceans (Munidopsis sp. and 2 lysianassid amphipods), and an unidentified caridean shrimp were determined from a site in the northeast Pacific Ocean. Lipid composition was dominated by phospholipids in most species. However, energy storage lipids (triacylglycerols and wax esters) contributed >50% to the total lipids in the lysianassid amphipods and the unidentified caridean shrimp, and lipids made up 19 and 45% of amphipod and 14% of shrimp dry mass, suggesting sporadic feeding and the need for energy stor- age. The dominant sterol was cholesterol. The presence of phytosterols in the anemone, the poly- chaetes and Munidopsis sp. suggested consumption of phytodetritus, but none of the specimens had levels suggesting that phytodetritus was their main food resource. The levels of essential photo- synthetically derived polyunsaturated fatty acids (PUFA) corroborated the sterol results. The ratio of 18:1ω9/18:1ω7 further suggested carnivory as the predominant mode of foraging in the abyssal ani- mals, although to varying degrees. Some distinct differences in the fatty acid (FA) composition of these animals allowed for their separation, confirming that FA profiles will be useful in future bio- marker approaches to deep-sea food web studies.
5623903
Composition of lipid foams from swim bladders of two deep ocean fish species.
Lipid-containing deposits within the swim bladders of Coryphaenoides acrolepis and Antimora rostrata were investigated. Lipid analysis of this material, which was quite uniform from the two species, yielded the following data: neutral lipids, 36.0-41.7%; phospholipids, 53.6-56.7%; and glycolipids, 4.3-8.9%. Cholesterol (mainly in the free form) constituted 60.4%-77.8% of the neutral lipids. Sphingomyelin and phosphatidylcholine were the principal phospholipids, with sphingomyelin highest in the material from C. acrolepis and phosphatidylcholine predominant in that from A. rostrata. The overall pattern of lipids shows a resemblance to that of plasma membrane, particularly in the relatively high levels of free cholesterol, sphingomyelin, and phosphatidylserine. The lipid-to-protein ratio of the material is approximately 1.5-2 to 1. The lipids of the fine inner lining (tunica interna) of the swim bladder from a shallow water fish, the kelp bass (Paralabrax clathratus), had essentially the same composition as the much more abundant swim bladder material from the deep ocean fishes.
35668181
The membranous lining of the swimbladder in deep sea fishes. I. Morphology and chemical composition.
Abstract 1. 1. Cholesterol-rich swimbladder foams from Coryphaenoides (cf. fernandezianus ) and Parabassogigas sp. collected from 3400 to 4575 m depth appear as sheets of layered membranes having typical bilayers. 2. 2. Sphingomyelin was the major phospholipid in Parabassogigas swimbladder foam (48.7 and 63.0 per cent) whereas phosphatidylcholine (39.1–44.8 per cent) was the major phospholipid in Coryphaenoides . 3. 3. Although percentages of both cholesterol and phospholipids were lower in Parabassogigas than in Coryphaenoides , the ratio of cholesterol to phospholipid was close to one to one in both fish. 4. 4. Total fatty acid unsaturation in the swimbladder foams was high (71.4–80.5 per cent) despite the presence of hyperbaric oxygen.
85084125
Lipid and fatty acid composition of the mantle and digestive gland of four Southern Ocean squid species: implications for food-web studies
Lipid content, lipid class and fatty acid composition of four Southern Ocean cephalopod species – the myopsid Sepioteuthis australis and three oegopsids, Gonatus antarcticus, Moroteuthis robsoni and Todarodes spp. – were analysed. The lipid content of the digestive gland was consistently greater than that of the mantle, and was an order of magnitude greater in oegopsid species. The lipid class and fatty acid composition of the mantle and digestive gland also differed markedly in each species. Digestive gland lipid is likely to be of dietary origin, and large amounts of lipid in the digestive gland of oegopsids may accumulate over time. Thus the digestive gland is a rich source of fatty acid dietary tracers and may provide a history of dietary intake. However, the absolute amount of dietary lipid in the digestive gland of oegopsid species exceeds the absolute lipid content of mantle tissue. Therefore the overall lipid “signature” of an oegopsid may more closely resemble its prey species rather than its mantle tissue. When lipid techniques are used in dietary analysis of teuthophagous predators, squid may not be represented by a unique signature in analyses and their importance in the diets of predators may be underestimated.
84524984
Lipids in selected abyssal benthopelagic animals: links to the epipelagic zone?
Abstract A detailed study of the lipids of selected zooplankton species and scavenging amphipods in the near-bottom water layer (15–100 m above bottom, mab) was carried out at the BENGAL site in late summer 1998. Copepoda were the main contributors to the zooplankton, comprising 75% of the total abundance, followed by Ostracoda and Chaetognatha. Calanoid copepods of the family Metridinidae were predominant and accounted for more than 50% of all copepods. Two types of storage lipids were distinguished: triacylglycerols and wax esters. Ostracoda and the polychaete Vanadis sp. stored exclusively triacylglycerols whilst the bulk of the Copepoda accumulated wax esters, with the exception of the family Aetideidae. In the amphipods both lipid classes were found: Eurythenes gryllus stored wax esters and Paralicella spp. and Orchomene sp. triacylglycerols. The fatty acid composition was characterized by a high level of monounsaturated 18:1 (n—9), which is described as characteristic for animals living in the deeper layers of the water column, and to a lesser degree by 16:1 (n—7) and 20:5 (n—3), which are typical components of diatom lipids, and 22:6 (n—3), typical of dinoflagellates. The ratio of 18:1 (n—9):18:1 (n—7) fatty acids was between 5 and 10 in the copepods and indicates a carnivorous/omnivorous feeding behaviour in this group, whereas the higher ratios of 8–18 in the amphipods confirm their necrophagy. The fatty alcohols of the animals storing wax esters were dominated by the monounsaturated isomers 18:1 (n—9) and 18:1 (n—7). The predominance of wax esters as storage lipids in the deep-sea copepods indicates a strong seasonality in the availability of food. This is supported by the high levels of 16:1 (n—7), 20:5 (n—3) and 22:6 (n—3) fatty acids, which point to there being a direct link between the surface primary production and deep-sea copepods, probably via the rapid deposition of phytodetritus.
84710646
Lipids of Antarctic Ocean amphipods: food chain interactions and the occurrence of novel biomarkers
Abstract Antarctic hyperiid ( Themisto gaudichaudi , Hyperia macrocephalus , and Primno macropa ) and gammarid amphipods ( Eusirus perdentatus and Orchomene rossi ) were collected near Elephant Island, located in the South Shetland Islands, during January and February 1997 and 1998. Polar lipid (PL) was the major lipid class in all amphipods (58–88% of total lipid), except for T. gaudichaudi in which triacylglycerol (TAG) was dominant (62%). Cholesterol was the major sterol in the gammarid amphipods (89–91% of total sterols), and the hyperiid P. macropa (70%). The hyperiids T. gaudichaudi and H. macrocephalus had a more diverse sterol composition including trans -dehydrocholesterol, desmosterol, 24-nordehydrocholesterol, 24-methylcholest-5,22 E -dien-3β-ol, 24-methylenecholesterol, and stanols (mostly cholestanol). Eicosapentaenoic acid [EPA, 20:5( n −3)] and docosahexaenoic acid [DHA, 22:6( n −3)] were the major polyunsaturated fatty acids (PUFA) in all amphipods. The PUFA octadecapentaenoic acid [18:5( n −3)] was not detected in 1997 samples, but comprised 0.3–1.2% in all 1998 samples. The PUFA 18:4( n −3) comprised 0.2–4.2% in all samples from both years. Very long chain PUFA (VLC-PUFA) (C 24 and C 26 ) were not detected in the one 1997 sample but comprised 0.6–2.8% of total fatty acids in almost all 1998 amphipods. Monounsaturated fatty acids included 18:1( n −9)c, 18:1( n −7)c, and 16:1( n −7)c. Principal saturated fatty acids in all amphipods were 16:0, 14:0, and 18:0. Examination of biomarker lipids has helped clarify trophic interactions for these Antarctic amphipods, and revealed annual differences in their food sources.
14261940
Feeding ecology of eastern North Pacific killer whales Orcinus orca from fatty acid, stable isotope, and organochlorine analyses of blubber biopsies
Blubber biopsy samples from eastern North Pacific killer whales Orcinus orca were ana- lyzed for fatty acids, carbon and nitrogen stable isotopes and organochlorine contaminants. Fatty acid profiles were sufficiently distinct among the 3 reported ecotypes ('resident,' 'transient' or 'offshore') to enable individual animals to be correctly classified by ecotype and also by mitochondrial DNA (mtDNA) haplotype. Profiles of PCBs also enabled unambiguous classification of all 3 killer whale ecotypes, but stable isotope values lacked sufficient resolution. Fatty acid, stable isotope and PCB profiles of the resident and transient ecotypes were consistent with those expected for these whales based on their reported dietary preferences (fish for resident whales, marine mammals for transients). In addition, these ecotype profiles exhibited broad similarity across geographical regions, suggesting that the dietary specialization reported for resident and transient whales in the well-studied eastern North Pacific populations also extends to the less-studied killer whales in the western Gulf of Alaska and Aleutian Islands. Killer whales of the same ecotype were also grouped by region of sample col- lection. The mean stable isotope ratios of various regional groups differed considerably, suggesting that the prey preferences of these North Pacific killer whales may be both region and ecotype spe- cific. Furthermore, 3 specific ecotypes of killer whales were found to have measured stable isotope values that were consistent with dietary preferences reported in the literature. Finally, although the offshore population had blubber fatty acid profiles implicating fish as its primary prey, contaminant and stable isotope results were equally congruent with predation on marine mammals.
85630787
Evidence of abalone (Haliotis rubra) diet from combined fatty acid and stable isotope analyses
Abalone are common herbivores throughout temperate and tropical waters, and yet the contribution of red and brown macroalgae to the diet of wild abalone remains unclear. In the northern hemisphere, adult abalone are considered to consume predominantly brown algae, but in the southern hemisphere abalone are thought to prefer red algae. Conventional methods such as gut content analysis and feeding trials provide some insight into diet choice, but the associated biases of these techniques create uncertainty surrounding the aforementioned variability in abalone diet. We use combined stable isotope and fatty acid analysis to determine the relative contribution of red algae, brown algae and detritus/microalgae to the diet of wild abalone in Tasmanian waters. Stable isotopes of carbon suggest that brown algae and/detritus are a more important source of carbon than red algae. Fatty acid analysis confirmed the larger contribution of brown algae to the diet of abalone, and also identified the bacterial and diatom component of detritus to be an important contributor to abalone diet. These results show combined use of chemical tracers to be a promising technique for resolving abalone diet, and challenge current perceptions regarding spatial variability in abalone diet choice.
30633015
Membrane biosynthesis in swimbladders of deep sea fishes Coryphaenoides acrolepis and Antimora rostrata.
1. 
1. Excised tunica interna from the swimbladder of an abyssal fish (Coryphaenoides acrolepis) incorporated acetate-1-14C and squalene-4-3H into membrane lipids, cholesterol, phosphatidyl ethanolamine, phosphatidylcholine, cardiolipin, and to a lesser extent sphingomyelin. 
 
2. 
2. Ultrastructural study of the tunica interna of the swimbladder of another abyssal fish (Antimora rostrata) revealed large cytoplasmic vacuoles lined and filled with “bilayer” membrane. 
 
3. 
3. The membrane-lined vacuoles in the tunica interna cells may be an assembly point for the biosynthesis of the gram quantities of pure “bilayer” membrane found on the interior of the swimbladder.
35017851
The sequential mobilisation and restoration of energy reserves in tissues of Atlantic cod during starvation and refeeding
Summary1.In the early stages of starvation in cod (Gadus morhua L.), liver lipids and the glycogens of liver and white muscle were mobilised simultaneously, but liver lipids were exhausted first. At about that point, proteins began to be mobilised in red and white muscle, and red muscle glycogen also began to decrease. After about 20 weeks at 9°C, the latter was virtually exhausted, leaving muscle proteins as the only source of energy.2.Starvation caused a significant fall in the glucose, lipids and nonesterified fatty acids (NEFA) of the blood. Ketone bodies seemed to be unimportant as sources of energy in starving cod, in contrast to elasmobranchs and mammals. Little change was observed in blood proteins or ninhydrin-positive substances.3.When the cod were refed after starvation, overcompensation occurred in several metabolites, levels rising temporarily to values much higher than in continuously-fed controls. These comprised the glycogen contents of liver, red muscle and white muscle, NEFA in plasma and the RNA/DNA ratios of liver, red muscle and white muscle. Other constituents simply increased until their levels approached those of the controls. Liver lipids during refeeding did not rise above the low levels of starvation until the water content of the white muscle had dropped below about 82%.4.When fish were refed after a shorter starvation period with squid muscle or herring muscle, only those refed with squid showed a significant rise in the muscle glycogen concentrations. Those fed on herring increased their liver lipids the more.5.The differing periods of refeeding which gave rise to maximum values of red muscle glycogen and white muscle glycogen coincided respectively with maximum RNA/DNA ratios, suggesting that the purpose of unusually high glycogen values was to supply the energy for muscle regeneration.
82959181
Gonatid Squids in the Subarctic North Pacific Ecology, Biogeography, Niche Diversity and Role in the Ecosystem
Abstract This review is based on the author's own data and all available published data (mostly Russian and Japanese) on the ecology, biogeography and role in the ecosystem of gonatid squids in the northern North Pacific. For the best studied species, Berryteuthis magister , information is given on size, horizontal and vertical distribution, diel and ontogenetic vertical migrations, maturation, mating, spawning, fecundity, population structure, age, growth, life cycle, horizontal migrations, underwater behaviour, food and feeding, and predators. The assessed biomass and its interannual dynamics and the fisheries importance are also covered. For other, less studied, species of the genera Berryteuthis (B. anonychus), Gonatopsis (three species) and Gonatus (seven species) all available ecological and biogeographical data are included. All species are compared according to their size, horizontal and vertical distribution, spawning habitats, diel vertical migrations and gelatinous degeneration associated with maturation. The “ecological individuality” of each species is evaluated. It is shown that each occupies its own ecological niche but these niches overlap to different degrees. The history of niche divergence in North Pacific gonatids during the Neogene-Pleistocene period is briefly reviewed. Common features are described of the horizontal and vertical distribution, relative abundance and biomass of North Pacific gonatids in general. Their roles in the ecosystem, as predators, prey, competitors and hosts of parasites is evaluated. The total biomass of gonatid squids in the whole subarctic North Pacific and the Russian Far Eastern seas is estimated as approximately 15–20 million t. They contribute some 10–15% of the total production of mesopelagic cephalopods in the World Ocean. Their yearly food consumption is assessed at 100–200 million t. The life cycle of gonatids is shorter and their P/B-coefficient much higher than that of subarctic mesopelagic fishes. As a result, though the squid biomass (calculations for the Okhotsk Sea) is less than 10% of the total mesopelagic fish and squid population, they form 58–67% of annual total fish and squid production. Thus gonatid squids have an important place in the ecosystem of the northern North Pacific and the Far Eastern seas of Russia.
87174090
FOOD AND FEEDING OF JUMBO SQUID DOSIDICUS GIGAS IN THE CENTRAL GULF OF CALIFORNIA DURING 2005 -2007
Stomachcontentswereanalyzedfor249jumbosquid (Dosidicus gigas ) of 35‐80 cm mantle length. All squid were sampled in the central Gulf of California in 2005‐07, primarily on the commercial fishing grounds ofSantaRosaliaduringdifferenttimesoftheyear.Diet offSantaRosaliawasmainlycomposedofmesopelagic micronektonic organisms, mostly the myctophids Benthosema panamense , Triphoturus mexicanus,andthesquid Pterygioteuthis giardi.Pteropodsandcrustaceansmadeup a smaller portion of the diet. Squid sampled elsewhere revealed that the pelagic red crab, Pleuroncodes planipes, and northern anchovy, Engraulis mordax , could also be major dietary items. Cannibalism incidence increased withsquidmantlelength.Weproposethatthemainprey ofjumbosquidinthecentralGulfofCaliforniaderives from the mesopelagic community associated with the upper boundary of the oxygen minimum layer, a welldeveloped midwater feature in this region. In addition, opportunistic foraging on a variety of organisms sup plements their dietary intake. These data are discussed in conjunction with recent electronic tagging data that revealed vertical and horizontal movements of jumbo squid. This work demonstrates a need to study the dynamics of the oxygen minimum layer and the com positionofthedeep-scatteringlayerovertheupperslope
85080738
Towing large nets by single warp at abyssal depths: methods and biological results
Abstract Adequately sampling deep-water nekton is difficult because of the great time required for tows, avoidance of nets by larger animals, and the sparse fauna. These problems have been compounded by the small nets usually used for such sampling. This paper describes the equipment, techniques, difficulties, and results of towing large midwater and bottom trawls single warp at depths below 2000 m from chartered commercial fishing vessels. Use of large nets (107 m 2 mouth pelagic rope trawl and 29.6 m headrope otter trawl) is a method which minimizes the effects on sample sizes and compositions of the above factors. Tows with large opening-closing midwater trawls and otter trawls between 2000 and 4300 m off northern California collected specimens of rare species and unusually large individuals of other species. Included among these are five fish species not previously reported from off California: Bathysaurus mollis (Synodontidae), Barathronus pacificus (Aphyonidae), Echinomacrurus occidentalis (Macrouridae), Dysalotus oligoscolus (Chiasmodontidae), and Bellocia alvifrons (Alepocephalidae). Fishes decreased with depth by numbers of species, numbers of individuals, and by weight. Decapod crustaceans did not show similar trends. Cephalopods were uncommon at all depths sampled. Coryphaenoides filifer (Macrouridae), a nominally benthic fish species, was unexpectedly abundant in midwater between 2000 and 3100 m. It constituted 54.6% of the fish biomass collected at these depths. Its abundance did not appear to be related to sex, size, or reproduction. Food habits of Coryphaenoides armatus and C. yaquinae (Macrouridae), the most abundant benthic fish species, differed. The former ate primarily nekton; the latter, benthic infauna. Occurrence in stomachs of beaks from shallow living squid and of epipelagic barnacles suggests that carrion may form a significant part of the diets of these species. One ripe and five ripening female C. armatus , all longer than 740 mm TL, were collected. Estimated fecundity of the ripest was 6.2 × 10 6 eggs. Based on these and previous captures, C. armatus females mature at a large size, have a high fecundity relative to other macrourids, may not spawn simultaneously, and may be semelparous.
84824924
Diets and standing stocks of benthopelagic fishes at two bathymetrically different midoceanic localities in the northeast Atlantic
Abstract Deep-sea benthopelagic fishes were sampled by trawl and free-fall longline at two latitudinally and bathymetrically separated stations in the northeastern Atlantic. The catch structure and the contents of the fish stomachs were analysed. The northern, 3000 m deep station in the Iceland Basin exceeded the deeper (4500 m) site in terms of demersal fish biomass and abundance by factors of 5 and 10, respectively. Synaphobranchidae of the species Histiobranchus bathybius and several species of Macrouridae contributed to the samples, the latter dominating with Coryphaenoides (Nematonurus) armatus most abundant in the north and with Coryphaenoides (Chalinura) leptolepis in the south. Diet composition was studied for numerical abundance and wet weight of prey organisms. In the Iceland Basin, where two size classes of C. (N.) armatus could be analysed separately, an ontogenetic change in diet was noted. Individuals shorter than 30 cm in length fed mainly on benthic and epibenthic Crustacea whereas the larger specimens showed a high proportion of fish and Cephalopoda in their stomachs. At the southern site (BIOTRANS station in the West European Basin) Amphipoda, fish and Cephalopoda were the main food source. Coryphaenoides (Chalinura) leptolepis fed on Malacostraca and fish at the northern site, but on Polychaeta and Cephalopoda at the southern station. Stomachs of H. bathybius contained food only in the Iceland Basin. Their diet consisted mainly of Malacostraca and Cephalopoda. Despite their state of digestion, most Cephalopoda could be identified by means of their beaks, which also allowed a recalculation of their original size. The taxonomic composition and the size structure led to the assumption that most Cephalopoda were epi- or mesopelagic and had been preyed upon near the bottom as carcasses. The possible trophic position of the predominant benthopelagic fishes in the benthic boundary layer is discussed.
85062983
Deep-sea food web analysis using cross-reacting antisera
The high incidence of unrecognizable prey in the stomachs of deep-sea predators prompted the application of serological methods for identification of trophic connections. Antisera to whole-organism extracts of estuarine taxa cross-reacted with antigenic protein extracts of mid-water and deep-sea taxa along phylogenetically correct lines, indicating their potential as tools for gut contents immunoassay. Stomach, intestine, and rectum contents of grenadiers (Coryphaenoides armatus) trapped at 2500 m in the North Atlantic were analyzed visually and with 32 antisera representing taxa from 10 common deep-sea phyla. While visual analysis only revealed the presence of fluids, parasites, crustacean exoskeletons, and gastropod opercula, the immunoassay indicated the presence of antigenic proteins from holothurian, anemone, gastropod, decapod, and foraminiferan prey in the same samples. This qualitative serological identification of prey at non-specific taxonomic levels provides evidence that benthic predation may be important within deep-sea communities. The immunoassay technique, although not a panacea for elucidating food web dynamics in remote environments, may be useful when other methods fail to identify trophic pathways.
44953518
Toxins from sea cucumbers (holothuroids): chemical structures, properties, taxonomic distribution, biosynthesis and evolution.
Studies on structures, biological activities, chemical properties, taxonomic distribution, biosynthesis, and evolution of toxins from sea cucumbers (the phylum Echinodermata, the class Holothurioidea) were reviewed with special emphasis on recent results from our laboratory. These toxins are triterpene oligoglycosides having very often one or several sulfate groups in carbohydrate moieties. Their aglycones belong to lanostane derivatives and sometimes contain shortened side chains. Many aglycones are labile in the acid medium. There is a relationship between structures of the glycosides and taxonomic positions of corresponding animals, producers of these toxins. Toxins from sea cucumbers act on delta 5-sterol-containing biological membranes with the formation of glycoside-sterol complexes followed by the disturbance of membrane permeability and inhibition of activities of some membrane enzymes. The presence of the toxins causes the alterations in membrane sterol compositions of toxic sea cucumbers in comparison with non-toxic species. These alterations include the change of delta 5-sterols for those having 7(8)- and 9(11)-double bonds as well as biotransformation of a part of free sterol fractions into sterol sulfates and sterol xylosides.
85807966
Benthic boundary layer communities and carbon cycling at abyssal depths in the central North Pacific
Cycling of carbon through the benthic boundary layer (BBL) community in the deep sea is poorly understood. Until now, attempts to summarize the flow of organic C in these communities have relied primarily on data collected from various deep-sea areas. The one BBL community where the organic C pools and fluxes are best defined is in the central North Pacific, north of the Hawaiian Islands. This data base was combined with new estimates of standing stocks and organic C fluxes to construct an organic C budget for the bottom 600 m of the water column and the sediments, using net input from sinking particulate organic C (POC) and exchanges between 12 compartments. The largest standing stocks of C (dissolved organic C, suspended POC, and POC) were in the water and surface sediments (9.1 x lo8 g C km-2), exceeding that in the 10 consumer groups by almost four orders of magnitude. Of the consumer groups, the sediment nanobiota, meiofauna, and epibenthic megafauna had the most organic C and the macrofauna had the least. Fluxes into the consumer groups, as estimated from respiration rates, were highest in the sediment community, bacterioplankton, and epibenthic megafauna. The net flux of POC into the BBL (supply) ranged from -74 to + 1,268 g C km 2 d-l, which was generally insufficient to match the combined fluxes into the BBL consumer groups (demand) of 998-3,3 15 g C krnm2 d I. Other sources of organic C to fuel the demand of the BBL community are analyzed, including active transport by migrating abyssopelagic animals which might significantly augment the POC flux into the BBL at this oligotrophic midgyre station.
4328980
Changes in fisheries discard rates and seabird communities
It is clear that discards from commercial fisheries are a key food resource for many seabird species around the world. But predicting the response of seabird communities to changes in discard rates is problematic and requires historical data to elucidate the confounding effects of other, more ‘natural’ ecological processes. In the North Sea, declining stocks, changes in technical measures, changes in population structure and the establishment of a recovery programme for cod (Gadus morhua) will alter the amount of fish discarded. This region also supports internationally important populations of seabirds, some of which feed extensively, but facultatively, on discards, in particular on undersized haddock (Melanogrammus aeglefinus) and whiting (Merlangius merlangus). Here we use long-term data sets from the northern North Sea to show that there is a direct link between discard availability and discard use by a generalist predator and scavenger—the great skua (Stercorarius skua). Reduced rates of discarding, particularly when coupled with reduced availability of small shoaling pelagic fish such as sandeel (Ammodytes marinus), result in an increase in predation by great skuas on other birds. This switching of prey by a facultative scavenger presents a potentially serious threat to some seabird communities.