The effect of hurricanes on body size in Puerto Rico fish populations

Abstract. Hurricanes Irma and Maria were category 5 hurricanes that devastated parts of Central America in September 2017. Hurricane Irma passed northern Puerto Rico on September 6; Maria reached Puerto Rico as a category 4 hurricane on 20 Sep 2017. These hurricanes had devastating effects on the people living in Puerto Rico, but less is known about how the hurricanes impacted Puerto Rico's wildlife. The National Ecological Observatory Network (NEON) provides a large ecological database covering all American states and Puerto Rico. NEON includes comprehensive information about fish species and environmental variables at multiple sites collected at time periods from late 2014 to present. Aquatic sample collection in Puerto Rico has been performed at Rio Guilarte and Rio Cupeyes. Data collection from these two sites occurred around the same time before the hurricanes in February 2017, and also occurred shortly after the hurricanes. Gambusia affinis (western mosquitofish), Xiphophorus hellerii (green swordtail), and Poecilia reticulata (guppy) were collected in Rio Guilarte. Agonostomus monticola (mountain mullet) was collected in Rio Cupeyes. The focus of this study was to determine if the hurricanes had an impact on the mean length of each fish species, which would suggest eco-evolutionary effects of hurricanes on fish populations. The results indicate that while all four species' lengths decreased, on average, only the decreases in green swordtail and mountain mullet were significant. Hurricanes, storms, and floods are happening at increasingly higher severity. This analysis identifies direct biological effects caused by severe short-term ecological disruptions on multiple fish species.