7201
The surface MRC density and MRC fractional area were lower in fish from FU20 , FU30 , FU40 and FU50 than in those from the reference site ( FU10 ) in the winter , and some variability between the sites was observed in the summer .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None