Temperature-Related Changes In Species Composition Of Juvenile Finfish On A Rock Reef In Long Island Sound

We assessed changes in relative abundance of juvenile fish on a natural cobble and boulder reef near Milford, Connecticut, in summer (June-August) during the years 2004-2008 and in 2016. Fish traps, used to sample structure-oriented fish, were soaked for similar to 24 h 2-3 times per week. Catch per unit of effort was used as an index of fish abundance and to standardize differences in sampling effort among study years. Juvenile finfish assemblages during 2004 and 2005 differed most in species composition from the assemblage in 2016. Abundance of 2 warm-adapted species, the black sea bass (Centropristis striata) and the oyster toadfish (Opsanus tau), was observed to increase over the study period, and numbers of cunner (Tautogolabrus adspersus) and other cold-adapted species declined. Water temperature was a statistically significant predictor of changes in finfish assemblage over the period of this study, explaining 8.6% of the observed variation in species composition in the data set. A widely documented trend of gradually warming water temperatures from a local, long-term temperature record was consistent with observations from this study of warm-adapted and cold-adapted fish species on a natural rock reef in Long Island Sound.