Impacts of Changing Inshore Water Temperature on Phenology and Thermal Preferences of Fish Species in Narragansett Bay, Rhode Island

The University of Rhode Island Graduate School of Oceanography Fish trawl survey of Narragansett Bay, Rhode Island, USA, provides a unique weekly time series of fish and invertebrate abundances over the last five decades (1959-present).  Conditions in the bay changed in numerous ways since 1959 including increasing sea surface temperature and declining chlorophyll concentrations.  With rising ocean temperatures, fish species may change phenology, abundance, or adapt to differing temperature regimes.  A comparison of species distributions according to water temperature and week of year is made with single-parameter quotient analyses to assess the magnitude and patterns of temporal changes.  Winter, spring and early summer species’ seasonal distributions shifted later in the year while fall species moved earlier in the latter half of the time series. In general, pelagic feeding species’ abundances increased while demersal feeders declined.  Results suggest species alter phenology and thermal preferences to follow changing seasonal distribution of chlorophyll, used as a proxy for bay production.