Date of Award

2013

Degree Type

Thesis

Degree Name

Master of Science in Oceanography

Department

Oceanography

First Advisor

Jeremy S. Collie

Abstract

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 physiologically 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. Species that usually inhabit the bay during the winter, spring, and early summer shifted towards later seasonal distributions in recent years; fall species shifted towards earlier seasonal distribution. 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. The small spatial scale of this study allows for better examination of local variability in fish species’ responses to ocean warming relative to similar regional studies.

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