Impact of elevated temperature on the growth, survival, and trophic dynamics of winter flounder larvae: a mesocosm study

Abstract

Winter flounder (Pseudopleuronectes americanus) is a dominant commercial fish in Narragansett Bay, Rhode Island, and yet factors controlling its recruitment remain unclear. An experiment was conducted with six 13-m3 land-based mesocosms (5 m deep) from February to April 1997 to address the impact of increased temperature (+3°C) on growth, survival, and trophic dynamics of winter flounder larvae. Objectives were to determine if warmer winter temperatures result in lower survival of winter flounder as a result of increased predator activity or if temperature-induced alterations in the food web result in greater food availability, perhaps leading to increased survival. Analyses of variance revealed significant (P < 0.05) or near-significant (P < 0.10) differences in phytoplankton and zooplankton abundance and biomass between warm and cool mesocosms. Winter flounder egg survival, percent hatch, time to hatch, and initial size were significantly greater in cool systems (P < 0.05). Mortality rates were lower in...