Diversification of life history strategy within a species is thought to produce more temporally stable populations because of the complementary or independent dynamics among population components in their response to environmental perturbation. The partitioning of risk amongst population components, known as the ‘portfolio effect’, favors long-term population resiliency. In the event of disturbance, minority components may be able to ‘rescue’ the threatened population, but this ability is contingent upon the degree of connectivity between components. The first year of life, especially, is an influential time period for determining year-class strength in many fish species. High mortality rates during this stage act as a gauntlet, dampening interannual recruitment variability. Intra-population modalities in spawning and early habitat use create diverse population components, that allow populations to provision juveniles year after year and contribute to the accumulation of adult biomass in the face of environmental variability during the first year of life. Winter flounder (Psuedopleuronectes americanus, Walbaum 1792), a coastal flatfish species of economic and cultural importance, have declined to less than 11% of their historic abundance in the Southern New England/Mid-Atlantic region of the United States. Unusually high post-settlement mortality is thought to impose a critical recruitment bottleneck on the population; potentially stalling recovery of winter flounder populations despite strict management measures. I examined the consequences of environmental variability on survival and growth of young-of-the-year winter flounder, and how they exhibit the portfolio effect by distributing productivity spatially across habitats, and temporally through the production of split cohorts (i.e., seasonal pulses of eggs and larvae). I examined the degree of connectivity between population components thought to be at risk for local extirpation, in an effort to assess the potential for resilience within this species and the implications for management and recovery.
|Advisor:||McElroy, Anne E., Frisk, Michael G.|
|Commitee:||Cerrato, Robert, Feldheim, Kevin, O'Leary, Shannon|
|School:||State University of New York at Stony Brook|
|Department:||Marine and Atmospheric Science|
|School Location:||United States -- New York|
|Source:||DAI-B 82/9(E), Dissertation Abstracts International|
|Subjects:||Ecology, Environmental science, Wildlife Management|
|Keywords:||Environmental biology, Fisheries science, Winter flounder, Population genetics, Psuedopleuronectes americanus|
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