Spawning behavior reveals bet-hedging across migration modalities in a coastal flatfish

Tara Dolan and Michael G Frisk, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, Stony Brook, NY, Kevin Feldheim, Field Museum of Natural History, Shannon J O'Leary, St Anselm College, Catherine Fede, NYSDEC, Anne McElroy, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY

Background/Question/Methods
The expression of alternative life-history strategies can be advantageous for a species that experiences fluctuating environmental conditions. Intra-species differences in migration propensity and the timing of spawning create diverse population components which are able to respond plastically to environmental variability, promoting long-term stability within the population. This diversity occurs in some fish species in the form of partial migration, wherein only a portion of the population undertakes migration between estuarine and oceanic habitats. Another behavior that results in intra-population diversity is the production of split cohorts (episodic pulses of eggs and larvae within a season). The production of more than one cohort within a season ensures that at least some larvae will overlap with environmental conditions favorable to survival, allowing these populations to remain stable over time in the face of environmental variability. A concern for the assessment and management of winter flounder (Pseudopleuronectes americanus), is whether partial migration manifests in productivity isolation between migration contingents and whether cohorts produced at different times of the year are produced by different spawning contingents. First, we describe the genetic architecture winter flounder populations within five bays in Long Island, NY. Then we characterized intra-specific behavioral diversity in migration status using acoustic telemetry in one of those systems and sampled young-of-the-year using a beam trawl survey following the season those individuals were spawned. We genotyped resident and migrant adult winter flounder to determine the degree of admixture between the behavioral contingents. We assess the degree of genetic exchange between these cohorts of young-of-the-year to infer whether migration diversity is genetically determined.

Results/Conclusions
Our results reveal a greater connectivity between population components than was previously thought to exist for winter flounder. Through parentage analysis, we show for the first time in this species that resident and migrant individuals contribute to both cohorts. Including the role of behavior in mediating population connectivity will lead to more accurate interpretation of the causes and consequences of changes in fisheries productivity, and thus help us design more accurate assessment and effective management strategies.