| dcterms.abstract | Winter Flounder have declined to less than 11% of their historical abundance in offshore areas and have experienced severe declines and inbreeding in coastal subpopulations. Overfishing, unfavorable environmental conditions and predation have been suggested as drivers of this species’ decline. Stocks that migrate inshore to spawn exhibit metapopulation structure, migration diversity and localized responses to large-scale environmental drivers. Understanding metapopulation structure and disparate migratory behavior is vital to understanding the species’ dynamics in the region. We used acoustic telemetry to evaluate migratory types and natal homing in adult Winter Flounder (n = 76) in Mattituck Creek, NY. Telemetry results showed 17% of the tagged individuals displayed resident behavior and remained in the creek year round despite average temperatures reaching 28°C, which exceeds the species’ published thermal tolerance. Alternatively, the migratory group (~83% of the tagged individuals), started to leave the system in the spring when the average water temperature reached 12°C. Drivers of migration into and out of the creek included temperature, lunar cycle, photoperiod, date, and year. Natal homing was demonstrated in 38% of the migratory individuals, returning to the creek only five months after leaving. Estimated spawning of Winter Flounder took place as early as November and continued through April. While in the creek, tagged Winter Flounder exhibited limited movements spending over half of their residency at one station (detection radius 500 m). Additionally, to determine if Winter Flounder can find temperature refuge in the creek during periods when temperatures exceed the species’ tolerance, we evaluated internal body temperature relative to water temperatures (N = 23) on a long-term scale and sediment temperature (N = 10) on a short-term scale utilizing temperature sensing acoustic tags. All Winter Flounder exhibited a difference between internal temperature and water temperature; these differences were seasonally dependent. Over a period of three months, sediment temperatures ranging from 30 mm to 90 mm deep exhibited values similar to internal body temperature more often than water temperature. These results provide further insight into Winter Flounder movements, residency, spawning behavior, and thermoregulation in the mid-Atlantic region and provide vital information for management of this depleted species. | |
