Winter flounder ecology

IMAG00191

Winter flounder captured in Mattituck Creek, New York, March, 2015.

 

IMAG00190 (2)

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 Recent paper abstracts

Gallagher, B.K., L.A. Hice, A.E. McElroy, R.M. Cerrato, M.G. Frisk (In Press). Factors Influencing Daily Growth in Young-of-the-Year Winter Flounder along an Urban Gradient Revealed Using Hierarchical Linear Models. Marine and Coastal Fisheries.

 Abstract: Growth during early life history plays a key role in the recruitment dynamics of marine fishes, however, the effects of environmental stressors on growth are often difficult to quantify. In this study, increment widths from sagittal otoliths were used as a proxy for daily growth in 103 young-of-the-year (YOY) winter flounder (Pseudopleuronectes americanus) collected over a two year period from three sites in Long Island, NY. We hypothesized that we would observe different growth patterns among bays due to an environmental gradient driven primarily by contaminant loadings and environmental stressors in our study sites. Hierarchical linear models (HLM) were utilized to associate individual attributes (ontogeny, condition, and gene expression) to daily growth patterns during each year. As expected, daily growth generally displayed a negative relationship with age and daily temperature, although the effect of temperature was much more variable. Out of fourteen individual attributes, settlement date, age at capture, the condition indices Fulton’s K and hepatosomatic index, and the expression of genes associated with immune response (pleurocidin), contaminant exposure (vitellogenin, cytochrome P540A) and glucose and glycogen metabolism (glycerol-3-phosphate dehydrogenase) were observed to significantly and consistently affect growth at a given age and/or temperature. Results provide evidence of differential growth based on date of settlement and condition, and the molecular indicators of stress suggest that growth is also strongly influenced by habitat quality. There were significantly different relationships between individual attributes and growth among bays, but these did not always reflect the proposed environmental gradient. Together, the results suggest that recruitment in Long Island bays is likely being limited by unfavorable environmental conditions. Furthermore, this study highlights the utility of HLM in analyzing complex daily growth data in juvenile fish, which may be applicable to other species.

Yencho, M.A., A. Jordaan, R.M. Cerrato, H. Baumann and M.G. Frisk (In press). Growth and mortality in coastal populations of Winter Flounder: Implications for recovery of a depleted population. Marine and Coastal Fisheries.
Abstract: We studied growth, mortality, and settlement distributions of juvenile Winter Flounder Pseudopleuronectes americanus in two bays of Long Island, New York, to better understand localized population dynamics of a species experiencing a protracted population decline. Juvenile mortality in Long Island bays ranged between 0.02 and 0.04 per day and was as high as or higher than values reported for other systems. Settlement distributions had multiple 25 peaks (cohorts) occurring between March and late July in 2007 and between February and May in 2008. The presence of multiple cohorts limited the usefulness of field-derived, length-based estimates of growth, resulting in unrealistic values compared with otolith-based measures (field based: ¡0.05 to 0.25 cm/d; otolith based: 0.05–0.06 cm/d). Thus, we recommend the use of otolith methods or the repeated measurement of individuals to estimate growth of juvenile Winter Flounder. Otolith-based growth rate was significantly higher for Port Jefferson Harbor 30 during 2007 than for all other year £ location combinations. Together with previous research showing genetic differentiation and migratory diversity, our finding of multiple spawning cohorts in Long Island Winter Flounder suggests a degree of isolation, and local management will be needed to support healthy populations. Future research to determine adult spawning, migratory behavior, stock structure, duration of the larval period, and settlement
timing is required to unravel the complex behavior of Winter Flounder.
McElroy, A.E., L.A. Hice**, M.G. Frisk, S.L. Purcell, and M.D. Fast (In Press). Spatial patterns in markers of contaminant exposure, glucose and glycogen metabolism and immunological response in juvenile winter flounder (Pseudopleuronectes americanus). Comparative Biochemistry and Physiology Part D: Genomics and Proteomics.
Abstract: Inshore winter flounder (Pseudoplueronectes americanus) populations in NY, USA have reached record low numbers in recent years, and recruitment into the fishery appears to be limited by survival of post-settlement juvenile fish. In order to identify cellular pathways associated with site-specific variation in condition and mortality, we examined differential mRNA expression in juvenile winter flounder collected from six different bays across a gradient in human population density and sewage inputs. Illumina sequencing of pooled samples of flounder from contrasting degraded sites and less impacted sites was used to guide our choice of targets for qPCR analysis. 253 transcripts of >100 bp were differentially expressed, with 60% showing strong homology to mostly teleost sequences within the NCBI database. Based on these data, transcripts representing nine genes of interest associated with contaminant exposure, immune response and glucose and glycogen metabolism were examined by qPCR in individual flounder from each site. Statistically significant site-specific differences were observed in expression of all but one gene, although patterns in expression were complex with only one (vitellogenin), demonstrating a west to east gradient consistent with known loadings of municipal sewage effluent. Principal components analysis (PCA) identified relationships among the genes evaluated. Our data indicate that juvenile winter flounder are responding to estrogenic chemicals in more urbanized coastal bays, and suggests potential mechanistic links between immune response, contaminant exposure and energy metabolism.

O’Leary SJ, Hice LA, Feldheim KA, Frisk MG, McElroy AE, et al. (2013) Severe Inbreeding and Small Effective Number of Breeders in a Formerly Abundant Marine Fish. PLoS ONE 8(6): e66126.

Abstract: In contrast to freshwater fish it is presumed that marine fish are unlikely to spawn with close relatives due to the dilution effect of large breeding populations and their propensity for movement and reproductive mixing. Inbreeding is therefore not typically a focal concern of marine fish management. We measured the effective number of breeders in 6 New York estuaries for winter flounder (Pseudopleuronectes americanus), a formerly abundant fish, using 11 microsatellite markers (6-56 alleles per locus). The effective number of breeders for 1-2 years was remarkably small, with point estimates ranging from 65-289 individuals. Excess homozygosity was detected at 10 loci in all bays (F-IS = 0.169-0.283) and individuals exhibited high average internal relatedness (IR; mean = 0.226). These both indicate that inbreeding is very common in all bays, after testing for and ruling out alternative explanations such as technical and sampling artifacts. This study demonstrates that even historically common marine fish can be prone to inbreeding, a factor that should be considered in fisheries management and conservation plans.

Collier, J.L., S.P. Fitzgerald, L.A. Hice, M.G. Frisk, and A.E. McElroy (2014). A New PCR-based Method Shows that Blue Crabs (Callinectes sapidus) Prey on Winter Flounder (Pseudopleuronectes americanus Walbaum)). PLoS ONE.
Abstract: Winter flounder (Pseudopleuronectes americanus) once supported robust commercial and recreational fisheries in the New York (USA) region, but since the 1990s populations have been in decline. Available data show that settlement of young-of-the-year winter flounder has not declined as sharply as adult abundance, suggesting that juveniles are experiencing higher mortality following settlement. The recent increase of blue crab (Callinectes sapidus) abundance in the New York region raises the possibility that new sources of predation may be contributing to juvenile winter flounder mortality. To investigate this possibility we developed and validated a method to specifically detect winter flounder mitochondrial control region DNA sequences in the gut contents of blue crabs. A survey of 55 crabs collected from Shinnecock Bay (along the south shore of Long Island, New York) in July, August, and September of 2011 showed that 12 of 42 blue crabs (28.6%) from which PCR-amplifiable DNA was recovered had consumed winter flounder in the wild, empirically supporting the trophic link between these species that has been widely speculated to exist. This technique overcomes difficulties with visual identification of the often unrecognizable gut contents of decapod crustaceans, and modifications of this approach offer valuable tools to more broadly address their feeding habits on a wide variety of species.

Sagarese, S.R. and M.G. Frisk (2011). Movements and residence of adult winter flounder, Pseudopleuronectes americanus, within a Long Island (NY) Estuary. Marine and Coastal Fisheries 3:295-306.

Abstract: We implanted individually coded acoustic transmitters into 40 adult winter flounder Pseudopleuronectes americanus (mean total length = 320 mm; range = 240–423 mm) and monitored them by use of passive acoustic telemetry from September 2007 to April 2009 to classify spatial and temporal movement patterns and quantify residency in Shinnecock Bay, eastern Long Island, New York. Overall, 94,250 valid detections were received. Winter flounder remained inshore, and 89% of the total detections occurred between May and October when bottom water temperature exceeded 15◦C. Residency in Shinnecock Bay was dependent on time of release and varied greatly from a few weeks to more than 6 months; total presence (number of days on which individual fish were detected within the bay) averaged 22.0 d (range = 1–132 d). Tracked winter flounder were classified as exhibiting three movement patterns: (1) inner bay movements (short term versus long term), (2) dispersal to offshore waters, and (3) connectivity to other inshore areas. The first two patterns were consistent with historical notions of spatially overlapping resident and migratory individuals, whereas fish that displayed the third pattern may have exhibited a larger home range. These results provide insight into winter flounder movements, residency, and stock structure in a coastal bay of Long Island and provide important information for management. The interaction of exploitation and divergent migration behaviors may be a factor contributing to the winter flounder’s decline in Long Island bays; however, much more work will be required to obtain a full understanding of the spatial behavior and stock structure of this species.

Sagarese, S.R. Cerrato, R.M. and M.G. Frisk (2011). Diet Composition and Feeding Habits of Common Fishes in Long Island Bays, New York. Northeastern Naturalist.

Abstract:  Developing models in support of ecosystem-based management requires knowledge of trophic dynamics of ecologically important species. A paucity of data on these dynamics for Long Island fi nfi sh is hindering development of ecosystem models required by recent legislation. In this study, we analyzed stomach contents of common fishes collected from Port Jefferson Harbor, Great South Bay, and Shinnecock Bay between May and October of 2007 and 2008. General diet composition was described by percent by number (%N), percent by weight (%W) and percent frequency of occurrence (%O) for seven species: Paralichthys dentatus (Summer Flounder), young-of-the-year (YOY) Pomatomus saltatrix(Bluefi sh), Prionotus evolans (Striped Searobin), Stenotomus chrysops (Scup), Scophthalmus aquosus (Windowpane Flounder), Raja eglanteria (Clearnose Skate), and Morone saxatilis (Striped Bass). Temporal diet composition was estimated for the consistently abundant YOY Bluefi sh, Summer Flounder, and Scup, where most nseason > 25. Subsampling of large catches of YOY Bluefi sh and Scup led to investigation of diet composition by cluster sampling. Important prey included Crangon sp. (sand shrimp), Cancer irroratus (Rock Crab), and forage fi shes.Pseudopleuronectes americanus (Winter Flounder), once a common prey item in stomachs of piscivorous Long Island fi shes, contributed ≤ 6.7 %O and ≤ 1.6 %W to the diets of Summer Flounder, Striped Searobin, Striped Bass, and YOY Bluefi sh. These changes may be due to shifts in the abundance of prey items or changes in spatial overlap of predator and prey.