Time course of oocyte development in winter flounder Pseudopleuronectes americanus and spawning seasonality for the Gulf of Maine, Georges Bank and southern New England stocks

2014 ◽  
Vol 85 (2) ◽  
pp. 421-445 ◽  
Author(s):  
Y. K. Press ◽  
R. S. McBride ◽  
M. J. Wuenschel
2020 ◽  
Vol 77 (7) ◽  
pp. 1189-1200
Author(s):  
Matthew R. Siskey ◽  
Michael G. Frisk ◽  
Robert M. Cerrato ◽  
Karin E. Limburg

The southern New England – mid-Atlantic (SNE–MA) stock of winter flounder (Pseudopleuronectes americanus) collapsed in the 1990s without discernable recovery to date. Owing to the lack of recovery, consideration of population subcomponents, which are currently ignored in fisheries stock structure definitions, may be necessary for rebuilding. We used the otolith chemistry tracer manganese–calcium ratios (Mn/Ca) to estimate inshore- versus ocean-nursery contributions of 77.3%/22.7% in SNE–MA, 15.7%/84.3% in the Gulf of Maine (GOM), and 60.0%/40.0% in Georges Bank (GB). In addition, we used strontium–calcium ratios (Sr/Ca) to estimate migratory- and resident-contingent membership of nursery-classified fish. Across all stocks, 30.2% of fish were classified as bay residents, 25.2% as bay migrants, 25.8% as ocean residents, and 18.8% as ocean migrants. Finally, model selection indicated that both nursery-specific and contingent-specific growth models were more appropriate than a common model. Nursery-specific models exhibited increasing deviations in length with age. Contingent-specific model reflected moderate differences at the youngest ages but convergence at older ages. These findings are informative for the population structure and migration ecology of winter flounder; however, simulation is required to determine whether partial migration and substock structure are necessary inputs for sustainable fisheries management.


2005 ◽  
Vol 62 (7) ◽  
pp. 1394-1407 ◽  
Author(s):  
Jon Brodziak ◽  
Loretta O'Brien

Abstract We evaluated the influence of environmental factors on recruits per spawner (RS) anomalies of 12 New England groundfish stocks. Nonparametric methods were used to analyse time-series of RS anomalies derived from stock-recruitment data in recent assessments. The 12 stocks occur in three geographic regions: the Gulf of Maine (cod Gadus morhua, redfish Sebastes fasciatus, winter flounder Pseudopleuronectes americanus, American plaice Hippoglossoides platessoides, witch flounder Glyptocephalus cynoglossus, and yellowtail flounder Limanda ferruginea), Georges Bank (cod, haddock Melanogrammus aeglefinus, and yellowtail flounder), and Southern New England (summer flounder Paralichthys dentatus, yellowtail flounder, and winter flounder). Randomization tests were applied to detect years when RS anomalies were unusually high or low for comparison with oceanographic conditions such as the 1998 intrusion of Labrador Subarctic Slope water into the Gulf of Maine region. Randomization methods were also used to evaluate the central tendency and dispersion of all RS anomalies across stocks. Average RS anomalies were significantly positive in 1987 across stocks and regions, indicating that environmental forcing was coherent and exceptional in that year. Responses of RS values of individual stocks to lagged and contemporaneous environmental variables such as the North Atlantic Oscillation (NAO) index, water temperature, windstress, and shelf water volume anomalies were evaluated using generalized additive models. Overall, the NAO forward-lagged by 2 years had the largest impact on RS anomalies. This apparent effect is notable because it could provide a leading indicator of RS anomalies for some commercially exploited stocks. In particular, the three primary groundfish stocks on Georges Bank (cod, haddock, and yellowtail flounder) all exhibited positive RS anomalies when the NAO2 variable was positive.


2000 ◽  
Vol 57 (6) ◽  
pp. 1307-1319 ◽  
Author(s):  
Daniel S Holland

An empirically estimated fleet dynamics model for New England trawlers is integrated with spatial, age-structured models of primary groundfish species on Georges Banks, southern New England, and the Gulf of Maine. This bioeconomic model is used to explore how permanent marine sanctuaries on Georges Bank might affect catches, revenues, and spawning stock of principal groundfish species in New England. The simulations explore how the location of sanctuaries relative to major ports and their orientation relative to seasonal movement patterns of fish stocks impact their effectiveness and the distribution of benefits across groups of fishers from different ports. The simulation results also demonstrate that the impacts of sanctuaries can vary greatly across species, sometimes increasing yields for some while decreasing yields for others. While the specific results from the simulations reflect the characteristics of the New England groundfish fishery, the modeling methodology and some general conclusions are applicable to other fisheries.


1989 ◽  
Vol 67 (7) ◽  
pp. 1715-1724 ◽  
Author(s):  
Michael P. Fahay ◽  
Kenneth W. Able

Our interpretation of the pattern of white hake spawning seasonality, habitat use, and growth of young of the year in the Gulf of Maine – Georges Bank area is based on analyses of extensive collections of early life history stages during 1984–1987 and on comparisons with studies conducted in Canadian waters. Eggs or larvae of Urophycis tenuis were not found at any time in the study area, but pelagic juveniles were abundant in May–June and size distributions indicated a shoreward migration with growth. Recruitment to nearshore areas was detected in June–July and the rate of growth for demersal juveniles was calculated to average 1.02 mm/day in the first summer. Spawning of this species during August–September on the Scotian Shelf does not appear to influence the Gulf of Maine population but, instead, appears to involve a separate stock with a different spawning schedule. It is concluded that spawning in continental slope regions south of the Scotian Shelf, Georges Bank, and southern New England during early spring results in recruitment to nearshore areas of the Gulf of Maine and southern New England. This spawning event also provides pelagic juveniles to the Scotian Shelf prior to the onset of local spawning there.


2008 ◽  
Vol 65 (3) ◽  
pp. 340-351 ◽  
Author(s):  
John P Manderson

The spatial scales at which the dynamics of subpopulations are synchronized affect regional population persistence and reflect the operational spatial scales of factors regulating populations. I examined phase synchrony in the fluctuations of age-0 winter flounder (Pseudopleuronectes americanus) production among 19 southern New England (SNE), USA, coastal nurseries. From 1990 to 2004, nursery production was synchronized at scales up to ~200 km based on spatial trends in cross-correlations of first-differenced age-0 abundance time series. However, sliding window analysis of 1975–2005 time series collected in six nurseries ≤55 km apart in northern SNE indicated that synchrony increased from low to high values in the early 1990s. Synchrony in production also increased among three nurseries ≤65 km apart in southern SNE from 1984 to 2004. Thus, interannual fluctuations in nursery production appeared to become synchronized at coarser spatial scales throughout SNE during the 1990s. This coarsening of the spatial scale of control of winter flounder nursery production was coincident with an increase in the frequency of springs with warm temperatures believed to negatively affect early life history processes. Spatial synchronization of winter flounder nursery ground production could destabilize the age-class structure and population dynamics in the region.


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