A NOTE ON THE EFFECT OF TEMPERATURE AND SALINITY ON THE HATCHING OF THE EGGS OF THE WINTER FLOUNDER: (PSEUDOPLEURONECTES AMERICANUS WALBAUM)

1929 ◽  
Vol 4 (1) ◽  
pp. 137-141 ◽  
Author(s):  
W. C. M. SCOTT
Keyword(s):  
Winter Flounder ◽  
Effect Of Temperature ◽  
Pseudopleuronectes Americanus

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Investigating spatial variation and temperature effects on maturity of female winter flounder (Pseudopleuronectes americanus) using generalized additive models

2014 ◽  
Vol 71 (9) ◽  
pp. 1279-1290 ◽  
Author(s):  
Megan V. Winton ◽  
Mark J. Wuenschel ◽  
Richard S. McBride
Keyword(s):  
Spatial Structure ◽  
Spatial Variation ◽  
Clustering Algorithm ◽  
Generalized Additive Models ◽  
Additive Models ◽  
Winter Flounder ◽  
Effect Of Temperature ◽  
Spatial Effects ◽  
Age At Maturity ◽  
Pseudopleuronectes Americanus

Generalized additive models were used to investigate fine-scale spatial variation in female maturity across the three United States’ winter flounder (Pseudopleuronectes americanus) stocks. The effect of temperature on maturity was also investigated. Maturity models explicitly incorporating spatial structure performed better than “traditional” methods incorporating spatial effects by aggregating data according to predefined stock boundaries. Models including temperature explained more of the variability in maturity than those based only on fish size or age but did not improve fit over models incorporating spatial structure. Based on the size- and age-at-maturity estimates from the spatially explicit models, distinct subareas were objectively identified using a spatially constrained clustering algorithm. The results suggested greater variation in size- and age-at-maturity within than between existing stock areas. The approach outlined here provides a method for identifying areas with different vital rates without the need to presume subjective boundaries.

Predation on winter flounder (Pseudopleuronectes americanus) eggs by the sand shrimp (Crangon septemspinosa)

2005 ◽  
Vol 62 (7) ◽  
pp. 1611-1625 ◽  
Author(s):  
David L Taylor ◽  
Donald J Danila
Keyword(s):  
Deterministic Model ◽  
Size Structure ◽  
Early Stage ◽  
Winter Flounder ◽  
Spawning Season ◽  
Effect Of Temperature ◽  
Feeding Rates ◽  
Pseudopleuronectes Americanus ◽  
Egg Mortality ◽  
Crangon Septemspinosa

This study estimated rates of sand shrimp (Crangon septemspinosa) predation on winter flounder (Pseudopleuronectes americanus) eggs and examined the effect of temperature on density-dependent mortality of early-stage flounder. In laboratory experiments, shrimp feeding rates on flounder eggs were positively correlated with temperature and shrimp size. Immunological assays of shrimp stomach contents indicated that 7.2% of shrimp collected from the Niantic River (Connecticut) had flounder eggs in their stomachs. Incidence of egg predation was highest in February (20%) and decreased continuously into early April (1.2%). In a deterministic model simulating predator-induced mortality of flounder eggs during a spawning season, shrimp consumed 0.4%–49.7% of the total flounder spawn. Variations in shrimp population abundance and size structure accounted for the greatest variability in egg mortality. Water temperature during the spawning season presumably alters the population dynamics of early-stage flounder. In a long-term survey, the number of yolk-sac flounder larvae in warm years (≥4.3 °C) was depressed at high egg densities, indicating strong compensatory processes that increased egg mortality and limited the abundance of larvae. Failure of flounder to produce strong year-classes of larvae during warm years, possibly resulting from altered trophic dynamics, may explain the inability of stocks to recover from previous overexploitation.

The Winter Flounder (Pseudopleuronectes americanus) in Long Pond, Conception Bay, Newfoundland

1971 ◽  
Vol 28 (8) ◽  
pp. 1153-1165 ◽  
Author(s):  
V. S. Kennedy ◽  
D. H. Steele
Keyword(s):  
Food Intake ◽  
Growth Rates ◽  
Plant Material ◽  
Early Growth ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Food Items ◽  
Fish Remains ◽  
Males And Females ◽  
Conception Bay

Monthly samples of winter flounder taken in Long Pond from November 1962 to October 1963 indicated that the flounder moved into deeper water (7–10 m) during the summer and returned to shallow water (1–2 m) from September to June. These movements corresponded to the end of the spawning season and the ripening of the gonads respectively. Spawning occurred from March until early June, most of it in May and early June. Most males were mature at age 6 and most females at age 7. Fifty percent of the males and females were mature at 21 and 25 cm respectively. The growth rates of the males and females were similar until the age of 8, after which the females apparently outgrew the males. Early growth and fecundity were similar to those reported for other areas. No feeding took place in December or January but the flounder fed in March and continued to feed throughout the summer; food intake decreased in the fall. They were omnivorous and the type of food eaten varied with the locality. Polychaetes, plant material, and molluscs were the most common food items throughout the year. Capelin eggs and fish remains were found only during a few months of the year but were eaten in great quantities.

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