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.

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.

Selective Exploitation of Capelin (Mallotus villosus) Eggs by Winter Flounder (Pseudopleuronectes americanus): Capelin Egg Mortality Rates, and Contribution of Egg Energy to the Annual Growth of Flounder

1984 ◽  
Vol 41 (9) ◽  
pp. 1294-1302 ◽  
Author(s):  
K. T. Frank ◽  
W. C. Leggett
Keyword(s):  
Average Energy ◽  
Winter Flounder ◽  
Annual Growth ◽  
Pseudopleuronectes Americanus ◽  
Mallotus Villosus ◽  
Egg Mortality ◽  
Capelin Mallotus Villosus ◽  
Gonad Production ◽  
Conception Bay ◽  
Spawning Sites

The consequences of winter flounder (Pseudopleuronectes americanus) predation on capelin (Mallotus villosus) eggs, both in terms of the egg mortality and of the contribution of energy ingested to the annual growth of flounder, were investigated at Bryant's Cove, Conception Bay, Newfoundland. Flounder density in the nearshore area adjacent to the capelin spawning beach increased sharply in each of the three study years in response to the presence of spawning capelin and to the density of capelin eggs on the spawning beaches. Capelin eggs were the dominant item inthedietofwinterflounder14–34 cm TL, averaging 59% by weight. Flounder [Formula: see text] fed less heavily on capelin eggs (22% of food consumed by weight) but because of their larger size and ration were an important source of predation. Egg mortality due to flounder predation was estimated to average 5.0, 2.2, and 1.9% in 1978, 1979, and 1980, respectively. Egg mortality due to predation is believed to be significantly greater at deepwater demersal spawning sites and may have a significant impact on recruitment in demersal spawners. The average energy gain to winter flounder resulting from consumption of capelin eggs was estimated to contribute 23% of the annual growth of flounder in the region (approximate 95% confidence interval: 10–40%). Selective exploitation of capelin eggs by postspawning flounder may also contribute significantly to the rapid recovery of body condition following the extensive depletion of tissue resources due to winter fasting, gonad production, and spawning.

Chlorinated Hydrocarbon Insecticide Residues in Winter Flounder, Pseudopleuronectes americanus, from the Weweantic River Estuary, Massachusetts

1970 ◽  
Vol 27 (12) ◽  
pp. 2374-2380 ◽  
Author(s):  
Roderick M. Smith ◽  
Charles F. Cole
Keyword(s):  
Adult Female ◽  
River Estuary ◽  
Winter Flounder ◽  
Spawning Season ◽  
Heptachlor Epoxide ◽  
Pseudopleuronectes Americanus ◽  
Chlorinated Hydrocarbon ◽  
Insecticide Residues ◽  
High Runoff

Residues of DDT, heptachlor, and dieldrin were found in tissues of winter flounder, Pseudopleuronectes americanus (Walbaum), from the Weweantic River estuary, Massachusetts during 1966–67. In nonmigratory juveniles, seasonal accumulation patterns were demonstrated for DDT, heptachlor, and two related breakdown products, DDE and heptachlor epoxide. Peak concentrations of the parent compounds were more closely associated with high runoff conditions than any specific application in the estuarine drainage. Dieldrin was present uniformly throughout the year.Migratory adult flounder, present only between October and May, contained heptachlor and heptachlor epoxide levels similar to juveniles, but significantly less DDE. Adult female flounder sequentially concentrated DDT, DDE, and heptachlor epoxide in their ripening ovaries as the spawning season approached.

A temperature- and size-dependent model of sand shrimp (Crangon septemspinosa) predation on juvenile winter flounder (Pseudopleuronectes americanus)

2003 ◽  
Vol 60 (9) ◽  
pp. 1133-1148 ◽  
Author(s):  
David L Taylor ◽  
Jeremy S Collie
Keyword(s):  
Extreme Temperature ◽  
Winter Flounder ◽  
Interannual Variations ◽  
Pseudopleuronectes Americanus ◽  
Somatic Development ◽  
Size Dependent ◽  
Model Predictions ◽  
Dependent Model ◽  
Crangon Septemspinosa ◽  
Temporal Overlap

We investigated the temperature-mediated vulnerability of postsettled winter flounder (Pseudopleuronectes americanus) to sand shrimp (Crangon septemspinosa) predation. Small increases in flounder growth rates substantially decreased predator-induced mortality. Recent warming trends in Northwest Atlantic estuaries can increase flounder survival by accelerating growth and minimizing the duration during which juveniles are susceptible to size-dependent predation. Extreme temperature increases, however, depress growth because a disproportionate amount of energy is devoted to increased metabolism, leaving less for somatic development. Flounder survival is also reduced during warm years because of intensified shrimp predation. Moreover, interannual variations in temperature affect the relative timing of shrimp migration and flounder settlement, thus controlling the spatial and temporal overlap between predator and prey. Predicted flounder abundance and survival were statistically unrelated to observed flounder abundance sampled annually during late spring. However, model predictions and field data suggest that flounder abundance is maximal in years when seasonally averaged temperature is approximately 16 °C. Above and below this temperature, flounder year-class size is considerably lower, possibly as a result of temperature effects on trophic dynamics. We conclude that shrimp predation is a significant source of mortality for postsettled flounder, but it is not the sole determinant of interannual variations in recruitment.

scholarly journals Effect of Temperature Conditions on Flame Evolutions of Turbulent Jet Ignition

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2226
Author(s):  
Jiaying Pan ◽  
Yu He ◽  
Tao Li ◽  
Haiqiao Wei ◽  
Lei Wang ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Early Stage ◽  
Turbulent Jet ◽  
Combustion Stability ◽  
Effect Of Temperature ◽  
Main Chamber ◽  
Detailed Chemical Kinetics ◽  
Jet Flame ◽  
Spherical Flame ◽  
Temperature Conditions

Turbulent jet ignition technology can significantly improve lean combustion stability and suppress engine knocking. However, the narrow jet channel between the pre-chamber and the main chamber leads to some difficulties in heat exchange, which significantly affects combustion performance and mechanical component lifetime. To clarify the effect of temperature conditions on combustion evolutions of turbulent jet ignition, direct numerical simulations with detailed chemical kinetics were employed under engine-relevant conditions. The flame propagation in the pre-chamber and the early-stage turbulent jet ignition in the main chamber were investigated. The results show that depending on temperature conditions, two types of flame configuration can be identified in the main chamber, i.e., the normal turbulent jet flame propagation and the spherical flame propagation, and the latter is closely associated with pressure wave disturbance. Under low-temperature conditions, the cold jet stoichiometric mixtures and the vortexes induced by the jet flow determine the early-stage flame development in the main chamber. Under intermediate temperature conditions, pre-flame heat release and leading pressure waves are induced in the jet channel, which can be regarded as a transition of different combustion modes. Whereas under high-temperature conditions, irregular auto-ignition events start to occur, and spherical flame fronts are induced in the main chamber, behaving faster flame propagation.

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