Activity-related constraints on overwintering young-of-the-year striped bass (Morone saxatilis)

2001 ◽  
Vol 79 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Thomas P Hurst ◽  
David O Conover
Keyword(s):  
Food Consumption ◽  
Striped Bass ◽  
Morone Saxatilis ◽  
Metabolic Cost ◽  
Hudson River ◽  
Energetic Cost ◽  
Energy Budgets ◽  
Swimming Velocity ◽  
Thermal Dependence ◽  
Young Of The Year

The importance of activity to overwintering fishes has received little attention. Activity imposes two constraints: maximum swimming speed limits habitats that can be occupied for short periods of time, while the metabolic cost of swimming limits the habitats that are suitable for long-term residence. We measured the energetic consequences of activity and maximum swimming speeds of young-of-the-year striped bass (Morone saxatilis), a species that overwinters in tidal estuaries. The energetic cost of swimming was determined from energy changes in unfed fish forced to swim at various speeds, while energy changes in fed fish provided a measure of their ability to offset swimming costs through feeding. In high-velocity treatments, mortality was size-dependent and appeared to be related to fatigue rather than to depletion of energy reserves. The energetic cost of swimming increased with swimming velocity, but fish increased food consumption and thereby met their metabolic needs. In a second experiment the thermal dependence of swimming capacity in winter-acclimated striped bass was measured. Swimming speeds increased with temperature, from 2.7 body lengths (BL)/s at 2°C to 4.8 BL/s at 8 and 11°C, but were considerably below observed flow velocities in the Hudson River, suggesting a need for behavioral or physical refuge from tidal currents. These results indicate the flexibility of energy budgets of overwintering fishes, allowing energetic stress to be minimized by reducing activity or elevating food-consumption rates when sufficient prey are available.

Effects of temperature and salinity on survival of young-of-the-year Hudson River striped bass (Morone saxatilis): implications for optimal overwintering habitats

2002 ◽  
Vol 59 (5) ◽  
pp. 787-795 ◽  
Author(s):  
Thomas P Hurst ◽  
David O Conover
Keyword(s):  
Body Size ◽  
Low Temperature ◽  
Striped Bass ◽  
Low Temperatures ◽  
Morone Saxatilis ◽  
Hudson River ◽  
Temperature Tolerance ◽  
Low Temperature Tolerance ◽  
Energetic State ◽  
Young Of The Year

We examined the role of salinity, body size, and energetic state in determining low temperature tolerance of young-of-the-year (YOY) striped bass (Morone saxatilis) and used this information to map optimal overwintering habitat in the Hudson River estuary. A long-term experiment compared survival at 15 ppt and 30 ppt. In additional experiments, winter-acclimated fish were exposed to temperature declines (2.3°C·day–1 to 1°C·week–1) at salinities from 0 ppt to 35 ppt. Highest survival at low temperatures was consistently observed at intermediate salinities. These results suggest that the observed distribution of overwintering striped bass is related to physiological constraints on osmo regulatory ability at low temperatures. Low temperature tolerance appeared unrelated to body size and energetic state. Salinity profiles were used to describe the location and extent of optimal wintering habitats under various hydrographic regimes. The location of optimal habitats was displaced by over 27 km along the river axis because of variation in salinity regime. Changes in the availability of optimal habitat may be responsible for variation in recruitment to the Hudson River population. These results demonstrate the need to consider a holistic approach encompassing all seasons of the year in assessing habitat requirements of fishes.

Winter mortality of young-of-the-year Hudson River striped bass (Morone saxatilis): size-dependent patterns and effects on recruitment

1998 ◽  
Vol 55 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Thomas P Hurst ◽  
David O Conover
Keyword(s):  
Striped Bass ◽  
Morone Saxatilis ◽  
Hudson River ◽  
Progressive Increase ◽  
Winter Mortality ◽  
Ambient Conditions ◽  
Catch Per Unit Effort ◽  
Size Dependent ◽  
Class Strength ◽  
Young Of The Year

Winter mortality plays a significant role in the dynamics of some temperate fish populations and has been shown to be size-dependent for some species, but not for others. Our objective was to determine how winter mortality affects the recruitment dynamics of Hudson River striped bass (Morone saxatilis). We used catch-per-unit-effort data from three separate surveys targeting young-of-the-year (YOY), overwintering, and age 1 striped bass. Age 1 abundance was negatively correlated with the severity of winter. In contrast, the abundance of age 0 fish was not correlated with age 1 abundance, suggesting that winter mortality greatly modifies year-class strength. A progressive increase in the mean length of YOY fish, coupled with a decrease in the coefficient of variation in length, occurred during some winters. Laboratory experiments showed that growth in length requires temperatures in excess of 10°C; hence, these changes likely result from selective mortality of smaller fish. Direct evidence of size-dependent mortality was obtained from a laboratory experiment that exposed fish to ambient conditions throughout the winter. Accounting for interannual differences in the severity and size dependency of winter mortality may improve our ability to evaluate striped bass year-class strength in the Hudson River.

Optimum Exercise Conditioning Velocity for Growth, Muscular Development, and Swimming Performance in Young-of-the-Year Striped Bass (Morone saxatilis)

1994 ◽  
Vol 51 (7) ◽  
pp. 1519-1527 ◽  
Author(s):  
Paciencia S. Young ◽  
Joseph J. Cech Jr.
Keyword(s):  
Striped Bass ◽  
White Muscle ◽  
Swimming Performance ◽  
Morone Saxatilis ◽  
Swimming Velocity ◽  
Natural Ecosystems ◽  
Cross Sectional ◽  
Muscular Development ◽  
Conditioning Period ◽  
Young Of The Year

Young-of-the-year striped bass (Morone saxatilis) were exercise conditioned for 60 d at four different water velocities: <0.02 (control), 0.5–1.2 (slow), 1.5–2.4 (moderate), and 2.4–3.6 body lengths∙s−1 (fast). Sampling for growth (body weight change), muscular development (red and white muscle cross-sectional areas), and swimming performance (critical swimming velocity) was done at 50 and 60 d of the exercise conditioning period and at 14, 28, 42, and 56 d post-conditioning. Optimum conditioning velocities for growth and swimming performance were the moderate and fast velocities, respectively, with both effects persisting 56 d post-conditioning. Fish exercised at the moderate and fast velocities showed significant increases in red muscle areas (at 0 and 14 d post-conditioning, respectively) and in white muscle areas (at 0–28 and 14–28 d post-conditioning, respectively). Exercise-conditioned fish at any velocity showed a significant increase in the red to white muscle ratio at the end of 60 d of conditioning. Our data suggest that exercise-conditioned young-of-the-year striped bass would have size and swimming advantages consistent with higher survival than unexercised fish when stocked in natural ecosystems.

Dispersal of Young-of-the-Year Hatchery Striped Bass in the Hudson River

1991 ◽  
Vol 11 (3) ◽  
pp. 381-392 ◽  
Author(s):  
Alan W. Wells ◽  
Donna M. Randall ◽  
Dennis J. Dunning ◽  
John R. Young
Keyword(s):  
Striped Bass ◽  
Hudson River ◽  
Young Of The Year

Comparison of Logistic Regression and Discriminant Analyses for Stock Identification of Anadromous Fish, with Application to Striped Bass (Morone saxatilis) and American Shad (Alosa sapidissima)

1990 ◽  
Vol 47 (8) ◽  
pp. 1570-1577 ◽  
Author(s):  
Michael H. Prager ◽  
Mary C. Fabrizio
Keyword(s):  
Logistic Regression ◽  
Striped Bass ◽  
Logistic Model ◽  
Morone Saxatilis ◽  
Hudson River ◽  
American Shad ◽  
Stock Identification ◽  
Connecticut River ◽  
Alosa Sapidissima ◽  
Discriminant Analyses

We examined the applicability of logistic regression to stock identification studies and compared its performance on two data sets to that of linear and quadratic discriminant functions. Logistic regression can be used to model a categorical dependent variable associated with continuous or discrete independent variables, and is preferred to discriminant analyses when the explanatory variables are not multivariate normal. Our examples were American shad (Alosa sapidissima) from the Connecticut River and Hudson River estuaries, and striped bass (Morone Saxatilis) from the Hudson River, Chesapeake Bay, and Roanoke River estuaries. In the examples we used a resampling method to assess classification and allocation errors of the two methods on new data. For the shad data, the logistic model classified significantly more fish correctly, and provided a significantly better estimate of stock composition. For the striped bass data, the two methods classified about the same proportion of fish correctly, but the logistic model gave a significantly better estimate of stock composition.

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