Individual-Based Model of Young-of-the-Year Striped Bass Population Dynamics. I. Model Description and Baseline Simulations

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.

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TESTING A SPATIALLY EXPLICIT, INDIVIDUAL-BASED MODEL OF RED-COCKADED WOODPECKER POPULATION DYNAMICS

Ecological Applications ◽

10.1890/04-1473 ◽

2005 ◽

Vol 15 (5) ◽

pp. 1495-1503 ◽

Cited By ~ 12

Author(s):

Karin Schiegg ◽

Jeffrey R. Walters ◽

Jeffery A. Priddy

Keyword(s):

Population Dynamics ◽

Spatially Explicit ◽

Individual Based Model ◽

Red Cockaded Woodpecker

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-051 ◽

2002 ◽

Vol 59 (5) ◽

pp. 787-795 ◽

Cited By ~ 41

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·day1 to 1°C·week1) 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.

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Population Dynamics of an Estuarine-Dependent Fish, the Spot (Leiostomus xanthurus), ASong a Tidal Creek–Seagrass Meadow Coenocline

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-189 ◽

1983 ◽

Vol 40 (10) ◽

pp. 1633-1638 ◽

Cited By ~ 21

Author(s):

Michael P. Weinstein

Keyword(s):

Population Dynamics ◽

Decay Rate ◽

Turnover Rate ◽

Total Population ◽

Seagrass Meadow ◽

Tidal Creek ◽

Leiostomus Xanthurus ◽

Population Turnover ◽

Young Of The Year ◽

Average Individual

To study the population dynamics of young-of-the-year spot (Leiostomus xanthurus) I released 6981 marked fish midway up the tidal creek portion of a small (<20 ha) marsh creek–seagrass meadow coenocline. Holding mortality experiments (96 h) indicated that 61.5%, or 4300 individuals, survived the marking process to constitute the population available for recapture. Over a 90-d study period, 212 marked fishes were recaptured. From plots of the ratio of marked to unmarked individuals in subsequent samples, I concluded that the population was resident in the creek for up to 182 d with the average individual present for 91 d. When this population turnover rate was compared to the total population decay rate (marked plus unmarked fish), the exchange between habitats (immigration/emigration) accounted for about 26% of the total decay rate, with the remainder attributed to natural mortality. By correcting the overall disappearance rate for population turnover due to immigration/emigration, and using this adjusted value as a measure of instantaneous mortality (Z), the estimated production in this population was 21.8 kcal (91342 J)∙m−2∙d−1. This figure is over six times greater than previously reported values for this species for all size classes over the entire growing season.

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