Kj. Hartman et Sb. Brandt, PREDATORY DEMAND AND IMPACT OF STRIPED BASS, BLUEFISH, AND WEAKFISH IN THE CHESAPEAKE-BAY - APPLICATIONS OF BIOENERGETICS MODELS, Canadian journal of fisheries and aquatic sciences, 52(8), 1995, pp. 1667-1687
We applied bioenergetics models for dominant Chesapeake Bay piscivores
, striped bass (Morone saxatilis), bluefish (Pomatomus saltatrix), and
weakfish (Cynoscion regalis), along with site-specific data on diets,
growth, and energy density, to examine trophic linkages and the relat
ionship of predatory demand to prey supply. Atlantic menhaden (Brevoor
tia tyrannus), bay anchovy (Anchoa mitchilli), and spot (Leiostomus xa
nthurus) accounted for 65-99% of the annual biomass of piscivore diets
(excluding age-0 striped bass that ate mostly invertebrates). The die
ts of young piscivores were dominated by anchovy, but menhaden and spo
t became increasingly important to older fish. Young (age < 2) striped
bass ate mostly benthic prey. Older striped bass fed increasingly on
pelagic sources, primarily menhaden, but bluefish and weakfish increas
ed benthic resource use from 10% at age 0 to 50% by age 2. Comparison
of consumption (supply) to demand (potential consumption) measured the
suitability of Chesapeake Bay for predator production. Bluefish came
closest to achieving their demand for prey, suggesting that they are m
ore successful predators than either striped bass or weakfish. Results
suggest that Chesapeake Bay may be a better nursery than production a
rea for older fish, and prey supply (not temperature) may account for
the movements and use of the estuary by older piscivores.