Bay anchovy Anchoa mitchilli production and consumption in mid- Chesapeake Bay based on a bioenergetics model and acoustic measures of fish abundance

Abstract

In model simulations, bay anchovy grew 3-6% d-1 during summer and fall, and young-of-the-year (YOY) bay anchovy biomass peaked in November (16 270 kg km-2). Weight-specific consumption rate of juvenile bay anchovy was 60% d-1 during summer, and population consumption peaked in September (3350 kg km-2 d-1). Population production rate of YOY also peaked in September at 290 kg km-2 d-1, and annual production was 30 770 kg km-2. If all mortality was due to predation, bay anchovy could provide 133 kg food km-2 d-1 for piscivores in November, which could support the maximum daily consumption of 13 300 age-2 striped bass Morone saxatilis per km2. Average trophic efficiency of bay anchovy was 10.7% with a large seasonal variation (0-18%). Sensitivity analyses identified that weight and temperature-specific consumption and respiration parameters were most sensitive in model simulations of fish growth. Compared with the estimated zooplankton production, the average bay anchovy consumption only accounted for a small portion of daily zooplantkton production. But the spatially-explicit model indicated that local depletions of zooplankton were possible due to spatial patchiness of predator and habitat heterogeneity, particularly in July. -from Authors