Trophic transfer in seagrass systems: estimating seasonal production of an abundant seagrass fish, Bairdiella chrysoura, in lower Chesapeake Bay

Abstract

Silver perch Bairdiella chrysoura is a seasonally abundant fish in lower Chesapeake Bay seagrass habitats. Young-of-the-year fish recruit to these habitats in June and rear for the remainder of the summer before migrating to deeper habitats in the Bay and offshore as seawater cools in the fall. This species has been shown to be abundant in seagrass habitats, yet like many fishes in these habitats, little is known about its growth and production, and thus the contribution of this habitat type to overall production. We developed a bioenergetics model to estimate individual silver perch growth and calibrated this model using field-collected size data. Abundance data were used to develop a generalized additive model for predicting abundance over the simulation period (15 June to 15 October). We used the individual-based model output and estimated abundances to calculate total production. The calibrated bioenergetics model showed silver perch growth of approximately 0.19 g d −1 for total growth of 23.2 g over the simulation period. Peak abundance occurred in July with estimated values of 0.2 ind. m −2. The highest biomass was observed shortly after peak abundance. Total production for silver perch was estimated to be 22.9 g m −2 in the seagrass habitats measured. With an estimated 8100 ha of seagrass habitat in the lower Chesapeake Bay in 2010, silver perch contribute a considerable amount of biomass production. As an annually migrating species, silver perch export in excess of 7400 t of biomass to the near-coastal ecosystem, providing a trophic subsidy from seagrass habitats via trophic transfer.

Multiple stressors threaten the imperiled coastal foundation species eelgrass (Zostera marina) in Chesapeake Bay,USA

“…This value represents 1–2 years of the fishery, and even then does not account for consequent losses in recruitment in subsequent years. Similarly, the expected loss of silver perch equates to 10–20 years of the fishery (Sobocinski & Latour, ).…”

“…This value represents 1-2 years of the fishery, and even then does not account for consequent losses in recruitment in subsequent years. Similarly, the expected loss of silver perch equates to 10-20 years of the fishery (Sobocinski & Latour, 2015). In all, an independent and integrated measure of economic valuation (Costanza et al, 2014) places the total potential economic loss due to the decline of eelgrass in Chesapeake Bay at $US 1.51-2.54 billion.…”

“…Estimates of silver perch production were obtained from (Sobocinski & Latour, 2015). We used a mean value of 91.5 g m À2 yr À1 , and obtained standard errors from the range 77.8-117.8 g m À2 yr À1 using the range rule, as above.…”

Multiple stressors threaten the imperiled coastal foundation species eelgrass (Zostera marina) in Chesapeake Bay, USA

“…This 316 value represents 1-2 years of the fishery, and even then does not account for consequent losses in 317 recruitment in subsequent years. Similarly, the expected loss of silver perch equates to 10-20 years 318 of the fishery (Sobocinski & Latour, 2015). 319…”

Untitled

“…These values were then averaged across all 229 months and years to produce a mean and standard errors. Estimates of silver perch production were obtained from (Sobocinski & Latour, 2015). We 240 used a mean value of 91.5 g m -2 y -1 , and obtained standard errors from the range 77.8-117.8 g m -2 y -241 1 using the range rule, as above.…”