Growth and Production of Pholis nebulosa (Temminck & Schlegel, 1845) in a Seagrass (Zostera marina) Bed of Southern Korea

Abstract

The seagrass habitats are a highly productive marine ecosystem which provides nursery ground and shelter for many fish and invertebrate species. Pholis nebulosa (Temminck & Schlegel, 1845) is one of the most abundant seagrass fishes in the coastal waters of Korea. The estimation of fish production is key for devising conservation measures and ensuring fish resources sustainability. A total 894 P. nebulosa ranging from 3.83 to 26.5 cm total length (TL) were collected monthly in 2006 with a small beam trawl in a seagrass bed of southern Korea. Growth parameters of P. nebulosa were estimated using the von Bertalanffy growth model, and production was estimated using a general equation which relates daily fish production to ash-free dry weight (AFDW), biomass, and water temperature. The von Bertalanffy's growth equation was estimated as: Lt = 28.3823(1-e-0.7835(t+0.9864)). The densities, biomass, daily, annual production, and P/B ratio were 0.069±0.061/m-2, 1.022±0.621 g/m2, 0.005±0.004 g AFDW/m2/day , 1.676 g A FDW/m2/yr, and 1.641, respectively. Monthly variation in production of P. nebulosa peaked during March and April 2006 (0.0139 and 0.0111 g AFDW/m2/day), whereas the lowest value of 0.0005 g AFDW/m2/day was in December. Monthly change in production of P. nebulosa was positively correlated with biomass and condition factor. Our results will contribute to the conservation of seagrass ecosystems, which are still undisturbed in the study area.