Secondary production of Jassa slatteryi (Amphipoda, Ischyroceridae) on a Zostera marina seagrass bed in southern Korea

Abstract

On the basis of monthly samples, we measured the secondary production of the amphi- pod Jassa slatteryi Conlan 1990, on a Zostera marina L. seagrass bed in Gwangyang Bay, southern Korea. The standing crop of seagrass showed 2 peaks in spring and fall, with maximum biomass in May. Biomass distribution of J. slatteryi was positively correlated with the standing crop of seagrass (p < 0.05), suggesting that there is a biological interaction between these 2 species. J. slatteryi dis- plays 2 main breeding periods during the year; in spring (March to May) and in fall (October to December). The biomass of J. slatteryi and the standing crop of seagrass in the spring was much higher than in the fall. The annual secondary production of J. slatteryi in the Gwangyang Bay sea- grass bed (20.07 g dry weight m -2 yr -1 ) is the highest reported in amphipods inhabiting seagrass beds. However, the annual production:biomass (P:B) ratio, at 5.21, was lower than recorded previously in both temperate and tropical seagrass beds because the number of generations decreases the P:B ratio. The combination of high abundance and secondary production suggests an important role for J. slatteryi in the seagrass-bed ecosystem as a trophic link from primary producers to higher con- sumers.