Population dynamics and secondary production of a key benthic tanaidacean, Monokalliapseudes schubarti (Mañé-Garzón, 1949) (Tanaidacea, Kalliapseudidae), from a tropical coastal lagoon in southeastern Brazil

Abstract

Estimates of population dynamics and secondary production are important to understand the role of species in ecosystems and the mechanisms that drive life-history trade-offs, contributing to system preservation and monitoring. Population dynamics (growth rate, instantaneous mortality rates and longevity) and secondary production (biomass, production and P/B ratio) of the key marine benthic species Monokalliapseudes schubarti (Mañé-Garzón, 1949) were investigated monthly in a tropical coastal lagoon over 18 months and compared with data from other subtropical and temperate populations. A growth curve was estimated by fitting the Von Bertalanffy growth model. M. schubarti showed latitudinal variation in growth parameters. In tropical areas, M. schubarti generated consecutive cohorts and the growth curve parameters were: , , . A smaller asymptotic length was found for tropical and subtropical areas compared with data from temperate areas, and a lower growth rate was found at the tropical site. The annual mortality rate for the finite population was 0.999 year−1. Longevity, estimated at 10 months, was lower at the tropical site. The secondary production rate of M. schubarti at the tropical coastal lagoon was 10.60 g AFDW m−2 year−1, with a P/B ratio = 5.44. Brief longevity, a high P/B ratio, and high mortality may indicate M. schubarti as an opportunistic species in tropical areas.