Seasonal changes in the distribution and abundance of marine cladocerans of the Northwest Alboran Sea (Western Mediterranean), Spain

The annual cycle of marine cladocerans was studied over six years from 1994 to 1999 within the frame of the monitoring Project ECOMALAGA at a nine stations in the NW of the Alboran Sea, with the aim of assessing seasonal patterns and interannual trends in distribution and abundance of marine cladocerans. Seven species (Penilia avirostris, Evadne nordmanni, Evadne spinifera, Pseudoevadne tergestina, Pleopis polyphemoides, Podon leuckarti and Podon intermedius) were detected in the northwest Alboran Sea. Total cladoceran relative abundance varied from 0 to 89 percent of the total cladocerans. The abundance of cladocerans was higher in summer-autumn than in winter-spring (7012 - 4711.100 and 743 - 217.100m-3 , respectively). The species composition was very different in terms of seasonality. P. polyphemoides, P. leuckarti and P. intermedius appeared mostly during the spring. P. tergestina, E. spinifera and E. nordmanni predominantly occurred during the winter. P. avirostris occurred mostly during the summer and autumn.

Distribution and abundance of carangidae (Teleostei, Perciformes) associated with oceanographic factors along the northeast brazilian exclusive economic zone

This work had as objective to study the distribution and abundance of the Carangidae larvae and to analyze the influence of the hydrological (temperature and salinity) and biological factors (phytoplanktonic biomass and zooplanktonic biomass), on the space and temporal distribution of the larvae. Ichthyoplankton was collected during four expeditions from the Northeast Exclusive Economic Zone. Six species (Trachurus lathami, Decapterus punctatus, Chloroscombrus chrysurus, Selene setapinnis, Selene vomer and Elagatis bipinnulata) and Caranx- Carangoides complex were identified. D. punctatus was the species most abundant (52 percent of the total), with higher abundance during the Period 3, while the Period 2 was the period of low abundance. C. chrysurus was the second species in abundance representing 30 percent of the total of carangid. This species had higher abundance during the Period 2 and the Period 1. However, in Period 3 abundance were lesser. The third species in abundance was T. lathami that corresponded 8 percent of the total of carangid larvae. S. setapinnis, S. vomer and E. bipinnulata were the species less abundant, representing together 2 percent of the total identified larvae. The larvae of Caranx- Carangoides complex represented 9 percent of the carangid total.

Este trabalho teve como objetivo estudar a distribuição e abundância das larvas de Carangidae, foi analisada também a influência de fatores hidrológicos (temperatura e salinidade) e biológicos (biomassa fitoplanctônica e biomassa zooplanctônica), sobre a distribuição espacial e temporal dessas larvas. O ictioplâncton foi coletado durante quatro expedições: Período 1 (Agosto Outubro 1995), Período 2 (Janeiro Abril 1997), Período 3 (Abril Julho 1998) e Período 4 (Setembro Dezembro 2000)), realizadas na Zona Econômica Exclusiva do nordeste. Em um total de 313 larvas foram identificadas 6 espécies (Trachurus lathami, Decapterus punctatus, Chloroscombrus chrysurus, Selene setapinnis, Selene vomer e Elagatis bipinnulata) e o Complexo Caranx Carangoides pertencentes à família Carangidae. D. punctatus foi a espécie mais abundante neste estudo (52 por cento do total). Sua maior abundância foi observada no Período 3 e a menor no Período 2. C. chrysurus foi a segunda espécie em abundância representando 30 por cento do total de carangídeos. Esta espécie teve maior abundância durante o Período 2, enquanto que os Períodos 1 e 3 foram ás épocas de menor abundância. A terceira espécie em abundância foi T. lathami que correspondeu 8 por cento do total de larvas de carangídeos, sendo o Período 4 o mais abundante. S. setapinnis, S. vomer e E. bipinnulata foram bem menos abundantes que as outras espécies analisadas, representando juntas 2 por cento do total de larvas identificadas. Larvas do Complexo Caranx - Carangoides representaram 9 por cento do total de carangídeos.