Alteração da comunidade zooplanctônica do saco dos Limões após impacto das obras da via expressa sul - baía sul da ilha de Santa Catarina

. In order to solve traffic problems in the capital, the government of the Santa Catarina State began in 1996 dredging works and hydraulic embankment in the “Saco dos Limões”, south bay of Santa Catarina Island. Studies of environmental impact accomplished by CTTMar (1996/1997) verified that the dredging activities altered the community of the local zooplankton. The present work studied the zooplankton community 6 years after the end of the dredging activities, diagnosing the possible alterations in the environment. The zooplankton samples were obtained between 1996 and 1998 (Phase 1, impact) and from 1999 to 2002 (Phase 2, after impact) by superficial hauls using a net WP-2 type with 200 mm of mesh size. The community’s typical species found were the copepods Acartia lilljeborgi, A. tonsa, Oithona oswaldocruzii and Paracalanus quasimodo. Among the two phases a significant decline was observed in the density of the zooplankton. A. tonsa, typical estuarine copepod was substituted by A. lilljeborgi inside of the bay. The same was observed for P. quasimodo that substituted O. oswaldocruzii in the intern area. These results suggest the hydrological changes in function of the increase of the depth, decrease of the area and the residence time of the water, impeding the development of estuarine community that was characteristic before the dredging and hydraulic embankment activities.. In order to solve traffic problems in the capital, the government of the Santa Catarina State began in 1996 dredging works and hydraulic embankment in the “Saco dos Limões”, south bay of Santa Catarina Island. Studies of environmental impact accomplished by CTTMar (1996/1997) verified that the dredging activities altered the community of the local zooplankton. The present work studied the zooplankton community 6 years after the end of the dredging activities, diagnosing the possible alterations in the environment. The zooplankton samples were obtained between 1996 and 1998 (Phase 1, impact) and from 1999 to 2002 (Phase 2, after impact) by superficial hauls using a net WP-2 type with 200 mm of mesh size. The community’s typical species found were the copepods Acartia lilljeborgi, A. tonsa, Oithona oswaldocruzii and Paracalanus quasimodo. Among the two phases a significant decline was observed in the density of the zooplankton. A. tonsa, typical estuarine copepod was substituted by A. lilljeborgi inside of the bay. The same was observed for P. quasimodo that substituted O. oswaldocruzii in the intern area. These results suggest the hydrological changes in function of the increase of the depth, decrease of the area and the residence time of the water, impeding the development of estuarine community that was characteristic before the dredging and hydraulic embankment activities

VARIABILIDADE NAS TAXAS FISIOLÓGICAS DO MEXILHÃO PERNA PERNA EM DOIS SÍTIOS DE CULTIVO DO LITORAL NORTE DE SANTA CATARINA

With the growing socioeconomic activity of mussel farming on Santa Catarina’s coast, the identification of new cultivation sites became necessary. Among a variety of methods used for the analysis of potential producing areas, studying of the mussel physiological rates may be considered as one of the most appropriated, specially when addressing the monitoring of sites already established and the negative effects of environmental pollution. This report presents a preliminary comparison between two areas of cultivation in the northern coast of the state (municipalities of Penha and Bombinhas). In both locations, environmental data (temperature, salinity and seston) and physiological parameters of the mussels (growth, and filtration, respiration and assimilation rates) were analysed. Our findings suggested a direct relationship between temperature and mussel growth rate and also between salinity and respiration rates for both areas. The seston concentration showed a high environmental variability as a response to the continental drainage. In addition, the filtration and assimilation rates seemed to be influenced by the stages of embryonic follicle maturation. In terms of production, the sites showed larger differences during the colder months as compared to the warmer ones, when the results were quite similar. More conclusive results are dependent of studies conducted along a complete annual cycle.Com a crescente atividade sócio-econômica da mitilicultura na costa do estado de Santa Catarina, problemas relacionados com a identificação de novos sítios de cultivo tornaram-se prioritários. Dentre os mais diferentes métodos utilizados para análise de potenciais regiões produtoras, o estudo das taxas fisiológicas dos mexilhões enquadram-se como uma das mais adequadas, incluindo neste caso, o monitoramento de sítios já estabelecidos e problemas relacionados com a poluição ambiental. Este relatório faz referência a uma preliminar comparação entre duas áreas de cultivo do mexilhão Perna perna no litoral norte do estado (municípios de Penha e Bombinhas). Dados ambientais de temperatura, salinidade, material em suspensão e fisiológicos do mexilhão como crescimento, filtração, respiração e assimilação foram comparados. Os principais resultados deste estudo podem ser resumidos em: relação direta entre a temperatura e a taxa de crescimento e relação entre a salinidade e a taxa de respiração para os dois ambientes. O material em suspensão apresentou uma maior variabilidade ambiental influenciada pelos aportes continentais mas que necessitam de maiores investigações. A importância das taxas de maturação dos folículos embrionários dos mexilhões foi sugerida na relação com as taxas de filtração e assimilação. Em termos de produção, os ambientes mostraram maiores diferenças nos meses frios e similar resultados nos meses quentes. Entretanto, resultados conclusivos estão dependentes de estudos ao longo de um ciclo anual