Document details

Connectivity between tropical coastal habitats:using stable isotopes in juvenil...

Author(s): Abreu, Daniela Carvalho de, 1990- cv logo 1

Date: 2008

Persistent ID: http://hdl.handle.net/10451/1223

Origin: Repositório da Universidade de Lisboa

Subject(s): Crustáceos; Ecossistemas aquáticos; Mangal; Teses de mestrado


Description
Tese de mestrado, Biologia (Biologia e Gestão de Recursos Marinhos), 2008, Universidade de Lisboa, Faculdade de Ciências Mangroves and its adjacent coastal systems such as seagrass meadows, muddy and sandy habitats are well known as nurseries areas for numerous species, particularly penaeid shrimps, one of the most important fishery resources in the world. Spatial and temporal coastal habitat utilization by individuals of different species is often associated to the food availability and protection against predators that each habitat may provide. A better understanding on the coastal habitats use as refuge and feeding ground for a variety of species and their movement between and across habitats is extremely important to elucidate the connectivity between the habitats which therefore is extremely important information for the preparation of conservation and management plans of the fishery resources and their habitats. Making use of carbon and nitrogen stable isotope analysis, the present study, conducted at Inhaca Island (south of Mozambique) in two mangrove fringed bays (Saco and Sangala Bays), intended to investigate the biological connectivity within the mangrove and its adjacent coastal habitats (sand flat, mud flat and seagrass meadows) in terms of feeding areas for four of the most commercially important penaeid shrimps species in Mozambique (Metapenaeus monoceros, M. stebbingi, Marsupenaeus japonicus and Fenneropenaeus indicus). Different potential food sources (mangrove leaves, seagrass leaves, epiphytic algae on the mangrove roots and on seagrass leaves, benthic microalgae, plankton, polychaetes, isopods and sediment detritus) had been collected and analyzed for each habitat and compared to shrimp species carbon and nitrogen isotope ratio. Significant differences (p < 0.05) were observed on carbon and nitrogen isotope ratios among potential food sources in each habitat on both Saco and Sangala Bays (composing an important tool for habitat discrimination) and also observed for carbon and nitrogen isotope ratios between shrimp species among the different habitats. Mangrove and seagrasses do not seem to be a direct food source for penaeid shrimps at Saco and Sangala Bays, but the seagrasses epiphytic algae, benthic microalgae, sediment detritus, polychaetes and plankton are the most likely potential food sources. No ontogenetic dietary shifts were reported for the penaeid shrimp species on the present study. It appears to exist a habitat connectivity related to feeding for all the shrimp species on both bays, which could be a result of tidal migration or even from a recent migration for a new habitat seeking for better protection. The mud and sand flat and the seagrass habitats are used as feeding area by shrimp species at Saco Bay and the sand flat and seagrass habitats are used as feeding areas at Sangala Bay Resumo alargado disponível em português
Document Type Master Thesis
Advisor(s) Paula, José Pavão Mendes de, 1959-; Macia, Adriano
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