| Resumo: |
In this Thesis we presented the first steps in the study of the life history and population dynamics of Lychnorhiza lucerna as well as the possibilities of development of its fishery in Argentina. L. lucerna presented a metagenetic life cycle characteristic of most scyphozoans. Polyps reproduced asexually by the production of podocysts and polidisk strobilation. The combination of both types of asexual reproduction resulted in a high strobilation rates indicating that the abundance of medusae would strongly depend on polyps abundance and reproduction. The absence of ephyrae in the Río de la Plata estuary suggest that L. lucerna doest not complete its life cycle locally but medusae would be produced by polyps located northwards along the Uruguayan or Brazilian coasts. L. lucerna was capable of reproducing sexually as well as sexually within the summer range of temperature and salinity of the Río de la Plata estuary. However, this species could be limited by the availability of suitable substrates and the high sedimentation rates which would impede settlement of planulae and development of polyps. The occurrence of these medusae in the region was strongly seasonal and was restricted to the period between January and May. Highest abundances were reached among February and March at levels which could allow the development of a fishery. A product of intermediate quality. Nevertheless, the low cost of jellyfish processing techniques, the increasing demand of products from the consumer countries, and the economical needs of local fishermen, indicated that the development of a jellyfish fishery is possible in the future.
Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales
|
