Author(s): Cartaxana, Maria Alexandra Sousa Dias, 1960-
Date: 2014
Persistent ID: http://hdl.handle.net/10451/15958
Origin: Repositório da Universidade de Lisboa
Subject(s): Ecologia marinha; Crustáceos; Palaemon longirostris; Habitat; Reprodução animal; Migração animal; Rio Mira (Portugal); Teses de doutoramento - 2014
Tese de doutoramento, Biologia (Ecografia), Universidade de Lisboa, Faculdade de Ciências, 2014
The white prawn, Palaemon longirostris H.-M. Edwards, 1837, is a shallow-water species, spread over a wide geographical area. Has been recorded in estuaries from the north of Africa up to western Germany and northeast of England and more recently its presence was registered for the Black Sea. Authors have disagreed on the taxonomic status of the white prawns over their distributional range that has been identified either as Palaemon longirostris and P.garciacidi. The present study compares variation in morphology and mtDNA in populations from the United Kingdom, the Netherlands, France, Spain, Portugal, Morocco and Tunisia. Findings from this study do not support the distinction of P.longirostris and P.garciacidi as different species. This study also aims at contributing to the knowledge of the bioecology of the prawn P.longirostris. The estuarine distribution of prawns of the River Mira population follow the salinity displacement, the animals being found at river stations during summer and autumn when saline encroachment up the estuary was greater. During winter and spring when freshwater input from the river was greatest, and thus moving the salinity gradient toward the mouth, the prawns migrated downstream to brackish areas. Ovigerous females were collected only from estuarine areas (January to August), suggesting that these population displacements are related to reproduction that does not take place in freshwater habitats. The reproductive period varies among the populations along their distributional range, starting earlier and being longer in the southern estuaries, probably due to the water higher temperature. The reproductive traits, fecundity, egg loss and size at maturity of female P.longirostris were also examined in this study. The growth was also studied for the Mira River population. This work contributes to a better understanding of morphological variation, migration patterns, reproduction and growth of P.longirostris, which can be used to implement a management and conservation measures that still lacking. It is urgent to develop management measures for the protection of the white shrimp, P.longirostris in estuaries and rivers over their distributional range, and the first efforts to be made should focus on habitat preservation and its rehabilitation by reinstating, for example, the longitudinal continuity of rivers allowing the reproductive migrations to take place.
Fundação para a Ciência e a tecnologia, IP (FCT)
