Population structure and species dynamics of Spisula solida, Diogenes pugilator...

• Author(s): Dolbeth, M. ; Viegas, I. ; Martinho, F. ; Marques, J. C. ; Pardal, M. A.
• Date: 2006
• Persistent ID: http://hdl.handle.net/10316/13097
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Spisula solida; Diogenes pugilator; Branchiostoma lanceolatum; Population dynamics; Hydrodynamics; Fisheries
• Document Type: Article
• Language: English

Description

The population structure, dynamics and distribution of Spisula solida, Diogenes pugilator and Branchiostoma lanceolatum, common species in the south coast of Portugal, were studied in a spatial–temporal manner in order to understand the influence of cross-shore sediment transport and anthropogenic activities. Spisula solida is harvested commercially, whereas D. pugilator and B. lanceolatum are non-target species, with little information available on the population dynamics of these species. The study was performed in 2001–2002, and along a gradient of 100–5000 m from the coastline, corresponding to a depth gradient of between 1 and 32 m deep. Spisula solida was distributed preferentially at 3–12 m deep, and its distribution appeared to be influenced seasonally by the cross-shore sediment dynamics. Results suggested benthic recruitment in June. Some recruitments had no expression (year 2001) since adults were not present, which seems to be a direct impact of clams' fisheries. Diogenes pugilator showed preferential distribution at shallow depths, from 1.3 to 8 m. Results suggested recruitments every 4 months, in June, February and October. Branchiostoma lanceolatum showed the widest distribution, from 7 to 26 m deep. Recruitment seemed to start in June until October, when it attained an abundance peak of juveniles. For both non-target species no clear effects of the cross-shore dynamics or the clams' fisheries impact were visible http://dx.doi.org/10.1016/j.ecss.2005.08.006