Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- A comparative study of the feeding ecology of Nephrops norvegicus (L.), (Decapoda : Nephropidae) in the bathyal Mediterranean and the adjacent AtlanticPublication . Cristo, Margarida; Cartes, JEA comparative study of the feeding ecology of Nephrops norvegicus was carried out on a seasonal basis simultaneously in seven locations in the Eastern and Western Mediterranean and the adjacent Atlantic: the south coast of Portugal, Fare; the Alboran Sea, Malaga; the Catalan Sea, Barcelona; the Ligurian Sea, Genoa; the Tyrrhenian Sea, Pisa: the Adriatic Sea, Ancona and the Aegean Sea, Gulf of Euboikos. The major groups observed (frequency of occurrence method) in the stomachs of Nephrops norvegicus were decapod crustaceans, other crustaceans (euphausids and peracarids) and fish. The results obtained showed no significant differences between sites or seasons, and can be considered very consistent. All major taxa were present in the diet at all sites and for all seasons, a fact that can be explained by the great similarity of the bathyal fauna in all sites, which provide a major trophic resource for N. norvegicus. The percentage of full ness was also estimated per site and season, and we registered a clear decrease of this value during the summer period for all sites, except the Tyrrheanian Sea, where the lowest value was found in autumn. PCA - analysis did not clearly separate the regions (sites). The Shannon-Weaver (H'), index of diversity, was also determined per site and season, and we found a significant difference between the values of the Atlantic coast and the Western Mediterranean when compared with those of the Eastern Mediterranean.
- Gut evacuation rates in Nephrops norvegicus (L., 1758): laboratory and field estimatesPublication . Cristo, MargaridaEstimates of gut evacuation rates of Nephrops norvegicus (Linnaeus, 1758) (Crustacea, Decapoda) were obtained during laboratory and field experiments. Individuals were collected off the south coast of Portugal in December 1997 and July 1998. Gut evacuation rates (R.h(-1)) were calculated from the slope of the regression of the natural logarithm of dry stomach content weight versus time, using data obtained by the "serial slaughter method". The values obtained during laboratory (R = 0.172 h(-1)) and field experiments (R = 0.177 h(-1)) are compared with gut evacuation rates reported for other marine organisms. The results obtained for both experiments are within the range of the values in the literature, even in the case in which different methodologies were used.