The relationships between changes in demersal resources (in terms of density, biomass and median length) and anthropogenic and environmental variables (fishing effort, Sea Surface Temperature, precipitations, NAO and MO Indices) in the North-Western Ionian Sea were evaluated. Biological data were collected during ten trawl surveys carried out from 1995 to 2006 in the investigated area. The following commercial species, belonging to the faunistic category of crustaceans, were considered: Aristaeomorpha foliacea (Risso, 1816) and Parapenaeus longirostris (Lucas, 1846). GAM models were used to evaluated the spatio-temporal changes of deep-water rose shrimp, Parapenaeus longirostris. Instead, COstrained Zero-Inflated GAM’s (COZIGAM) were applied to the spatio-temporal case study concerning the red shrimp, due to the high proportion of zeros in the data of Aristaeomorpha foliacea. The study shows a significance of the spa- tial variability and of the temporal evolution of the abundance of the resources considered. While depth, fishing effort, rainfall and baric indices significantly influence the deep-water rose shrimp distribution, the red shrimp distribution is only influenced by baric indices NAO and MO.
(2012). Modeling spatio-temporal abundance data of the Ionian sea populations of two crustaceans species [working paper]. Retrieved from http://hdl.handle.net/10446/26478
Modeling spatio-temporal abundance data of the Ionian sea populations of two crustaceans species
2012-04-01
Abstract
The relationships between changes in demersal resources (in terms of density, biomass and median length) and anthropogenic and environmental variables (fishing effort, Sea Surface Temperature, precipitations, NAO and MO Indices) in the North-Western Ionian Sea were evaluated. Biological data were collected during ten trawl surveys carried out from 1995 to 2006 in the investigated area. The following commercial species, belonging to the faunistic category of crustaceans, were considered: Aristaeomorpha foliacea (Risso, 1816) and Parapenaeus longirostris (Lucas, 1846). GAM models were used to evaluated the spatio-temporal changes of deep-water rose shrimp, Parapenaeus longirostris. Instead, COstrained Zero-Inflated GAM’s (COZIGAM) were applied to the spatio-temporal case study concerning the red shrimp, due to the high proportion of zeros in the data of Aristaeomorpha foliacea. The study shows a significance of the spa- tial variability and of the temporal evolution of the abundance of the resources considered. While depth, fishing effort, rainfall and baric indices significantly influence the deep-water rose shrimp distribution, the red shrimp distribution is only influenced by baric indices NAO and MO.File | Dimensione del file | Formato | |
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