Acronym NA
Category
Fisheries
Title Study of basket trap selectivity for changeable nassa (Nassarius mutabilis) Programme Nat. Programme (supported by ESIF)
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National-European Coordinator Gianna Fabi Coordinator email gianna.fabi@cnr.it
Coordinator institution
CNR - National Research Council (Italy)
Institutions involved
NA - Associazione produttori piccola pesca Ancona (Italy) ,
Start year 2002 End year 2004 Funding (€) € 59,404 Website NA Summary Size selectivity of basket traps for changeable nassa (Nassarius mutabilis) was estimated through comparative trials with traps varying in mesh size and net colour. Selectivity curves of two commercial white twine and 19mm black twine) and three experimental (23, 26 and 28mm white twine) traps were estimated using SELECT method. In addition, theoretical size-selectivity curves were calculated from morphometric data using a simplified version of Sechin method. Differing from the opinion of fishermen, N. mutabilis did not show any preference for dark colouredtwine. Retention curves estimated with SELECT method had a very sharp selectivity and well fitted catch data in all cases. Theoretical size-selectivity curves were very close to size-selectivity curves obtained from experimental data. The two types of curve were very similar in shape, although the theoretical ones were shifted towards larger size classes and showed a slightly steeper slope than SELECT curves. The mesh size commonly used by fishermen is not adequate for rationally exploiting the resource, as catches mainly included undersized specimens, whilst the 23 and 26mm mesh sizes would represent a good compromise between reduced occurrence of undersized individuals and satisfactory yields of commercial product.
The project aimed at studying the size selectivity of basket traps for changeable nassa (Nassarius mutabilis) commonly used to catch Nassarius mutabilis from fall to spring. The objective of the project was to provide management information to reduce the catch of undersized specimens of Nassarius mutabilis having a total length < minimum legal size (20 mm) and to contribute to preserve the ichthyic resource.
Keywords
Fishing technology;
Mollusc;
Gear technology;
Traps;
Gear selectivity;
Changeable nassa;
Shellfish;
Small scale fisheries;
Gastropod;
Marine Region
74
Northern Adriatic (GSA 17)
1
Marine Region Map
