Influence of mesh size and tooth spacing on the proportion of damaged organisms in the catches of the Portuguese clam dredge fishery
Gaspar, M.B.; Leitão, F.M.; dos Santos, M.N.; Sobral, M.; Chícharo, L.; Chícharo, M.A.; Monteiro, C.C. (2002). Influence of mesh size and tooth spacing on the proportion of damaged organisms in the catches of the Portuguese clam dredge fishery. ICES J. Mar. Sci./J. Cons. int. Explor. Mer 59(6): 1228-1236. http://dx.doi.org/10.1006/jmsc.2002.1310
In: ICES Journal of Marine Science. Academic Press: London. ISSN 1054-3139; e-ISSN 1095-9289, more
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| Keywords |
By catch
Catching methods > Net fishing > Trawling > Bottom trawling
Damage
Dredging
Equipment > Fishery industry equipment > Fishing gear
Fisheries > Shellfish fisheries > Mollusc fisheries > Clam fisheries
Gear selectivity
Man-induced effects
Population functions > Mortality > Fishing mortality
Bivalvia [WoRMS]; Spisula solida (Linnaeus, 1758) [WoRMS]
ANE, Portugal [Marine Regions]
Marine/Coastal |
| Author keywords |
clam fishery; direct mortality; dredge; gear impact; tooth spacing; meshsize |
| Authors | | Top |
- Gaspar, M.B.
- Leitão, F.M.
- dos Santos, M.N.
- Sobral, M.
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- Chícharo, L.
- Chícharo, M.A.
- Monteiro, C.C.
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| Abstract |
Experiments to assess the effect of mesh size and tooth spacing on the catch of Spisula solida were undertaken with the aim of determining an optimal combination of these two characteristics to minimize the dredging impact on by-catch species. However, our data showed that tooth spacing, mesh size and the interactions between these two factors did not affect the number of damaged macrofaunal individual's caught. This may be because infauna entered the dredge without passing through the space between the teeth and the mesh of the net bag closed as it was stretched by the weight of the contents, preventing the escape of the caught individuals. Thus, independently of mesh size, when the dredge is towed over the sediment, the retained individuals were injured due to abrasion between animals and/or between animals and debris. The severity of injuries inflicted by dredging on different macrobenthic species is related to their morphology and fragility. |
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