MEPS 169:303-305 (1998)  -  doi:10.3354/meps169303

Influence of tow duration and tooth length on the number of damaged razor clams Ensis siliqua

Miguel B. Gaspar1,*, Margarida Castro2, Carlos C. Monteiro1

1Instituto de Investigação das Pescas e do Mar, Centro Regional de Investigação Pesqueira do Sul, Avenida 5 de Outubro s/n, P-8700 Olhão, Portugal
2Universidade do Algarve, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Campus de Gambelas, P-8000 Faro, Portugal
*E-mail:

ABSTRACT: The incidence of shell damage due to dredging was studied in the bivalve Ensis siliqua off Lagos, on the south coast of Portugal. Three tow durations (1, 3 and 5 min) and 2 tooth lengths (30 and 40 cm) were investigated. Both factors affected the proportion of damaged individuals. The increase of tooth length results in lower proportions of damaged razor clams. An increase in tow duration increased total numbers caught but also increased the proportion of damaged clams. It is suggested that dredges with 40 cm teeth and tows of 1 min duration should be used in this fishery, although experiments should be undertaken in order to evaluate the environmental and ecological impact of dredges.


KEY WORDS: Dredge · Ensis siliqua · Indirect mortality · Bivalve


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