Effects of mesh size and towing speed on the multispecies catch rates of historical swept area surveys

• Published in: Fisheries research 2015-04, Vol.164, p.143-152
• Main Authors: Manjarrés-Martínez, Luis M., Gutiérrez-Estrada, Juan C., Hernando, José A.
• Format: Article
• Language: English
• Subjects: Bottom trawl; Catch per unit effort; Demersal; Generalized linear models; Standardization
• ISSN: 0165-7836; 1872-6763
• DOI: 10.1016/j.fishres.2014.11.006

The use of different trawl nets is a factor to be considered when analysing historical swept-area research surveys aimed to characterize temporal variations in the relative abundance of demersal resources. If factors that may affect the performance of the bottom trawls were considered, more reliable temporal trends could be established. Due to the high species diversity that characterizes tropical areas, this kind of analysis is often carried out at the multispecies level. Therefore, the objective of this study was to establish the effect of two technical factors, mesh size and towing speed on the multispecies catch rates obtained in different demersal surveys carried out in the Colombian Caribbean Sea between 1988 and 2001, using two generalized linear models: one covering the entire study area and another restricted to one eco-region. For the global model, the effect of the mesh size on the multispecies catch rates was marginally significant (p0.10). In contrast, for the eco-region model, the effect of mesh size was not significant (p>0.10), while towing speed had a significant effect (p