Predicting changes to macrobenthic communities due to fishing disturbance in a shrimp fishing ground of the Mexican central Pacific

• Main Authors: Godínez Domínguez, Enrique, Freire Botana, Juan Manuel, González Sansón, Gaspar
• Format: Publication
• Language: English
• Published: 2002
• Subjects: Biomass spectra; Diversity; Dominance; Fishing disturbance; Macroinvertebrate community structure; Shrimp fisheries; Spatial segregation; Species-area curve; Trawl; Tropical shelf ecosystems

We test predicted short-term structural changes in the macroinvertebrateassemblages of a shrimp fishing ground in the tropical Mexican Pacific subject tolow effort with seasonal closures. During two years, five cruises were carried outsampling seven sites and four depths (20, 40, 60 and 80 m) along 100 km ofcoastline. A series of community structure descriptors were used to determine theecological effects of fishing disturbances: ABC curves, W-statistic, normalizedspecies size distribution as biomass spectra, spatial segregation index, Shannon-Wiener diversity index, species richness and biomass. Theoretical predictions of theeffects of fishing on these indices were tested by comparisons of samples collectedfrom successive open and close fishing seasons. ABC curves show fishing hasproduced a state of chronic disturbance in the macroinvertebrate community. Shorttermeffects could be masked by natural seasonal and interannual environmentalchanges. Results of the analyses of short-term effects are not in agreement with thefishing disturbance theories; only in 31% of the cases the results obtained ofcomparisons between successive cruises to test the different hypotheses about theeffects of fishing were in agreement with theory. The temporal trend of increase ofthe biomass and the decline of species richness, could evidence interannual effects.The complexity of the sources of variability in a exploited community forces to focuson temporal and spatial gradients to understand the community structuralprocesses