Anthropogenic impacts in the nearshore fish community of the Yucatan Coastal Corridor. A comparison of protected and unprotected areas

Abstract

The establishment of protected areas is one of the few management tools available to combat the deleterious effect of anthropogenic impacts, however, studies of the fish community in both protected and disturbed environments are needed as evidence of the effectiveness of those protected areas. This study aims to characterize, evaluate, and compare the environment and fish community, through 24 localities in the Yucatan Coastal Corridor, within the Reserve El Palmar (REP) and the unprotected Yucatan coastal region (UYCR). During three years, physicochemical variables and community descriptors (diversity, abundance, and evenness) were calculated for each site. The 94 fish species registered were grouped in five trophic groups (TGs), the most abundant and conspicuous are the zoobenthos, zooplankton, and nekton feeders, while omnivorous and herbivorous are scarce. To determine the anthropogenic impacts, the population size, main activities, and infrastructure of each site were considered, resulting in four categories of disturbance: (WI) without impact, inside the REP; (LI) low impact; (MI) medium impact; and (HI) high impact, within the UYCR. Multivariate analyses combining physicochemical variables, community descriptors, and TGs by impact category segregated two groups, WI-LI, with high values of salinity, fish abundance, diversity of fish and TGs, and low values of nitrites, nitrates, and ammonia, from MI-HI with the contrary characteristics. In -conclusion, 1) the protection of the REP is helping to maintain high fish diversity and abundance within and around the area, 2) the anthropogenic activities constrain the fish diversity and abundance, and 3) nitrates, nitrites, and ammonia are important variables in the determination of the ecosystem health.