Space-time variations of megazoobenthos subject to natural and anthropogenic impacts in two Cuban bays: evidence of recovery?

Abstract

The spatiotemporal variations of megazoobenthos on soft bottoms in Buena Vista (BV) and San Juan de Los Remedios (SJR) bays, Cuba, were assessed to infer the effects of the elimination of bottom trawl fisheries and the creation of protected areas. Data were collected at 11 sites in 2010-2013 (six routines and five exploratories) and 11 sites in 2014-2017 (four routines and seven exploratories). Samples were obtained by dredging. Mollusks were the most frequent and diverse group, followed by echinoderms and crustaceans. Total density (7.60 ind m-2) and biomass (15.82 g m-2) of the benthic community were highest in SJR in 2015. Although total biomass was lower at BV (t = 2.21; P = 0.032), there were no significant differences in density between bays (t = 0.77; P = 0.444). The site with a lower total density and biomass was located at BV. There were no differences between years except at one site, where density increased between 2010 and 2017. Total density and biomass were not significantly different inside and outside of the Zone Under Special Regime of Use and Protection (ZUSRUP) at the beginning of the sampled period. However, both density and biomass were significantly higher within the ZUSRUP at the end (2017), which suggests this protected area’s effectivity. The progressive increase in density at one site and greater density and biomass values at SJR, where bottom trawl fisheries were more intensive, suggest eliminating bottom trawl nets may have contributed to the benthic fauna recovery.