The effect of an artificial reef system on the transient fish assemblages – south-eastern coast of Brazil

Abstract

Artificial reefs (ARs) are often used to improve fishing and, consequently, the economy of a region. However, the way in which the species use the reefs may vary between fish assemblages. An assessment was made of the influence of an AR complex on the transient fish population off the northern coast of Rio de Janeiro state and, therefore, two control areas were sampled. Gillnets were used to capture individual fish in six sampling surveys. Cumulative abundance and biomass curves (ABC) were used to assess the possible effects of the reefs on the community's functional structure. In the dry season, during which the influence of the Paraíba do Sul River is smaller, a larger richness of r-strategy species and juveniles of K-strategy species was observed in the reef area compared with the control areas, suggesting that the AR acts as a protective environment for these species. During the lower river discharge period the results indicated a potential disturbance in the functional structure of the AR fish community and, therefore, a less stable environment relative to the control areas. This 'instability' warrants a positive connotation, as it indicates that the artificial reefs are harbouring species that are particularly sensitive to predation, making the reef a powerful tool for maintaining these populations on the northern coast of Rio de Janeiro.

Interactions between coral restoration and fish assemblages: implications for reef management

“…Vertical topography has also been shown to have a significant effect on fish assemblages, with vertical jetty pillars experiencing much higher recruitment than low‐relief natural reefs in the Red Sea (Rilov & Benayahu, 2000). Artificial reef design and the presence of holes and cracks providing protection for prey also seem to be particularly important in defining predatory fish assemblages (Da Rocha et al ., 2015; Gregalis et al ., 2009; Spieler et al ., 2001). For example, in an experimental study where artificial reefs containing varying shelter sizes were deployed, smaller shelters were effective in excluding large predators, whereas the presence of larger holes increased the abundance of large piscivores and indirectly reduced prey numbers (Hixon & Beets, 1989).…”

Ethnoecology and socioeconomic around an artificial reef: the case of artisanal fisheries from southeastern Brazil

“…Practices that control the use of active gears should be encouraged for the Guaxindiba coast. Thus, this study and several researches along 20 years suggest that the deployment of ARs can contribute to the sustainable management of fishery resources in northern Rio de Janeiro (Zalmon et al 2002, Brotto et al 2006, Santos et al 2008, Santos et al 2010, Rocha et al 2014, Santos & Zalmon, 2015.…”

The trophic ecology of marine catfishes in south-eastern Brazil

“…As observed by Rocha et al . (2015), at times of higher PSR discharge, G. genidens and A. luniscutis were more abundant, thus contributing to higher mean THg values for both species compared with B. bagre . At times of lower PSR discharge, B. bagre is more abundant; thus as suggested by authors worldwide and for the PSR estuary, during low river discharge the main source of Hg is the direct deposition of the contaminant from the atmosphere to surface waters, resulting in higher concentrations of THg in fish due to the rapid methylation and absorption by biota, thus becoming more bioavailable (Harris et al ., 2007; Mason et al ., 2012; Araujo et al ., 2017; Azevedo et al ., 2018).…”