Exceptionally high but still growing predatory reef fish biomass after 23 years of protection in a Marine Protected Area

Abstract

Marine Protected Areas (MPAs) help replenish fish assemblages, though different trophic levels may show diverse recovery patterns. Long-term protection is required to achieve total recovery but poaching events may prevent the achievement of full carrying capacity. Here, we have analysed the effect of long-term protection on the entire reef fish community and the different trophic levels in the Cabo de Palos-Islas Hormigas MPA (SE Spain; SW Mediterranean Sea) in order to assess their recovery patterns after 23 years of protection. We compared the values for carrying capacity obtained with the maximum values achieved at regional scale, and we assessed the effect of a reduction in the surveillance over a few years, during which poaching events increased, on the recovery patterns. We found that, overall, biomass of fishes increased with time while density diminished. In particular, piscivorous and macro-invertivore fish increased while the other trophic groups remained constant or declined, suggesting top-down processes. For the entire study period, those trophic groups were approaching carrying capacity; however, when accounting only for the period in which enforcement was high and constant, they grew exponentially, indicating that full carrying capacity may have not been achieved yet. When compared to other Mediterranean MPAs, the Cabo de Palos-Islas Hormigas MPA showed values for biomass that were disproportionately higher, suggesting that local factors, such as habitat structure and associated oceanographic processes, may be responsible for the dynamics found. Our results help to understand the potential trajectories of fish assemblages over a consolidated MPA and highlight empirically how the reduction of surveillance in a period may change the recovery patterns.

Multiple indices on different habitats and descriptors provide consistent assessments of environmental quality in a marine protected area

“…Indices of exploited fish and food webs (Exploited fish and HLP) showed similar trends as they focus mostly on the same species: approximately 75% of high-level predators are actually commercially exploited. The average biomasses of exploited fish and HLP we estimated in Capo Carbonara MPA are comparable to those found in other regional-scale studies where the MPA management was deemed sufficient to obtain measurable effects on fish (Di Franco et al, 2009;Guidetti et al, 2014;Guidetti et al, 2019;Rojo et al, 2021).…”

Atual Cenário da Proteção Patentária de Tecnologias de Beneficiamento de Pescado do Brasil

“…Existe uma importante preocupação em relação às práticas predatórias da pesca que vêm continuamente reduzindo os estoques naturais, gerando um grande número de desafios para a indústria do pescado (POLACHECK, 2006;ROJO;ANADÓN;GARCÍA-CHARTON, 2021). De um lado, muito se discute em relação à gestão sustentável dos recursos pesqueiros e a migração para a produção aquícola.…”

Quotas regulation is necessary but not sufficient to mitigate the impact of SCUBA diving in a highly visited marine protected area

“…The Cabo de Palos -Islas Hormigas marine reserve (hereafter CPMR) is considered one of the most ecologically effective MPAs in the whole of the Mediterranean Sea (García-Charton et al, 2004;Rojo et al, 2021a;Rojo et al, 2021b), hosting a disproportionally high biomass of the rocky reef fish assemblage compared to other effective Mediterranean MPAs, encompassing high densities of large-size predators around the rocky shoals and small islets characterising the reserve (Rojo et al, 2021a;Rojo et al, 2021b). For this reason, the area is considered one of the most attractive Mediterranean diving destinations, and as a result the number of diving charter businesses operating in the area increased from 1 to 9 since the establishment of the MPA, and the number of divers visiting the MPA each year increased from about 8,000 in 1998 to more than 32,000 in 2017.…”