Low connectivity compromises the conservation of reef fishes by marine protected areas in the tropical South Atlantic

Clarissa Akemi Kajiya Endo,Luciano Ponzi Pezzi,Leonardo Nascimento Lima,Douglas Francisco Marcolino Gherardi

doi:10.1038/s41598-019-45042-0

Clarissa Akemi Kajiya Endo, Luciano Ponzi Pezzi + Show 2 more

Open Access

https://doi.org/10.1038/s41598-019-45042-0

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Abstract

The total spatial coverage of Marine Protected Areas (MPAs) within the Brazilian Economic Exclusive Zone (EEZ) has recently achieved the quantitative requirement of the Aichii Biodiversity Target 11. However, the distribution of MPAs in the Brazilian EEZ is still unbalanced regarding the proportion of protected ecosystems, protection goals and management types. Moreover, the demographic connectivity between these MPAs and their effectiveness regarding the maintenance of biodiversity are still not comprehensively understood. An individual-based modeling scheme coupled with a regional hydrodynamic model of the ocean is used to determine the demographic connectivity of reef fishes based on the widespread genus Sparisoma found in the oceanic islands and on the Brazilian continental shelf between 10° N and 23° S. Model results indicate that MPAs are highly isolated due to extremely low demographic connectivity. Consequently, low connectivity and the long distances separating MPAs contribute to their isolation. Therefore, the current MPA design falls short of its goal of maintaining the demographic connectivity of Sparisoma populations living within these areas. In an extreme scenario in which the MPAs rely solely on protected populations for recruits, it is unlikely that they will be able to effectively contribute to the resilience of these populations or other reef fish species sharing the same dispersal abilities. Results also show that recruitment occurs elsewhere along the continental shelf indicating that the protection of areas larger than the current MPAs would enhance the network, maintain connectivity and contribute to the conservation of reef fishes.

Highlights

Reef fish fauna of the South Atlantic oceanic islands and coastal shelf are known to have a high rate of endemism (c.25%1) that has contributed to shape the biogeographical patterns observed today
Simulations show that, overall, total distances are less variable in summer than in winter (Fig. 1), with some larvae moving to the north and others moving to the south, influenced by the bifurcation of the southern branch of the South Equatorial Current
Mortality by lethal high temperature was more frequent in the marine protected areas (MPAs) of Recife dos Corais (RC) and Manuel Luis (ML); during the summer and during the winter it was concentrated at RC and Costa dos Corais (CC)

Summary

Introduction

Reef fish fauna of the South Atlantic oceanic islands and coastal shelf are known to have a high rate of endemism (c.25%1) that has contributed to shape the biogeographical patterns observed today. Www.nature.com/scientificreports scales, such as the water temperature, the three-dimensional velocity field and the seasonal and interannual ocean variability that interacts with the biological traits to determine the connection pathways of eggs and larvae from different populations.

Results

Conclusion