Vulnerability and Decision-Making in Multispecies Fisheries: A Risk Assessment of Bacalao (Mycteroperca olfax) and Related Species in the Galapagos’ Handline Fishery

José F Pontón-Cevallos,Peter L M Goethals,Jorge R Bermúdez-Monsalve,Stijn Bruneel,José R Marín Jarrín,Jorge Ramírez-González

doi:10.3390/su12176931

Abstract

Marine fish populations can be vulnerable to overfishing, as a response of their life history, ecology, and socio-economic aspects. Vulnerability assessments, in this regard, can be used to support fisheries decision-making by aiding species prioritization. Assessments like Productivity–Susceptibility Analyses are well suited for multispecies fisheries, with low gear selectivity and insufficient fishery-independent and dependent data. Using this method, we assessed local vulnerability of the Galapagos grouper (‘bacalao’; Mycteroperca olfax) and compared it with other phylogenetically-related species caught in the Galapagos’ handline-fishery. Bacalao is an overfished regionally endemic fish species, characterized by low resilience, high market and cultural value and high spatial overlap with the fishery. Our results suggested that bacalao is a species of high management priority, requiring urgent measures to prevent fisheries’ collapse. In addition, if current fishing pressure persists, other related species may become threatened in the near future. We also evaluated different management scenarios using this approach. Results suggested that the inclusion of additional no-take zones in the marine reserve, comprising key nursery habitats (such as mangroves) and spawning aggregation sites, would be necessary to reduce species vulnerability and to benefit other related species. Improving enforcement and fishers’ compliance are essential to guarantee the effectiveness of these measures.

Highlights

IntroductionOver a third of the world ocean area has already been moderately affected from the impacts of human activities (e.g., global climate change, pollution, habitat loss and degradation, species invasions, disease, and overexploitation of resources; [1,2]), and by the effects of environmental variability (e.g., hydrographic variability, climatic cycles; [3])
We focused on bacalao’s phylogenetically-related species in this analysis, as they share similar intrinsic vulnerability [31], and it was assumed that the handline fishery was causing a similar impact on these species
Our results indicate that bacalao is a grouper that needs to be prioritized for urgent intervention in the Galapagos’ handline fishery, given its limited resilience potential, high market and cultural value, and interaction with gear and fishery spatial dynamics

Summary

Introduction

Over a third of the world ocean area has already been moderately affected from the impacts of human activities (e.g., global climate change, pollution, habitat loss and degradation, species invasions, disease, and overexploitation of resources; [1,2]), and by the effects of environmental variability (e.g., hydrographic variability, climatic cycles; [3]). Fishing affects fish populations through direct mortality on target species, and through indirect effects such as by-catch, habitat destruction, functional alterations of ecosystems, and human-induced evolutionary shifts in populations [7,8]. Notwithstanding, fishing (especially small-scale) plays a vital role in health nutrition, food security, and economic development of humans, especially coastal societies [9,10]. Fish meat provides nearly 20% of animal protein intake to up to one-third of the human population; with small-scale fisheries contributing two-thirds of this amount [9,11]

Methods

Results

Conclusion