So Long and Thanks for All the Fish: Overexploitation of the Regionally Endemic Galapagos Grouper Mycteroperca olfax (Jenyns, 1840)

Abstract

The regionally endemic Galapagos Grouper, locally known as bacalao, is one of the most highly prized finfish species within the Galapagos Marine Reserve (GMR). Concerns of overfishing, coupled with a lack of fishing regulations aimed at this species raises concerns about the current population health. We assessed changes in population health over a 30-year period using three simple indicators: (1) percentage of fish below reproductive size (Lm); (2) percentage of fish within the optimum length interval (Lopt); and (3) percentage of mega-spawners in the catch. Over the assessed period, none of the indicators reached values associated with healthy populations, with all indicators declining over time. Furthermore, the most recent landings data show that the vast majority of the bacalao caught (95.7%,) were below Lm, the number of fish within the Lopt interval was extremely low (4.7%), and there were virtually no mega-spawners (0.2%). Bacalao fully recruit to the fishery 15 cm below the size at which 50% of the population matures. The Spawning Potential Ratio is currently 5% of potential unfished fecundity, strongly suggesting severe overfishing. Our results suggest the need for bacalao-specific management regulations that should include minimum (65 cm TL) and maximum (78 cm TL) landing sizes, slot limits (64–78 cm TL), as well as a closed season during spawning from October to January. It is recognized that these regulations are harsh and will certainly have negative impacts on the livelihoods of fishers in the short term, however, continued inaction will likely result in a collapse of this economically and culturally valuable species. Alternative sources of income should be developed in parallel with the establishment of fishing regulations to limit the socio-economic disruption to the fishing community during the transition to a more sustainable management regime.

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

“…This review article employs the case study of the sailfin grouper (Mycteroperca olfax; hereinafter 'bacalao', as is locally known), an overexploited species targeted in the artisanal handline fishery of the Galapagos Islands [40], in order to illustrate the application of vulnerability assessments in marine fish in order to guide decision-making in multispecies fisheries. For such purpose, we first provided a context of the fishery, in which we examined (i) the historical perspectives and ecological impacts of the Galapagos' handline fishery, (ii) vulnerability, conservation status and drivers of overexploitation in bacalao and (iii) the progresses in monitoring and research in the fishery, and their contribution to fisheries management.…”

“…For selectivity, we accounted for the multiple hook sizes (up to 70 mm in length; [57]) used in handlines and assumed that the gear captures fish from 18 cm upwards (see [53]). Therefore, we inferred susceptibility to gear selectivity by using species' average size at maturity and maximum size, as both parameters are indicative of the effects that the gear would cause on fish populations (e.g., recruitment and/or grow overfishing; see [40]). For instance, species with a maximum size ≤ 18 (±5) cm had the lowest susceptibility to gear selectivity; whereas species with a size at maturity ≤ 18 (±5) cm were less susceptible than species with a larger one.…”

Towards locally adapted livestock production in the Galápagos islands : Characterizing & defining potential redesign strategies for the local poultry and pig production systems of Santa Cruz - Galápagos Islands, Ecuador

“…Castrejon & Charles 2013; Usseglio et al 2016) might be an argument to shift to aquaculture on the island instead of fishing, in order to alleviate the pressure on ocean and coastal ecosystems.…”

Length‐Based Assessment of an Artisanal Albulid Fishery in the South Pacific: a Data‐Limited Approach for Management and Conservation

“…; Usseglio et al. ). Additionally, to compensate for the lack of biological and catch data, other approaches suggest assessing fisheries systems from three different viewpoints: the ecology of targeted populations, their exploitation, and the broader socioeconomic fishery context.…”

“…Fortunately, novel low-cost data-limited methods are emerging that permit the assessment of data-deficient fisheries without the once essential context provided by historic abundance and long-term trends in fisheries landings (Froese 2004;Cope and Punt 2009;Prince et al 2011;Hordyk et al 2015b). These methods utilize a combination of life history parameters and the length-frequency distribution of a harvested fish population to reveal its status in a given fishery and have made substantial contributions to the management of numerous data-poor fisheries (Ault et al 2008;Nadon et al 2015;Prince et al 2015;Usseglio et al 2016). Additionally, to compensate for the lack of biological and catch data, other approaches suggest assessing fisheries systems from three different viewpoints: the ecology of targeted populations, their exploitation, and the broader socioeconomic fishery context.…”