Improving the productivity-susceptibility analysis to assess data-limited fisheries

Abstract

Each year, millions of marine aquarium fish and invertebrates are harvested from coral reefs and enter the complex and largely unregulated marine aquarium trade (MAT). It is challenging to identify species at risk of overexploitation in this trade due to its data-limited and poorly monitored nature. We developed a new analytical approach based on a productivity-susceptibility analysis (PSA) to assess the vulnerability of wild-captured marine aquarium fish. The PSA was originally developed to assess food fisheries; however, species and operational characteristics between food fisheries and the MAT differ. Thus, we improved a prior PSA framework to assess the data-limited MAT through customization of productivity and susceptibility factors to align with the target fishery, improved data binning, calculation of susceptibility, and characterization of the vulnerability scores. Our vulnerability results align well with the most recent IUCN assessments, showing improved accuracy using this revised PSA compared to prior adaptions of the PSA to the MAT. Further, we show that this PSA approach can be used to assess species on either a global or country-specific scale. A Gaussian mixture model clustering algorithm was applied to the PSA results to objectively classify fish along a sustainability continuum. Among 32 species, a majority of species clustered as highly sustainable or sustainable indicating little management or over-harvest concern; however, the Bangaii cardinalfish Pterapogon kauderni and blue tang Paracanthurus hepatus indexed as unsustainable. This novel PSA method, and use of a clustering algorithm to classify results, provides a predictive tool for a wide range of fisheries. In addition to informing species management plans, the compilation of sustainability status data generated by our PSA can inform a consumer guide, allowing consumers and other stakeholders to make sustainable decisions when purchasing fish.

Can the global marine aquarium trade (MAT) be a model for sustainable coral reef fisheries?

“…That most are invertebrates reaffirms the need to include all MAT-targeted species, while the presence of lower trophic species reflects high demand for cheap “clean-up crew,” i.e., those that perform ecological functions ( 8 ). Of the six fish species, only the Banggai cardinalfish ( P. kauderni ) has been assessed previously at the global level ( 16 , 23 ). This species’ high risk ratio reaffirms it as a clear priority for MAT management ( 16 ), aligning with its endangered IUCN red list status (table S3).…”

“…Of the six fish species, only the Banggai cardinalfish ( P. kauderni ) has been assessed previously at the global level ( 16 , 23 ). This species’ high risk ratio reaffirms it as a clear priority for MAT management ( 16 ), aligning with its endangered IUCN red list status (table S3). Distribution surveys ( 24 ), the next step in data-limited management frameworks ( 25 ), confirmed only a 34-km 2 area of occupancy, which if incorporated here would generate an even higher risk ratio, reinforcing the need for management already implemented/planned.…”

“…Although relative vulnerability for a minority of MAT fish species has been estimated using productivity susceptibility analysis ( 16 ), a species’ vulnerability score does not reliably predict overexploitation risk ( 17 ). To obviate these issues and to include data-absent fish and all invertebrates, we used extent of species occurrence as a population size proxy.…”

Evolution, Development and Ecology of Anemonefishes

“…clarkii as highly vulnerable in their analysis of Indonesian ornamental reef fish susceptibility. However, a more recent analysis by Baillargeon et al (2020) classified A. biaculeatus, A. ocellaris, and A. percula as "sustainable" and A. clarkii as "highly sustainable" using their new algorithm. The major difference between this study and the others was based not on the productivity scores, but on how susceptibility is estimated and geographic location.…”

Evaluating Species at Risk in Data-Limited Fisheries: A Comprehensive Productivity-Susceptibility Analysis of the Most Traded Marine Aquarium Fish

“…Commercial aquaculture is concentrated in western countries who have historically played the role of major importing nations in the trade, instead of supplementing fishing livelihoods with cultured production in native ranges (Tlusty, 2002). Species harvested for the MAT are particularly data-deficient as they are: (1) less voluminous in trade compared to food fish, (2) often harvested from remote, biodiversity hotspots throughout the coral triangle, (3) and remote locations limits catch reporting in a traditional framework that results in long term datasets (Wood 2001a;Wood 2001b;Fujita et al 2014;Dee et al 2014;Okemwa et al 2016;Dee et al 2019;Baillargeon et al 2020;Biondo and Burki 2020). A successful method to rapidly assess the vulnerability of a species to fishing activity within a datalimited context is the productivity-susceptibility analysis (Hobday et al 2007, Patrick et al 2009.…”