Evaluating the conservation and economic performance of fisheries quota baskets in Belize

About

Quota baskets, which manage groups of species with similar traits using a single catch or effort limit, represent a promising approach for managing data-limited multi-species fisheries. Single-species assessment and management approaches are data-intensive and are simply not applicable in most fisheries contexts. Furthermore, even in data-rich contexts, rigid single-species approaches sacrifice the economic and nutritional benefits of multi-species fisheries when they require the conservation of “weak” stocks, i.e., stocks with lower productivity and/or higher vulnerability than the primary target stocks. Well-designed quota baskets may be able to balance conservation and socioeconomic objectives for data-limited species. However, a key challenge to implementing effective quota baskets is the lack of tools for validating the expected performance of proposed quota baskets and the lack of guidance for deriving catch or effort limits that achieve fisheries objectives, especially when data is limited.
 
In this project, we developed a flexible method of evaluating the effectiveness of proposed quota baskets and leveraged this approach to provide guidance on how to set effective catch limits. We evaluated quota baskets proposed for the management of marine fisheries in Belize as a case study. 

Approach

We leveraged a bioeconomic model developed by Collado et al. (2021) that incorporates the ability of fishers to switch gears and target different fisheries when confronted with quota basket management. Importantly, the model is parameterized using data from publicly available global-scale datasets and meta-analyses, which allows for it to be implemented in nearly any setting. We measured the performance of the proposed quota baskets in terms of their ability to keep the biomass of all species above a BMSY management target (conservation performance) and their ability to maximize multi-species profits (economic performance). In this framework, a high-performing quota basket would achieve a high proportion of the cumulative single-species harvest without compromising the conservation status of any one species in the basket. We evaluated the performance of 10 of 13 quota baskets proposed to manage 48 marine fish species in Belize. 

Key findings

Of the ten evaluated baskets, two were deemed highly functional, in that they could be fished above 65% of the cumulative single-species MSY of constituent species and still maintain all constituent species above the BMSY management target: (a) Basket 5 - forereef/handline and (b) Basket 8 - pelagic/migratory handline. Two baskets were deemed non-functional, in that they must be fished below 30% of the cumulative single-species MSY to keep all species above the BMSY management target: (a) Basket 1 - pelagic/migratory and (b) Basket 9 - large groupers. The remaining six baskets were deemed moderately functional, in that they can only be fished between 30%-65% of the cumulative single-species MSY to maintain all species above the BMSY management target. 

In general, quota baskets perform best – i.e., they are able to maximize profits while achieving conservation goals – when the stocks managed in the baskets exhibit similar vulnerabilities. Stocks with more similar vulnerabilities, which is measured by their productivity and catchability, can endure more similar harvest rates, which means that harvest rates do not have to be as conservatively reduced to protect the weaker of the stocks.

This study provides a transferable and flexible tool for evaluating the performance of quota baskets in other fisheries worldwide. Automating this process could empower a wider community of users to evaluate the performance of quota baskets in their fishery systems.

Partners

This project was a collaboration with the Environmental Defense Fund.