Evaluating the Potential Effectiveness of Compensatory Mitigation Strategies for Marine Bycatch

Abstract

Conservationists are continually seeking new strategies to reverse population declines and safeguard against species extinctions. Here we evaluate the potential efficacy of a recently proposed approach to offset a major anthropogenic threat to many marine vertebrates: incidental bycatch in commercial fisheries operations. This new approach, compensatory mitigation for marine bycatch (CMMB), is conceived as a way to replace or reduce mandated restrictions on fishing activities with compensatory activities (e.g., removal of introduced predators from islands) funded by levies placed on fishers. While efforts are underway to bring CMMB into policy discussions, to date there has not been a detailed evaluation of CMMB's potential as a conservation tool, and in particular, a list of necessary and sufficient criteria that CMMB must meet to be an effective conservation strategy. Here we present a list of criteria to assess CMMB that are tied to critical ecological aspects of the species targeted for conservation, the range of possible mitigation activities, and the multi-species impact of fisheries bycatch. We conclude that, overall, CMMB has little potential for benefit and a substantial potential for harm if implemented to solve most fisheries bycatch problems. In particular, CMMB is likely to be effective only when applied to short-lived and highly-fecund species (not the characteristics of most bycatch-impacted species) and to fisheries that take few non-target species, and especially few non-seabird species (not the characteristics of most fisheries). Thus, CMMB appears to have limited application and should only be implemented after rigorous appraisal on a case-specific basis; otherwise it has the potential to accelerate declines of marine species currently threatened by fisheries bycatch.

Decline of Sooty Shearwaters, Puffin us griseus, on The Snares, New Zealand

“…Additionally, the introduction ofWeka, Gallirallus australis (Sparrman, 1786), an endemic rail, to several TltI Islands in the early twentieth century may have added to ongoing harvest pressure on chicks (see Kitson & Moller 2008). However, the factors regulating shearwater populations and potential compensation for these added predation and harvest impacts are unknown (Moller 2006) and, in general, the impacts of added chick losses are likely to be much lower than predation of adults (Hamilton & Moller 1995, Hunter & Caswell 2005, Wilcox & Donlan 2007, Finkelstein et al 2008. If a high level of inter-island movement is typical for Sooty Shearwater populations, as seen for Short-tailed Shearwater (SIdra 1991), The Snares population may be affected by population declines occurring elsewhere, potentially driven by predation by rats and Weka and harvesting of chicks.…”

Fisheries bycatch reduction within the least-cost biodiversity mitigation hierarchy: Conservatory offsets with an application to sea turtles

“…5 Conservatory offsets correspond to the `Polluter Pays Principle' in that the party inflicting bycatch is responsible for paying or otherwise compensating for it (strict rather than negligence liability). 6 The inflicting party has a Willingness to Pay to the affected party (other right holders, the State, etc.) that holds the right to no or reduced bycatch and the Willingness to Accept compensation.…”

“…Their costs, and hence prices, will correspondingly differ, since they form under different circumstances and objectives. 6 A tax could incentivize changes in producer and consumer behavior and the proceeds finance costs of conservatory offsets [5,7,8,11,17,19,20,23]. The tax is ideally levied on bycatch mortality (i.e.…”

“…Several quarters delivered critiques of both compensatory and compensatory offsets for bycatch [4,6,24]:…”

Why study bycatch? An introduction to the Theme Section on fisheries bycatch

“…With sufficient data on population metrics and the distribution of bycatch events, researchers can explore the economic and conservation tradeoffs associated with alternative management approaches (Wilcox & Donlan 2007). Furthermore, if no viable alternatives exist, research provides a justification for making difficult management decisions (Finkelstein et al 2008). Without the insights provided by further bycatch research, efforts to prioritize areas, times, fisheries, and/or species for conservation purposes may be inefficient or even counterproductive.…”