Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management

Abstract

Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries-induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life-history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. EvoIA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries.

Evolutionary impact assessment of the North Sea plaice fishery

“…To assess management scenarios that help mitigate FIE, the incurred short-term losses in yield need to be weighed against the accrued long-term gains (Laugen et al 2014). For each year y a management scenario is evaluated, we therefore compare the yield Y evol,y resulting in the evolutionary model with the yield Y static,y resulting in a corresponding nonevolutionary model, in which genetic trait values are kept static at present values and population changes occur only because of demographic processes.…”

“…On the decadal time scale on which the benefits of evolutionarily informed management accrue, even low discount rates have a major influence on the economic assessment. From a conservation point of view, however, one may argue that the possibilities for future generations to harvest a fish stock should not be discounted against present yield (Laugen et al 2014). While the millennial time frame we have used to study evolutionary equilibration is not proposed to be relevant for contemporary fisheries management, the multidecadal time frame over which FIE affects yield is comparable to that of other processes affecting stock productivity, such as climate change (Blanchard et al 2012).…”

“…To estimate the consequences of ignoring FIE in fisheries management, the results are compared with those of a model with static life-history traits. As such, our study is an example of an evolutionary impact assessment (EvoIA) as first suggested by Jørgensen et al (2007) and elaborated upon by Laugen et al (2014).…”

The Effectiveness of Co-management Practices: The Case of Small-scale Fisheries in Sri Lanka

“…Size limits has been used as a classical management strategy to control overfishing [20]. However, recent studies argue that large individuals contribute to reproduction so that selectivity for large individuals may negatively affect fish population [21]. Multi species pre-dominated small-scale fisheries in developing countries where size limits are complicated [22].…”

Tallas de captura de Prochilodus mariae en la parte alta del río Meta, Orinoquia colombiana

“…Sin embargo no se ha realizado un análisis del comportamiento de las tallas de captura y de madurez sexual de esta especie en los ríos donde se lleva a cabo su pesquería en Colombia, aspecto importante de evaluar ya que la pesquería remueve de la población los individuos adultos de mayor talla y favorece individuos que ponen su energía para reproducirse temprano a menor tamaño (Stearns, 1992 citado en Uusi-Heikkil et al, 2015), lo cual puede afectar la población al reducir la fecundidad y el reclutamiento y aumentar la sensibilidad a cambios ambientales (Laugen et al, 2014) .…”