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Schematic illustration of a hypothetical retrospective evolutionary impact assessment aiming to quantify the consequences of past fisheries-induced evolution (FIE) from the genetic trait to a global utility function. All curves, therefore, show effects of changes in the genetic component of the trait in question. The assessment compares time series of quantities of interest from an evolutionary scenario (continuous lines) with those from a non-evolutionary scenario (dashed lines) given a particular fishing regime. (a) This example focuses on FIE in a stock's average age at maturation and assumes that FIE causes fish to mature at earlier ages and smaller sizes. (b) In the evolutionary scenario, fishing results in more rapid decreases in spawning-stock biomass (SSB) and in the average body size of spawners. (c) This will influence ecosystem services: provisioning services decline because of a more strongly reduced yield, and cultural services decline, for example, because of the loss of desirable large fish. (d) This implies secondary effects on the associated socioeconomic values or utility components: direct-use values are diminished because of a less valuable total yield, and non-use values are diminished because of the loss of existence value. (e) The loss of values from provisioning and cultural services can be assessed jointly, in terms of a global utility function, which is found to decline more strongly as a result of FIE. Note that although FIE may often lead to earlier maturation at smaller sizes, as shown in this example, under particular circumstances, it may result in delayed maturation.
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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-induce...
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... types of EvoIA help address distinct challenges arising from FIE: (i) quantification of the losses or gains in utility that may result from FIE and (ii) evaluation of alternative management regimes while accounting for the potential effects of FIE. The first type, illustrated in Fig. 3, quantifies the conse- quences of FIE by including or removing the effect of FIE in a simulated fishery system. To evaluate alternative scenarios, statistical or process-based models or both are needed: an evolutionary sce- nario allowing the genetic component of traits to change in response to fishing, and a corresponding ...
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... of the target stock and other ecosystem elements and address how these demographic changes impact relevant ecosystem services and utility components (for an application to recovery dynamics, see Enberg et al. 2009). A further step could integrate utility components into a global util- ity function. In the hypothetical example illustrated in Fig. 3, this integration (i.e. the step from Fig. 3d to e) includes the direct-use value from provisioning services and the non-use value from cultural ser- vices. The example shows how a relatively small change in a genetic trait may sometimes result in a significant negative impact on global utility. How- ever, in other cases, FIE may have ...
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... elements and address how these demographic changes impact relevant ecosystem services and utility components (for an application to recovery dynamics, see Enberg et al. 2009). A further step could integrate utility components into a global util- ity function. In the hypothetical example illustrated in Fig. 3, this integration (i.e. the step from Fig. 3d to e) includes the direct-use value from provisioning services and the non-use value from cultural ser- vices. The example shows how a relatively small change in a genetic trait may sometimes result in a significant negative impact on global utility. How- ever, in other cases, FIE may have little negative impact on utility, or may even ...
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The intensive exploitation of Chilean hake (Merluccius gayi gayi gayi) in Chilean fisheries is expected to be responsible for changes in life history traits of this species, such as decreases in the mean length and in the length and age at maturity. We estimated trends related to female maturity to test whether these changes are evolutionary (genet...
Climate change is impacting the composition and functioning of virtually every ecosystem on Earth, and disrupting the productivity of exploited ones. Species are rapidly adjusting to their changing environments through evolutionary and/or plastic phenotypic changes in behavioural, physiological, phenological and life‐history traits. Size‐selective...
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-induce...
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... Intensive fisheries induce the evolution of reproductive and migration timing, as well as time and size of maturation, which may delay the recovery of commercial fisheries (Conover & Munch, 2002;Olsen et al., 2004) (SDG 1, SDG 2, SDG 3, SDG 14). Fisheries management that incorporates evolutionary thinking can substantially improve sustainable harvests and recovery from fisheries collapses (Ahrens et al., 2020;Laugen et al., 2014;Matsumura et al., 2011) (SDG 1, SDG 2, SDG 3, SDG 14). Understanding which species can and cannot evolutionarily adapt to human-induced change, including pollution and ocean acidification (Reid et al., 2016;Schlüter et al., 2014), as well as the rate of these adaptations, will be key to predicting how marine populations and communities will change in the future, impacting the effective management of many commercially important fisheries. ...
Given the multitude of challenges Earth is facing, sustainability science is of key importance to our continued existence. Evolution is the fundamental biological process underlying the origin of all biodiversity. This phylogenetic diversity fosters the resilience of ecosystems to environmental change, and provides numerous resources to society, and options for the future. Genetic diversity within species is also key to the ability of populations to evolve and adapt to environmental change. Yet, the value of evolutionary processes and the consequences of their impairment have not generally been considered in sustainability research. We argue that biological evolution is important for sustainability and that the concepts, theory, data, and methodological approaches used in evolutionary biology can, in crucial ways, contribute to achieving the UN Sustainable Development Goals (SDGs). We discuss how evolutionary principles are relevant to understanding, maintaining, and improving Nature Contributions to People (NCP) and how they contribute to the SDGs. We highlight specific applications of evolution, evolutionary theory, and evolutionary biology's diverse toolbox, grouped into four major routes through which evolution and evolutionary insights can impact sustainability. We argue that information on both within‐species evolutionary potential and among‐species phylogenetic diversity is necessary to predict population, community, and ecosystem responses to global change and to make informed decisions on sustainable production, health, and well‐being. We provide examples of how evolutionary insights and the tools developed by evolutionary biology can not only inspire and enhance progress on the trajectory to sustainability, but also highlight some obstacles that hitherto seem to have impeded an efficient uptake of evolutionary insights in sustainability research and actions to sustain SDGs. We call for enhanced collaboration between sustainability science and evolutionary biology to understand how integrating these disciplines can help achieve the sustainable future envisioned by the UN SDGs.
... Although both temperature and mortality are expected to affect mean body size in fish (Crozier & Hutchings, 2014;Marshall & McAdam, 2007;Swain et al., 2007), their importance relative to each other and to other known drivers of change such as resource availability generally remains uncertain. Given the potentially large implications of changing body size for the fisheries and ecosystems these populations support (Hočevar & Kuparinen, 2021;Laugen et al., 2014), partitioning the effects of each driver and evaluating their potential interactions is both a timely and necessary objective for conservation. ...
... The contrasts evident in mean length-at-age 4 were therefore indicative of more adverse impacts of increasing temperature in warm than cold locations, a finding with direct implications for individual fitness (Beaudry-Sylvestre et al., 2022) and more generally marine ecosystems (e.g. Hočevar & Kuparinen, 2021;Laugen et al., 2014). ...
Body size is a key component of individual fitness and an important factor in the structure and functioning of populations and ecosystems. Disentangling the effects of environmental change, harvest and intra- and inter-specific trophic effects on body size remains challenging for populations in the wild. Herring in the Northwest Atlantic provide a strong basis for evaluating hypotheses related to these drivers given that they have experienced significant warming and harvest over the past century, while also having been exposed to a wide range of other selective constraints across their range. Using data on mean length-at-age 4 for the sixteen principal populations over a period of 53 cohorts (1962–2014), we fitted a series of empirical models for temporal and between-population variation in the response to changes in sea surface temperature. We find evidence for a unified cross-population response in the form of a parabolic function according to which populations in naturally warmer environments have responded more negatively to increasing temperature compared with those in colder locations. Temporal variation in residuals from this function was highly coherent among populations, further suggesting a common response to a large-scale environmental driver. The synchrony observed in this study system, despite strong differences in harvest and ecological histories among populations and over time, clearly indicates a dominant role of environmental change on size-at-age in wild populations, in contrast to commonly reported effects of fishing. This finding has important implications for the management of fisheries as it indicates that a key trait associated with population productivity may be under considerably less short-term management control than currently assumed. Our study, overall, illustrates the need for a comparative approach within species for inferences concerning the many possible effects on body size of natural and anthropogenic drivers in the wild.
... The rate and intensity of FIE has been questioned, with work suggesting that FIE, although existent, is not an immediate issue for fish populations (compared with direct effects of fishing mortality), or is lacking genetically based evidence [7,8]. However, there have also been calls for FIE theory to be formally integrated into fisheries management as a precautionary measure [9]. Much of the research surrounding FIE has been carried out using theoretical approaches or laboratory experiments using model species [10][11][12][13], whilst quantitative evidence of selection arising from fishing and resulting in evolutionary change in wild populations remains rare or contradictory [14,15]. ...
Fishing-induced evolution (FIE) threatens the ecology, resilience, and economic value of fish populations. Traits under selection, and mechanisms of selection, can be influenced by abiotic and biotic perturbations, yet this has been overlooked. Here, we present the fishery selection continuum, where selection ranges from rigid fisheries selection to flexible fisheries selection. We provide examples on how FIE may function along this continuum, and identify selective processes that should be considered less or more flexible. We also introduce fishery reaction norms, which serve to conceptualise how selection from fishing may function in a dynamic context. Ultimately, we suggest an integrative approach to studying FIE that considers the environmental conditions in which it functions.
... Determining whether evolutionary processes are involved in the changes in the phenotypic characteristics of natural populations is important because adaptive changes may influence their longterm dynamics by modifying their productivity (Dunlop et al., 2015;Jørgensen et al., 2007;Laugen et al., 2014) and may cause changes in traits reversible only over several generations Enberg et al., 2009;Jørgensen et al., 2007;Law, 2000). ...
Declines in individuals' growth in exploited fish species are generally attributed to evolutionary consequences of size‐selective fishing or to plastic responses due to constraints set by changing environmental conditions dampening individuals' growth. However, other processes such as growth compensation and non‐directional selection can occur and their importance on the overall phenotypic response of exploited populations has largely been ignored. Using otolith growth data collected in European anchovy and sardine of the Bay of Biscay (18 cohorts from 2000 to 2018), we parameterized the breeder's equation to determine whether declines in size‐at‐age in these species were due to an adaptive response (i.e. related to directional or non‐directional selection differentials within parental cohorts) or a plastic response (i.e. related to changes in environmental). We found that growth at age‐0 in anchovy declined between parents and their offspring when biomass increased and the selective disappearance of large individuals was high in parents. Therefore, an adaptive response probably occurred in years with high fishing effort and the large increase in biomass after the collapse of this stock maintained this adaptive response subsequently. In sardine offspring, higher growth at age‐0 was associated with increasing biomass between parents and offspring, suggesting a plastic response to a bottom‐up process (i.e. a change in food quantity or quality). Parental cohorts in which selection favoured individuals with high growth compensation produced offspring high catch up growth rates, which may explain the smaller decline in growth in sardine relative to anchovy. Finally, on non‐directional selection differentials were not significantly related to the changes in growth at age‐0 and growth compensation at age‐1 in both species. Although anchovy and sardine have similar ecologies, the mechanisms underlying the declines in their growth are clearly different. The consequences of the exploitation of natural populations could be long lasting if density‐dependent processes follow adaptive changes.
... The new insights gained from our habitat-informed framework can allow the re-examination of reference points used to manage these animals. For example, a habitat-informed assessment model opens up the opportunity to create entirely new habitat-informed reference points to help take a further step towards the implementation of an ecosystem approach to fisheries (EAFM; Colloca et al., 2013 ;Laugen et al., 2014 ;Gullestad et al., 2017 ;Bastardie et al., 2021 ). One could use this approach to identify the most productive areas and set reference points based on the trends in more vital habitats, whether they be based on changes in commercial size/adult density , recruit density , absolute abundance, proportion of non-zeroes, or other habitat-specific metrics. ...
Recent efforts in ocean mapping of seafloor habitat have made data increasingly available. For bottom-dwelling and/or sessile species, there is often a strong relationship between population productivity and habitat, and stock assessment models are likely to be improved by the inclusion of habitat. Here, we extend a recently developed spatio-temporal biomass dynamics model to allow habitat to inform probabilities of non-zero tows and catchability. Simulation experiments demonstrate the ability of this new approach to reliably capture population trends over time and space, with the applicability of the method further demonstrated using data from the Canadian Maritimes Inshore Sea Scallop Fishery in the Bay of Fundy. This habitat-informed spatio-temporal biomass dynamics model better captures underlying processes, reduces uncertainty, thereby improving our understanding of stock status from which fisheries management decisions can be based.
... The impact of fishing pressure has been estimated from the natural system in various ways [23,24]. A fishery's utility represents the total benefit stakeholders derive from fishing [25,26]. The large network of inland waters will continue to offer great potential for commercial capture fisheries which consequently compete well with rapidly expand fish farming practices [27]. ...
The Yamuna River is a major river of India that originates from the Himalayan mountain system. It originates from Yamunotri in Uttarkashi district of Uttarakhand. Nile tilapia, Oreochromis niloticus, is an African freshwater cichlid and a very important food fish in the world. Nile tilapia competes with the native species in areas where it has been introduced. The Nile tilapia was intentionally introduced around the world as an aquaculture edible fish. It is a very hardy fish that can tolerate a wide range of environmental factors, making it well suited to aquaculture. It is the third most imported food fish worldwide. The non-native fish species play an important role in the landing and trade from the Yamuna River. The stock of these fish well established from the Yamuna River.
... Such a management strategy would reduce the likelihood of eliciting unpredictable or undesirable demographic changes to fish populations with these attributes. Furthermore, while the duration of our experimental study was insufficiently long to shed light on longer-term ecoevolutionary consequences of harvesting, the observed contrasting responses to size-selective harvesting among neighbouring populations reinforce that population-specific modelling may be critical in many instances (Laugen et al., 2014). The diversity of responses observed across populations in studies such as ours also has value for parameterizing population-specific models under alternate management scenarios, particularly since few experimental harvesting studies of this sort exist. ...
Sustainable harvesting of wild populations relies on evidence‐based knowledge to predict harvesting outcomes for species and the ecosystems they inhabit. Although harvesting may elicit compensatory density‐dependence, it is generally size‐selective, which induces additional pressures that are challenging to forecast. Furthermore, responses to harvest may be population‐specific and whether generalizable patterns exist remains unclear.
Taking advantage of Parks Canada's mandate to remove introduced brook trout Salvelinus fontinalis to restore alpine lakes in Canadian parks, we experimentally applied standardized size‐selective harvesting rates (the largest ~64% annually) for three consecutive summers in five populations with different initial size structures. Four unharvested populations were used as controls.
At reduced densities, harvested and control populations exhibited similar density‐dependent increases in specific growth, juvenile survival and earlier maturation. However, size‐selective harvesting simultaneously induced changes to size and age structure that contrasted among harvested populations. Average body length decreased in three of five harvested populations, whereas it tended to increase in control populations over the 3 years. We also detected contrasting, population‐specific changes in body length variability and ultimately in length‐ and age‐at‐harvest in harvested populations but not controls.
Overall, populations with smaller, more homogeneous body sizes, and living at high densities were most resilient to size‐selective harvesting, exhibiting the smallest change in size‐at‐age. In contrast, large‐bodied populations exhibited more substantial size‐structure changes following selective harvesting: large‐bodied populations experienced either stabilizing or disruptive pressures, when initial length variability was high or low, respectively.
Synthesis and application. Our results show that within species, size‐selective harvesting inherently leads to more risk and uncertainty when harvesting populations with larger and more varied body sizes than smaller‐bodied populations with less range in body size. Our study supports prioritizing regulations that protect harvested populations with larger and more varied body sizes. Such a management strategy would reduce the likelihood of eliciting unpredictable or undesirable demographic changes to fish populations with these attributes.
... Economic models of resource harvesting often ignore these complexities, although demography and trait composition are crucial for the productivity and resilience of a population, and their economic value (Zimmermann and Heino, 2013). Body size and genetic structure are directly affected by harvesting that truncates demography, triggers plastic responses and can induce evolutionary adaptation of wildlife populations (Heino et al., 2015, Conover andMunch, 2002) with detrimental effects for the sustainability and economic benefits of hunting (Allendorf and Hard, 2009) and fishing (Jørgensen et al., 2007, Laugen et al., 2014. Removing the large mature individuals leaves the small early maturing types to reproduce, favoring undesirable traits and inducing adverse selection that is antithetical to common practices in animal husbandry and breeding. ...
Fisheries typically consider short planning horizons that stand in contrast to long-term sustainability and biodiversity targets, especially when evolutionary time scales play a role. Many global fish stocks are exploited above sustainable levels, having caused fisheries-induced evolution towards smaller maturation sizes, lower growth rates, and lower economic values of individual fish. Here we couple economic decision-making with eco-evolutionary fish population dynamics to explore (1) the impact of alternative planning horizons in fisheries management on evolution and (2) the trade-off between profit and a set conservation target. We find that evolutionary decline is only reversed under century-long planning horizons. With more typical short-term planning, stock recovery in terms of biomass is achieved, but evolutionary decline continues. Setting genetic trait conservation targets only slightly reduced profits and the trade-off is further alleviated if the fishery can select for genotypes and thereby assist evolutionary reversal.
... In addition, fisheries selection may elicit evolutionary responses (e.g., Dieckmann et al., 2009;Heino et al., 2013Heino et al., , 2015Jørgensen et al., 2007;Laugen et al., 2014), which SSD may thus render sex-specific. It is therefore important to understand the evolutionary mechanisms that can lead to female-biased SSD. ...
... Since our model captures key demographic processes and can reproduce empirical data for both present and historic populations of North Sea plaice, it provides a method for assessing the evolutionary impacts caused by the North Sea plaice fishery (Heino et al., 2015;Jørgensen et al., 2007). The modeling framework introduced here could therefore become a powerful tool for exploring and evaluating alternative management measures to mitigate fisheries-induced evolution, supporting a modern Darwinian approach to fisheries management (Laugen et al., 2014). ...
Sexual size dimorphism (SSD) is caused by differences in selection pressures and life‐history trade‐offs faced by males and females. Proximate causes of SSD may involve sex‐specific mortality, energy acquisition, and energy expenditure for maintenance, reproductive tissues, and reproductive behavior. Using a quantitative, individual‐based, eco‐genetic model parameterized for North Sea plaice, we explore the importance of these mechanisms for female‐biased SSD, under which males are smaller and reach sexual maturity earlier than females (common among fish, but also arising in arthropods and mammals). We consider two mechanisms potentially serving as ultimate causes: (a) Male investments in male reproductive behavior might evolve to detract energy resources that would otherwise be available for somatic growth, and (b) diminishing returns on male reproductive investments might evolve to reduce energy acquisition. In general, both of these can bring about smaller male body sizes. We report the following findings. First, higher investments in male reproductive behavior alone cannot explain the North Sea plaice SSD. This is because such higher reproductive investments require increased energy acquisition, which would cause a delay in maturation, leading to male‐biased SSD contrary to observations. When accounting for the observed differential (lower) male mortality, maturation is postponed even further, leading to even larger males. Second, diminishing returns on male reproductive investments alone can qualitatively account for the North Sea plaice SSD, even though the quantitative match is imperfect. Third, both mechanisms can be reconciled with, and thus provide a mechanistic basis for, the previously advanced Ghiselin–Reiss hypothesis, according to which smaller males will evolve if their reproductive success is dominated by scramble competition for fertilizing females, as males would consequently invest more in reproduction than growth, potentially implying lower survival rates, and thus relaxing male–male competition. Fourth, a good quantitative fit with the North Sea plaice SSD is achieved by combining both mechanisms while accounting for sex‐specific costs males incur during their spawning season. Fifth, evolution caused by fishing is likely to have modified the North Sea plaice SSD. The paper presents a model to evolutionarily explain the sexual size dimorphism with an eco‐genetic model adapted to detailed empirical data of North Sea plaice. Behavioral investments and diminishing fitness returns are considered as alternative explanations with its implication in individual energy allocation, and put into context with the ecology of the species.
... Most fishing gears selectively capture the large and fast-growing fish in populations (positive size-selection) (Law 2007), while most natural predators target smallerthan-average sizes (negative size-selection) (Edeline and Loeuille 2021;Stige et al. 2019). Elevated mortality, even if unselective for size, is known to generally select for a fast life-history characterized by rapid maturation and fast juvenile growth, elevated reproductive investment and reduced adult growth and longevity (Hamilton et al. 2007;Heino et al. 2015;Jørgensen and Holt 2013;Laugen et al. 2014;Uusi-Heikkilä et al. 2015;Wootton et al. 2021). Positive size-selection reinforces such life-history adaptations and adds pressures to mature earlier and at smaller sizes at the expense of post-maturation growth rate (Andersen et al. 2018;Jørgensen et al. 2007). ...
Size-selective mortality is common in fish populations and can operate either in a positive size-selective fashion by harvesting larger-than-average fish or be negatively size-selective by harvesting smaller-than-average fish. Through various mechanisms (like genetic correlations among behaviour and life-history traits or direct selection on behaviour co-varying with growth rate or size-at-maturation), size-selection can result in evolutionary changes in behavioural traits. Theory suggests that both positive and negative size-selection without additional selection on behaviour favours boldness, while evolution of shyness is possible if the largest fish are harvested. Here we examined the impact of size-selective mortality on collective boldness across ontogeny using three experimental lines of zebrafish (Daniorerio) generated through positive (large-harvested), negative (small-harvested) and random (control line) size-selective mortality for five generations and then relaxed selection for 10 generations to examine evolutionarily fixed outcomes. We measured collective risk-taking during feeding (boldness) under simulated aerial predation threat, and across four contexts in presence/absence of a cichlid. Boldness decreased across ontogeny under aerial predation threat, and the small-harvested line was consistently bolder than controls. The large and small-harvested lines showed higher behavioural plasticity as larvae and developed personality earlier compared to the controls. The large-harvested line showed increased variability and plasticity in boldness throughout ontogeny. In the presence of a live predator, fish did not differ in boldness in three contexts compared to the controls, but the large-harvested line showed reduced behavioural plasticity across contexts than controls. Our results confirmed theory by demonstrating that size-selective harvesting evolutionarily alters collective boldness and its variability and plasticity.
