Thomas Klefoth

Bio: Thomas Klefoth is an academic researcher from Leibniz Association. The author has contributed to research in topics: Fishing & Pike. The author has an hindex of 23, co-authored 41 publications receiving 1797 citations. Previous affiliations of Thomas Klefoth include Bremen University of Applied Sciences & Humboldt University of Berlin.

A behavioral perspective on fishing-induced evolution

Abstract: The potential for excessive and/or selective fishing to act as an evolutionary force has been emphasized recently. However, most studies have focused on evolution of life-history traits in response to size-selective harvesting. Here we draw attention to fishing-induced evolution of behavioral and underlying physiological traits. We contend that fishing-induced selection directly acting on behavioral rather than on life-history traits per se can be expected in all fisheries that operate with passive gears such as trapping, angling and gill-netting. Recent artificial selection experiments in the nest-guarding largemouth bass Micropterus salmoides suggest that fishing-induced evolution of behavioral traits that reduce exposure to fishing gear might be maladaptive, potentially reducing natural recruitment. To improve understanding and management of fisheries-induced evolution, we encourage greater application of methods from behavioral ecology, physiological ecology and behavioral genetics.

Recreational fishing selectively captures individuals with the highest fitness potential

Abstract: Fisheries-induced evolution and its impact on the productivity of exploited fish stocks remains a highly contested research topic in applied fish evolution and fisheries science. Although many quantitative models assume that larger, more fecund fish are preferentially removed by fishing, there is no empirical evidence describing the relationship between vulnerability to capture and individual reproductive fitness in the wild. Using males from two lines of largemouth bass (Micropterus salmoides) selectively bred over three generations for either high (HV) or low (LV) vulnerability to angling as a model system, we show that the trait “vulnerability to angling” positively correlates with aggression, intensity of parental care, and reproductive fitness. The difference in reproductive fitness between HV and LV fish was particularly evident among larger males, which are also the preferred mating partners of females. Our study constitutes experimental evidence that recreational angling selectively captures individuals with the highest potential for reproductive fitness. Our study further suggests that selective removal of the fittest individuals likely occurs in many fisheries that target species engaged in parental care. As a result, depending on the ecological context, angling-induced selection may have negative consequences for recruitment within wild populations of largemouth bass and possibly other exploited species in which behavioral patterns that determine fitness, such as aggression or parental care, also affect their vulnerability to fishing gear.

Opinion: Governing the recreational dimension of global fisheries.

Abstract: Fisheries provide food. In industrialized nations, the overwhelming portion of seafood comes from a small number of commercial fishers and increasingly aquaculture (1). Fisheries also contribute to leisure and recreation. In developed nations, 1 in 10 people fishes for pleasure, amounting to at least 220 million recreational fishers worldwide (2, 3)—more than 5 times the number of commercial capture fishers (1). This means that the vast majority of people fishing today do so recreationally (Fig. 1). For too long, the considerable importance and impacts of recreational fisheries have been ignored. Image credit: Florian Mollers (photographer). And yet, for too long, the considerable importance and impacts of recreational fisheries have been ignored. Policymakers and managers need to acknowledge and address the recreational fisheries sector, rethink management objectives and schemes, involve recreational fishers in decision-making processes, incentivize sustainable angler behavior, and improve data collection and monitoring. Recreational fisheries deserve to be considered on equal footing with commercial fisheries, particularly in mixed coastal fisheries. Although commercial capture fisheries globally harvest about 8 times the fish biomass caught by recreational fisheries (4), in many localities recreational landings now rival or even exceed the biomass removals by commercial fisheries. In inland waters in the temperate zone, recreational anglers are now the predominant users of wild fish stocks (5), and recreational fishers have become prevalent in many coastal and marine fisheries (6, 7). Globally, recreational fishers catch about 47 billion individual fish per year, of which more than half are released alive (4), either because of harvest regulations or in response to personal ethics (8). Despite high release rates, fishing for food is a strong motive and justification for recreational fisheries (9). Beyond nutritional benefits, recreational fisheries provide a range of psychological, social, educational, and economic benefits to fishers and society that are … [↵][1]2To whom correspondence should be addressed. Email: arlinghaus{at}igb-berlin.de. [1]: #xref-corresp-1-1

Passive gear‐induced timidity syndrome in wild fish populations and its potential ecological and managerial implications

Abstract: Human exploitation of wild-living animals has been suggested to create a ‘landscape of fear’. A consequence could be that individuals surviving intensive harvesting, either as a result of behavioural plasticity and/or evolutionary change, exhibit increased average timidity. In the aquatic world, such effects are particularly well documented in passively operated fishing gears common to many commercial and recreational fisheries, such as angling, trapping or gill netting. We thus propose that an exploitation-induced timidity syndrome should be a widespread pattern in fisheries. Importantly, we argue that the syndrome can be associated with several ecological and managerial consequences for social groups, populations, food webs, fisheries and assessment of stocks. We suggest research priorities to deepen our understanding of how exploited fish populations behaviourally respond to harvesting.

Understanding and Managing Freshwater Recreational Fisheries as Complex Adaptive Social-Ecological Systems

Abstract: The state of knowledge on the science and management of freshwater recreational fisheries is reviewed, with the objective of integrating insights from disparate fields such as fisheries science, environmental complexity theory, common-pool-resource theory, and resilience theory. First, freshwater recreational fisheries are characterized as complex adaptive social-ecological systems (SESs). Subsequently, two interrelated frameworks, drawing on the Ostrom framework for the analysis of SESs and adaptive management as key foundations, are presented. These frameworks are useful to structure the complexity and apprehend the various feedbacks and links inherent in any particular recreational fisheries system. Moreover, the frameworks help to identify operational management strategies in the face of substantial social-ecological uncertainty. It is concluded that to understand and manage freshwater recreational fisheries as complex adaptive SESs, a sustained shift from disciplinary to inter- and sometimes ...

Computation And Interpretation Of Biological Statistics Of Fish Populations

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Animal personalities: consequences for ecology and evolution

Abstract: Personality differences are a widespread phenomenon throughout the animal kingdom. Past research has focused on the characterization of such differences and a quest for their proximate and ultimate causation. However, the consequences of these differences for ecology and evolution received much less attention. Here, we strive to fill this gap by providing a comprehensive inventory of the potential implications of personality differences, ranging from population growth and persistence to species interactions and community dynamics, and covering issues such as social evolution, the speed of evolution, evolvability, and speciation. The emerging picture strongly suggests that personality differences matter for ecological and evolutionary processes (and their interaction) and, thus, should be considered a key dimension of ecologically and evolutionarily relevant intraspecific variation.

The ecological causes of individual specialisation

Abstract: Many generalist populations are composed of specialised individuals, whose niches are small subsets of the population niche. This 'individual specialisation' is a widespread phenomenon in natural populations, but until recently few studies quantified the magnitude of individual specialisation and how this magnitude varies among populations or contexts. Such quantitative approaches are necessary for us to understand how ecological interactions influence the amount of among-individual variation, and how the amount of variation might affect ecological dynamics. Herein, we review recent studies of individual specialisation, emphasising the novel insights arising from quantitative measures of diet variation. Experimental and comparative studies have confirmed long-standing theoretical expectations that the magnitude of among-individual diet variation depends on the level of intra and interspecific competition, ecological opportunity and predation. In contrast, there is little empirical information as to how individual specialisation affects community dynamics. We discuss some emerging methodological issues as guidelines for researchers studying individual specialisation, and make specific recommendations regarding avenues for future research.

Recent models for adaptive personality differences: a review

Abstract: In this paper we review recent models that provide adaptive explanations for animal personalities: individual differences in behaviour (or suites of correlated behaviours) that are consistent over time or contexts. We start by briefly discussing patterns of variation in behaviour that have been documented in natural populations. In the main part of the paper we discuss models for personality differences that (i) explain animal personalities as adaptive behavioural responses to differences in state, (ii) investigate how feedbacks between state and behaviour can stabilize initial differences among individuals and (iii) provide adaptive explanations for animal personalities that are not based on state differences. Throughout, we focus on two basic questions. First, what is the basic conceptual idea underlying the model? Second, what are the key assumptions and predictions of the model? We conclude by discussing empirical features of personalities that have not yet been addressed by formal modelling. While this paper is primarily intended to guide empiricists through current adaptive theory, thereby stimulating empirical tests of these models, we hope it also inspires theoreticians to address aspects of personalities that have received little attention up to now.