Fishing-induced evolution and changing reproductive ecology of fish: the evolution of steepness

2010 ◽  
Vol 67 (10) ◽  
pp. 1708-1719 ◽  
Author(s):  
Katja Enberg ◽  
Christian Jørgensen ◽  
Marc Mangel

Fishing can induce evolutionary changes in individual life history traits, leading to fish that mature smaller and younger and with larger gonads, so that they reproduce more intensely. The steepness of a stock–recruitment relationship is commonly defined as the fraction of recruitment of an unfished population obtained when the spawning stock biomass is 20% of its unfished level. We use a model of harvest-induced evolutionary change to understand how the steepness of the stock–recruitment relationship changes due to fishing. If the true spawning stock biomass is known, the stock–recruitment relationship changes little under fishing-induced evolution and there is little concern for fisheries management. When management is based on a total biomass – recruitment relationship, recruitment may be underestimated, which is also of little concern from a sustainability perspective. However, when the number of spawners – recruitment relationship is used to forecast recruitment, management practice that ignores the evolution of steepness may overestimate recruitment and therefore recommend catches that exceed safe biological limits. Using outdated maturity ogives underestimates spawning stock biomass, which results in steeper and higher stock–recruitment relationships as life histories evolve. Although of little concern for sustainability, this may pose challenges for practical fisheries management.

2020 ◽  
Vol 77 (5) ◽  
pp. 1914-1926
Author(s):  
Simon H Fischer ◽  
José A A De Oliveira ◽  
Laurence T Kell

Abstract Worldwide, the majorities of fish stocks are data-limited and lack fully quantitative stock assessments. Within ICES, such data-limited stocks are currently managed by setting total allowable catch without the use of target reference points. To ensure that such advice is precautionary, we used management strategy evaluation to evaluate an empirical rule that bases catch advice on recent catches, information from a biomass survey index, catch length frequencies, and MSY reference point proxies. Twenty-nine fish stocks were simulated covering a wide range of life histories. The performance of the rule varied substantially between stocks, and the risk of breaching limit reference points was inversely correlated to the von Bertalanffy growth parameter k. Stocks with k>0.32 year−1 had a high probability of stock collapse. A time series cluster analysis revealed four types of dynamics, i.e. groups with similar terminal spawning stock biomass (collapsed, BMSY, 2BMSY, 3BMSY). It was shown that a single generic catch rule cannot be applied across all life histories, and management should instead be linked to life-history traits, and in particular, the nature of the time series of stock metrics. The lessons learnt can help future work to shape scientific research into data-limited fisheries management and to ensure that fisheries are MSY compliant and precautionary.


2005 ◽  
Vol 62 (4) ◽  
pp. 725-729 ◽  
Author(s):  
Brian J Shuter ◽  
Peter A Abrams

Throughout his career, Ray Beverton displayed an interest in the life history diversity in marine and freshwater fish. The papers collected here describe recent research directed at documenting this diversity and understanding both its consequences and the processes that generate it. There are three themes: factors that direct life history dynamics; fishing as a force that redirects life history dynamics; and roles for life history statics in conservation management. The "dynamics" papers show that fish life histories can evolve in response to both natural and harvest-induced selective pressures. Evolution in response to harvesting can be rapid, with potentially dramatic effects on population dynamics and sustainable exploitation. The "statics" articles demonstrate how maturity traits combine with shifts in habitat use to shape the sensitivity of a population to habitat loss. Life history shifts can dramatically alter the safety of harvesting policies that were prudent in the past; shifts of the predators or prey of a harvested species can be as important as shifts in the harvested species itself. Further work on the ecological circumstances that favour different degrees of plastic or genetic life history responses to human impacts are needed to prevent inadvertent induction of long-lasing evolutionary changes in fish life histories.


Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.


Author(s):  
Jeffrey A. Hutchings

Life histories describe how genotypes schedule their reproductive effort throughout life in response to factors that affect their survival and fecundity. Life histories are solutions that selection has produced to solve the problem of how to persist in a given environment. These solutions differ tremendously within and among species. Some organisms mature within months of attaining life, others within decades; some produce few, large offspring as opposed to numerous, small offspring; some reproduce many times throughout their lives while others die after reproducing just once. The exponential pace of life-history research provides an opportune time to engage and re-engage new generations of students and researchers on the fundamentals and applications of life-history theory. Chapters 1 through 4 describe the fundamentals of life-history theory. Chapters 5 through 8 focus on the evolution of life-history traits. Chapters 9 and 10 summarize how life-history theory and prediction has been applied within the contexts of conservation and sustainable exploitation. This primer offers an effective means of rendering the topic accessible to readers from a broad range of academic experience and research expertise.


The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Robert E. Ricklefs

Abstract Although we have learned much about avian life histories during the 50 years since the seminal publications of David Lack, Alexander Skutch, and Reginald Moreau, we still do not have adequate explanations for some of the basic patterns of variation in life-history traits among birds. In part, this reflects two consequences of the predominance of evolutionary ecology thinking during the past three decades. First, by blurring the distinction between life-history traits and life-table variables, we have tended to divorce life histories from their environmental context, which forms the link between the life history and the life table. Second, by emphasizing constrained evolutionary responses to selective factors, we have set aside alternative explanations for observed correlations among life-history traits and life-table variables. Density-dependent feedback and independent evolutionary response to correlated aspects of the environment also may link traits through different mechanisms. Additionally, in some cases we have failed to evaluate quantitatively ideas that are compelling qualitatively, ignored or explained away relevant empirical data, and neglected logical implications of certain compelling ideas. Comparative analysis of avian life histories shows that species are distributed along a dominant slow-fast axis. Furthermore, among birds, annual reproductive rate and adult mortality are directly proportional to each other, requiring that pre-reproductive survival is approximately constant. This further implies that age at maturity increases dramatically with increasing adult survival rate. The significance of these correlations is obscure, particularly because survival and reproductive rates at each age include the effects of many life-history traits. For example, reproductive rate is determined by clutch size, nesting success, season length, and nest-cycle length, each of which represents the outcome of many different interactions of an individual's life-history traits with its environment. Resolution of the most basic issues raised by patterns of life histories clearly will require innovative empirical, modeling, and experimental approaches. However, the most fundamental change required at this time is a broadening of the evolutionary ecology paradigm to include a variety of alternative mechanisms for generating patterns of life-history variation.


1988 ◽  
Vol 66 (8) ◽  
pp. 1906-1912 ◽  
Author(s):  
Todd W. Arnold

Recently, Zammuto (R. M. Zammuto. 1986. Can. J. Zool. 64: 2739–2749) suggested that North American game birds exhibited survival–fecundity trade-offs consistent with the "cost of reproduction" hypothesis. However, there were four serious problems with the data and the analyses that Zammuto used: (i) the species chosen for analysis ("game birds") showed little taxonomic or ecological uniformity, (ii) the measures of future reproductive value (maximum longevity) were severely biased by unequal sample sizes of band recoveries, (iii) the measures of current reproductive effort (clutch sizes) were inappropriate given that most of the birds analyzed produce self-feeding precocial offspring, and (iv) the statistical units used in the majority of analyses (species) were not statistically independent with respect to higher level taxonomy. After correcting these problems, I found little evidence of survival–fecundity trade-offs among precocial game birds, and I attribute most of the explainable variation in life-history traits of these birds to allometry, phylogeny, and geography.


2015 ◽  
Vol 27 (4) ◽  
pp. 333-340 ◽  
Author(s):  
Stuart Hanchet ◽  
Keith Sainsbury ◽  
Doug Butterworth ◽  
Chris Darby ◽  
Viacheslav Bizikov ◽  
...  

AbstractSeveral recent papers have criticized the scientific robustness of the fisheries management system used by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), including that for Ross Sea toothfish. Here we present a response from the wider CCAMLR community to address concerns and to correct some apparent misconceptions about how CCAMLR acts to promote conservation whilst allowing safe exploitation in all of its fisheries. A key aspect of CCAMLR’s approach is its adaptive feedback nature; regular monitoring and analysis allows for adjustments to be made, as necessary, to provide a robust management system despite the statistical uncertainties inherent in any single assessment. Within the Ross Sea, application of CCAMLR’s precautionary approach has allowed the toothfish fishery to develop in a steady fashion with an associated accumulation of data and greater scientific understanding. Regular stock assessments of the fishery have been carried out since 2005, and the 2013 stock assessment estimated current spawning stock biomass to be at 75% of the pre-exploitation level. There will always be additional uncertainties which need to be addressed, but where information is lacking the CCAMLR approach to management ensures exploitation rates are at a level commensurate with a precautionary approach.


1996 ◽  
Vol 351 (1345) ◽  
pp. 1341-1348 ◽  

Several empirical models have attempted to account for the covariation among life history traits observed in a variety of organisms. One of these models, the fast-slow continuum hypothesis, emphasizes the role played by mortality at different stages of the life cycle in shaping the large array of life history variation. Under this scheme, species can be arranged from those suffering high adult mortality levels to those undergoing relatively low adult mortality. This differential mortality is responsible for the evolution of contrasting life histories on either end of the continuum. Species undergoing high adult mortality are expected to have shorter life cycles, faster development rates and higher fecundity than those experiencing lower adult mortality. The theory has proved accurate in describing the evolution of life histories in several animal groups but has previously not been tested in plants. Here we test this theory using demographic information for 83 species of perennial plants. In accordance with the fast-slow continuum, plants undergoing high adult mortality have shorter lifespans and reach sexual maturity at an earlier age. However, demographic traits related to reproduction (the intrinsic rate of natural increase, the net reproductive rate and the average rate of decrease in the intensity of natural selection on fecundity) do not show the covariation expected with longevity, age at first reproducion and life expectancy at sexual maturity. Contrary to the situation in animals, plants with multiple meristems continuously increase their size and, consequently, their fecundity and reproductive value. This may balance the negative effect of mortality on fitness, thus having no apparent effect in the sign of the covariation between these two goups of life history traits.


Parasitology ◽  
1998 ◽  
Vol 116 (S1) ◽  
pp. S47-S55 ◽  
Author(s):  
J. C. Koella ◽  
P. Agnew ◽  
Y. Michalakis

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.


2014 ◽  
Vol 281 (1782) ◽  
pp. 20132458 ◽  
Author(s):  
Eli M. Swanson ◽  
Ben Dantzer

Despite the diversity of mammalian life histories, persistent patterns of covariation have been identified, such as the ‘fast–slow’ axis of life-history covariation. Smaller species generally exhibit ‘faster’ life histories, developing and reproducing rapidly, but dying young. Hormonal mechanisms with pleiotropic effects may mediate such broad patterns of life-history variation. Insulin-like growth factor 1 (IGF-1) is one such mechanism because heightened IGF-1 activity is related to traits associated with faster life histories, such as increased growth and reproduction, but decreased lifespan. Using comparative methods, we show that among 41 mammalian species, increased plasma IGF-1 concentrations are associated with fast life histories and altricial reproductive patterns. Interspecific path analyses show that the effects of IGF-1 on these broad patterns of life-history variation are through its direct effects on some individual life-history traits (adult body size, growth rate, basal metabolic rate) and through its indirect effects on the remaining life-history traits. Our results suggest that the role of IGF-1 as a mechanism mediating life-history variation is conserved over the evolutionary time period defining mammalian diversification, that hormone–trait linkages can evolve as a unit, and that suites of life-history traits could be adjusted in response to selection through changes in plasma IGF-1.


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