scholarly journals Linking the performance of a data-limited empirical catch rule to life-history traits

2020 ◽  
Vol 77 (5) ◽  
pp. 1914-1926
Author(s):  
Simon H Fischer ◽  
José A A De Oliveira ◽  
Laurence T Kell
Keyword(s):  
Time Series ◽  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Growth Parameter ◽  
Reference Points ◽  
Total Allowable Catch ◽  
Fish Stocks ◽  
Wide Range ◽  
Spawning Stock

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.

scholarly journals Population declines of tuna and relatives depend on their speed of life

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150322 ◽  
Author(s):  
M. J. Juan-Jordá ◽  
I. Mosqueira ◽  
J. Freire ◽  
N. K. Dulvy
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Population Level ◽  
Maximum Size ◽  
Latitudinal Gradients ◽  
Fishing Mortality ◽  
Population Declines ◽  
Wide Range ◽  
Exploitation Status

Larger-bodied species in a wide range of taxonomic groups including mammals, fishes and birds tend to decline more steeply and are at greater risk of extinction. Yet, the diversity in life histories is governed not only by body size, but also by time-related traits. A key question is whether this size-dependency of vulnerability also holds, not just locally, but globally across a wider range of environments. We test the relative importance of size- and time-related life-history traits and fishing mortality in determining population declines and current exploitation status in tunas and their relatives. We use high-quality datasets of half a century of population trajectories combined with population-level fishing mortalities and life-history traits. Time-related traits (e.g. growth rate), rather than size-related traits (e.g. maximum size), better explain the extent and rate of declines and current exploitation status across tuna assemblages, after controlling for fishing mortality. Consequently, there is strong geographical patterning in population declines, such that populations with slower life histories (found at higher cooler latitudes) have declined most and more steeply and have a higher probability of being overfished than populations with faster life histories (found at tropical latitudes). Hence, the strong, temperature-driven, latitudinal gradients in life-history traits may underlie the global patterning of population declines, fisheries collapses and local extinctions.

Modelling fishing-induced adaptations and consequences for natural mortality

2010 ◽  
Vol 67 (7) ◽  
pp. 1086-1097 ◽  
Author(s):  
Christian Jørgensen ◽  
Øyvind Fiksen
Keyword(s):  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Life History Traits ◽  
Reproductive Behaviour ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Trade Offs ◽  
Wide Range ◽  
Investment In Reproduction

When trade-offs involving predation and mortality are perturbed by human activities, behaviour and life histories are expected to change, with consequences for natural mortality rates. We present a general life history model for fish in which three common relationships link natural mortality to life history traits and behaviour. First, survival increases with body size. Second, survival declines with growth rate due to risks involved with resource acquisition and allocation. Third, fish that invest heavily in reproduction suffer from decreased survival due to costly reproductive behaviour or morphology that makes escapes from predators less successful. The model predicts increased natural mortality rate as an adaptive response to harvesting. This extends previous models that have shown that harvesting may cause smaller body size, higher growth rates, and higher investment in reproduction. The predicted increase in natural mortality is roughly half the fishing mortality over a wide range of harvest levels and parameter combinations such that fishing two fish kills three after evolutionary adaptations have taken place.

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
Keyword(s):  
Life History ◽  
Fisheries Management ◽  
Life Histories ◽  
Life History Traits ◽  
Management Practice ◽  
Total Biomass ◽  
Evolutionary Changes ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Stock Recruitment

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.

scholarly journals Self-starting cumulative sum harvest control rule (SS-CUSUM-HCR) for status-quo management of data-limited fisheries

2016 ◽  
Vol 73 (3) ◽  
pp. 366-381 ◽  
Author(s):  
Deepak George Pazhayamadom ◽  
Ciarán J. Kelly ◽  
Emer Rogan ◽  
Edward A. Codling
Keyword(s):  
Time Series ◽  
Temporal Trends ◽  
Status Quo ◽  
Reference Points ◽  
Fish Stock ◽  
Cumulative Sum ◽  
Total Allowable Catch ◽  
Control Rule ◽  
Wide Range ◽  
Harvest Control Rule

We demonstrate a harvest control rule based on the self-starting cumulative sum (SS-CUSUM) control chart that can maintain a fish stock at its starting (status-quo) level. The SS-CUSUM is an indicator monitoring tool commonly used in quality control engineering and does not require a long time series or predefined reference point for detecting temporal trends. The reference points in SS-CUSUM are calibrated in the form of running means that are updated on an ongoing basis when new observations become available. The SS-CUSUM can be initiated with as few as two observations in the time series and can be applied long before many other methods, soon after initial data become available. A wide range of stock indicators can be monitored, but in this study, we demonstrate the method using an equally weighted sum of two indicators: a recruitment indicator and a large fish indicator from a simulated fishery. We assume that no life history data are available other than 2 years of both indicator data and current harvest levels when the SS-CUSUM initiates. The signals generated from SS-CUSUM trigger a harvest control rule (SS-CUSUM-HCR), where the shift that occurs in the indicator time series is computed and is used as an adjustment factor for updating the total allowable catch. Our study shows that the SS-CUSUM-HCR can maintain the fish stock at its starting status-quo level (even for overfished initial states) but has limited scope if the fishery is already in an undesirable state such as a stock collapse. We discuss how the SS-CUSUM approach could be adapted to move beyond a status-quo management strategy, if additional information on the desirable state of the fishery is available.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

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.

scholarly journals Quirky patterns in time-series of estimates of recruitment could be artefacts

2014 ◽  
Vol 72 (1) ◽  
pp. 111-116 ◽  
Author(s):  
M. Dickey-Collas ◽  
N. T. Hintzen ◽  
R. D. M. Nash ◽  
P-J. Schön ◽  
M. R. Payne
Keyword(s):  
Time Series ◽  
Stock Assessment ◽  
Meta Analysis ◽  
Reference Points ◽  
Fish Stocks ◽  
Stock Recruitment ◽  
Modelling Assumptions ◽  
Meta Analyses ◽  
Recruitment Model ◽  
Recruitment Time

Abstract The accessibility of databases of global or regional stock assessment outputs is leading to an increase in meta-analysis of the dynamics of fish stocks. In most of these analyses, each of the time-series is generally assumed to be directly comparable. However, the approach to stock assessment employed, and the associated modelling assumptions, can have an important influence on the characteristics of each time-series. We explore this idea by investigating recruitment time-series with three different recruitment parameterizations: a stock–recruitment model, a random-walk time-series model, and non-parametric “free” estimation of recruitment. We show that the recruitment time-series is sensitive to model assumptions and this can impact reference points in management, the perception of variability in recruitment and thus undermine meta-analyses. The assumption of the direct comparability of recruitment time-series in databases is therefore not consistent across or within species and stocks. Caution is therefore required as perhaps the characteristics of the time-series of stock dynamics may be determined by the model used to generate them, rather than underlying ecological phenomena. This is especially true when information about cohort abundance is noisy or lacking.

A Primer of Life Histories

2021 ◽  
Author(s):  
Jeffrey A. Hutchings
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Theory ◽  
Life History Traits ◽  
Reproductive Effort ◽  
Effective Means ◽  
Academic Experience ◽  
Sustainable Exploitation ◽  
Evolution Of Life ◽  
Opportune Time

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.

scholarly journals Early swelling response to phytohemagglutinin is lower in older toads

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6104 ◽  
Author(s):  
Francisco Javier Zamora-Camacho ◽  
Mar Comas
Keyword(s):  
Immune Response ◽  
Time Series ◽  
Life History ◽  
Life History Traits ◽  
Area Under The Curve ◽  
Older Individuals ◽  
Innate Response ◽  
Early Immune Response ◽  
The Individual ◽  
Epidalea Calamita

The effects of age on performance of life-history traits are diverse, but a common outcome is senescence, an irreversible deterioration of physical and physiological capabilities of older individuals. Immune response is potentially bound to senescence. However, little is known about immune response ageing in amphibians. In this work, we test the hypothesis that amphibian early immune response is reduced in older individuals. To this end, we captured adult natterjack toads (Epidalea calamita) and inoculated them with phytohemagglutinin, an innocuous protein that triggers a skin-swelling immune response whose magnitude is directly proportional to the ability of the individual to mount an immune response. We measured early swelling immune response (corresponding to an innate-response stage) hourly, for six hours, and we calculated the area under the curve (AUC) for each individual’s time series, as a measure of immune response magnitude incorporating time. We estimated toad age by means of phalanx skeletochronology. Swelling and AUC decreased with age. Therefore, in accordance with our predictions, early immune response seems subject to senescence in these toads. Reduced ability to get over infections due to senescence of immune respose might be—together with a worse functioning of other organs and systems—among the causes of lower survival of older specimens.

scholarly journals Population variability under stressors is dependent on body mass growth and asymptotic body size

2020 ◽  
Vol 7 (2) ◽  
pp. 192011
Author(s):  
Leonie Färber ◽  
Rob van Gemert ◽  
Øystein Langangen ◽  
Joël M. Durant ◽  
Ken H. Andersen
Keyword(s):  
Body Mass ◽  
Life Histories ◽  
Random Noise ◽  
Fish Stock ◽  
Vital Rates ◽  
Anthropogenic Pressures ◽  
Fish Stocks ◽  
Asymptotic Size ◽  
Wide Range ◽  
Stock Recruitment

The recruitment and biomass of a fish stock are influenced by their environmental conditions and anthropogenic pressures such as fishing. The variability in the environment often translates into fluctuations in recruitment, which then propagate throughout the stock biomass. In order to manage fish stocks sustainably, it is necessary to understand their dynamics. Here, we systematically explore the dynamics and sensitivity of fish stock recruitment and biomass to environmental noise. Using an age-structured and trait-based model, we explore random noise (white noise) and autocorrelated noise (red noise) in combination with low to high levels of harvesting. We determine the vital rates of stocks covering a wide range of possible body mass (size) growth rates and asymptotic size parameter combinations. Our study indicates that the variability of stock recruitment and biomass are probably correlated with the stock's asymptotic size and growth rate. We find that fast-growing and large-sized fish stocks are likely to be less vulnerable to disturbances than slow-growing and small-sized fish stocks. We show how the natural variability in fish stocks is amplified by fishing, not just for one stock but for a broad range of fish life histories.

scholarly journals Density Dependence, Evolutionary Optimization, and the Diversification of Avian Life Histories

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Robert E. Ricklefs
Keyword(s):  
Life History ◽  
Life Table ◽  
Life Histories ◽  
Life History Traits ◽  
Evolutionary Ecology ◽  
Reproductive Rate ◽  
Empirical Modeling ◽  
Adult Survival ◽  
Life History Variation ◽  
Evolutionary Response

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.

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