scholarly journals Reproductive hyperallometry and managing the world’s fisheries

2021 ◽  
Vol 118 (34) ◽  
pp. e2100695118
Author(s):  
Dustin J. Marshall ◽  
Michael Bode ◽  
Marc Mangel ◽  
Robert Arlinghaus ◽  
E. J. Dick
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Reference Points ◽  
Target Level ◽  
Fish Stocks ◽  
Global Food Security ◽  
Common Reference ◽  
Future Assessment ◽  
Traditional Approaches ◽  
Global Food

Marine fisheries are an essential component of global food security, but many are close to their limits and some are overfished. The models that guide the management of these fisheries almost always assume reproduction is proportional to mass (isometry), when fecundity generally increases disproportionately to mass (hyperallometry). Judged against several management reference points, we show that assuming isometry overestimates the replenishment potential of exploited fish stocks by 22% (range: 2% to 78%) for 32 of the world’s largest fisheries, risking systematic overharvesting. We calculate that target catches based on assumptions of isometry are more than double those based on assumptions of hyperallometry for most species, such that common reference points are set twice as high as they should be to maintain the target level of replenishment. We also show that hyperallometric reproduction provides opportunities for increasing the efficacy of tools that are underused in standard fisheries management, such as protected areas or harvest slot limits. Adopting management strategies that conserve large, hyperfecund fish may, in some instances, result in higher yields relative to traditional approaches. We recommend that future assessment of reference points and quotas include reproductive hyperallometry unless there is clear evidence that it does not occur in that species.

A Bayesian spatiotemporal approach to inform management unit appropriateness

2019 ◽  
Vol 76 (2) ◽  
pp. 217-237 ◽  
Author(s):  
Rujia Bi ◽  
Yan Jiao ◽  
Can Zhou ◽  
Eric Hallerman
Keyword(s):  
Great Lakes ◽  
Fisheries Management ◽  
Yellow Perch ◽  
Management Strategies ◽  
Computational Cost ◽  
Bayesian Hierarchical ◽  
Fish Stocks ◽  
Spatiotemporal Correlation ◽  
Management Actions ◽  
Gill Net

One prerequisite for sustainable fisheries management is to match management actions with biological processes. Stocks are fundamental units for fisheries management. Understanding the spatial structure of fish stocks is critical for conducting defensible stock assessments, applying efficient management strategies, and ensuring the sustainability of fish stocks. Yellow perch (Perca flavescens) is an important fishery in the Great Lakes. The appropriateness of its management units (MUs) has been identified as of high concern by the Great Lakes Fisheries Commission. Here we established integrated nested Laplace approximations and stochastic partial differential equations as two powerful tools for modeling spatiotemporal patterns of fish relative biomass. These fast computational approaches were applied to fit a Bayesian hierarchical hurdle model to occurrence and positive mass of yellow perch caught in gill-net surveys. Yellow perch relative biomass index has clear temporal variation and spatial heterogeneity, with the two middle MUs for yellow perch within Lake Erie merging together. The method explicitly models the spatiotemporal correlation structure inherent in biomass survey data at a reasonable computational cost, and the estimated spatiotemporal correlation informs stock structure.

scholarly journals Ecosystem-based reference points under varying plankton productivity states and fisheries management strategies

2019 ◽  
Vol 76 (7) ◽  
pp. 2045-2059 ◽  
Author(s):  
Chuanbo Guo ◽  
Caihong Fu ◽  
Robyn E Forrest ◽  
Norm Olsen ◽  
Huizhu Liu ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Reference Points ◽  
Productivity Change ◽  
Pacific Herring ◽  
Fishing Mortality ◽  
Pacific Cod ◽  
Sustainable Fisheries ◽  
Ecosystem Effects ◽  
Plankton Biomass

Abstract In the context of ecosystem-based fisheries management, which should consider changing and uncertain environmental conditions, the development of ecosystem-based biological reference points (EBRPs) to account for important multi-species (MS) interactions, fishery operations, and climate change, is of paramount importance for sustainable fisheries management. However, EBRPs under varying plankton productivity states and fisheries management strategies are seldom developed, and the ecosystem effects of these changes are still largely unknown. In this study, ecosystem-based FMSY (fishing mortality rate at MSY) values were estimated within an end-to-end ecosystem model (OSMOSE) for three focused fish species (Pacific Herring, Clupea pallasii; Pacific Cod, Gadus macrocephalus; Lingcod, Ophiodon elongatus) under three plankton productivity states of differing plankton biomass at high, current, and low levels. In addition, ecosystem effects were compared across different plankton productivity and fisheries management strategies with the latter consisting of two fishery scenarios (i.e. single-species-focused (SS) and MS-focused), various fishing mortality rates, and two harvest policies (with and without harvest control rules, HCRs). Main findings of this study include: (i) plankton productivity change affected the values of ecosystem-based FMSY, which increased as plankton productivity states changed from low to high plankton biomass; (ii) ecosystem-based FMSY for Pacific Herring and Pacific Cod stocks increased when fishery scenarios shifted from SS-focused to MS-focused; (iii) fisheries management incorporating HCR yielded more stable system catch and system biomass; and (iv) high plankton biomass combined with fisheries management using HCR could maintain stable ecosystem production and sustainable fisheries. Based on our findings, we highlight possible adaptive fisheries management strategies in the face of future climate and ocean changes. Overall, EBRPs complement SS stock assessments by incorporating key ecological processes and ecosystem properties, thus providing supporting evidence for better incorporation of ecosystem considerations into scientific advice for sustainable fisheries management.

scholarly journals Zebrafish IL-4-like cytokines and IL-10 suppress inflammation but only IL-10 is essential for gill homeostasis

2020 ◽  
Author(s):  
Federica Bottiglione ◽  
Christopher T. Dee ◽  
Robert Lea ◽  
Leo Zeef ◽  
Andrew P. Badrock ◽  
...  
Keyword(s):  
Immune Response ◽  
Food Security ◽  
Loss Of Function ◽  
Fish Health ◽  
Fish Stocks ◽  
Global Food Security ◽  
Mucosal Surfaces ◽  
Anti Inflammatory ◽  
Open Question ◽  
Global Food

AbstractHealthy fish stocks are central to global food security. Key to fish health is robust immunity at mucosal surfaces, and especially at the gills. However, a balance must be struck between tolerating commensal microorganisms and reacting appropriately toward pathogens. In mammals, IL-4 and IL-13 in concert with IL-10 are essential for balancing immune response to pathogens and suppressing inflammation. Whether their fish counterparts perform similar roles is an open question. Here, we have generated IL-4/13A and IL-4/13B mutant zebrafish and, together with existing IL-10 mutants, characterized the consequences of loss-of-function of these cytokines. We demonstrate that these cytokines are required to suppress inflammation. Further, IL-4/13A and IL-4/13B are required for the maintenance of a Th2-like phenotype in the gills. As in mammals, IL-10 appears to have a more striking anti-inflammatory function than IL-4-like cytokines. Thus, both IL-10 and IL-4/13 paralogues in zebrafish exhibit aspects of conserved function with their mammalian counterparts.

Nothing as Practical as a Good Theory

2019 ◽  
pp. 1-12
Author(s):  
Ken H. Andersen
Keyword(s):  
Fisheries Management ◽  
Fish Communities ◽  
Reference Points ◽  
Fish Ecology ◽  
Good Theory ◽  
Fish Stocks ◽  
Fisheries Science ◽  
Ecosystem Based Fisheries Management ◽  
Stock Recovery

This chapter provides some context on the overall themes and theory of this volume. Throughout, the theory is applied to relevant problems in fisheries science: impact of fishing on demography, fisheries reference points, evolutionary impact assessments, stock recovery, ecosystem-based fisheries management, and so on, as well as to basic ecological and evolutionary questions. The chapter begins by addressing the motivations for a new theory of fish stocks and fish communities. It also considers what problems such a theory should address and how such a theory can be formulated. From here, the chapter discusses what makes a good theory and the peculiar challenges fish ecology represents.

scholarly journals Consequences of growth variation in northern Baltic herring for assessment and management

2004 ◽  
Vol 61 (3) ◽  
pp. 338-350 ◽  
Author(s):  
Mika Rahikainen ◽  
Robert L. Stephenson
Keyword(s):  
Baltic Sea ◽  
Stock Assessment ◽  
Management Strategies ◽  
Reference Points ◽  
Common Reference ◽  
Baltic Herring ◽  
Marked Variability ◽  
Growth Variation ◽  
Definition Of ◽  
The Impact

Abstract Growth rates of herring in the northern Baltic Sea differ among areas, and have changed substantially over time in some areas in response to environmental change. Weight-at-age of adult herring in some areas of the Finnish herring fishery fluctuated by as much as 60% over the past three decades. Elsewhere, there have been similar but more subtle changes. Growth variation has implications for stock assessment and management: differences suggest a need for considering a smaller spatial structure, at least at the scale of the ICES subdivision, in the case of northern Baltic herring. Changes in growth have an impact on the calculation and use of common biological reference points, and erode the capability of yield projections beyond the short term. Investigation of the impact of growth variation on common reference points of northern Baltic herring revealed that F0.1 was a robust reference despite the marked variability in growth, whereas Fx%SPR (e.g. F35%SPR) was less robust, depending on the definition of maximum spawning-per-recruit. Herring in different areas of the northern Baltic Sea probably require different reference points and possibly different management strategies, as a consequence of differences and variability in growth characteristics.

Recent international agreements and the precautionary approach: new directions for fisheries management science

1998 ◽  
Vol 55 (6) ◽  
pp. 1545-1552 ◽  
Author(s):  
Laura J Richards ◽  
Jean-Jacques Maguire
Keyword(s):  
Fisheries Management ◽  
Scientific Information ◽  
Decision Rules ◽  
International Agreements ◽  
Reference Points ◽  
Future Research ◽  
Specific Reference ◽  
Precautionary Approach ◽  
Ecosystem Impacts ◽  
Fish Stocks

The dynamics of exploited fish populations can be highly uncertain and the precautionary approach to fisheries management addresses such uncertainties. The precautionary approach is now embodied in several international agreements, including (i) the UN Straddling Fish Stocks and Highly Migratory Fish Stocks Agreement and (ii) the FAO Code of Conduct. We discuss how application of these agreements will change the daily operations of many fisheries agencies. Contrary to past practices, the absence of adequate scientific information can no longer be a reason for postponing or failing to take conservation measures. Future harvest strategies will be based on stock-specific reference points and predefined decision rules. However, more research is required to quantify uncertainties associated with reference point definitions and their practical application in a management context. In addition, future research will emphasize environmental issues with extensive data requirements, such as ecosystem impacts of fishing. Data collection will remain a core business activity; agencies must address the costs of maintaining shared and documented data archives over the long term.

A Robust Approach to Equilibrium Yield Curves

1986 ◽  
Vol 43 (7) ◽  
pp. 1332-1339 ◽  
Author(s):  
Gilbert G. Walter
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Real Data ◽  
Concave Function ◽  
Fishing Effort ◽  
Approach To Equilibrium ◽  
Yield Curves ◽  
Fish Stocks ◽  
Robust Approach ◽  
Equilibrium Yield

The surplus yield models of fisheries management usually assume that a concave function of equilibrium yield versus fishing effort exists. However, this function is notoriously difficult to fit to real data for a number of reasons, including the fact that few fisheries are in equilibrium. A procedure for obtaining rough estimates of these equilibrium curves is introduced. Management strategies based on these estimates and the annual yield curves are also presented. The procedures are then applied to several fish stocks.

scholarly journals Status and targets for rebuilding the three major fish stocks in Lake Victoria

2020 ◽  
Author(s):  
Laban Musinguzi ◽  
Mark Olokotum ◽  
Vianny Natugonza
Keyword(s):  
Fisheries Management ◽  
Nile Tilapia ◽  
Lake Victoria ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Nile Perch ◽  
Fish Stocks ◽  
Illegal Fishing ◽  
Stock Status ◽  
Low Levels

AbstractWe determined fisheries management reference points for three major fish stocks in Lake Victoria (Nile tilapia, Nile perch and Dagaa) for Uganda and the whole lake. The aim was to ascertain stock status and define reasonable objectives and targets for rebuilding to sustainable levels. Dagaa was found to be healthy in Uganda and the whole lake but tending to overfished status. In Uganda, the stock status of Nile tilapia and Nile perch was recruitment impaired but tending more towards collapsed and overfished status respectively. In the whole lake, the stock status of Nile tilapia and Nile perch was collapsed and overfished respectively with the latter tending more towards recruitment impaired. Estimates of maximum sustainable yield (MSY) showed that catches could be increased under good management. Rebuilding the Nile tilapia and Nile perch stock biomasses to MSY level (Bmsy) could respectively increase the catches above the current level by 9.2% and 29.5% in Uganda and by 72.8% and 15.1% in the whole lake. The immediate objective for fisheries management should be to rebuild biomass for the Nile tilapia and Nile perch stocks to Bmsy. Elimination of illegal fishing practices has proved to be effective. In addition, management needs to keep catches at low levels until biomass for the stocks is ≥Bmsy for at least three consecutive years.

Introduction

2020 ◽  
pp. 1-12
Author(s):  
Michael J. Fogarty ◽  
Jeremy S. Collie
Keyword(s):  
Fisheries Management ◽  
Fishery Management ◽  
Stable States ◽  
Alternate Stable States ◽  
Linear Dynamics ◽  
Global Food Security ◽  
The World ◽  
History Of ◽  
Global Food ◽  
Empirical Record

Fisheries provide critical contributions to global food security and are important in the fabric of human societies throughout the world. This chapter provides a brief history of fishery development and the evolution of scientific understanding and approaches so critical to effective fisheries management. It shows how processes at the population, community, and ecosystem levels are manifest in complex ways in even simple descriptors such as catch histories. Although many aspects of conventional fisheries management center on equilibrium concepts, the empirical record suggests a much more complex reality with the possibility of alternate stable states and non-linear dynamics. This chapter provides the motivation for exploring alternative models of fishery dynamics in a broader ecological context. Confronting complexity is essential if we are to move toward operational Ecosystem-based Fishery Management on a global basis.

scholarly journals Applying bayesian population assessment models to artisanal, multispecies fisheries in the Northern Mokran Sea, Iran

2018 ◽  
Vol 28 ◽  
pp. 61-89
Author(s):  
Abdul Rashid Jamnia ◽  
Ahmad Ali Keikha ◽  
Mahmoud Ahmadpour ◽  
Abdoul Ahad Cissé ◽  
Mohammad Rokouei
Keyword(s):  
Fisheries Management ◽  
Stock Assessment ◽  
Bayesian Models ◽  
Management Strategies ◽  
Demersal Fish ◽  
Reference Points ◽  
Small Scale ◽  
Parameter Estimates ◽  
Multiple Sources ◽  
Small Scale Fisheries

Small-scale fisheries substantially contribute to the reduction of poverty, local economies and food safety in many countries. However, limited and low-quality catches and effort data for small-scale fisheries complicate the stock assessment and management. Bayesian modelling has been advocated when assessing fisheries with limited data. Specifically, Bayesian models can incorporate information of the multiple sources, improve precision in the stock assessments and provide specific levels of uncertainty for estimating the relevant parameters. In this study, therefore, the state-space Bayesian generalised surplus production models will be used in order to estimate the stock status of fourteen Demersal fish species targeted by small-scale fisheries in Sistan and Baluchestan, Iran. The model was estimated using Markov chain Monte Carlo (MCMC) and Gibbs Sampling. Model parameter estimates were evaluated by the formal convergence and stationarity diagnostic tests, indicating convergence and accuracy. They were also aligned with existing parameter estimates for fourteen species of the other locations. This suggests model reliability and demonstrates the utility of Bayesian models. According to estimated fisheries’ management reference points, all assessed fish stocks appear to be overfished. Overfishing considered, the current fisheries management strategies for the small-scale fisheries may need some adjustments to warrant the long-term viability of the fisheries.

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