scholarly journals Delay in fishery management: diminished yield, longer rebuilding, and increased probability of stock collapse1

2006 ◽  
Vol 64 (1) ◽  
pp. 149-159 ◽  
Author(s):  
Kyle W. Shertzer ◽  
Michael H. Prager
Keyword(s):  
Fishery Management ◽  
Economic Loss ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Short Term ◽  
Stock Status ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Stock Recruitment ◽  
Stock Collapse

Abstract Shertzer, K. W., and Prager, M. H. 2007. Delay in fishery management: diminished yield, longer rebuilding, and increased probability of stock collapse. ICES Journal of Marine Science, 64: 149–159. When a stock is depleted, catch reductions are in order, but typically they are implemented only after considerable delay. Delay occurs because fishery management is political, and stricter management, which involves short-term economic loss, is unpopular. Informed of stock decline, managers often hesitate, perhaps pondering the uncertainty of scientific advice, perhaps hoping that a good year class will render action moot. However, management delay itself can have significant costs, when it exacerbates stock decline. To examine the biological consequences of delay, we simulated a spectrum of fisheries under various degrees of delay in management. Increased delay required larger catch reductions, for more years, to recover benchmark stock status (here, spawning-stock biomass at maximum sustainable yield). Management delay caused stock collapse most often under two conditions: (1) when the stock–recruitment relationship was depensatory, or (2) when catchability, unknown to the assessment, was density-dependent and fishing took juveniles. In contrast, prompt management resulted in quicker recoveries and higher cumulative yields from simulated fisheries. Benefits to stock biomass and fishery yield can be high from implementing management promptly.

scholarly journals Evaluating management strategies to implement the recovery plan for Iberian hake (Merluccius merluccius); the impact of censored catch information

2009 ◽  
Vol 67 (2) ◽  
pp. 258-269 ◽  
Author(s):  
Ernesto Jardim ◽  
Santiago Cerviño ◽  
Manuela Azevedo
Keyword(s):  
Management Strategies ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fishing Mortality ◽  
Merluccius Merluccius ◽  
Total Allowable Catch ◽  
Recovery Plan ◽  
Stock Biomass ◽  
Spawning Stock ◽  
The Impact

Abstract Jardim, E., Cerviño, S., and Azevedo, M. 2010. Evaluating management strategies to implement the recovery plan for Iberian hake (Merluccius merluccius); the impact of censored catch information. – ICES Journal of Marine Science, 67: 258–269. Iberian hake assessment revealed an increase in fishing mortality (F) despite enforcement of a recovery plan. Recent landings exceeded the total allowable catch and discarding rates were high. Alternative management strategies based on F control were evaluated with respect to the probability of recovering spawning-stock biomass (SSB), expected profits, and robustness to uncertainty on catch information and stock dynamics. Results showed that the use of censored catch data, i.e. excluding the Gulf of Cádiz or discards, may lead to inappropriate conclusions. Reducing fishing mortality was necessary for SSB to recover. An Fmax strategy with discard reduction showed the highest probability of rebuilding SSB and led the fishery to sustainable exploitation, with an expected %SPR of 30–40% in 2025, mean individual weight in the landings of 450 g in 2015, and yield increasing by >20%. Because of uncertainty in the estimates of maximum sustainable yield, management strategies based on FMSY were least robust, but all strategies were robust to alternative stock–recruit models.

scholarly journals The estimation of potential yield and stock status using life–history parameters

2005 ◽  
Vol 360 (1453) ◽  
pp. 163-170 ◽  
Author(s):  
J. R. Beddington ◽  
G. P. Kirkwood
Keyword(s):  
Life History ◽  
Growth Parameters ◽  
Maximum Yield ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fishing Mortality ◽  
Potential Yield ◽  
Stock Status ◽  
Fishing Capacity ◽  
Stock Recruitment

Using life–history invariants, this paper develops techniques that allow the estimation of maximum sustainable yield and the fishing mortality rate that produces the maximum yield from estimates of the growth parameters, the length at first capture and the steepness of the stock recruitment relationship. This allows sustainable yields and fishing capacity to be estimated from sparse data, such as those available for developing country fisheries.

scholarly journals Can stock–recruitment points determine which spawning potential ratio is the best proxy for maximum sustainable yield reference points?

2013 ◽  
Vol 70 (6) ◽  
pp. 1075-1080 ◽  
Author(s):  
Christopher M. Legault ◽  
Elizabeth N. Brooks
Keyword(s):  
Life History ◽  
Mortality Rate ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Sustainable Yield ◽  
Marine Science ◽  
Fishing Mortality ◽  
Scatter Plots ◽  
Stock Recruitment ◽  
Spawning Potential Ratio

Abstract Legault, C. M., and Brooks, E. N. 2013. Can stock–recruitment points determine which spawning potential ratio is the best proxy for maximum sustainable yield reference points? – ICES Journal of Marine Science, 70: 1075–1080. The approach of examining scatter plots of stock–recruitment (S–R) estimates to determine appropriate spawning potential ratio (SPR)-based proxies for FMSY was investigated through simulation. As originally proposed, the approach assumed that points above a replacement line indicate year classes that produced a surplus of spawners, while points below that line failed to achieve replacement. In practice, this has been implemented by determining Fmed, the fishing mortality rate that produces a replacement line with 50% of the points above and 50% below the line. A new variation on this approach suggests FMSY proxies can be determined by examining the distribution of S–R points that are above or below replacement lines associated with specific SPRs. Through both analytical calculations and stochastic results, we demonstrate that this approach is fundamentally flawed and that in some cases the inference is diametrically opposed to the method's intended purpose. We reject this approach as a tool for determining FMSY proxies. We recommend that the current proxy of F40% be maintained as appropriate for a typical groundfish life history.

scholarly journals The status of Japanese fisheries relative to fisheries around the world

2017 ◽  
Vol 74 (5) ◽  
pp. 1277-1287 ◽  
Author(s):  
Momoko Ichinokawa ◽  
Hiroshi Okamura ◽  
Hiroyuki Kurota
Keyword(s):  
Maximum Sustainable Yield ◽  
Production Model ◽  
Structured Population Model ◽  
Total Allowable Catch ◽  
Quick Recovery ◽  
Stock Status ◽  
Surplus Production Model ◽  
The Status ◽  
Stock Recruitment ◽  
Age Structured

We present the first quantitative review of the stock status relative to the stock biomass (B) and the exploitation rate (U) that achieved the maximum sustainable yield (MSY) (BMSY and UMSY, respectively) for 37 Japanese stocks contributing 61% of the total marine capture production in Japan. BMSY and UMSY were estimated by assuming three types of stock-recruitment (S-R) relationships and an age-structured population model or by applying a surplus production model. The estimated stock status shows that approximately half of the stocks were overfishing (U/UMSY > 1), and approximately half of the stocks were overfished (B/BMSY < 0.5) during 2011–2013. Over the past 15 years, U decreased and B slightly increased on average. The rate of decrease in the U of the stocks managed by the total allowable catch (TAC) was significantly greater than that of the other stocks, providing evidence of the effectiveness of TAC management in Japan. The above statuses and trends were insensitive to the assumption of the S-R relationship. The characteristics of Japanese stocks composed mainly of resources with relatively high natural mortality, i.e. productivity, suggest that Japanese fisheries have great potential of exhibiting a quick recovery and increasing their yield by adjusting the fishing intensity to an appropriate level.

scholarly journals An explicit solution for calculating optimum spawning stock size from Ricker’s stock recruitment model

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1623 ◽  
Author(s):  
Mark D. Scheuerell
Keyword(s):  
Explicit Solution ◽  
Model Fitting ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Stock Size ◽  
Points Of Interest ◽  
Spawning Stock ◽  
Stock Recruitment ◽  
Explicit Formulae ◽  
Recruitment Model

Stock-recruitment models have been used for decades in fisheries management as a means of formalizing the expected number of offspring that recruit to a fishery based on the number of parents. In particular, Ricker’s stock recruitment model is widely used due to its flexibility and ease with which the parameters can be estimated. After model fitting, the spawning stock size that produces the maximum sustainable yield (SMSY) to a fishery, and the harvest corresponding to it (UMSY), are two of the most common biological reference points of interest to fisheries managers. However, to date there has been no explicit solution for either reference point because of the transcendental nature of the equation needed to solve for them. Therefore, numerical or statistical approximations have been used for more than 30 years. Here I provide explicit formulae for calculating bothSMSYandUMSYin terms of the productivity and density-dependent parameters of Ricker’s model.

scholarly journals The monkfish fishery and its management in the northeastern USA

2008 ◽  
Vol 65 (7) ◽  
pp. 1370-1379 ◽  
Author(s):  
Phil Haring ◽  
J-J. Maguire
Keyword(s):  
Fishery Management ◽  
Management Plan ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Sustainable Yield ◽  
Marine Science ◽  
The Us ◽  
Management Plans ◽  
Northeastern Usa ◽  
Innovative Approaches

Abstract Haring, P., and Maguire, J-J. 2008. The monkfish fishery and its management in the northeastern USA. – ICES Journal of Marine Science, 65: 1370–1379. The domestic monkfish (Lophius americanus) fishery off the northeastern USA is described, along with the management response to the expansion of the fishery and the challenges posed to the management and scientific processes. The US fishery was virtually non-existent in the early 1980s, but it expanded rapidly over the next decade to the point that a management plan became necessary to regulate harvesting. By law, US fishery management plans must include measurable biological reference points based on maximum sustainable yield or a proxy; management plans must stop overfishing and rebuild overfished stocks. For monkfish, the limited biological and historical fisheries information presented significant challenges to science and management and resulted in the adoption of innovative approaches to comply with the law.

Optimal F0.1 Criteria and Their Relationship to Maximum Sustainable Yield

1987 ◽  
Vol 44 (S2) ◽  
pp. s339-s348 ◽  
Author(s):  
R. B. Deriso
Keyword(s):  
Quantitative Relationship ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fish Stocks ◽  
Pacific Halibut ◽  
Western Lake ◽  
Gadus Macrocephalus ◽  
Hippoglossus Stenolepis ◽  
Stock Recruitment ◽  
Yield Per Recruit

There is a unique size of entry into the fishable population that maximizes yield per recruit when an F0.1 fishing criterion is applied to the simple theory of fishing developed by Beverton and Holt in 1957. I define such a pair of parameters (size of entry, F0.1 value) to be the optimal F0.1 criteria and show that they are characterized by the single quantity M/K. A quantitative relationship is established between maximum sustainable yield and the optimal F0.1 criteria for a model population where recruitment is governed by a Ricker stock–recruitment function. This new theory is applied to three fish stocks: Pacific halibut (Hippoglossus stenolepis), western Lake Erie walleye (Stizostedion vitreum vitreum), and Bering Sea Pacific cod (Gadus macrocephalus).

scholarly journals Development of a stock–recruit model for simulating stock dynamics for uncertain situations: the example of Northeast Atlantic mackerel (Scomber scombrus)

2011 ◽  
Vol 68 (5) ◽  
pp. 848-859 ◽  
Author(s):  
E. John Simmonds ◽  
Andrew Campbell ◽  
Dankert Skagen ◽  
Beatriz A. Roel ◽  
Ciaran Kelly
Keyword(s):  
Stock Assessment ◽  
Management Plan ◽  
Maximum Sustainable Yield ◽  
Fish Stock ◽  
Northeast Atlantic ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Functional Forms

Abstract Simmonds, E. J., Campbell, A., Skagen, D., Roel, B. A., and Kelly, C. 2011. Development of a stock–recruit model for simulating stock dynamics for uncertain situations: the example of Northeast Atlantic mackerel (Scomber scombrus). – ICES Journal of Marine Science, 68: 848–859. The assumption of a relationship between recruitment and a spawning stock is the cornerstone of the precautionary approach and may constrain the use of a maximum sustainable yield (MSY) target for fisheries management, because the failure to include such a relationship suggests that providing a measure of stock protection is unnecessary. The implications of fitting different functional forms and stochastic distributions to stock-and-recruit data are investigated. The importance of these considerations is shown by taking a practical example from management: the management plan for Northeast Atlantic mackerel (Scomber scombrus), a fish stock with an average annual catch of 600 000 t. The historical range of spawning-stock biomass is narrow, and historical data from a stock assessment explain only a small proportion of the recruitment variability. We investigate how best to reflect the uncertainty in the stock–recruit relationship. Selecting a single model based on simple statistical criteria can have major consequences for advice and is problematic. Selecting a distribution of models with derived probabilities gives a more complete perception of uncertainty in dynamics. Differences in functional form, distribution of deviations, and variability of coefficients are allowed. The approach appropriately incorporates uncertainty in the stock–recruit relationship for FMSY estimation.

scholarly journals Seabird diets as bioindicators of Atlantic herring recruitment and stock size: a new tool for ecosystem-based fisheries management

2018 ◽  
Vol 75 (8) ◽  
pp. 1215-1229 ◽  
Author(s):  
Lauren C. Scopel ◽  
Antony W. Diamond ◽  
Stephen W. Kress ◽  
Adrian R. Hards ◽  
Paula Shannon
Keyword(s):  
Fishery Management ◽  
Gulf Of Maine ◽  
Clupea Harengus ◽  
Data Series ◽  
Atlantic Herring ◽  
Stock Biomass ◽  
Stock Assessments ◽  
Spawning Stock ◽  
Fishery Data ◽  
Ecosystem Based Fisheries Management

Ecosystem-based fishery management requires understanding of relationships between exploited fish and their predators, such as seabirds. We used exploratory regression analyses to model relationships between Atlantic herring (Clupea harengus) in the diet of seabird chicks at nine nesting colonies in the Gulf of Maine and four types of fishery- and survey-derived herring data. We found several strong relationships, which suggests spatial structuring in herring stocks and likely patterns of herring movements before they recruit into the fishery. Some types of herring data seldom used in stock assessments — notably acoustic surveys, fixed-gear landings, and mass-at-age (i.e., weight-at-age) — correlated as strongly with seabird data as more commonly used series, such as mobile-gear landings and modeled spawning stock biomass. Seabird chick diets collected at specific locations thus offer a promising means to assess the size, distribution, and abundance of juvenile herring across a broad area prior to recruitment, which is a major source of uncertainty in fisheries. Common terns (Sterna hirundo) showed the most potential as a bioindicator, correlating well and showing consistent spatial patterns with 11 of 13 fishery data series.

scholarly journals Assessing causal links in fish stock–recruitment relationships

2017 ◽  
Vol 75 (3) ◽  
pp. 903-911 ◽  
Author(s):  
Maud Pierre ◽  
Tristan Rouyer ◽  
Sylvain Bonhommeau ◽  
J M Fromentin
Keyword(s):  
Time Series ◽  
Dynamical Systems ◽  
Surface Temperature ◽  
Sea Surface ◽  
Fish Stock ◽  
Stochastic Forcing ◽  
Forecasting Methods ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Stock Recruitment

Abstract Understanding whether recruitment fluctuations in fish stock arise from stochastic forcing (e.g. environmental variations) rather than deterministic forces (e.g. intrinsic dynamics) is a long standing question with important applied consequences for fisheries ecology. In particular, the relationship between recruitment, spawning stock biomass and environmental factors is still poorly understood, even though this aspect is crucial for fisheries management. Fisheries data are often short, but arise from complex dynamical systems with a high degree of stochastic forcing, which are difficult to capture through classic modelling approaches. In the present study, recent statistical approaches based on the approximation of the attractors of dynamical systems are applied on a large dataset of time series to assess (i) the directionality of potential causal relationships between recruitment and spawning stock biomass and potential influence of sea-surface temperature on recruitment and (ii) their performance to forecast recruitment. Our study shows that (i) whereas spawning stock biomass and sea surface temperature influence the recruitment to a lesser extent, recruitment causes also parental stock size and (ii) that non-linear forecasting methods performed well for the short-term predictions of recruitment time series. Our results underline that the complex and stochastic nature of the processes characterizing recruitment are unlikely to be captured by classical stock–recruitment relationships, but that non-linear forecasting methods provide interesting perspectives in that respect.

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