AZOV SEA VIMBA INDICATOR ASSESSMENT OF THE STATE OF FISH POPULATION IN TERMS OF LACK OF BIOLOGICAL DATA BY LBI MODEL

Fisheries ◽  
2021 ◽  
Vol 2021 (3) ◽  
pp. 68-75
Author(s):  
Inna Kozobrod ◽  
M. Pyatinsky ◽  
Elena Vlasenko
Keyword(s):  
Stock Assessment ◽  
Fish Population ◽  
Maximum Sustainable Yield ◽  
Biological Data ◽  
Reference Points ◽  
Population Characteristics ◽  
Small Scale ◽  
Assessment Procedure ◽  
Indicator Method ◽  
Yield Level

Stock assessment of vimba population Vimba vimba (Linnaeus, 1758) in period 2015–2020 was performed by qualitative indicator method LBI (Length-Based Indicators) that allows to assess qualitative characteristics of the population and fisheries and MSY biological reference points. The indicator, qualitative approach to stock assessment was applied due to absence vimba population of stable stock-recruitment relationship (due to artificial reproduction exist), which makes impossible to apply surplus production approach to solve production equation dB/dt. LBI model was performed based on available length-weight vimba frequencies dynamics information, which allows to evaluate qualitative population characteristics and fisheries impact. Model results shows no overexploitation signals: in period 2015–2020 fisheries are carried out in maximum sustainable yield level. Indicator results according to reference points indicate no significant signals of reduction optimal length class (Lopt), small-size or large-size class. In 2016 and 2018 uncertain overexploitation of small-scale classes leads to no significant changes was underlined. In terms of biological and fisheries data lacking, LBI methods allow to perform stock assessment procedure more stable and robust then surplus or cohort approach, and output scientific advice to fisheries management.

Analytical reference points for age-structured models: application to data-poor fisheries

2009 ◽  
Vol 67 (1) ◽  
pp. 165-175 ◽  
Author(s):  
Elizabeth N. Brooks ◽  
Joseph E. Powers ◽  
Enric Cortés
Keyword(s):  
Stock Assessment ◽  
Meta Analysis ◽  
Reproductive Rate ◽  
Biological Data ◽  
Reference Points ◽  
Assessment Model ◽  
Shark Species ◽  
Stock Status ◽  
Age Structured ◽  
Analytical Reference

AbstractBrooks, E. N., Powers, J. E., and Cortés, E. 2010. Analytical reference points for age-structured models: application to data-poor fisheries. – ICES Journal of Marine Science, 67: 165–175. Analytical solutions for biological reference points are derived in terms of maximum lifetime reproductive rate. This rate can be calculated directly from biological parameters of maturity, fecundity, and natural mortality or a distribution for this rate can be derived from appropriate metadata. Minimal data needs and assumptions for determining stock status are discussed. The derivations lead to a re-parameterization of the common stock–recruit relationships, Beverton–Holt and Ricker, in terms of spawning potential ratio. Often, parameters in stock–recruit relationships are restricted by tight prior distributions or are fixed based on a hypothesized level of stock resilience. Fixing those parameters is equivalent to specifying the biological reference points. An ability to directly calculate reference points from biological data, or a meta-analysis, without need of a full assessment model or fisheries data, makes the method an attractive option for data-poor fisheries. The derivations reveal an explicit link between the biological characteristics of a species and appropriate management. Predicted stock status for a suite of shark species was compared with recent stock assessment results, and the method successfully identified whether each stock was overfished.

scholarly journals Evaluation of the robustness of maximum sustainable yield based management strategies to variations in carrying capacity or migration pattern of Atlantic bluefin tuna (Thunnus thynnus)

2007 ◽  
Vol 64 (5) ◽  
pp. 837-847 ◽  
Author(s):  
Laurence T Kell ◽  
Jean-Marc Fromentin
Keyword(s):  
Carrying Capacity ◽  
Management Strategy ◽  
Stock Assessment ◽  
Management Strategies ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Sustainable Yield ◽  
Size Limit ◽  
Atlantic Bluefin Tuna ◽  
Spawning Stock

In this study, we examine the performances of current stock assessment methods with respect to their ability to (i) provide estimates of maximum sustainable yield (MSY), FMSY, and BMSY and (ii) assess stock status and exploitation level relative to MSY targets. The robustness of the current International Commission for the Conservation of Atlantic Tunas (ICCAT) management strategy is then evaluated with respect to uncertainty about the true population dynamics and contrasted with a simpler management strategy based solely on a size limit. Reference points are more robust to dynamic uncertainty than the estimates of absolute values and trends in F and spawning stock biomass. However, their performances depend on the underlying dynamics (they perform better when fluctuations come from changes in the carrying capacity than migration) and on when they are implemented relative to the intrinsic cycle of the population. Reference points based on F were less biased and more precise than those based on biomass and (or) yield. Although F0.1 appeared to be the best proxy for FMSY, it cannot indicate past and current levels of exploitation relative to FMSY when there is uncertainty about the dynamics. Finally, the F0.1 management strategy of ICCAT performed only slightly better than a simpler strategy based on size limit and led to lower catch levels.

Spawning biomass reference points for exploited marine fishes, incorporating taxonomic and body size information

2012 ◽  
Vol 69 (9) ◽  
pp. 1556-1568 ◽  
Author(s):  
James T. Thorson ◽  
Jason M. Cope ◽  
Trevor A. Branch ◽  
Olaf P. Jensen
Keyword(s):  
Stock Assessment ◽  
Random Effect ◽  
State Space Model ◽  
Maximum Sustainable Yield ◽  
Marine Fishes ◽  
Reference Points ◽  
Data Set ◽  
Sustainable Fishery ◽  
Spawning Biomass ◽  
Taxonomic Order

Surplus production represents the processes that affect sustainable fishery harvest and is central to the ecology and management of marine fishes. Taxonomy and life history influence the ratio of spawning biomass at maximum sustainable yield to average unfished spawning biomass (SBMSY/SB0), and estimating this ratio for individual stocks is notoriously difficult. We use a database of published landings data and stock assessment biomass estimates and determine that process errors predominate in this data set by fitting a state–space model to data from each stock individually. We then fit multispecies process-error models while treating SBMSY/SB0as a random effect that varies by taxonomic order and maximum length. The estimated SBMSY/SB0 = 0.40 for all 147 stocks is intermediate between the values assumed by the Fox and the Schaefer models, although Clupeiformes and Perciformes have lower and Gadiformes and Scorpaeniformes have higher SBMSY/SB0values. Model selection supports the hypothesis that large-bodied fishes for a given taxonomic order have relatively higher SBMSY/SB0. Results can be used to define reference points for data-poor fisheries or as input in emerging assessment methods.

Comparing performance of catch-based and length-based stock assessment methods in data-limited fisheries

2020 ◽  
Vol 77 (6) ◽  
pp. 1026-1037 ◽  
Author(s):  
Maite Pons ◽  
Jason M. Cope ◽  
Laurence T. Kell
Keyword(s):  
Closed Loop ◽  
Stock Assessment ◽  
Maximum Sustainable Yield ◽  
Assessment Methods ◽  
Small Scale ◽  
Small Scale Fisheries ◽  
Management Procedures ◽  
Spawning Potential Ratio ◽  
The Common ◽  
The One

The quantity of data from many small-scale fisheries is insufficient to allow for the application of conventional assessment methods. Even though in many countries they are moving to closed-loop simulations to assess the performance of different management procedures in data-limited situations, managers in most developing countries are still demanding information on stock status. In this study we use the common metric of harvest rate to evaluate and compare the performance of the following catch-only and length-only assessment models: catch – maximum sustainable yield (Catch-MSY), depletion-based stock reduction analysis (DBSRA), simple Stock Synthesis (SSS), an extension of Catch-MSY (CMSY), length-based spawning potential ratio (LBSPR), length-based integrated mixed effects (LIME), and length-based Bayesian (LBB). In general, results were more biased for slightly depleted than for highly depleted stocks and for long-lived than for short-lived species. Length-based models, such as LIME, performed as well as catch-based methods in many scenarios, and among the catch-based models, the one with the best performance was SSS followed by CMSY.

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.

scholarly journals Can fisheries-induced evolution shift reference points for fisheries management?

2013 ◽  
Vol 70 (4) ◽  
pp. 707-721 ◽  
Author(s):  
Mikko Heino ◽  
Loїc Baulier ◽  
David S. Boukal ◽  
Bruno Ernande ◽  
Fiona D. Johnston ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Fish Population ◽  
Reference Points ◽  
Population Characteristics ◽  
Biological Processes ◽  
Fishing Mortality ◽  
Intended Meaning ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Induced Changes

Abstract Heino, M., Baulier, L., Boukal, D. S., Ernande, B., Johnston, F. D., Mollet, F. M., Pardoe, H., Therkildsen, N. O., Uusi-Heikkilä, S., Vainikka, A., Arlinghaus, R., Dankel, D. J., Dunlop, E. S., Eikeset, A. M., Enberg, K., Engelhard G. H., Jørgensen, C., Laugen, A. T., Matsumura, S., Nusslé, S., Urbach, D., Whitlock, R., Rijnsdorp, A. D., and Dieckmann, U. 2013. Can fisheries-induced evolution shift reference points for fisheries management? – ICES Journal of Marine Science, 70: 707–721. Biological reference points are important tools for fisheries management. Reference points are not static, but may change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to “shifting” reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in “true” reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in more perilous directions, such that actual risks are greater than anticipated. Our qualitative analysis suggests that all commonly used reference points are susceptible to shifting through fisheries-induced evolution, including the limit and “precautionary” reference points for spawning-stock biomass, Blim and Bpa, and the target reference point for fishing mortality, F0.1. Our findings call for increased awareness of fisheries-induced changes and highlight the value of always basing reference points on adequately updated information, to capture all changes in the biological processes that drive fish population dynamics.

An age-structured model with leading management parameters, incorporating age-specific selectivity and maturity

2008 ◽  
Vol 65 (2) ◽  
pp. 286-296 ◽  
Author(s):  
Robyn E Forrest ◽  
Steven J.D. Martell ◽  
Michael C Melnychuk ◽  
Carl J Walters
Keyword(s):  
Life History Traits ◽  
Stock Assessment ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Fish Stock ◽  
Structured Model ◽  
Specific Selectivity ◽  
Stock Recruitment ◽  
Age Structured ◽  
Age Structured Model

Previous authors have shown analytically that the optimal equilibrium harvest rate (UMSY) for an iteroparous fish stock is a function of the slope of the stock-recruitment curve at low stock size (α) and that UMSY can therefore be considered a direct measure of stock productivity. As such, it can be used as a leading parameter in stock assessment models and directly estimated using Bayesian or similar techniques. Here we present an alternative method for deriving α from UMSY that incorporates age-specific selectivity and fecundity, avoiding assumptions of knife-edged recruitment and maturity. We present an age-structured model with two fisheries reference points (UMSY and maximum sustainable yield, MSY) as its leading parameters. We show equilibrium properties of the model, chiefly in terms of its ability to show relationships between life history traits, density dependence, and UMSY. We also demonstrate a simple Bayesian estimation routine to illustrate estimation of UMSY and MSY directly from data. We compare our results to those from a structurally identical model with leading biological parameters. Using models with leading management parameters can improve communicability of results to managers.

scholarly journals Exploitation status and stock assessment of the smooth clam Callista chione (Linnaeus, 1758) in the northern Alboran Sea (GSA01-W Mediterranean Sea)

2018 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
JORGE BARO ◽  
TERESA GARCIA ◽  
JAVIER URRA ◽  
MATIAS LOZANO ◽  
JOSE LUIS RUEDA
Keyword(s):  
Stock Assessment ◽  
Economic Value ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Production Model ◽  
Total Biomass ◽  
Alboran Sea ◽  
Callista Chione ◽  
Exploitation Status ◽  
Alborán Sea

The smooth clam, Callista chione (Linnaeus, 1758), is a venerid bivalve widely appreciated in southern Spain where it represents the top commercial bivalve species in terms of landings and economic value. In this area, a total of 223 artisanal boats (68% of the artisanal fleet) are involved in shellfishing targeting bivalve molluscs, including the smooth clam. The artisanal mechanised dredging that targets C. chione in the northern Alboran Sea is described and the current exploitation status of its populations is analysed. A surplus-production model was run using ASPIC and used to assess the temporal variation in the levels of fishing for this bivalve throughout the study period (2002-2015), as well as to suggest conservation reference points that could guarantee the sustainable exploitation of this resource. During the study period, the maximum C. chione catch was registered in 2003 (306 t) and the minimum in 2006 (93 t). The ASPIC model for C. chione stock suggests that a Maximum Sustainable Yield (MSY) of 216 t could be produced from a total stock biomass of 983 t (Bmsy) at a fishing mortality rate of total biomass of 0.22 (Fmsy), with B/Bmsy and F/Fmsy values of 1.34 and 0.82, respectively, indicating that the stock is approaching good status.

scholarly journals A continuous hockey stick stock–recruit model for estimating MSY reference points

2010 ◽  
Vol 67 (8) ◽  
pp. 1780-1784 ◽  
Author(s):  
Benoit Mesnil ◽  
Marie-Joëlle Rochet
Keyword(s):  
Stock Assessment ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Sustainable Yield ◽  
Political Commitment ◽  
Hockey Stick ◽  
Differentiable Functions ◽  
Piecewise Function ◽  
Management Plans ◽  
Stock Recruitment

Abstract Mesnil, B., and Rochet, M-J. 2010. A continuous hockey stick stock–recruit model for estimating MSY reference points. – ICES Journal of Marine Science, 67: 1780–1784. With political commitment to restore stocks to levels where they can produce maximum sustainable yield (MSY), fisheries managers request evaluation of management plans that include options for an FMSY policy. The procedure to estimate FMSY with dynamic-pool, stock assessment models is well established for common stock–recruitment relationships (S–RR), and this capacity is extended to another S–RR, a piecewise function known as the hockey stick (HS), which is frequently assumed when the data do not support more elaborate functions. However, the HS is not continuous, which makes it problematic for this application, where differentiable functions are required. The bent-hyperbola model proves to be an adequate continuous equivalent to the HS for estimating FMSY.

scholarly journals Stock Assessment: Sustainable management in high and medium Araguari River, Amapá, Brazil.

2020 ◽  
Vol 42 ◽  
pp. e71
Author(s):  
Luiza Prestes ◽  
Fabiana Calacina da Cunha ◽  
Maria Gercilia Mota Soares ◽  
Marcos Sidney Brito Oliveira ◽  
Netie Izabel Oliveira ◽  
...  
Keyword(s):  
Natural Resources ◽  
Sustainable Management ◽  
Stock Assessment ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Sustainable Yield ◽  
Maximum Economic Yield ◽  
The Status ◽  
Future Management

Fisheries in Araguari river is an alternative income for families that depend on exploitation of natural resources. This study evaluates fisheries production in high and medium Araguari river to determine the bioeconomic reference points of fishery activities. Logbooks of fisheries were used from Fishermen Colony Z-16 from 2003 to 2010. The Maximum Sustainable Yield (MSY) and Effort at Maximum Sustainable Yield (fmsy) was: MSYSchaefer = 11246 kg and fmsy = 754 fisheries/year, and MSYFox = 11478 kg and fmsy = 1214 fisheries/year and at Bioeconomic Equilibrium (Eebe) Eebe = 10712 kg and Effort at Bioeconomic Equilibrium (febe) febe = 918 fisheries/year. The status of fisheries from Araguari River was declared as overfishing and in this study, we found the same results. The Maximum Economic Yield (MEY) was reached too, as the fisheries were at Bioeconomic Equilibrium (EBE). The fishery mortality (Fyear/Fmsy) and fishery effort (fyear/fmsy) trends show that from 2003 to 2009 the values were sustainable. In 2010 those trends became unsustainable, and the Maximum Economic Yield (MEY) for all years is unsustainable too. It is required this study be considered in future management agreements.

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