Estimates Of Maximum Sustainable Yield Research Articles

Estimating the growth parameters, exploitation rate, biomass and maximum sustainable yield of long whisker catfish Mystus gulio (Hamilton, 1822) in the coastal waters from southwestern Bangladesh

The research provides a comprehensive analysis of Mystus gulio including growth pattern, growth parameters, recruitment patterns, mortality rates, biomass, exploitation rate (E), and the estimation of maximum sustainable yield (MSY) within the southwestern coastal waters of Bangladesh. From January to December 2017, fishers provided around 1200 specimens. FAO-ICLARM Stock Assessment Tool and Excel-add-in-solver were used to assess stock status through length-frequency data. Indeed, the research findings indicated that the population of M. gulio displayed negative allometric for both individuals (b = 2.53 for male, b = 2.50 for female), as demonstrated by the calculated allometric coefficient value. Nonetheless, the population's dynamic characteristics revealed an asymptotic length (L∞) of 19.34 cm, 23.28 cm and growth coefficient (K) 0.94 year−1 and 0.81 year−1 for male and female M. gulio. The growth performance indexes (Ø') of 2.55 and 2.64 for male and female and maximum lifespan (tmax) 3.20 years and 3.70 years respectively. This study revealed that the slightly variations in the natural mortality rate (M) for both specimens at 1.55 year−1 and 1.59 year−1. The fishing mortality rate (F) 2.75 year−1 and 1.98 year−1and total mortality rate (Z) 4.30 year−1 and 3.57 year−1 for male and females, respectively. The maximum permissible exploitation rate (Emax = 0.421) was lower than the actual exploitation rate (E = 0.63). The MSY was calculated at 67.968 metric tons. Without a doubt, overfishing stands out as the most critical threat to the wild stock. Therefore, it is clear that the existing fishing approach was not efficiently managed the standing stock in a sustainable manner. The findings would be useful for established proper fishing regulations in coastal waters and the surrounding ecosystems.

Study of the coastal reef fishery pressure in a South Pacific Island (Bora-Bora, French Polynesia)

In the context of the general overexploitation of South Pacific reef fisheries, there is a global push to precisely define fishery parameters such as fishing effort, annual landings, and exploitation levels. In Bora-Bora, several surveys were performed to define the fishing grounds and the fishing effort of the reef fishery for the first time. Maps of the fishing grounds under different fishing pressures were created for the Bora-Bora reef fishery. The average fishing effort throughout the lagoon was 40 trips week−1 km−2. Annual landings were estimated following two different methods: school participatory surveys and landing based on the catch per unit effort. These estimations were used to determine that the maximum sustainable yield of the island's fisheries was 6.5 tons km−2 year−1. the reported annual yield in 2022 was 5.35 tons km−2 year−1, under the estimated maximum sustainable yield. The level of exploitation of the fisheries was also estimated based on the catch size composition of the ten most fished species. This revealed that fishing is responsible for more than 50% of fish mortality in six of the ten studied species, and that catch length could be increased to optimize both catches and biomass. Overall, the Bora-Bora reef fishery may be experiencing growth overfishing (i.e., the catching of fish that are too small to maximise biological sustainability and economical yield), which can endanger stock recruitment in the future if no actions are taken.

Assessment of Three Major Shrimp Stocks in Bangladesh Marine Waters Using Both Length-Based and Catch-Based Approaches

Penaeus monodon (tiger shrimp), Metapenaeus monoceros (brown shrimp), and Fenneropenaeus indicus (white shrimp) are the most economically important shrimp species in the waters of the Bay of Bengal, Bangladesh. This is the first analytical study to assess three major shrimp stocks using both length-based and catch-based methods, such as length-based Bayesian biomass estimation (LBB), length-based indicator (LBI), and a catch-based method entitled JABBA (Just Another Bayesian Biomass Assessment), to explore and process the data; estimate the growth parameters, with length at first capture; present relative biomasses; and approximate the reference points. The parameters of the von Bertalanffy Growth Function (VBGF) analysis for the tiger, brown, and white shrimps were L∞ = 113.0 mm, 85.4 mm, and 76.4 mm, respectively, for carapace length. Our results showed that the relative biomass level (B/BMSY) of the tiger shrimp was 0.43, suggesting an overfished status, and brown and white shrimps were 0.84 and 0.96, indicating that they were fully exploited but not overfished. This study, therefore, advised an optimum carapace length limit to catch from 57.0–70.0 mm for tiger shrimp, 44.0–53.0 mm for brown shrimp, and 40.0–48.0 mm for white shrimp. The estimated maximum sustainable yield (MSY) reference points were as follows: optimal biomass BMSY = 3116 mt, 15,885 mt, and 2649 mt for tiger, brown, and white shrimp, respectively, and optimal harvest rate uMSY = 12%, 33%, and 8% for tiger, brown, and white shrimp, respectively. The average annual catch values for the last ten years were 265 mt, 2396 mt, and 115 mt below the estimated MSY values of 389 mt, 4899 mt, and 209 mt for tiger, brown, and white shrimp, respectively. But, brown shrimp had the estimated highest carrying capacity (31,770 mt) and intrinsic growth rate (0.66) than the tiger and white shrimp, which was replicated distinctly in the graphical representation of the Kobe plot and the surplus production plot. Hence, the brown shrimp stock is estimated to be in a better state than the tiger and white shrimp stocks.

Fishery and population characteristics of the Indian white shrimp, Penaeus indicus H. Milne Edwards, 1837 (Decapoda, Dendrobranchiata) in Pulicat Lake, southeast coast of India

Abstract Fishery and population characteristics of the Indian white shrimp, Penaeus indicus, were studied in Pulicat Lake, on the southeast coast of India, using the FiSAT software package. The asymptotic length (), growth coefficient (K) and arbitrary origin of growth (t0) were estimated by the ELEFAN method to be 16.18 cm, 0.60 year−1 and −0.18 year, respectively. The asymptotic length () was calculated as 16.09 cm using the Wetherall method. The growth performance index (Ø′) was found to be 2.19. The mortality parameters Z, F and M were computed to be 3.85, 2.30 and 1.55 year−1, respectively. The pattern of recruitment was observed to be year-round, with a peak from June to September. The total stock, annual catch and exploitation rate for P. indicus were estimated to be 1518.43 tonnes, 809.3 tonnes, and 0.59 year−1, respectively. The estimated Maximum Sustainable Yield (MSY) was found to be 131.95 tonnes less than the annual catch. The stock of P. indicus was found to be over-exploited, so it is suggested that the effort level be reduced by 16.3% in order to sustain this resource in Pulicat Lake.

Clupeids in the kaptai reservoir, a blessing or a curse: estimation of fisheries reference points

Sustainable fisheries management depends on the degree of the present exploitation status of significant fish stocks. A recently developed fish stock assessment approach, CMSY, was used to estimate the fisheries reference points of data-limited Gudusia chapra and Corica soborna from the Kaptai reservoir using catch data, resilience, and exploitation records during the first and last year of the time series catch data. CMSY, along with a Bayesian state-space Schaefer production model (BSM), estimated maximum sustainable yield (MSY) as 2680 mt and 2810 mt, and 3280 mt and 3020 mt for the above stocks, respectively. The MSY range for both stocks was higher than the last catches meaning that both stocks are perfectly sustainable. The lower biomass B (4340 mt) for G. chapra estimated by CMSY and BMSY (4490 mt) indicates that the stock has started to be depleted. However, considering the precautionary fisheries management, the lower limit of MSY might be suggested to follow. Therefore, it could be suggested not to exceed the MSY limit (2680 mt) for the sustainability of G. chapra stock while it was 3020 mt for the C. soborna fishery. The intrinsic growth rate r was 0.862–1.19 yr−1 for G. chapra and 0.428–0.566 yr−1 for C. soborna, suggesting a high and medium increase of biomass in the existing population, respectively. A F/FMSY less than 1 and B/BMSY greater than 1 report both stocks at underfishing and underfished states. The study recommends enforcing strict and lawful actions regarding the net's mesh size to catch less small fish. Otherwise, negligence of this crucial management practice may bring severe threats to the sustainability of the whole reservoir resources and the reservoir ecosystem.

Estimation of Maximum Sustainable Yield for Lesser Sciaenids Fishery of North-Eastern Arabian Sea using Surplus Production Model with Environmental Effects

Estimation of Maximum Sustainable Yield for Lesser Sciaenids Fishery of North-Eastern Arabian Sea using Surplus Production Model with Environmental Effects

Biomass dynamic model for multiple data series: An improved approach for the management of the red grouper (Epinephelus morio) fishery of the Campeche Bank, Mexico

This study analyzed the current status of the population and stock assessment of the red grouper Epinephelus morio from the Campeche Bank, Yucatán, based on the Schaefer biomass dynamic model and considering the three fleets that operate in the study area. Thus, five indices of relative abundance were used, expressed as catch per unit effort (CPUE). The carrying capacity (K) of the red grouper population was 293,851 t, with an intrinsic growth rate (r) of 0.232. The study indicated that the greatest contribution to the adjustment of the model was due to the CPUE of the industrial Mexican fleet. The catchability values showed differences between the fractions of red grouper caught using trips and hooks. Estimates of maximum sustainable yield (MSY= 17,031 t) and biomass at MSY (BMSY= 146,929 t) indicated that the current catch and the biomass are below their reference points, denoting a marine resource that has been overharvested. Historical analysis of the biomass and harvest ratio for the red grouper estimated from the Kobe diagram showed that the red grouper fishery has transitioned from overfished-overharvested from 1984 to 2014 to overfished-underharvested in 2015. Because the E. morio stock is particularly low in abundance, catches must be drastically reduced to allow the stock to recover more quickly. Only low quotas (3,200–4,000 t) or an annual harvest rate of 6% will reach the BMSY in the long term, recognizing that, for both management strategies, the MSY will not be reached for at least 15 years.

Reproductive potential and stock status of the anadromous shad, Tenualosa ilisha (Hamilton, 1822): Implications for managing its declining fisheries in northern Bay of Bengal bordering India

The anadromous shad, Tenualosa ilisha is a fish of high economic importance in countries flanking the Bay of Bengal (BoB). Its fishery in the northern BoB bordering India and the associated Bhagirathi–Hooghly river system has been declining. Scientific explanations on the existing fishery management recommendations, especially the length at first maturity (Lm50), minimum legal size (MLS), minimum mesh size for fishing nets and stock status were limited, raising serious concerns on the sustainability of its fisheries. Through the examination of its reproductive cycle, using histological maturity identifiers, the Lm50 of males and females were redefined at 265 mm TL/ 1.0 year age and 305 mm TL/ 1.2 year age, respectively. The size-based fecundity, sex ratio and abundance revealed that females of 281–360 mm TL/ 1.0–1.6 year of age have maximum reproductive potential. In the catch, 45%–65% of males and females were below Lm50. The temporal progression of mean length in the catch (MLC) and female length at maturity showed declining trend. Application of length-based indicators (LBI) and stock assessment models showed the fishery in near full exploitation, less optimal and undergoing multi-generation, indiscriminate, size-selective overfishing. The spawning stock biomass (SSB) has declined to 26.8% of the virgin SSB, while the yearly spawning potential ratio (SPR) ranged from 0.04 to 0.29, which is lower than the SPR threshold (0.3) suggested for sustaining a fishery. The species is both growth and recruitment overfished. Though the mean annual catch is marginally lower than the estimated maximum sustainable yield (MSY) of 32,953 t, any increase in fishing effort would further impact the SSB. Based on the results, a MLS of 360 mm TL, minimum mesh size of 110 mm for fishing gear and a precautionary annual catch limit of 30,000 t suggested for management, and the potential impact of implementing these on fishers’ catches discussed.

Status of the fishery of Jaffna lagoon, Sri Lanka

Jaffna lagoon (9° 50' N and 79° 50' E to 9°20' N and 80° 30' E) is the largest lagoon in Sri Lanka and it provides many services including fishing opportunities to the people in northern Sri Lanka. However, the status of the Jaffna lagoon fishery is not fully known at present due to the lack of detailed studies over the last 40 years. Therefore, this study was designed to fulfil this research gap. Both primary data and secondary data were used in this study. Primary data, including catch and fishing effort were collected at three major landing sites, Gurunagar, Paasaiyoor, and Kachchai by making fortnight field visits from March to December 2019. Secondary data of the monthly total catch and fishing effort were obtained from the district fisheries offices in Jaffna and Kilinochchi districts in order to estimate MSY and FMSY. This study revealed that ~5340 fishers confined to 39 landing sites were actively engaged in lagoon fishing during the study period using 12 different fishing methods. Fyke nets (71%) followed by stake nets (10%), lagoon seines, and lagoon boat seines (6%) are the widely used fishing methods in lagoon fisheries. Catch rates of major fishing gear were calculated and recorded as kg fisherman-1, day-1. Stake net (37kg ± 7) reported a significantly higher catch rate than fyke net (18kg ± 3), seine net (17kg ± 6), and crab net (16kg ± 3) (p<0.05; ANOVA). Both mechanized (59%) and non-mechanized (41%) crafts are used in the lagoon fishing practices. Forty-six commercially important finfish and shellfish species belonging to 25 families were identified in the lagoon catches of which Penaeidae made the highest percentage contribution (27%), followed by Siganidae (13%), Mugilidae (11%), Lethrinidae (10%), and Gerreidae (9%). Analysis of secondary data confirmed the increasing trend of fishing effort since 2009 but the total landings declined gradually after reporting its maximum value of 6958 Mt. in 2012. A rough estimate of maximum sustainable yield of the fishery of Jaffna lagoon was 6,694 Mt with the annual fishing effort (FMSY) of 1007 crafts. As the current fishing effort is higher than the FMSY, input control measures are recommended to utilize the lagoon fishery resources in a sustainable manner.

Evaluating the potential for an increased and sustainable commercial fisheries production across multiple jurisdictions and diverse fisheries

We describe a first estimate of the potential to increase production from Australia’s commercial fisheries based on the difference between current catches and maximum sustainable yield (MSY). MSY is not being advocated as a target reference point but enables a level of consistency across species and/or jurisdictions with different reference points. MSY estimates were obtained for 290 species/stocks that comprised 84% of annual landings. 75% of the estimates were computed using methods applied specifically for this study, aided by an assessment framework, and supporting software. The catch-MSY method was used extensively given the lack of formal assessments for many species, and the limitations of taking this approach are discussed. The results indicated that potential production could be more than double the current national catch (an increase over current catches of about 124%), but potential increases varied considerably among Federal, State and Territory jurisdictions. The potential for increased production was particularly influenced by predictions for highly productive small pelagic fishes, although ignoring the potential for increased catches of these species still led to an estimate of an increase of almost 80% over current catches. Other factors such as whether an increase in production has market demand are also clearly important, along with other social and economic issues. Impacts on ecosystem sustainability and the consequences of climate change were beyond the scope of this study and would need to be considered in separate analyses. However, in making our estimates of potential production we acknowledged the issues with attempting to use single species approaches to provide fish community wide estimates and acted conservatively with our interpretation. Consequently, the results presented in this paper provide useful insights into possible biologically sustainable catches and the potential for increased production.

Accounting for non-stationary stock–recruitment relationships in the development of MSY-based reference points

Asbtract Stock–recruitment relationships (SRRs) may vary over time due to ecological and anthropogenic impacts, challenging traditional approaches of calculating maximum sustainable yield (MSY)-based reference points that assume constant population traits. We compare seven methods to calculate MSY, FMSY and BMSY by modelling constant, stochastic (uncorrelated), and autocorrelated SRRs using simulations and two case studies [Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) on the Grand Bank off Newfoundland, Canada]. Results indicated that the method used to model SRRs strongly affected the temporal pattern of recruitment projection, and the variations generated by autocorrelated SRRs were more similar to observed patterns. When the population productivity had low-frequency and large-magnitude variations, stochastic SRRs generated greater MSY and FMSY estimates than constant or autocorrelated SRRs, while no consistent pattern of BMSY was detected. In the case studies, stochastic and autocorrelated SRRs produced asymmetric relationships between fishing mortality and yield, with higher risk of overfishing by going beyond FMSY. Overall, our results suggest that caution should be taken when calculating MSY-based reference points in highly dynamic ecosystems, and correctly accounting for non-stationary population dynamics could, therefore, lead to more sustainable fisheries.

Maximum Sustainable Yield Estimates of Marine Captured Shrimp Fishery of the Bay of Bengal, Bangladesh by Using Surplus Production Model

Surplus-production models (SPMs) are the foremost conventional methodical tool for assessing fish stock when the data comprised of a time series of catches for an exploited population. Annual catch and effort data of 24 years from 1991 to 2014 were analyzed to estimate the Maximum Sustainable Yield (MSY) of marine captured shrimps of Bangladesh by using packages of CEDA and ASPIC. The maximum catch was found 4188 Mt in 1992 and the minimum was 2175 Mt in 2006. In CEDA, the MSY was estimated by using the initial proportion (IP) value of 0.7 because the starting catch was approximately 70% of the maximum catch. The estimated MSY values of Fox and Schaefer from CEDA with two error assumptions were 2527 Mt and 2584 Mt; 2794 Mt and 2655 Mt, respectively. Besides, the estimated MSY results of Fox and Logistic (Schaefer) models from the ASPIC packages were 2472 Mt and 2347 Mt respectively. In conclusion, the estimated MSY values were smaller than the last catch (2733Mt) reveals the overfished stock of marine captured shrimp fishery which needed instant management strategies for sustainability.

Some consequences of unreported fishing on the results of simple fish stock assessment

Unreported fishing received less attention than illegal fishing but the later contributed the problem of data availability. Among various data needed for fish stock assessment, catch and fishing effort are popular for some preliminary analysis to describe annual trends of catch, fishing effort and catch per unit effort. Surplus production models can be used to determine the status of fish stock, maximum sustainable yield (MSY) and optimum annual fishing effort. Fisheries authorities then can determine some management measure promoting sustainability of the fisheries, such as total allowable catch. This study exercised some consequences of unreported fishing effort and catch data on the outputs of the assessment by a simulation with different levels of data using the model. The estimates of both MSY and optimum fishing effort were lower when catch and fishing effort were not fully reported. When the authority should firmly use the best available but limited data, their decision on the maximum annual catch and fishing effort will be more conservative. In contrast, their decision can be risky if over-estimated catch and fishing effort were used. If fishers expected fair levels of catch and fishing effort, the authorities can firmly ask them to provide data completely.

Stock assessment of Prochilodus nigricans (Actinopterygii: Characiformes: Prochilodontidae) using two distinct algorithms, in the context of a small-scale Amazonian fishery

Background. Despite the importance of inland fishery, assessments of exploited inland stocks have relied on data-deficient databases, mainly in developing countries. In this paper, we employed two distinct analytical methods to evaluate the stock status of Prochilodus nigricans Spix et Agassiz, 1829, the most important fish in the Amazonian freshwater landings. In this study, we intended to test the sustainability of small-scale fisheries comparing two different methods. Materials and methods. The population dynamic of P. nigricans was studied using length and weight data for fish caught in Manacapuru Lake and the lower stretch of the Solimões River. Estimates of maximum sustainable yield and corresponding fishing mortality for 2012 and 2013, using Beverton–Holt curve, indicated an overfishing status for both years. At the same region, fishers were interviewed and their knowledge on the P. nigricans stock status was assessed using a stock assessment methodology based on fishers’ knowledge, known as ParFish. Results. Both yield per recruit curves employed to assess the stock status of P. nigricans in 2012 and 2013 and ParFish approach indicate an overfishing status, but ParFish also found a high uncertainty level around 47%. Conclusion. The use of ParFish algorithm and traditional knowledge can provide qualitatively similar results to conventional models, such as the Beverton–Holt approach. The ParFish approach shows the advantage including confidence intervals to its estimates.

Estimation of Maximum Sustainable Yield (MSY) for Sustainable Fish Catch

Fishery is an entity engage with fish catch on the sea ground by fisherman. The fish catch in Peninsular Malaysia has declined by more than 90% since 1960s. Thus, it is important to know the maximum sustainable yield in order to overcome the decreasing number of fish and estimate the number of fishes that can be caught from the sea without endangering the fish population. The main purpose of this study is to calculate the maximum sustainable yield of fish catch in Terengganu by applying Bayesian surplus method. The results show that the amount of maximum sustainable yield is 100100 tons with 205700 fishing trips per year. Based on the value of maximum sustainable yield and optimum number of fishing trip, the current fish stocks have been overfished from year 2000 to 2008 since the fish catch and fishing effort for the year exceeded the optimum value. As a result, the numbers of fish catch for the year 2009 to 2016 was lower even though the fisherman put higher fishing effort.

Potential, production and utilization level of pelagic fish resource in Ambon City

In responsible and sustainable fisheries, marine resources should be exploited at optimum level in which potency, production and utilization level is known. This research was conducted to analysed potency, production and utilization level of pelagic fish in Ambon Island waters. Data for the analysis was obtained from the secondary data of Dinas Kelautan dan Perikanan Maluku province in the form of catch and effort for period 2005–2015 and then analysed by using Schaefer model. Estimated Maximum Sustainable Yield (MSY) was 103,513 tons with Total Allowable Catch (TAC) was 82,811 tons. Production of pelagic fish fluctuated but tended to increase due to increasing of fishing vessels and fishing gears. Catch per unit effort of purse seine and pole and line contributed more for the pelagic fish production than five other fishing gears. The utilization of pelagic fish resources in Ambon tended to increase with annual average 61.7% from TAC or 49.40% of MSY during the period of 2005-2015. In the last three years (2013-2015) the level of utilization increased significantly and has reached 98.31% from TAC or 78.65% of MSY which leads to fully exploitation. These results indicated that fishing effort should be maintained and monitored strictly to prevent over exploitation of pelagic fish resource.

Improved approximations for estimation of size-transition probabilities within size-structured models

Modelling annual growth of individuals in a size-structured model requires calculation of the size-transition probabilities for moving from one size class to another. This requires evaluation of two-dimensional integrals when there is individual variability in growth. For computational simplicity, it is common to approximate the integrals by setting all individuals in a size class to the midsize of that class or by ignoring the individual variability. We develop a more accurate approximation that assumes a uniform distribution in size within each size class. The approximation is fast and hence feasible for Bayesian models in which the matrix of transition probabilities must be computed for each posterior sample. The improved accuracy of the new approximation is shown to hold over a diverse range of formulations for incremental growth. For the New Zealand Paua 5A (Haliotis iris) stock assessment model, it was found to reduce the average approximation error of the size-transition probabilities by 86% and 98% compared with the midpoint and deterministic growth approximations, respectively. Moreover, the midpoint and deterministic approximations inflated the estimated maximum sustainable yield by 6% and 8%, respectively, and the current biomass by almost 30% in comparison with the more accurate approximation.

Population dynamics and yield of the black goby Gobius niger L. in Algeria (Gulf of Annaba)

Event Abstract Back to Event Population dynamics and yield of the black goby Gobius niger L. in Algeria (Gulf of Annaba) Abderrahmane Kassar1*, Alaeddine Benallia1, Daoud Bouchelif1 and Farid Hemida1 1 École Nationale Supérieure des Sciences de la Mer et de l'Aménagement du Littoral, Algeria The black goby Gobius niger L., 1758 is a demersal gobiid fish caught by bottom trawl in the Gulf of Annaba (South Western Mediterranean). No published prior studies on its biology, population dynamics or stock assessment has been conducted in Algeria. A monthly sampling of this species has been done between Dec 2015 and May 2016 from commercial catch in order to estimate the growth, mortality and exploitation parameters of the stock for the first time in the Algerian Basin. Maximum total length (TL) and maximum total weight (TW) were 15.3 cm and 43.2 g, respectively. Power function type relationship between length and weight was obtained using 344 couples and it was written as TW = 0.0095*TL^3.0701. Estimated von Bertalanffy growth parameters using ELEFAN I routine in FiSAT II program were as follows: L∞ = 16.03 cm and K = 0.8 year-1. The estimated value of Total Mortality based on length converted catch curve was Z = 1.93 year-1. Natural Mortality calculated using Djabali et al. method (1994) based on the asymptotic length and the growth curvature was M = 0.6 year-1. Computed Fishing Mortality was F = 1.33 year-1. The Thompson & Bell model (1934) was used for stock assessment based on data obtained from Jones analysis (1983). Model estimated Maximum Sustainable Yield was MSY = 9 tonnes that corresponds to a 2.6 F-factor. As the reference yield is 8.5 t, there would be scope only to marginally increase the catch by 5.56%. A doubled fishing effort would increase the catch by 7%. Exploitation rate is at its optimum and the applied model recommends maintaining the actual catch. It could also be reduced by a third (loss of 9% of yield), which is more careful in order to protect the stock and preserve the resource in a sustainable way. References Djabali, F., Mehailia, A, Koudil, M., Brahmi B. (1994). A reassessment of equations for predicting natural mortality in Mediterranean teleosts. Naga, the ICLARM Quarterly 17:1, 33-34. Jones, R. (1984). Assessing the effects of changes in exploitation pattern using length composition data (with notes on VPA and cohort analysis). FAO Fisheries Technical Paper 256. Rome: Food and Agriculture Organization of the United Nations. Thompson, W. F., & Bell, F. H. (1934). Effect of changes in intensity upon total yield and yield per unit of gear. Report of the International Fisheries Commission 8, 7-49. Keywords: Algerian basin, Bottom trawling, Gobiidae, Mediterranean Sea, VBGM Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Oral Topic: ECOLOGY AND LIFE CYCLES Citation: Kassar A, Benallia A, Bouchelif D and Hemida F (2019). Population dynamics and yield of the black goby Gobius niger L. in Algeria (Gulf of Annaba). Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00140 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Jul 2019; Published Online: 14 Aug 2019. * Correspondence: Mr. Abderrahmane Kassar, École Nationale Supérieure des Sciences de la Mer et de l'Aménagement du Littoral, Algiers, Algeria, a.w.kassar@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Abderrahmane Kassar Alaeddine Benallia Daoud Bouchelif Farid Hemida Google Abderrahmane Kassar Alaeddine Benallia Daoud Bouchelif Farid Hemida Google Scholar Abderrahmane Kassar Alaeddine Benallia Daoud Bouchelif Farid Hemida PubMed Abderrahmane Kassar Alaeddine Benallia Daoud Bouchelif Farid Hemida Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Maximum Sustainable Yield Estimates of Carangoides Fishery Resource in Pakistan and its Bioeconomic Implications

Maximum Sustainable Yield Estimates of Carangoides Fishery Resource in Pakistan and its Bioeconomic Implications

Model simulations to determine optimal fishing effort and season duration for a tropical shrimp fishery

Kuwait’s shrimp fishery presents typical tropical shrimp fishery characteristics with highly variable recruitment, fast growth and strong seasonal patterns. Both the General Production Model and Age-structured Model were chosen to assess the stock status of the Kuwait’s shrimp fishery. The estimated Maximum Sustainable Yield (MSY) was 2 518 metric ton (t) with a corresponding fishing efforts ( fMSY ) 7 265 standard boat-days from the General Production Model. Similar results from the Age-structured Model were 1 936 t and 6 449 boat-days respectively. Comparing these results with the average annual shrimp landings (1 772 t) and average fishing effort (9 710 boat-days) in the past 10 years, we concluded that the fishery was overfished. Model simulations to show the changes of recruitment, biomass and possible catch under different fishing effort scenarios indicated possible stock collapse if the fishing effort continually increase. But both shrimp recruitment and biomass will increase if the current fishing effort is reduced. Model simulations also showed a possible increase of MSY by delaying the opening or by closing the season earlier. Based on these results, recommendations to improve the management of Kuwait’s shrimp fishery are presented.