Concept Of Maximum Sustainable Yield Research Articles

Application of Mathematical Model in Bioeconomic Analysis of Skipjack Fish in Pelabuhanratu, Sukabumi Regency, Jawa Barat

Presently, sustainability has emerged as a crucial and compelling concern across diverse sectors, evolving into a long-term agenda championed by the United Nations through the implementation of the Sustainable Development Goals (SDGs). Within the SDGs, particularly under point 14 addressing life below water, emphasis is placed on ensuring sustainability in aquatic ecosystems, encompassing the fisheries sector. The concept of Maximum Sustainable Yield (MSY) holds significance in the bioeconomic analysis of fisheries, influencing decision-making processes aimed at preserving sustainability. Regrettably, several studies have identified inaccuracies in the determination of MSY, leading to instances of overfishing in various regions. Conversely, it is imperative to give due attention to Maximum Economic Yield (MEY) to ensure that economic considerations remain integral to decision-making processes. Consequently, a more comprehensive and detailed bioeconomic analysis, incorporating mathematical models, becomes essential. Among these models, the logistic growth rate model and the Gompertz growth rate model stand out as significant contributors.

Maximum sustainable yield as a reference point in the presence of fishing effort that follows an ideal free distribution

AbstractThe concept of maximum sustainable yield (MSY), and the underlying Schaefer model, remain relevant in fisheries management today in spite of past difficulties. However, this model is often applied without the consideration of the spatial structure or dynamics of fishing activities. We expand the Schaefer model to account for multiple fishing sites and fishing activities (effort) that follow an ideal free distribution (IFD, a form of Nash equilibrium) driven by exploitation. We explore this conceptual model using both analytical and numerical solutions. MSY across the fishery is unaffected by the spatial structure when fishing is allocated independently within sites. However, in other cases IFD effort dynamics depress MSY and modify the values of associated reference points. The game theoretic aspect of fleet dynamics should be considered in the use of MSY as a management reference point or during the application of the Schaefer model to data‐limited fisheries.

Are maximum yields sustainable? Effect of intra-annual time-scales on MSY, stability and resilience

The concept of Maximum Sustainable Yield (MSY) have been lying at the core of the theory of sustainable harvesting a fishery for decades and have become a key reference point for many fishing administrations, including the European Union. However, the existence of a MSY relies on the stability of a population equilibrium. This hypothesis, though always true in the original Schaeffer model, is still challenging in more realistic and recent population models. However, recent advances shows that fish population can exhibit complex dynamics that are ill described by the classical theory. In particular, processes occurring at intra-annual time scales can affect the stability of a population equilibrium even in a strictly single species case. Associated to stability, the resilience of the equilibrium (defined as an inverse return-time following a perturbation) also matters in a management purpose. Here, we introduce an analytical single population model in discrete time with a monthly time-step allowing temporal distinction between maturation and recruitment with density-dependent mortality and fishing exploitation. We show that, thanks to an appropriate population structure, we can easily derive inter-annual population equilibrium, and study their resilience and stability properties. Then, we show that under classical hypothesis concerning density-dependence, equilibrium stability is not guaranteed and that MSY can, in theory, be associated to unstable or low resilient states. However such destabilisation seems unlikely with realistic sets of parameters. Finally, a numerical illustration for sole (Solea solea) of the Bay of Biscay suggests that the value of MSY was sensitive to maturation period whereas viability, stability and resilience was more sensitive to timing of recruitment. The value of FMSY appeared robust to uncertainty concerning maturation and recruitment. We conclude by saying that even if the risk of destabilisation is low for real populations, the risk of decreased resilience near the border of extinction should be cared of.

Reforming International Fisheries Law Can Increase Blue Carbon Sequestration

The oceans are by far the largest carbon sink and are estimated to have absorbed roughly 40 percent of anthropogenic carbon dioxide emissions since the beginning of the industrial era. The climate services performed by the oceans can be described as an interaction between a physical and a biological carbon pump. Whereas the role of the physical carbon pump is well established, the full scale of the climate services provided by the biological carbon pump has only recently been understood. This pump is made up of services provided by different marine species, from microbes to marine mammals. Many of these species are managed under the international law of the sea and subject to the concept of Maximum Sustainable Yield (MSY). Although the MSY concept has developed since its inception, maximum generation of fish for human consumption remains the core objective according to the law of the sea. Under MSY based management, states are not required to consider the climate services represented by different marine organisms, making this regime unable to balance the interest of maximizing fish as a product against the oceans’ role in carbon sequestration. In order to make optimal use of the carbon sequestering features of marine organisms, this perspective proposes five action points. Foremost, MSY should be complemented with a new management objective: maximum carbon sequestration (MCS). Although many aspects of climate-based fisheries management remain to be explored, it appears clear that this would imply allowing stocks to recover to maintain a larger amount of biomass, increasing conservation measures for species particularly efficient in providing negative emissions, differentiation of fisheries within species as well as a new approach to ecosystem management. Climate reforming international fisheries law could make an important contribution to the operationalization of the Paris Agreement on Climate Change, as well as the UN Sustainable Development Goals. As a first step, international guidelines should be developed on how to integrate the concept of maximum carbon sequestration in fisheries management.

Study of two species prey-predator model in imprecise environment with MSY policy under different harvesting scenario

Parameters involve in various ecological models are mostly uncertain due to ever changing characteristic of nature. This article, deals with a basic predator–prey model where ecological parameters are considered as parametric-functional nature of interval numbers. The dynamical behaviors of the model system have been discussed in the imprecise environment. Moreover, the concept of maximum sustainable yield (MSY) has been incorporated in the model system under imprecise environment, and MSY policies under different harvesting scenarios have been discussed. Finally all the analytical findings are testified through extensive numerical simulations and the article ended with a conclusion.

MSY needs no epitaph—but it was abused

AbstractThe maximum sustainable yield (MSY) concept is widely considered to be outdated and misleading. In response, fisheries scientists have developed models that often diverge radically from the first operational version of the concept. We show that the original MSY concept was deeply rooted in ecology and that going back to that version would be beneficial for fisheries, not least because the various substitutes have not served us well.

Maximum Sustainable Yield, Maximum Economic Yield and Sustainability in Fisheries

A brief review of the concept of Maximum Sustainable Yield (MSY) used in fisheries management is discussed. The convenience of assessing the exploited stocks with the aid of simulation is advised, because implies the possibility to analyze the age structure of the fishery in more detail, as compared to the traditional methods of fish stock assessment. Emphasis is given to the use of the MSY as limit reference point because as long as the Fishing Mortality or fishing effort required for that point is kept at lower values, the fishery will have a good chance to be sustainable. A mention of the Maximum Economic Yield is made, proposing its use a target for the management, because it is reached in general with lower F values that for the MSY, and this way keeping the fishery in a healthy condition.

Maximum sustainable yield, maximum economic yield and sustainability in fisheries

A brief review of the concept of Maximum Sustainable Yield (MSY) used in fisheries management is discussed. The convenience of assessing the exploited stocks with the aid of simulation is advised, because implies the possibility to analyze the age structure of the fishery in more detail, as compared to the traditional methods of fish stock assessment. Emphasis is given to the use of the MSY as limit reference point because as long as the Fishing Mortality or fishing effort required for that point is kept at lower values, the fishery will have a good chance to be sustainable. A mention of the Maximum Economic Yield is made, proposing its use a target for the management, because it is reached in general with lower F values then that for the MSY, and this way keeping the fishery in a healthy condition.

The performance and trade-offs of alternative harvest control rules to meet management goals for U.S. west coast flatfish stocks

U.S. federal fisheries managers are mandated to obtain optimum yield while preventing overfishing. However, optimum yield is not well defined and the concept of maximum sustainable yield (MSY) has often been applied to provide an upper bound for the optimum yield value, but determining the MSY, identifying the relative biomass that produces MSY and the associated fishing rate required (FMSY) is difficult. The Pacific Fishery Management Council, which manages groundfish stocks off the U.S. west coast, has employed proxy targets in lieu of species-specific estimates of MSY, BMSY, and FMSY. The proxy targets are life history specific, with flatfish stocks managed using a target BPROXY of 0.25 of unfished biomass and a harvest control rule that applies an exploitation rate equal to a spawner-per-recruit harvest rate of F0.30, with a linear reduction of catch to zero if the stock falls below 5% of unfished biomass (BLIMIT). A management strategy evaluation was performed to explore the performance of the current harvest control rule applied to flatfish stocks to meet management goals, along with alternative harvest control rules that explore varying the values for BPROXY,BLIMIT, and FSPR. Each of the harvest control rules explored maintained stocks at or near BPROXY when stock-recruit steepness was 0.85 or greater, with very low probabilities of reducing relative biomass below a minimum stock size threshold (set at 0.50 BPROXY of each harvest control rule). The most aggressive harvest control rule, which applied a BPROXY of 0.20 and a target harvest rate of F0.25, led to fishing rates that exceeded the operating model FMSY values for low steepness (0.75), reducing the stock below BPROXY with catches exceeding MSY. Trade-offs exist among alternative harvest control rules where the more aggressive harvest control rules resulted in higher average catches, but with an increase in the average annual variation in catches and a decrease probability of the relative biomass being with 10% of the BPROXY. The trade-offs among the performance metrics and alternative harvest control rules coupled with the risk to the resource across a range of life histories should be carefully considered by fishery managers when selecting a harvest control rule that will meet the goals of management.

Catch per unit effort, maximum sustainable yield and exploitation of demersal fish of Omani artisanal fishery

The artisanal fishery in Oman contributes over 90% of the total marine catch. The fish stocks in this fishery suffer from an increase of exploitation pressure due to open access system[1,2]. In that fishery, small fiberglass boats powered with engine dominate the fleets constituting about 99%[2]. The boats are less than 12 m length fishing with gears such as traps, bottom gill nets and hand lines. These boats obviously increased in the fishery during the last decade[3]. This is expected to have direct effect on the fish stocks and exploitation status. The production of artisanal fishery composed of some different categories of fish groups classified as large pelagic fish, small pelagic fish, demersal fish, sharks and rays, mollusks and crustaceans. Demersal fish category includes some important fish species which are selected for the present study. These fish include emperors (Lethrinus lentjan and Lethrinus nebulosus, family Lethrinidae), groupers (Epinephelus areolatus, Epinephelus chlorostigma and Epinephelus tauvina, family Serranidae), sea breams [Acanthopagrus bifasciatus (A. bifasciatus) and Argyrops filamentosus (A. filamentosus), family Sparidae], rabbit fish (Siganus canaliculatus, Siganus rivulatus, Siganus spinus and Siganus javus, family Siganidae), croakers [Atractoscion aequidens (A. aequidens), family Sciaenidae], sweet lips (Plectorhinchus pictus and Plectorhinchus schotaf, family Haemulidae), snappers (Lutjanus ehrenbergii and Lutjanus malabaricus, family Lutjanidae), jobfish [Pristipomoides typus (P. typus), family Lutjanidae], ribbonfish [Chirocentrus dorab (C. dorab) and Trichiurus lepturus (T. lepturus), family Trichuridae] and catfish [Arius polystaphylodon (A. polystaphylodon), family Ariidae]. Because of their importance, the exploitation of these species should be well managed. Generally to manage human exploitation of resources, it is necessary to know how much can be safely taken without depleting them, and without otherwise negatively impacting the environment. In case of fishing when discussing the limits of exploitation of the fish stocks, the concept of maximum sustainable yield (MSY) should be considered as a key tool for fisheries management. MSY for a given fish stock means the highest possible annual catch that can be sustained over time, by keeping the stock at the level producing maximum growth[4]. The MSY refers to a hypothetical equilibrium state between the exploited population and the fishing activity. MSY as a tool for stock evaluation being easily adopted when data on fishing effort and catch are available from which catch per unit effort (CPUE) could be analysed over a range of fishing season[4]. In Oman, data on catches in weights and number of fishing boats (fishing effort) are available in statistical fishery book issued annually by ministry of agriculture and Fishery Wealth. MSY and surplus production models were discussed and adopted in fishery management in many previous studies[5-20]. One objective of the present study is to investigate the effect of the increase of fishing boats in artisanal fishery on the catch of demesral fishes per boat. Another objective is to estimate the MSY of these fishes. Then it is possible to have an evaluation of their exploitation status. ARTICLE INFO ABSTRACT

The MSY concept in a multi-objective fisheries environment – Lessons from the North Sea

One of the most important goals in current fisheries management is to maintain or restore stocks above levels that can produce the maximum sustainable yield (MSY). However, it may not be feasible to achieve MSY simultaneously for multiple species because of trade-offs that result from interactions between species, mixed fisheries and the multiple objectives of stakeholders. The premise in this study is that MSY is a concept that needs adaptation, not wholesale replacement. The approach chosen to identify trade-offs and stakeholder preferences involved a process of consulting and discussing options with stakeholders as well as scenario modelling with bio-economic and multi-species models. It is difficult to intuitively anticipate the consequences of complex trade-offs and it is also complicated to address them from a political point of view. However, scenario modelling showed that the current approach of treating each stock separately and ignoring trade-offs may result in unacceptable ecosystem, economic or social effects in North Sea fisheries. Setting FMSY as a management target without any flexibility for compromises may lead to disappointment for some of the stakeholders. To treat FMSY no longer as a point estimate but rather as a “Pretty Good Yield” within sustainable ranges was seen as a promising way forward to avoid unacceptable outcomes when trying to fish all stocks simultaneously at FMSY. This study gives insights on how inclusive governance can help to reach consensus in difficult political processes, and how science can be used to make informed decisions inside a multi-dimensional trade-off space.

An evaluation of implementing long-term MSY in ecosystem-based fisheries management: Incorporating trophic interaction, bycatch and uncertainty

Maximum sustainable yield (MSY), often defined in relation to a single species considered in isolation, has long been considered a cornerstone in fisheries management. It is difficult to expand the concept of MSY for the purpose of ecosystem-based fisheries management (EBFM). Here we consider MSY for a fishery in a multispecies fish community by addressing issues of trophic interaction and bycatch, along with parameter uncertainty. A size-spectrum model, which fully considers trophic interactions within the fish community, was used for simulating various fisheries scenarios including a single species fishery, a multispecies stow-net fishery, and a multispecies trawl fishery. Population biomasses, yields, and ecological indicators were used to assess the dynamics of the fishery and fish community status. The single species fishery with no bycatch resulted in a low impact on non-target stocks, but led to the collapse of the target stock at low fishing mortality rates. The stow-net and trawl fisheries had broader ecosystem impacts, but allowed target stocks to be fished at much higher fishing mortality rates with higher yields. Ecological indicators were related non-linearly to fishing mortality, possibly diminishing their effectiveness as management tools. Background resource carrying capacity was found to be a greater source of uncertainty than reproductive efficiency. This study demonstrates that bycatch mortality can play an important role in trophic interactions likely via predation release and depensation, and thus influence the resilience of fisheries to fishing pressure. The study indicates that the combination of mixed fisheries and multispecies effects lead to complex fish community dynamics that may present additional challenges for fisheries management.

Accounting for overfishing in life cycle assessment: new impact categories for biotic resource use

Overfishing is a relevant issue to include in all life cycle assessments (LCAs) involving wild caught fish, as overfishing of fish stocks clearly targets the LCA safeguard objects of natural resources and natural ecosystems. Yet no robust method for assessing overfishing has been available. We propose lost potential yield (LPY) as a midpoint impact category to quantify overfishing, comparing the outcome of current with target fisheries management. This category primarily reflects the impact on biotic resource availability, but also serves as a proxy for ecosystem impacts within each stock. LPY represents average lost catches owing to ongoing overfishing, assessed by simplified biomass projections covering different fishing mortality scenarios. It is based on the maximum sustainable yield concept and complemented by two alternative methods, overfishing though fishing mortality (OF) and overfishedness of biomass (OB), that are less data-demanding. Characterization factors are provided for 31 European commercial fish stocks in 2010, representing 74 % of European and 7 % of global landings. However, large spatial and temporal variations were observed, requiring novel approaches for the LCA practitioner. The methodology is considered compliant with the International Reference Life Cycle Data System (ILCD) standard in most relevant aspects, although harmonization through normalization and endpoint characterization is only briefly discussed. Seafood LCAs including any of the three approaches can be a powerful communicative tool for the food industry, seafood certification programmes, and for fisheries management.

Has the Status of “Maximum Sustainable Yield” Become an International Customary Rule?

The concept of maximum sustainable yield has emerged as a popularly accepted concept for the benefit of the environment, yet the practical implementation of this concept and the dubious acceptance by fisherman of its lawfulness provides the CORE discussion of this article. Customary law exists as a two pillared system depending both on an element of practice in addition to the belief that the behavior in question is lawfully mandated. As such, for customary status to apply to maximum sustainable yield, this requires both pillars. This article therefore evaluates the application of the customary status to maximum sustainable yield and in doing so, demonstrates that maximum sustainable yield is itself an implementation of the greater notion of sustainable development as a whole.

Preventing overfishing: evolving approaches and emerging challenges

Abstract Sissenwine, M. M., Mace P. M., and Lassen, H. J. 2014. Preventing Overfishing: Evolving Approaches and Emerging Challenges. – ICES Journal of Marine Science, 71: 153–156. The evolution of fishery management frameworks to prevent overfishing is the theme of the eight papers that follow in this issue of the ICES Journal of Marine Science. The current paper describes common elements of the frameworks. All the frameworks are based on the maximum sustainable yield concept. Frameworks to prevent overfishing have evolved to be increasingly prescriptive. This evolution probably reflects past abuse of flexibility which led to overfishing. The outcome has been a decline in the proportion of stocks suffering from overfishing. However, loss of flexibility may result in large foregone yields from multispecies fisheries, create a mis-match between the expectations for scientific information and the realities of scientific uncertainty, and fail to recognize ecosystem dynamics.

A medium‐term, stochastic forecast model to support sustainable, mixed fisheries management in the Mediterranean Seaa

A medium-term (10 year) stochastic forecast model is developed and presented for mixed fisheries that can provide estimations of age-specific parameters for a maximum of 10 stocks and 10 fisheries. Designed to support fishery managers dealing with complex, multi-annual management plans, the model can be used to quantitatively test the consequences of various stock-specific and fishery-specific decisions, using non-equilibrium stock dynamics. Such decisions include fishing restrictions and other strategies aimed at achieving sustainable mixed fisheries consistent with the concept of maximum sustainable yield (MSY). In order to test the model, recently gathered data on seven stocks and four fisheries operating in the Ligurian and North Tyrrhenian Seas are used to generate quantitative, 10 year predictions of biomass and catch trends under four different management scenarios. The results show that using the fishing mortality at MSY as the biological reference point for the management of all stocks would be a strong incentive to reduce the technical interactions among concurrent fishing strategies. This would optimize the stock-specific exploitation and be consistent with sustainability criteria.

Size matters: Short term loss and long term gain in a size-selective fishery

The maximum sustainable yield concept (MSY) and the ecosystem approach to fisheries management (EAFM) have been recently adopted by the European Commission with the objective to achieve, over the long term, the highest possible sustainable yield from a given exploited stock. In this context, a fishing mortality MSY reference level (i.e., FMSY) should be defined, taking into account recruitment, growth and natural mortality under current or recent ecosystem conditions. Thus, FMSY is used as a generic term for a robust estimate of a fishing mortality level that is associated with high sustainable yield in the long term, assuming the current harvesting regime in terms of size selectivity. In this study, using the Eastern Baltic cod as an example, we challenge this rather simplified view showing that by using a different harvest selectivity and thus changing the size range of harvested cod, it is possible to largely increase the yield and revenue from the fishery compared to the fishing mortality stipulated in the management plan (i.e., FMSY), while assuring sustainable high yield in the long term. Thus, implementing the MSY concept in terms of fishing mortality but neglecting selective harvesting effects will not achieve high long term sustainable yield for Eastern Baltic cod. The combination of size selective harvesting and economic reasoning may offer an important tool for the management of marine resources by potentially providing a common currency for the different stakeholders and offer guidance to achieve long term sustainability and human well-being. This would represent the natural step forward in the implementation of EAFM and MSY concepts.

The Persistence of a Concept: Maximum Sustainable Yield

Abstract This essay explores the persistence of the concept of maximum sustainable yield (MSY) in global multilateral fishing law. It argues that MSY has contributed to the unsustainable governance of fishing activities by focusing on open access and catch-based management, instead of effort-based management. In response to the dire state of world fish stocks, it has been proposed to cut subsidies to the sector, restrict trade in endangered fish species, install marine protected areas and mainstream the Food and Agriculture Organization’s (FAO) ecosystem approach to fisheries (EAF). This essay proposes that the FAO’s EAF, which links in to social-ecological resilience thinking, suggests a new philosophy for fisheries management that offers a basis for introducing the aforementioned measures.

Assessment of an artisanal shrimp fishery of Litopenaeus vannamei in a lagoon-estuarine system based on the concept of maximum sustainable yield

La aparente simplicidad del concepto del modelo de produccion excedente ha motivado su uso amplio por los responsables de la ordenacion de la explotacion de stocks de camaron costero. Sin embargo, no se ha usado para la evaluacion de poblaciones de camaron en sistemas integrados por lagunas costeras y estuarios de pesquerias cuya estructura solo incluye embarcaciones pequenas restringidas a las lagunas y los estuarios poco profundos. En este estudio el concepto de Rendimiento Maximo Sostenible (RMS) es usado como base para la evaluacion de una pesqueria de camaron (Litopenaeus vannamei) en el sistema lagunar-estuarino Carretas-Pereyra, del Golfo de Tehuantepec, Mexico. Se aplico un modelo dinamico de biomasa para analizar la Captura por Unidad de Esfuerzo (CPUE) de 1983-2006. En la captura comercial se identificaron dos tipos principales de metodos de pesca: esparavel (o atarraya) y encierro estacional. La maxima produccion de camaron (806 t) se registro en 1987, despues de este ano la CPUE adquirio una tendencia negativa. A partir de 1995 el esfuerzo se mantuvo constante pero el patron de captura continuo decreciente. La produccion total observada desde el 2000 se encuentra por debajo (58% promedio) del RMS estimado, 248.393 kg ano-1. El Esfuerzo Observado (505 embarcaciones) supero en un 45% al Esfuerzo Estimado en el RMS (ERMS = 349 embarcaciones). Los resultados sugieren condiciones de sobreexplotacion del stock de camaron, un patron de decremento en la abundancia y un serio riesgo de colapso economico de la pesqueria en el area de estudio.

The Maximum Sustainable Yield of Artisanal Fishery in Zanzibar: A Cointegration Approach

The objective of this study is to analyze the scope for expanding theartisanal fishery in Zanzibar and to present cointegration as an econometricmethod to estimate the maximum sustainable yield (MSY) in fishery. For thatpurpose the Schaefer and Fox surplus production models are considered.Application of cointegration is discussed to test whether there is atendency to long run equilibrium between catch and effort as assumed bythe surplus production models and implied by the MSY concept. Moreover,estimation of the parameters is dealth with. Application to data relating toartisanal fishery in Zanzibar shows that there is support for a Fox model.Moreover, we find that the current catch is only about 40 percent of theestimated MSY, but the prevalent effort is about two times bigger than theestimated optimum effort. It appears therefore that the fishery in Zanzibaris biologically overfished.