Surplus production models: a practical review of recent approaches

Cousido‐Rocha, Marta; Pennino, María Grazia; Izquierdo, Francisco; Paz, Anxo; Lojo, Davinia; Tifoura, Amina; Zanni, Mohamed Yosri; Cerviño, Santiago

doi:10.1007/s11160-022-09731-w

Cited by 13 publications

(9 citation statements)

References 55 publications

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“…The SPiCT model, unlike other methods used for data-limited stocks, takes the history of the fishery into account, does not analyze each year independently (Cousido-Rocha et al, 2022b), and quantifies parameter uncertainty. At the same time, the contrast in the input data is important for a robust SPiCT assessment, i.e.…”

Section: Discussionmentioning

confidence: 99%

First Maximum Sustainable Yield advice for the Nephrops norvegicus stocks of the Northwest Iberian coast using stochastic Surplus Production model in Continuous Time (SPiCT)

et al. 2023

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The assessment of the status of fisheries resources is pivotal due to the importance of marine resources in global food security and to halt the ongoing decline in marine biodiversity. Norway lobster (Nephrops norvegicus) is one of the most valuable resources in the Northeast Atlantic. However, overfishing has caused the decline of several Nephrops stocks over the last decades, particularly in the Nephrops Functional Units (FUs) 25 (NW Spain), 26-27 (NW Spain and North Portugal) and 31 (Cantabrian Sea, North Spain). Since 2003, the information provided by the very low level of landings and fishing effort of these three stocks was insufficient to carry out an adequate analytical assessment, so the base of the assessment has been the trends from commercial catch per unit effort (CPUE). The objective of this study was to carry out the first assessment of these three stocks with an analytical MSY-based model. A review of the available data was made and the stochastic Surplus Production Model in Continuous Time (SPiCT) was fitted for each FU. The results indicate an extremely low biomass for FUs 25 and 26-27 since the mid-nineties well below the reference points. For FU 31, on the other hand, estimated biomass is larger. Our findings also identified long-term temporal and spatial changes in the population dynamic of Nephrops in the Northwest Iberian coast. The results were compare with those obtained in the same stocks with other data-limited methods. Also the role of abiotic factors on the observed dynamic of the stocks was explored. The results of this study are not only relevant for the sustainable exploitation of Norway lobster stocks off the Northwest Iberian coast but provide valuable insights into the suitability and limitations of production models for the assessment of crustacean stocks in general.

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Section: Discussionmentioning

confidence: 99%

First Maximum Sustainable Yield advice for the Nephrops norvegicus stocks of the Northwest Iberian coast using stochastic Surplus Production model in Continuous Time (SPiCT)

et al. 2023

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“…This provides an opportunity to develop and apply a more unified assessment framework and to obtain a better picture of stock status. Surplus production models provide a suitable alternative and, due to improved statistical methodology and user-friendly software interfaces are increasing in popularity (Cousido – Rocha et al 2022). Despite their simplicity, SPMs are widely used for assessing data-limited stocks (Wang et al 2014; Cousido-Rocha et al 2022) and are among the simplest of full stock assessment tools which can inform managers about reference points, stock size and recommended harvest rates.…”

Section: Discussionmentioning

confidence: 99%

“…Surplus production models provide a suitable alternative and, due to improved statistical methodology and user-friendly software interfaces are increasing in popularity (Cousido – Rocha et al 2022). Despite their simplicity, SPMs are widely used for assessing data-limited stocks (Wang et al 2014; Cousido-Rocha et al 2022) and are among the simplest of full stock assessment tools which can inform managers about reference points, stock size and recommended harvest rates. In some cases, they can be more robust than parameter rich age-structured models (Ludwig and Walters 1985, 1989).…”

Section: Discussionmentioning

confidence: 99%

Status and future perspectives for pikeperch (Sander lucioperca) stocks in Europe

Jakubavičiūtė

Arula

Dainys

et al. 2022

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Pikeperch (Sander lucioperca) is a European fresh and brackish water piscivorous fish, important as both a key predator and a valuable commercial and recreational fisheries species. There are concerns that some stocks are depleted due to overfishing and environmental changes. We review data collection and population assessments currently used for nine pikeperch stocks across six European countries and apply a unified assessment framework to evaluate population status and trends. For this we first standardised commercial, scientific, and recreational catch-per-unit-effort (CPUE) and catch time series and then applied Bayesian surplus production models. Our results showed that three stocks (including two in the Baltic Sea) were strongly depleted, with estimated biomasses considerably lower than the biomass at maximum sustainable yield (Bmsy). Other stocks were either close or higher than their estimated Bmsy. Looking at the trends, we find that four stocks (Lake Oulujarvi, Kvadofjarden, Lake Peipsi and Lipno) showed increasing biomass trends and two (Curonian Lagoon, Galtfjarden) had a strong decline in biomass. In most cases the stocks with clear signs of recovery were also those for which strong management strategies have been implemented. We find that, despite pikeperch being one of the most valuable inland fisheries, formalised stock assessments and regular surveys remain rare. Importantly, although most stocks are strongly targeted by recreational fishing, estimates of recreational catch are highly uncertain. We conclude that data limited stock assessment methods are useful for assessing fish population status and highlight an urgent need to improve pikeperch scientific monitoring and assessment of recreational catches.

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“…The main output of the SPiCT model used in this study was the estimated time series of relative biomass (B t /B MSY ), which is less sensitive to the choice of biomass representative of the stock [22] and, in fact, is considered a robust estimator of population dynamics [42]. The uncertainty in the relative biomass time series estimates was much lower by assuming a Schaefer-type production curve.…”

Section: Methodological Considerationsmentioning

confidence: 99%

Stochastic Modelling to Assess External Environmental Drivers of Atlantic Chub Mackerel Population Dynamics

et al. 2022

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The population dynamics of small and middle-sized pelagic fish are subject to considerable interannual and interdecadal fluctuations in response to fishing pressure and natural factors. However, the impact of environmental forcing on these stocks is not well documented. The Moroccan Atlantic coast is characterized by high environmental variability due to the upwelling phenomenon, resulting in a significant abundance and variation in the catches of small and middle-sized pelagic species. Therefore, understanding the evolution of stock abundance and its relationship with different oceanographic conditions is a key issue for fisheries management. However, because of the limited availability of independent-fishery data along the Moroccan Atlantic coast, there is a lack of knowledge about the population dynamics. The main objective of this study is to test the correlation between the environment conditions and the stock fluctuations trends estimated by a stock assessment model that does not need biological information on growth, reproduction, and length or age structure as input. To achieve this objective, the fishery dynamics are analyzed with a stochastic surplus production model able to assimilate data from surveys and landings for a biomass trend estimation. Then, in a second step, the model outputs are correlated with different environmental (physical and biogeochemical) variables in order to assess the influence of different environmental drivers on population dynamics. This two-step procedure is applied for chub mackerel along the Moroccan coast, where all these available datasets have not been used together before. The analysis performed showed that larger biomass estimates are linked with periods of lower salinity, higher chlorophyll, higher net primary production, higher nutrients, and lower subsurface oxygen, i.e., with an enhanced strength of the upwelling. In particular, acute anomalies of these environmental variables are observed in the southern part presumably corresponding to the wintering area of the species in the region. The results indicate that this is a powerful procedure, although with important limitations, to deepen our understanding of the spatiotemporal relationships between the population and the environment in this area. Moreover, once these relationships have been identified, they could be used to generate a mathematical relationship to simulate future population trends in diverse environmental scenarios.

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Surplus production models: a practical review of recent approaches

Abstract: A time series of associated catch data (observations of commercial catches).

Cited by 13 publications

References 55 publications

First Maximum Sustainable Yield advice for the Nephrops norvegicus stocks of the Northwest Iberian coast using stochastic Surplus Production model in Continuous Time (SPiCT)

First Maximum Sustainable Yield advice for the Nephrops norvegicus stocks of the Northwest Iberian coast using stochastic Surplus Production model in Continuous Time (SPiCT)

Status and future perspectives for pikeperch (Sander lucioperca) stocks in Europe

Stochastic Modelling to Assess External Environmental Drivers of Atlantic Chub Mackerel Population Dynamics

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