Comparative performance of data-poor CMSY and data-moderate SPiCT stock assessment methods when applied to data-rich, real-world stocks

2020 ◽  
Author(s):  
Paul Bouch ◽  
Cóilín Minto ◽  
Dave G Reid
Keyword(s):  
Stock Assessment ◽  
Assessment Methods ◽  
Production Model ◽  
Fishing Mortality ◽  
Comparative Performance ◽  
Fish Stocks ◽  
Surplus Production ◽  
Stock Biomass ◽  
Surplus Production Model ◽  
The Status

Abstract All fish stocks should be managed sustainably, yet for the majority of stocks, data are often limited and different stock assessment methods are required. Two popular and widely used methods are Catch-MSY (CMSY) and Surplus Production Model in Continuous Time (SPiCT). We apply these methods to 17 data-rich stocks and compare the status estimates to the accepted International Council for the Exploration of the Sea (ICES) age-based assessments. Comparison statistics and receiver operator analysis showed that both methods often differed considerably from the ICES assessment, with CMSY showing a tendency to overestimate relative fishing mortality and underestimate relative stock biomass, whilst SPiCT showed the opposite. CMSY assessments were poor when the default depletion prior ranges differed from the ICES assessments, particularly towards the end of the time series, where some stocks showed signs of recovery. SPiCT assessments showed better correlation with the ICES assessment but often failed to correctly estimate the scale of either F/FMSY of B/BMSY, with the indices lacking the contrast to be informative about catchability and either the intrinsic growth rate or carrying capacity. Results highlight the importance of understanding model tendencies relative to data-rich approaches and warrant caution when adopting these models.

scholarly journals UPAYA MEMBANGUN KEMBALI DAN PEMULIHAN STOK IKAN PELAGIS KECIL DI LAUT JAWA

2019 ◽  
Vol 25 (3) ◽  
pp. 179
Author(s):  
Suherman Banon Atmaja ◽  
Duto Nugroho
Keyword(s):  
Direct Reduction ◽  
Production Model ◽  
Purse Seine ◽  
North Coast ◽  
Fish Stocks ◽  
Surplus Production ◽  
Stock Status ◽  
Surplus Production Model ◽  
The Status ◽  
Stock Recovery

Tujuan utama makalah ini adalah mengevaluasi kondisi  stok ikan pelagis kecil (dengan ikan layang Decapterus spp. sebagai acuan) sebagai pembangkit ekonomi di pantai Utara Jawa perairan laut Jawa WPPNRI 712. Analisis dilakukan sejalan dengan tren penurunan aktivitas penangkapan kapal pukat cincin yang berpangkalan di Pekalongan Jawa Tengah yang telah berlangsung selama hampir dua dekade. Teori klasik tentang penangkapan ikan mengisyaratkan bahwa pemulihan populasi ikan dapat berlangsung cepat jika penangkapan ikan dihentikan pada rentang waktu tertentu.  Analisis menggunakan pendekatan surplus produksi non-ekuilibrium dengan bantuan perangkat aplikasi ASPIC 7 dan Kobe plot digunakan untuk  memetakan perubahan arah status stok ikan pelagis kecil yang berkaitan langsung dengan perilaku perkembangan perikanan pukat cincin di laut Jawa pada kurun waktu 1976 - 2014.  Hasil penelitian menunjukkan bahwa penurunan drastis baik jumlah armada pukat cincin maupun aktivitas penangkapannya akibat rendahnya peluang keberhasilan dan tingginya investasi operasional hampir dua dekade  telah telah memberikan peluang terhadap pemulihan stok secara alamiah menuju tingkat biomassa optimal.  Pergerakan status biomasa dan mortalitas penangkapan ikan pelagis kecil secara tahunan yang ditampilkan melalui penggunaan Kobe plot memberikan indikasi bahwa kondisi stok ikan setelah tahun 2015 mengarah pada status yang cenderung baik. The main objective of this paper is to evaluate the status and trend of small pelagic fish stocks (Decapterus spp.) as a major driver of economics in north coast of Java correspond to a direct reduction of purse seine fishing activities at around two decades. Classical theory of fishing suggests that rapid population recovery occurs when fishing pressures is reduced. These phenomenons were analyzed by applying non-equilibrium surplus production model incorporate covariance of the programs package of Aspic 7.  Simple Kobe plots were also applied to track the annual trend of stock status directly which presumably related to the course of fisheries development.  The results showed that drastic decline of fishing pressures of both number of purse seine fleet and their activity within the last decade provided an opportunity of stock recovery at optimum biomass levels. Applying simple Kobe plots indicates the stock status and trend in 2015 relatively in rebuilding condition

scholarly journals Population changes in rattail species on the Chatham Rise

2021 ◽  
Author(s):  
◽  
Kathleen Large
Keyword(s):  
Maximum Likelihood ◽  
Stock Assessment ◽  
Production Model ◽  
Likelihood Method ◽  
Model Parameters ◽  
Important Species ◽  
Surplus Production ◽  
Surplus Production Model ◽  
Abundance Indices ◽  
The Impact

<p>The aim of this project was to conduct a stock assessment to determine the population dynamic characteristics of rattail species taken as bycatch in the hoki, hake and ling fishery on the Chatham Rise. No quantitative assessment of the current size of rattail populations , and how these may have changed over time, has been carried out before. There is interest in the need to quantify the impact of commercial fishing on the rattail populations, as rattails (Macrouridae family) are considered to be an ecologically important species complex in the deep ocean, and there may be the potential for the development of a commercial fishery based on their value as processed fishmeal. The minimum data required for a stock assessment are an abundance index and a catch history. Abundance indices are available for over 20 species of rattail produced from scientific surveys conducted annually on the Chatham Rise since 1992. Catch histories for individual rattail species in the same area are not available. A method was developed to reconstruct commercial catches of rattails from commercial effort data and survey catch and effort data. A surplus production model was fitted to the reconstructed catch data and survey abundance indices, using maximum likelihood and Bayesian methods to estimate model parameters and uncertainty. A surplus production model has two components: an observation model for abundance indices and a process model for population dynamics. Maximum likelihood estimation was applied to a model that specified errors for the observations only, and this produced estimates that had wide confidence intervals. A Bayesian approach was then taken to fit a statespace version of the model that incorporates errors associated with the observation and process models. While the Bayesian method produced more plausible parameter estimates (in comparison to the maximum likelihood method) and parameter uncertainty was reduced, our analysis indicated the posterior estimates were highly sensitive to the specification of different priors. There may be several reasons for these results, including: the small number of observations, lack of contrast in the data and mis-specification of the model. Meaningful estimates of the absolute size of rattail populations are not possible with these results, where estimates can vary by orders of magnitude depending on prior specification. This implies that more work needs to be done to develop more effective methods that can be used to help inform decisions regarding the management of these fish populations. Improving data collection, investigating informative priors and extending/respecifying the model are considered worthwhile avenues of future work to improve stock assessments of rattails.</p>

scholarly journals Penentuan Status Pemanfaatan dan Pengelolaan Ikan Tongkol (Auxis rochei) yang Tertangkap di Perairan Bolaang-Mongondow Selatan dan Bolaang-Mongondow Timur Sulawesi Utara

d'CARTESIAN ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Ladi Beatriex Deeng ◽  
Hanny A H Komalig ◽  
John S Kekenusa
Keyword(s):  
Maximum Sustainable Yield ◽  
Production Model ◽  
Model Data ◽  
Biological Resource ◽  
Surplus Production ◽  
North Sulawesi ◽  
Surplus Production Model ◽  
The Status ◽  
Level Of Effort

LADI BEATRIEX DEENG. Determination of Utilization and Management Status of Bonito (Auxis Rochei) Caught in South Bolaang-Mongondow and East Bolaang-Mongondow Waters of North Sulawesi. Supervised by Mr. JOHN S. KEKENUSA as main supervisor, and Mr. HANNY A. H. KOMALIG as co-supervisor.Bonito (Auxis rochei), needs to be managed properly because even though it is a renewable biological resource, it can experience overfishing, depletion or extinction. One way to approach the management of fish resources is by modeling. The analysis was carried out aiming to determine the status of utilization and management of bonito and maximum sustainable yield (MSY) using the Surplus Production Model. Data on catching and efforts to catch bonito is collected from the Marine and Fisheries Service of South Bolaang-Mongondow Regency and East Bolaang-Mongondow of North Sulawesi. The surplus production model that can be used to determine the catch of bonito is the Schaefer model. The maximum sustainable catch of bonito is 869.556 tons per year, obtained at the level of catching effort of 933 trips. For 2017 the level of utilization is 64.95 % so that production can still be increased, with a level of effort of 73.74 % indicating the level of effort that is not optimal and can still be increased. Keywords : Bonito, Surplus Production Model, South Bolaang-Mongondow and   East Bolaang-Mongondow Regency

scholarly journals Marine Sustainable Yield Analysis of Pelagic Fisheries in Sea Based on Catch Landing data From Tumumpa Fishery Harber, Manado North Sulawesi

2017 ◽  
Vol 6 (1) ◽  
pp. 21
Author(s):  
David Y Rumambi ◽  
Unstain N. W. J. Rembet ◽  
Joudy R. R. Sangari
Keyword(s):  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Pelagic Fish ◽  
Production Model ◽  
Sustainable Yield ◽  
Research Activity ◽  
Fish Stocks ◽  
Surplus Production ◽  
North Sulawesi ◽  
Surplus Production Model

This research activity took place in Manado City, North Sulawesi Province with activities centered on the Tumumpa Fishery Harbor (PPP). The data were recorded from capture fisheries activity conducted in the Sulawesi Sea and its surroundings landed in the Tumumpa Fishery Harbor. The purpose of this study was to analyze the stock value and Maximum Sustainable Yield (MSY) of pelagic fish in the Sulawesi Sea based on the approach of the surplus production model (Model Schaefer). This research is expected to be used as a consideration in the management of pelagic fish stocks in the Sulawesi Sea, and can be used as a basis for further research. This research uses secondary data collection method in the form of statistical document and record available. The data taken, including fish catch and fishing effort or effort (trip), from 2012 to 2016 (5 years). The results show that production value is inversely proportional to the value of effort, where the value of production from 2012 to 2016 has decreased every year, while the value of effort from 2012 to 2016 has increased. This condition indicates that the presence of pelagic fish stocks in the Sulawesi Sea and surrounding areas has been and is experiencing a decline that impacts on the decrease of production every year with a large percentage and this condition also indicates the occurrence of potentially overfishing. The value of MSY utilization of capture fishery resources in the Sulawesi Sea based on Tumumpa Fishery Harbor data were 16,305.45 tons / year for HMSY and 1,664,59 trips / year for EMSY, with TAC of 13,044.36 tons / year.Keywords :  Capture fishery, MSY, Pelagic, Surplus Production Model, Tumumpa ABSTRAK Kegiatan penelitian ini berlangsung di Kota Manado, Provinsi Sulawesi Utara dengan kegiatan berpusat di Pelabuhan Perikanan Pantai (PPP) Tumumpa Manado. Aktivitas perikanan tangkap yang ditelaah berlangsung di kawasan perairan Laut Sulawesi dan sekitarnya berdasarkan data PPP Tumumpa Manado. Tujuan dari penelitian ini adalah untuk menganalisis nilai stok dan Maximum Sustainable Yield (MSY) ikan pelagis di Laut Sulawesi berdasarkan pendekatan model produksi surplus (Model Schaefer). Penelitan ini diharapkan dapat digunakan sebagai bahan pertimbangan dalam pengelolaan stok ikan pelagis di Laut Sulawesi dan sekitarnya, serta dapat digunakan sebagai dasar untuk penelitian selanjutnya. Penelitian ini menggunakan metode pengumpulan data sekunder berbentuk dokumen. Data yang diambil adalah data tangkapan ikan dan upaya penangkapan ikan atau effort (trip), dari tahun 2012 sampai dengan 2016 (5 Tahun). Hasil penelitian menunjukkan nilai produksi berbanding terbalik dengan nilai effort, di mana nilai produksi dari tahun 2012 sampai 2016 mengalami penurunan setiap tahunnya, sedangkan nilai effort dari tahun 2012 sampai tahun 2016 mengalami peningkatan. Kondisi yang terjadi ini mengindikasikan bahwa keberadaan stok ikan pelagis di Laut Sulawesi dan sekitarnya telah dan sedang mengalami penurunan yang berdampak pada penurunan produksi setiap tahun dengan persentase yang cukup besar di mana kondisi ini mengindikasikan terjadinya overfishing. Nilai MSY pemanfaatan sumber daya perikanan tangkap di Laut Sulawesi berdasarkan data PPP Tumumpa Manado sebesar 16.305,45 ton/tahun untuk HMSY, dan 1.664,59 trip/tahun untuk EMSY, dengan TAC sebesar 13.044,36 ton/tahun.Kata Kunci: Perikanan Tangkap, MSY, Pelagis, Model Produksi Surplus, Tumumpa

scholarly journals PENENTUAN STATUS PEMANFAATAN DAN SKENARIO PENGELOLAAN IKAN CAKALANG (Katsuwonus pelamis) YANG TERTANGKAP DI PERAIRAN BOLAANG-MONGONDOW SULAWESI UTARA

2014 ◽  
Vol 14 (1) ◽  
pp. 9 ◽  
Author(s):  
John S Kekenusa ◽  
Victor N.R Watung ◽  
Djoni Hatidja
Keyword(s):  
Maximum Sustainable Yield ◽  
Production Model ◽  
Sustainable Yield ◽  
Potential Yield ◽  
Katsuwonus Pelamis ◽  
Effort Level ◽  
Surplus Production ◽  
North Sulawesi ◽  
Surplus Production Model ◽  
The Status

PENENTUAN STATUS PEMANFAATAN DAN SKENARIO PENGELOLAANIKAN CAKALANG (Katsuwonus pelamis) YANG TERTANGKAP DI PERAIRANBOLAANG-MONGONDOW SULAWESI UTARAABSTRAKIkan Cakalang (Katsuwonus pelamis L.), perlu dikelola dengan baik sebagai sumber daya alam terbarukan, tetapi semakin habis atau punah. Salah satu pendekatan dalam pengelolaan sumberdaya ikan adalah dengan pemodelan. Analisis dilakukan, bertujuan untuk mendapatkan model terbaik untuk model surplus produksi adalah Maximum Sustainable Yield (MSY), dan untuk mendapatkan pemanfaatan cakalang dan tingkat usaha. Data yang digunakan untuk model produksi surplus dikumpulkan dari data hasil tangkapan cakalang yang disediakan oleh Dinas Kelautan Dan Perikanan Kabupaten Bolaang Mongondow Provinsi Sulawesi Utara. Model terbaik Surplus Produksi dapat digunakan untuk menilai potensi hasil cakalang adalah  model Fox. Upaya optimal per tahun secara biologi EMSY adalah 3.876 perjalanan. Hasil optimal secara biologi CMSY 1,505.00 ton per tahun. Tingkat pemanfaatan untuk tahun 2005 adalah 124,48%, dengan tingkat usaha 110,96%. Hasil tangkapan untuk tahun 2005 sudah di atas nilai MSY, yang menunjukkan overfishingKata kunci: ikan cakalang, Model surplus produksi, Maksimum Sustainable Yield,Bolaang MonogndowDETERMINATION OF THE STATUS OF UTILIZATION AND MANAGEMENTSCENARIOS SKIPJACK (Katsuwonus pelamis L.) CAUGHT IN THEBOLAANG MONGONDOW BEACH, NORTH SULAWESIABSTRACTSkipjack (Katsuwonus pelamis L.), needs to be managed well as a renewable natural resources, but vunerable to depletion or extinction. One approach in fish resource management is by modeling. Analysis were carried out, aimed to get the best model for surplus production model, to assess the Maximum Sustainable Yield (MSY), and to get the skipjack utilization and effort level. Data used for surplus production model were collected from skipjack landings data provided by Marine and Fisheries Service (Dinas Kelautan dan Perikanan) of Bolaang-Mongondow Regency and North Sulawesi Province. The best Surplus Production Model that can be used to assess the skipjack potential yield is the Fox model. The optimum effort per year biologically EMSY is 3,876 trips. The optimum yield biologically CMSY is 1,505.00 tons per year. Utilization level for 2005 was 124.48 %, with effort level 110.96 %. The catch for 2005 had already above the MSY value, which shows an overfishing.Keywords : Skipjack, Surplus Production Model, Maximum Sustainable Yield, Bolaang Mongondow

scholarly journals PENENTUAN STATUS PEMANFAATAN DAN SKENARIO PENGELOLAAN IKAN TONGKOL (Auxis rochei) YANG TERTANGKAP DI PERAIRAN KABUPATEN SIAU-TAGULANDANG-BIARO SULAWESI UTARA

2014 ◽  
Vol 14 (2) ◽  
pp. 136
Author(s):  
John S. Kekenusa ◽  
Sendy B. Rondonuwu ◽  
Marline S. Paendong ◽  
Winsy Ch.D. Weku
Keyword(s):  
Maximum Sustainable Yield ◽  
Production Model ◽  
Sustainable Yield ◽  
Management Scenarios ◽  
Potential Yield ◽  
Effort Level ◽  
Surplus Production ◽  
North Sulawesi ◽  
Surplus Production Model ◽  
The Status

ABSTRAK Ikan tongkol (Auxis rochei), perlu dikelola dengan baik karena walaupun sebagai sumberdaya alam terbarukan, namun dapat mengalami deplesi ataupun kepunahan. Salah satu pendekatan dalam pengelolaan sumberdaya ikan ialah dengan pemodelan. Analisis dilakukan bertujuan untuk mendapatkan model terbaik untuk model produksi surplus guna mengetahui tangkapan maksimum lestari (MSY), tingkat pemanfaatan, dan pengupayaan ikan tongkol. Data hasil tangkapan dan upaya tangkap ikan tongkol dikumpulkan dari Dinas Kelautan dan Perikanan Kabupaten Siau-Tagulandang-Biaro dan Dinas Kelautan dan Perikanan Provinsi Sulawesi Utara Sulawesi. Model Produksi Surplus terbaik, yang digunakan untuk menilai potensi ikan tongkol ialah model Schaefer. Upaya optimal (EMSY)sebesar 5436 trip per tahun. Hasil tangkapan optimal CMSY sebesar 1040,94 ton per tahun. Tingkat pemanfaatan untuk tahun 2013 ialah 103,80 %, dengan tingkat pengusahaan sebesar 110,56 %, yang menunjukkan terjadi tangkap-lebih (overfishing). Kata Kunci : Ikan  tongkol, Model Produksi Surplus,Tangkapan Maksimum Lestari, Siau-Tagulandang-Biaro DETERMINATION OF THE STATUS OF UTILIZATION AND MANAGEMENT SCENARIOS BONITO (Auxis rochei) CAUGHT IN THE SIAU-TAGULANDANG-BIARO REGENCY NORTH SULAWESI ABSTRACT Bonito (Auxis rochei), needs to be  managed well as a renewable natural resources, but vunerable to depletion or extinction. One approach in fish resource management is by modeling. Analysis were carried out, aimed to get the best model for surplus production model, to assess the Maximum Sustainable Yield (MSY), and to get the bonito utilization and effort level. Data used for surplus production model were collected from bonito landings data provided by Marine and Fisheries Service (Dinas Kelautan dan Perikanan) of  Siau-Tagulandang-Biaro Regency and North Sulawesi Province. The best Surplus Production Model that can be used to assess the bonito potential yield is the Schaefer model. The optimum effort biologically EMSY is 5,436 trips per year. The optimum yield biologically CMSY is 1,040.94 tons per year. Utilization level for 2013 was103.80 %, with effort level 110.56 %. The catch for 2013 had already above the MSY value, which shows an  overfishing. Keywords : Bonito, Surplus Production Model, Maximum Sustainable Yield, Siau-Tagulandang-Biaro

scholarly journals Population changes in rattail species on the Chatham Rise

2021 ◽  
Author(s):  
◽  
Kathleen Large
Keyword(s):  
Maximum Likelihood ◽  
Stock Assessment ◽  
Production Model ◽  
Likelihood Method ◽  
Model Parameters ◽  
Important Species ◽  
Surplus Production ◽  
Surplus Production Model ◽  
Abundance Indices ◽  
The Impact

<p>The aim of this project was to conduct a stock assessment to determine the population dynamic characteristics of rattail species taken as bycatch in the hoki, hake and ling fishery on the Chatham Rise. No quantitative assessment of the current size of rattail populations , and how these may have changed over time, has been carried out before. There is interest in the need to quantify the impact of commercial fishing on the rattail populations, as rattails (Macrouridae family) are considered to be an ecologically important species complex in the deep ocean, and there may be the potential for the development of a commercial fishery based on their value as processed fishmeal. The minimum data required for a stock assessment are an abundance index and a catch history. Abundance indices are available for over 20 species of rattail produced from scientific surveys conducted annually on the Chatham Rise since 1992. Catch histories for individual rattail species in the same area are not available. A method was developed to reconstruct commercial catches of rattails from commercial effort data and survey catch and effort data. A surplus production model was fitted to the reconstructed catch data and survey abundance indices, using maximum likelihood and Bayesian methods to estimate model parameters and uncertainty. A surplus production model has two components: an observation model for abundance indices and a process model for population dynamics. Maximum likelihood estimation was applied to a model that specified errors for the observations only, and this produced estimates that had wide confidence intervals. A Bayesian approach was then taken to fit a statespace version of the model that incorporates errors associated with the observation and process models. While the Bayesian method produced more plausible parameter estimates (in comparison to the maximum likelihood method) and parameter uncertainty was reduced, our analysis indicated the posterior estimates were highly sensitive to the specification of different priors. There may be several reasons for these results, including: the small number of observations, lack of contrast in the data and mis-specification of the model. Meaningful estimates of the absolute size of rattail populations are not possible with these results, where estimates can vary by orders of magnitude depending on prior specification. This implies that more work needs to be done to develop more effective methods that can be used to help inform decisions regarding the management of these fish populations. Improving data collection, investigating informative priors and extending/respecifying the model are considered worthwhile avenues of future work to improve stock assessments of rattails.</p>

scholarly journals Censored catch data in fisheries stock assessment

2005 ◽  
Vol 62 (6) ◽  
pp. 1118-1130 ◽  
Author(s):  
T.R. Hammond ◽  
V.M. Trenkel
Keyword(s):  
Stock Assessment ◽  
Recursive Partitioning ◽  
Maximum Sustainable Yield ◽  
Production Model ◽  
Model Parameters ◽  
Commercial Fish ◽  
Surplus Production ◽  
Stock Assessments ◽  
Surplus Production Model ◽  
Simulation Parameters

Abstract Landings statistics can be lower than true catches because many fish are discarded or landed illegally. Since many discards do not survive, treating landings as true catches can lead to biased stock assessments. This paper proposes treating catch as censored by bounding it below by the landings, L, and above by cL (for scalar c > 1). We demonstrate the approach with a simulation study, using a Schaefer surplus production model. Parameters were estimated in a Bayesian framework with BUGS software using two sets of priors. Both the traditional true-catch method and a survey-and-effort method (which was landings free) performed worse on average than the censored approach, as measured by the Bayes risk associated with estimates of maximum sustainable yield (MSY) and of an index of depletion (X). Recursive partitioning (regression trees) was used to associate simulation parameters to best-performing methods, showing that higher commercial fish catchability favoured the censored method at estimating X. In conclusion, censored methods provide a means of dealing with discarding and misreporting that can outperform some traditional alternatives.

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