scholarly journals Assessing Five Major Exploited Tuna Species in India (Eastern and Western Indian Ocean) Using the Monte Carlo Method (CMSY) and the Bayesian Schaefer Model (BSM)

2021 ◽  
Vol 13 (16) ◽  
pp. 8868
Author(s):  
Ubair Nisar ◽  
Rafiya Ali ◽  
Yongtong Mu ◽  
Yu Sun
Keyword(s):  
Indian Ocean ◽  
Stock Assessment ◽  
Western Indian Ocean ◽  
Intrinsic Rate ◽  
Maximum Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Tuna Fish ◽  
Fish Stocks ◽  
The Monte Carlo Method ◽  
The Status

The status of data-limited tuna fishery stocks in India has been tested using the latest and most advanced computerized methods, CMSY and BSM. Five tuna fish stocks from both the Eastern and Western Indian Ocean were assessed using both catch and catch per unit effort (CPUE) details available from 1990 to 2015. Both methods help to calculate the maximum sustainable yield (MSY) and exploitation of MSY relative to biomass (B/BMSY). The results of maximum intrinsic rate (r) and carrying capacity are also estimated. The results revealed that all tuna stocks in both the regions were overfished, with one, the longtail tuna (Thunnus tonggol) in the Western Indian Ocean strongly overfished (B/BMSY = 0.44). Such observations, although still preliminary since the techniques used to produce them are relatively new, often associated with the situation and exploitation of all the stock in question, making the CMSY and BSM methods promising for stock assessment in data-deficit situations. The study concludes that in order to restore the status of these five tuna stocks in both regions, it would be necessary to reduce the fishing pressure.

scholarly journals Application of dynamic factor analysis in the assessment of Iberian anglerfish stocks

2008 ◽  
Vol 65 (7) ◽  
pp. 1362-1369 ◽  
Author(s):  
Manuela Azevedo ◽  
Rafael Duarte ◽  
Fátima Cardador ◽  
Pedro Sousa ◽  
Celso Fariña ◽  
...  
Keyword(s):  
Factor Analysis ◽  
Stock Assessment ◽  
Intrinsic Rate ◽  
Maximum Sustainable Yield ◽  
Dynamic Factor Analysis ◽  
Parameter Estimates ◽  
Dynamic Factor ◽  
Catch Per Unit Effort ◽  
Biomass Dynamic ◽  
Lower Maximum

Abstract Azevedo, M., Duarte, R., Cardador, F., Sousa, P., Fariña, C., Sampedro, P., Landa, J., and Costas, G. 2008. Application of dynamic factor analysis in the assessment of Iberian anglerfish stocks. – ICES Journal of Marine Science, 65: 1362–1369. Dynamic factor analysis (DFA) was applied to six time-series of catch per unit effort data of the Iberian (ICES Divisions VIIIc and IXa) white anglerfish (Lophius piscatorius) and black anglerfish (L. budegassa). Results showed that grouping the abundance indices reflected the fleet's area of exploitation and fish size selection. Two common trends (CTs) were extracted for each species, capturing the main signal of abundance over time. The white anglerfish was assessed using these CTs as input to the biomass dynamic model currently used in the ICES assessment, to investigate whether the approach would reduce the uncertainty in parameter estimates and related quantities. Using the CTs, bias estimates are lower. The current perception of an overexploited stock is unchanged, but a much lower intrinsic rate of biomass increase was estimated, indicating that the biomass recovery might be much slower. A lower maximum sustainable yield, ∼3600 t, was obtained, and this is more consistent with the historical landings trajectory. The application of DFA to stock assessment of anglerfish, presented here for the first time, can be extended to age-based assessments.

scholarly journals Interpreting catch per unit effort data to assess the status of individual stocks and communities

2006 ◽  
Vol 63 (8) ◽  
pp. 1373-1385 ◽  
Author(s):  
Mark N. Maunder ◽  
John R. Sibert ◽  
Alain Fonteneau ◽  
John Hampton ◽  
Pierre Kleiber ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Stock Assessment ◽  
Limited Information ◽  
Catch Per Unit Effort ◽  
Fish Stocks ◽  
Unit Effort ◽  
Strategy Evaluation ◽  
The Status ◽  
Catch Rates ◽  
Management Advice

AbstractDespite being one of the most common pieces of information used in assessing the status of fish stocks, relative abundance indices based on catch per unit effort (cpue) data are notoriously problematic. Raw cpue is seldom proportional to abundance over a whole exploitation history and an entire geographic range, because numerous factors affect catch rates. One of the most commonly applied fisheries analyses is standardization of cpue data to remove the effect of factors that bias cpue as an index of abundance. Even if cpue is standardized appropriately, the resulting index of relative abundance, in isolation, provides limited information for management advice or about the effect of fishing. In addition, cpue data generally cannot provide information needed to assess and manage communities or ecosystems. We discuss some of the problems associated with the use of cpue data and some methods to assess and provide management advice about fish populations that can help overcome these problems, including integrated stock assessment models, management strategy evaluation, and adaptive management. We also discuss the inappropriateness of using cpue data to evaluate the status of communities. We use tuna stocks in the Pacific Ocean as examples.

scholarly journals PENILAIAN STATUS STOK DAN RISIKO EKSPLOITASI PERIKANAN PELAGIS KECIL YANG BERBASIS DI PPI SARANG, REMBANG, JAWA TENGAH

2020 ◽  
Vol 26 (4) ◽  
pp. 189
Author(s):  
Achmad Zamroni ◽  
Heri Widiyastuti ◽  
Suwarso Suwarso
Keyword(s):  
Risk Estimation ◽  
Reference Value ◽  
Maximum Sustainable Yield ◽  
Risk Level ◽  
Fish Stocks ◽  
The Status ◽  
Equilibrium Data ◽  
Java Sea ◽  
Pelagic Fisheries ◽  
Non Equilibrium

Peningkatan strategi pengelolaan perikanan pelagis kecil terutama di perairan Laut Jawa tidak hanya dengan menilai stok ikan dan perikanannya, akan tetapi diperlukan juga menilai risiko dampak dari pengelolaan. Dalam tulisan ini disebutkan status estimasi stok dan risiko yang melebihi hasil tangkapan maksimum yang berkelanjutan/Maximum Sustainable Yieald (MSY) terkait dengan nilai referensi terhadap beberapa tingkat tangkapan alternatif yang dihasilkan dari penilaian stok dan risiko penangkapan. Analisis yang digunakan adalah model dinamika biomassa ikan dengan metode non-equilibrium. Data yang digunakan berasal dari PPI Sarang, Rembang yang merupakan basis perikanan pelagis kecil terbesar di Laut Jawa selain Pekalongan. Hasil analisis menunjukkan bahwa nilai MSY yang diperoleh adalah 13.820 ton yang dihasilkan dari upaya penangkapan sekitar 1.759 trip kapal pukat cincin mini. Jika pemanfaatan perikanan sesuai dengan kondisi saat ini, maka estimasi nilai risiko akan berada pada tingkat risiko tinggi, begitu juga jika tingkat pemanfaatan berada pada nilai MSY nya. Nilai risiko akan turun menjadi sedang-tinggi jika pemanfaatan dikurangi 10% - 20% dari kondisi saat ini. Jika tingkat pemanfaatan dikurangi 30% atau lebih, maka nilai risiko dalam 10 tahun berikutnya akan berada pada kondisi sedang-rendah.Improving the management strategy of small pelagic fisheries, especially in the waters of the Java Sea, not only by assessing fish stocks and fisheries, but also needs to determine the risk of management impacts. In this paper, it is stated that the status of stock and risk estimation that exceeds the Maximum Sustainable Yield (MSY) is related to the reference value in several alternative catch levels resulting from stock and risk assessment. The analysis used is a fish biomass dynamics model with a non-equilibrium method. The data used was from TPI Sarang in Rembang, which is one of the largest small pelagic fisheries bases in the Java Sea. Results show that the MSY value obtained is 13,820 tons resulting from the capture effort of approximately 1,759 mini purse seine trips. Suppose the fishery utilization is in accordance with the current conditions, in that case, the estimated risk value will be at a high-risk level, and also if the utilization level is at the MSY value. The risk value will decrease to moderate-high if utilization is reduced by 10% - 20% from the current condition. If the utilization level is reduced by 30% or more, the next ten-year risk value will be in the medium-low condition.

Stock Assessment and Life History of a Newly Discovered Alaska Surf Clam (Spisula polynyma) Resource in the Southeastern Bering Sea

1981 ◽  
Vol 38 (10) ◽  
pp. 1173-1181 ◽  
Author(s):  
Steven E. Hughes ◽  
Neil Bourne
Keyword(s):  
Bering Sea ◽  
Stock Assessment ◽  
Maximum Sustainable Yield ◽  
North Coast ◽  
Catch Per Unit Effort ◽  
Surf Clam ◽  
The North ◽  
Management Measures ◽  
History Of ◽  
Slow Growing

A 1977 exploratory survey of subtidal clam resources in the southeastern Bering Sea revealed extensive concentrations of Alaska surf clams (Spisula polynyma) along the north coast of the Alaska Peninsula. Using east coast hydraulic clam harvesters, subsequent 1977 and 1978 stock assessment surveys delineated a geographically isolated stock with an estimated exploitable biomass of 329 000 ± 52 000 t and conservatively calculated potential annual yield of 25 017 t (maximum sustainable yield) of whole clams. Production fishing trials at 13 sites in 1978 produced an average catch per unit effort of 815 kg/h with a 1.84-m-wide clam harvester.Life history studies indicated the species is long-lived (25 yr), slow growing (K = 0.135), fully recruited to the spawning population at 8 yr of age, subject to low natural mortality (conservatively calculated as M = 0.19), and attains maximum cohort biomass at ages between 9.4 and 13.0 yr. Biological rationale for management measures is presented.Key words: population assessment, sustained yield, surf clams, Alaska

scholarly journals OVERFISHING AND OVERCAPACITY SMALL SCALE FISHERIES IN SEMARANG CITY

2019 ◽  
Vol 11 (2) ◽  
pp. 427-435
Author(s):  
Jamaludin Malik ◽  
Achmad Fahrudin ◽  
Dietriech Geoffrey Bengen ◽  
Taryono Khodiron
Keyword(s):  
Sustainable Management ◽  
Maximum Sustainable Yield ◽  
Utilization Rate ◽  
Small Scale ◽  
Fishing Gear ◽  
Catch Per Unit Effort ◽  
Small Scale Fisheries ◽  
Surplus Production ◽  
Capacity Level ◽  
The Status

Fisheries in Semarang City are dominated by small-scale fisheries. This is indicated by the use of the largest fishing fleet of 10 gross tons operating near the coast. This study aims to analyze the status of small-scale fisheries in Semarang City for sustainable management. Sustainable management is management that guarantees the availability of natural resources and environmental services for future generations. The study was conducted for three months, namely September-November 2018 in the coastal waters of Semarang City, which was part of the Fisheries Management Region (WPP) 712. The method used in this study is the analysis of time series surplus production, namely data from the catch (ton/year) and the number of fishing gear (unit) within 10 years (2007-2016), to calculate the catch per-unit effort (CPUE), maximum sustainable yield (MSY), optimum effort (fopt), utilization rate (TP) and capacity level (TK). This study was obtained results of a downward trend in CPUE; the existing fishery catch or production in 2016 has exceeded the MSY value is 479 tons/year (Schaefer) and 439.11 tons/year (Fox); utilization rate of more than 100% which is 108-127% (Schaefer) and 118-138% (Fox), so that small-scale fisheries in Semarang City are at the level of over-exploited. Based on the fopt analysis, the number of fishing gear used (fexisting) has exceeded the optimum effort with a fishing capacity exceeding 100%, so that small-scale fisheries in Semarang City have experienced overcapacity.

scholarly journals RESPONSIBLE FISHERIES MANAGEMENT OF MINI PURSE SEINE IN THE LAMPUNG BAY AREA

2017 ◽  
Vol 8 (2) ◽  
pp. 713-728
Author(s):  
Yulia Estmirar Tanjov ◽  
Roza Yusfiandayani ◽  
. Mustaruddin
Keyword(s):  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Pelagic Fish ◽  
Purse Seine ◽  
Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Small Pelagic Fish ◽  
Bay Area ◽  
Fisheries Resources ◽  
The Status

Lempasing is a Coastal Fishing Port (CFP) which located in Bandar Lampung. It is one of the centers of fisheries activities in the city. One of the fishing gear which operated by most of fishermen in Lempasing is mini purse seine. Mini purse seine fishing activities in the Lampung Bay Area and Lempasing CFP is not in accordance with the conditions of the surrounding waters area. The research was conducted in the Lampung Bay Area and Lempasing CFP, Lampung. This study aims to: 1) determine the status of fisheries resources utilization, 2) to describe the dominant fish caught by mini purse seine.  Analysis methods were used in this study namely: 1) Fishing Power Index (FPI), Catch Per Unit Effort (CPUE), and Maximum Sustainable Yield (MSY) to determine the status of fisheries resource utilization. The dominant small pelagic fishes caught were scad fish Selaroides sp., mackerel fish Rastrelliger sp., longnose trevally fish Carangoides chrysophrys. The result showed that Fox model was the best fits models with estimated maximum sustainable yield of 15.5 ton and fishing effort of 992 trip/year for mini purse seine. The longnose trevally fish in lampung bay area in do not exceeded the optimal catch fish condition can be used to sustainably. In these condition is necessary to wisely manage and setting the catches to not exceed the allowable catch of the small pelagic fish, so the stock of small pelagic fish in the Lampung Bay Area can be used sustainably.

scholarly journals RESPONSIBLE FISHERIES MANAGEMENT OF MINI PURSE SEINE IN THE LAMPUNG BAY AREA

2017 ◽  
Vol 8 (2) ◽  
pp. 713
Author(s):  
Yulia Estmirar Tanjov ◽  
Roza Yusfiandayani ◽  
. Mustaruddin
Keyword(s):  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Pelagic Fish ◽  
Purse Seine ◽  
Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Small Pelagic Fish ◽  
Bay Area ◽  
Fisheries Resources ◽  
The Status

<p><em>Lempasing is a Coastal Fishing Port (CFP) which located in Bandar Lampung. It is one of the centers of fisheries activities in the city. One of the fishing gear which operated by most of fishermen in Lempasing is mini purse seine. Mini purse seine fishing activities in the Lampung Bay Area and Lempasing CFP is not in accordance with the conditions of the surrounding waters area. The research was conducted in the Lampung Bay Area and Lempasing CFP, Lampung. This study aims to: 1) determine the status of fisheries resources utilization, 2)</em><em> to describe the dominant fish caught by mini purse seine. </em><em> Analysis methods were used in this study namely: 1) Fishing Power Index (FPI), Catch Per Unit Effort (CPUE), and Maximum Sustainable Yield (MSY) to determine the status of fisheries resource utilization. The dominant small pelagic fishes caught were scad fish <span style="text-decoration: underline;">Selaroides</span> </em>sp<em>., mackerel fish <span style="text-decoration: underline;">Rastrelliger</span> </em>sp<em>., longnose trevally fish <span style="text-decoration: underline;">Carangoides</span> <span style="text-decoration: underline;">chrysophrys</span>. The result showed that Fox model was the best fits models with estimated maximum sustainable yield of 15.5 ton and fishing effort of 992 trip/year for mini purse seine. The longnose trevally fish in lampung bay area in do not exceeded the optimal catch fish condition can be used to sustainably. In these condition is necessary to wisely manage and setting the catches to not exceed the allowable catch of the small pelagic fish, so the stock of small pelagic fish in the Lampung Bay Area can be used sustainably.</em></p>

scholarly journals Cod catches taken by the German recreational fishery in the western Baltic Sea, 2005–2010: implications for stock assessment and management

2012 ◽  
Vol 69 (10) ◽  
pp. 1769-1780 ◽  
Author(s):  
Harry V. Strehlow ◽  
Norbert Schultz ◽  
Christopher Zimmermann ◽  
Cornelius Hammer
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
Stock Assessment ◽  
Mail Survey ◽  
Fishing Effort ◽  
Commercial Fishery ◽  
Catch Per Unit Effort ◽  
Yearly Variation ◽  
Fish Stocks ◽  
Recreational Fishery

Abstract Strehlow, H. V., Schultz, N., Zimmermann, C., and Hammer, C. 2012. Cod catches taken by the German recreational fishery in the western Baltic Sea, 2005–2010: implications for stock assessment and management. – ICES Journal of Marine Science, 69: 1769–1780. Next to the commercial fishery, the recreational fishery plays an important role in the removal of biomass from fish stocks. In this study, we present estimates of German recreational cod (Gadus morhua) catches in the western Baltic Sea between 2005 and 2010. Fishing effort was estimated using a stratified mail survey and annual sales of fishing licences. Catch per unit effort was estimated by stratified random sampling of access points and interviews about completed trips. Length distributions of cod catches were acquired by sampling recreational cod catches from charter boats and data from community fishing events. Estimates of the total cod biomass removed by the recreational fishery fluctuated between 2159 t in 2009 and 4127 t in 2005. Annual recreational fishery cod harvests accounted for a significant share of the total landings, with a yearly variation from 34 to 70% of the German commercial cod landings from the western Baltic Sea. The majority of recreational fishery cod catches were taken from private boats and charter vessels. Because of the amount and specifically the variability of the recreational catches, they are important for the assessment and management of the resource and, therefore, need to be surveyed annually.

scholarly journals Length-Based Stock Assessment of Smith's Barb, Puntioplites proctozystron (Bleeker, 1865) (Cyprinidae) and Asian Redtail Catfish, Hemibagrus nemurus, (Valenciennes, 1840), (Bagridae) in a Multipurpose Reservoir in Thailand

2021 ◽  
Vol 34 (2) ◽  
Author(s):  
KAJITPAN CHARERNNATE ◽  
PAVAROT NORANARTTRAGOON ◽  
TUANTONG JUTAGATE ◽  
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Relative Yield ◽  
Mesh Size ◽  
Fish Stock ◽  
Fish Stocks ◽  
The Status ◽  
Curvature Parameter ◽  
Spawning Potential Ratio ◽  
Fish Stock Assessment

Catches from inland fisheries in Thailand are about 200,000 tonnes annually and plays an important role in food security and subsidiary income. However, fish stocks are seldom assessed because of the lack of catch and effort data. In this study, two fish stock assessment models, viz., relative yield per recruit and length-based spawning potential ratio, were used to evaluate the status of two species as well as to highlight their applications to datalimited situation in Thailand. The study was conducted at Kangkrajan Reservoir, Thailand, for two targeted species, viz., Smith's barb, Puntioplites proctozystron (Bleeker, 1865) and Asian redtail catfish, Hemibagrus nemurus (Valenciennes, 1840) using length frequency data. The data were collected throughout 2019. Both species showed isometric growth. Von Bertalanffy growth parameters were estimated. Asymptotic length, curvature parameter and theoretical age at length zero were 36.2 cm TL, 0.39 yr-1 and -0.28 yr for P. proctozystron, respectively, and 63.2 cm TL, 0.37 yr-1 and -0.32 yr for H. nemurus. The exploitation rates reveal that both species are slightly overfished. Sizes at 50 % maturity and 50 % selectivities were 17.8 and 23.5 cm TL for P. proctozystron, respectively, and 15.6 and 20.8 cm TL for H. nemurus. Considering both parameters, the size at first capture to sustain the fisheries of P. proctozystron and H. nemurus should be >18 cm and >30 cm, respectively, which can be achieved by mesh-size regulations.

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