scholarly journals ANGKA ACUAN SASARAN UNTUK PENGELOLAAN PERIKANAN UDANG LAUT ARAFURA DENGAN TUJUAN BERAGAM

2013 ◽  
Vol 5 (2) ◽  
pp. 73
Author(s):  
Purwanto Purwanto
Keyword(s):  
Fisheries Management ◽  
Programming Model ◽  
National Development ◽  
Fishing Effort ◽  
Optimal Number ◽  
Reference Points ◽  
Shrimp Fishery ◽  
Fishing Vessels ◽  
Conflicting Objectives ◽  
Arafura Sea

<p>Kriteria pengelolaan perikanan dalam kerangka pembangunan nasional, yaitu pro-growth, pro-poor, pro-job dan pro-environment, mengarahkan pengelolaan perikanan udang di Laut Arafura untuk mengoptimumkan produksi lestari dan keuntungan perikanan, serta meningkatkan keuntungan per kapal dan peluang kerja sebagai nelayan. Masing-masing tujuan tersebut perlu ditetapkan angka acuan sasarannya yang diharapkan dicapai dalam pengelolaan perikanan. Mengingat tujuan tersebut saling bertentangan, sehingga tidak dapat dicapai bersamaan, perlu ditentukan tingkat kompromi optimal diantara tujuan tersebut dan angka acuan sasarannya. Tulisan ini menyajikan model pemrograman matematika untuk optimisasi dengan empat tujuan pengelolaan, serta menggunakannya untuk mengestimasi angka acuan sasaran dan jumlah optimal kapal penangkap. Hasil optimisasi dengan pemberian bobot prioritas yang sama terhadap empat tujuan pengelolaan perikanan dalam kerangka pembangunan nasional menunjukkan bahwa angka acuan sasaran pada tingkat kompromi optimal dicapai dengan pengendalian upaya penangkapan pada tingkat yang setara dengan daya tangkap 512 kapal pukat udang 130 GT. Angka acuan sasaran yang sama dihasilkan dari optimisasi dengan pemberian bobot prioritas yang lebih tinggi terhadap dua tujuan pengelolaan perikanan sesuai dengan Pasal 6 Undang Undang Perikanan tahun 2004.</p><p>The criteria of fisheries management undertaken in a framework of national development, particularly pro-growth, pro-poor, pro-job and pro-environment, guide the management of shrimp fishery in the Arafura Sea to optimising shrimp production and fishery profit, and increasing per vessel profit and job opportunity as fishers. As those objectives were conflicting that could not be achieved simultaneously, it is necessary to seek an optimal compromise amongst several conflicting objectives and to estimate their target reference points. This paper presents a mathematical programming model accommodating four objectives of fisheries management, and the utilisation of this for estimating the target reference points and the optimal number of fishing vessels. The result of optimisation shows that target reference points at the optimal compromise levels for the four conflicting objectives, with equal priority, of fisheries management supporting the national development could be achieved by controlling fishing effort at the level equal to fishing power of 512 shrimp trawlers of 130 GT. The same target reference points resulted from the analysis providing higher priority to the objectives of fisheries management stated in Article 6 of Fisheries Act of 2004.</p>

scholarly journals MODEL OPTIMISASI DENGAN SASARAN BERAGAM UNTUK PENGELOLAAN PERIKANAN UDANG DI LAUT ARAFURA

2017 ◽  
Vol 3 (1) ◽  
pp. 61
Author(s):  
Purwanto Purwanto
Keyword(s):  
Fishery Management ◽  
Programming Model ◽  
National Development ◽  
Fishing Effort ◽  
Optimal Number ◽  
Shrimp Fishery ◽  
Fishing Vessels ◽  
Conflicting Objectives ◽  
Shrimp Production ◽  
Arafura Sea

Kriteria pengelolaan perikanan dalam kerangka pembangunan nasional, yaitu pro-growth, pro-poor, pro-job, dan pro-environment, mengarahkan pengelolaan perikanan udang di Laut Arafura untuk mencapai kelangsungan produktivitas stok udang, mengoptimumkan produksi dan total keuntungan perikanan, serta meningkatkan keuntungan pelaku usaha dan peluang kerja di kapal perikanan. Sementara itu, visi dan misi Kementerian Kelautan dan Perikanan memberikan prioritas yang lebih tinggi kepada optimisasi produksi dan total keuntungan perikanan. Tujuan-tujuan pengelolaan perikanan tersebut saling bertentangan sehingga tidak dapat dicapai secara bersamaan. Oleh karena itu perlu ditentukan tingkat kompromi optimal di antara tujuan-tujuan tersebut dan sasarannya. Tulisan ini menyajikan model pemrograman matematika untuk optimisasi dengan tujuan beragam yang mengakomodasikan empat sasaran pengelolaan perikanan serta menggunakannya untuk mengestimasi tingkat kompromi optimal dari empat sasaran tersebut dan jumlah optimal kapal penangkap udang. Hasil analisis dengan memberikan bobot prioritas yang sama terhadap empat tujuan pengelolaan perikanan dalam kerangka pembangunan nasional menunjukkan bahwa tingkat kompromi optimal dicapai dengan pengendalian upaya penangkapan pada tingkat yang setara dengan 511 kapal pukat udang berukuran 130 GT. Tingkat kompromi optimal yang sama dihasilkan dari analisis dengan memberikan bobot prioritas yang lebih tinggi terhadap dua tujuan pengelolaan perikanan untuk mendukung upaya pencapaian visi dan misi Kementerian Kelautan dan Perikanan. Hal ini mengindikasikan bahwa strategi pengelolaan perikanan guna mendukung pencapaian visi dan misi Kementerian Kelautan dan Perikanan tidak berbeda dari strategi pengelolaan perikanan dalam kerangka pembangunan nasional.The criteria of fisheries management undertaken in a framework of national development, particularly pro-growth, pro-poor, pro-job, and pro-environment, guide the management of shrimp fishery in the Arafura Sea to achieving sustainable shrimp stock productivity, optimising shrimp production and total fishery profit, and increasing average fisher profit and job opportunity as vessel crews. Meanwhile, the vision and the mission of the Ministry of Marine Affairs and Fisheries provided higher priorities to optimising shrimp production and total profit of fishery. However, those objectives were conflicting that couldnot be achieved simultaneously. Therefore, it is necessary to seek an optimal compromise amongst several conflicting objectives or to achieve satisficing levels of goals. This paper presents a mathematical programming model accommodating four goals of fishery management, and the utilisation of this for estimating the optimal compromise solution to the goals and the optimal number of fishing vessels. The result of analysis shows that the optimal compromise levels for the four conflicting objectives of fishery management supporting the national development could be achieved by controlling fishing effort at the level equal to 511 shrimp trawlers of 130 GT. The same optimal compromise levels resulted from the analysis providing higher priority to the objectives to achieve the vision and the mission of the Ministry of Marine Affairs and Fisheries. This indicates that the fishery management strategy to achieve the vision and the mission of the Ministry of Marine Affairs and Fisheries was not different from the strategy to support the national development.

scholarly journals COMPROMISE SOLUTION TO THE CONFLICTING OBJECTIVES IN THE MANAGEMENT OF THE ARAFURA SEA SHRIMP FISHERY

2017 ◽  
Vol 17 (1) ◽  
pp. 37
Author(s):  
Purwanto Purwanto
Keyword(s):  
Economic Losses ◽  
Compromise Solution ◽  
Shrimp Fishery ◽  
Illegal Fishing ◽  
Fishing Vessels ◽  
Conflicting Objectives ◽  
Arafura Sea ◽  
Over Exploitation ◽  
Fishing Practices

Fisheries mis-management, including over allocation of fishing vessels, and illegal fishing practices in the Arafura Sea shrimp fishery had resulted in over exploitation of shrimp stock and economic losses.

scholarly journals Fisheries for the future: greenhouse gas emission consequences of different fishery reference points

2020 ◽  
Vol 77 (5) ◽  
pp. 1666-1671
Author(s):  
Sara Hornborg ◽  
Anthony D M Smith
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Greenhouse Gas Emission ◽  
Fuel Efficiency ◽  
Fishing Effort ◽  
Reference Points ◽  
Production Model ◽  
Fuel Use ◽  
Gas Emissions ◽  
Fishing Vessels

Abstract Global fisheries have for long been scrutinized in terms of ecosystem effects but only more recently for their greenhouse gas emissions. These emissions are dominated by fuel use on fishing vessels and the levels are often neglected side effects of resource overexploitation. Using a simple production model, Pella-Tomlinson, we illustrate how fuel efficiency (fuel use per unit of catch) varies with the level of exploitation and biomass depletion. For this model, fuel use per unit catch rises hyperbolically with fishing effort—it is relatively flat at low levels of effort but rises steeply as effort increases and biomass and catch decline. In light of these findings, the general fuel efficiency relationship with common fishery reference points on stock status is discussed, as well as other means of reducing fuel use and thus greenhouse gas emissions. We conclude that much may be gained by considering fuel efficiency in setting reference points for target stock biomass in fisheries and encourage further investigations.

scholarly journals Immediate maximum economic yield; a realistic fisheries economic reference point

2009 ◽  
Vol 67 (3) ◽  
pp. 577-582 ◽  
Author(s):  
Jordi Lleonart ◽  
Gorka Merino
Keyword(s):  
Reference Point ◽  
Fishing Effort ◽  
Reference Points ◽  
Economic Rent ◽  
Short Term ◽  
Fishing Season ◽  
Shrimp Fishery ◽  
Maximum Economic Yield ◽  
Nw Mediterranean ◽  
Definition Of

Abstract Lleonart, J., and Merino, G. 2010. Immediate maximum economic yield; a realistic fisheries economic reference point. – ICES Journal of Marine Science, 67: 577–582. Unregulated or poorly managed fisheries tend towards overexploitation, but fisheries rent does not completely dissipate when immediate rent maximization is sought. The principle of immediate economic rent maximization is the basis of the derivation of a classic model and has led to the definition of a relationship in a catch-and-effort diagram termed the dynamic immediate maximum economic yield (DIMEY) curve. For any initial biomass, if the economic rent in the immediate fishing season is maximized, then the fishing effort and catch strategy that follows will be located on the DIMEY curve. The DIMEY curve is not only used for dynamic simulation but also used to identify a new reference point, the immediate maximum economic yield (IMEY), which is proposed as more realistic than the classic open-access solution for unregulated fisheries. IMEY is proposed as an asymptotic outcome for unregulated or poorly managed fisheries when short-term economic objectives drive fleet activities. IMEY properties are described and compared with traditional fisheries reference points in the yield-and-effort diagram. Theoretical conclusions are compared with empirical evidence provided by the red shrimp fishery off Blanes, Spain (NW Mediterranean). Observed catch-and-effort records are plotted and were positively correlated with the DIMEY curve and IMEY.

Setting biological reference points for sea scallops (Placopecten magellanicus) allowing for the spatial distribution of productivity and fishing effort

2017 ◽  
Vol 74 (5) ◽  
pp. 650-667 ◽  
Author(s):  
Stephen J. Smith ◽  
Jessica A. Sameoto ◽  
Craig J. Brown
Keyword(s):  
Spatial Distribution ◽  
Habitat Suitability ◽  
Spatial Model ◽  
Stock Assessment ◽  
Fishing Effort ◽  
Reference Points ◽  
Assessment Model ◽  
Fishing Mortality ◽  
Placopecten Magellanicus ◽  
Fishing Vessels

Management for the major sea scallop (Placopecten magellanicus) fisheries in Canada is based on maximum sustainable yield (MSY) biomass and fishing mortality reference points applied to the whole stock, under the assumption that fishing mortality is uniformly distributed in space. However, scallop fishing vessels concentrate fishing in areas that consistently exhibit high densities resulting in a nonuniform spatial distribution of fishing effort. This study applies a spatial model for fishing effort derived from satellite vessel monitoring system data, scallop habitat suitability maps, and relative scallop density from a spatial stock assessment model to evaluate precautionary approach reference points in support of sustainable management. Target harvest rates were evaluated in terms of MSY for the higher habitat suitability areas. The results indicated that although MSY for the spatial model were similar to those when assuming a uniform distribution of effort, the biomass and catch rates over all areas were higher. The spatial model predicted that the MSY would be taken with less fishing effort, potentially lessening the benthic impacts from the scallop fishery.

scholarly journals THE BIOLOGICAL OPTIMAL LEVEL OF THE ARAFURA SHRIMP FISHERY

2017 ◽  
Vol 16 (2) ◽  
pp. 79 ◽  
Author(s):  
Purwanto Purwanto
Keyword(s):  
Optimal Level ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Paper Briefly ◽  
Shrimp Fishery ◽  
Illegal Fishing ◽  
The Past ◽  
Arafura Sea ◽  
The Impact

This paper briefly describes the past development of the shrimp fishery in the Arafura Sea, including intensity of illegal fishing, and presents the impact of increasing fishing pressure on the quantity of catch and biomass. The maximum sustainable yield and the optimum fishing effort are estimated.

scholarly journals Diversification insulates fisher catch and revenue in heavily exploited tropical fisheries

2020 ◽  
Vol 6 (8) ◽  
pp. eaaz0587 ◽  
Author(s):  
James P. W. Robinson ◽  
Jan Robinson ◽  
Calvin Gerry ◽  
Rodney Govinden ◽  
Cameron Freshwater ◽  
...  
Keyword(s):  
High Resolution ◽  
Fisheries Management ◽  
Management Strategies ◽  
Fishing Effort ◽  
Marine Resources ◽  
Nutritional Security ◽  
Fishing Vessels ◽  
Species Groups ◽  
Catch Rates ◽  
Average Catch

Declines in commercial landings and increases in fishing fleet power have raised concerns over the continued provisioning of nutritional and economic services by tropical wild fisheries. Yet, because tropical fisheries are often data-poor, mechanisms that might buffer fishers to declines are not understood. This data scarcity undermines fisheries management, making tropical fishing livelihoods particularly vulnerable to changes in marine resources. We use high-resolution fisheries data from Seychelles to understand how fishing strategy (catch diversification) influences catch rates and revenues of individual fishing vessels. We show that average catch weight decreased by 65% over 27 years, with declines in all nine species groups coinciding with increases in fishing effort. However, for individual vessels, catch diversity was associated with larger catches and higher fishing revenues and with slower catch declines from 1990 to 2016. Management strategies should maximize catch diversity in data-poor tropical fisheries to help secure nutritional security while protecting fishing livelihoods.

scholarly journals LIMIT REFERENCE POINTS OF FISHING PARAMETERS IN LAKES AND RESERVOIRS OF KAZAKHSTAN

2021 ◽  
Vol 2021 (2) ◽  
pp. 41-46
Author(s):  
Evgeniy Vyacheslavovich Kulikov ◽  
Saule Zhangirovna Assylbekova ◽  
Kuanysh Baibulatovich Isbekov
Keyword(s):  
Fishing Effort ◽  
Reference Points ◽  
Water Bodies ◽  
Commercial Fishing ◽  
Fishing Gear ◽  
Control Mechanisms ◽  
Fish Stocks ◽  
Fishing Vessels ◽  
Lakes And Reservoirs ◽  
The Republic

The article deals with the problems of regulating commercial fishing in the water bodies of Kazakhstan. Analysis of data on fishing in large reservoirs of the Republic of Kazakhstan shows that along with natural changes in the fish stocks (when the water level in the reservoir decreases), the fishing intensity makes the greatest impact on the state of fish stocks. Today a pre-existing limiter as the fishing regime (the number of fishing gear and fishermen) completely has fallen out of the fishing control mechanisms. According to some reports, the catch of fish with fishing gear available to fishermen, increases the established limits by 1.5–2 times. Thus, the possible catch significantly exceeds the registered (official) catch. It is proposed to use the regulation of the fishing regime (the number of fishing gear, fishing vessels, fishermen) as a measure that determines the limits of safe effort and to limit unrecorded fishing on water bodies. The number of fishermen in the pond should not only meet the criteria for safe effort, but also allow fishing organizations to conduct profitable fishing. The calculation of the maximum allowable number of fishing performance indicators (limit reference points of fishing effort) are given.

Optimal number of sites in artificial pelagic multisite fisheries

2010 ◽  
Vol 67 (2) ◽  
pp. 296-303 ◽  
Author(s):  
Pierre Auger ◽  
Christophe Lett ◽  
Ali Moussaoui ◽  
Sylvain Pioch
Keyword(s):  
Linear Chain ◽  
Fishing Effort ◽  
Optimal Number ◽  
Fish Stock ◽  
Total Catch ◽  
Fleet Size ◽  
Fishing Vessels ◽  
Total Fish ◽  
Fish Aggregating Devices ◽  
Global Activity

We present a mathematical model of artificial pelagic multisite fisheries. The model is a stock–effort dynamical model of a fishery subdivided into artificial fishing sites such as fish-aggregating devices (FADs) or artificial habitats (AHs). The objective of the work is to investigate the effects of the number of sites on the global activity of the fishery. We consider a linear chain of fishing sites in which fish are harvested by fishing vessels and a free stock that is unattached to the sites and not exploited. Fish movements between the sites and the free stock, as well as vessel displacements between the sites, are assumed to take place at a faster time scale than the variation of the stock and the change of the fleet size. We take advantage of these two time scales to derive a reduced model governing the dynamics of the total fish stock and the total fishing effort. We show that there exists an optimal number of fishing sites that maximizes the total catch at equilibrium. We finally extend the model to the situation in which both fish attached to the sites and fish in the free stock are exploited.

Using length data to derive biological reference points for kiddi shrimp Parapenaeopsis stylifera (Milne Edwards, 1837) from the south-eastern Arabian Sea, India

2021 ◽  
Vol 34 ◽  
pp. 8
Author(s):  
Saraswathy Lakshmi Pillai ◽  
Gidda Maheswarudu ◽  
Ponnathara Kandankoran Baby ◽  
Madavan Radhakrishnan ◽  
Nadakkal Ragesh ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Cohort Analysis ◽  
Relative Yield ◽  
Penaeid Shrimp ◽  
Reference Points ◽  
Parameter Estimates ◽  
Fishery Resource ◽  
Shrimp Fishery ◽  
Length Data ◽  
Yield Per Recruit

Parapenaeopsis stylifera, a major commercial penaeid shrimp fishery resource in the Indian Ocean, has lacked adequate information on life history parameters for nearly two decades. In this study, growth and mortality parameters of P. stylifera from the southwest coast of India were estimated using length data and used to derive biological reference points for the species. The asymptotic length for females was L∞ = 131 mm; k = 1.1 y−1 and for males L∞ = 117 mm; k = 1.25 y−1. Mortality parameter estimates were Z = 4.42, M = 1.24, F = 3.18 y−1 and exploitation rate E = 0.72 for females; Z = 5.76, M = 1.39, F = 4.37 y−1 and E = 0.76 for males. Thomson and Bell yield biomass, Beverton and Holt yield per recruit, and relative yield per recruit models were applied to predict the stock status and length cohort analysis for estimating the stock size. The Beverton and Holt analysis gave Emax = 0.69 in females and 0.75 for males, which is below the Ecurrent values obtained for the sexes. The Thomson and Bell analysis indicated that if Fcurrent at which the yield is 121 460 t in females and in males 128 064 t is further increased, rise in yield will be modest. B/B0 and SB/SB0 at Fcurrent were 24% and 18% for females and 21% and 16% for males, respectively. Target reference point F0.1 and F0.5 at different levels of age at capture tc (0.5, 0.6, 0.7 and 0.8 yrs) was estimated by Beverton and Holt yield per recruit model. The outcome from these models forms integral inputs for multispecies/multigear tropical fisheries management. Parapenaeopsis stylifera is one of the inshore penaeid shrimp identified by the Marine Stewardship Council for certification from the region and, moreover, biological reference points are a prerequisite to assessment and management of tropical multispecies fisheries for ecosystem-based fisheries management.

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