Understanding changes to fish stock abundance and associated conflicts: Perceptions of small-scale fishers from the Amazon coast of Brazil

2019 ◽  
Vol 182 ◽  
pp. 104954 ◽  
Author(s):  
Érica Antunes Jimenez ◽  
Roberta Sá Leitão Barboza ◽  
Marilu Teixeira Amaral ◽  
Flávia Lucena Frédou
Keyword(s):  
Fish Stock ◽  
Small Scale ◽  
Stock Abundance

scholarly journals Characterization of small-scale fisheries in the Camamu-Almada basin, southeast state of Bahia, Brazil

2008 ◽  
Vol 68 (4) ◽  
pp. 711-719 ◽  
Author(s):  
TCM. Souza ◽  
M. Petrere-Jr
Keyword(s):  
Low Income ◽  
Small Scale ◽  
Income Generation ◽  
Target Species ◽  
Market Prices ◽  
Marine Fishery ◽  
Small Scale Fisheries ◽  
Main Factor ◽  
Stock Abundance

In the Camamu-Almada basin, marine fishery is exclusively small-scale, with several structural deficiencies such as boats with low or absent navigational technology, lack of credit and low income. Local fishers complain that shrimp and lobster trawling fishing is the main factor responsible for low stock abundance, but they still persist in these activities as these two species command the highest market prices. So they feel that the target species are already over-fished. We suggest that proper management action, alternative ways of income generation and the payment of job insurance would help to mitigate the problem.

scholarly journals KEPADATAN STOK IKAN DEMERSAL DAN UDANG DI SAMUDERA HINDIA BARAT SUMATERA PADA MUSIM PERALIHAN II

2017 ◽  
Vol 22 (3) ◽  
pp. 139
Author(s):  
Nurulludin Nurulludin ◽  
Thomas Hidayat ◽  
Asep Mamun
Keyword(s):  
Indian Ocean ◽  
Demersal Fish ◽  
Catch Rate ◽  
Fish Stock ◽  
Fish Resources ◽  
The Indian Ocean ◽  
Density And Biomass ◽  
Swept Area ◽  
Average Catch ◽  
Stock Abundance

Kepadatan stok ikan merupakan indikasi dari potensi perikanan di suatu wilayah yang sangat penting diketahui. Tujuan tulisan ini membahas tentang laju tangkap, kepadatan stok dan perkiraan biomassa ikan demersal serta udang. Penelitian sumber daya ikan demersal dan udang di Samudera Hindia Barat Sumatera dilakukan dengan menggunakan Kapal Riset Baruna Jaya IV (1.200 GT) pada bulan Oktober dan November 2015 (Musim peralihan II). Penghitungan kepadatan stok menggunakan metode sweept area dengan panjang tali ris atas dari jaring trawl 36 m, kecepatan kapal saat menarik jaring berkisar 2,5 – 3 knot, lama penarikan jaring maksimal 1 jam. Perairan Samudera Hindia Barat Sumatera terdiri dari 151 spesies yang tergolong dalam 59 famili. Famili ikan demersal yang dominan tertangkap (5 besar), yaitu Leiognathidae sebesar 23,6 %, Trichiuridae 9,8%, Haemulidae 8,0%,  Engraulididae 6,6%, dan Polynemidae 6,05%. Famili udang yaitu Penaeidae (79,08%), Scyllaridae 19,49%, dan Solenoceridae 1,43%. Rata-rata laju tangkap ikan demersal 205,80 kg/jam, dengan kepadatan stok 6,66 ton/km2 dan udang 2,30 kg/jam dengan kepadatan stok 0,053 ton/km2. Biomassa ikan demersal diperkirakan sebesar 470.122 ton dan udang 3.706 ton.  Fish stock density  is an index of stock abundance indicating the fish resources potential in a region.  This paper discusses the catch rate, stock density and biomass estimates of the demersal fish and shrimp resources. Research on the demersal fish and shrimp resources in the Indian Ocean-Western Sumatera conducted using the Research Vessel Baruna Jaya IV (1200 GT) carried out during  October and November 2015 (2nd intermonsoon season). Stock density was estimated through the swept area method. The trawl used has 36 m headrope, trawling speed of 2.5 - 3 knots, and maximum towing time was 1 hour. It was found that the fish resources in the waters of the Indian Ocean-Western Sumatera consisted of 151 species belonging to 59 families. The top five dominant fish families caught were Leiognathidae of 23.6%, Trichiuridae 9.8%, Haemulidae 8.0%, Engraulididae 6.6%, and Polynemidae 6.05%, while the shrimp families were Penaeidae of 79.08%, Scyllaridae 19.49%, and Solenoceridae 1.43%. The average catch rate of demersal fish was 205.80 kg/hour, with a stock density of 6.66 tons/km2 and shrimp of 2.30 kg/hour with a stock density of 5.3 kgs/km2. The estimated biomass of demersal fish was  470,122 tons and shrimp was 3,706 tons.  

Behavioral Response to Stock Abundance in Exploiting Common-Pool Resources

2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Junjie Zhang
Keyword(s):  
Data Model ◽  
Traditional Method ◽  
Common Pool Resources ◽  
Stock Index ◽  
Fish Stock ◽  
Fishing Mortality ◽  
Resource Exploitation ◽  
Common Pool ◽  
Trip Frequency ◽  
Stock Abundance

Abstract Successful regulation of common-pool resources calls for a better understanding of resource exploitation behavior. This paper introduces an approach that can measure fishermen's responsiveness to stock changes more accurately. In order to deal with the challenge of the latent fish stock, I adopt the method proposed by Zhang and Smith (2011) that derives a stock index from a heterogeneous production function. I use the imputed stock proxy in a count data model that describes fishing trip frequency. By these two steps, I can estimate the stock elasticity of fishing mortality. In the empirical study of the reef-fish fishery in the northeastern Gulf of Mexico, I find that the popular method that uses catch rate as a stock proxy significantly underestimates fishermen's responses to stock changes. This result suggests that policy predictions based on the traditional method are overly optimistic.

scholarly journals KAJIAN PENANGGULANGAN IUUF PADA PERIKANAN CANTRANG DI LAUT JAWA (WPP – 712)

2014 ◽  
Vol 6 (2) ◽  
pp. 55
Author(s):  
Duto Nugroho ◽  
Suherman Banon Atmaja
Keyword(s):  
Fishery Management ◽  
Demersal Fish ◽  
Reference Points ◽  
Fish Stock ◽  
Small Scale ◽  
Fish Resources ◽  
Iuu Fishing ◽  
Data Collecting ◽  
Java Sea ◽  
Collecting System

<p>Kajian terhadap perikanan cantrang yang beroperasi di Laut Jawa dengan menggunakan perangkat pengelolaan cenderung dikategorikan sebagai perikanan akses terbuka. Penambahan armada secara historis memperlihatkan rendahnya pertimbangan terhadap pentingnya kelestarian sumber daya ikan, bebas beroperasi dan dalam banyak kasus tidak dikelola sesuai tatalaksana perikanan secara bertanggung jawab. Hasil penelitian menunjukkan sebagian besar armada cantrang dengan izin daerah melakukan penangkapan di luar batas 12 mil laut dan beroperasi di kawasan yang berdasarkan ketentuan diperuntukan bagi nelayan skala kecil yang bukan merupakan wewenang pemberi ijin armada cantrang dari panyai Utara Jawa. Studi kasus dilakukan di Pelabuhan Perikanan Tegal, ditujukan untuk menggambarkan sistem pendataan aktivitas penangkapan yang sedang berjalan. Hal ini berkaitan dengan sistem pencatatan data dan informasi perikanan setempat memiliki kemampuan dan kapasitas terbatas terutama pada sistem pemantauan, pengendalian dan pengawasan untuk melaksanakan pengelolaan perikanan berdasarkan prinsip tata laksana pemanfaatan secara berkelanjutan sesuai peraturan dan keputusan teknis. Terbatasnya pemahaman tentang dampak praktek perikanan tidak berkelanjutan, baik pada tingkat pelaku dan pembuat kebijakan merupakan permasalahan yang harus segera dipecahkan. Kajian ini menyimpulkan bahwa sistem yang berjalan hanya mampu merekam data kurang dari sepertiganya dan penerapan perikanan secara bertanggung jawab pada perikanan cantrang memberikan indikasi pada tingkat yang mengkhawatirkan terutama berdasarkan pertimbangan biologi, eksploitasi dan kelestarian lingkungan, serta memiliki potensi terjadinya unreported yang mengarah pada praktek IUU fishing. Temuan ini diharapkan dapat memperkuat tersedianya landasan pengelolaan perikanan terkait pemulihan sumberdaya ikan demersal bagi kepentingan pengembangan perikanan dalam jangka panjang di Laut Jawa.</p><p> </p><p>Study on demersal danish seine fishery operating in the Java Sea tend to be categorized as an open access fishery. The historical fleet development indicate no limited access to exploit demersal fish resources, which is in many cases the fishery are not well managed in a responsible manner. Study indicates that most of license to fish of demersal danish seine operate in areas outside 12 nm, somehow fleets operated in the area for small-scale fishers in the nearby coastal area beyond the origin of license authority. The objective is to describe the existing data collecting system. This corresponds to the limitation of capacity of the catch in one of fishing port. The data collecting system of local fisheries services has a limited capacity, particularly in monitoring, control and surveillance to implement best practices of fisheries management that declared through several technical reference points. Increasing awareness by complying with management measures of business sectors and policy makers must be immediately resolved. This study indicates current system covered less than a third of its landing data and it would affect the implementation of responsible fisheries based on bio-exploitation and environmental sustainability indicators on demersal fishery. It also has a potential on unreported that lead to IUU fishing practices. This should considered that bias of data could affect the accuracy of regular fish stock assessment. This finding should be treated to strengthen the long-term demersal danish seine fishery management plan as a baseline of sustainable demersal fish resources in the Java Sea.</p>

Effects of changes in stock productivity and mixing on sustainable fishing and economic viability

2016 ◽  
Vol 74 (2) ◽  
pp. 535-551 ◽  
Author(s):  
François Bastardie ◽  
J. Rasmus Nielsen ◽  
Margit Eero ◽  
Federico Fuga ◽  
Anna Rindorf
Keyword(s):  
Cumulative Effect ◽  
Size Composition ◽  
Reference Points ◽  
Economic Viability ◽  
Fish Stock ◽  
Spawning Stock ◽  
Cod Fisheries ◽  
Stock Mixing ◽  
Baltic Cod ◽  
Stock Abundance

Within the new FMSY European paradigm, this paper shows how a combination of changes in fish stock mixing, non-stationarity in productivity, and constraints on unit stock concepts undermine the effective management of fisheries, especially when management reference points are not adjusted accordingly. Recent changes in stock structures, conditions and stock mixing between eastern and western Baltic cod can jeopardize the reliability of stock assessments and of the fishery economy. We modelled how different management, individual vessel decision-making, and stock growth and mixing scenarios have induced alternative individual vessel spatial effort allocation and economic performance by affecting fishing costs and by changing the relative stock abundance and size distribution. Stock mixing heavily influences profit and stock abundance for stocks that have experienced increased fishing mortality (F) levels. Western cod F has increased from a higher total allowed catches (TAC) advised in the medium-term due to the westward migration of eastern cod while eastern cod F has increased from reduced growth in the east. Greater pressures on western cod and decreased eastern cod growth and conditions greatly reduce the overall cod spawning stock biomass, thus changing the landing size composition and associated fishery profits. As a cumulative effect, fishing efforts are redirected towards western areas depending on management (quotas). However, total profits are less affected when traditional fishing opportunities and switching possibilities for other species and areas are maintained. Our evaluation indicates that current management mechanisms cannot correct for potential detrimental effects on cod fisheries when effort re-allocation changes landing origins. By investigating different economic starting conditions we further show that Baltic cod mis-management could have resulted in unintended unequal (skewed) impacts and serious consequences for certain fleets and fishing communities compared with others. Our management strategy evaluation is instrumental in capturing non-linear effects of different recommendations on sustainability and economic viability, and we show that fixed F-values management is likely not an attainable or sufficient goal in ensuring the sustainability and viability of fisheries and stocks given changing biological conditions.

scholarly journals Drivers and barriers to sustainable fisheries in two peri-urban impoundments in Zimbabwe

Water SA ◽  
2019 ◽  
Vol 45 (4 October) ◽  
Author(s):  
Beaven Utete ◽  
Crispen Phiri ◽  
Tosan B Fregene
Keyword(s):  
Fish Stock ◽  
Small Scale ◽  
Community Based ◽  
Social Constructs ◽  
Small Scale Fisheries ◽  
Fisheries Sustainability ◽  
Community Fisheries ◽  
Operational Frameworks ◽  
Water Quality And Quantity ◽  
Quantitative And Qualitative Methods

Fisheries sustainability is categorised through four conceptual pillars: ecological, economic, and social, including cultural and institutional. Much work on fisheries sustainability has been done in marine fisheries relative to inland fisheries. Two inland peri-urban impoundments, Chivero and Manyame in Zimbabwe, support numerous small-scale fisheries; however, environmental and socioeconomic variables threaten the sustainability of the fisheries. This study aimed to identify and contextualise drivers and barriers to sustainability of small-scale fisheries in these two peri-urban impoundments. We applied three frameworks, Fishery Performance Indicators, Community-Based Fishery Indicators and FAO Small-Scale Fisheries Indicators, to identify and contextualise the drivers and barriers. Quantitative and qualitative methods were used to collect data from fishers in the two impoundments. A structured questionnaire was administered to 115 fishers in 23 fishing companies operating in the two lakes. Fisheries income and revenue as well as food security are key drivers. Lack of post-harvest equipment, volatile fish markets, water quality and quantity deterioration and fish stock decreases are key barriers to sustainability of fisheries in the two impoundments. There are subtle differences in the extent and impact of the drivers and barriers of fisheries sustainability in the two lakes. The differences relate to the uniqueness of the aquatic habitats, social constructs and fisheries operational frameworks in each lake. This suggests a need to assess fisheries sustainability using an integrated bottom-up approach starting from individual fisheries < community fisheries < global/generic fisheries.

Catchability and the spatial distribution of fishing vessels

2003 ◽  
Vol 60 (3) ◽  
pp. 259-268 ◽  
Author(s):  
Are Salthaug ◽  
Sondre Aanes
Keyword(s):  
Gadus Morhua ◽  
Fish Stock ◽  
Melanogrammus Aeglefinus ◽  
Catch Per Unit Effort ◽  
Spatial Concentration ◽  
Commercial Catch ◽  
Fish Stocks ◽  
Fishing Vessels ◽  
The Relationship ◽  
Stock Abundance

A central problem when using commercial catch per unit effort (CPUE) as an index of fish stock abundance is that fishing vessels search for concentrations of fish. For a given stock abundance, CPUE may become high if the vessels succeed in finding patches of fish and low if the vessels distribute their catching operations more randomly. In this work, the relationship between catchability and two measures of the degree of spatial concentration of a trawl fleet (the fleet's spatial extent and the fleet's degree of spatial patchiness) is investigated for four different fish stocks. The catchability of northeast Arctic cod (Gadus morhua) is strongly related to the fleet's degree of spatial concentration, but the relationship is weaker for northeast Arctic haddock (Melanogrammus aeglefinus), and no relationships appear for two saithe (Pollachius virens) stocks. Our findings suggest that adjusting CPUE with a measure of the fleet's average degree of concentration relates CPUE more strongly with abundance for migratory stocks.

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