scholarly journals A long term (1949-2010) study of catch and effort in Israeli trawl fishery, Eastern Mediterranean Sea

2017 ◽  
Vol 58 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Daniel Golani ◽  
Dor Edelist ◽  
Amit Lerner ◽  
Oren Sonin ◽  
Uzi Motro

The trawl fishery of the Mediterranean coast of Israel was analyzed vis á vis catch and fishing effort for the years 1949-2010. The Maximum Sustainable Yield (MSY) was calculated using the Fox surplus-yield model and was found to be 1,413 ton per annum using 1,415 units of effort (fishing days X engine power divided by 1000). Only during nine years (1997-2005) did fishing effort exceed the value for which the yield is the MSY by an average of 184.9 units of effort, but the yield was similar to that of the previous years. During 10 years the catch exceeded the MSY by an average of 153±119 tons. This result was used to justify the “freezing” of the local trawl fleet at the beginning of the 1990’s.

2020 ◽  
Vol 67 (1) ◽  
Author(s):  
T. V. Sathianandan ◽  
Somy Kuriakose ◽  
K. G. Mini ◽  
P. K. Safeena

The south-west region of the Indian coast is shared by three maritime states and it contributes nearly 32% to the total marine fish production of the country. Mechanised trawl fishery accounts for 44% of the marine fish harvest in the south-west coast and a number of resources are harvested by trawl nets from this region. An assessment of the trawl fishery to determine sustainable harvest levels for mechanised trawlers in the region was carried out using time series data on annual landings and fishing effort of mechanised trawlers during the period 1990-2015. A Bayesian estimation method for Schaefer model was used for the analysis. Posterior probability densities of parameters of the model, maximum sustainable yield (MSY) and corresponding biomass were obtained through Bayesian estimation for the trawl fishery in south-west coast and the harvest levels were found to be above MSY from 2012 onwards. Forecasts of biomass and fish landings by mechanised trawlers upto 2025 under different levels of fishing effort were also simulated using the model to study the dynamic changes over time. It was found that the numbers of multiday trawlers and single day trawlers operating in this region have to be reduced by 207 and 36 respectively to retain the harvest at sustainable level.


2018 ◽  
Vol 76 (2) ◽  
pp. 402-409
Author(s):  
Irini Tsikopoulou ◽  
Chris J Smith ◽  
Nadia K Papadopoulou ◽  
Elena Eleftheriadou ◽  
Ioannis Karakassis

AbstractFisheries have global socioeconomic and ecological effects. Long-term ecological studies could be beneficial to ecosystem approach management and biodiversity conservation, however, they are rare. In this study, the impacts of bottom trawling on a traditional fishing ground in the Eastern Mediterranean were addressed and an improvement in diversity metrics and ecological quality status were detected and ascribed to the Greek economic crisis. After 18 years, there was a modest increase in species richness, total abundance, and ecological status in the unaffected zone and more pronounced improvement in the trawled zone pointing at a possible link to a decrease in fishing effort. This upturn emphasized the strong link between financial activities and ecology. The present study underlines the multiple and variable effects of economy not only on countries and citizens but also on the environment and ecosystem conservation and management.


2019 ◽  
Vol 10 (1) ◽  
pp. 18
Author(s):  
Donald H. Simanjuntak ◽  
Lawrence J. L. Lumingas ◽  
Joudy R. R. Sangari

This research was conducted in the city of Bitung, North Sulawesi Province with activities centered on the Bitung Ocean Fisheries Port (PPS), which began from mid March to April 2019. The fishing activities studied are using the fishing areas around the waters of  North Sulawesi Province namely the Sulawesi Sea and The Maluku Sea which are included in WPP 715 and 716 based on tuna catch landed data on PPS Bitung. The purpose of this study was to analyze the value of sustainable potential by looking at the level of utilization and Maximum Sustainable Yield (MSY) of tuna in the waters around North Sulawesi Province based on a surplus production model approach (Schaefer Model). This research is expected to be used as a consideration in the management of tuna stocks around the waters of North Sulawesi Province, and can be used as a basis for further research. This study uses a secondary data collection method in the form of fishery statistics documents. The data used are data from tuna fishing and fishing (effort), from 2014 to 2018 (5 years). The results showed that the sustainable potential of tuna fisheries around the waters of North Sulawesi Province based on North Sulawesi PPS data indicated that, the sustainable potential value of tuna that could be caught was 14,173.51 tons / year which is counted as 80% of the value of tuna resources around the waters of North Sulawesi Province. PPS Bitung data which amounted to 17,716.15 tons / year for Hmsy, 1,200.15 trips / year for Emsy, with an average CPUE value of 2014-2018 of 19 tons / trip. The level of tuna utilization around the waters of North Sulawesi Province is based on data from PPS Bitung in 2014, 2017 and 2018 which indicate that there were indications of overfishing with the largest utilization rate in 2014 which reached a value of 155.09%.Keywords: tuna, Bitung, Bitung PPS, sustainable potential, MSY. ABSTRAKKegiatan penelitian ini berlangsung di Kota Bitung, Provinsi Sulawesi Utara dengan kegiatan berpusat di Pelabuhan Perikanan Samudera (PPS) Bitung, yang dimulai  dari pertengahan bulan Maret hingga bulan April 2019. Aktivitas perikanan tangkap yang ditelaah berlangsung di sekitar perairan Provinsi Sulawesi Utara yaitu Laut Sulawesi dan Laut Maluku yang masuk ke dalam WPP 715 dan 716 berdasarkan data tangkapan tuna yang didaratkan di PPS Bitung. Tujuan dari penelitian ini adalah untuk menganalisis nilai potensi lestari dengan melihat tingkat pemanfaatan dan maximum sustainable yield (MSY) ikan tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan pendekatan model produksi surplus (Model Schaefer). Penelitan ini diharapkan dapat digunakan sebagai bahan pertimbangan dalam pengelolaan stok ikan tuna di sekitar perairan Provinsi Sulawesi Utara, serta dapat digunakan sebagai dasar untuk penelitian selanjutnya.  Penelitian ini menggunakan metode pengumpulan data sekunder berbentuk dokumen. Data yang diambil adalah data tangkapan ikan tuna dan upaya penangkapan ikan atau effort (trip), dari tahun 2014 sampai dengan 2018 (5 Tahun). Hasil penelitian menunjukkan potensi lestari perikanan tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan data PPS Bitung Sulawesi Utara nilai potensi lestari tuna yang bisa ditangkap adalah 14.173,51 ton/tahun 80% dari nilai pemanfaatan sumber daya perikanan tangkap tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan data PPS Bitung yang sebesar 17.716,15 ton/tahun untuk Hmsy, 1.200,15 trip/tahun untuk Emsy, dengan nilai CPUE rata-rata tahun 2014-2018 sebesar 19 ton/trip. Tingkat pemanfaatan tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan data PPS Bitung Sulawesi Utara di tahun 2014,2017 dan 2018 sudah yang menandakan adanya indikasi overfishing dengan tingkat pemanfaatan terbesar di tahun 2014 yang mencapai nilai 155,09%.Kata Kunci: ikan tuna, Bitung, PPS Bitung, potensi lestari, MSY.


2020 ◽  
Vol 42 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Dor Edelist ◽  
Tamar Guy-Haim ◽  
Zafrir Kuplik ◽  
Noa Zuckerman ◽  
Philip Nemoy ◽  
...  

Abstract Jellyfish (JF) swarms impact human wellbeing and marine ecosystems. Their global proliferation is a matter of concern and scientific debate, and the multitude of factors affecting (and affected by) their density and distribution merits long-term monitoring of their populations. Here we present an eight-year time series for Rhopilema nomadica, the most prominent JF species swarming the Eastern Mediterranean Sea. Reports were submitted by the public and within it a group of trained participants via an internet website between June 2011 and June 2019. Data collected included species, size, location, ranked amount and stinging. Swarms of R. nomadica prevailed in July and ended in August but were also prominent in winter from January to March. Both observations deviate from past swarming patterns described in the late 1980s, when summer swarms persevered until October and winter swarms were not documented. Climate change (increasing water temperature) and the westwards up-current spread of R. nomadica are discussed as possible explanations for this phenological shift. We further demonstrate how data obtained by Citizen Science is used to develop a swarming indicator and monitor JF in time and space, and propose a forecast based on these observations.


Crustacea ◽  
2020 ◽  
Author(s):  
Jorge Homero Rodriguez Castro ◽  
Sandra Edith Olmeda de la Fuente ◽  
Wanda Ortiz Baez ◽  
Alfonso Correa Sandoval ◽  
Jose Alberto Ramirez de León

Author(s):  
Maizan Sharfina ◽  
Mennofatria Boer ◽  
Yunizar Ernawati

<p>ABSTRACT<br />Yellowstripe scad included the one of commodity that has an important economic value in the Sunda Strait. Commonly, this species processed by Pandeglang fishermen to be the boiled fish, salted fish, grilled fish, besides it also traded in fresh or frozen fish product. The high market demand can not offset the production of this species from the nature. Therefore, it needed an information about resources of yellowstripe scad in the waters of the Sunda Strait in order to manage it well. The objective of this study was to estimate the maximum sustainable yield (MSY) and the optimum fishing effort (fopt), so that the yellowstripe scad resources in the waters of the Sunda Strait can be utilized optimally and sustainably. Based on the standardization analysis, the purse seine be made the standard fishing gear for estimating the MSY of yellowstripe scad. The yellowstripe scad growth patterns during the study is isometric. Trends of CPUE of the yellowstripe scad fisheries tends to decrease during 2003 to 2013. Then, this species was estimated its maximum sustainable yield (MSY) of 304.50 tons per year, with the optimum fishing effort of 12.478 trips per year. The decline of the catch per fishing effort can indicated that the yellowstripe scad fishing conditions in the Sunda Strait was having the overfishing phenomenon.</p><p><br />Key words: Sunda Strait, sustainable potential, yellowstripe scad</p><p>-------</p><p>ABSTRAK</p><p><br />Ikan selar kuning termasuk salah satu komoditas perikanan yang memiliki nilai ekonomis penting di perairan Selat Sunda. Jenis ikan ini, selain banyak dimanfaatkan oleh nelayan sekitar Kabupaten Pandeglang sebagai ikan pindang, ikan bakar, ikan asin, juga diperdagangkan dalam keadaan segar maupun dibekukan. Tingginya permintaan pasar tidak dapat mengimbangi produksi ikan tersebut di alam. Oleh karena itu, untuk memperoleh informasi mengenai tingkat pemanfaatan sumber daya ikan selar kuning di perairan Selat Sunda, diperlukan suatu kajian mengenai potensi lestari ikan selar kuning. Tujuan dari penelitian ini adalah untuk mengetahui hasil tangkapan maksimum lestari (maximum sustainable yield atau MSY) serta upaya penangkapan maksimum lestari (fopt) sehingga sumberdaya ikan selar kuning di Perairan Selat Sunda dapat dimanfaatkan secara optimal dan berkelanjutan. Berdasarkan hasil standardisasi, alat tangkap standart yang digunakan adalah purse seine. Pola pertumbuhan ikan selar kuning selama penelitian, yaitu isometrik. Hasil perhitungan CPUE menunjukkan adanya produksi yang cenderung menurun dengan upaya penangkapan yang meningkat dari tahun 2003 sampai 2013. Hasil perhitungan potensi hasil tangkapan maksimum lestari (MSY) diestimasi sebesar 304,50 ton per tahun, dan upaya penangkapan optimumnya adalah 12.478 trip per tahun. Penurunan hasil tangkapan per upaya penangkapan dapat dijadikan salah satu indikasi bahwa kondisi penangkapan ikan selar kuning di Perairan Selat Sunda sedang mengalami gejala lebih tangkap atau overfishing.</p><p><br />Kata kunci: Selat Sunda, potensi lestari, ikan selar kuning</p>


2017 ◽  
Vol 8 (2) ◽  
pp. 713-728
Author(s):  
Yulia Estmirar Tanjov ◽  
Roza Yusfiandayani ◽  
. Mustaruddin

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.


2017 ◽  
Vol 8 (2) ◽  
pp. 713
Author(s):  
Yulia Estmirar Tanjov ◽  
Roza Yusfiandayani ◽  
. Mustaruddin

<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>


Science ◽  
2019 ◽  
Vol 363 (6430) ◽  
pp. 979-983 ◽  
Author(s):  
Christopher M. Free ◽  
James T. Thorson ◽  
Malin L. Pinsky ◽  
Kiva L. Oken ◽  
John Wiedenmann ◽  
...  

Climate change is altering habitats for marine fishes and invertebrates, but the net effect of these changes on potential food production is unknown. We used temperature-dependent population models to measure the influence of warming on the productivity of 235 populations of 124 species in 38 ecoregions. Some populations responded significantly positively (n = 9 populations) and others responded significantly negatively (n = 19 populations) to warming, with the direction and magnitude of the response explained by ecoregion, taxonomy, life history, and exploitation history. Hindcasts indicate that the maximum sustainable yield of the evaluated populations decreased by 4.1% from 1930 to 2010, with five ecoregions experiencing losses of 15 to 35%. Outcomes of fisheries management—including long-term food provisioning—will be improved by accounting for changing productivity in a warmer ocean.


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