scholarly journals Utility of morphological data for key fish species in southeastern Australian beach‐seine and otter‐trawl fisheries: Predicting mesh size and configuration

2006 ◽  
Vol 40 (2) ◽  
pp. 259-272 ◽  
Author(s):  
Matt K. Broadhurst ◽  
Koenraad K. P. Dijkstra ◽  
Dennis D. Reid ◽  
Charles A. Gray
Keyword(s):  
Fish Species ◽  
Mesh Size ◽  
Morphological Data ◽  
Otter Trawl ◽  
Beach Seine ◽  
Trawl Fisheries

scholarly journals Effect of Cutting Ratio and Catch on Drag Characteristics and Fluttering Motions of Midwater Trawl Codend

2021 ◽  
Vol 9 (3) ◽  
pp. 256
Author(s):  
Wei Liu ◽  
Hao Tang ◽  
Xinxing You ◽  
Shuchuang Dong ◽  
Liuxiong Xu ◽  
...  
Keyword(s):  
Drag Force ◽  
Mesh Size ◽  
Current Speed ◽  
Midwater Trawl ◽  
Minimum Drag ◽  
Fish Catch ◽  
Spatial Geometry ◽  
By Catch ◽  
Trawl Fisheries ◽  
Crucial Part

The codend of a trawl net is the rearmost and crucial part of the net for selective fish catch and juvenile escape. To ensure efficient and sustainable midwater trawl fisheries, it is essential to better understand the drag characteristics and fluttering motions of a midwater trawl codend. These are generally affected by catch, cutting ratio, mesh size, and twine diameter. In this study, six nylon codend models with different cutting ratios (no cutting, 6:1, 5:1, 4:1, 7:2, and 3:1) were designed and tested in a professional flume tank under two conditions (empty codends and codends with catch) and five current speeds to obtain the drag force, spatial geometry, and movement trend. As the cutting ratio of empty codends decreased, the drag force decreased, and the drag coefficient increased. The unfolding degree of codend netting and the height of empty codends were found to be directly proportional to the current speed and inversely proportional to the cutting ratio. The positional amplitude of codend with cutting ratio 4:1 was the smallest for catch. The drag force of codends with catch increased as the current speed increased, and first decreased and then increased as the cutting ratio decreased. To ensure the best stability and minimum drag force of the codend, it is recommended to use the 4:1 cutting ratio codend.

Size Changes, Mortality, and Equilibrium Yields in an Exploited Stock of American Plaice (Hippoglossoides platessoides)

1969 ◽  
Vol 26 (5) ◽  
pp. 1205-1235 ◽  
Author(s):  
P. M. Powles
Keyword(s):  
Mesh Size ◽  
Food Competition ◽  
Mortality Factor ◽  
Otter Trawl ◽  
Small Fish ◽  
Large Fish ◽  
Age Composition ◽  
Instantaneous Rate ◽  
Factors Affecting ◽  
Ecological Dominance

Records from research surveys and commercial landings for American plaice from the Magdalen Shallows, or the southwestern Gulf of St. Lawrence, showed decreases in percentage of old, large fish and in catch per unit of effort from 1955 to 1962. The changes in age composition were clearly relatable to the fishery, which was mainly by otter trawl. Ricker models indicated that wastage of deck-exposed subcommercial plaice is currently a greater mortality factor than predation by cod. Increased landings in particular years were associated with successful year-classes. Other factors affecting landings were annual differences in fleet dispersal, which were related to movements of cod, a cohabiting species. No clear decrease or increase in absolute recruitment of plaice was demonstratable because quantitative comparisons of research surveys by different vessels using different gears and with different skippers, would be misleading.Mortality estimates of adult plaice by three methods showed agreement, indicating that instantaneous rate of natural mortality was between 0.09 and 0.13. The instantaneous rate of fishing for 1957–62 was 0.46. Increasing mesh-size would reduce cod catches and have little effect in conserving plaice, but marketing small fish would increase plaice landings. Voluntary release of small plaice promptly on capture would help maintain the stock, as would reduction in numbers of large cod, the main predator of small plaice. Increased numbers of small cod since 1959, as reported by other workers, could result in greater food competition with small plaice, effectively reinforcing the ecological dominance of cod over plaice.

The size selectivity of whiting (Merlangius merlangus euxinus) caught by gillnet in the eastern Black Sea of Turkey

2014 ◽  
Vol 94 (7) ◽  
pp. 1539-1544
Author(s):  
Ferhat Kalaycı ◽  
Tuncay Yeşılçıçek
Keyword(s):  
Black Sea ◽  
Fish Species ◽  
Sexual Maturity ◽  
Mesh Size ◽  
Size Selectivity ◽  
Selectivity Curve ◽  
Merlangius Merlangus

The size selectivity of traditional gillnets for whiting, (Merlangius merlangus euxinus) was investigated in the eastern Black Sea between June 2010 and June 2011. Experimental fishing operations were carried out by using gillnets of 16, 17, 18, 20 and 22 mm mesh size. A total of 2038 specimens belonging to 16 different fish species were caught during the experiment. The Share Each Length's Catch Total method was used to fit gillnet selectivity curves. Gillnet selectivity was best described by a bi-modal selectivity curve. The modal catch sizes were estimated as 14.81, 15.74, 16.66, 18.51 and 20.37 cm for 16, 17, 18, 20 and 22 mm mesh sizes, respectively. Modal lengths and spread values increased with increasing mesh size. The majority of fish (71.8%) caught by 16 mm mesh size were less than the length at first sexual maturity.

scholarly journals Somatic growth and age of selected commercial fish species of the Cullera Coast, Iberian Peninsula, south-east Spain

2019 ◽  
Vol 66 (3) ◽  
Author(s):  
Angela Maria Jaramillo-Londono ◽  
Alejandra Vanina Volpedo ◽  
Jose Luis Diaz-Arevalo ◽  
Maria Eugenia Rodrigo-Santamalia ◽  
Vicent Bendito-Dura
Keyword(s):  
Fish Species ◽  
Somatic Growth ◽  
Mesh Size ◽  
Age And Growth ◽  
Biological Information ◽  
Growth Equation ◽  
Commercial Fish ◽  
Mullus Surmuletus ◽  
Von Bertalanffy Growth Equation ◽  
Uranoscopus Scaber

This work provides data on the somatic growth and age of selected commercial fish species of the Cullera Coast, Spain. The biological information available that permits responsible fishing management of these species is relatively scarce. This study was conducted in the Bay of Cullera, Spain (39º 12’to 38º 59’N, and 0º 09’to 0º 15’W); and selected benthic fish species were analysed that are frequently fished by trammel nets (mesh size 28-76 mm) at a maximum depth of 30 m. Maturity , age and growth of 63 torpedoes, Torpedo torpedo (L., 1758), 115 red scorpionfish, Scorpaena scrofa Linnaeus, 1758, 280 red mullets, Mullus surmuletus Linnaeus, 1758, 139 stargazers, Uranoscopus scaber Linnaeus, 1758, and 476 Portuguese soles, Dagetichthys lusitanicus de Brito Capello, 1868 were analysed. The data obtained in this study revealed that 50% of individuals of all the species reached sexual maturity at a TL (total length) of 20.0-36.5 cm and at an age of 2-6 years. The von Bertalanffy growth equation derived were: TL=37.0 (1 - e(-0.2(t + 0.33))); TL =31.5(1 - e(-0.38(t + 0.54))); TL =35.5(1 - e(-0.2(t + 2.08))); and TL =34.3(1 - e(-0.14(t + 2.16))) for S. scrofa, M. surmuletus; U. scaber and D. lusitanicus respectively.

scholarly journals First Assessment of the Thryssa vitrirostris (Engraulidae) Beach Seine Fishery in Northeastern Mozambique

J ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 116-132
Author(s):  
Bonifácio Manuessa ◽  
Eurico Morais ◽  
Teresa Cerveira Borges ◽  
Maria Teodósio ◽  
Francisco Leitão
Keyword(s):  
Standard Length ◽  
Growth Parameters ◽  
Mesh Size ◽  
Fishing Effort ◽  
Fishing Mortality ◽  
Beach Seine ◽  
Management Measures ◽  
Exploitation Rate ◽  
Exploitation Status ◽  
Sustainable Fishery

Monthly length-frequency data, from 2009 to 2014, was used to estimate the growth parameters, mortality, and spawning season, and to assess the exploitation status of Thryssa vitrirostris (Engraulidae) fisheries in Pebane. The von Bertalanffy asymptotic length (L∞) and growth rate (K) were 25.1 cm (standard length) and 0.41 per year (standard length), respectively. Two proxy recruitment peaks were found: the first peak of recruitment occurs from April to July, and the second recruitment peak from September to October. The total estimated mortality rates (Z), natural mortality (M), and fishing mortality (F) were Z = 1.31, M = 0.92, and F = 0.39. For the beach seine gear, the size at first catch of T. vitrirostris was Lc25 = 4.43 cm. The 50% retention size of the catch was Lc50 = 5.39 cm. The retention probability analyses revealed a large rate of juvenile fishing mortality (54.2%). The estimated exploitation rate (0.30) was below the maximum exploitation rate (0.48), and above the optimal sustainable exploitation rate (E50 = 0.28), evidencing a sustainable fishery. However, under such an exploitation regime, it is advised that a continuously monitoring-survey of T. vitrirostris is maintained. An increase in migration of fishermen has been recently recorded in Pebane, due to its rich fisheries, which can increase the fishing effort and the risk of overexploitation if management measures (such as mesh size increase) are not taken in advance.

scholarly journals Catch assessment of artisanal marine fishing gears in Cox’s Bazar and Teknaf of Bangladesh

2016 ◽  
Vol 27 (2) ◽  
pp. 228-234
Author(s):  
SK Ghosh ◽  
MK Ahsan ◽  
MK Ahmmed ◽  
SI Ahmed ◽  
MM Hasan ◽  
...  
Keyword(s):  
Fish Species ◽  
Fishing Gear ◽  
Catch Per Unit Effort ◽  
Beach Seine ◽  
Gill Net ◽  
Fishing Gears ◽  
Dominant Fish ◽  
Commercially Important ◽  
Marine Fishing ◽  
Harpadon Nehereus

Studies were conducted on catch assessment of some artisanal marine fishing gears operated in Cox’s Bazar and Teknaf areas from April 2014 to April 2015. Sixteen types of fishing gears were identified, of which gill net, beach seine net, estuarine set bag net, marine set bag net and trammel net occupy major fishing activities. Although estuarine set bag net (ESBN) is a legally restricted fishing gear recorded the highest catch per unit effort (CPUE) (110 kg/gear/day) in July followed by marine set bag net (MSBN) (105 kg/gear/day) in Cox’s Bazar and the highest CPUE was recorded 100 kg/gear/day by ESBN in June followed by MSBN (90 kg/gear/day) in Teknaf. Out of 52 species of fishes, the major fish species abundantly caught by these gears were Poa (Otolithoides argenteus), Churi (Trichiurus haumela), Loittya (Harpadon nehereus), Ranga choukha (Lutjanus johni), Lal poa (Johnius argentatus), Olua (Coilia dussumieri), Rup chanda (Stromateus chinensis), (Stromateus argenteus) and Ilish (Tenualosa ilisha). Besides these fish species, 10 commercially important shrimp species and 3 important crab species were also recorded during the study period. The peak season of availability of most fish species was June and July while lean season was December and January. This study indicated that Otolithoides argenteus) was the dominant fish species followed by Trichiurus haumela, Harpadon nehereus and Coilia dussumieri.Progressive Agriculture 27 (2): 228-234, 2016

Otter-Trawl Fisheries of South Africa

1949 ◽  
Vol 39 (4) ◽  
pp. 529 ◽  
Author(s):  
Peter Scott
Keyword(s):  
South Africa ◽  
Otter Trawl ◽  
Trawl Fisheries

scholarly journals Kajian Kelimpahan Mikroplastik di Biota Perairan

2021 ◽  
Vol 19 (3) ◽  
pp. 638-648
Author(s):  
Saptian Wisnu Sandra ◽  
Arlini Dyah Radityaningrum
Keyword(s):  
Fish Species ◽  
Oreochromis Niloticus ◽  
Sea Water ◽  
Mesh Size ◽  
The Body ◽  
Aquatic Biota ◽  
Biological Processes ◽  
Whatman Filter Paper ◽  
Saccostrea Cucullata ◽  
Zeus Faber

Sampah plastik dapat terdegradasi menjadi mikroplastik (MP) dan nanoplastik (NP) melalui proses fisik, kimia, dan biologis. MP didefinisikan sebagai partikel plastik kecil berukuran < 5 mm. MP saat ini telah ditemukan di tubuh biota perairan, baik perairan permukaan maupun perairan laut. Tujuan penelitian ini adalah mengkaji MP pada biota perairan. Metode yang digunakan dalam penelitian ini adalah studi literatur terhadap artikel publikasi 10 tahun terakhir. Kajian dilakukan terhadap kelimpahan, ukuran, bentuk, warna, dan komposisi MP pada biota perairan permukaan dan laut. Review dilakukan terhadap penelitian di Indonesia dan berbagai wilayah di negara lain. Beberapa metode pengambilan sampel biota perairan yang digunakan dalam penelitian terdahulu yaitu menggunakan trawl atau pukat dasar (jaring polietilen), jaring pukat pantai (10 m x 1,5 m; ukuran mata jaring: 8 mm). Identifikasi MP pada saluran pencernakan biota ikan dilakukan menggunakan larutan KOH 10% selama 24 jam pada suhu 60°C, selanjutnya dilakukan penyaringan dengan kertas saring Whatman. Selanjutnya, proses identifikasi menggunakan mikroskop okuler dan FTIR untuk menentukan ukuran, bentuk, dan jenis polimer. Hasil kajian menunjukkan bahwa kelimpahan MP terbanyak pada biota perairan masing-masing yaitu 468 partikel MP/individu pada spesies Ikan Sapu-Sapu (Hypostomus plecostomus) di perairan sungai; 18 partikel MP/individu pada Ikan Nila Hitam (Oreochromis niloticus) di perairan payau; 1,4 – 7 partikel MP/individu pada spesies Tiram (Saccostrea cucullata) di perairan muara; 22,21 ± 1,7 partikel MP/individu pada spesies Ikan Thryssa kammalensis di perairan teluk; 2,7 ± 0,10 partikel MP/individu pada spesies Ikan Zeus faber di perairan selat; dan 22,3 partikel MP/individu pada Diadema sp. (Bulu babi) di perairan laut. MP yang dominan pada biota perairan adalah berukuran 20 μm – 50 μm, berbentuk fiber, dan berwarna hitam. Polyethylene (PE) ditemukan dominan pada biota perairan permukaan, serta polyprophylene (PP) dan polyethylene (PE) pada biota perairan laut.ABSTRACTPlastic wastes could be degraded into microplastic (MP) and nanoplastic (NP) through physical, chemical, and biological processes. MP was defined as the small particle of plastic with the size of < 5 mm. Currently, MP has been found in the body of aquatic biota both in the surface and sea water biota. This research aimed to investigate the microplastic content in aquatic biota. The study was conducted through literature review of the last 10 year published articles. The previous studies were reviewed in terms of abundance, size, shape, colour, and polymer type of MP in the aquatic biota in Indonesia and areas of other countries. Sampling of aquatic biota in the previous studies was conducted in several methods using trawling or bottom trawl (polyethylene net), beach trawl net (10 m x 1.5 m; mesh size: 8 mm). Identification of MP in the digestive tract of fish was conducted using 10% KOH solution for 24 hours at a temperature of 60°C, then was filtered using Whatman filter paper. Next, the identification process used an ocular microscope and FTIR to determine the polymer. The result demonstrated that the highest number of MP abundance was 468 MP particles/individual in the cattle fish (Hypostomus plecostomus) species in the river water; 18 MP particles/individual in the black nile fish (Oreochromis niloticus) species in the brackish water; 1.4 – 7 MP particles/individual in the oyster (Saccostrea cucullata) species in the estuary water; 22.21 ± 1.7 MP particles/individual in the Thryssa kammalensis fish species in the gulf water; 2.7 ± 0.10 MP particles/individual in the Zeus faber fish species in the strait water; and 22.3 MP particles/individual in the Diadema sp. (sea urchin) in the sea water. The most dominant MP size, shape, and colour in the aquatic biota was 20 μm – 50 μm, fiber, and black. Polyethylene (PE) was dominant in the surface water biota, whereas, polyprophylene (PP) and polyethylene (PE) in the sea water biota.

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