scholarly journals Catch and discardfish species of trawl fisheries in the Iskenderun Bay (Northeastern Mediterranean) with emphasis on lessepsian and chondricthyan species

2014 ◽  
Vol 15 (2) ◽  
pp. 380 ◽  
Author(s):  
E. YEMISKEN ◽  
C. DALYAN ◽  
L. ERYILMAZ

Fish species in catch and discard of trawl fisheries in and around Iskenderun Bay were examined within the fishing closure period and fishingperiod.The sampling was performed from May 2010 to January 2011 by a commercial trawl vessel.Chondricthyan species composed 49 % of discard catch biomass whileGymnura altavela and Dasyatis pastinacawere dominant in hauls. 27 lessepsian fish species were captured during the study,nine of them beingtarget species for trawl fisheries. In total, 14 of the lessepsian fish species were determined as discard species.In both sampling periods, Equulites klunzingeriand Citharus linguatula contributed to discard fish catch dissimilarity among depth ranges (deeper and shallower than 60 m). E. klunzingerishowed high abundance in discard catch.There were no significant differences in the distribution of the discard fish biomass between the sampling periods (ANOVA test, p>0.05). However, depth range pointed out significantdifferences in discard fish catch composition (p<0.05).Among major commercial fish species of trawl fisheries, Mullus surmuletus and Sparus aurata were not separated as discard in anyhaul by fishermen. Any size of these two species  were included in commercial catch (Total length ranged from 61 to 721 mm).

2017 ◽  
Vol 15 (2) ◽  
pp. 105
Author(s):  
Dharmadi Dharmadi ◽  
Endi Setiadi Kartamihardja ◽  
Agus Djoko Utomo ◽  
Dian Oktaviani

Tujuan penelitian ini adalah untuk mengetahui komposisi dan fluktuasi hasil tangkapan tuguk pada periode berbeda yang dioperasikan di Sungai Lempuing, Sumatera Selatan. Kegiatan penelitian dilaksanakan dengan metode survei pada periode musim peralihan penghujan sampai dengan kemarau (bulan April), musim kemarau (bulan Juni) dan musim penghujan (bulan Desember) tahun 2007. Komposisi jenis ikan dan hasil tangkapan diperoleh berdasarkan pada data pengambilan contoh pada saat ke lapangan dan data harian hasil tangkapan tuguk yang dicatat oleh 3 orang enumerator. Data dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa hasil tangkapan tuguk berbeda menurut periode waktu. Hasil tangkapan terdiri atas 11 jenis ikan untuk musim peralihan dan kemarau masing-masing berkisar 400-450 kg per unit per hari (rata-rata 411,2+14,1 kg per unit per hari) dan 250-300 kg per unit per hari (rata-rata 263,3+13,4 kg per unit per hari) dan 13 jenis ikan pada musim penghujan (bulan Desember) berkisar 700-750 kg per unit per hari (rata-rata 724,8+17,7 kg per unit per hari). Hasil tangkapan didominansi oleh jenis ikan lele (Clarias melanoderma) dan baung (Mystus nemurus). Selama penelitian, kandungan oksigen terlarut di perairan relatif rendah, berkisar 2-4 mg per l, namun dapat ditolelir oleh kelompok jenis ikan rawa (black fish). This research proposed to observed a catch composition and fluctuation of filtering device in different periods operated in the Lempuing River, South Sumatera. The research was conducted using survey method at a respective month of April (transition season), June (dry season) and December 07 (wet season). Fish composition and catch of tuguk were noted during survey and based on recording 3 enumerators. Descriptive analysis was used in this study. The results show that the catch of filtering device differed on diferent season periodes. A number of 11 fish species was caught at a respective season of transition season (April) of 400-450 kg per unit per day (average=411.2+14,1 kg per unit per day), dry season (June) of 250 300 kg per unit per day (average = 263,3+13,4 kg per unit per day), whilst at rainy season (December), fish catch composed of 13 fish species, ranging 700-750 kg per unit per day or (average = 724.8+17.7 kg per unit per day). Clarias melanoderma and Mystus nemurus were dominantly caught in the Lempuing River waters. During observation, dissolved oxygen content was relatively low (2-4 mg per l), that but could be tolerated by black fish.


2019 ◽  
Vol 66 (3) ◽  
Author(s):  
Angela Maria Jaramillo-Londono ◽  
Alejandra Vanina Volpedo ◽  
Jose Luis Diaz-Arevalo ◽  
Maria Eugenia Rodrigo-Santamalia ◽  
Vicent Bendito-Dura

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.


1982 ◽  
Vol 14 (9-11) ◽  
pp. 1185-1194 ◽  
Author(s):  
R B Clark

Pollution is defined as environmental contamination which has a deleterious effect, and in a biological context it is only mortality which has some impact at the level of the population or community that is important. Thus, very heavy mortality of the eggs and fry of commercial fish species may have no detectable effect on the commercial catch in future years. A reduction in the population of a species which is dominant in its community, on the other hand is likely to result in major ecological adjustment. Oil pollution does not appear to have reduced populations of commercial fish species or seabirds, the two groups of animals about which most fears have been expressed. The marine environment is subject to wide and erratic fluctuations which make it difficult to detect the impact of oil pollution unless the cause is obvious, even then some caution is necessary before attributing environmental change to pollution.


2020 ◽  
Vol 40 (1) ◽  
pp. 197-206
Author(s):  
D. O. Odulate ◽  
I. T. Omoniyi ◽  
Y. Akegbejo-Samsons

Fish is a major source of protein in human diets. Fish demand has been on the increase due to increase in human population which has resulted to wide gap between fish demand and supply. This study was carried out to elucidate the major fish species that are economically important in the study area. Assessment of fish catch composition was done in the marine artisanal fish sector of Southwest Nigeria Gulf of Guinea. The study area was divided into three strata with one sampling station selected from each stratum. Four canoes were sampled per site per month. Fish catches were sorted into taxonomic categories, counted, measured and weighed. Sixty-nine fish species from forty-two families were identified constituting fifty-nine finfish and ten shellfish species. Clupeid family had the highest contribution both by weight (40.5%) and abundance (53.7%). Sardinella maderensis was the most abundant species by number (30.6%) and weight (27.9%). Parapenaeopsis atlanticus (51%) was the most abundant shellfish while P. validus (87%) was the highest by weight. Fish production was highest in Station 1 both by weight (37%) and abundance (41%). The status of finfish species showed that five species were very common; four were common, fourteen uncommon and thirty-six rare. Among the shellfish species, three species were very common, none was common, three were uncommon and three species rare. Effective management of these fish resources is necessary to ensure fish food security.


2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Olaniyi Alaba Olopade ◽  
Nkuene Gbenekanu Sinclair ◽  
Henry Dienye

Fish catch composition of some selected small scale fishing gears (gill net, cast net, beach seine and long line) were investigated in Bonny River, Rivers State, Nigeria from August 2014 to January 2015. A total number of 25 fish species from 18 families were recorded during the study. The Mugilidae with only one species constituted the dominant family while Cichlidae, Lutjanidae, Clupeidae, had three species and Scianidae had two species of fish caught and the remaining families had one species each. Mugil cephalus constituted 28.48% of the total catches followed by C. nigrodigitatus (22.48%). In the dry season M. cephalus forms the major component landings (32.65%), followed by C. nigrodigitatus (26.53%) and S. galilaeus (12.24%) while in the wet season M. cephalus (31.06%), C. nigrodigitatus (18.63%) and T. zillii (11.80%) were the dominant fish species. Cast net was the most efficient fishing gear while gill net was the least efficient. The comparison analysis between the wet and dry seasons using t-test showed no significant difference between dry and wet seasons (t = 0.092, P > 0.05).


2010 ◽  
Vol 73 (3) ◽  
pp. 306-311 ◽  
Author(s):  
Judit Kalman ◽  
Inmaculada Riba ◽  
T. Ángel DelValls ◽  
Julián Blasco

Author(s):  
Vitaliy Victorovich Barabanov ◽  
Gennadij Grigor'evich Kolosyuk

Fisheries measures is an instrument allowing to regulate fish catch pressing to the aquatic bio-resources stocks. Roach and sheatfish are the species which are exploited in industrial and amateur fisheries of the Volga-Caspian basin (the Astrakhan region). According to the Fishery Regulations, today the minimum allowable length for roach is 17 centimeters, and for sheatfish it is 60 centimeters. According to the results of retrospective analysis of stocks dynamics, commercial catch of roach and cheatfish, experience in changing fisheries measures for roach and sheatfish in the Volga-Caspian basin, changing fisheries measures for these species has been found inexpedient. The current fisheries measures for commercial catch of roach allows to exploit only the reproductive part of the population, minimizing losses of restocking. Also, the work shows that a change of fisheries measures for sheatfish will lead to the decrease of the commercial catch of sheatfish and objects of its ration. In general, it must be stressed that changing fisheries measures will lead to redistribution of roach and sheatfish catches between the main participants (commercial fishers, amateur fishers and poachers), but not in favor of the official fish catching


Author(s):  
Edward Vladimirovich Nikitin

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.


2021 ◽  
Vol 9 (3) ◽  
pp. 256
Author(s):  
Wei Liu ◽  
Hao Tang ◽  
Xinxing You ◽  
Shuchuang Dong ◽  
Liuxiong Xu ◽  
...  

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.


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