scholarly journals Growth and exploitation parameters of Ilisha africana, by-catch of the experimental fishing for the study on selectivity of gill nets for Ethmalosa fimbriata, in the Saloum estuary and Joal (Senegal)

2017 ◽  
Vol 8 (2) ◽  
pp. 14-22
Author(s):  
A. Faye ◽  
M. Diouf ◽  
A. Sarr ◽  
W. Ndiaye ◽  
A. Mbodj ◽  
...  
Keyword(s):  
Gill Nets ◽  
By Catch

Shark control: experimental fishing with baited drumlines

1998 ◽  
Vol 49 (7) ◽  
pp. 653 ◽  
Author(s):  
S. F. J. Dudley ◽  
R. C. Haestier ◽  
K. R. Cox ◽  
M. Murray
Keyword(s):  
Optimal Solution ◽  
Control Programme ◽  
Shark Species ◽  
Gill Nets ◽  
Carcharhinus Leucas ◽  
Local Reduction ◽  
Shark Attacks ◽  
By Catch ◽  
Catch Rates ◽  
Physical Environmental Factors

Protective gill-nets (shark nets) have been successful in reducing the frequency of shark attacks on the coast of KwaZulu-Natal (KZN), South Africa, since 1952. This is achieved primarily through a local reduction in numbers of large sharks. Yet the nets are non-selective in terms of shark species caught and take a by-catch of dolphins, sea turtles, batoids and teleosts. Baited lines, or drumlines, as used in the Queensland shark control programme, were tested as possible alternatives to gill-nets. They demonstrated greater species selectivity for sharks and also a reduced by-catch of non-shark animals. The shark catch included the three species responsible for most shark attacks on the KZN coast, Carcharhinus leucas, Galeocerdo cuvier and Carcharodon carcharias. The probability of the bait being scavenged, or a shark being caught, was modelled in relation to a number of physical environmental factors. Although there was insufficient variability in the effort data for a quantitative comparison of catch rates between nets and drumlines, the results suggested that an optimal solution may be to deploy a combination of nets and drumlines.

scholarly journals ANALISIS HASIL TANGKAPAN RAJUNGAN (PORTUNUS PELAGICUS) SEBAGAI TARGET UTAMA DAN KOMPOSISI BY-CATCH ALAT TANGKAP GILLNET DI PERAIRAN PANTAI PURIRANO, SULAWESI TENGGARA

2019 ◽  
Vol 19 (2) ◽  
pp. 205
Author(s):  
Normayanti Thamrin Mardhan ◽  
La Sara ◽  
Asriyana Asriyana
Keyword(s):  
Small Scale ◽  
Fishing Gear ◽  
Swimming Crab ◽  
Target Species ◽  
Portunus Pelagicus ◽  
Gill Nets ◽  
Male Crab ◽  
The Family ◽  
Main Target ◽  
By Catch

Abstrak : Penangkapan rajungan di perairan Pantai Purirano umumnya dilakukan oleh usaha perikanan rajungan skala kecil, yang menggunakan jaring insang (gillnet). Gillnet merupakan alat tangkap pasif yang pengoperasiannya tidak merusak sumberdaya hayati perairan. Walaupun demikian, gillnet merupakan alat tangkap yang tingkat selektivitasnya rendah, sehingga dikhawatirkan hasil tangkapan sampingan (bycatch) lebih banyak daripada hasil tangkapan utama (target species). Penelitian ini bertujuan untuk mengetahui proporsi hasil tangkapan rajungan (portunus pelagicus) sebagai target utama dan komposisi bycatch alat tangkap gillnet di perairan Pantai Purirano.Sampel rajungan ditangkap menggunakan jaring insang (gillnet) dengan ukuran mata jaring 4 inci & lebar jaring 80 cm. Hasil tangkapan selama penelitian diperoleh 29 jenis dari 25 famili. Hasil tangkapan yang diutamakan adalah rajungan dari famili Portunidae, tetapi terdapat juga jenis-jenis lain yang juga tertangkap (bycatch), yang sebagian dimanfaatkan (useable) dan sebagian lain dibuang ke laut (discarded). Jumlah total hasil tangkapan rajungan jantan selama penelitian adalah 58 ekor (54%) dan betina sebanyak 50 ekor (46%). Indeks dominansi hasil tangkapan tergolong rendah yaitu berkisar 0,21 – 0,27. Hal ini mengindikasikan bahwa selektivitas alat tangkap jaring insang tergolong rendah.Kata Kunci : Rajungan (Portunus pelagicus), Bycatch, Gillnet, PuriranoAbstrack : Catching crabs in Purirano Beach is generally carried out by small-scale crab fishing businesses, which use gillnet.  Gillnet is a passive fishing gear whose operation does not damage aquatic biological resources.  However, gillnet is a fishing tool with a low selectivity level, so it is feared that bycatch by-catch is more than the main catch (target species).  This study aims to determine the proportion of crab catches (portunus pelagicus) as the main target and the composition of gillnet fishing gear bycatch in Purirano Beach waters.  Swimming crab samples were captured using gill nets with mesh sizes of 4 inches & net width of 80 cm.  The catch during the study obtained 29 species from 25 families.  The preferred catch is crabs from the family Portunidae, but there are also other species that are also caught (bycatch), some are used (useable) and some others are thrown into the sea (discarded).  The total number of male crab catches during the study was 58 individuals (54%) and 50 females (46%).  The catch index dominance is relatively low, in the range of 0.21 - 0.27.  This indicates that the selectivity of gill nets is relatively low.Keywords : Rajungan (Portunus pelagicus), Bycatch, Gillnet, Purirano

The endangered Australian sea lion extensively overlaps with and regularly becomes by-catch in demersal shark gill-nets in South Australian shelf waters

2013 ◽  
Vol 157 ◽  
pp. 386-400 ◽  
Author(s):  
D.J. Hamer ◽  
S.D. Goldsworthy ◽  
D.P. Costa ◽  
S.L. Fowler ◽  
B. Page ◽  
...  
Keyword(s):  
Sea Lion ◽  
Gill Nets ◽  
Australian Sea Lion ◽  
By Catch

Modification of gill nets to minimize by-catch of sturgeons

2006 ◽  
Vol 22 (s1) ◽  
pp. 166-171 ◽  
Author(s):  
J. Gessner ◽  
G.-M. Arndt
Keyword(s):  
Gill Nets ◽  
By Catch

Covering up the by-catch problem

Nature ◽  
2017 ◽  
Vol 550 (7676) ◽  
pp. 304-304
Keyword(s):  
By Catch

Survival of by-catch from a beam trawl

1995 ◽  
Vol 126 ◽  
pp. 31-38 ◽  
Author(s):  
MJ Kaiser ◽  
BE Spencer
Keyword(s):  
Beam Trawl ◽  
By Catch

The Cost of Fishing on Juveniles of Finfish and Shellfish: Assessment of Economic Impacts of Trawl Juvenile by-Catch along the Coast of North Andhra Pradesh, India

2021 ◽  
Vol 37 (1) ◽  
pp. 409-426
Author(s):  
Pralaya Ranjan Behera ◽  
Shubhadeep Ghosh ◽  
K. Sree Ramulu ◽  
Muktha Menon ◽  
M. A. Jishnudev ◽  
...  
Keyword(s):  
Andhra Pradesh ◽  
Economic Impacts ◽  
By Catch ◽  
The Cost

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.

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