Assessment of fishing gear and catch rate in Oguta Lake, south Eastern Nigeria

2018 ◽  
Vol 26 (1) ◽  
pp. 1-9
Author(s):  
G. Adaka ◽  
C. Ogueri ◽  
D. Nwaka ◽  
D. Njoku ◽  
A. Nlewadim

This study was carried out in Oguta Lake, Imo State, Nigeria, from January, 2012 to December, 2013 at five stations (Onu Utu, Okposha, Ogbe Hausa, Osemotor and Ede Ngwugwu) to ascertain the percentage abundance and catch rate of gear and craft. The average weight of fish caught per canoe per day ranged between 3.2 kg for Basket and Drum traps to 47.1 kg for boat seine net. The gill nets ranged between 6.0 to 13.0kg per canoe per day with mean weight of 8.60±2.91kg, the cast net had values ranging from 1.0 to 7.0 kg with a mean weight of 4.3±2.49 kg. Lift net yielded an average of 3.4 kg per canoe per day. Gill nets were the main gear used by fishers, followed by long lines and cast nets at the lake. It is important to locate all the fishers operating in the lake and daily record of catches be collected for a more accurate picture of the total catch and fish species. Mesh size regulation prevent over exploitation of young fish, before they attain sexual maturity. It is recommended that the cost of procuring fishing inputs such as fishing gear and crafts and safety kits should be monitored by government and be subsidized for the fishers.Key words: drum trap, crafts, catch, exploitation, Oguta, mesh size, trap

2021 ◽  
Vol 328 ◽  
pp. 08011
Author(s):  
Sajriawati Sajriawati

The purpose of this study was to determine the fishing technology used by fishermen in Merauke to catch snapper and post-harvest handling of fish maw snapper. This research was conducted in January 2021 in Kumbe Village, Malind District. Data collection was carried out by interviewing fishermen on the fishing boat KMN Nur Aqila07. The results showed that the fishing boat KMN Nur Aqila07 has a weight specification of 30 GT. The main fishing gear is a drift gill net with a length of 50 meters with a width of 2 meters with a mesh size of 7.5 inches. The pulley machine is used to help pull the gill nets when they want to pull fishing gear (hauling). Fish maw of snapper is removed manually using a knife, then cleaned with running water and then dried in the sun to dry. Fish maw is sold dry. The highest price for fish maw is in the weight range of 150 grams which can reach Rp. 22,500,000 per kg, while the lowest price is in the weight range of less than 50 grams, which is Rp. 4,500,000 per kg.


2017 ◽  
Vol 2 (2) ◽  
pp. 101
Author(s):  
Bambang Sumiono ◽  
Tri Ernawati ◽  
Wedjatmiko Wedjatmiko

Perairan di sekitar Barru Sulawesi Selatan merupakan salah satu kawasan terumbu karang yang penting di Selat Makassar. Sebagian besar dari nelayannya melakukan penangkapan ikan dengan menggunakan rawai dasar dan jaring insang dasar. Analisis perikanan ikan kakap merah (Lutjanus spp.) dan kerapu (Epinephelus sp.) dilakukan pada bulan Agustus dan Oktober 2006 dengan penekanan pada deskripsi alat tangkap dan teknik penangkapannya, komposisi hasil tangkapan, dan beberapa aspek biologi ikan kakap merah dan kerapu. Penelitian ini dilakukan dengan cara mengikuti kegiatan nelayan yang menggunakan rawai dasar dan jaring insang dasar di sekitar terumbu karang dan pencatatan data dari pendaratan ikan utama. Untuk kelengkapan data dilakukan wawancara dengan nelayan dan pedagang pengumpul setempat. Hasil penelitian ini menunjukan daerah penyebaran ikan kakap merah dan kerapu terdapat di perairan Barru dan Pangkajene Kepulauan. Pada perairan yang relatif dangkal (<50 m) digunakan pancing ulur dengan satu atau dua mata pancing (nomor 6 atau 7). Jaring insang dasar digunakan di luar daerah karang, satu pis (tinting) mempunyai panjang 40 m dan dalam 5 m dengan ukuran mata jaring 4 inci. Satu unit jaring terdiri atas 60 pis. Di perairan yang lebih dalam (lebih dari 50) digunakan rawai dasar yang terdiri atas 600 mata pancing (nomor 7 atau 8). Lama trip penangkapan tiga hari. Diperoleh laju pancing pada rawai dasar berkisar 6-8% dan laju tangkap jaring insang dasar berkisar antara 40-60 kg/kapal/tiga hari. Komposisi hasil tangkapan didominansi (47,2%) oleh ikan kakap merah (famili Lutjanidae) yang terdiri atas jenis Lutjanus malabaricus, Lutjanus hyselopterus, Lutjanus sebae, Lutjanus vittus, dan Pinjalo pinjalo. Ikan kerapu (famili Serranidae) terdiri atas jenis Epinephelus areolatus, Epinephelus malabaricus, Epinephelus microdon, dan Plectropomus maculatus. Kecuali itu tertangkap juga ikan lencam (famili Lethrinidae). Pengamatan biologi jenis ikan Lutjanus malabaricus dan Epinephelus malabaricus yang merupakan hasil tangkapan dominan masing-masing diperoleh nilai modus panjang cagak 48 dan 56 cm dengan modus bobot masing-masing 1,8 dan 2,15 kg. Karakteristik pertumbuhan kedua jenis tersebut adalah allometrik positif.The sea waters around Barru, South Sulawesi is one of the coral reef parts in Makassar Strait. Most of the fishermen use fishing lines, bottom long lines, and bottom gill nets in their fishing activities. Analysis of red snappers (Lutjanus spp.) and groupers (Epinephelus sp.) fisheries in this area were carried out in August and October, 2006. The emphasis is focused on the discription of fishing gear and fishing technique, catch composition, and some of biological aspect of red snappers and groupers. The research was done by following the fishing operations of bottom long line and bottom gill net conducted by fishers in the waters around coral reefs. Data were recorded in some importantant landing place at Barru, and interview of some fishermen to complete data and information needed. The result showed that the distribution of red snapper and groupers occured in the waters around Barru and Pangkajene Islands. In the shallow waters (<50 m) the fishermen use a lightly weighted hand line, with one or two relativelly small hooks (nomor 6 or 7). Bottom gill nets are frequently used in shallow back reef areas with one piece of 40 m in length, and 5 m in depth, with mesh size of 4 inches. One unit of the gear consisted of 60 piece of the nets. Meanwhile, in deeper waters (50-150 m), the number of hooks (nomor 7 or 8) in bottom long line operated 600 hooks for each unit. All fishing gears usually have three days at sea for a fishing trip. The average of catch rate (hook rate) for a trip of bottom long line was 6-8% (6 or 8 individual fish for 100 hooks). Meanwhile, the catch rate of bottom jaring insang was about 40-60 kgs/boat/3 days trip. The catches were dominated by the family Lutjanidae in which the red snappers species (reached to 47.2% at this survey period) including Lutjanus malabaricus, Lutjanus hyselopterus, Lutjanus sebae, Lutjanus vittus, and Pinjalo pinjalo. Meanwhile the groupers (family Serranidae) were dominated by species of Epinephelus areolatus, Epinephelus malabaricus, Epinephelus microdon, and Plectropomus maculatus. Other groups were emperors (Lethrinidae) and Gymnocranius. The biological measured for Lutjanus malabaricus and Epinephelus malabaricus as a dominant landed showed the modus of length were 48 and 58 cmFL, respectivelly. Meanwhile the modus of weight were 1.8 and 2.35 kg. The growth characteristic of both species were positive allometric. It means that increasing the weight was faster than their length.


Author(s):  
Najamuddin Najamuddin ◽  
Andi Assir ◽  
Mahfud Palo ◽  
Andi Asni Najamuddin

Catching flying fish in Sendana Majene Subdistrict is carried out continuously with gill nets 1-1.5 inches. The catch of flying fish is mostly still young fish (not yet worth catching). The demand for flying fish is quite high due to the existence of special stalls of smoke fly fish around fishing settlements. Apart from smoke flying fish, dried flying fish are also sold as souvenirs. Therefore, fishermen will continue to increase production. Various results of research and field observations show that gill net is able to catch flying fish well but the size of fish caught is dominated by young fish. The effort to increase the net mesh size to 1.5 inches resulted in the diminishing number of young flying fish. Catching flying fish in Majene waters is generally carried out with drifting gill nets with mesh sizes of 1 and 1.25 inches which are very intensive every fishing season while L50 (11.92 cm) and Lm (13.59 cm) for 1 inch more net mesh size were smaller compared to the length of the first gonad maturity, in this case most of the catch is still classified as young fish (Palo, 2009). Partners are a group of flying fish fishermen. Partner problems, flying fish production is getting smaller, group capacity is not strong and group management is still weak. Partners have not been able to obtain assistance facilities from various community empowerment programs carried out by the government. The approach to be used in this service includes: identification, observation, counseling, demonstration, construction, application, assistance, field observation and evaluation monitoring. Indicators of the success of activities are measured based on the results of the application of technology compared to the results of fishing gear commonly used by fishermen. Implementation of service includes counseling, construction of fishing gear, fishing operations and assistance has been going well. The size of 1.5-inch mesh is only able to catch flying fish in a limited amount, while the size of the 1.25-inch mesh can catch flying fish in relatively large numbers. Flying fish caught with 1.25-inch mesh size has passed the size of the first gonad mature so that it supports sustainable fisheries.


2010 ◽  
Vol 11 (2) ◽  
pp. 213 ◽  
Author(s):  
T. CEYHAN ◽  
O. HEPKAFADAR ◽  
Z. TOSUNOGLU

Catch rate, CPUE, biomass ratios and size selectivity from traditional longline and trammel nets of Turkish coastal small-scale fisheries were investigated in order to describe the Smooth-hound shark (Mustelus mustelus) fishery. The SELECT method was used to estimate the selectivity parameters of a variety of models for the trammel nets inner panel of 150 and 170 mm mesh sizes. Catch composition and proportion of the species were significantly different in longline and trammel nets. While mean CPUE of longline was 119.2±14.3 kg/1000 hooks, these values for 150 and 170 mm trammel nets were 5.3±1.2 kg/1000 m of net and 12.7±3.9 kg/1000 m of net, respectively. Biomass ratios of the by catch to Smooth-hound catch were found to be 1:0.32 for 150 mm trammel net, 1:0.65 for longline and 1:0.73 for 170 mm trammel net. The estimated modal lengths and spreads were found to be 91.1 and 16.2 cm for 150 mm and 103.2 and 18.4 cm for 170 mm, respectively. The modal lengths of the species as well as the spread values increased with mesh size.


Author(s):  
Izza Mahdiana Apriliani ◽  
Alexander M. A. Khan ◽  
Lantun P. Dewanti ◽  
Achmad Rizal ◽  
Herman Hamdani ◽  
...  

Gillnet is a simple fishing gear that is widely used by fishermen in Pangandaran Regency. This study aims to determine the classification calculation of the value of hanging ratio gillnet and the catch of mackerel (Scomberomorus commerson) with different mesh sizes. This research was conducted in January 2019 in Pangandaran Regency, Indonesia. The method used in this research is the survey method. Gillnet used has 2 types of mesh sizes, 3,5 and 4 inch gill nets with each net length of 650 meters (7,312 mesh) and 750 meters (7,384 mesh). Gillnet has 12 meters with a net mesh size of 3,5 inches as many as 135 mesh and a 4 inch mesh size of 118 mesh. Hanging ratio for 3.5 inch gillnet is 0,56 while for mesh size 4 inch is 0,54. Based on these results, it can be concluded that the gill nets are selective. The proportion of catch results shows the number of target fish gill nets with a 3,5 inch mesh size is 20% and bycatch is 80%. The proportion of gillnet catches with a 4 inch mesh size shows main catch of 35,2% while the bycatch proportion is 64.8%.


Author(s):  
Jingmin Xia ◽  
Patrick E. Farrell ◽  
Florian Wechsung

AbstractWe propose a robust and efficient augmented Lagrangian-type preconditioner for solving linearizations of the Oseen–Frank model arising in nematic and cholesteric liquid crystals. By applying the augmented Lagrangian method, the Schur complement of the director block can be better approximated by the weighted mass matrix of the Lagrange multiplier, at the cost of making the augmented director block harder to solve. In order to solve the augmented director block, we develop a robust multigrid algorithm which includes an additive Schwarz relaxation that captures a pointwise version of the kernel of the semi-definite term. Furthermore, we prove that the augmented Lagrangian term improves the discrete enforcement of the unit-length constraint. Numerical experiments verify the efficiency of the algorithm and its robustness with respect to problem-related parameters (Frank constants and cholesteric pitch) and the mesh size.


2019 ◽  
Vol 10 (1) ◽  
pp. 15-23
Author(s):  
Nelwida Nelwida ◽  
Lisna Lisna ◽  
Ren Fitriadi

Gill nets is the most dominant fishing gear used by fishermen in Kampung Nelayan Village. Gill nets 2 and 3 inches are widely used by traditional fishermen and modern fishermen because this tool is very practical to catch fish also friendly to the environment. This study aims to determine the construction and friendliness of fishing gear gill nets 2 and 3 inches which include the length of the net, the width of the net, shortening, buoyancy and sinking power. This research was carried out in the Village of Kampung Nelayan, Tungkal Ilir Subdistrict, Tanjung Jabung Barat District in February 2018. The method used in this research was survey method. The data obtained were analyzed using net dimension analysis and descriptive statistical analysis. Based on the results of research on the construction of 2 and 3 inches gill nets consisting of nylon monofilament made from transparent colors. The knot used by the English knot. Top rope, float, and float buoy made from polyethylene (PE) rope and ballast rope made from polypropylene (PP). The sinker made from tin and gill net 3 inch weight based on bracelet-shaped wire.Net shortening value of 2 inch is 51.75% and has a buoyancy of 3.05 kgf and a sinking power of 9.97 kgf. As well as the value of gill shortening 3 inch 50.62% and the buoyancy generated 6.22 kgf and the sinking power of 365.4 kgf. The value of environmental friendliness of 2 and 3 inch nets has a value of 31.25 and 30.75 and is classified as environmentally friendly fishing gear.


2016 ◽  
Vol 14 (2) ◽  
Author(s):  
Vinicius J. Giglio ◽  
Hugo Bornatowski

ABSTRACT Coastal hammerheads have suffered from overexploitation and environmental degradation. We interviewed 79 artisanal fishers to verify fishery aspects, temporal changes in catches and biological aspects of the smalleye hammerhead, Sphyrna tudes , in a marine protected area on Abrolhos Bank, Brazil. Data were compared between three generations of fishers: young, middle-aged and old. Fishers' age varied between 17 and 88 years. We verified significant reductions in the weight of individuals caught by younger fishers. The main types of fishing gear used to catch S. tudes were gill nets and longlines. Overfishing through gill nets and trawl fisheries were mentioned as the cause of S. tudes population collapse in the region. The shark's diet as reported by fishers consisted of fish, crab and shrimp; austral summer was the reproductive season. A strong similarity was verified between fishers' knowledge and biological data. We suggest as plausible strategies to conserve the local population of S. tudes the reduction of net fisheries impact through zoning and establishment of no take areas. These steps can help to initiate the recovery of this depleted species.


1988 ◽  
Vol 28 (6) ◽  
pp. 809 ◽  
Author(s):  
BP Oldroyd ◽  
C Reinganum

Honeybee (Apis mellifera) colonies hived in beehive materials that had been sterilised by gamma irradiation had an average weight gain of 29.3 kg while those housed in untreated hives had an average gain of 27.1 kg.Bees sampled from both the treated and untreated colonies were examined for the presence of Nosema apis and virus, causitive organisms of stress related diseases, at the end of the season. No significant differences were found. The slight increase in weight (2.2 kg) of the sterilised colonies was not sufficient to justify the cost of prophylactic sterilisation of beehive equipment.


1966 ◽  
Vol 23 (3) ◽  
pp. 423-454 ◽  
Author(s):  
H. A. Regier ◽  
D. S. Robson

This paper re-examines five methods previously described for estimating the selectivity of gill nets as influenced by mesh size, and introduces four more. Those that appeared appropriate for lake whitefish on the basis of preliminary analysis were employed to estimate selectivity using data on whitefish from South Bay, Manitoulin Island, Ontario.The methods considered most reliable yielded estimates of selectivity curves for whitefish resembling the normal probability function with a positive skew. The length at which the mode occurred was a significantly nonlinear function of mesh size, the variance was approximately proportional to the square of the mesh size, and the coefficient of skewness not related to mesh size.An implication of these findings is that, for general sampling purposes, standard gangs in which mesh size increased in a certain geometric progression would be more efficient than those with mesh sizes in the usual arithmetic progression. The series for lake whitefish might be 1.40(1.275)x with x = 0, 1, 2, 3, 4, 5.Under the assumption that at peak efficiency all mesh sizes are equally efficient with respect to number of fish, "total efficiency" of a mesh size is defined as the area under the selectivity curve. With respect to number, we estimated that, for whitefish, total efficiency r = 12 + 5.5 (mesh size, stretch measure in inches). Here peak efficiency is taken as 100, with length units as inches. Similarly with respect to weight total efficiency r = 0.80 (mesh size)3.2. Thus with respect to weight, total efficiency increases from about 7.5 for 2-inch mesh to 100 for 4.5-inch mesh to about 200 for 5.5-inch mesh.


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