Effect of steel wire and claw size on the sea snail ( Rapana venosa ) catch in a Black Sea beam trawl fishery (original) (raw)
Related papers
Turkish Journal of Fisheries and Aquatic Sciences, 2017
At constant speed and revolutions per minute (rpm), the effect of beam trawls on fuel consumption and towing resistance in sea snails (Rapana venosa Valenciennes, 1846) fisheries were measured by a fuel flow meter and force gauge. A traditional beam trawl was used to capture sea snails. Three different sledges (one traditional, T, and two modified, M-1 and M-2) were compared for differences of fuel consumption and towing resistance on two sea ground types (sandy and sandymuddy) during the fishing operation. Beam trawls were observed by underwater video cameras. Trawl hauls with a 10 min towing duration were carried out from July to September 2015 in the southern Black Sea (Turkey). M-1 had the lowest fuel consumption on sandy bottoms and sandymuddy bottoms at constant rpm and speed (P<0.0001). Although the other sledges (T and M-2) had low towing resistance in some cases, M-1 was found to be slightly better than the other sledges (P<0.0001).
By-catch in the commercial beam trawl fishery for Rapa Whelk in the Black Sea
Mediterranean Marine Science
In this work, the by-catch was investigated in commercial beam trawls used in the rapa whelk (Rapana venosa) fishery, in trials at sea between September 1, 2015 and April 30, 2016. Four commercial boats using beam trawls were chartered and catch data was collected from a total of 87 hauls. Hauls were performed between 7.1–28.3 meters deep for a duration of 20–77 minutes and haul speed varied between 1.4 – 2.7 knots. A total of 28 by-catch species were identified, which amount in average to 11.4% of the total number of specimens in the by-catch. Two different groups were identified in the by-catch (G1: 7-18 m, G2: 19-26 m) according to depth. Although there is a reduction in the amount of by-catch for G2 group, no significant difference was found between groups (p>0.05). According to Generalized Additive Models (GAM) results, the variables affecting the by-catch amount were identified as fishing area, depth, haul duration, and amount of captured rapa whelk (p<0.01). In addition...
Construction Characteristics of a Beam Trawl for Catching Young Shrimps in Estuaries
2010
Faced with the difficulty of catching young shrimp individuals in estuaries, a beam trawl was developed and tested. It was effective in catching shrimps measuring between 2.7 and 11.5 mm in length and crabs of 5.99 to 6.64 mm in length. The equipment is resistant to corrosion and can be maneuvered by one person. The net fastening system is easy to operate, allowing its removal after every trawl, thus avoiding possible sample losses with onboard handling. The ideal trawling time was around 3 minutes and use of a ballast system gave better results during the catching operation, although without any statistical difference.
Bycatch in 36 and 40 mm PA Turkish twin rigged beam trawl
The Turkish twin rigged beam trawl which has two identical nets rigged side by side on the same beam targets mainly the Parapenaeus longirostris, although some bycatch fish species have also become target species. Thus, landings of the shrimp beam trawling fleet also include some commercially valuable fishes. Our study focused on the bycatch commercial species which are caught by the beam trawl fishery with nominal mesh sizes 36 and 40 mm PA (diamond) codend in the Sea of Marmara (Turkey) and also on the minimum landing size (MLS) established for Merluccius merluccius, Merlangius merlangus euxinus, Mullus surmuletus, Trachurus trachurusand Pomatomus saltatrix. Since there was no MLS value for Spicara smaris, the length at first maturity (LFM) was used for this species. Experiments were carried out onboard the commercial beam trawler. In 20 hauls, the average codend catch weight was 63.12 kg for 36 mm PA and 66.51 kg for 40 mm PA. On the other hand, for 36 mm PA, 83.5% of M. merluccius, 74.3% of M. merlangus euxinus, 29.7% of T. trachurus, 10.8% of P. saltatrix and 8.6% of M. surmuletus were below the MLS. For 40 mm PA, 88.9% of M. merlangus euxinus, 87.7% of M. merluccius, 42.5% of T. trachurus, 7.2% of P. saltatrixand 6.7% of M. surmuletus were below MLS. In addition, 7.5% of S. smariswere below length at first maturity (LFM) for 36 PA codends
2022
The effects on target catch, bycatch and discard of using multifilament and monofilament sardon on the trammel nets in the black sea small scale fisheries. Acta Ichthyol. Piscat. 00 (0): 00-00. Background. In the Sinop region, many species are caught as non-targets during the target species catching with gill nets. Sardon was used to prevent the bottom creatures (crabs, snails, etc.) climbing these nets used on the ground from climbing. This study was carried out in 13 fishing operations in the inner harbor area of Sinop, from September through November of 2004. Trammel nets were used, which has 32 mm mesh size and target fish species of the fishing gear is red mullet (Mullus barbatus) in the study. Materials and methods. Three net groups were used in the experiments, without sardon (A0) for the control net, multifilament with sardon (A1) and monofilament with sardon (A2) respectively. Results. 65.3% Osteichthyes fish (696 specimens), 16.8% Mollusca (179 specimens), 16.4% was arthropoda (175 specimens) and 1.5% was Chondrichthyes fish (16 specimens) Author-formatted, not peer-reviewed document posted on 12/12/2022.
Reducing bycatch in beam trawls and electrotrawls with (electrified) benthos release panels
ICES Journal of Marine Science: Journal du Conseil
Benthos release panels (BRPs) are known for their capacity to release large amounts of unwanted benthos and debris, which can decrease mortality on these animals and eases the on board sorting process aboard demersal beam trawlers. They can reduce the bycatch of undersized fish, which is desired once the European discard ban is implemented. However, unacceptable commercial losses of sole (Solea solea L.) and damage to the BRP as a consequence of suboptimal and unsuitable rigging in the traditional beam trawl with chain mat, is hampering a successful introduction in commercial beam-trawl fisheries. To eliminate these drawbacks, square-meshed BRPs with different mesh sizes (150, 200, and 240 mm) were rigged in a trawl with square net design as used in electrotrawls and tested for selectivity. In addition to this, the effect of electric stimulation at the height of the BRP to eliminate the loss of commercial sole was examined. According to our observations, no abrasion of the net attri...
Catch and by-catch composition of the shrimp fishery by beam trawl in the southeastern Marmara Sea
Ege Journal of Fisheries and Aquatic Sciences, 2006
Catch and by-catch composition of the shrimp fishery by beam trawl in the southeastern Marmara Sea. This study has been conducted over a period of one year between November 2000-October 2001 in the southeastern Marmara Sea. In addition to the weight and abundance distribution of the deepwater rose shrimp Parapenaeus longirostris which form the prime target species of the beam-trawl, the composition of the by-catch, length distribution of species caught and their numerical abundance ratios in the total catch were investigated. The pooled data indicated that the target species Parapenaeus longirostris formed 64.5% and the by-catch the remaining 35.5% of the total catch. Of the total 50 species that make the by-catch, 17.16% belong to Osteichthyes, 8.58% to Crustacea & Decapoda, 4.94% to Echinodermata, 2.53% Mollusca, 2.14% to Cnidaria and finally 0.13% to Chondrichthyes. It was observed that Goby, Whiting, Flounder, Crab, Sea-star and Sea cucumber formed the majority of the total catch after Parapenaeus longirostris.
Journal of Fisheries Science, 2022
Anchored fish aggregating devices (AFADs) have been widely used for fishing in Thai waters. However, abandoned, lost, and discarded fishing gears (ALDFGs), including lost AFADs, may cause environmental impacts. Fishing gear marking (FGM) is considered as a tool to help identification of ALDFGs. The main objective of this study is to compare the durability represented by the percentage of remaining condition (R-value) of three material types of FGM applied for AFADs, i.e., stainless steel (SS), colored acrylic (CA), and polypropylene (PP). This study was carried out using 50 AFADs deployed in the Gulf of Thailand (GOT) and the Andaman Sea (ANS) between July and October 2020 in cooperation with 10 fishers. The AFADs were deployed in similar habitat (bottom depth and type) between the GOT and the ANS. The three material types of FGM were assumed to be sufficiently durable to last for the lifespan of the AFADs in both the GOT and the ANS (within 2 months and 3.5 months, respectively) though some FGMs in the ANS were detached from cable ties or broken before AFADs were lost. The loss of AFADs and FGMs was mainly caused by adverse weather condition (rough sea). Only data from the ANS was included in comparative analysis due to the insufficient variance data obtained from the GOT. The analysis revealed that SS had the higher durability than CA and PP when the AFADs lasted for less than 3.5 months. As a result of our study, some recommendations were made. For example, the cable ties can be replaced by ropes or threads to improve the installation method. This study serves as a basis to develop FGM and to support responsible fisheries. Beneficiaries of the study include fisheries policy makers, managers, and fishers.
Turkish Journal of Fisheries and Aquatic Sciences
In this study, by-catch reduction in trammel nets used for prawn fishery in İzmir Bay was studied between May and October 2003. In shrimp trammel net fishery catching of discard species is an important problem due to a series of reasons such as disentangled species causes extra work for fishermen and decreases the labour life of nets. A Guarding net was attached to lead line of traditional shrimp trammel net as a modification to minimize this problem. Control Nets (CNet) originated from traditional commercial nets and were compared against two groups of Experimental nets (Exp1 and Exp2) in two periods. In the first period of the study, Exp1 net group caught 36.46% fewer shrimp (Melicertus kerathurus) in comparison to CNet. In addition to this, 35.62% crab (Goneplax rhomboides), 40.71% mantis shrimp (Squila mantis) and 44.77% purple dye murex (Bolinus brandaris) were caught fewer than those in CNet net group. In the second period of the study, Exp2 net group was put into the trial. In this period, Exp1 net group compared with CNet net group caught less shrimp (8.09%), crab (66.15%), mantis shrimp (26.79%) and purple dye murex (32.25%). Exp2 net group caught fewer shrimp (0.99%), crab (50.63%), mantis shrimp (17.33%) and purple dye murex (25.92%) than CNet net group. This study indicates that the net modification was capable of reducing bycatch. Rising of trammel net above the lead line from muddy ground prevents discarding of demersal species from net. Therefore, the height of guarding net is an important criterion for bycatch reduction.