Netting specifications and maintenance of cages for finfish culture

A cage is a space enclosed with some type of mesh forming a container for aquatic animals to grow. It is typically box-shaped or tube like structure with a rope system which supports the netting material, gives shape and allows for tying to the raft unit. In box type cages, the cage is constructed of four panels at the sides and one bottom panel. Anti-predator nets are deployed around the cage to prevent entrance of predators such as sharks and sea lions into the cages. An additional net would be provided on top of the cage to prevent bird predation

Design and technical characteristics of shark gillnet operating in Mumbai coast

This paper deals with design and general features of shark gillnets operated along Mumbai coast. A PA monofilament of 0.60 to 1.0 mm diameter and selvedge meshes of PE of 1 to 2 mm diameter were used for shark set gillnets along Mumbai coast. Mesh size of the main webbing ranged from 120 to 200 mm with average of 144.4 ± 10.83 mm and rigged with a hanging coefficient of 0.41 to 0.51 with average of 0.42 were commonly used. A hung length ranging from 40 to 105 m with mean of 59 ± 10.37 with total hung depth varying from 6.42 to 10.58 m with average of 8.15 ± 0.49 m. Shark gillnet had a total length of 260 to 456 m with mean of 350.71 ± 28.53 m. The nets were operated mostly at a depth up to 18 m very near to the shore and were of set type of gillnet. Polyamide (PA) monofilament netting of 0.16 to 0.32 mm diameter and of mesh size 26-200 mm were generally used for construction of gillnets throughout the Mumbai coast. Polyamide (PA) monofilament has completely replaced PA multifilament in all the nets except those targeted i.e. white sardine and seerfish

Economic loss assessment on juvenile fish catch due to forced non-selectivity in a selective fishing gear, gillnet along Mumbai coast, India

A study on quantity and value of juvenile fish landings was carried out in the gillnet fishery of three selected landing centers along Mumbai coast viz., Versova, Cuff Parade and Mahim in India using Out board motors (OBM), Inboard motors (IBM) and non-motorised gillnetters respectively. The data on the quantity and value of landed juveniles were collected and analysed to reach a consensus on the gross economic loss on account of juvenile fishing. A bio-economic model was used to estimate economic loss due to juvenile fishing of 18 commercially important species of finfish and shellfish. A huge economic loss was recorded due to fishing of juveniles of 18 species by three different gillnet sectors. The analysis indicated that IBM gillnetters at Cuff Parade incurred maximum loss of Rs. 62.26 crores with major contribution from juveniles of seerfish followed by non-motorised gillnetter (Rs.29.98 crores) at Mahim and 25.33 crores in OBM gillnetters at Versova

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Chapter 6 of training manual "ICAR- sponsored short course on bycatch reduction in fisheries: recent advances"Not AvailableNot Availabl

Performance Evaluation of Commercially Important Indian and Imported Fishing Hooks

Fishing Technology Division, Central Institute of Fisheries Technolog

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Not AvailableThe present study on the proportion of target and non target catch in gillnet fishery from three sectors of gillnetters viz., inboard motor (IBM), outboard motor (OBM) and non-motorised gillnetter was conducted during December 2010 - November 2011 at Cuff Parade, Versova and Mahim of Mumbai coast respectively. Altogether six non target species in mesh size (12 and 14 mm), 23 species in mesh size (48 and 50 mm) and 18 species in mesh size (32 and 34 mm) were caught in selected mesh sizes targeted for white sardine (Esculosa thoracata), oil sardine (Sardinella longiceps) and catfish (Arius spp.) in OBM, IBM and non motorised gillnetters respectively. It was found that maximum target catch was observed in mesh sizes of 32 and 34 mm operated for Sardinella longiceps (oil sardine) fishery, while least was found in mesh size of 48 and 50 mm operated targeting Arius species.Not Availabl

Electrochemical characteristics of micro and nano metre sized mixtures of cerium oxide incorporated aluminium

400-405<span style="font-size:9.0pt;mso-bidi-font-size: 11.0pt" lang="EN-GB">The present study is aimed at investigating the electrochemical characteristics of aluminium due to the incorporation of nano metre and micro metre sized cerium oxide mixture. Treated aluminium exhibits higher corrosion resistance as evidenced by lower corrosion current density and corrosion rate and improved morphologies. Impedance spectra of aluminium subjected to long term exposure to 3.5% NaCl (w/v) show that the corrosion resistance of surface and internal matrix increases significantly and the corrosion is occurred in the β spaces of the aluminium. Smaller grain size and increased electronic conductivity improve the corrosion resistance of aluminium. </span

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Not AvailableFishing gears may be lost into the seas because of rough climatic conditions, damages of the gear, entanglement with bottom obstructions or dragged away by other fishing vessels or ships etc. These lost gears designated as abandoned, lost or otherwise discarded fishing gears (ALDFG) contributes to species mortality by continuing to entangle and kill fishes and other endangered/threatened species such as turtles, birds and mammals, a phenomenon referred to as ghost fishing. Passive gears like traps, gillnets may catch fish for several months or even years after they are lost. Locating ALDFG will be helpful to understand the fate and transport of lost fishing gear and to remove them from marine waters, thus eliminating its harmful impacts to species and habitats. Present study was undertaken for evidences of fishing gear losses and ghost fishing from selected areas of Indian waters. Underwater investigation by scuba diving were conducted at Enayam, Tamil Nadu & Vizhinjam coast of Kerala. About 33kg lost gears were recovered by scanning an area of 700m2 seabottom at Enayam. Six types of lost gears were retrieved in which Nylon monofilament gillnet panels (47.3%) were the predominant gear types followed by pieces of trawl codends , parts of long lines, ropes , traps , and squid jigs. Retrieved traps contained Molluscs, Arthropods, Echinoderms, Annelids and Cnidarians, Poriferans at various degrees of decomposition. From Vizhinjam coast of Kerala, gillnet webbings and ropes were recovered. This baseline information will be useful to understand the scale and distribution of ALDFG and identification of the hotspot areas of gear losses.Not Availabl

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Chapter 21 of training manual "Recent advances in harvest and post-harvest technologies in fisheries"Not AvailableNot Availabl

A Study on Technological and Operational Aspects

The fishing industry the world over is passing through a critical situation.The landings of marine fishes seemed to have reached saturation in major fishing areas of the world.As a general rule fisheries employing fishing gear and techniques used by small scale and artisanal fishermen either from shore or from onboard small fishing craft come under small-scale fisheries.This study on gill nets of Kerala, the fishing method depended upon by maximum fishermen of the state focuses on the importance of this selective and low energy fishing method in the marine fishing sector of the state.The study opens with the conceptual framework by briefly reviewing the crisis in the marine fisheries sector. Maximum fishermen depend upon gill net, which is, an important selective and low energy fishing gear. A review of relevant literature on aspects such as material, selectivity and techno-economic efficiency together with scope and main objectives of the study form the major part of the compass of the introductory chapter.This survey provided the inputs for selection of centres. The chapter presents the basis for selection of sample centres, sample units and methodology for field and experimental study.The subject matter of the fourth chapter is a basic study on gear aterials. The weathering resistance, which is an important criterion to assess the material performance, was studied for polyamide monofilament in comparison to polyamide multifilament and polyethylene twisted monofilament.The study provides supporting evidence of oxidation and characteristic C-O stretching in polyethylene and cyclic lactam .formation and presence of OH in polyamide.The study indicates that small mesh gill netting can be encouraged as a selective fishing method in the inshore waters with restrained use of 30 and 32 mm mesh sizes. The economic efficiency was assessed using standard indices such as rate of return, internal rate of return, pay back period, fishery income, energy efficiency and factor productivity. The effect of size and cost of capital and cost of production on the economics of operation is also discussed in this chapter. It was observed that level of technology did not have direct effect on economic performance.Cochin University of Science and TechnologyIndustrial Fisheries, Cochin University of Science and Technolog