Fishing provides major source of food for the humanity and provides employment and economic

benefits to large sections of the society. As a source of food it contributes about 20 percent of animal protein

supply. At present the total world capture fishery production is around 95 million tonnes. About 70 percent

of the production is directly utilised for human consumption while the balance 30 percent is reduced into

fishmeal and used in animal feed productio

Boopendranath, M R

CMFRI Digital Repository

CMFRIWinter School onImpact of Climate Changeon Indian Marine FisheriesLecture NotesPart 1Compiled and Edited byE. Vivekanandan and J. JayasankarCentral Marine Fisheries Research Institute (CMFRI),(Indian Council of Agricultural Research)P.B. No. 1603, Cochin - 682 018, Kerala(18.01.2008 - 07.02.2008)CMFRI - Winter School on Impact of Climate Change on Indian Marine Fisheries 123Fishing practices in the context of climate changeFISHING PRACTICES IN THE CONTEXTOF CLIMATE CHANGEM.R. BoopendranathCentral Institute of Fisheries TechnologyP.O. Matsyapuri, Cochin-682 029, India(boopendranath@hotmail.com)IntroductionFishing provides major source of food for the humanity and provides employment and economicbenefits to large sections of the society. As a source of food it contributes about 20 percent of animal proteinsupply. At present the total world capture fishery production is around 95 million tonnes. About 70 percentof the production is directly utilised for human consumption while the balance 30 percent is reduced intofishmeal and used in animal feed production.Fishing is an ancient occupation and has been in practice since the Palaeolithic period. About 200million people are either directly or indirectly involved in fishing in the world. Fifty million people ofwhom 12.5 million are fishermen and their family members directly depend on fishing for their livelihood.An additional 150 million people are involved in shore-based support activities, processing and marketingof fish and fish products. Fishing contributes significantly to foreign exchange earnings of many developingcountries.Fishing vessels The world fishing fleet numbered about 3.8 million vessels in 1995. About one-third of these weredecked vessels, the remaining two-thirds were un-decked vessels, generally less than 10 m in length. Thereis great diversity in fishing vessels operating around the world that may range from a 2-metre dugout canoeto factory trawlers exceeding 130 metres in length, where trip durations range from a few hours to over ayear.Introduction of the use of ice and refrigeration machinery has greatly increased the ability of thevessels to handle, process and store fish in good condition onboard. Technological developments, such ashull design optimisation, improvement in engine performance including turbo charging, hydraulic haulingmachinery, improved navigation equipments, fish finding electronics had major effects on the efficiencyand profitability of fishing vessels. The introduction and widespread use of the outboard engine has greatlychanged small-scale fishing operations in developing countries.Major developments have taken place in fishing vessels in craft materials, hull optimization, engineperformance, propulsion systems, gear and catch handling deck equipment, onboard pre-processing,processing, preservation and packaging systems, and energy conservation. In modern large fishing vessels,the command console resembles the aircraft cockpit. The navigation controls and main displays are shownon monitors in front of the control position and increasingly these are shown on one large integrated display.Navigation instruments, fish detection devices such as sonar and radio communications are the importantinstruments used in fishing vessels.In India, 2,38,772 fishing craft of various sizes and classes are under operation, consisting  of 58,911mechanized boats, 75,591 motorized craft and 104,270 non-mechanized craft (CMFRI, 2005). About 49.7%of the mechanized vessels are trawlers, followed by gillnetters (24.1%), dol netters (15%), liners (2%) andpurse seiners (1.7%) and others (7.6%). A few deep-sea fishing vessels of more than 20 m overall length areoperating along the east coast based at Visakhapatnam, targeting shrimp resources in the north-east coast.Mechanised fishing sector produced 66% of the marine landings, followed by motorized sector (27%) andartisanal sector (7%) during 2003. While the landings from mechanised sector increased from 1.33 millionCMFRI - Winter School on Impact of Climate Change on Indian Marine Fisheries 124Fishing practices in the context of climate changetonnes in 1991 to 1.66 million tonnes in 1996, that of non-mechanised sector decreased from 0.42 milliont to 0.27 million t. The landings from motorized sector during this period remained more or less the same,fluctuating between 0.33 million t and 0.46 million t.Fishing gear materialsTraditional fishing gears used in earlier years were less effective with low productivity. They weremade of natural fibres such as cotton, manila, sisal, jute and coir. As these materials are vulnerable to bio-degradation, they have relatively short service life and incur high cost for maintenance. In recent decadesmajor advances have taken place in fibre technology along with introduction of modern materials. With theintroduction of man-made synthetic fibres in India in the late 1950s, natural fibres used for the fishing gearshave been substituted by these synthetic materials due to their high breaking strength, high resistance toweathering, low maintenance cost, long service life and better uniformity in characteristics. Most importantsynthetic fibres used in fisheries are polyamide (PA), polyester (PES), polyethylene (PE) and polypropylene(PP). Other synthetic fibres, which are less widely used and generally restricted to Japanese fisheries, arepolyvinyl alcohol (PVAA), polyvinyl chloride (PVC) and polyvinylidene chloride (PVD).  The introductionof synthetic materials with high tensile strength has made changes in the design and size of fishing nets.Earlier, nets were fabricated manually, which was laborious and time consuming. In recent years, machinemade nettings are used almost exclusively.Fishing gearsA wide array of fishing gears and practices ranging from small-scale artisanal to large-scale industrialsystems are used for fish capture. Over the years, traditional fishing gears have been upgraded and moreefficient fishing systems have been introduced. Most important among these fishing gears are trawls, purseseines, lines, gillnets and entangling nets and traps. Among the most significant developments which affectedthe historical evolution of fishing gear and practices are (i) developments in craft technology andmechanisation of propulsion, gear and catch handling, (ii) introduction of synthetic gear materials, (iii)developments in acoustic fish detection satellite-based remote sensing techniques,  (iv) advances in electronicnavigation and position fixing equipment, and (v) awareness of the need for responsible fishing to ensuresustainability of the resources, protection of the biodiversity and environmental safety and energy efficiency.Fishermen use several fishing gears and methods that are appropriate for the species and  environmentaland ground conditions. Fishing gears whether primitive or sophisticated use five mechanisms in the captureprocess viz., gilling and tangling (e.g. gill nets and trammel nets), trapping (e.g. traps, pound nets), filtering(e.g. trawls, seines and other net fishing systems), hooking and spearing (e.g. hook and line, harpoons), andpumping (e.g. fish pumps).Fishing gears are classified based on the principles of capture, design and technical features andoperational methods. FAO defines and classifies the main categories of fishing gear as follows:• Surrounding nets (including purse seines);• Seine nets (including beach seines and boat, scottish/danish seines);• Trawl nets (beam, otter and pair bottom trawls, otter and pair midwater trawls);• Dredges;• Lift nets;• Falling gears (including cast nets);• Gillnets and entangling nets (including set and drifting gillnets; trammel nets);• Traps (including pots, stow or bag nets, fixed traps);CMFRI - Winter School on Impact of Climate Change on Indian Marine Fisheries 125Fishing practices in the context of climate change• Hooks and lines (including handlines, pole and lines, set or drifting longlines,trolling lines);• Grappling and wounding gears (including harpoons, spears, arrows, etc.);• Stupefying devicesIn the past, technological development of fishing gear and methods was aimed at increasing production,by increasing efficiency of the gear systems. However, in the present situation of overfishing, increasedawareness of the environmental and ecological impacts of fishing, the fishing gear development is focusedon development of responsible fishing gear systems with improved size-selective and species-selectiveproperties, decreased impact on the environment and non-target resources, and sustainability of fish stocks.Among the great variety of harvesting systems available around the world, the most significant incommercial fisheries are purse seines and trawls, followed by lines, gill nets and entangling nets and traps.Surrounding nets are roughly rectangular walls of netting rigged with floats and sinkers, which afterdetection of the presence of fish are cast to encircle the fish school. Surrounding nets are generally operatedin the surface layers. Purse seines are the predominant type of surrounding nets, in which the bottom of thenet is closed after encircling the fish school, by a purse line. Mini purse seine or ring seine used in thetraditional motorized sector belong to this category. Seine net is a long wall of netting supported by floatsand sinkers, which are operated by surrounding areas of water with potential catch. They are usually operatedin the coastal or shallow waters where bottom or surface act as natural barriers. Trawl nets are conical bagnets with two wings and a codend where catch is concentrated, operated by towing from one or two boats.Based on the position in water column where they are operated, trawls are classified into midwater trawls orbottom trawls. Gill nets are entangling, rectangular walls of netting kept erect by means of floats and sinkersand positioned in the swimming layer of the target fish, which catch the fish by holding them in the mesh bygilling or entangling.GPS, acoustic fish detection and satellite-based remote sensing techniquesDevelopment of Global Positioning system (GPS), acoustic fish detection and satellite-based remotesensing techniques has enormously increased the precision and efficiency of fishing operations. The mostwell known and widely used instruments for fish detection are echosounder and sonar. Echosounders areused for (i) depth recording for navigation purposes and position fixing; (ii) ground or sea bed discriminationi.e., to distinguish soft mud, sand, gravel and rock bottom conditions; (iii) determination of sea bed contour;(iv) location of wrecks and hazardous areas; and (v) location of fish and determination of its depth ofoccurrence. Technological advances in electronics and research into underwater acoustics have led totremendous improvements in echo sounder and sonar and made them more reliable and affordable. Sonar isan indispensable tool for detection of schools, during aimed midwater trawling and purse seining.Progress in the satellite-based remote sensing techniques, which use sea surface temperature andocean colour to identify areas of potential fish abundance also greatly reduces the search time, as near-realtime information is communicated to the fishermen.  Indian National Centre disseminates PFZ Advisoriesfor Ocean information Services (INCOIS, Hyderabad) (autonomous body under Department of OceanDevelopment), on Tuesdays, Thursdays and Saturdays to around 200 nodes covering the entire coastline ofIndia.Responsible fishingUntil the Second World War, when fishing pressure was of moderate intensity, fishery resourceswere widely believed to be inexhaustible. Dynamic developments in the harvest and post-harvest technologyof fish took place in the post-war era. Introduction of powerful and highly efficient fish harvesting systemsand fish detection methods, and an uncontrolled expansion in fleet size fuelled by ever increasing marketdemand for fish brought about increasing pressure on the world fishery resources. Unmistakable signs ofCMFRI - Winter School on Impact of Climate Change on Indian Marine Fisheries 126Fishing practices in the context of climate changeA few major fishing gearsPurse seineDrift gill netDrift long lineTrapOne boat bottom otter trawtoverfishing and negative impacts on the ecosystems have increasingly manifested in the recent years,highlighting the need for scientific management of the world fishery resources in order to ensure their long-term sustainability and availability to the future generations. The FAO Code of Conduct for ResponsibleFisheries was adopted in October 1995. The Code covers conservation; management and developmentof fisheries; capture, processing and trade of fish and fishery products; aquaculture; fisheries research; andintegration of fisheries into coastal area management. Responsible fishing would ensure the long-termsustainability of the resources, minimise negative environmental impacts and protect biodiversity.Climate change and fishing practicesClimate change strongly influences the distribution and abundance of fishes (Wood and McDonald,1997; Brander et al., 2003; Hobday et al., 2006). Global climate change results in latitudinal shift in oceantemperature (Bakun, 1990), which is predicted to drive species ranges toward the poles (Parmesan andYohe, 2003). Where dispersal capabilities are limited, as for example due to physical barriers, and whenhabitats are unsuitable, widespread collapses of fish stocks may occur. Changes are also expected in growth,survival, reproduction, or responses to changes at other trophic levels (Beaugrand et al., 2002; Beaugrandet al., 2003). These changes may have impacts on the nature and value of commercial fisheries. Species-specific responses are likely to vary according to rates of population turnover. Fish species with more rapidturnover of generations may show the most rapid demographic responses to temperature changes, resultingin stronger distributional responses to warming (Perry et al., 2005).CMFRI - Winter School on Impact of Climate Change on Indian Marine Fisheries 127Fishing practices in the context of climate changeWhile the principles of capture and the prevailing gear systems will continue to persist in the changingfisheries scenario, design requirements of craft and gear, operational and gear handling parameters mayrequire significant changes to suit the emerging non-traditional fish species and shifting traditional fishstocks. Small-scale fishing will be more significantly impacted due to shifting of traditional fish stockscompared to large-scale fleet operations that can follow the shifting fish stocks.Climate change is projected to result in irreversible changes in rainfall, ocean and wind currents andincreases in mean sea level, which may strongly impact on small-scale fishing operations. Intensity ofcyclones and storms may increase with global warming, making fishing operations a riskier occupation.References and further readingBakun, A. 1990. Global climate change and intensification of coastal ocean upwelling, Science 247, 198-201.Beaugrand, G., Brander, K. M., Lindley, J. A., Souissi, S. and Reid, P. C. 2003. Plankton effect on codrecruitment in the North Sea. Nature, 426, 661-664.Beaugrand, G., Reid, P.C., Ibanez, F., Lindley, J.A., Edwards, M. 2002. Reorganisation of North Atlanticmarine copepod biodiversity and climate, Science, 296, 1692-1694.

Fishing practices in the context of climate change

 -Winter School on

Impact of Climate Change on Indian Marine Fisheries held at CMFRI, Cochin 18.1.2008 to 7.2.2008

http://eprints.cmfri.org.in/5346/1/23.pdf

Fishing practices in the context of climate change -Winter School on Impact of Climate Change on Indian Marine Fisheries held at CMFRI, Cochin 18.1.2008 to 7.2.2008

Abstract

Similar works

Full text

Available Versions

CMFRI Digital Repository