Drift Gillnetting for Large Pelagics in the West coast of India with special reference to Tuna Research Guide Dr. Saly N.Thomas Principal Scientist External Expert Dr.Leela Edwin Muhammed Sherief P.S Research Associate

Scope of Research Changes are observed in gillnet fishing in India over the years , as in the form of introduction of new gear material, mechanization of fishing vessel and net hauling equipment. So a study on the present status and details of fleet structure of gillnet fishing is relevant in this context. Through large mesh drift gillnetting this study intends to create an understanding on the distribution, abundance, and habitat of tuna and other large pelagics in the west coast of India. In high sea drift gillnetting, the cost of gear accounts for 44% to 56% of the total investment (Thomas, 2001). So, a study on material substitution of polyamide with new generation gear material and optimized design is necessary The major problem in drift gillnetting is bycatch, which includes marine mammals, sea turtle, sea birds and non targeted fish species (Boopendranath, 2012). There is a paucity of information on bycatch associated with gillnet fisheries throughout the Indian coast.

Objectives To understand the present status of large mesh tuna drift gill netting of west coast of India To optimise the design of cost effective drift gillnetting through material substitution. To analyze the technical and economic efficiency of the high sea drift gillnetters of the west coast of India To assess the bycatch from gillnetting on quantitative and qualitative basis

Methodology: The current status of large mesh drift gillnetting operations in the west coast of India will be investigated by direct observation and by interviewing the fishers using questionnaires (Sree Krishna & Shenoy (2001) and Thomas & Hridayanathan (2002). Design documentation as per Nedelec (1975). Experimental fishing with design modified and material substituted gillnets will be conducted to compare the catching efficiency and profitability (Thomas, 2001). Bycatch issues in drift gillnetting will be estimated through onboard observation and direct interview using structured questionnaire (Yousuf et al., 2008 )

Introduction Tuna and tuna-like fishes are important both from global demand and economic view points. Globally, in terms of fishing gear, 63% of the catch is made by purse seining, followed by longline (12%), pole and line (10%), gillnets (4%) and miscellaneous gears (11%)( ISSF, 2015). In India, major share of the tuna catch realized was from gillnets (51.6%) followed by purse seine (19.9%), hooks and line (12.2%) and small quantities (12.1%) (CMFRI, 2014). Global drift gillnet operation Reference Indian ocean, Atlantic, Pacific Mediterranean sea countries Northridge, 1991; Abdussamad, 2012; Satheesh Kumar and Pillai, 2014 Algeria, Morocco, Spain, France, Italy, Malta, Greece, Turkey, Pakistan, Indonesia, India, Iran, Oman and Somalia EJF, 2007; Moazzam, 2012; IOTC, 2013

Introduction Drifting gillnets are set close to the surface or below it with the use of floats. These nets drift freely with the current, either separately or with the boat to which they are attached (Nédélec and Prado, 1990)

Design of typical tuna drift gillnet

Drift gillnetting in India Indian tuna fishery comprises coastal fishery and oceanic fishery (Somvanshi et al., 1998); constituted by motorised and mechanised sectors (Thomas,2010). Total numbers of gillnetters in India increased from 2,362 in 1980 to 20,257 in 2010 (CMFRI, 1981, 2012). During 80’s the length of gillnets operated varied from 800- 1890 m (Silas et al., 1984; Boopendranath and Hameed, 2013); during 1990s around 2150 m (Vijayan et al., 1993; Ganga et al., 2008; Thomas, 2010) ; during 2009-2010, 10000 m (Thomas, 2010); while during 2014 upto 16000 m (Edwin et al., 2014). Motorised gillnet sector comprise of wooden ,Fibre Reinforced Plastic(FRP) and marine ply wood canoes( 7 - 12 m LOA fitted with 15 to 25 hp OBM (Madhu et al., 2002; Ganga and Pillai, 2006; Thomas, 2010). Presently, mechanized gillnetters targeting tuna are of 8 to 19 m LOA fitted with 24 to 193 hp engines (Edwin et al, 2014).

Material of construction Till late 1950s, hemp and cotton were used for gillnets which was later replaced by nylon multifilament twine (Vijayan et al., 1993). In early 90s, the nylon monofilament was introduced and by 2000, monofilament almost completely replaced nylon multifilament in the gillnet sector in many states of India (Vijayan et al., 1993; Rao et al., 1994; Pravin et al., 1998; Pravin and Ramesan, 2000; Thomas, 2001; Thomas et al., 2005; Chaidee et al., 2007). Gill nets for tuna and other large pelagic fishes are mainly made of PA multifilament of 2l0dx6x3 to 210dx12x3 netting (Thomas, 2010). HDPE yarn and HDPE twine was found to be on par with nylon for large pelagics (Pillai et al .,1989; Thomas &Hridyanathan, 2003; Pravin et al., 2009). In Gujarat, Andhra Pradesh and Tamil Nadu, HDPE is used as drift gillnet material along with nylon(Rao et al.,2002). Recently, materials like sapphire a highly modified form of PE was found used for large mesh gillnet in certain pockets of Gujarat (Sherief et al.,2014).

Mesh size Mesh size Target fish Reference 60 -115 mm Tuna, seerfish, shark Jude et al., 2002 237 mm Tuna Hossini , 2003 60-135 mm Neethi selvam and Jude , 2006 120- 150 mm Tuna , swordfish,shark 145 mm Mehran et al., 2009

Operational parameters Up to 1990s, mechanized drift gillnetters carried out single day fishing trips and started switching over to two and three day trips (Silas et al.,1984, Boopendranath and Hameed, 2013). By late 90s , trips of one week and two weeks were common (Thomas , 2001). By 2010, mechanised gillnetters were undertaking multiday fishing extending up to 30 days (Thomas, 2010) and now this is extended up to 45 days (Edwin et al., 2014). Gillnet cum longlining is a very common practice contributing to more than 75 % of the total tuna fishing in the country (Balasubramaniam, 2000). Operational parameters

Operational parameters High sea drift gillnetters operated by Tamil Nadu fishermen operate up to depth of 1000 m for catching tunas, sharks, skates, rays and chimaeras (Joshi et al., 2008; Akhilesh et al., 2009) Recently net haulers were found used in large mechanised gillnetters operated by Tamil Nadu fishermen (Edwin et al., 2014). In gillnetter cum longliners, hydraulic line haulers are fitted behind the wheel house (Edwin et al., 2014).

Catch composition From 2000 onwards, the species composition of drift gillnets was diverse in nature due to the expansion of fishing ground to oceanic and deeper waters (Akhilesh et al., 2012). Catch of drift gillnet for large pelagics comprised mainly tuna, swordfish, sail fish, seer fish , shark etc . However, a detailed information on catch composition and size statistics is lacking (Yousuf et al ., 2008)

Techno-economic feasibility In the Indian context, techno-economic aspects of purse seine was studied by Mukundan and Hakkim (1980); Verghese (1994); Panikkar et al. (1993) and Shibu (1999) and of trawling by Iyer et al., (1985); Devaraj Smitha (1988); John (1996) and Shibu (1999). Economic aspects of marine gillnets operated in Kerala were studied by Iyer et al., (1993), Shibu (1999), Panikker et al., (1993). Techno economic efficiency of gillnets along Kerala coast was reported by Kurien (1982), Thomas (2001). In high sea drift gillnetting, the cost of gear is accounted for 44% to 56% of the total investment (Thomas, 2001). One way of reducing the cost of the gear is by substituting the material with a less costly but durable material.

Bycatch problem Bycatch occurs in virtually all fisheries. Bycatch is the unintended catch in a fishing operation of species other than the target species, or individuals of the target species that are of undesirable size. Bycatch can either be discarded or landed (ISSF,2015). Though bycatch was considered as a problem mainly in the trawl sector, wide spread use of large scale drift gillnets resulted this, applicable to this sector also (Northridge, 1991). In terms of important bycatch issues in the tuna fisheries of the Indian Ocean, the catch of marine mammals and sea turtles is often mentioned and there is some concern about shark bycatch, mainly in the gillnet fisheries . Tuna gillnet bycatch mainly consists of Scombroids followed by barracuda, dolphin fish, thresher shark, silky shark, other requiem sharks and black marlin, striped marlin, mako, mantas and Indo-Pacific sailfish (Moazzam, 2011;2012).

Gillnet by catch Species Reports Cetaceans Cockcroft &Krohn, 1994; Perrin et al., 1994;Archer et al., 2001; Wise et al., 2001; Read et al., 2006. Kumarran (2012), Jayaparkash et al. (1995), Mohan (1985) Pillai and Chandrangathan (1990), Silas et al. (1984) and Yousufet al. (2008 ) Lal Mohan, 1994, Yousuf et al., 2008) Sea bird Zydelis et al. 2009; Croxall et al, 2012; Løkkeborg, 2008, Merkel 2004, Christensen-Dalsgaard et al. 2008, , Žydelis et al,2009) Waugh et al., 2011 Turtle Rajagopalan et al., 1996;2002; MARG, 2012; Lobo, 2007; Bhoopathy and Karunakaran , 2003, Shark Clarke et al. 2007, Walker 1998, Kelleher 2005, Fowler et al. 2005, Bonfil 1994; Stevens et al.,2000; FAO 2009; Akhilesh et al., 2011

Target S p e c i s B Y C A T h S p e c i Group Species Species Tropical tunas Yellowfin tuna Bigeye tuna Skipjack tuna Temperate tunas Albacore Southern bluefin tuna (CCSBT) Bilfish Swordfish Black marlin Blue marlin Striped marlin Indo-Pacific sailfish Neritic tunas Longtail tuna Frigate tuna Bullet tuna Kawakawa Seerfish Narrow-barred Spanish mackerel Indo-Pacific king mackerel B Y C A T h S p e c i Species Sharks and rays Highly migratory species of sharks (e.g. blue, makos, oc. whitetip, silky, thresher, porbeagle) and rays (e.g. manta rays, pelagic stingrays) Marine turtles Green, hawksbill, leatherback, loggerhead, olive ridley, flatback Seabirds Several species of albatross, petrels and shearwaters Marine mammals Several species of toothed and baleen whales Other finfish Other tuna species and other non- targeted, associated and dependent species

Conclusion Only few researchers have addressed drift gillnet fishing for large pelagics in Indian waters. Coastal tunas have been exploited from Indian waters both as targeted catch and as incidental bycatch since very long and the production reached very close to their estimated potential. Changes are observed in gillnet fishing in India over the years, as in the form of introduction of new gear material, mechanization of fishing vessel and net hauling equipment. As the volume of gear used is becoming larger year after year, the investment on gear is also increasing. Material substitution of polyamide with new generation gear material and optimized design is necessary to reduce the cost without compromising on the catching efficiency. There is a paucity of information on bycatch associated with drift gillnet fisheries throughout the Indian coast There is a need to assess the level of bycatch quantitatively and qualitatively .

Progress of work Details of large mesh drift gillnet systems operated along the west coast of India were collected and compiled. New generation fishing gear materials procured and material properties being tested. Experimental gillnets using new generation material designed. Experimental gillnet along with control gear fabricated and arrangements being made for experimental trials.

Thanking you for your attention