The ecological relationship between fishes and their environment is of great practical application in fisheries. For any large scale development of our fishery

resources a better understanding of the environmental factors influencing the reSources is essentia

Kumaran, M

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Our fisheries resources and ~he role of upwelling in ~heir fluc~ua~ions Part 1* MARINE FISH PRODUCTION OF INDIA M. KUMARAN Pelagic Fishery Project, Cochin-16 The fisheri es of the fndi an region, are suppo rted by a large number of pelagic ..,d, demersal fishes which are exploited by aried types of craft and gear. The fishing mustry in India is passing through a phase of chang ing over from the traditional to the modern methods of exploitation, from the use of indigenous sailing craft and rather less effective gear to fishing w ith the help of mechan ised craft and the larger powered vessels operating the more effi-cient types of fishing gear and other ancil-liaryequipments as the radars , fish finders etc. Exploration and harvesting of the fish-eries resources of the ocean depths and high seas and a more intens ive appl ied fisher ies research especially in the field of processing is of considerable importance to the country. The object of this series is • This is the first of a series of 3 papers by the author. January, 1978 to present a brief account of the recent findings on the regional and seasonal dis-tribution of the major exploited marine fishery resources, potential fisheries re-sources available for exploitation and on the influence of upwelling on the wide fluctuations in the availability of fisheries resou rees. The ecological relationship between fishes and their environment is of great practical application in fisheries. For any large scale development of our fishery resources a better understanding of the environmental factors influencing the re-Sources is essential. Marine biological and oceanographical investigations in recent years have provided very interesting infor-mation on biological and non-biological factors of the environment. 51 Non-biological factors influenc ing fi sh-eries include winds, monsoons, currents, tides, nature of bottom, light, temprature, salinity, pH , nutrient salts etc. Influence of the south-west monsoon on the sea surface is manifested in upwelling along the west coast of India. It has been found that mon-soon intensities of certain higher range and associated vertical circulation off the coast is favourable for successful fisheries. In view of this, it is felt desirable to dis-cuss the fluctuations in fisheries and the effect of upwelling on to the continental shelf of cool, oxogen low intermed iate waters of the Arabian Sea on the fisheries resources available espeCially on the south-west coast of India. Before proceeding to detail the influence of upwelling, a general outline of the fluctuations as observed in the exploited marine fisheries resources will be useful. Marine Fish Production along the coasts of India India has a coastline of about 5,650 km. The annual marine fish production in Ind ia for 1974 and 1975 have been esti-mated at 1.218 and 1.423 million tonnes respectively. The overall picture of the present status of the exploited marine fishery respurces will be useful to under-stand the flu ctuations in fisheries. In Table 1 some facts on our exploited marine fishery resources are given in order to high-light the trends in marine fish production. 58 TABLE I : Details of Slate-IVise marine fish catch. Marine fish yield during the period Percen t. States 1962-1975 (in tonnes) age in - - - -- --- -~ to tal Maximum (year) Kerala 4,88 ,269 ( 1973) Maha-rashtra Tamil Nadu 2,56,6 19 ( 1975) 2,29,365 (1975) Gujarat 1,93,775 ( 1975) Andhra Pradesh 1,58,8 18 ( 1974) Karna-taka Goa W. Ben-gal & Orissa Laksha-d"eep 1,16,936 ( 1970) 39,980 (19 71 ) 45,76 1 (1975) 2,931 (1975) Andaman s 1.104 ( 1975) All Maximum Average all Ind ia (year) catch 1,92,4:0 3,44,788 (1962) 1,23,9 16 ( 1968) 1,06,029 ( 1965) 1,69,377 1,56,922 75,633 1,00,444 (1 967) 60,521 88.692 (1962) 39,1 76 ( 1963) 12,460 ( 1967) 8,387 ( 1962) 79 ( 1964) 148 ( 1964) 78 ,851 20,336 1.115 493 35.0 17.2 15.9 10.2 9.0 8.0 24 2.1 0.1 0.1 India 14,22,693 6,44,244 9,84,287 100 (1975) (1962) a) All India marine fish production The annual marine fish catch during 1962-1975 ranged from 644,244 tonnes Seafood Export Journ (1962) to 1,422,693 tonnes (1975), with an average of 984,160 tonnes. Inaia ranked seventh in the world's fish producing countries, the first six countries being Peru , Japan, USSR, Norway, U. S. A. and Chile. India's contribution is about 40 % of the marine fish production of all the countries in the Indian Ocea n region . Fishing at present is mainly confined to the coastal waters upto 50m depth. Along the south-west coast of India, fishing has been extended of late to grounds upto about 450m for perches, deep-water lobs-ters, prawns and other demersal. fishes. The major group or species of pelagic fish along the Ind ian coasts consist of oil sa.rdinel lesse r sa rd ines, Ch irocentrus spp., HI/sa SPP., Anchovielln spp ., Trissocles spp ., other clupeids, mackerel. seerfishes, tunnies, Bombay duck, half beaks, gar fishes, flying f ishes, I ibbon fishes, carangids, Spiryraena spp. , and Mug i/ spp. Demersal f'shes of importance comprise elasmobranchs, eels, cat fishes, perches, I izard fishes, red mullets, polynemids, sciaenids, silver bellies, LacIQ-rius, pomfrets, sales, prawns, other crusta-uans, and cephalopods. In Lakshadweep, the bulk of the catch consists of tunas, particularly the sk ipjack. Perches and .. chavies form the major fishery in Anda-Man Islands. The total catch along the west coast shows considerable annual and seasonal ftuctuations. Although there has been a steep dec I ine in the total catch due to the bilure of oil sardine and mackerel fishelies . ring 1971 and 1974, an overall increase from 1962 to 1975 is not iceable. Along the january, 1918 east coast. a general increasing tr~ nd is noticeable except for minor decline in 1965, 1969, 1971 and 1974, The average catch for the west coast is about 75 % of the total all India landings, w hi le it is only 25 % for the east coast. Multiple species fishery such as those of oil sardine , mac-kerel and Bomhay duck contribute to the major fisheries of the west coast. Among the maritime states Kerala ranks filst in the total marine fish product-ion in the country (35%) followed by Maha-rashtra (17.2% ) , Tamil Nadu (15.2 %), Gujarat 10,2%), Andhra Pradesh (9 %) .. Karnataka (8 %), Goa (2.4% ) and West Bengal and Orissa (2.1 % ). The Un ion terri-tories of Andamans and Lakshadw eep con-tribute less Ihan 0.2 percent. The average catch data for the period 1962- 1975 indi-cate that the best fishing season for the country as a whole is during the fou rth quarter viz., October to December when all the maritime States of the wesl coast of India record higher landings. For Maha-rashtra and Gujalat , the peliod July to Septembe'r (3rd quarter ) and for Kerala and Karnalaka the pe riod April to June (2nd quarler) show relatively poor landings. On the east coast the period of higher land ings va ry from slale to state. In West Benga I and Orissa , Ihe peak fishing period is during OClober to December (4th quarter) while in Andhra Pradesh and Tamil Nadu it is from January to March (1 st quarter). Fishing is relatively poor in these two States during the period April to June (2nd quarter) . 53 b) Variety wise abundance The first five categor ies whose land-ings are over 40,000 tonnes are th e oil sardines, Bombay duck, crustaceans (chiefly the penaeid and non·pena eid prawns), mac-kerel and elasmobranchs. The land ings of other sardi nes, r ibbon fishes, cat fishes, sc iaen ids, Anchoviella spp ., cara ng ids , other clupeiform fishes, Leiagn.,hus and pomfrets are between 20 an d 40 thousand tonnes. i) Pelagic Fishery The landings of mackerel , oil sardine and Bombay duck which are the most im-portant fisheri es on the west coast are given in Table 2. It is evi dent that the TABLE 2 : Total all lndia catch of Mackerel, Oil Sardine and Bombay Duck fo r t" e period 1962-1975 (in tOIll/es) Mackerel Oil Sardine Bombay Duck 1962 29,103 1,10,299 83,934 1963 76,980 63,647 91 ,853 1964 23,863 2,74,333 81,342 1965 43,095 2,61 ,863 73,894 1966 31 ,959 2,47,214 77,363 1967 29,445 2,56,326 74,942 1968 21 ,703 3,01,641 82,501 1969 91 ,837 1,74,249 76 ,276 1970 1,37,607 2,26,984 78,443 1971 2,04,575 2,09,261 71.508 1972 1,08,971 1 ,27,568 51 ,570 1973 79,423 1,44.395 64,345 1974 37,462 1,26,676 61,138 1975 45,947 1,59,240 99,614 Ave rage 68,712 1,91 ,693 76,337 54 la ndings of pelagic fi shes along th e west coast of India, parti cu larl y during the last few yea rs show wide fl uctuations. The decline in the fishery for Bombay duck in Gujarat (1972 -1974) and the partial failure in the mackerel and oil sardine fishery in some years along the Kerala , Karnataka and Goa coasts have been mainly responsible for this. An all time high catch of mackerel of about two lakh tonnes was recorded along Kerala, Karnataka and Goa coasts duri ng 1971, but the catch fell to 37,462 tonnes in 1974 and 45,947 tonnes in 1975, The oil sardine catch during 1968 which w as an all time high record of 3.02 lakh tonnesdeclined to 1.271akh tonnes in 1972. Subsequently, it has showed some increase in 1975 (159,240 tonnes). The annual catch of oi l sardine for 1962- 1975 period was 191,692 metric tons. The lowest catch of 63 ,647 tonnes was in 1964 and the highest catch of 3,01 ,641 tonnes in 1968 formed about 31 .9% of the total catch that year. It may be seen that the annual flu,#ations in the catches of no other species of com-merc ial fish are so marked as those of oil sardine. When the fi shery is good, it forms about a third of the marine fish catch of the cou ntry. The fisheries for sardine are important in two maritime States, Kerala and Karnataka. It is seen that Kerala's oil sa rdine catch is about a half of the ma,ine fish catch of the State and it is about 8 t imes the catch of the oil sardine in Karnataka. The unique position of Kerala in t he oil sardine fi shery of India is abund· ant ly cle ar from the above. Oil satdine occurs in abundance sup· porting a good fi shery from Quilon in the south to Ratn agiri in the north. Beyond Seafood Export Journ northern border of Karnataka, the catches dwindle. In Tamil Nadu and Andhra I'radesh only stray catches are met with. both the States. Kerala and Karnataka, landings in the fourth quarter are the ighest , in the first quarter moderate and .. the third and second quarters poor. The lishe ry commences on the west coast alter B ig sized fishes advanced stages of maturity along with anall sized sardi nes appear in August-October. In the peak fishing season from September to January the catches consist dliefly of juveniles ranging from 12 to 15 an., the fishery gradually decreases and is dosed by about April. The annual average of the mackerel ding"n Ind i a during 1962-1975 was _,712 tonnes. The lowest catch of 21 ,703 IOnnes was in 1968, and the highst catch .. 204,575 was in 1971. Unl ike the oil sardine fishery which is confined to the _st coast, the mackerel is found on both tile coasts. although the bulk of the land-ings to the extent of about 80% are on the _st coast. The annual average landings uve been highest in Karnata. in October-November. However. in Karwar and South lanara two peaks are noticed, one at the Ioeginning and the other at the end of the rlShing season. The macke rel landings are ighest in the fourth quarter and moderate in the first quarter and poor in the second Ira, Karnataka and Kerala States. In Tamil adu, the third quarter's catches are the Ilighest and the fourth quarter' s the lowest. In Andhra, the catches are un iformly IIIOderate in all the quarters except in the january, 1978 third quarter when they are lowest . Mackerel fishery is confined to the inshore regions, but small numbers are occasionally obtained f rom deeper waters off the coasts of Bombay and Saurashtra. Hardly anything is known about the pelagic fishery resources of the north-west coast and the east coast. Available infor-mation indicates the occurrence of mack-erel , sardine, lesser sardines, anchovies and other important groups of pelagic fishes from these areas also. Epipelag ic and mesopelagic fishes such as Myctoph idae and oceanic squids also are found in quantities in these areas. Planned explo-ratory surveys in these areas are essential to assess the pelagic fisheries potential. iii) Demersal fishery The landings of demersal fishes, parti-cularly penaeid and non-penaeid prawns, sciaenids, silver bellies and pomfrets showed an increase during the period 1968- 1975, though in 1974 there is a marginal decline in most of the demersal fisheries. The major factor contributing to the slight but steady increase in demer-sal fish catch for the country as a whole from 1968 to 1975 is the marked increase in the total catch of marine fish for Maha-rashtra during the above period consequent on the steep increase in the catch of prawns there. The crustaceans have formed about 11 % of the total marine fish catches of India in the annual average landings. Prawns are caught in all the maritime States of India, and the landings (based on the average for 1970-1975) show that Maharashtra leads with a catch of 82,328 tonnes followed by Kerala with 55,210 ss tonnes and Andhra Pradesh with a catch of 8,982 tonnes. As regards seasonal trends, in Gujarat and Maharashtra crustacean catches are the highest in rhe second quarter and lowest in the third quarter, in the first and fourth quarters the landings are fairly high. In Kerala , the catches are moderate in the second and fourth quarters and poor in the first quarter. In Tamil Nadu, although the fourth quarter, catches are the lowest, there is no significant variation from quarter to quarter. Trawl ing is almost exclusively carried out for prawns on account of the export market. The overall anticipated increase in the demersal catch of the country is to some extent effected by the increased effort in only limited grounds and the lesser exploitation of other demersal resources. The economic feasi-bility of operating larger fishing vessels in offshore and distant grounds have to be investigated with a view to diversification in fishing. This is especially important for the shelf waters of Maharashtra and Gujarat as well as along most parts of the east coast. It is evident from the above that the landings of fishes, both demersal and pelagic have shown large fluctuations. The existing fisheries are seasonal , the season being clearly demearcated by the two monsoons. In some years very large shoals of fish are found in coastal waters, while in other years no such large scale incurrsion to the coastal waters Occurs. It is not 56 known whether the violent fluctuations were the refections of the stock potential or merely chang9s in distribution and ava ilability owing to variations in the environmental conditions. It is difficult for the industry for planned exploitation of the resources in the absence of this information. A definite knowledge of the resources position and its availability is essential to decide on the type and number of fishing vessels to be operated, the nature and exten t of the shore facilities to be establ ished, the methodologies for the handl ing, processing and distribution of the catches and the magnitude of the investments required. There are good pelagic fishery resources constituted chiefly by the sardines and mackerel and also a fair abundance of demersal fishery resources constituted by a variety of ground fishes, prawns and other crustaceans. The pot"tial of the resources is believed to be much greater than the present production. Explorat,nrv. and scientific expeditions in recent yea have furnished valuable information on available resources along our coasts an also to some extent on the environ men factors determining the fluctuations in important zonal assessments of resources have methods in f ishe ries. Quant the potential fishe been valuable information on the possibil ities large scale fishing. These will be in he subsequent parts of this series. Seafood Export Pesticide and Heavy metal pollution" Polluted air! Poiluted w ater! Po lluted _rth ! Experts worldwide a re be ing fright-~ with the grow ing pro blem of pollution. and technicians endea vour to the problem of planetary contamina-before it reaches the po int of no Can we keep quiet when our en-I l.oolments are dying? To-day it is practi-ally imposs ible to maintain absolutely clean air and pristine pure water. However _ may control the entry of pollutants into . t_,sy,stems to a tolerable level , Only re-1 .",lly we have become aware of the fact we are exceeding nature's ability and c.p;icity to reprocess the kinds and qual ities .. wastes which are being produced. Wostrial Pollutiou Industrial wastes often contain the _ tal components like copper, mercury, " c, arsenic, nickel , lead etc. In the early 1950's, fishermen and their families around .inamata Bay (Japan) were stricken with • mysterious neurological illness. The uary, 1978 A. K. Kumaraguru, T . Lingaraja & V. K. Veougopalao Centre of Advanced Study and Research in Marine Biology. Porto Novo 608 502. M inamata disease, as it came to be called, caused progressive weakening of the mus-cles, loss of vision , impairment of other cerebral function, eventual paralysis and in some cases Coma and death. It caused structu ral injury to the brain. People soon observed that Minamata sea birds and househo ld Cats, w hich like the fisherfo Ik subsist mainly on fish , showed signs of the same disease. Th is led to the discovery of high concentrations of mercury compounds in fish and shell fish taken from the .Bay and the source of mercury was traced to the elfluen.! fmm a factory, Since then there have been several other alarming. incidents. In 1956 and 1960 outbreaks of mercu-rial poisoning involving hundreds of per-sons took place in Iraq, where farmers whe> had received grain seeds, treated witt-. mercurial fungic ids ate them instead of sowing them. There were similar outbreaks later in Pe k istan and Gau tema la. I", Sweden, mortalities of game birds and! other wild life, which fed on mercury 57 

Our fisheries resources and the role of upwelling in their fluctuations Part I marine fish production of India

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Our fisheries resources and the role of upwelling in their fluctuations Part I marine fish production of India

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