CalCOFI Reports, Vol. 11, 1967 - California Cooperative Oceanic ...
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CalCOFI Reports, Vol. 11, 1967 - California Cooperative Oceanic ...

CalCOFI Reports, Vol. 11, 1967 - California Cooperative Oceanic ... CalCOFI Reports, Vol. 11, 1967 - California Cooperative Oceanic ...

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~i:i46 CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONSfnzw5U0cnnz2 20030II-I-0-0-SIRASU1910 1920 1930 1940 1950 1960 YEARFIGURE 2. Annual landings of the anchovy (190562) and sirasu (1949, 1950 and 195362). Data for 1905-25 and far 195162 from Statistics andSurvey Division, MAF (1906-26 and 1952-63), those for 1926-31 and for 1933-48 from Kurita and Tanaka (1956), those far 1932 from Statirticsand Survey Division, MAF (1933) and Takayama and Sakai (1936), those for 1949 and 1950 from unpublished record taken by Takai RegionalFisheries Research Laboratory. The figure for 1941 is corrected according to Nakai (1960).TABLE 2ANCHOVY AND SIRASU CATCH BY METHOD OF FISHING INJAPAN, 1962.UNIT: 1,000 METRIC TONS%349.5 (100.0 ) 26.3ISubtotal---- 203.2 ( 58.1 ) 0.1Two-boatpurse seine. 157.8 ( 45.2 ) 0.0Others ___.. 45.4 ( 13.0 ) 0.0Lift nets _.__....______..._..18.2 ( 5.2 ) 2.2Total _ __________________Set nets- .._..._..........__ 9.6 ( 2.8 ) 0.0I/Subtotal._.- 102.8 ( 29.1 ) 21.5Boat seinegroup-- ._...__ Patti-amL-. 54.2 ( 15.5 ) 0.4Boatseine.- 48.7 ( 13.9 ) 15.1Beach seine- _._________...._.14.8 ( 4.2 ) 2.5Other methods ._..._.___..... 1.7 ( 0.5 ) 0.0Anchovy 1 sirasu14 em in body length are scarce in the commercialcatch. All the sizes appear in both Pacific and JapanSea sides. Generally, the length composition datashow three modes, (i) postlarvae around 25 mmmainly caught by boat seine, (ii) immature around6-8 cm in body length by patti-ami and (iii) adultsover 10 em in body length by two-boat purse seines.It is also noted that the mean length is usually largerin the northern areas than in the southern areas(Yokota and Asami 1956, Yamanaka and Ito 1957,Hayasi 1961, Ex. Com., Conf. Invest. Neritic-PelagicFisher. Japan 1961-63, Asami 1962, Takao 1964).A REMARK ON THE COOPERATIVEINVESTIGATIONSThe life history of the Japanese anchovy has notbeen investigated thoroughly enough to promote advancein the studies for forecasting and assessing thepopulation up to the early 1950 's. Since the cooperativeinvestigations started in 1949, the biological informationof the fish, including the amount and compositionof the commercial catch, the number of eggsand larvae in the sea, and the environmental condi-

REPORTS VOLUSIE SI, 1 JULY 1963 TO 30 JUSE 1966 47tions have been collected through systematic surveys,which almost all fisheries experimental stations ofprefectural governments facing on the sea and theseven regional fisheries research laboratories haveengaged in. Another investigation program was startedin 1964 with the aim of forecasting fish stocks, inclusiveof anchovy, as well as oceanographic conditions.As far as the neritic-pelagic fishes are concerned,these two investigation programs are conducted asalmost one project. The following description covers(i) social demands on the fishery research agencies.(ii) development of methodology and (iii) scale ofthe investigations.At the start of the cooperative investigations, majorefforts were laid upon the sardine, the decrease ofwhich caused serious economic and social problemsin Japan (Nakai et al. 1955). Since the middle 1950 's,anchovies have exceeded sardines in amount of thecommercial catch and more extensive information hasbeen necessitated for predicting and regulating theanchovy stock to increase the economic productivityof fisheries, especially the two-boat purse seine andthe boat seines on the Pacific waters along Honsyu,Sikoku and Kyusyu, and on the Set0 Inland Sea.At the initial stage of the cooperative investigations,the most urgent project was to collect informationon the life history of the species in order to advancethe study of population dynamics (Hayasi1961). However, the biological information thus collectedhas lead many fishery biologists to think thatthe numerical analysis of the fish populations showsonly limited aspects of nature (for instance, Tanaka1960, Hayasi 1961, Nakai (1962b). An alternativemethodology, in which a species is treated as amember of the community (Yokota and Asami 1956,Yokota et al. 1962), is regarded fruitless unless theelemental species are sufficiently understood. Recently,Sat0 (1961, 1964) proposed a methodology of fisherybiology, through investigations of the king crab, Paralithodescamtschaticus (Tilesius) , which necessitatesthe logical system of scientific conceptions. A moredetailed explanation of his proposal is given in thefollowing sections.During April 1949 through March 1950 the cooperativeinvestigations covered collection of catch statistics,surveys on the age and length composition andmorphometric characters of the commercial catch,and the distribution and abundance of eggs and larvaeas well as oceanographic conditions. The morphometriccharacters surveyed were body length, body weight,sex, gonad weight, diameter of ova, stomach contents,vertebral counts and scale rings. The eggs and larvaewere collected by standardized nets (Nakai 1962a).Engaged in the investigations during the first yearwere 47 prefectural fisheries experimental stations and68 research boats of 34 prefectures, five regionalfisheries research laboratories and four research vesselsof the Fisheries Agency. Consequently, eggs andlarvae were collected at 5,035 observatory stations(Nakai and Hattori 1962) , and morphometric characterswere determined for 14,202 anchovies taken at82 landing ports (Nakai et al. 1955). Since 1951, moreefforts have been laid on the length composition surveyin order to improve the accuracy of the estimates ofpopulation characteristics (Nakai et al. 1955). Forthe later years, almost the same amount of data havebeen collected annually. In addition, daily reportshave been taken from some of purse seiners operatingon major fishing grounds (Hirakawa 1955, Ex. Com.,Conf. Invest. Neritic-Pelagic Fisher. Japan 1961-63).Since 1964, the boat survey has been conductedroutinely, and the number of regular oceanographicstations has been increased as much as twice that inthe preceding years.BI 0 LOGICAL INFO RMATlO NIt is axiomatic that fishery biologists working onany project attempt to approach not only the aspectof their interest but also the mechanisms regulatingbiological production of the organisms. For instance,a biologist researches the growth of the fish in orderto determine how the species population changes insize, distribution or migratory route in the naturalwaters. Unless the position and role of any researchproject are subjectively determined, however, the investigationsmay not indicate the true nature of theorganisms, because all the aspects are unified in thereal life of organisms, which essentially changes fromstep to step during the course of ontogenesis. Thismakes it necessary to consider methods to systematizebiological information on any species.In the course of fishery biology, most phenomena areobserved through the commercial fisheries. This factmeans that one can see only compounds of three factors,fishes and environments in nature, and productivepower of the human society. Accordingly, it isnecessary to establish three systems of sciences correspondingto these factors. In the case of the anchovyinvestigations, the scientific systems are (i) biology,especially ecology, (ii) oceanography, and (iii) technologyand economics. The biological features of theanchovy will be described subjectively with the useof categories particular to biology, which must bedrawn on the bases of the following three features oforganisms.First, the living resources are retained and developthrough their two major functions, individual maintenanceand species maintenance, that are resultsof interactions between organisms. This fact showsthat the species is the most comprehensive categoryin biology.Second, the species has differentiated in the courseof evolution. This fact makes the species and the subspeciestwo conceptions mutually defining one another(Darwin 1917). Eventually, it is concluded that a,species population comprises subspecies that haveboth universality of the species and peculiarity ofthe subspecies. Systematic fractions of a species population,e.g. subpopulation defined by Marr (1957) ,must comprise the same nature. Therefore, the systematicfraction is to be considered as one of the majorcategories, being defined on the basis of the substantialknowledge of life of the species population.Third, form and function of an individual essentiallychange depending upon the developmental

~i:i46 CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONSfnzw5U0cnnz2 20030II-I-0-0-SIRASU1910 1920 1930 1940 1950 1960 YEARFIGURE 2. Annual landings of the anchovy (190562) and sirasu (1949, 1950 and 195362). Data for 1905-25 and far 195162 from Statistics andSurvey Division, MAF (1906-26 and 1952-63), those for 1926-31 and for 1933-48 from Kurita and Tanaka (1956), those far 1932 from Statirticsand Survey Division, MAF (1933) and Takayama and Sakai (1936), those for 1949 and 1950 from unpublished record taken by Takai RegionalFisheries Research Laboratory. The figure for 1941 is corrected according to Nakai (1960).TABLE 2ANCHOVY AND SIRASU CATCH BY METHOD OF FISHING INJAPAN, 1962.UNIT: 1,000 METRIC TONS%349.5 (100.0 ) 26.3ISubtotal---- 203.2 ( 58.1 ) 0.1Two-boatpurse seine. 157.8 ( 45.2 ) 0.0Others ___.. 45.4 ( 13.0 ) 0.0Lift nets _.__....______..._..18.2 ( 5.2 ) 2.2Total _ __________________Set nets- .._..._..........__ 9.6 ( 2.8 ) 0.0I/Subtotal._.- 102.8 ( 29.1 ) 21.5Boat seinegroup-- ._...__ Patti-amL-. 54.2 ( 15.5 ) 0.4Boatseine.- 48.7 ( 13.9 ) 15.1Beach seine- _._________...._.14.8 ( 4.2 ) 2.5Other methods ._..._.___..... 1.7 ( 0.5 ) 0.0Anchovy 1 sirasu14 em in body length are scarce in the commercialcatch. All the sizes appear in both Pacific and JapanSea sides. Generally, the length composition datashow three modes, (i) postlarvae around 25 mmmainly caught by boat seine, (ii) immature around6-8 cm in body length by patti-ami and (iii) adultsover 10 em in body length by two-boat purse seines.It is also noted that the mean length is usually largerin the northern areas than in the southern areas(Yokota and Asami 1956, Yamanaka and Ito 1957,Hayasi 1961, Ex. Com., Conf. Invest. Neritic-PelagicFisher. Japan 1961-63, Asami 1962, Takao 1964).A REMARK ON THE COOPERATIVEINVESTIGATIONSThe life history of the Japanese anchovy has notbeen investigated thoroughly enough to promote advancein the studies for forecasting and assessing thepopulation up to the early 1950 's. Since the cooperativeinvestigations started in 1949, the biological informationof the fish, including the amount and compositionof the commercial catch, the number of eggsand larvae in the sea, and the environmental condi-

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