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

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108 CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONSbution was rather uniform along the coast betweenlat. 8' S. and lat. 14" S. (Table 2). At both ends o€the distributional range lower numbers are encoun-The marked changes that have occurred in thepopulation size of the guano birds during the period1955 to 1963, are shown in Figure 3. The increasedTABLE 2NUMBER OF GUANO BIRDS, IN THOUSANDS, IN THE COASTALAREAS OF PERU, ACCORDING TO AREAS OF TWO LATITUDINALDEGREESSouth LatitudeIYearl I I I I 1962 -1 1,141 1 2,027 1 3,700 1 5,539 1 4,309 I 2966' to So So to 10' 10" to 12O 12' to 14" 14' to 16' 16' to 18'- ~ ~ - ~ _ _ _ _ ~1963 - 1,603 3,840 4,719 2,813 4,749 350South LatitudeYear 6' to 8' 1 8' to 10' I 10' to 12' I 12" to 14" I 14' to 16" I 16' to 18O1 I <strong>11</strong>962 - 2,501.8 1,446.3 2,045.5 274.21,816.3 2,031.41 1 19634 1: 2,155.9 1: 419.5Two main centers of landing stand out: Chimbote(lat. 9" S.) and Callao (lat. 12" S.), which togetheraccount for about 50% of the total catch landed inPeru. Intermediate centers are developing rapidlyas is also the area between lat. 12" S. and lat. 14" S.(Tambo de Mora and Pisco). Thus it will be seenthat fishermen and birds exploit and exert heavypressure on the anchovy stock in the whole areabetween lat. 8" S. and lat. 14" S.There are some very densely populated bird centers,such as La Vieja Island (lat. 14" 17' S.) and theheadland Punta Culebras (lat. 9' 57' S.), each ofwhich is temporarily inhabited by about 3 millionadult birds, which means that they have to fishabout 1,200 tons of anchovy per day for their sustenance.It was found possible to estimate roughly thegreat changes that have occurred in the populationsize during the last 54 years, using the annualharvesting of guano as a basis. Decreases during certainyears coincide with changes in the oceanic climateof the Peruvian current. It has been shown(JordBn and Fuentes 1964) that during these abnormalyears, the availability of the anchovy for thebirds was greatly diminished, which resulted in thebreak-up of colonies and heavy mortalities.FIGURE 3. The population size of the guano birds and anchovy landingsduring 1955 to 1964.anchovy catches by the fishing fleet during the sameperiod are also shown.The population estimate for 1955 (28 million birds)represents the highest peak ever reached duringthe last 54 years. During this year the birds mayhave taken some 4 million tons of anchovy out of thesea, while fishing was still at a low level.After the great fall in bird numbers that occurredduring 1957 and 1958, a steady increase was noteduntil the beginning of 1963, occurring simultaneouslywith an enormous increase in the yields of the fishery,which reached about 6 million tons in 1962. Duringthis year the birds extracted some 3 million tons ofanchovy out of the sea. A new wave of bird mortalitiesoccurred in the autumn and winter of 1963(June to September) , which reduced the populationsize considerably at the end. The fishery caught 8.8million tons of anchovy, apparently without havingcaused food shortages for the birds.The future of the guano industry and the fishingindustry is entirely dependent on the anchovy resource.From our study of the fluctuations in thepopulation size of the guano birds it can be inferredthat the anchovy stock is vulnerable when subjectedto marked changes in the oceanic climate. A tooheavy predation under such circumstances may havefar reaching consequences for the delicate balance
REPORTS VOLUME XI, 1 JULY 1963 TO 30 JUNE 1966109existing in the autonomous regime of the fauna ofPeru current.REFERENCESAvila, E. 1954. Potencia deyectiva de Guanay (Ph. bougainvil-Zii) . Cia. Admora. Guano, BoE. Cient., 1 (2) :22-49.Barreda, 0. &I. 1959. Recuperacidn de guanayes (Ph. bougaincil-Ui) caquikticos en cautividad.-Estudio de su ingestidn ydeyeccidn. Cia. Admora. Guano, BoZ. 35(4) :lo-22.Gamarra, D. L. 1941. RelaciBn entre la cantidad de aliment0iugerido por las aves guaneras y el guano aprovechable queproducen. Cia Admora. Guano, BoZ. 17 :104-<strong>11</strong>.5.Hutchinson, G. E. 1950. Survey of existing knowledge of biogeochemistry.3. The biogeochemistry of vertebrate excretion.Amer. Mus. Nut. Hist., Bull., 96 : 1-554.Jordfin, R. 1959. El fendmeno de las regurgitaciones en elGuanay (Ph. bougainvillii L.) y un metodo para estimar laingestidn diaria. Cia. Admora. Guano, Bol., 35(4) :23-40.-1964. Las emigraciones y mortandad de las aves en el inviernoy otofio de 1963. Inst. Invest. Recurs. Mar., Informes(27):1-44.Jordh, R., and H. Fuentes. 1964. Resultados de 10s censos grsficosde aves guaneras efectuados durante el ciclo reproductivo1962-1963. Inst. Invest. Recurs. Mar., Informes (22):1-15.Vogt, W. 1942. Informe sobre las aves guaneras. Cia Admora.Guano, Bol., 18(3) :1-132.
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STATE OF CALIFORNIAMARINE RESEARCH
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STATE OF CALIFORNIADEPARTMENT OF FI
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RONALD REAGAXGovcriwr of the Slate
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PART 1REVIEW OF ACTIVITIESJuly 1,19
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REPORTS YOLUAIE SI, 1 JULY 1963 TO
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REPORTS VOLUNE XI, 1 JULY 1963 TO 3
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REPORTS YOLUME SI, 1 JULY 1963 TO 3
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REPORTS VOLUME XI, 1 JULY 1963 TO 3
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REPORTS vor,uiwIi; SI, 1 JULY 1063
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REPORTS TOT2T71\IF: SI, 1 JUJIT 196
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IiEPOHTS TOLUME XI, 1 JULY 1963 TO
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REVIEW OF THE PELAGIC WET FISHERIES
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KEI'OiiTH TOLUJIE SI, 1 JULY 1963 T
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PART IISYMPOSIUM ON ANCHOVIES, GENU
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OCEANIC ENVIRONMENTS OF THE GENUS E
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KEI'OKTS VOLIXI.: SI, 1 JULY 1963 T
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~~~REPORTS VOLUME XI, 1 JULY 1963 T
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REPORTS VOLUME SI, 1 JULY 1963 TO 3
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130'E 132' 134' 136' 138' 140' 142-
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REPORTS VOLUSIE SI, 1 JULY 1963 TO
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KI3I’ORTH VOLUJIE XI, 1 JULY 1963
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Page 69 and 70: INFLUENCE OF SOME ENVIRONMENTAL FAC
Page 71 and 72: REPORTS Y‘OLUJIE XI, 1 JULY 1963
Page 75 and 76: ~table shows the values calculated
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Page 79 and 80: REPORTS POLGNE SI, 1 JU LY 1963 TO
Page 81 and 82: REPORTS VOLUXE XI, 1 JULY 1963 TO 3
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Page 87 and 88: REPORTS TOLTIJIE SI, 1 JULY 1963 TO
Page 89 and 90: -20/5-0 10-f 5-w 25-0 20-= 15-: 10-
Page 91 and 92: REPORTS VOLUNE SI. 1 JULY 19G3 TO 3
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Page 107 and 108: THE PREDATION OF GUANO BIRDS ON THE
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Page 115 and 116: FISH E RYThe California anchovy fis
Page 117 and 118: ~~ ::REPORTS VOLUME XI, 1 JULY 1963
Page 119: CO-OCCURRENCES OF SARDINE AND ANCHO
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Page 124 and 125: CALIFORNIA COOPERATIVE OCEANlC FISH
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Page 138 and 139: THE ACCUMULATION OF FISH DEBRIS IN
Page 143 and 144: PART IllSCIENTIFIC CONTRIBUTIONS
Page 151 and 152: REPORTS VOLU&IE XI, 1 JULY 1963 TO
Page 157 and 158: SUMMARY OF THERMAL CONDITIONS AND P
Page 159 and 160: SEASONAL VARIATION OF TEMPERATURE A
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REPORTS VOLUME SI, 1 JULY 1963 TO 3
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including the semiannual harmonic?
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REPORTS VOiLUME XI, 1 JULY 1983 TO
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170 CALIFORNIA COOPERATIVE OCWIC FI
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172 CALIFORNIA COOPERATIVE OCBANIC
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174 CALIFORNIA COOPERATIVE OCEANIC
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184CALIFORNIA COOPERATIVE OCEANIC F
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CONTENTSI. Review of Activities Pag
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