FISHERY BULLETIN: VOL. 81, NO. 2 



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1970 



YEARS 



FIGURE 3.— The Peruvian fishmeal production for 1962-81 and 

 Chilean fishmeal production for 1 974-8 1 in millions of metric tons as 

 obtained from National Marine Fisheries Service (1977, 1979, 1981, 

 1982). 



cases it might have been advantageous to conserve 

 reproductive stocks (ban fishing) in order to mini- 

 mize subsequent recruitment failures. It appears 

 that the operating regulations since the 1976 El 

 Nino, as reported in the introductory section, were 

 initiated much too late to benefit the anchoveta. 



Available information on the fishery off northern 

 Chile, along with the El Nino-related effects on it, is 

 quite limited; nevertheless, contents of the introduc- 

 tory section and the previous section indicate it 

 should be included in this discussion. Over the past 2 

 decades the fisheries off the coast of northern Chile, 

 although not as productive formerly as those off 

 Peru, have been likewise exploited most of this time 

 without regard for conservation of the fish popula- 

 tion. However, we must realize that whereas ancho- 

 veta, as a percentage of the catch, was still at the 95% 

 level in 1973 in the Peruvian fishery (Ceres 1981), it 

 declined from a level of 70-80% of the catch off 

 northern Chile before 1970 to a little over 30% by 

 1973; and after the 1976 El Nino the percentage 

 dropped precipitously to <10% of the northern 

 Chilean catch for 1 9 7 7 , with sardines, jurel, and other 

 fish making up the rest of the catch (figure 4 of 

 Caviedes 1981). This would indicate that the decline 

 in anchoveta, as a percentage of catch, showed up 



several years earlier off the coast of northern Chile 

 than it did off the coast of Peru. Also, the substantial 

 increase in other fish (e.g., jurel, sardines) was noted 

 earlier off northern Chile than was the increase in sar- 

 dines and mackerel off Peru (Ceres 1981; Caviedes 

 1981). It is interesting that Caviedes (1981) reported 

 the largest jurel catches off northern Chile during the 

 El Nino-related years of 1973, 1975, and 1977, the 

 same years that Vondruska (1981) in his table 3 

 showed the combined Peru plus Chile production of 

 fishmeal to be at its lowest levels. 



Since 1976 the SST's over the tropical and sub- 

 tropical southeast Pacific, as evidenced in the Fish- 

 ing Information (National Marine Fisheries Service 

 1976-80) and Forrest Miller's continuation analyses, 

 have remained near or above normal; and sea level 

 pressures in the South Pacific subtropical ridge, as 

 represented by pressures at Easter, Totegegie, and 

 Rapa Islands, have averaged below normal over this 

 same period. An indication that this was taking place 

 was shown earlier in figure 7 of Quinn (1980b). In- 

 stead of having a compensating prolonged rise in the 

 Easter-Darwin index to high positive anomalies 

 following the deep index anomaly trough of the 1976- 

 77 event, as one would ordinarily expect after an El 

 Nino, the index has remained unusually low. It has 

 averaged about 2 mbar below normal over the past 75 

 mo (April 1976-June 1982), and 78% of this abnor- 

 mally low value was caused by the contribution of the 

 Easter Island pressure component. In the past, it was 

 usually during the high index anti-El Nino periods 

 that the Peruvian anchoveta fishery recuperated. 

 During this extended low index period the Peruvian 

 fishmeal production has continued its pattern of 

 decline (Fig. 3) to the extent that Peru has fallen from 

 its position of leading fishmeal producer in the 

 Fishmeal Exporters Organization to a number two 

 position behind Chile for 1980 and 1981. Although 

 Peruvian fishermen modified their efforts so as to 

 also catch the types of fish which have recently 

 become more numerous (e.g., mackerel and sar- 

 dines), this modification was necessitated by the 

 change in composition of the pelagic biomass (which 

 showed a drastic reduction in the anchoveta). As 

 mentioned before, a similar change in biomass with a 

 drastic reduction in anchoveta also occurred in the 

 fisheries off northern Chile, although this change off 

 northern Chile started setting in earlier. How much of 

 the change in fishery composition has been the result 

 of fishing practices (e.g., overfishing) and how much 

 can be attributed to environmental change or other 

 ecological factors is questionable; however, it is our 

 opinion that the recent unusual climatic trend, as 

 represented by the abnormally low Southern Oscilla- 



370 



