FISHERY BULLETIN VOL H6, NO 1 



Table 8. — Range, mean, standard deviation and ranked (high to low) values of sea 

 ichthyoplankton sampling periods, 1964-83. N = number of observations. N.A. ^ data not 

 (1976), Bernal et al. (1982), and Kelly and Blanco (1983). 



September mean temperature and salinity val- 

 ues; larval diversity (mean number of taxa/tow) 

 also shows no correlation with these values 

 (Table 9). Within the PL, anchoveta were most 

 abundant during years immediately following El 

 Nihos (cold 1966, transition 1973), the 1972 El 

 Nirio, and cold 1970; lowest abundances were dur- 

 ing the 1965 and 1983 El Nihos (Table 8). There 

 are no significant correlations between ranked 

 anchoveta abundances and ranked values of tem- 

 perature or salinity (Table 10). Sardine larvae 

 were most abundant during and after the 1972 El 

 Niiio; prior to this moderate abundances and rela- 

 tively large percentage contributions to the 

 ichthyoplankton occurred only during the warm 

 1968-69 period (Tables 5, 7). Lowest sardine 

 abundances were during cold years 1964, 1967, 

 and 1970 and the 1965 El Nino. Despite low abun- 

 dances during the 1965 El Nino, there is a signif- 

 icant positive correlation between ranked sardine 

 abundance and temperature (p = +0.69, P 

 < 0.05). Ranked larval anchoveta and sardine 

 abundances are not correlated (p = -0.07). 



The only apparent warm-cold year abundance 

 pattern among the OL categories is that of the 

 coastal taxa; this group had lowest abundances 

 during the 1965, 1972, and 1983 El Nihos and 

 highest abundances in subsequent 1966 and 1973 

 transition years. The ranked abundance pattern 

 of this category has negative correlations 

 (P < 0.05) with ranked temperature (p = -0.69) 

 and salinity (p = -0.68) values (Table 9). Both 

 the myctophid and other mesopelagic categories 

 appear to have abundance patterns unrelated to 

 warm-cold hydrographic conditions (Table 9). 



Table 9. — Correlations of across-year abundance ranks of 

 zooplankton and ichthyoplankton categories with ranked (high to 

 low) mean temperature and salinity values from nine July-Septem- 

 ber sampling periods off northern Chile, 1964-83. Correlations 

 based on Spearman's rho tests. Significant values at P s 0.05 are 

 indicated, but note use of multiple testing. PL = larvae of pelagic 

 species; OL = other larval taxa. 



Zooplankton biomass values show negative but 

 nonsignificant correlations with temperature and 

 salinity (Table 9). This is in agreement with the 

 time-series analysis results of Bernal et al. (1983) 

 which demonstrated no consistent relations of 

 zooplankton biomass with cold- or warm-water 

 events. 



Species Groups and 

 Hydrographic Conditions 



The species groups formed by similarity of 

 between-year abundance ranks demonstrate both 

 positive and negative correlations with cold- and 

 warm-year conditions (Table 10). Group I and 

 Pair II and their member species have negative 

 correlations with ranked temperature and 

 salinity values indicating a tendency for higher 



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