LOEB and ROJAS: ICHTHYOPLANKTON COMPOSITION AND ABUNDANCE 



surface temperature (°C) and salinity (%o) values during July-September 

 available Hydrographic "condition" descriptions for these penods are from Robles et al. 



Table 10. — Correlations of across-year abundance ranks of larval 

 fish species groups and member species with ranked (high to low) 

 mean temperature and salinity values from nine July-September 

 sampling periods, 1964-83. Correlations based on Spearman's 

 rho tests. Group correlations based on ranks of summed within- 

 year ranks of member species. Significant values at P < 0.05 are 

 indicated but note use of multiple testing. " = abundance ranks 

 adjusted to accommodate for apparent large sampling depth- 

 related catch differences. 



abundances during colder, lower salinity periods. 

 The rankings of Group I (based on ranks of 

 summed within-year member species ranks) are 

 significantly correlated (P < 0.05) with both 

 temperature and salinity (p = -0.78 in both 

 cases). Within this group the rankings of 

 Normanichthys crockeri and Blenniid D are cor- 

 related (P < 0.05) with temperature and salinity 

 (p = -0.69 to -0.77); the correlation of Sebastes 

 with temperature is also relatively strong 

 (p = -0.67). Within Species Pair II, Lampanyctus 

 parvicauda abundance has a relatively strong 



negative correlation with temperature (p = 

 -0.68). 



Group II and Pair I and their member species 

 have positive correlations of ranked abundance 

 with temperature and (with one exception) salin- 

 ity values (Table 10) suggesting a tendency for 

 higher abundances during warmer, higher salin- 

 ity conditions. These correlations are all non- 

 significant and generally weak for Group II and 

 its member species (Bathylagus nigrigenys , Vin- 

 ciguerria lucetia, and Diogenichthys laternatus). 

 Pair I has a positive correlation (P < 0.05) with 

 temperature (p = +0.70) primarily due to sardine 

 abundance ranks. 



Species Percentage Composition 

 Relative to Hydrographic Conditions 



Ichthyoplankton percentage composition shows 

 no striking warm year vs. cold year related 

 patterns. Total ichthyoplankton composition 

 comparisons between years of "similar" hydro- 

 graphic conditions do not give overall higher PSI 

 values than do comparisons between years of dif- 

 ferent conditions (Table llA). PSI values (ranges, 

 means, and proportions of high and moderate val- 

 ues) from comparisons of cold, transition, and 

 warm years are similar. However, highest values 

 (91.6-94.9) come from cold vs. transition year 

 (1970 vs. 1966 and 1973) and between-transition 

 year (1966 vs. 1973) comparisons. Additionally, 

 intercomparisons of the transition, warm, and 

 El Niilo years give relatively lower values than 

 do cold-year comparisons. Comparisons between 

 El Nino years give generally PSI low values. 



15 



