SS1.09 Fisheries Population Linkage Spatial and Temporal Variation in Zooplankton
Date: Wednesday, June 12, 2002
Time: 4:30:00 PM
Location: Carson C
 
CurtisKA, Scripps Institution of Oceanography, La Jolla, CA, USA, kcurtis@ucsd.edu
 
SMALL-SCALE SPATIAL PATTERN OF SARDINE AND ANCHOVY EGGS: INTERSPECIFIC VARIATION IN SPAWNING BEHAVIOR?
image
The horizontal spatial patterns of Pacific sardine (Sardinops sagax) and northern anchovy (Engraulis mordax) eggs show different characteristics on the scale of 0.75 to 2.5 km. Sardine and anchovy eggs were collected at 4-minute intervals with a Continuous Underway Fish Egg Sampler while steaming grids that measured roughly 5 km to a side. Variograms calculated for staged sardine egg samples have a very low nugget effect on the order of 10% (values are strongly correlated on the smallest scales) and the semivariance increases approximately linearly across the scales sampled. In contrast, anchovy egg variograms have a very high nugget effect ranging from 50% to 100%, so the majority of the total variance is random noise at the scales sampled. These differences in observed spatial structure of the eggs likely reflect differences in the sizes and structures of the adult spawning groups.