Vol. 53 - Alaska Resources Library and Information Services

are reported in detail by Incze (1983).
The description by Jewett and
Haight (1977) was used to distinguish megalops larvae of the two
species.
4.5 Results and Discussion
4.5.1 Timing of Hatchout
The timing of initial hatchout of larvae of the two species was
examined by plotting against time the mean larval densities (number/
1000m³) estimated from samples collected during April and May of 1977,
1978, 1980, and 1981. Because crab larvae were relatively rare during
these months, plankton samples were searched completely, not sub-sampled.
The following criteria were used to select stations with data adequate
for this analysis:
1) if a sample from a station contained larvae, the
estimated abundance at that station was recorded for the corresponding
date; 2) if a sample did not contain larvae but subsequent occupation of
the sampling area (within a radius of approximately 27.8 km, 15 NM)
showed that there were eventually larvae there, the "zero" abundance was
recorded for the earlier date; 3) if a sampling location did not contain
larvae and was not occupied again later, or was occupied and continued
to show no larvae, the "zero" datum was not entered into the analysis.
In this way, the period before any detectable hatchout occurred could be
identified without risk of biasing the analysis with data from sample
locations not yielding zoeae of that species in that year. Sample
coverage in the study area was not sufficient during any one year to
enable a statistical comparison of initial hatchout times for different
sub-areas (eg. middle shelf vs. outer shelf).
Consequently, the data
607