Vol. 53 - Alaska Resources Library and Information Services

3. Most of the larval hatchout occurs over a period of about two weeks
while the total hatchout period may cover 30 or more days.
4. The two zoeal stages last about one month each. The megalops stage
lasts at least one month and perhaps considerably longer. Megalops
larvae have been collected in considerable numbers over the St.
George Basin as late as early October.
5. Eighty-six percent of zoea larvae were found in the upper 20 m of
the water column.
Megalops larvae showed a more variable depth
distribution and were sometimes abundant in the neuston layer.
6. The larvae of C. bairdi were always found in abundance over the St.
George Basin, particularly over shelf depths of 100-150 m. Larvae
of C. opilio were sometimes, but not always, very abundant in this
area.
7. Larval year-class strength of C. opilio fluctuated by almost two
orders of magnitude (difference in abundance) during this study.
"Strong" larval year-classes may be critical to maintenance of C.
opilio stocks at high levels.
8. Larval abundances in excess of 1,000 larvae/100 m 2 sea surface area
are common for both species.
The maximum mean monthly abundance observed
for a single species was 172,124 larvae/100 m² (Stage I zoeae
of C. opilio, stratum 1, April 1978).
Since 86% of zoeae are in
the upper 20 m, these values correspond to estimated densities of
636