Vol. 53 - Alaska Resources Library and Information Services

Larval crangonids, Crangon spp., were consistently found in greater
abundance over the St. George Basin of the outer shelf domain in a band
west of the 100 m isobath.
Figures 6.27-6.30 depict the larval distribution
and abundance of Crangon spp. from PROBES and NOAA cruises from
1976 to 1981. While the crangonids were almost as wide ranging as the
hippolytids, they were generally absent beyond the shelf break and most
prevalent over the inner shelf domain (less than 50 m).
The two high
density (> 1000 larvae/100 m 2 ) stations in the inner shelf domain (Fig.
6.27) were due to a different species than found at the high density
stations over the St. George Basin.
Figure 6.28 gives the distribution
of Crangon spp. larvae during April and May of 1976 and 1977 (NOAA).
Greatest larval densities were found in the outer shelf domain of the
St. George Basin midway between the 100 and 200 m isobaths and also off
Akutan and Unalaska Islands.
Monthly variation in density is illustrated by comparing Figs. 6.29
for April and 6.30 for May and June PROBES 1978. By April in 1978,
Crangon spp. were distributed at fairly low densities throughout the St.
George Basin and infrequently over the southern half of the mid-shelf
domain.
By May and June, larvae were concentrated in a band along the
100 m isobath at slightly higher densities than found in April (Fig.
6.30). This is somewhat different from the pattern seen in 1981 when
sampling effort concentrated on the PROBES A line and distribution by
May and June was extensive over the middle shelf domain (Fig. 6.27).
Monthly variation is also illustrated by Figure 6.31 that depicts Crangon
spp. larval mean densities in stratum 2 by month and by year.
Mean
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