Abstract:
The ability of Cumella vulgaris to avoid burial under different
rates of sedimentation and to recover from burial once buried was
studied. Sedimentation rates higher than 0. 25 cm/mm are
necessary to bury 50% of C. vulgaris with the deposition of 4 cm of
sediment.
Cumella vulgaris can swim several times faster than the
sedimentation rates at which fine sand successfully buried
it. Immatures and females swam at speeds of 0.25-1.5 cm/sec;
males swam at speeds up to 5 cm/sec. Sinking speeds of live C.
vulgaris were proportional to size and varied from 0.2-1.6 cm/sec.
Cumella vulgaris should be able to avoid burial by dredging caused
sedimentation. Dredging's most important impact on this
species would most likely be long term changes in a bay which
might reduce its habitat.
Dead C. vulgaris were buried in their habitat in winter.
Four days later one-half were successfully recovered by coring.
When doing field studies of the acute effects of dredging on a
habitat one needs to be aware that victims of burial may be recoverable
for several days after death and may need to be distinguished from living animals.
