Wm. Hamner et al., SUN COMPASS MIGRATION BY AURELIA-AURITA (SCYPHOZOA) - POPULATION RETENTION AND REPRODUCTION IN SAANICH INLET, BRITISH-COLUMBIA, Marine Biology, 119(3), 1994, pp. 347-356
The scyphomedusa Aurelia aurita in Saanich Inlet, a north-south orient
ed fjord in British Columbia, uses a sun compass to migrate in a south
easterly direction during the day. When the sky is overcast and at nig
ht, A. aurita orients randomly and is dispersed passively by gentle ti
dal currents. The net result is daily reaggregation of medusae into en
ormous swarms along the southeastern shore of the fjord. Observations
of spawning A. aurita in these swarms suggest that sun-compass migrati
on and aggregative behavior may have evolved to facilitate reproductio
n and to maintain the population within this fjord throughout the year
.