A study has been made of the vertical distributions and
migrations of a large number of zooplankton species at Weather
Station "P" in the Subarctic Pacific. Simultaneously towed horizontal
opening-closing nets were used for the study. The distributions
and migrations of 104 taxa have been subjectively grouped
into seven basic...
In the upper estuary of Yaquina Bay, Oregon, there is an annual
population explosion of Acartia tonsa, (Dana) a calanoid copepod,
during the months of July, August and September, followed by a rapid
decline to virtual extinction in November. The restricted estuarine
distribution affords an excellent opportunity to study the...
An attempt has been made to experimentally interbreed Atlantic
and Pacific populations of the marine calanoid copepod Acartia clausi
Giesbrecht. Breeding between individuals from each population produced many successive generations in the laboratory, but interbreeding between populations failed to produce viable offspring. This result
is strong evidence that the Atlantic...