DISTRIBUTION OF TWO SPECIES OF LAMINARIA AS RELATED TO SOME ENVIRONMENTAL FACTORS(1)

The distributions of Laminaria saccharina and the long and short stipe forms of L. groenlandica about Vancouver Island were correlated with temperature, salinity, and water motion. The 2 forms of L. groenlandica were absent from areas of high temperature and low salinity. The long stipe form was restricted to areas of heavy surf and the short stipe form to areas of moderate surf. L. saccharina was absent from areas subjected to surf. These observations were subjected to laboratory and field tests involving gametophytes and sporophytes of both species. The distributions of the 2 forms of L. groenlandica can be explained on the basis of temperature and salinity distributions: both forms require low temperature and high salinity for survival. L. saccharina has a wide range of tolerance to temperature and salinity; surf appears to be the controlling agent.