The Associates of Four Species of Marine Sponges of Oregon and Washington

Abstract

Four species of sponge from the coasts of Oregon and Washington were studied and dissected for inhabitants and associates. The four species differed in texture, composition, and habitat, and likewise, the populations of associates of each differed, even when samples of two of these species were found adjacent to one another. Generally, the relationships of the associates to the host sponges were of four sorts: (1) inquilinism or lodging, either accidental or intentional; (2) predation or grazing; (3) competition for space resulting in "co-habitation" of an area (i.e., a plant or animal growing up through a sponge); and (4) mutualism. Fish eggs in the hollow chambers of Homaxinella sp. represented fish-in-sponge inquilinism, which is the first such instance reported in the Pacific Ocean and in this sponge. The sponge Halichondria panicea, with an intracellular algal symbiont, was found to emit an attractant into the water, which Archidoris montereyensis followed, in behavior experiments, in preference to other sponges simultaneously offered. A total of 6,098 organisms, representing 68 species, were found associated with the samples of Halichondria panicea with densities of up to 19 organisms per cm3 of sponge tissue. There were 9,581 plants and animals found with Microciona prolifera, and 150 with Suberites lata.