The Associates of Four Species of Marine Sponges 
of Oregon and Washington 
Edward R. Long 1 * 
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) preda- 
tion 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 cm 3 of 
sponge tissue. There were 9,581 plants and animals found with Microciona prolifer a, 
and 150 with Suherites lata. 
Sponges frequently serve as hosts for many 
plant and animal associates. The relationships 
of such organisms vary from loose lodging or 
inquilinism to mutualism, a close type of sym- 
biosis. The first account of sponge symbiosis 
was that of Radcliffe (1917) in which he re- 
ported the goby Garmannia spongicola living 
within unidentified sponges off North Carolina. 
Other early reports include those of Vosmaer 
(1911) who found invertebrates in the canals 
of tropical sponges, and Ridley and Dendy 
(1887) who found a very abundant oscillator- 
ian alga in Halichondria panicea. 
Perhaps the most significant reports concern- 
ing sponge symbioses were those of Pearse 
(1935, 1949) who described the inhabitants 
of various Caribbean sponges, Gudger (1935) 
who found many fish living in Atlantic sponges, 
and Forbes (1964, 1966) who described the 
mutualistic relationship between the sponge 
Stellata gruhii and the oyster Ostrea permollis 
1 Department of Zoology, Oregon State University. 
Present address: U.S. Naval Oceanographic Office, 
Washington, D.C. 20390. Manuscript received July 
18, 1967. 
from the Gulf of Mexico. Caullery (1952), 
Dales (1957), Nicol (1964), and Henry 
(1966) have summarized the symbiotic relation- 
ships of marine animals and included in their 
descriptions many previous reports of sponge 
symbioses. The following is a description of the 
associates of four species of sponge, three 
subtidal and one intertidal in Pacific Northwest 
marine waters. 
METHODS AND MATERIALS 
Because the sponges studied occupied varied 
habitats, the methods of collection differed. 
Microciona prolifera and Suherites lata, which 
were subtidal, were obtained with scuba. They 
were pulled or scraped off their substrate and 
immediately placed into zippered plastic bags 
which were sealed underwater. Halichondria 
panicea, which occurred intertidally upon un- 
protected rocks, was scraped off the rocks by use 
of the fingernails and placed into plastic bags. 
Homaxinella sp. was collected from 10 to 15 
fathoms with an otter trawl. The collected speci- 
mens were subsequently taken to the laboratory 
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