Abstract: Seaweeds have various ecological functions in marine ecosystems. As for their conservation function, most studies have focused on their conservation effect on high trophic level, such as fish, gastropod, and mussel. However, little is known about the conservation effect of seaweeds on bait organisms. Here, we reported the conservation function of epiphytic seaweeds on seaweed-associated bait organisms such as amphipods in a raft musselculture area. Sampling was carried out in the raftmusselculture area of northwestern Gouqi Island in May 2017. A total of 32 species of epiphytic seaweeds were collected, belonging to three phyla:Rhodophyta,Phaeophyta, and Chlorophyta. Plenty of amphipods (mainly Gammaridea and Caprellidae) were observed attaching on the surface of the epiphytic seaweeds. The mean biomass of the amphipods attached on per gram of epiphytic seaweeds was 0.073±0.034 g (df=29,a=0.05), while their abundance reached as high as 7.63±4.07 ind·g^-1 (df=29, a=0.05). There were positive correlations between amphipod biomass and seaweed biomass (r=0.43,n=28,P<0.05) and between Gammarida abundance and seaweed biomass (r=0.50,n=28,P<0.01). Caprellidae abundance did not change with increasing seaweed biomass (r=0.26, n=28, P>0.1). The average individual size of Gammaridea significantly increased with seaweed richness (r=0.71, n=30, P<0.001), whereas there was no significant correlation between individual size of Caprellidaeand seaweed richness (r=-0.13, n=30, P>0.1). In conclusion, our results indicated that seaweeds are beneficial for the growth of seaweed associated Gammaridea and Caprellidae. The mechanisms of seaweed conservation effects on them are different, which may be related to the species specific functions of seaweeds and ecological habits of amphipods.

Key words: house price, house age, hypothesis of luxury effect, greenspace coverage, population density, hypothesis of legacy effect