What benifits and disadvantages can epibionts and basibionts have from epibiosis?

Benifits for epibiont: - better irradiance for algee epibionts - more water velocity for filter feeders like barncles Disadvantage for epibiont: - trophic competition with basibiont - environmental changes if host migrates Disadvantages for basibiont and also both in manyy cases: - if booth are food for same predator (shared doom) - also musle covered by barnecles are easier to crush for crabs - competition with epibiont (exploitation) - competition for nutrients (algee) - reduced reproductive output benifits for basibiont: - Associational defence (protection gained from living in close relation to different organism)