How do larvae choose a place to settle?

They use global cues, regional cues and site specific cues Global cues: are used to find a good site. They could use cues from light (to get to current to get transported to suitable area), pressure and so on Regional cues: when they find a suitable area they use regional cues to find the right spot. could be chemical cues. for instance barnecles like spots where barnecles are already present - areas where they are already is better for survival. I would argue that sexual reproduction also. Site specific cues: Very local cues such as texture of substrate (for instance barnicles don't like too smooth surfaces), light, contact chemicals. larvae have a certain time where they can settle if they run out of time they will settle even if conditions are not great