LARVAL REEF FISH RESPOND TO DIMETHYL SULFIDE AND HOME TO ITS SOURCE
Transport of coral reef fish larvae is driven by advection in ocean currents and larval swimming. For swimming to be advantageous, larvae must use external stimuli as guides. A potential stimulus is “odor” emanating from coral reefs, which signals the upstream location of desirable habitat. However, specific chemicals and mechanisms for plume tracking have not yet been identified. Dimethyl sulfide (DMS) is produced in large quantities at coral reefs and may be an important cue. In this study, a choice-chamber (shuttle box) was used to assess preference of reef fish larvae for water with DMS and potential changes in swimming behavior. Video tracking of larval movement was used to compare swimming patterns in control and DMS seawater. We found a common response to the presence of DMS across taxa – a preference for water with DMS and a significant increase in turning frequency - reflecting a switch to “search behavior”. Detailed patterns of movement when encountering a dyed DMS plume were monitored in a large flume tank to assess whether and how larvae were able to locate the source of DMS. Larvae quickly located the source of odorous plume injections in the flume but did not respond to plumes of non-odorous dye in seawater. Affinity for and swimming response to relevant concentrations of DMS allows a fish larva to locate its source and would enhance its ability to find settlement sites. Moreover, it may help them locate high concentrations of prey accumulating in fronts, eddies, and thin layers, where DMS is also produced.
Foretich, M. A., Rosenstiel School of Marine and Atmospheric Science, USA, email@example.com
Chaput, R., Rosenstiel School of Marine and Atmospheric Science, USA, firstname.lastname@example.org
Paris, C. B., Rosenstiel School of Marine and Atmospheric Science, USA, email@example.com
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