MIAMI The behavior of marine larvae is central to fully understanding and modeling the pelagic (open ocean) stage for many coastal organisms. For the first time, a numerical study conducted by the University of Miami (UM) incorporates horizontal larval fish navigation skills into realistic 3D flow fields, creating a powerful tool that spells out how larvae use environmental cues to find their way back to the reef after being out on the open ocean. The new model uses reliable larval swimming speeds and vertical migration, known life history traits and spawning time to create realistic scenarios that can be studied in detail.
In an article entitled: "Orientation behavior in fish larvae: A missing piece to Hjort's critical period hypothesis" that appears in the latest edition of the Journal of Theoretical Biology, scientists Erica Staaterman, Claire Paris* and Judith Helgers demonstrate that despite very low swimming speeds -- approximately a few centimeters per second -- orientation behavior during early stages is critical to bringing larvae back to the juvenile habitat. The research team shows that baby reef-fish must possess, as early as possible, the ability to sense cues radiating from the habitat that help them to navigate and survive the pelagic phase.
The team used Hjort's "critical period" hypothesis, which says that fish recruitment variability is driven by the fate of the earliest larval stages, and that food and "aberrant drift" are the main factors contributing to the survivorship during this early phase. According to this hypothesis, the proportion of survivors during this "critical" larval phase is carried over throughout the entire life history of the fish's population.
"Orientation during the "critical period" appears to have remarkable demographic consequences," said UM Applied Marine Physics Professor Paris. "Larvae need to orient themselves soon after hatching to increase their chance to find any reef
|Contact: Barbra Gonzalez, UM Rosenstiel School|
University of Miami Rosenstiel School of Marine & Atmospheric Science