We found larval clownfish have the highest oxygen uptake rates of any fish to date. Larval reef fish returning home from the open ocean must prepare for such conditions. Why hypoxia? At night, when it’s no longer possible to use sunshine and carbon dioxide to make energy by photosynthesis, corals and plants breathe in oxygen to make energy. These traits included swimming speed, oxygen uptake rates, gene expression patterns, and tolerance to low oxygen (hypoxia). My colleagues and I measured physiological traits required to be an athletic swimmer across the entire larval phase of a clownfish. Joe Belanger, Shutterstock Measuring the traits of an athlete Now we know.Ĭlownfish eggs begin as tiny orange spots, but they soon start to lengthen and acquire visible eyes. When paired with well-developed sensory systems such as vision and the sense of smell, such impressive athletic performance enables these babies to “just keep swimming” with or against ocean currents until they find an optimal reef on which to settle.īut 30 years after the discovery, we were still wondering how they manage it.

For comparison, Olympic multi-gold medallist Michael Phelps races at just under two body lengths per second. Some of these tiny athletes are capable of swimming 10-50 body lengths per second as a larva. Previous research has provided overwhelming evidence coral reef fishes are capable of amazing swimming performance as babies. It turns out reef fish are not passive particles after all. However, landmark studies from the early 1990s documented the impressive swimming capabilities of baby reef fish. These species “go with the flow”, passively riding ocean currents until they become large and developed enough to actively swim on their own, against the currents. Until the 1990s, scientists believed the development of larval reef fish was like that of other fish such as herring, cod and flatfish. Depending on the species, they cover distances as far as 64 kilometres. It’s a long, arduous journey that can last weeks to months. Within a few weeks the tiny fish larvae must return to the reef. Their eggs are carried off by wave action into the open ocean, where they hatch and develop.

Plus, their vibrant colours attract millions of tourists annually.Īdult reef fish keep to a small patch. They play important roles in the food web, help keep the reef clean and recycle nutrients. Reef fish are vital to coral reef ecosystems. Mini athletes swimming 10-50 body lengths per second Dazzling or deceptive? The markings of coral reef fish

Just enough research 2nd edition