February 5, 2021 — The following was released by NOAA Fisheries:
To survive the open ocean, freshly hatched tiny fish larvae must find food, avoid predators, and navigate ocean currents. Their experiences during these great ocean odysseys have long been a mystery, until now. We have discovered that a surprisingly dense and diverse array of marine animals find refuge in so-called “surface slicks” during early life. To view an immersive, interactive version of this story, check out our story map: Hidden World Just Below the Surface.
Surface slicks are home to the larvae of at least 112 marine fish species, including commercially and ecologically important fish such as mahi-mahi, jacks, and billfish. Serving as makeshift nursery habitats, surface slicks are meandering lines of smooth surface water that collect plankton and shelter-providing debris. They are formed from the convergence of ocean currents, tides, and variations in the seafloor.
“These ‘bioslicks’ form an interconnected superhighway of rich nursery habitat that accumulate and attract thousands of young fish, along with dense concentrations of food and shelter,” says Dr. Jonathan Whitney, a research marine ecologist for NOAA and lead author of the study, published today in Scientific Reports. “The fact that surface slicks host such a large proportion of larvae, along with the resources they need to survive, tells us they are critical for the replenishment of adult fish populations.”
That larvae hosted in slick nurseries grow up and radiate out into neighboring ecosystems. There, they join adult fish populations from shallow coral reefs to the open ocean to the bottom of the deep sea.
What’s more, many forage (prey) fish, like flying fish, spend their larval and juvenile life stages in surface slicks. “These biological hotspots provide more food at the base of the food chain that amplifies energy up to top predators,” says study co-author Dr. Jamison Gove, a research oceanographer for NOAA. “This ultimately enhances fisheries and ecosystem productivity.”