The nurse shark (Ginglymostoma cirratum) is a little-studied species commonly found in tropical and subtropical waters across the world. Now researchers have used underwater cameras to advance their understanding of nurse shark feeding behaviors, discovering that these elasmobranchs are basically underwater acrobats in the process.
“Despite their widespread nature, we know comparatively little about nurse shark behaviour relative to other coastal species, so this study provides an important step to further understanding their ecological role,” said Dr Oliver Shipley, Senior Research Scientist at Beneath The Waves, in a statement seen by IFLScience.
By using baited underwater video cameras positioned in the waters off Turks and Caicos from September 2020 to April 2021, the team identified a host of new foraging behaviors. A total of 233 observations from 71 cameras revealed that stationary feeding behavior was the most frequently observed, occurring on sandbanks much more often than reef habitat.
The cameras also revealed a snazzy new behavior captured on video for the first time. Nurse sharks are related to epaulette sharks that can famously “walk” on land. The cameras revealed that nurse sharks use a method called pectoral positioning to move closer to a food source through manipulation of their pectoral fins. This is thought to be the first empirical evidence of pectoral positioning in wild nurse sharks.
Video credit: Parton, K.J. et al (2022) Environmental Biology of Fishes
The researchers recognize the limitations of the study, being that by using baited canisters they may not be accurately recording true wild behaviors. However they conclude with the idea that this research has helped expand the knowledge surrounding nurse shark feeding ecology.
“These feeding behaviours show that nurse sharks are adapted to feed on different prey across a variety of habitats,” said lead author Kristian Parton, of the Centre for Ecology and Conservation at the University of Exeter’s Penryn Campus in Cornwall.
The study is published in Environmental Biology of Fishes.