New study of endangered whale shark youth shows vital habitat similarities

Sunday, June 10, 2018

In findings published on Friday in PeerJ, an open-access peer-reviewed scientific journal, researchers from the University of York and Maldives Whale Shark Research Programme have mapped key habitats of the world's largest fish, the whale shark, shedding light on congregation sites that have perplexed marine biologists.

According to the researchers, Whale sharks, Rhincodon typus, listed as endangered under the IUCN Red List, do feed in the open ocean, but juveniles tend to form large groups in only about 20 to 25 specific places around the coasts of Mexico, Belize, the Maldives, and Australia, which previous research has not explained. The research team reviewed dozens of previous papers, compiled their findings into a database, and performed spatial analysis with the aggregate shark-related event data. Results showed the sharks' frequented sites had areas of very shallow water near a steep drop-off into the depths, such as a shelf break or reef slope.

The whale shark can grow to eighteen metres (60 ft) in length. Unlike its better-known relatives, the Great white shark and other predatory sharks, the whale shark is a filter feeder, meaning that it draws water into its mouth and extracts small organisms from the liquid. They can search for food at the surface of the ocean but are also known to dive deep. According to supervising author Dr Bryce Stewart, PhD, "Sharks are ectotherms, which means they depend on external sources of body heat. Because they may dive down to feed at depths of more than 1900 metres, where the water temperature can be as cold as four degrees, they need somewhere close by to rest and get their body temperature back up. Steep slopes in the seabed also cause an upwelling of sea currents that stimulate plankton and small crustaceans such as krill that the whale sharks feed on."

Such sites are also attractive to fishing and recreational boating, and collisions can injure sharks. Stewart emphasized the importance of using research to help preserve and protect the sharks, calling them, "extremely valuable to local people on the coastlines where they gather, which are often in developing countries. While a whale shark can be worth as much as $250,000 USD dead, alive it can provide more than $2 Million USD over the course of its life span." The latter figure specifically estimates only ecotourism.

Have an opinion on this story? Share it!

Sources

Joshua P. Copping, Bryce D. Stewart, Colin J. McClean, James Hancock, Richard Rees. "Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations?" — PeerJ, June 8, 2018

University of York. "Research reveals secret to whale shark hotspots" — Eurekalert, June 8, 2018
Elena Montivans. "Whale sharks are very picky about where they live, which could be bad for their survival" — ZME Science, June 8, 2018

Share this:

This page is archived, and is no longer publicly editable.

Articles presented on Wikinews reflect the specific time at which they were written and published, and do not attempt to encompass events or knowledge which occur or become known after their publication.

Got a correction? Add the template {{editprotected}} to the talk page along with your corrections, and it will be brought to the attention of the administrators.

Please note that due to our archival policy, we will not alter or update the content of articles that are archived, but will only accept requests to make grammatical and formatting corrections.

Note that some listed sources or external links may no longer be available online due to age.

The text of this article is licensed under the terms of the Creative Commons Attribution 2.5 License