Great Ocean Migrations

Satellite telemetry is a widely used tool to track the migration routes of numerous animals. Previously, sea turtles have been mainly studied while nesting on beaches, but these observations do little to inform scientists of what these animals are doing the majority of their time, which is spent away from their nests. Satellite imagery has allowed researchers to monitor the activity of these animals in the open ocean (image below from the Sea Turtle Conservancy). Data collected using this technique have shown that sea turtles will travel hundreds to thousands of miles between nesting beaches and feeding areas out in the ocean.

Scientists from the University of Miami (UM) Rosenstiel School of Marine & Atmospheric Science, recently published preliminary findings on the migration of hammerhead sharks (shown in the image below taken by Neil Hammerschlag, lead investigator). They found that these endangered sharks migrate into international waters where they may be at risk of illegal fishing. You can read the abstract from the article here. Dr. Hammerschlag's team is working hard to map the feeding, mating and pupping areas of these sharks to help in their conservation.

Perhaps one of the most beautiful migrations to see are those of stingrays (shown in image below from the Daily Mail.com). You can watch a short clip of these animals here.

The migration of humpback whales has also been studied using satellite imagery. An article published in Biology Letters describes the longest documented mammalian migration involving humpback whales traveling from their wintering grounds in coastal Central America to their feeding grounds off of the Antarctic Peninsula. The researchers tracked animal migration and water temperatures in this study to discover that warm waters were the driving force for their long migrations. So how might climate change affect the migratory behavior of these animals?

Several species of fish also migrate. In this article published in Fish and Fisheries, the effects of climate change on fish migratory routes was explored. Researchers Cheung et al., developed climate change models and predicted that by 2050, large numbers of fish will invade the Arctic and Southern Oceans resulting in local extinctions.

These studies show the importance of considering environmental influences on the migratory behaviors of animals.

Stay tuned for great air and land migrations next week!