Featured Image Credit: Alex Mustard/NaturePL.com
By Eva Gruber
Marine ecologists are concerned with the decline of one of the oceans most iconic species – the dream-like weedy sea dragon, native to eastern Australian waters, has experienced a noticeable drop in numbers. Scuba divers who once enjoyed seeing these gentle fish regularly are no longer reporting them on dives.
Seeing one is now a lucky occurrence, and seeing none is becoming the new normal.
Many dive sites that hold names such as “Dragon Alley”, named after the abundance of sea dragons, are no longer home to the species. Many other sites have been devastated as well, such as Botany Bay, where Captain James Cook first landed on the continent 250 years ago.
This presents a major challenge to the University of Technology Sydney’s recent “facial recognition” study, funded by SeaWorld on the Gold Coast, which needs to find weedy sea dragons for their information.
Going from site to site, once popular for sea dragons, the divers had a hard time to find individuals. At one pier near Sydney, which previously had around 60 sea dragons along its length, the divers could find only eight.
Climate change is the likely major culprit here – as it is with so many marine conservation issues. With warming waters, the sensitive habitat the weedy sea dragon calls home is becoming degraded. Algae and corals that the sea dragons depend on are dying, unable to cope with the rise in temperature and changes in water chemistry.
The dangers to a species compound as their population becomes endangered. With fewer individuals, the gene pool becomes severely limited and genetic diversity drops. This is often the final straw for many endangered species. With lower genetic diversity, the population is more susceptible to diseases and environmental changes. Time will tell whether the weedy sea dragon can cope with all this.