Why are fish in Australia migrating south?
Researchers from the University of Tasmania have found that at least 35 species of fish have changed their migration and egg-laying patterns as a result of temperature changes in the ocean, and other significant factors.
The 35 species of fish were chosen for the study based on their significance to the commercial fishing industry, and their ecological importance.
Scientists assessed how the fish species were distributed, the number of eggs they laid and their ability to migrate. They found that most fish species were moving to cooler waters in order to survive.
- Different species of fish had different responses to increased water temperature and changes in nutrient and plankton levels in the water.
- Species like abalone, southern calamari, western king prawn, southern rock lobster and blue swimmer crab were more impacted by changes in water temperature.
- Australian salmon were also likely to experience a large change in migration patterns due to changed currents and wind conditions.
- Most of the species studied would need to change their habits, at least in some small way.
- Not every species would be disastrously impacted, with many capable of shifting towards warmer waters.
- Species unable to migrate may shrink in size, as those who cannot tolerate cooler waters are likely to die out.
- Some species were more likely to be seen outside their usual migration zones, including coral trout, which has been sited as far as NSW, and Whale Sharks, which have been seen as South as Perth, WA.
- International data from 2013 said fish were moving towards the poles at a rate of around 7km every year. Scientists found fish species were seeking climates they could better survive in.
- For the full source article head to theguardian.com.
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