A new study, published in the journal Proceedings of the Royal Society B, shows that tropical fish, like unicornfish, parrotfish and rabbitfish, migrating due to ocean warming pose a threat to the kelp forest and seagrass meadows. They were found to be overgrazing the kelp forests.
The declines in kelps in Southern Japanese waters and Eastern Mediterranean reflect the dangerous effect of the tropical fish. Evidence also points that the massive spread of these tropical fish towards the poles in Australia and the United States is causing damage to that particular area.
Dr. Adriana Verges, lead author of the study from University of New South Wales said, "The tropicalisation of temperate marine areas is a new phenomenon of global significance that has arisen because of climate change. Increases in the number of plant-eating tropical fish can profoundly alter ecosystems and lead to barren reefs, affecting the biodiversity of these regions, with significant economic and management impacts."
Due to climate change, the oceans have become warm and currents in the warm tropical waters are strengthening. In Japan, U.S., Brazil and Africa, the waters are influenced by the warm currents.
Dr. Verges explained that in tropical regions, a wide diversity of plant-eating fish perform the vital role of keeping reefs free of large seaweeds, allowing corals to flourish. But when they intrude into temperate waters they pose a significant threat to these habitats. They can directly overgraze algal forests as well as prevent the recovery of algae that have been damaged for other reasons.
The researchers suggest that this migration could threaten the lobster industry in Australia. Adriana Verges noted that abalone are associated with kelp and they're only found where there's kelp or other kind of big seaweeds. She continued that this has economic implications and that other species that depend on kelp like lobster and a whole other host of fish.
To prevent the tropical fish from overgrazing the kelps, Verges suggests that we should definitely try and stop CO2 emissions and that any efforts to stop climate change are going to be key in at least slowing down this process.