According to a study, over 500 commonly occurring fish, seaweed, coral, and invertebrate species that inhabit Australian reefs have decreased over the past ten years. Experts have warned that “not everything is well in the ocean.”
With marine heatwaves and an increase in ocean temperatures affecting species that reside on stony and coral reefs, global warming was likely the primary cause of the decline.
In study, which was published in journal Nature, 1,057 species were monitored. It was discovered that 57% of them had declined, and nearly 300 of them were declining at a rate that might make them threatened species.
The species that reside in calmer waters were particularly heavily hit, with over 28% of the species examined experiencing 30% or more declines in just a decade.
The decreases were most pronounced in the Great Southern Reef, a group of rocky kelp-dominated reefs in Australia’s calmer southern waters, according to Prof. Graham Edgar, a marine ecologist at University of Tasmania and study’s principal author.
He said, “These declines are taking place out of the public eye and with very little public notice.”
According to Edgar, many additional sea species need to be observed and are almost certainly in decline.
“In reality, what we see here is only the tip of the iceberg. Species could be disappearing right now, he warned.
“I find this to be very worrying. For more than 30 years, I’ve been swimming up and down, counting fish and seaweed, and I’ve witnessed climate change’s effects on the system. It’s concerning the way things are going.
According to Edgar, the loss of kelp was particularly significant because it served as the foundation for numerous habitats in the continent’s calmer waters.
The study discovered larger fish fell faster than smaller ones, perhaps due to fishing pressure amplified by warming temperatures.
The study, which drew on historical data from the Australian Institute of Marine Science and observation from a large group of volunteer divers, involved 35 researchers from several universities.
We only considered species that had been sighted frequently enough to warrant investigation.
According to Edgar, we completed this task with the volunteer contributions of Reef Live Survey divers.
According to scientists, rising ocean temperatures pose an “existential threat” to many reef species, with repercussions for ecosystems and commercial fisheries.
Not only were the oceans rising, but pollution, coastal development, fishing, aquaculture, and land runoff were impacting the species in the southern waterways of Australia, which were nearer to major cities like Melbourne, Adelaide, and Sydney.
Despite the study’s primary focus on species found on reefs, the scientists concluded that marine wildlife in another fast warming, calm temperate waters were likely also in decline.
Dr John Turnbull, a marine ecologist and co-author of the paper, has seen decreases as a volunteer diver.
He noticed a clear drop in the weedy sea dragons and urchins population and the first bleaching of cold water corals near Sydney.
“We have firsthand knowledge of these declines. According to him, the losses in southern Australia have not been well known.
He said that the disappearance of urchins had a ripple effect since they provided food for larger fish, such as blue gropers, which can reach a length of a meter.
Turnbull noted that there was evidence that certain species were relocating to the more excellent portions of their ranges, which was problematic in southern waters since animals “run out of runway” without sufficient habitat further south.
Associate The study, according to Prof. Zoe Richards of Curtin University and the Western Australian Museum, “sends a strong message that not all is well in the water.”
Richards, who was not involved in study, stated that it “provides much-needed empirical proof that population losses are occurring even among the most common marine taxa.”
These species are widespread, making them significant contributors to the health of various ecosystems. If they are slipping, it is pretty concerning.