Southeastern a climate change hot spot, with shifting currents and significant increases in water temps
By Summit Voice
SUMMIT COUNTY — Warm-water fish around Australia are moving southward to colonize the cool, temperate waters of the Tasman Sea, according to Australian researchers who recently concluded that as many as 43 species are showing shifts thought to be related to global warming. The changes are affecting about 30 percent of the inshore fish families in the region.
The scientists with the Commonwealth Scientific and Industrial Research Organization (CSIRO) scoured published accounts, scientific surveys, records from spearfishing and angling competitions, as well as tallies of commercial catches and underwater photographic records from the late 1800s to the present.
“Increased water temperatures in the Tasman Sea are likely to have a cascading effect through local marine ecosystems.” said Dr. Peter Last, curator of the Australian National Fish Collection. “Furthermore, up to 19 species, or 5 per cent, of Tasmanian coastal fish fauna have undergone serious declines or are possibly extinct locally,” Last said.
Affected fish include warm temperate surf-zone species such as Silver Drummer and Rock Blackfish that are breeding and have become more abundant, and range increases in Snapper and Rock Flathead. There is also a greater abundance of warm water tunas and billfishes and occasional visits from Queensland grouper and tiger sharks.
“Shifts in the distribution of marine animals in response to climate change can be detrimental to some species. The problem is that in southern Tasmania, shallow cold water species have nowhere to escape warmer conditions in the sea,” Dr Last says.
Last said south-eastern Australia is a climate change hotspot with well-documented changes already occurring over the past 70 years, including southward penetration of the East Australian Current by about 350 kilometers and a temperature rise of almost 2 degrees Celsius.
“Increased water temperatures in the Tasman Sea are likely to have a cascading effect through local marine ecosystems and, for example, the Bass Strait islands act as stepping stones or distributional pathways south. Already we are seeing biological responses to these changes in the increased presence of sea urchins and fishes from further north,” he concluded.
Filed under: Environment, global warming, Summit County Colorado Tagged: | Australia, Bass Strait, climate change, Commonwealth Scientific and Industrial Research Organisation, conservation, Summit County Colorado, Summit County News, Tasmania, wildlife