UBC researchers expect large-scale shift of marine fish and invertebrates

The undersea realm is going through major changes, and the driving force seems to be climate change, according to aquatic ecologists from the University of British Columbia. A fall 2014 report by the UBC revealed some disturbing information about marine fish and invertebrates: Warming of the oceans is pushing these species into the cooler Arctic and Antarctic waters, and large amounts will disappear from the tropics by the year 2050.

This revelation came about thanks to a study published in ICES Journal of Marine Science and led by Dr. William Cheung, associate professor at the UBC Fisheries Centre, and colleagues. For the project, they used modeling to determine the best- and worst-case scenarios:

  • Best case: The Earth's ocean warms by about 1.8 degrees Fahrenheit by 2100, in which case fish would travel away at around 10 miles every decade.
  • Worst case: The Earth's ocean warmed by 5.4 degrees Fahrenheit by 2100. In this situation, fish may leave their habitats in the tropics by a rate of up to 16 miles per decade.

By applying the same climate change scenarios used by the Intergovernmental Panel on Climate Change, Cheung and his colleagues predicted that more than 800 commercially significant fish and invertebrate species will react to these warming temperatures and move toward the pole.

"The tropics will be the overall losers," Cheung said. "This area has a high dependence on fish for food, diet and nutrition. We'll see a loss of fish populations that are important to the fisheries and communities in these regions."

As the tropics see a decline in fish stock, the Arctic will see a surge. This may provide new opportunities for fisheries in the region; however, it could potentially mean increased competition for resources and disruptions to the fish and invertebrates that live in those waters now. Further research into the aquatic ecology of the Arctic will be needed for more accurate predictions about the future of these habitats.

The ongoing issue of ocean warming
Climate change has been a major issue in the aquatic ecology realm for nearly half a century, as experts have found increasing rates of species relocating to deeper and cooler waters. In fact, Cheung and his cast of researchers delved into the subject in 2013, when they published a study that assessed the way climate change affected the oceans from 1970 and 2006. The results showed that fisheries were relying more heavily on warm-water fish for their catches, the result of species in leaving their ecosystems to find relief from the increasing temperatures of the ocean waters. As Daniel Pauly, the study's co-author and principal investigator of the UBC Sea Around Us Project, stated in a UBC news release, it brought light to the urgency of climate change.

"We've been talking about climate change as if it's something that's going to happen in the distant future – our study shows that it has been affecting our fisheries and oceans for decades," Pauly said. "These global changes have implications for everyone in every part of the planet."

This past study accurately foretold the devastating effects that climate change proved to have. In the waters of Australia, Japan and the eastern Mediterranean, tropical fish are invading as they escape from warming waters and quickly eating away at kelp forests, thereby uprooting the communities of species that live there. For instance, the influx of parrot fish and rabbitfish in Japan's waters has diminished 40 percent of the kelp forests, devastating the abalone and spiny lobster that lived off those seaweeds as well as the fisheries that relied on these native creatures.