New research describing the location of biological hotspots off B.C.’s Central Coast will support efforts to protect the vulnerable and ecologically significant species they contain.
Published in the journal Scientific Reports, the study entitled “Hotspots for rockfishes, structural corals, and large‐bodied sponges along the central coast of Pacific Canada,” is the result of collaboration between scientists from Fisheries and Oceans Canada and Central Coast Indigenous Resource Alliance. Analyzing data collected over 11 years using a variety of sampling techniques, including scuba diving and remote cameras, these researchers described the location and depth of three species groups: rockfish, sponges, and corals.
They identified “biological hotspots” in the region where members of these groups are abundant and diverse. Not only were these hotspots found in the deeper ocean, but also into the Central Coast’s fjords and inland channels, said Alejandro Frid, one of the study’s lead authors.
“Even up in the fjords, there are some very substantial coral aggregations, what we call ‘sponge gardens,’ and also some of the deepwater rockfishes normally associated with more oceanic waters,” said Frid.
Members of these three study groups are important to marine ecosystems in the area.
As top predators, rockfish shape marine food webs, increasing diversity. Sponges filter bacteria, viruses and toxins, cycle carbon, and provide food and shelter for other species. Corals provide habitat for other species, including rockfish, and also store carbon, Frid said.
But these groups are also vulnerable to human impacts, including direct and indirect effects of commercial fishing.
Rockfish have declined from overharvesting, as they are slow to mature and reproduce, while sponges and corals are often physically damaged by fishing gear such as long lines and traps.
The researchers combined the hotspot maps for each group to create “a very sophisticated and rigorous description of where the overall most important areas are,” he said.
This map will complement local and traditional knowledge to inform a federal technical group working to determine where new marine protected areas should be sited in the region. But given the vulnerability of the focal species and the time it takes to design and implement such protected areas, Frid said hotspots should be considered for interim protection now.
Reducing fishing pressure by protecting these hotspot locations could help these marine species overcome impacts of climate change, including warming, acidification, and decreasing oxygen, he said.
“Of the two major stressors, climate change and fisheries, it’s fisheries we can manage better and much more immediately,” he said. “So by setting aside these protected areas, the species groups are going to be able to absorb climate shocks better, by reducing that other major stressors.”