This article was originally hakai magazine, Online publication on science and society in coastal ecosystems.Read more articles like this hakaimagazine.com.
A black rope scraped the whale’s raw meat white, making it easier for marine mammal rescuers to see a months-old humpback whale entangled in fishing gear off Cape Cod, Massachusetts. Rescue workers at the Center for Coastal Studies (CCS) used her 9-meter pole with a sharp hook at the tip to detach the tangled gear. This is he one of similar rescue efforts the team does every year.
The majority of the team’s rescue attempts are successful. But for CCS Rescue His Operations his manager Bob Lynch, their efforts are little more than a first aid measure. There are many whales they cannot reach, he says. Beyond that, detangling can save whales, but it can’t save the species, says Lynch. “What we’re doing is not the solution to the problem.” Preventing whales from becoming entangled in the first place has a significant impact on their conservation.
Vessel collisions and entanglement in fishing gear are the main causes of human mortality for humpback and other baleen whales. Over the past few years, scientists and conservationists around the world have tried all kinds of things, including testing, to prevent entanglement. ropeless gear,gain Marine litter cleaning activity, the implementation of seasonal closures in areas frequented by whales. But off the Massachusetts coast, research led by Tammy Silva, a marine ecologist at the Stellwagen Bank National Marine Sanctuary (SBNMS), suggests another way to spot and hopefully prevent whale entanglement. increase. Key to this approach is the overlapping habitat use between the humpback whale and her one species of seabird, the streaked shearwater.
Streaked shearwaters often congregate in the hundreds in the choppy waters off SBNMS north of Cape Cod Bay. Through tracking, Silva and her colleagues have shown that gatherings of streaked shearwaters can signal that a pod of humpback whales is swimming below. Both species are preparing for offshore feasts. A whale rises from the deep waters and captures a silver lance, an eel-like fish. Petrels are waiting for whales to pick from what they have missed.
While it is possible to track whales directly using satellite tags, this approach can be expensive and the tags have a short lifespan. Capturing and tagging seabirds is much easier than tagging humpback whales, according to SBNMS research coordinator Dave Wiley.
Tracking a petrel starts with getting the bird, Silva explains. Streaked shearwaters spend most of their lives in the open ocean and migrate to land only to breed, so researchers have to catch them at sea. So the team has choreographed what Silva describes as an alien abduction every year since his 2012.
Three or four team members launched in small inflatable boats from the mothership, a 15-meter vessel in the Gulf of Maine, and set off to follow the petrel rafts. One team member throws fillets of mackerel and squid to lure the birds, while others use long hand-held nets to scoop the birds into the boat. Work quickly to minimize stress on the animal and place each bird in the cat carrier to relax.
After catching a few birds, return to the mothership. So scientists collect samples to gauge each bird’s health and diet, then sew tiny solar-powered satellite tags into the skin between their wings.
58 birds tagged and tracked in 5 years clarified Significant overlap in where and when streaked shearwaters and humpback whales meet en masse. Silva and her colleagues now hope to use this data to save humpback whales from life-threatening entanglements.
Identifying known persistent hotspot overlaps like SBNMS means we can now look further ashore. “Take George’s Bank for example, nobody goes to George’s Bank looking for humpback whales,” Wiley says. However, if sufficient numbers of petrels appear in the area between Cape Cod and Nova Scotia at a particular time of day, it’s likely that humpback whales are also in the area.
Much work remains to develop a real-time, bird-based system that predicts the presence of humpback whales. But the team hopes that detecting flocks of tagged birds in the future will inspire ocean management teams to take action. Fishermen will need to move their gear and boaters may be asked to avoid the area.
This is much like how mobile phones and smartwatches track their owner’s location through continuous updates of information. Silva says:
Maintaining long-term data collection from petrels is central to both Wiley and Silva’s hopes for the future of the project. As a highly migratory species, seabirds are the best indicators of ocean patterns and help answer important questions about the health of marine life. Including whales. Conserving humpback whales requires a different approach, says Silva. “Ultimately, coexistence is what we are looking for.”
This article first appeared on hakai magazine, Republished here with permission.
