PETERSBURG – Earlier this month a team of Oregon State University researchers visited Southeast to tag humpback whales and track their winter migration. The four person team is part of a Marine Mammal Institute (MMI) study that began tagging the endangered species last November.
The goal of the two year study is to answer questions like how wide their travel range really is, where they congregate, how long they stay in specific places, and when they depart after staying in a specific place or area.
These may seem like basic questions, but a lot of the time, researchers have no answers to them, says Ladd Irvine, MMI senior faculty research assistant. This type of research was pioneered by MMI director Bruce Mate in the 70s. The majority of research on whales is not detailed, and researchers know a lot of areas in Southeast have whales, but not much is known about the timing of their coming and going. These are important questions to understand the best ways to manage the species, he says.
“We’re trying to get a detailed representation of the entire migratory cycle of the humpback there in Southeast,” Irvine says. “We can hopefully conserve them and help their populations recover from whaling.”
In the early-1960s, the global population was reduced to around 5,000 due to whaling, which eventually led to the practice being banned and the species being listed as endangered. Removing the threat of whaling and the establishing of a support system of people who genuinely care about the species was the turning point. Currently, the worldwide population is sitting at about 80,000, with around 18,000 to 20,000 in north Pacific waters. The majority of whales from Southeast travel to Hawaii, and about 15 percent go toward Mexico, according to Irvine.
The MMI conducts up to four field projects a year for usually three to four weeks. However, the four person team only spends 10 days tagging whales, and the rest of time is spent in the office crunching numbers, completing reports and writing papers.
Irvine led the team in the field and was responsible for deploying tags. Another team member collected biopsy samples, little pieces of skin and blubber, that tell sex information and look at genetic relatedness with other whales that are tagged. The team also included a photographer responsible for recording images of individual whale flukes. The flukes on humpback whales have unique coloring and can be identified much like a fingerprint.
The last member of the team was responsible for driving the small ridged hull inflatable boat the team used to get close enough to the whales to tag them. The team is specially permitted through NOAA’s National Marine Fisheries Service to conduct the tagging process, and their efforts are highly scrutinized and reviewed by both internal and external experts.
“We have to get between within two to four meters away from them to put the tags on,” Irvine says. “So we have to be way closer than anyone in the general public is allowed get to these whales in the process of our work.”
The tags are implanted high on the back of the whale, and they have a saltwater conductivity switch that senses when the tag is out of the water. Once the tag is out of the water the switch is triggered and begins transmitting its location. Their transmissions are tracked by satellites to track the whales when they come to the surface for air, but it’s not GPS. When a whale surfaces, the tags transmit a pitch recognized by the satellite, and researchers use the strength of the pitch to reconstruct the location and path of the transmissions.
The tags are implanted in the blubber layer, and basically work their way out like a sliver in your hand and drop to the ocean floor once their life cycle is complete. They cannot collect data for analysis until the tags have stopped transmitting which could be up to six months. The longest tag transmission on a humpback whale last year was 180 days. In 2014, researchers achieved their goal of tagging 20 humpback whales in Southeast. This year, the team fell three short of their goal of 20, tagging 17, but Irvine and his team still consider it a major success.
Irvine says so far, the biggest take away from the study is these mammals are amazing navigators. After starting their migration the whales all came out of the south end of Chatham Strait, and then turned toward Hawaii–in a straight line. Researchers don’t really understand how they do it, but the humpback whales are able to navigate a straight heading for over 3,000 miles. The whales travel in deep, open waters with no discernible landmarks or undersea ridges to follow, he says.
“Best guess is that they are using some sort of a magnetic navigation where they can actually sense the orientation of the earth’s magnetic field,” Irvine says. “It’s like a compass that can point toward magnetic north. The theory is they have something like that in their head.”
One tagged whale actually arrived in Hawaii after almost missing it entirely. The whale was holding a steady heading, but the heading was wrong and leading it about 150 miles to the south of the islands. Irvine says the whale eventually curved its course and managed to come right into the big island.
“Somehow it realized that and started making course adjustments,” he says. “They are able to navigate a straight heading, but then it also must have had some other way to assess information about where it was and make a course correction when it wasn’t going to arrive where it wanted to go.”
Understanding when humpback whales start to migrate and the routes they take could really benefit federal agencies entrusted with managing the species. For Irvine, crunching the numbers and data analysis to really use the information gathered is a perk of his job, although it could take up to two years before the team gets published results in a peer reviewed journal. Irvine has worked for the MMI since 1999, and loves attempting to describe the underlying reasons why whales act like they do.
“It’s that feeling of discovery, where we get to put these tags on and then we can go back to the office and check in on them,” Irvine says. “It’s like unwrapping a present every few days, you get to see something new.”
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