In part one of our Gulf of Maine Humpback series , I spoke of how we use humpbacks’ readily identifiable natural markings to learn natural history information from migration routes to calving intervals. However, the discovery process is slow, and necessitates good and standardized scientific protocols. It’s this slow accumulation, processing and analyzing of data over decades that allows us to see trends and make new discoveries.
The process is also a collaborative one because whales are highly migratory. No one person or organization can be everywhere – so it’s only by pooling data together can we increase our knowledge of the life history of these highly migratory animals. This process leads to very busy field seasons in our North American (NA) office. WDCS NA curates a catalogue of 2,400 individual humpbacks within the Gulf of Maine, but this accounts for just a small part of the humpback in the North Atlantic.
The College of the Atlantic in Bar Harbor, Maine curates a catalogue much larger then our -about 7,000 individuals from the entire North Atlantic. So it literally takes researchers from around the world working together to learn about the movements of whales. You are probably saying to yourself right about now- “Gosh, there’s got to be an easier way”. Satellite tags are used to get see how whales migrate over longer times and distances, but it only tracks that one whale and only for about 15 months and getting the tag on the animal in the first place can be troublesome and stressful on the animal. Satellite tags can be a very useful tool in the research box, but they do have their limits can’t give you life history information, such as calving rates and life spans. There are also many welfare concerns surrounding their use and application, and their long-term effects on the individuals concerned.
Peter Stevick, from Allied Whale, gave a talk at this year’s Whale Watch Naturalist Workshop highlighting some of Allied Whales work. Here is some of what we know about North Atlantic humpback whales. Of these 7,000 individuals, 4,810 have been documented on one of the six different North Atlantic feeding grounds (Gulf of Maine, Gulf of St Lawrence, Newfound, Greenland, Iceland and Norway) whilst 2,250 individuals have been seen in multiple years. The longest time between sightings of an individual is 36 years. One individual was first sighted in 1976 in Puerto Rico and then again in 2009 off Newfoundland. Never in the 36 years in between do we have a recorded sighting of this individual. I think this is a great example of what we are up against while trying to study whales.
About 2,400 individual humpbacks have been sighted in the main breeding grounds – the West Indies (link to http://www2.wdcs.org/fieldblog/index.php?/archives/128-Humpbacks-in-the-Gulf-of-Maine.html) however, only 772 of these 2,400 have also need seen in one of the feeding grounds, 175 of them in the Gulf of Maine.
However, not all the whales seem to go to the West Indies. The West Indies seems to be more heavily used by humpbacks that feed in the western North Atlantic whilst there is still a chunk of the eastern North Atlantic humpbacks that we do not know where they go to breed. There is another breeding ground in the Cape Verde Islands, however it seems that Cape Verde Islands are utilized by only tiny percentage of the population. For example, this year of eight animals photographed in Cape Verde Islands, five had been documented there in prior years. But there are cases of eastern North Atlantic humpbacks being documented in the Cape Verde Islands – two from Norway, and one from Iceland.
There is also a small exchange of individuals between feeding grounds. For Gulf of Maine (GoM)– 56 individuals have also been sighted in Newfoundland and Gulf of St. Lawrence, while one individual from the GoM was sighting in Greenland. Particularly scary due to the fact that Greenland wants to start hunting humpbacks.
As for this year we have documented 112 known animals and 18 mothers so far this year. Of course this is the growing and reproducing part of the population so we pay special attention to who’s giving birth and how often. So for now we are out on the water working as hard as we can to document humpbacks within the Gulf of Maine –for science as well as conservation.
And there is no better of example of how photo-ID, whale watching, research, conservation and management intertwine than Tofu. Tofu was born in 2005, to Isthmus, she was the grandcalf of Orbit, a third generation of identifiable humpback whales in the Gulf of Maine.
On June 24, 2007, WDCS received a call from a whale watching boat reporting a dead humpback whale. We went out to investigate and tow the whale in for a necropsy. We were able to identify the whale as Tofu from a small area of skin on her flukes, on her otherwise skinless body. A quick look at our data showed a sighting of Tofu on June 15th. Further investigations from whale watching boats indicated Tofu was last seen alive on June 21st – given the times of the sighting and the discovery of her body- she was dead, at most, two and a half days.
As there were no external signs of injury on her, WDCS and the Stellwagen Bank National Marine Sanctuary towed her to Brewer’s Plymouth Marine to be hauled out, placed in a truck, and driven to a site for necropsy. The necropsy indicated she died from a vessel strike.
In the US, the Marine Mammal Protection Act includes a calculation for Potential Biological Removal (PBR). It is the number of animals that can be accidentally killed by human causes without harming the population level as a whole. For humpbacks in the Gulf of Maine, the number is three. Already that spring, two other humpbacks had been killed by vessel strikes. When PBR is met or exceeded, management actions must be considered.
From Tofu’s discovery to necropsy took three days and involved more than 50 people - from whale watching captains to Federal Agencies and everything in between. Knowing who this whale was, and how she died, mattered, not just to WDCS but to the conservation of the entire Gulf of Maine humpback population.
Tofu’s skeleton was sent to the Sea Coast Science Center in New Hampshire (US). She leaves a legacy exemplifying the threats whales continue to face at our hands and why the sighting of that one whale matters to the future of an entire population. On-the-water research is expensive and time consuming. WDCS’s most recent research trip in the Gulf of Maine lasted over 13 hours at a cost of more than $500USD in boat time alone. But a small price to pay to ensure the future of a population.