How many right whales are left?
This week, the National Oceanic and Atmospheric Administration (NOAA) announced that the population estimate (aka number alive) for North Atlantic right whales is 366 whales as of January 2019. The previous population estimate from January 2018 was 412 whales.
With a difference of 46 whales between estimates, I had some questions about how all of this works and what it means for North Atlantic right whales.
I turned to the experts and lucky for me, I have one on speed dial – WDC’s Executive Director, Regina Asmutis- Silvia! Regina has been working in right whale conservation for 30 years and also acts as the right whale policy lead for WDC. Regina is a pro when it comes to right whales and is also a pro at answering all of my questions!
Michelle: Since North Atlantic right whales live in the ocean, it has to be hard to be able to count them and estimate how many are left. How do scientists estimate how many right whales are left?
Regina: Great question. First of all, right whales are not tagged for tracking.
On land, researchers can sometimes put tracking collars on animals to follow and count how many are in an area, but that’s not an option for large whales. A collar around their tail stock could snag on fishing lines and create an entanglement hazard and tags which are implanted in whales only stay in temporarily. They also risk infecting the whale so are used very rarely.
Instead, individual whales are tracked by photographs taken during surveys. We can tell individual right whales apart based on a pattern of bumps on their heads that are a yellow-whitish color. Each whale has a unique pattern so when a photograph is taken, researchers know exactly who that whale is. Not every whale is seen during every survey but researchers have lots of data from many years of surveys so can predict how often an individual whale is likely to be seen each year and mathematically estimate the number of whales remaining in the population.
Think of it like looking at a classroom picture of students over 12 years of attending school. A student might miss picture day one year but is unlikely to miss it every year. If they are in the picture most years, then you can assume they are still attending that school. If multiple years go by where they are not in the picture, there’s a good chance they are no longer attending that school.
Michelle: It seems like counting whales would be easy because of their size, but their habitat and range make it much more of a challenge! The news items I have read said that the previous estimates for number of right whales were too high. How does that happen?
Regina: Going back to the school analogy, you need to review the picture every year to see if things changed so your results will vary every year. You may also know that some students moved away and are no longer at the school so you can remove them from your count.
Unfortunately when we are talking about removing right whales, it is because we know they died or were last seen in such poor physical condition that their chance of survival was low.
Since 2017, we know that at least 31 right whales died and another 11 were seriously injured and had a very low chance of survival. The difference in the counts comes from the individual right whales who died but didn’t wash up or were not last sighted in poor condition. They aren't being found in repeated surveys, but we didn't know for sure that they had died.
Michelle: It makes total sense that if we aren’t seeing all of the whales who are alive, we also aren’t seeing all of those who died! When I first read the differences in the numbers, I immediately opened the calculator on my phone to see that it was a difference of 46 whales!! Does that mean that 46 whales died between January 2018 and January 2019?
Regina: At least that many have died. Like I said, we absolutely know that over 40 are gone but how many over 40 is the big question. That’s why it’s important to keep the surveys going to get the pictures so we can get a best estimate of how many whales are left, who is left, and how many calves are being born.
Michelle: That’s a lot to keep track of! Why is the January 2019 estimate just being released at the end of 2020? Does this mean that the number of right whales could actually be lower than 366 for right now?
Regina: Yes it could be lower and the data from the North Atlantic Right Whale Consortium actually does show a lower estimate. The estimate is not significantly lower so we are hoping the 366 number is a fairly accurate estimate. As to why the 2019 estimates are only coming out now --- there are a lot of pictures to go through and it takes a while. Just like doing your taxes, you have to wait for the whole year to be over to have a final figure.
Michelle: Just like home improvement projects, it always takes longer than you think! We know that the top two threats to North Atlantic right whales are vessel strikes and entanglement in fishing gear. What can we all do to help the number of right whales go up instead of down?
Regina: First of all, you’re doing a lot as a supporter of WDC! Or I should say we are doing a lot with you and on your behalf and we are grateful for your help. WDC is an appointed member to the US Atlantic Large Whale Take Reduction Team through which we have forwarded proposals to the National Marine Fisheries Service to reduce the amount of vertical line in the water and reduce entanglement risk. Soon, the US National Marine Fisheries Service will be putting out a proposal for new regulations to reduce entanglements and we are going to ask you speak up and give right whales a voice by signing our response letter. Stay tuned!
WDC and its partners also filed a petition this summer demanding the federal government revise its ship strike speed rule to include new areas where right whales are now feeding and socializing.
We are also part of the Ropeless Consortium where scientists, fishermen, and conservation groups are working together to test new fishing gear that would reduce the amount of rope in the water, but still allow fishing in commercially valuable habitats.
But no worries, there is still more you can do! Right whales help us fight climate change, but their food is also impacted by changing water temperatures. Although it may seem an ocean away, the changing of your daily habits can help these whales.
Only idling your car for as much time as you need and only when you have to, recycling what is possible to recycle, saying no thanks to take out flatware or straws if you don’t need them, and powering down when possible. Plus powering down and going outside to enjoy nature is always a healthy choice right whales and for us!
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