Showing posts with label #14. Show all posts
Showing posts with label #14. Show all posts

9/11/11

#14: The Quest for Whale Blow, Chapter 1: The Adventure Begins

One of our newest research projects is a pilot study to see if it is possible to collect respiratory vapor ("blow") from free-swimming North Atlantic right whales, and then to see if we can measure stress hormones in it.

But first: why are we trying to measure hormones in whale blow? To give a little background, one of the most urgent needs in marine mammal research today (in my opinion, anyway) is that we really need a good way of measuring stress hormones in free-swimming whales. I've been measuring stress hormones in terrestrial wildlife for most of my career, and time and again I've found that that if you have a good method of measuring stress hormones, you have a good chance of figuring out whether or not certain human activities are seriously affecting the animals.
For example, whales worldwide are being affected these days by a huge variety of disturbances, ranging from noise (shipping traffic, sonar, seismic exploration), to global climate change, to direct physical effects like net entanglement and ship strikes. Some of these disturbances are obviously bad for the animals. An entangled whale, for example, is very obviously in trouble. But what about the disturbances that have subtler effects? It's not always so easy to figure out whether, or how much, certain disturbances might be affecting the animals. Take shipping noise, for example. Suppose a population of whales is subjected so much shipping noise that (say) the whales fall silent, apparently unable to hear each other; or maybe they move away, leaving a preferred feeding ground and moving to a less preferred feeding ground. Those responses might look rather minor. But sometimes the animals actually turn to be highly stressed by such impacts, to such a degree that their health and reproduction starts to suffer. Eventually, the whole population can start to go downhill.

The good news is that these subtle effects are very often detectable early on, via elevations in the animals' stress hormones. So, if we could develop a way of measuring stress hormones in whales, we could potentially finally have a good method to detect, assess, and hopefully ameliorate, the stressful impacts of human activities - before the impacts get too severe.
So, that's why we want to be able to measure stress hormones in whales. There's a fundamental problem, though: Most hormone techniques require blood samples, and it's basically impossible to get a blood sample from free-swimming whale. So we have to try to get some other kind of sample from the whale instead.


A North Atlantic right whale's distinctive V-shaped blow.
Photo: Jessica Taylor

We've already found that we can measure stress hormones very well in whale feces, and we have several other research projects focused on fecal stress hormones. But unfortunately, not all whales are thoughtful enough to provide a fecal sample when we want one! Enter respiratory sampling. If you spend any amount of time watching large whales, you'll know that every whale, every time it surfaces, produce a big, puffy cloud of respiratory vapor. When you're watching a whale, usually it does not happen to produce a fecal sample when you're nearby, but it always blows. Repeatedly. In fact, these "blow" clouds are so big and visible that they're often how we spot and find the whale in the first place (as in, "Thar she blows!"). A few researchers have already succeeded in collecting tiny amounts of blow vapor, and one of our colleagues even found some hormones (testosterone and progesterone) in a few of her blow samples.

What we want to do now is develop a method to collect larger volumes of blow, enough so that we could try to measure several different hormones at once - including the first-ever attempt to measure stress hormones in whale blow.

-Kathleen Hunt

ps- stay tuned for Chapter 2!

9/5/10

#14 Right Whale Numbers Still Low

R/V Nereid on a calm day in the Bay of Fundy

Despite our initial excitement after our survey on August 27 that suggested the right whales had arrived into the Bay of Fundy after a slow start, it appears that this influx of animals was short-lived. After three days of extensive surveys using two boats on August 29, 30, and 31, only ~17 individuals were sighted. Few of these individuals matched the ~18 whales sighted by the Nereid on August 27 yet the area surveyed over those latter days in August certainly included the area surveyed on the 27th. We are perplexed by the low numbers of right whales and what appears to be substantial movement by individuals in and out of the Bay. Last year during the month of August we saw at least 79 individuals not including calves of the year (data is still in progress). This year we have only had 32 individuals (not including calves) so the change is dramatic.

Though we don't know the reason for this reduced number, some ideas have come to mind. First, for the first time ever in our 30 years of surveys here, we appear to have a number of sperm whales sticking around in the Bay - as many as seven individuals were seen on August 29 by our two vessels. Also, whale watch boats in the area have been seeing them throughout the month. When we put our hydrophone in, the sound of clicking sperm whales was quite loud. It could be that right whales do not like this sound (see video below).



Audio clip of Sperm whale clicks recorded by Dr. Susan Parks (Environmental Acoustic Program, Penn State University) and her PhD student Jenny Tennenssen (Ecology Program, Penn State University) while on the R/V Callisto.
*Note - audio was dubbed to the video for visual effect, clicks can only be heard underwater.

Another possibility is that the food resource has not set up well this year and thus, the copepod density is not high enough for the right whales to stick around.

We are hoping that Hurricane Earl which passed through the region on Saturday morning could shift things around and entice the right whales back into the Bay. Once the seas and winds calm down, we will be heading back into the Bay to see who we find.