Things that go bump in the night

by oceansadminHabitat, Human Impacts, PopulationsPosted on No Comments
A killer whale surfs the bow wave a cruise ship in Johnstone Strait.

When ships strike whales, the whale generally loses. People must wonder why scientists treat this issue like it’s some great mystery that’s difficult to quantify and even more difficult to solve.  After all, hitting a large whale must be like hitting a moose with your car.  Right?  So fixing the problem must be as easy as searching the shipping lanes for marine roadkill, and making shippers slow down.

This Pacific white-sided dolphin has a huge gouge near its tail flukes. Was it caused by fishing gear, a propeller, or something else?

In fact, assessing the extent of ship strike mortality is incredibly challenging.  Sure, vessel operators may underreport whale strikes, but in fairness, with very large, fast ships, collisions may go entirely unnoticed.  A typical cruise ship may weigh 50,000 tonnes.  A typical fin whale may weigh 50 tonnes.  Yes, that’s a lot of whale, but it could be analogous to hitting a 2kg animal with a 2,000 kg SUV.  Except that the ship strike can happen in a lurching, heaving sea, with the ship moving and whale surfacing and diving in three dimensions.  And when whales die, whether from human or natural causes, only a trivial fraction of carcasses are recovered. To us, it’s a wonder that this issue is reported as frequently as it is, given all the odds against detecting the problem in the first place.

Fortunately for the whales, this issue is receiving a lot of scientific and management attention.  Off the east coast of the US, scientists have built a convincing case that the critically endangered North Atlantic right whale population cannot withstand the death of even one individual annually from ship strikes, so tremendous bilateral efforts have been made to separate ships from whales in important habitats in both the US and Canada.  Recently, regulators have started issuing speeding tickets for mariners who violate the rules designed to protect the whales.

In 2010, we partnered with Dr Patrick O’Hara (Environment Canada) to conduct a risk assessment to identify where ship strikes may be an issue for fin, humpback and killer whales in BC.  A risk assessment involves two main components:  (a) trying to estimate the likelihood of a thing (usually bad) occurring; and (b) predicting the consequences if it does.  Put simply, we mapped where ships and whales are likely to overlap.

This overlap analysis actually tells us three things:

1. oil spill risk:  Shipping intensity seems like a good proxy to use for oil spill risk.  The probability of an oil spill happening is low, but if it happens, it can be catastrophic to individuals and populations.

2. ship strike:  again, the probability of it happening is low, but it can be fatal.  And if it happens often enough, it can be damaging to populations.  Our work is showing that fin whales in BC cannot tolerate the removal of more than a few individuals per year.  Given the occasional, high-profile examples of ship strikes involving fin whales worldwide, we wonder how much of an underestimate these reports represent.

Predicted areas of overlap between shipping activity and humpback whales in BC (from Williams & O'Hara 2010).

3. chronic ocean noise:  high noise levels are a sure thing in a shipping lane, and we’re just beginning to quantify the effects on marine mammal habitats, individuals and populations.  Our colleagues are documenting similar effects of noise on non-mammalian wildlife like squid and fish.  So, we believe that even if a ship doesn’t strike a whale, this “overlap analysis” can still tell us where important whale habitats are likely to be degraded by chronic ocean noise.  Our work has shown that repeated disturbance by boats can disrupt the feeding behaviour of killer whales, and our new research (with Cornell University’s Bioacoustics Research Program and the Sea Mammal Research Unit at the University of St Andrews) is modelling how much acoustic space whales lose from shipping noise.

REMEMBER, THE CAMERA ADDS 10 TONNES…

by oceansadminAcoustics, Dolphins, Ecosystems, Habitat, Whales, Women in SciencePosted on 2 Comments

At New Year’s, we all make resolutions about diet. But we’ve got nothing on Pacific humpback whales, which are currently on their mating and calving grounds in Hawaii and Mexico. During this time, they go weeks or months without eating at all. BC waters provide important habitat for these highly migratory animals. When they’re here in summer, they only have a few months to put on all the fat reserves they need to migrate over 4000km (each way) across the ocean, calve, mate, nurse their calves and return to BC to start the cycle all over again. From our perspective, this creates a sense of responsibility for Canadian resource management: human activities that degrade the quality of feeding habitat in BC waters carries consequences that affect the whales throughout the rest of their range.

WE LOVE THE BBC SERIES, “NATURE’S GREAT EVENTS“.

Humpback whales eat a lot, and they accomplish all of this without teeth.  How do they do that?  An incredibly gifted filmmaker, Shane Moore shot this extraordinary footage for the BBC that shows the northeast Pacific ecosystem much better than we ever could describe in words (although Sir David Attenborough comes a close second to the whales themselves). [Please note:  BBC put this link on youtube, but they’ve also put some other amazing footage on their site, which we encourage you to see.] Enough lead-in.  Check out this frenzy of seabirds, herring and whales:

MEANWHILE, BACK AT THE RANCH…

Of course, not all marine mammals migrate. Some, like the Pacific white-sided dolphins we study, have been seen in our study area every month of the year.  Dolphins, including the killer whale (the largest member of the dolphin family) do not fast over the winter months. Instead, they eat like we do — constantly.  And dolphins and killer whales both have teeth, and big brains, to help them come up with clever ways to find their prey.

The following video shows dolphins and killer whales hunting.  You might want to watch this on your own before deciding whether it’s appropriate for younger viewers.  [Note.  We collect our photographs and video under a research permit.  We learn a lot through photo-ID, but we are obviously not filmmakers.]

[vsw id=”14224604″ source=”vimeo” width=”600″ height=”400″ autoplay=”no”]

Listen.  Everybody’s gotta eat.  The whales aren’t doing this because they hate dolphins.  They’re doing this because, like dolphins, us and all organisms that can’t feed themselves through photosynthesis, whales need to eat to survive.  Our colleague, Jackie Hildering, recently witnessed a similar event.

A lot of our work aims to estimate abundance of whales, dolphins and other top predators, because we want to see ecosystem-based fishery management practices that ensure that nutritional needs of marine wildlife are taken into consideration when setting fishing quotas.  But lately, we’re growing concerned about the potential for underwater noise to mask the ability of a whale or dolphin to find its prey or detect when predators are nearby.  Going back to Shane Moore’s tremendous BBC footage, a frenzy like that must make some noise that a humpback whale could hear and use to locate a school of fish.  OK.  We’re guessing at that — it hasn’t been proven scientifically (although this is a research question we’d love to take on).  Our colleagues have shown convincingly that killer whales use sound to find and locate their prey, so it’s not rocket science to guess that human-caused noise can disrupt that sensitive acoustic system.

OK.  Maybe we shouldn’t make this all about human activities.  Maybe you should forget the text, watch that BBC footage again and just appreciate, as we do, how neat these animals are.

It’s the whale equivalent of Park Place and Boardwalk…

by oceansadminHabitatPosted on No Comments
Not all ocean habitat is created equal. We study killer whales at extraordinary beaches that whales use for rubbing. For most other populations, we use spatial statistical models to identify areas that whales and dolphins use more often than you'd expect from chance alone.

A lot of our time is spent looking for whales and dolphins.  When we find them, we assume that the animals are in a particular place for a good reason.  The area that the animals occupy is their habitat, and much of our scientific research aims to identify why animals are found in some areas and not others. The aim is to identify the kind of habitat that species prefer, and to conduct science that lends support for legal protection of important habitats for whales, dolphins and porpoise.  Sometimes this is as coarse as simply animal mapping distribution from surveys.  In really well-studied species like killer whales, our work can get quite narrowly focused.

LOCATION, LOCATION, LOCATION

Imagine a killer whale’s behaviour as providing a Yelp review of restaurants.  If a whale is always feeding whenever you see it in a particular spot, then that spot can be thought of as a “restaurant” that gets 5 stars.  If a whale is never seen feeding in a particular area, it gets 0 stars.  Our study mapped feeding preferences of endangered southern resident killer whales in the waters around the San Juan Islands.  [For the locals, it turns out the southside received the 5 star review.  Not very surprising, I guess.  The area’s called Salmon Bank for a reason.]  But the take-home message is that preferred feeding habitats can be targeted to receive priority for habitat protection and considered in marine spatial planning initiatives.  Our work has convinced us that despite their wide-ranging and migratory lifestyles, whales, dolphins and porpoises can benefit from marine protected areas.

We’ve found that critical habitat for whales can be a mixed blessing of sorts.  Whales may aggregate in certain areas because they are reliable places to find food and mates, but this tendency to aggregate may lend whales surprisingly vulnerable to catastrophic events like oil spill.

Ships are loud

by oceansadminAcoustics, Habitat, Human ImpactsPosted on No Comments

Check out what a humpback whale hears as a ship steams around Vancouver Island:

In partnership with acousticians and engineers at Cornell University’s Bioacoustics Research Program, we’ve deployed a number of hydrophones to measure underwater shipping noise in BC. Cornell’s Dimitri Ponirakis produced this amazing animation based on our data to illustrate what a humpback whale hears as a ship steams around Vancouver Island.

Humpback whales rely on sound: they make coordinated feeding calls when bubble-net feeding, and their songs on the mating and calving grounds are among the most complex in the animal kingdom.