Fragile friends

Jun 22, 2017 Environment ,General Interest

Encounters with marine mammals are sometimes unavoidable, but you can take steps to coexist in harmony, writes John Tucker.

Whispers II was surfing under kite at 15 knots when she hit the whale. Two of our sons were aboard, racing from Wellington to Sydney on the first leg of the 1994 Tasman Triangle. Ben and Josh both still rate this as one of the more dramatic moments of their 100,000-plus sea-miles.

“There was no warning,” says Ben. “It just appeared in a trough. We crashed to an abrupt halt. There was blood in the water, but by the time we’d finished assessing our own damage there was no sign of any stricken whale.”

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Certainly it was not the sort of human-whale interaction that anyone would wish for, and the protocols that have been set in place for approaching any marine mammal do their best to prevent such contact. On this occasion the Whispers II crew got off lightly – she was a solidly-built Spencer. But one can only guess at the distress for the unsuspecting whale. And Josh tells me that he now always sleeps feet forward, when racing, to save a potential broken neck.

Whale strikes occur more frequently than you’d expect. In the Hauraki Gulf alone, nearly half of the 42 known Bryde’s whale deaths between 1996 and 2012 resulted from collisions. Considering that there are now fewer than 200 of this whale species left in New Zealand waters, it may not be long before they are just a memory for Kiwi boaties.

For a ‘logging’ whale or dolphin – moving slowly through the water, just awash, with half its brain catnapping – a fast-moving vessel with a poor lookout may be as deadly as a Japanese harpoon. Race yachts are as formidable as launches, moving silently through the water. Some experts suggest the
best way of fore-warning a whale of an approaching vessel is to leave an echo-sounder turned on.

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And it’s good to know that there’s a team of dedicated DOC specialists who will always be grateful to hear of any injured whale, dolphin or seal which may need attention (contact the team on the free hotline: 0800 362 468).

Whales and dolphins need as much sleep as the average human – about eight hours a day. But they also need to only open their blowholes above the surface while maintaining a breathing rhythm. Researchers have discovered that they sleep while logging, shutting down one side of their brain (and its opposite eye) for around two hours at a time before alternating with the other half-brain and eye.

During this catnapping period, the breathing rate slows, and the individual maintains a rather reduced state of awareness – hence its vulnerability. I well remember a big bull sperm whale in Cook Strait which showed no signs of noticing us as we idled along on a parallel course – some 70m distant – for a full 20
minutes before resuming our journey.

Female cetaceans with newborns must keep constantly on the move to draft their calves behind in their slipstream. For the first few weeks after birth these youngsters lack the blubber they need for buoyancy, and will drown unless they are kept moving.

It is known as an echelon formation and places an extra energy and vigilance burden on the mother while catnapping. Seals can be seen napping afloat too – they are a comical and not uncommon sight these days, lying on their backs with their flippers in the air. But as they spend their best sleeping time
ashore, they are far more aware of any surrounding dangers than a logging whale.

With numbers of boats and whales steadily increasing in recent decades, interaction between humans and all these marine mammals has become more commonplace. Encounters are always thrill, no matter how often we see them, but they potentially come at a cost to the creatures whose space we are invading.

Commercial tourism operators work to a clearly defined code of practice (their livelihood depends on keeping the relationship comfortable), but recreational boaties are often ignorant of the distress they may be causing when they see a chance to get up close and personal on the water. One of the unseen
issues is underwater noise.

Scientists have recently discovered numbers of deaf whales near significant shipping lanes. I found this fact hard to believe until recently, when we rented a temporary mooring near Picton. The volume of underwater noise from each passing ferry – transmitted directly to our uninsulated hull through a kilometre of seawater, is quite staggering.

The much higher pitch of propeller noise from early morning water taxis also sets off enough noise to wake me before my alarm clock. Lying in my bunk, I have become acutely aware of what it must be like
to be a seal or dolphin surrounded by a cacophony of propellers.

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Marine mammals communicate at a variety of frequencies, with clicks, whistles and song, transmitted through seawater over much greater distances than they would through the air. They also have their own agendas, just like us. They don’t like to be bothered by noisy paparazzi during a meal, especially when that meal happens to be a school of fish which is equally bothered by churning water and screaming propellers.

The fact is that these creatures lead busy lives of their own, and will react to humans accordingly. Some will attempt to avoid interaction while others may seek it out. For example, a right whale cow feeding her calf will be highly upset by any small craft invading her comfort zone, but a travelling pod of dolphins may decide to divert towards a similar vessel to enjoy surfing on a pressure wave.

Likewise, a sleepy seal may become agitated by an approaching group of kayaks, while a lonely humpback bull may be aroused by the sight of a deliciously rounded yacht-bottom in his territory.

There are now so many humans and marine mammals busily using our coastal waters that interaction is becoming an issue. Crowds don’t tolerate a pitch-invasion during a cricket match or a streaker during a rugby test. It is equally unacceptable for a PWC or runabout to veer into a pod of travelling whales or feeding dolphins.

Sensible guidelines were drawn up some years ago, regarding acceptable approaches and proximities to different types of marine mammal. These guidelines are now law, taking the guesswork out of those situations which can often arise during the excitement of a whale-sighting. They apply equally to recreational and commercial vessels, with huge fines to give them teeth.

Whale-watching skippers know how to interpret the surface activity behaviour – body language – of these animals. They need their passengers to get the best bang for their buck, so they know that a humpback is likely to reduce its spectacular breaching if a vessel approaches within 300m, and that a sperm whale is unlikely to show its wonderful tail-flukes if it becomes alarmed.

These skippers also know that tail-slapping killer whales are showing annoyance, and unless left in peace they may well move away to a less disturbed hunting ground in future, depriving the whale-watchers of repeated sightings. For this reason, the commercial operators have strong long-term incentives to operate within the best-practice protocols.

In a nutshell, the law states that nobody may drive a boat in a manner which cuts off the path of any whale or dolphin, or causes scattering or separation of individuals within a pod. This means approaching and leaving slowly (at no-wake speed – under 5 knots within 300m) from either behind or the side, to
no closer than 50m for whales and 20m of seals hauled out on shore (where they are less confident).

Females with calves have extra protection – 200m is the closest allowable approach. And if there is more than one vessel involved, coordination is necessary to avoid confusion to the animals. There is a strict three-boat rule around marine mammals – any other vessels will have to wait outside the 300m zone. It’s first three in, first served, so if there are a lot of boats waiting it’s polite to limit your time enjoying them.

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Experts recommend that, while enjoying the spectacle, skippers are best to idle their engines, preferably in gear, to avoid sudden gear-change noises or erratic changes of speed and direction. Reversing is a no-no. As well as being noisier, propeller strikes are more likely reversing towards a dolphin or seal.

Some of the regulations are common-sense. ‘No rubbish may be discarded near marine mammals.’ I would hope no rubbish will be discarded anywhere at sea! It is also against the law to feed these
creatures, so avoid the temptation to toss them your unused bait.

Other regulations are less intuitive. Swimming within 100m of any whale (including pilot whales and killer whales) is totally prohibited, although it is okay to swim with dolphins and seals as long as no calves are present. The best rule of thumb when judging whether a youngster is still a calf is to compare its size against an adult. If it is half the size or smaller, stay out of the water.

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The most exhilarating encounters are often the unexpected ones. We have had our share aboard our gaff ketch – the big mischievous bull humpbacks that have caught us unawares by breaching right alongside to shower us with spray both at Mururoa and the Isle of Pines, and the big fin whale that poked its head up directly alongside to inspect our cockpit, one evening in the Southern Ocean. These are the rewards of patience.