UNDER SIEGE

The Whales in Our Waters

A. RESOURCE COMPETITION

Predators need prey — it’s that simple. The largest whales eat massive quantities: some baleen whales vacuum up four tonnes a day of krill and other organisms for which there is little human appetite. For them, environmental degradation is the danger: rising water temperatures and pollution are shrinking krill stocks. Many toothed whale species, on the other hand, have evolved to be specialized consumers of specific prey species. For these populations, when prey declines — as it has around the world because of overfishing, habitat decline and pollution — whale populations suffer too. On Canada’s Pacific coast, resident killer whales consume salmon, whose populations are a fraction of historical levels, well below 10 per cent in certain areas even as human consumption increases. In recent years, the Canadian government has tried to conserve whale populations by controlling the commercial fishery, that is, by limiting human catch in vulnerable areas.

B. WATER POLLUTION

Because they are so high in the food chain, whales consume and bioaccumulate massive quantities of toxins. Countless studies have found that whales consistently show high levels of poison in their systems, in quantities that damage their reproductive and developmental processes and immune systems (leaving them vulnerable to diseases and parasites).

Common chemicals include PCBS (now banned in many places but still abundant), PBDES (flame retardants), dioxins (highly toxic industrial by-products) and furans (nasty carcinogens). Oil spills too are a serious threat, as they are not perceived by the whales to be a danger: not only is oil extremely toxic when consumed, the oil also damages baleen in some species, preventing them from getting nutrition thereafter. Another danger is waste dumping, which transfers parasites from humans and terrestrial animals into the sea, introducing a whole other biohazard.

C. NOISE POLLUTION

Often called the “silent world,” ocean waters are anything but. Even down deep, they are noisy and getting noisier. The problem for whales is that sound is central to their most essential functions: navigating, feeding, communicating, reproducing and evading danger. Disrupt their acoustic environment and whales suffer. As a long-lived species, they are unable to adapt rapidly enough to survive.

Sources of noise pollution include shipping, coastal industry and cities, seismic exploration, sonar and deepwater drilling. It is not a local issue, as sound travels great distances under water: a seismic airgun used in oil exploration is “audible” to a whale 2,500 kilometres away. A small underwater explosion can harm sea life for kilometres in every direction.

The effects are grim: internal injuries, cellular damage, fatal disorientation, deafness and death. Stress impacts include slower growth, weaker immune response, increasing parasites, declining reproductive rates and, therefore, diminishing numbers.

D. SHIP STRIKES

Speed kills. It is as simple as that. Collisions between whales and ships first became an issue late in the 1800s when ships started to reach speeds above 13 knots (24 km/h). It wasn’t until the 1950s, with faster and larger ships — and more of them — that the problem was recognized, though little was done. Today it is a crisis, with most fatal or serious whale injuries caused by ships 80 metres and more in length and travelling at speeds of at least 14 knots.

While researchers seek technological solutions for the future, the most effective answer is keeping them apart — that is, by restricting shipping traffic. When this is not possible, limiting ship speeds to 10 knots reduces collisions to near zero. This is now the policy enforced in the St. Lawrence River near Anticosti Island between May and November, when right and other whales gather there.

E. ENTANGLEMENT In

the last few years, Canadians have learned about the problem of entanglement as heart-wrenching incidents have hit the news. It is a growing problem: the International Whaling Commission estimates more than 300,000 whales and dolphins die annually from entanglement with fishing ropes. Countless more are injured and maimed, enduring great suffering and slow deaths. It is also a human safety issue, as was learned in 2017 when a whale rescuer died in the Gulf of St. Lawrence: dealing with distressed wild animals this massive is tremendously risky for rescuers.

Proposed solutions often focus on changes to equipment. Developing and using ropes, lines and nets with lower breaking strength (still well within the range needed for fishing) could reduce life-threatening entanglements for large whales. And innovators in Australia have devised GPS- and Bluetooth-enabled lobster traps that do not require any ropes. In the meantime, funding and training for whale rescue teams is desperately needed.