How Do Cruise Ships Avoid Whales?

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Often the first creatures we think about in the open ocean are whales. Different species are found around the world at different times of the year, and their migration paths have them travelling many thousands of miles every year. In fact, many whales seem to prefer the same weather cruise ships do, following the summer weather from the Northern hemisphere to the Southern hemisphere, and back again.

Our guests and crew care deeply for the environment we sail in, and for the wildlife in the ocean. Part of what makes a cruise vacation so special is getting to experience the amazing ocean world for a short time, and if we’re lucky, seeing some of the creatures that live there! However having a giant ship sailing through your home isn’t exactly natural, so we take steps to ensure we leave these sea creatures and their habitat as undisturbed as possible.

Cruise Ships vs Whales

Unfortunately, there are regular stories of whales that have been injured or killed following a collision with a ship – since 1975, there have been 80 confirmed contacts (NOAA – hawaiihumpbackwhale.noaa.gov) between humpback whales and a vessel around Hawaii alone, and more contacts may go unreported. Whales that are still endangered such as the North-Atlantic and Southern Right Whale often don’t react to ships in the area, and move very slowly, putting them at higher risk of a collision. Many countries will conduct an autopsy to find the cause of death, and in some cases the animal was sick or injured prior to the collision. So what is being done to prevent these accidents?

Right Whales dive underwater for up to 40 minutes at a time, but only swim around 10 mph (16kph). Even weighing up to 60 tonnes, they’re no match for a ship weighing over 30,000 tonnes. This is why their habitats are so closely guarded from shipping traffic.

One of the challenges that cruise ships face with whales is spotting them in the first place. On a sunny day, with calm seas, the spout of a whale can be seen for several miles. This will give plenty of time to track their travel path, and change the course of the vessel to avoid them. Some of the radar sets used on cruise ships are sensitive enough to pick up the cloud of water from the spout, although this will only be seen for a very short time. With several people keeping a constant watch ahead of the ship, we stand the best chance of seeing whales. But at night, or in poor weather, whales are difficult to see even at a closer distance. In these cases, taking preventative action is our best chance at protecting them.

Whale Protection Areas

Countries around the world have identified areas of their waters that are critical to the breeding, migration or feeding of whale species, and applied special precautions to these areas. In New Zealand, one of these areas can be found in the Hauraki Gulf, from Auckland all the way out to the Coromandel Peninsula (poal.co.nz). In the United States, areas on both the West and East coasts (noaa.gov/sanctuaries) have been identified for the preservation of the Humpback whale, once one of the most endangered whale species, and other species that are still on the  International Union for Conservation of Nature ‘Red List’ (iucnredlist.org).

Hauraki Gulf Transit Protocol
Hauraki Gulf Transit Protocol sets a speed limit of 10 knots for commercial shipping. (poal.co.nz)

These areas afford protection to the whales that rely on them through a variety of means. One way whales are protected is through the use of speed restrictions – the slower a ship goes, the better chance a whale has of avoiding it. Different restrictions may be imposed for different whale species, depending on how fast the whales can actually swim! For example humpback whales are relatively fast – the Humpback Whale Sanctuary surrounding Hawaii recommends a speed of 13 knots or less (around 25km/h). The Bryde’s Whale, protected in New Zealand’s Hauraki Gulf, is slower, and ships are requested to sail at 10 knots or less.

Whale Reporting

Another way we help protect whales is through vessel reporting schemes. Countries commit resources to tracking where whales are found, and pass this information to the shipping traffic in the area. This is often a partnership between port facilities, vessel traffic schemes and a national environmental body. When ships report whale activity, it allows better tracking of their population and movement. Using this information, speed restrictions can be tailored to the actual area whales are found, providing an effective balance between the economic constraints of the shipping industry, and ensuring the safest habitat for the local whale population.

Ships are generally unable to ‘look ahead’ under the surface of the ocean, relying on the navigation charts published by each country’s government. Besides submarines and some specialised research vessels, it is rare for ships to have their own sonar to see what lies ahead under water. Every ship will have an echo sounder that measures the depth of water beneath it, but building an image of the ocean ahead of the ship is much more complex. Systems that do exist have limited range, reliable up to only 500 meters. Even at slow speeds this gives the ship less than a minute to detect an object, determine what it is and where it is going,  and alter course to avoid it. A turn made this quickly could cause the ship to lean over to one side, causing injuries among the guests and crew.

Ships Propeller
A ship’s propeller creates a lot of noise as it pushes through the water – but sometimes this noise can be masked by the ship itself. (CC0)

One problem whales have with ships around them is the ‘acoustic disturbance’ introduced by a ship. With our engines running in the bottom of the ship, and our propellers churning up the water, we can be pretty noisy! In some directions around the ship this is the case, and our noise can interfere with the ‘sonar’ echo location used by whales and dolphins to navigate and communicate. However in other directions, the noise from the ship can be masked by the ship’s hull shape, or our movement through the water. This can make it difficult for a whale to sense our approach, so it becomes more important that we are travelling slowly and giving them (and us!) enough time to safely react.

I remember one occasion when sailing around Alaska – it was right before sunset, the sky was lit with amazing colours, and we encountered hundreds of whales all around us! We had extra lookouts on the bridge to keep track of them all, and had reduced our speed significantly so we can safely avoid any we might come close to. Having the sun lower in the sky makes it easier to see the clouds of water as they spout off. At one point, I was torn between watching a humpback whale breaching – leaping from the water, and falling back in with a mighty splash, and another whale that was spotted coming close on the other side of the ship! 

Unfortunately the second whale kept coming closer all the time. We started a fast turn to avoid it, and I’ll never forget seeing the whale finally sense the ship ahead of it – you could tell how startled it was, trying to back away with it’s long pectoral fins working overtime! We safely passed by with only about 30 meters clearance, but I bet that poor whale needed a few deep breaths to calm down… I know I did!

Whale breaching with fins.
The shape of a whale’s pectoral fin helps us identify the species, so we can better predict their behaviour. (CC0)

Protecting Whales Through Research

Research is constantly being undertaken to better understand whale behaviour, their migration and breeding patterns, and how we can best support them. The Cruise Lines International Association (cruiseforward.org), to which most of cruise lines worldwide belong, supports this research, and has provided training developed by Holland America Line to all its members. This training is targeted at Deck Officers and lookouts, giving information on whale identification and avoidance. By better understanding whale behaviour, when they are spotted the watchkeeping officer can make an informed decision about how to best react. Of course, whales have a mind of their own too, so even with the best information their actions cannot always be anticipated.

By taking these precautions and carefully managing the protected areas that are so important to the migration, breeding and feeding of whales, we strive to not only maintain the current population and habitat of these amazing creatures, but to improve on it. Through these and other whale conservation measures, including international action against commercial whaling, many populations of whale species have been brought back from being ‘endangered’ – the humpback whale is now listed as ‘Least Concern’ by the International Union for Conservation of Nature (IUCN.org). As an industry we will continue to build on this progress, ensuring future generations can enjoy a beautiful cruise vacation as we do today.

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