As the annual humpback whale migration is underway with thousands of whales passing by the Australian coast, there are reports of dolphins joining the mass movement.

But this isn’t a one off. In fact, our new study, published today in Discover Animals, shows interspecies interactions between dolphins and whales are widespread and frequent around the world.

An astonishing interaction

There have been several reports of whale and dolphin interaction in the past.

One that astonished the public back in 2004 featured a humpback whale in Hawaii repeatedly lifting a bottlenose dolphin on its head.

Researchers suggested such close contact between whales and dolphins is likely very rare – and maybe related to care giving.

But other forms of interactions resembling joint feeding, play and harassment are now being frequently documented thanks to drone technology. Many are also featured on social media.

A ‘whale’s-eye view’ of the world

For our new study, we undertook an analysis of 199 independent whale-dolphin interaction events involving 19 different species. These interactions spanned two decades and occurred across 17 countries.

We drew from social media platforms – such as Facebook, YouTube and Instagram – and footage contributed by citizens to get a variety of observations.

Each entry was carefully reviewed to identify the species involved, validate the interaction and categorise behaviours. Two additional cases came from camera tags attached to humpback whales. These offered an underwater “whale’s-eye view” of their encounters with dolphins.

We categorised behaviours such as rolling, tail slaps, bow riding, and rubbing, and classified dolphin positions relative to whale body parts such as head, flank and tail fluke.

Having fun or fighting?

The study contradicted earlier assumptions that interspecies interactions between dolphins and whales are very rare.

The most common interaction was dolphins swimming near the whale’s head (akin to bow riding). This accounted for 80% of observed dolphin positions. Humpback whales were the most involved whale species, while bottlenose dolphins led the dolphin side.

Based on videos we analysed, dolphins initiated most interactions through bow riding, swimming in formation, or even touching whales.

In more than one-quarter of the events, the whales responded in seemingly similar ways. For example, humpback whales often rolled, exposed their bellies, or gently turned toward dolphins.

Tail slaps and other signs of distress or aggression were rare (roughly 5% of cases).

As a result of this, we classified more than one-third of all interactions between humpback whales and dolphins as positive or possible social play.

The two camera-tag videos revealed previously undocumented interaction. Dolphins were observed following humpback whales not only at the surface but down to the ocean floor. They maintained eye contact or even touched the whales’ head – suggesting intentional, possibly social, engagement.

Reflecting advanced emotional capabilities

The findings reshape our understanding of how social marine mammals interact across species. They suggest interspecies interaction among marine mammals may be far more prevalent and complex than previously believed.

Dolphins may seek out whales as companions for stimulation, play or even courtship-like behaviour. Meanwhile, certain whale species, particularly humpback whales, may not only tolerate but also engage with dolphins in a social capacity.

This interspecies dynamic adds a new dimension to marine mammal social ecology and could point to cultural elements in whale and dolphin societies. The playfulness, cooperation and apparent enjoyment observed in many interactions reflect advanced cognitive and emotional capabilities.

The study also demonstrates the power of new technologies and community science. Social media and drones proved invaluable for collecting a range of diverse behavioural data that traditional surveys might miss.

Social media data has limitations, such as geographic and observer bias caused by different angles, heights, equipment and frequency of use of social media. But it does complement other data and helps uncover previously unknown behaviours.

Whales and dolphins don’t just coexist but also seek each other out. Future studies incorporating acoustic recordings and longer observation periods could further unravel the motivations and meanings behind these fascinating encounters.

Olaf Meynecke, Research Fellow in Marine Science and Manager Whales & Climate Program, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Top header image: Michael Dawes/Flickr

Whale-watchers off the coast of California were treated to an extra special sighting last week when they came across an all-white orca calf swimming alongside its family near Newport Harbour. After receiving reports of the unusual find from a Long Beach tour operator, the team from whale-watching company Newport Coastal Adventure scrambled to get to the sighting. Drone operator Charley Fitzwilliam was onboard to capture some wonderful aerial footage of the encounter:

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"On just a few hours’ notice, we loaded three boats for a special trip and drove 50 miles before we finally found the CA216 pod," the team wrote in a caption alongside footage of the white calf. Whale-watchers enjoyed a lengthy stay with the orcas as the pod made their way up the coast, sometimes approaching boats for a closer look.

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Affectionately known as "Frosty", the pale-coloured calf was born in 2019 and owes its unusual hue to a rare genetic condition. Aside from Frosty's head and dorsal fin, the bulk of the youngster's body is a white-grey colour. 

“There are multiple reasons such patterns occur but genetics is a large factor,” Luke Rendell, a biology lecturer at the University of St Andrews’ sea mammal research unit, told Newsweek. In Frosty's case, the white colouration is caused by a condition called leucism, which results in a partial lack of pigment in the skin. This differs from albinism in which animals appear entirely white and usually have a red or pinkish eye.

The condition is rare in orcas and may come with some complications. In the 1970s a white orca, later nicknamed Chimo, was found in British Columbia. Sadly, she died at a young age as a result of a disease called Chédiak-Higashi syndrome which affects skin colouration, but can also have an impact on the immune system.

For now though, Frosty seems to be doing well and has healthy family members for support. According to Mark Girardeau from Whale and Dolphin Conservation this particular pod has been spotted as far south as Mexico and as far north as Canada.

Top header image: timnutt, Flickr 

The rarely seen event took place on 2 January just a few miles off the coast of Dana Point in Orange County, according to the team at Capt. Dave's Dana Point Dolphin & Whale Watching Safari who uploaded the footage to their YouTube channel. The tour group initially spotted a gray whale estimated to be around 40 and 50 feet (12 to 15 metres) in length, which they suspected was one of many that migrate along a back-and-forth route between their Mexican breeding grounds and the cold, nutrient-rich waters of the Arctic.

As they approached, the whale began acting sporadically, and the tour operators noticed a small pool of blood on the surface of the water near the massive mammal. Worried onlookers feared the whale was under attack from a shark, but were pleasantly surprised when a tiny calf emerged to take its first breath.

"After surfacing, the newborn calf began learning how to swim and bonding with its mother," the team explained in the video description. "The female even brought the calf over to the boats as if to show off her offspring and say hello."

The mama whale swam alongside her calf, gently nudging the newborn to the surface and positioning herself underneath the youngster allowing it to rest near her face. Gray whales are born with soft tails (or flukes) which can take a day to stiffen up, marine biologist Alisa Schulman-Janiger told NPR. "The mom is holding the calf up, supporting it so the calf can rest and [is] actually helping it be able to take a breath," she explained. 

These intimate moments of contact also help strengthen the bond between mother and calf, something that land mammals would usually do by smelling one another. 

Gray whales typically give birth in protected lagoon waters in Baja California, Mexico, where predators like orcas are less likely to target the calves and the youngsters that are yet to build up their blubber are not threatened by frigid water temperatures. However, "there are times when calves just won't wait and are born during the migration," the team from Capt. Dave's Dana Point Dolphin & Whale Watching Safari explain.

This mother was likely on her way south to Baja California having already traveled thousands of kilometres from her feeding grounds in the Bering and Chukchi Seas near Alaska. This annual migration along the U.S. west coast is one of the longest undertaken by any mammal species. 

It's hoped that the youngster will survive in the dangerous open waters, especially considering gray whale population numbers in the North Pacific are on the decline. In 2022, populations were estimated at 16,650, down from 27,000 just 6 years prior. Strandings caused by an unusual mortality event are at least partly to blame for the decline.

Top image: Merrill Gosho/Wikimedia Commons

It was the most unexpected finding from a recent study which captured the first video and sound of bottlenose dolphins feeding on live fish. Footage from the study shows that the mammals appear to suck down their prey by expanding their throats and flaring their lips rather than simply charging at the fish (or snakes) as previously thought. The research also sheds light on the chorus of squeals, clicks and buzzes produced by the animals during and after hunting.

"They clicked almost constantly at intervals of 20 to 50 milliseconds," Dianna Samuelson Dibble, a researcher at San Diego's National Marine Mammal Foundation (NMMF) and a member of the study team told The Guardian. "On approaching prey, click intervals shortened into a terminal buzz and then a squeal. On contact with fish, buzzing and squealing was almost constant until after the fish was swallowed."

The six dolphins used for the research are highly skilled mine-detectors deployed and trained by the US Navy to make the ocean safer for naval ships and other vessels. The animals swim in the open ocean every day and their ability to locate, communicate, and mark mines on the seafloor is incredibly accurate and effective (although some animal activists challenge the ethics of using dolphins for service – this deep dive from Hakai Magazine is worth a read if you're looking for more context). The researchers believe that the captive animals are the perfect candidates for a study focused on gleaning insights into the underwater hunting and eating behaviour of these much-loved sea mammals.

"These findings are an incredible addition to the literature providing detailed analyses during prey capture in the open ocean, which would be very difficult to achieve with wild dolphins," Dr Brittany Jones, a scientist at NMMF, told The Guardian.

The mesmerizing GoPro footage offers a close-up glimpse of dolphins hunting and eating live fish, all the while making a series of clicking and squealing sounds. The most fascinating capture is that of dolphins consuming yellow-bellied sea snakes, a behaviour that came as a surprise to the research team. Dolphins had previously been observed chasing after sea snakes but never actually eating them. Yellow-bellied sea snakes are venomous and can be dangerous if the venom is absorbed through bites or open wounds.

Despite the potential risk, one dolphin was observed slurping up eight snakes. Scientists reported to The Guardian, "The dolphin clicked as it approached the snake and then sucked it in with a bit more head jerking as the flopping snake tail disappeared and the dolphin made a long squeal." The slithering snacks didn’t appear to have any effect on the dolphin but it's unclear if sea snakes form a regular part of the diet of wild dolphins. The fact that the Navy dolphins have been raised in captivity needs to be taken into account while pondering the dolphin’s choice in food, the researchers explained.

Illustrated perfectly in a clip recently released by Michael McCarthy, owner of See Through Canoe, “fish-whacking” or “fish-kicking” is all about timing and accuracy. A dolphin will glide towards a school of fish (mullet in this case, according to McCarthy), dispersing the shoal and creating general panic and confusion. As the fish move to regroup for safety, the dolphin waits for the perfect moment then pivots in a fluid sweep, whipping its tail through the water and batting one of the straggling fish high into the air. Stunned and possibly injured from the blow, the fish is subdued for long enough for the dolphin to scoot over and scoop up its prize.

This is not the first time that McCarthy has filmed the remarkable behaviour. Speaking to National Geographic back in 2019 regarding similar aerial footage, the amateur videographer points out that it’s the most common feeding technique he’s observed among the bottlenose dolphins near his home in Seminole, Florida.

It’s a tactic that has been documented in a number of dolphin species in an array of areas from the US Gulf Coast to New Zealand, Stefanie Gazda, a biologist at the University of Florida explained to National Geographic.

Dolphins have a diverse arsenal of hunting techniques and tricks at their disposal. “Fish-whacking” is just one method that has arisen independently in different dolphin populations across the globe. It seems that a few key individuals practise the fish-flinging behaviour while others may opt for a different approach, explains Shannon Gowans, a behavioral ecologist at Eckerd College in St. Petersburg who has witnessed the fish-whacking technique before. “One dolphin does this, another does that ... This helps reduce competition between individuals, and gives the [fish-punters] an advantage over those doing the same thing as everybody else.”

Although the tail-slapping technique really only benefits a single dolphin, these accomplished hunters are more commonly known to team up when looking for food. Some dolphins populations – like those that take advantage of the feast provided by South Africa’s annual Sardine Run – often work together to corral their prey into smaller shoals or “bait balls”. Once the fish are gathered in a tight cluster, the dolphins take turns plowing through the shoal, picking them off one by one.

“Bait balling” is a technique favoured by dolphins living in the open ocean, but those that prefer to hang out in estuaries and river mouths may develop a different approach. Instead of charging into a school of fish, these shallow-water hunters have been recorded driving them towards the shore, pushing them onto river banks and gobbling up as many as possible before slipping back into the water.

Other groups of dolphins living in shallow water prefer to use mud to snag their meals. Working as a group or on their own, some dolphins in Florida have been documented circling schools of fish, dragging their tails along the sea floor as they go to create a murky whirlpool of churned up sediment. The fish become disorientated in the low visibility and in their attempts to flee the muddy water they inadvertently swim straight into the mouths of dolphins.

Diverse are the techniques of these masterful hunters and there is likely still much we do not know.

Top header image: jumping lab/Flickr

That evocative line comes from an account last month posted by Kristy Brown of Naturaliste Charters, describing a dramatic take-down of a good-sized blue whale – the largest animal on Earth – by a big group of orcas off the southern coast of Western Australia (Watch the video here).

The attack occurred over the Bremer Canyon system, a network of submarine trenches striking the continental shelf break about 70 kilometres southeast of the town of Bremer Bay. Such “shelf-incising canyons” are often associated with significant marine productivity, and the Bremer system is no exception: It’s well known for major congregations of cetaceans, from bottlenose and common dolphins to sperm whales and, yes, orcas, well more than 100 of which gather here during the austral summer and fall – the largest-known seasonal orca get-together in Australian waters.

According to Brown’s report, the Naturaliste Charters whale-watching vessel came across orcas on the morning of March 16. “The action started slow, we were seeing a couple of surges around, but it didn’t seem uniform,” she wrote. “Usually surging orcas are spread wide moving loosely in one direction when they hunt a beaked whale. But this was different, these surges were scattered.”

Eventually they realised the orcas were working a blue whale reckoned at about 16 metres long: either a juvenile blue, Brown told Live Science, or a full-grown pygmy blue whale, a subspecies. (Blue whales, particularly those of Antarctic populations, may grow to 30 metres and weigh 160 tons or more.)

More and more orcas arrived on the scene, including “at least six big males from different pods.” Ultimately, the observers estimated that anywhere between 50 and 70 killer whales were taking part. “They were literally everywhere, and they were working together,” Brown wrote. “They were driving this whale from the depths of the S bends within the Bremer Canyon system at 1,000m of water and gradually forcing it onto the shallower continental shelf. This was their strategy, and they all seemed to know it.”

The orcas relentlessly attacked the blue’s jaw, a common strategy when the predators hunt large whales. Orcas are known to prize the tongues and lips of baleen whales, and furthermore attacks aimed at the victim’s head may reduce the danger of being whacked by its potentially dangerous flukes.

The attack unfurled for hours before the blue finally gave out in the afternoon. “A bubble of blood rose to the surface like a bursting red balloon,” Brown noted. The orcas wasted no time feasting: “We saw some blubber, only one hunk of flesh, and it was gone.”

The kill site attracted not only seabirds but also a hammerhead shark and long-finned pilot whales, also known to frequent the Bremer submarine canyons in large numbers.

There are relatively few recorded cases of orca predation on blue whales, especially when compared with other baleen whales more frequently recorded falling on the killer whale’s menu. An admittedly outdated (1991) review of orca interactions with other marine mammals noted four cases of killer whales preying on blues, including a pre-1925 report of five orcas killing an adult blue whale in Antarctica, as well as a handful of observations of the two species mingling apparently peacefully. More common cetacean prey for orcas, according to that survey, included fin, minke, and humpback whales – among the blue whale’s relatives in the rorqual family – as well as grey and bowhead whales, narwhals, and Dall’s porpoises.

Nonetheless, humans have witnessed some notable cases of orcas preying on or harassing blues in recent decades. In 2003, killer whales were seen feeding on a blue-whale calf within the Costa Rica Dome, an upwelling area about 230 kilometres west of Nicaragua. In 2017, some feisty orcas in California’s Monterey Bay charged an adult blue, which rapidly escaped.

Even if the Bremer Canyon blue whale was a juvenile of the larger subspecies, it was still much bigger than the orcas that dined on it. This – and the sheer number of killer whales involved – makes the incident noteworthy, but it’s actually the most recent of several recent attacks on similarly sized blues in this orca hotspot. In March 2019, orcas killed a 20-metre-long pygmy blue whale here – during a thunderstorm, no less – with upwards of 50 killer whales digging into the carcass. A mere two weeks later, a 15-metre pygmy blue also fell to orcas.

As Ian Dickinson reported here at Earth Touch on those incidents, some experts believe attacks such as the two 2019 ones and last month’s could be more frequent than previously appreciated. “Given the slow but steady increase in the Southeast Indian Ocean pygmy blue whale population (approximately 2,000 whales) . . . there is a possibility the killer whales of the Bremer Canyon are taking advantage of this population,” Micheline Jenner of the Centre for Whale Research told Dickinson.

And John Totterdell of CETREC WA (Cetacean Research), who witnessed the first of those 2019 attacks, posted on Facebook: “Even though this is the first recorded encounter (off Australia) of a large baleen whale succumbing to an attack, it’s likely other large whales (including blues) often face the risk of predation from killer whales.”

It’s worth noting, too, that an older observation of an orca attack on a blue whale – a well-photographed instance off Cabo San Lucas in Baja California in the late 1970s – involved an 18-metre juvenile blue, harried by close to 40 orcas.

Just how frequently orcas actually kill full-grown baleen whales – also known as mysticetes or “whalebone” whales – remains a matter of some debate. A 2007 paper suggested that, in high-latitude areas, adult mysticetes bearing orca bite scars (rake marks) usually have them when they’re first identified by researchers, and rarely seem to acquire new ones, suggesting they’d likely received them as younger animals. (The minke whale, a relatively small rorqual that doesn’t max out much longer than an orca, is an exception: Killer whales often hunt adults of this species.)

Calves of large whales may be especially vulnerable to orcas when migrating from their nursery waters at low latitudes to high-latitude feeding grounds. The mammal-eating killer whales of the North Pacific known as Bigg’s (or “transient”) orcas, for example, frequently target grey-whale calves journeying with their mothers northward along the western coast of North America (the aforementioned Monterey Bay is a common site for such predation). Orcas also frequently prey on humpback calves migrating along the coast of Western Australia.

Mother grey and humpback whales will both vigorously defend their calves from orcas; in the case of humpbacks, other adult whales will do so as well. Indeed, humpbacks are known for seemingly coming to the aid of even other animals under assault by killer whales on occasion – a possible case of interspecies altruism. 

Top header image: jellybeanz/Flickr

The Farallon Islands, off the coast of San Francisco, are one of the world’s great biodiversity hotspots. While scientists regularly visit the area to study sharks or birds, the current focus has been on the 47 blue whales recently documented around the Farallones. The blue whale (Balaenoptera musculus) belongs to the baleen whale suborder Mysticeti and is the largest animal on the planet. Weighing as much as 200 tons (181 metric tonnes), they can reach up to about 110 feet (34 metres) in length and their mottled blue-grey colour can be used to identify individuals. The giant animals are listed as endangered under the Endangered Species Act.

The recently sighted blue whales not only left visible "footprints" — smooth patches on the ocean’s surface formed when whales dive and push water up with their flukes — but they also announced their presence with spray from their blowholes. Blue whales feed almost exclusively on krill, straining huge volumes of water through their baleen plates to sieve out up to six tons of the shrimp-like crustaceans in a single day. Krill are found in all the world’s oceans and make up an important component of many ecosystems. The name comes from the Norwegian word krill, meaning "small fry of fish" also known as "whale food," since they form a large portion of many whales’ diets. 

"It’s extraordinary. It may be an absolute record," NOAA Greater Farallones spokeswoman, Mary Jane Schramm told Marine Industry News. "Essentially, the driver here is krill and that’s the food they [the whales] feed upon this time of year, and we have it in such great abundance in the marine sanctuary that the blue whales have apparently targeted our water specifically to feed."

But their need to feed may be putting them in harm’s way. "Their enormous size dictates that they maximise feeding effort when food is available, and this sometimes takes them into dangerous waters," explains Maria Brown, superintendent of the Greater Farallones National Marine Sanctuary in a press statement. "While focused on feeding, they are not likely to recognise or evade a ship’s approach."

The biggest threats currently facing blue whales are vessel strikes and getting entangled in fishing gear. Due to this, many officials and conservationists have called for large ships to slow down while sailing near the whales' feeding grounds. The Coast Guard along with the National Oceanic and Atmospheric Administration (NOAA) – the organisation that manages the marine sanctuary that surrounds the Farallones – have requested that large vessels slow down to 10 knots when sailing through the area. "The sanctuaries are working with the U.S. Coast Guard to notify mariners to be on the lookout for the whales and maintain slow speed and maximum possible distance to avoid deadly collisions," says Brown.

The blue whales have been around for a few days, with scientists on the island counting 23 of the animals in the area a few days before the number jumped up to 47. Nobody can predict how long this group of blue whales will stay in the area for, but here’s hoping they take advantage of the aquatic smorgasbord and quieter waters as a result of COVID-19.

Top header image: Michael Bamford, Flickr

The explosion launched several slabs of meat and blubber into the air, sending reporters and spectators scurrying for cover. Remains of the 45-foot (14-metre) sperm whale were scattered up to 800 feet (240 m) away. "The blast blasted blubber beyond all believable bounds,” quipped one local news reporter at the time. The event is undoubtedly the most fabled whale detonation on record (yes, there have been others).

Now, fifty years later, this grisly snippet of Oregon history has been commemorated with a newly-named park. On June 13, the City of Florence hosted a low-key dedication ceremony to unveil the new sign for "Exploding Whale Memorial Park" situated on the sandy shores of the Siuslaw River. The park was set for a grand opening in May at the 113th annual Florence Rhododendron Festival to tie in with the event’s special theme: "Blast from the Past". But the festival was cancelled in the wake of COVID-19.

According to a statement from the City of Florence, potential names for the park were proposed by community members and the winner was selected in a "Name the Park" survey. While many of the suggestions like "Rolling Tides Community Park" or "Dune View Park" highlighted the area’s natural beauty, voters couldn’t resist the quirkiness of cetacean detonation – "Exploding Whale Memorial Park" won in a landslide.

The Oregon dynamiting may be the most famous on the books, but its not the only time a whale carcass has been affixed with explosives and "redistributed" to rest in pieces. In some areas like South Africa, Iceland, and Australia, it’s not uncommon for officials to drag problematic whale carcasses out to sea where they are sunk by means of explosives. Government-sanctioned, controlled detonations have even been used to euthanise animals that could not be saved.

Take away the dynamite-happy humans and some expired whales will blow up all on their own. When the remains of a beached whale decompose, gases like methane build up inside the carcass – if the resulting pressure is powerful enough, the carcass may burst. As this biologist in the Faroe Islands discovered when degassing one in 2013:

Nine years before that, Tainan City in Taiwan joined the annals of whale blast history when a decomposing sperm whale burst while being transported on the back of a truck en route to a university lab for preservation. The explosion splattered store fronts and spectators with blood and entrails.

So how should we dispose of decomposing whales, then? Despite the insistence of the engineer in charge of the notorious 1970 blast that everything went to plan and the whole thing was, er, blown out of proportion by the media, explosions seem an ill-advised strategy – at least in the case of sizeable whales that are stranded near car parks or other areas where "blubber rain" may cause extensive damage. When a whale washed up on Oregon's North Coast in April this year, the authorities chose the least dramatic solution and buried the 40-foot creature (much to the chagrin of one local reporter who asked: "Do you really want to live in a state that won't dynamite giant animal carcasses when given the chance?"

Clearly we have learned a lot about whale disposal in the decades since that gory November day in Florence. Where possible, carcasses should be dragged out to sea and sunk so the remains may become a smorgasbord of blubbery delight for underwater species skilled at dismantling large-carcasses. If the whale holds some scientific value (and can be transported to a lab without decorating shopfronts with viscera), then preservation may also be a good way to go.

Lest we end our exploration of exploding whales without providing you with some useful info, if you come across any stranded marine mammals, here are the right steps to take.

Top header image: Tim Ellis, Flickr

The orcas were initially spotted cruising up the coast towards Orange County, but things heated up when they narrowed in on a pod of common dolphins. "It was surprising to me with what persistence they chased this dolphin pod,” Newport Coastal Adventure owner Ryan Lawler told The Mercury News. "They chased it for two miles at a constant pace – like wolves chasing down their prey, trying to tire their prey out."

Killer whales are among the world's fastest-moving marine mammals, capable of clocking speeds over 30 miles (48 kilometres) per hour (an impressive feat when you consider that they can weigh up to 11 tons!). The black-and-white predators are armed with a mouth full of large, interlocking teeth and are highly intelligent and social – which makes them particularly efficient killers.

Hunting tactics are typically defined by what's on the menu: schools of fish are snared in a net of bubbles from below, while sharks are likely rammed and then their bodies torn open just below the pectoral fin so the orcas can hoover up their nutrient-rich livers. But when it comes to nippy and agile common dolphins, the hunt often sees killer whales teaming up in a coordinated attack and pursuing their quarry at high speed.

"They went after that [dolphin] baby. I guess that was an easier target," Larmand recalls. "They’d come from different directions, they were corralling it and getting it to go in the direction they wanted it to go. They knew exactly what they were doing and how to do it. It was crazy to watch."

Whale-watching guides and marine researchers identified the orcas as belonging to a group usually found in the Eastern Tropical Pacific (ETP) and – according to Alisa Schulman-Janiger, co-founder of the California Killer Whale Project – it's unusual to encounter them at this time of the year. ETPs usually hang out in waters off Mexico or Costa Rica and turn up occasionally in California from November through January when the water is a bit warmer, she explains.

Schulman-Janiger will be analysing photos in an attempt to identify the individuals, but she suspects that this group is not the same one that turned up in town late last year. Not much is known about ETP orcas, but marine mammals do seem to make up, at least, part of their diet. 

Top header image: timnutt, Flickr

Japan recently left the International Whaling Commission (IWC) and has now caught the first whale in its waters since resuming commercial whaling, 33 years after a global ban came into effect. As a non-member, Japan is no longer bound by the International Convention for the Regulation of Whaling (ICRW) – the rules that the IWC has used to manage whaling since 1946.

The IWC’s moratorium on commercial whaling has broadly been a success – whale populations have increased where whaling was the primary threat. The humpback whale is one example of successful recovery, but species such as the northern right whale have never recovered from centuries of whaling and are in critically low numbers.

Outrage and despair greeted Japan’s decision to relaunch commercial whaling in its waters, although the conservation status of many species may be unaffected. Still, Japan’s exit from the IWC is a worrying message to the international community at a time when collaboration on environmental issues is sorely needed.

Why has Japan left the IWC?

Japan introduced a proposal at the IWC in 2018 which would allow it to restart commercial whaling. This was voted down – the proposal that was approved in its place supported a shift in the commission’s goal towards banning all commercial whaling in perpetuity.

A permanent commercial whaling ban might sound like an ordinary step, but the IWC’s purpose since 1946 has been “the orderly development of the whaling industry”. The IWC has gradually pivoted to focus more on conservation and other threats to whales since then, but one of its founding goals was to support the whaling industry and the people it employed. As the whaling industry has declined and attitudes towards whales have changed around the world, the IWC has changed too. Japan meanwhile has always been clear it wants to resume commercial whaling and is leaving the IWC because the moratorium was only meant to be temporary and lifted when whale populations could support whaling.

Japan isn’t the first country to leave the IWC because of frustration with its rules on commercial whaling. Iceland left in 1992 and rejoined in 2002 as a full member but with a reservation to the moratorium that allows it to commercially whale. Norway objected to the moratorium decision in 1982 and so kept its right to commercially whale while remaining a full IWC member.

A mixed outcome for whales

For most whale species, the exit of Japan from the convention banning commercial whaling will have few consequences. Whale populations in the Southern Ocean are even likely to benefit as Japan will lose its special research permit for scientific whaling in the region by leaving the IWC. Japan mostly took Antarctic minke whales (Balaenoptera bonaerensis) here, but this species is not considered endangered.

It’s a different story for whales found within Japan’s Exclusive Economic Zone (EEZ). No longer bound by the IWC’s rules, Japan can harvest whales here under the right given by the UN Convention on the Law of the Sea but the number and species it will decide to take hasn’t been announced. One vulnerable population living in Japan’s EEZ which may be affected are common minke whales (Balaenoptera acutorostrata), which are genetically distinct and possibly number fewer than 5,500. It’s worrying this population hasn’t shown the same robust recovery seen among other minke whales.

Japan will want to prove to the world it can whale sustainably but the long-term future of whaling is uncertain. The market for whale meat in Japan peaked after World War II and is now a shadow of its former self. Although still eaten in cultural ceremonies and a few localities in northern Honshu, consumption is around 40g per capita each year - about the size of a slice of ham. Whether Japan’s diminished appetite for whale meat will reduce its whaling efforts though remains to be seen.

A way forward?

Research by the IWC scientific committee has greatly advanced our understanding of whale ecology and how to address other threats to their survival, like pollution, bycatch and climate change. Japan’s exit from the IWC doesn’t threaten the organisation’s activities and every effort should be made to continue this important research. But if the “International Whaling Commission” is to become a conservation organisation, then maybe its status as a whaling commission is outdated.

Countries could continue to work together on whale conservation by using the Convention on Migratory Species. This specifically targets the conservation of migratory species and their habitats, and would apply to protecting whales. In fact, there is already a regional agreement between countries that’s focused on whale conservation.

Agreements made under this convention might be better able to deal with the diverse threats facing whales. A whale research programme focused on conservation – as opposed to a whaling research programme – made up of the IWC scientific committee and Japan might have fewer conflicts as their objective would be clearer.

Japan’s exit from the IWC is a complicated issue beyond just whale conservation – it highlights the need for the international community to overcome disagreements. Asking why the IWC has succeeded and failed at different times can help us improve the way we work together on global challenges as after all, whaling is only one example of the many urgent and complex environmental issues that demand a global response. How well we work together determines more than just the fate of the world’s whales.

Sui Phang, Research Fellow in Blue Governance, University of Portsmouth and Peter Bridgewater, Adjunct Professor, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Norwegian fishermen were reportedly approached recently by a beluga whale wearing a Russian harness, complete with GoPro camera holder, sparking speculation that the animal had been trained to gather intelligence by the Russian Navy. While this theory has not been confirmed, it is entirely plausible: armed forces around the world have a long and disturbing history of exploiting marine mammals.

Russians Likely Used This Beluga Whale As a Spy. Here's Why. https://t.co/0ccsUF7yTq pic.twitter.com/Sl2dAknVuw

— Live Science (@LiveScience) April 30, 2019

In the late 19th century, European militaries had come to appreciate that thoroughly-trained and well-handled dogs could perform useful military services, such as finding wounded soldiers on the battlefield and guarding military installations and outposts. Over the course of the 20th century, new roles were found for them: notably, detecting mines and explosives during World War II.

Given the success achieved with dogs, it was perhaps inevitable that experiments would begin with other intelligent and trainable animals, including marine mammals. The earliest of these experiments took place during World War I, when Britain’s Royal Navy unsuccessfully attempted to train sea lions to locate German submarines.

The early training – conducted at a facility on Lake Bala in Gwynedd, Wales – went well. But once the sea lions were released into the open sea, they were generally found to be more interested in pursuing shoals of fish than U-boats – much to the frustration of the officers involved.

Navy dolphins

These efforts were revived by the United States and other nations during the Cold War, following the discovery that dolphins use echolocation to navigate underwater, emitting high frequency “clicking” sounds and listening for the echos that bounce back off their surroundings to locate and identify nearby objects.

A number of species of marine mammals, including dolphins, porpoises, sea lions, orcas, belugas and pilot whales, drew the attention of rival militaries. Not only do these animals possess extraordinary sensory and physical abilities, they can also change their behaviour – traits which meant they could be trained to perform much the same tasks at sea that dogs performed on land.

In coldly scientific language – and with little acknowledgement of the sophisticated intelligence and capacity for emotion expressed by these animals – one American manufacturer of military sonar equipment described them as:

"Self-propelled marine vehicle[s], or platform[s]; with a built-in sonar sensor system suitable for detecting and classifying targets; and carrying an on-board computer … capable of being programmed for complex performance."

The US Navy began its marine mammal programme in 1960, originally hoping to both improve the hydrodynamics of its torpedoes, and its ability to detect objects under water, by studying dolphins. Yet the scope of this programme appeared to expand rapidly. Dolphins were soon being trained to locate enemy mines and lost objects on the seabed.

According to American journalist David Morrison, a team of dolphins was also deployed to South Vietnam to guard the US fleet anchored in Cam Ranh Bay against saboteurs in 1971. He also asserted that navy dolphins were transported to the Persian Gulf in 1987 to detect Iranian mines, and guard against enemy frogmen attempting to attack the US Navy’s floating command post.

Protests for porpoises

The use of these animals for military purposes has caused much controversy over the years. One of the more disturbing questions concerns what exactly these dolphins have been trained to do, should they encounter enemy saboteurs. In 1976, Michael Greenwood – a veteran of the Navy dolphin project – claimed that dolphins assigned to the “swimmer nullification program” were equipped with syringes filled with carbon dioxide to kill intruders.

Despite vehement denials from the US Navy, such allegations have frequently resurfaced. Soviet Russia reportedly trained dolphins in a similar manner at a facility in Crimea on the Black Sea. In 2000, the BBC reported that many of these dolphins were sold to Iran, following the collapse of the Soviet Union. The facility was re-opened by the Ukrainian Navy in 2012, but since the Russian annexation in 2014 has been back in the hands of the Russian Navy (although Ukrainian sources claim that the dolphins have since starved, having refused to accept food from Russian handlers).

The treatment of these animals has been another matter of long-standing concern. David Morrison reported allegations of systematic mistreatment and poor standards of care for animals in the American programme, noting that it had become the focus of animal rights activism. According to one report in May 1987, “someone billing himself only as ‘Charly Tuna of RainBoWarriors’, cut the nets around four of the San Diego dolphin enclosures”.

Certainly, a great deal of the secrecy continues to surround the military use of sea mammals. And as Morrison observed as far back as 1989, this reflects “the fear of exciting public opposition to its efforts, opposition sparked by the great affinity that so many humans feel for these engaging creatures”.

More recently, animal rights organisation People for the Ethical Treatment of Animals (PETA) has protested the US deployment of dolphins to the Persian Gulf, stating:

"It is not ethical to put animals in harm’s way … War is a human endeavor, and while people and political parties may decide war is necessary, animals cannot."

Whatever the exact origin of the (apparently friendly) beluga whale discovered in Norwegian waters, the story serves as a reminder that marine mammals are still commonly exploited for military purposes in the modern world. Their replacement by robotic submersibles seems, at the moment, a regrettably distant prospect.

Gervase Phillips, Principal Lecturer in History, Manchester Metropolitan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Top header image: Jason Pier, Flickr
Main image: Sheila Sund

With the death of the young female orca calf known as J50 in the Pacific Northwest in September 2018, the population of southern resident killer whales has fallen to 74.

At the time, Ken Balcomb, the founder of the Center for Whale Research in Friday Harbor, Wash., said the world was “witnessing a slow motion extinction” of this population of killer whales.

These incredibly low numbers paint an alarming picture for the future of the endangered southern resident killer whales. Experts predict that two more southern resident killer whales will die by this summer due to starvation. Only 40 of the calves born to the southern resident killer whale population have survived since 1998, and 73 have gone missing or found dead. No newborn whales have survived since 2015.

Why are they in such dire straits? The three main stressors for this dwindling population are noise pollution from increased vessel traffic, ocean contaminants and declines in Chinook salmon — the whales’ main source of food.

Research shows that a quieter ocean may help save the southern resident killer whale population, but without regulations yet in place, it may be too little, too late.

Impacts of ship noise

Three groups of orcas — the transient, offshore and resident — live along the Pacific coast. The resident group is further classified into northern and southern populations that have some distribution overlap but do not interbreed. The southern resident population, typically found from southwestern Alaska to central California, is the only orca population in Canada listed as “endangered.”

Underwater ocean ambient noise has increased by approximately 15 decibels in the past 50 years due to increased marine transportation and other anthropogenic (human-made) sources.

Noise travels approximately five times faster in water than air and has a wide range of detrimental effects on whales. With increasing numbers of vessels plying the world’s oceans, their engine noise is making it hard for many whale species to communicate.

The documentary “Sonic Sea” likens anthropogenic ambient noise, such as that from vessel engines and drilling for oil or gas, to being trapped in a loud, dark nightclub, unable to see or hear the people right next you. While a human can leave a noisy night club, whales cannot escape these underwater noises.

According to a recent study, the frequency of ship noise overlaps with that of orca communication. It masks noises the orcas make and can interfere with echolocation, which orcas use for navigation and to hunt prey. For the southern resident killer whale population, the limited availability of Chinook salmon combined with vessel noise adds to the challenge of finding food.

The Haro Strait, off the coast of Victoria, is the summer feeding habitat of the southern resident killer whale population. It is also one of the loudest areas along the Pacific coast, especially in the frequency range that orcas use for communication. As noise from vessels has increased in loudness and now covers a larger geographic area, killer whales have adjusted their vocal communication by increasing the amplitude of their calls to compensate for the underwater noise. But this increased vocal output could have energy costs, cause increased stress or further hinder communication.

Mitigating ship noise

Unlike other forms of marine contamination, noise levels in the ocean can be reduced with relatively small interventions. A recent study investigated ways to reduce vessel noise, and suggested adopting a “multi-pronged approach” to mitigate ocean noise.

The study found that when fast-moving, large vessels reduced their speed to 11.8 knots, the emitted noise dropped by three decibels. This reduction is consistent with precautionary “Okeanos” targets supported by the International Maritime Organization to reduce shipping ocean noise by three decibels within a decade. Shipbuilding industries are already retrofitting noisy ships with quieter engines and designing even quieter ones.

Scientists studying the Haro Strait have suggested using a convoy approach to manage the increasing amounts of ship traffic. Incoming ships would be grouped based on their time of arrival and enter the strait together. Ship noise may increase during the convoy period, but its duration is dramatically reduced. The same study suggested designating B.C.‘s Salish Sea as a Marine Protected Area (MPA) during the summer months to help the southern resident killer whale population recover.

Both Fisheries and Oceans Canada (DFO) and the U.S. National Oceanic and Atmospheric Administration (NOAA) have implemented regulations to mitigate the stress on the orca population. DFO is working with U.S. agencies to coordinate measures to reduce underwater noise impacts on the southern resident killer whales.

In 2017, DFO published an action plan to aid in the recovery of the southern resident killer whales, including reduction of underwater noise, limiting disturbance from humans, monitoring whales from a safe distance, ensuring accessible food supply and protecting critical habitat. Recovery plans are legally required for endangered species listed under the Species at Risk Act (SARA), but have been criticized by conservationists for delays in implementation.

In 2018, the government of Canada imposed restrictions on Chinook salmon harvesting with the hope of increasing their availability for the southern resident killer whales.

Washington state Gov. Jay Inslee also launched a task force to create a long-term plan for the recovery and future sustainability of the southern resident killer whales. The recommendations ranged from increasing Chinook salmon availability to a temporary whale-watching moratorium, but they remain a long way from being implemented.

Glimmers of hope

Whale-watching boats and commercial ships are facing an increased number of regulations on how close they can get to orcas in the Salish Sea. As of July 2018, vessels must stay 200 metres away to help limit disturbance of the whales. And in August, Canada’s Federal Court of Appeal rejected the proposed Trans Mountain pipeline expansion, which could result in a seven-fold increase in tanker traffic in the Salish Sea, to 35 vessels a month.

While addressing noise reductions alone is unlikely to be sufficient, it is a necessary first step. The delay in implementation of measures combined with the uncertainty of the effectiveness of implemented measures can make the prospects seem grim for this declining orca population.

However, it is important not to lose hope. There have been recent reports that three females in the southern resident killer whale population are pregnant.

With increased awareness, further action and a $167.4 million investment towards the protection and recovery of endangered whales by the federal government, maybe it’s not too late to save the southern resident killer whales.

Priyanka Varkey, Master's student, Dalhousie University and Tony Robert Walker, Assistant Professor, Dalhousie University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Top header image: Shutterstock

"I love how in this instance nature came to the human. Not the other way around," Porter told the Daily Mail. The calf – curious about the unusual creatures bobbing nearby – left its mom's side, flipped upside down and popped up directly beneath one of the snorkellers, briefly engaging in a moment of humpback-human mutual belly rubbing, before gently moving off. 

"I'm sure the mum knew the humans were close by but she had enough trust for her baby to interact with the humans, despite possibly only being a few weeks old," Porter stated.

Humpback sightings are fairly common around French Polynesia at this time of year as the behemoths migrate north from Antarctica to the warmer waters of the Pacific to give birth and raise their young. As a result, the area is home to a thriving ecotourism industry that is largely centred on whale-swimming tours. Interaction rules and regulations limit the number of tourists allowed in the water and ensure that there is minimal impact or stress on the animals.*

While it's unclear if these swimmers were part of an official tour group, the adult humpback certainly seems comfortable sharing the water with a pair of flipper-clad humans. "She appears to be extremely calm, and thus may be habituated to the presence of people," suggests Dr Joy Reidenberg, a comparative anatomist specialising in cetaceans, adding that the calf's playful antics conjure up images of a "child purposefully stomping in rain puddles".

Pregnant humpback whales prefer shallow waters to give birth, where it’s thought that they shelter from predators and possible attacks dished out by males. Calves stick close to their mothers on whom they depend for protection and food. Curiosity clearly got the better of this youngster and thankfully the encounter was a peaceful one.

*According to a representative of the French Polynesian government, these snorkellers were, in fact, breaking whale-watching regulations. The rules outline that swimmers should remain at least 30 metres away from whales in the water, and if they are approached by the behemoths, contact should be avoided. Visitors to French Polynesia are urged to select reputable tour operators and always adhere to interaction regulations.

More than half of the world’s killer whales are threatened by a group of toxic industrial chemicals that accumulate in their blubber and can be passed on from mother to calf. That’s according to a new study led by scientists in Denmark and published in the journal Science. Killer whale populations found in the most polluted seas around Japan, Brazil, the UK or in the northeast Pacific, the authors report, are “tending toward complete collapse”.

Polychlorinated biphenyls (PCBs) are a ghost from the past. These chemicals were produced in immense quantities from the 1930s onwards and were broadly phased out in the 1970s/1980s as environmental concerns grew.

As they were very stable and were unable to conduct an electrical current (and therefore excellent insulators), they were mainly used in the electrical supply industry. These same properties also saw them being used in a whole array of miscellaneous applications including as sealants and additives in construction.

It is this chemical stability that means PCBs stubbornly refuse to degrade in the environment and I have spent the past 25 years studying how these and other contaminants end up accumulating in the Arctic, for instance. However, there are two other properties that make these particular chemicals uniquely problematic, unlike, say, common air pollutants or most heavy metals.

The first is that PCBs are semi-volatile, which means that over time they can evaporate into the atmosphere but then later deposit on surfaces when encountering cooler temperatures or with rainfall or attached to particles. Over decades this continued evaporation and deposition (termed “cycling”) has ensured that they’re smeared around the entire planet. PCBs are just as likely to be found deep in the ocean or in Arctic snow as they are in neighbourhood soils, although the concentrations in soil close to “primary sources” such as cities may be orders of magnitude higher.

The second problem is that PCBs tend to work their way up the food web, accumulating in ever higher concentrations as tiny animals (and their unwanted chemicals) are eaten by small animals, who are eaten by larger animals (who take on those same chemicals), and so on. This process of “biomagnification” is most evident in marine food webs where fatty tissue like blubber (a home for PCBs) is an important feature of animals at the top of the food web such as killer whales.

New diets mean new exposure

So, if the chemicals were largely phased out in the early 1980s, why are they continuing to cause a problem? It’s true that background concentrations have declined over the past 20 years or so, based on measurements of PCBs in the air in animals such as seabirds and even in human breastmilk. But the trend varies from place to place and between different species, and there is evidence that climate change is disturbing the “cycling” of these chemicals, potentially slowing the rate of environmental decline.

Furthermore, complex foodwebs in northern oceans, particularly around Europe and North America (where most PCBs were produced and used) are undergoing subtle alterations. Predators like sharks, large fish or killer whales are changing their diets and exploiting new prey, which in turn alters their exposure to PCBs and other contaminants.

PCBs are here for some time to come

What can be done? Unfortunately, the horse has bolted as such and it would be implausible to remove “background levels” of PCBs from the world’s oceans.

The key objective now is to maintain surveillance of these chemicals, whether they be in air, water, soil or animals. In most developed countries, end-of-life action ensures that old industrial materials with PCBs are subject to high temperature incineration (an effective way of ensuring complete destruction). Similarly, grossly contaminated industrial sites or dumps are subject to expensive clean-up and incineration activities.

But, while this is effective and safe at a local level, such measures will account for only a very small fraction of the total PCB inventory, most of which is out in the wild. International efforts by organisations like the UN Environment Programme (UNEP) are ensuring that member states are undertaking “stocktaking” activities, containing old storage or dump sites, and undertaking monitoring programmes. This is particularly important across parts of Asia and key states of the former Soviet Union, where PCB production and use was also high.

The legacy of PCBs will continue to haunt us for some while to come. Scientists estimate that the final resting place or “sink” for PCBs is likely to be organic rich soils across the Northern Hemisphere or even ocean sediments. However, in the meantime, PCBs continue to cycle around the environment and are still present in mother’s milk. Maternal transfer from adult female to calf is the key exposure route for most marine mammals and this chemical stress (supplemented by an array of chemical pollutants other than PCBs), alongside climate change induced stress, is a major concern.

Crispin Halsall, Reader in Environmental Chemistry, Lancaster University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Top header image: timnutt, Flickr

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Earlier this week, a team from the Dolphin Encountours Research Center responded to reports of a stranded humpback whale on a beach in Ponta do Ouro, Mozambique. When the crew arrived on the scene, the whale – believed to be a juvenile – was lying motionless in the shallows while a crowd of onlookers steadily grew.

With the assistance of Dr Jennifer Olbers from the KZN Marine Stranding Network, an assessment was carried out and it was determined that the humpback was in a poor state. Unresponsive, riddled with lice, and struggling to breathe, the whale had little chance of survival and a tough decision was made to let nature take its course.

Fillimone Javane, a guard for the Ponta do Ouro Partial Marine Reserve (PPMR), together with his team, helped relay information to the gathering masses, while citizen scientist and founder of the Dolphin Encountours Research Center, Angie Gullan, got to work collecting samples and taking measurements.

Once data had been collected, the team – facing growing pressure from onlookers – decided to allow meat to be harvested from the humpback. "It was made known that we did not know why the whale had died and consumption of meat was at one's own risk," Dolphin Econtours Research Center wrote in a press release. 

With much of the carcass removed, the incoming tide brought with it a number of sharks. Warnings have been issued to bathers in the area.

This is the 26th stranding that has been recorded in the Reserve since the organisation began operating in the area.

Header image: Earth Touch, 2014

“I have swam with other species of whales in the past, but besides doing my deepest dives to 106 metres, this was the best diving experience of my life,” Stern told us via email. Tonga, a cluster of rainforest-covered islands scattered in the South Pacific some two-thirds of the way from Hawaii to New Zealand, is one of the few places in the world where tourists can responsibly dive with whales. Stringent rules ensure that only licensed whale-watching operators are permitted to approach the humpbacks as they make their annual migration from feeding grounds in Antarctica to tropical Tonga waters where they mate and give birth.

Most of the whale-watching vessels in the area operate around a collection of islands called Vavaʻu; however, Stern and his group opted to beat the crowds and were exploring more southerly waters around Nukuʻalofa off the island of Tongatapu when they bumped into a curious humpback. “This one actually caught us by surprise!” Stern explained. “We were in the water to listen to them singing – because there were no whales around at the time – and then this one just appeared.”

Humpback sightings in Tonga start surging in July each year as the “Tongan Tribe” – a moniker given to the whales that frequent the area – makes its way along the submerged volcanic arch that forms the bedrock for Tonga’s 170-plus islands. Rampant whaling in the twentieth century decimated Oceania’s whale populations and the Tongan Tribe in particular is believed to have suffered significant casualties.

The King of Tonga put a stop to all whaling operations in Tongan waters in 1978 and humpback populations in the area have slowly risen over the last 40 years. However, unlike the populations in Australia, they are yet to reach pre-whaling highs. Conservationists are hoping that the thriving whale-watching industry in Tonga can help bolster the numbers.

“Responsible whale and dolphin watching is a win-win solution for whales and people in Tonga, and has the potential to provide important economic opportunities to the people who live there,” IFAW Pacific Officer, Olive Andrews stated in a press release regarding the role that whale watching plays in the Tongan economy. “Whales are clearly worth far more alive than dead.”

Many people who have swum with humpbacks would likely agree with Andrews’s sentiments. According to Stern: “Swimming with humpbacks is actually quite emotional. It's incredible to see something so huge in the water and even more incredible when that giant creature is interested in you. The whales would swim and play with us. It surpassed all the expectations that I had before going on the trip.”

Although we prefer to steer clear of the negative connotations of the “killer whale” label, these apex predators sure are skilled at taking down their prey. Simon Pidcock of Ocean EcoVentures Whale Watching was trailing a pod of orcas in Canada’s Cowichan Bay off the coast of Vancouver recently when the black-and-white hunters set their sights on a pair of harbour porpoises. Pidcock was lucky enough to capture some incredible footage of the hunt:

Orcas have a formidable array of hunting strategies at their disposal, but one of their more impressive tricks involves launching prey into the air – a tactic that one of these orcas employed when it briefly breached, forcing a porpoise to take to the air as it struggled to escape the pursuing predator.

"This one was very very aerial," Pidcock told Chek News. "They really try to wear down the porpoise they'll ram it down from underneath really launching it into the air.”

The orca pod split into two groups each pursing a porpoise – chasing their prey for some time before finally dispatching of it, Pidcock explained.

Like other whales, orcas belong to the order Cetacea, but these toothy behemoths are actually the world's largest oceanic dolphins (and members of the Delphinidae family). Three distinct “varieties” of orcas can be found cruising the waters around British Columbia, but the porpoise-hunters in this video are known as "transient” or Bigg’s orcas. They differ from their close cousins in that they live in much smaller groups and specialise in hunting other marine mammals like seals and porpoises.

Porpoises are common prey for these mammal-munching orcas, however, capturing footage of a hunt like this is rare. "Transient or Bigg's killer whales are relatively stealth whales – certainly when you're the top predator it doesn't make sense to advertise your presence," biologist Anna Hall told Chek News.

Orcas rank among the ocean's most efficient hunters. Weighing in at over 10 tons, armed with a mouth full of sharp, interlocking teeth, and capable of reaching speeds close to 35mph (56kph), these expert predators can kill with remarkable effectiveness.

Transient orca activity is on the rise off the Vancouver coast as many prey species are giving birth – attracting a bevy of opportunistic predators. According to Hall, the oceans become their playgrounds at this time of year – good news for whale watchers, bad news for porpoises.

Top header image: timnutt, Flickr

A group of tourists off the coast of Port Macquarie in New South Wales were recently treated to – and drenched as a result of – a spectacular close-up encounter with a humpback. After a pod of whales were spotted in the distance, tourist Tash Morton - eager to capture some footage of a leaping leviathan – began recording the action.

Morton got a lot more than she was expecting. A whale launched itself out of the blue just metres from the boat, and crashed back into the water with an almighty splash, drenching almost everyone on board. “I wanted one video, however, [I] did not anticipate getting the magical shot I got,” she told ViralHog.

According to whale watch operator Anthony Heeney it’s not uncommon for whales in the area to approach boats. “We've had them close before when they have interacted and come over and swum under the boat and spy hopped beside us," he told ABC News.

"The whale was probably about the same size as the boat,” he said describing the recent close encounter. “We're 10.5 metres and about 5 tonne, I'd say that whale was the same length as us but about 10 or 15 tonne.”

Port Macquarie is renowned as a whale-watching hotspot and regular sightings of humpbacks are the norm here as these behemoths migrate along the Australian coast. During the summer months, populations in the southern hemisphere can typically be found feeding in Antarctica. In late autumn the humpbacks head north to their winter breeding and calving grounds in the tropical waters of the Pacific.

There have been several whales sightings in the area in recent weeks, however, none quite so dramatic as this!

That's how diver Ben Laboy describes his recent encounter with an inquisitive gray whale in California's Monterey Bay. The animal surprised Laboy when it materialised behind his dive partner, but he managed to bottle up his excitement until the behemoth faded from view, as swiftly as it appeared. (It's hard to believe this was Laboy's first time diving with a GoPro!)

"I will never forget looking into the eye of this majestic animal," Laboy wrote on Facebook, noting the whale came within feet of him and his dive buddy, Nicole Guido-Estrada.

Despite being just an arm's length away, neither diver attempted to make contact with the passing giant. (It was the right move: intentionally touching – or even approaching – whales can be dangerous, and it's also illegal in US waters). 

A few high fives and underwater squeals later, the pair returned to the surface and excitedly shared their footage with staff at the Monterey Bay Aquarium (MBA). The team estimated the whale in Laboy's video was well over nine metres long (30ft) long. Adult gray whales can reach 15 metres (50ft), so despite its impressive bulk, this individual was still a young gun by those standards. Adults reach sexual maturity at only eight years, and live to be around 40.

"This took place a stone's throw from the Aquarium's back deck," Aquarium staff wrote in a Facebook post accompanying the clip. "It's perfectly poetic that Ben and Nicole came across this wandering whale off of McAbee Beach, once home to a whaling station and now host to impromptu underwater whale-watching."

Like so many of their close kin, gray whales were hunted almost to extinction between the seventeenth and twentieth centuries, but decades of conservation work have seen this species stabilise, with around 20,000 individuals now in existence. Many of those whales are currently en route south along North America's Pacific coast, towards breeding lagoons in Baja California, Mexico. That lengthy migration begins in the Bering Sea, so the animal in Laboy's clip had likely travelled over 3,000 miles to arrive in Monterey Bay

"Not so long ago, this proud parade of gray whales was nearly lost to history," the MBA team said. "Today, spotting them on their migration is commonplace up and down the coast. You're bound to see a few spouts as signals to this conservation success story."

With any luck, Laboy's curious visitor will reach Baja in the coming weeks, where it will join in on the "fun" in the region's warm shallows.

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Top header image: Joe McKenna/Flickr

The clip was filmed on Auckland's Waiheke Island by local resident Shane Watt, who witnessed the action play out from his waterside home. 

It's plain to see (and hear!) that the bathers were more than a little rattled by the whales' approach, but local experts believe the children were in no real danger. 

"The kids were obviously very frightened," Watt told TVNZ. "It took us a minute to calm down afterwards so I can't imagine what the adrenaline would've been like for them."

It's not unheard of for orcas to make an inquisitive approach (or even to charge) towards potential prey or anything that appears out of the ordinary in their environment – only to slow down and adjust course upon realising that the object of interest is not on the menu. 

According to marine guide and Whale Rescue co-founder Jo "Floppy" Halliday, who has been working with cetaceans in New Zealand for over 20 years, it's precisely this kind of investigative swim-by we're seeing in the video. And there's no evidence to support claims by some commenters that the whales were "stalking" the children. 

"Sometimes they're echolocating; they're seeing something and that makes them curious," Halliday told Stuff New Zealand. "[The orcas] realised they were two little humans and just kept moving."

The two small – at least by adult orca standards! – males certainly stirred up quite the drama, however. Other bathers reportedly scrambled onto nearby rocks as the whales passed by, after initially mistaking them for extraordinarily large sharks. 

As for what the predators were doing so close to shore, it's likely that an influx of stingrays in the area brought them inland. Some New Zealand orcas are known ray-eating specialists, and past studies have shown they often hunt the potentially dangerous prey in tandem.

Learn more about the behaviour in our past coverage here!

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Top header image: Kenai Fjords National Park/Flickr