Whales Found Dead Under Australian Warship in San Diego May Have Been Mother, Calf

An Australian Navy ship has been linked to the "tragic" deaths of two endangered whales in southern California, which may have been a mother and her calf.

The bodies of two fin whales surfaced after becoming dislodged from the hull of HMAS Sydney as it berthed alongside Naval Base San Diego on Saturday morning, NCA News Wire reported. The destroyer warship has been holding joint exercises with the U.S. Navy in the area since last month.

The U.S. Navy, the Royal Australian Navy, National Oceanic and Atmospheric Administration (NOAA) Fisheries and other bodies are working to review the incident, the Australian Department of Defence said in a statement sent to Newsweek.

"The navy takes marine mammal safety seriously and is disheartened this incident occurred," it said.

The animals were fin whales, NOAA told Yahoo News Australia. The carcasses, measuring 65 feet and around 25 feet in length, respectively, were later removed from the water. Yahoo News Australia reported the whales may have been a mother and her calf, with the bigger whale taken out to sea. Samples have been taken from the whales to confirm if they were related.

Vessel strikes are the biggest threats to these endangered animals, which can live up to 90 years and grow up to 85 feet. Other threats include fishing gear—which the whales can get tangled in—depleted prey due to overfishing, and noise in the ocean. An estimated 3,200 whales inhabit the waters of the eastern Pacific Ocean, including California.

John Calambokidis, a research biologist at the Cascadia Research Collective in Washington who is an expert in whale and ship strikes, told ABC affiliate 10 News the incident was "sad, but it's also not surprising."

Calambokidis said this is the first case he is aware of where two whales have been discovered at the same time, and said the pair may be mother and calf judging by their sizes. He said ships are generally unaware that they have hit a whale. Up to 50 fin whales are hit each year in this area, he said, although fewer are reported.

Lucy Babey, head of science and conservation at U.K.-based whales, dolphins and porpoises charity ORCA, made a similar assessment regarding their relationship. She told Newsweek mother fin whales nurse their young for up to seven months, most often just under the water's surface.

Fin whales are at greater risk of being hit by ships due to their size, and because they rest and breathe near the surface of the water, according to Calambokidis. After blue whales, they are the second-largest species of whale.

Babey said a mother and calf pair would be at a greater risk of ship strikes as calves cannot hold their breath for long periods to dive, and therefore remain near the ocean surface most of the time.

Danny Groves, communications manager of U.K.-based charity Whale and Dolphin Conservation, also told Newsweek it appears the whales were a mother and calf.

Groves said large passing ships are unlikely to see a whale, and may not be able to change course if one is spotted. Large ships create what is known as a "bow null effect," where the bow blocks engine noise. This creates a quiet zone in front of the vessel, "leaving a whale unaware of the pending threat," he said.

"Sometimes a whale can surface abruptly for air or swim just feet below the surface with barely a ripple visible to alert passing boaters to their presence.

"While a number of technological efforts have been researched to reduce the risk of striking whales, none have yet proven viable. Some may even increase risk to whales, as they respond by surfacing, putting them further in harm's way. The most effective means to reduce collisions between whales and vessels is to separate them, and when that can't be done, slow the vessel down to a speed of 10 knots or less."

Patrick Ramage, senior director at International Fund For Animal Welfare (IFAW), described the deaths as "tragic" to Yahoo News Australia, and said military ships are like "floating skyscrapers" when compared with fin whales. He said the whales died despite the fact underwater monitoring equipment is used to try to reduce the risk of such incidents.

"It's not the first time that an Australian Navy vessel has struck a whale, and certainly it's something that other navies including the U.S. Navy have had to contend with, as they move sometimes at high speed through critical habitat areas," he said.

"Speed kills almost irrespective of size of vessel, but when large vessels are moving through critical habitat areas, such as off southern California right now, where a lot of fin whales and other species are feeding, it can be a lethal combination."

Following the incident, Australian Senator Peter Whish-Wilson tweeted: "This is a timely reminder of our impacts on the oceans and precious marine life.

"Ship strikes often go unreported and undetected. We must learn from this so we're better informed to prevent such devastating events from happening in the future."

This article has been updated with comment from Lucy Babey and Danny Groves.