THE call came in last night: they’d found a body on the beach. We needed answers, and fast. I am out of the city within the hour, headed for the east coast and a rendezvous with investigator Rob Deaville.
But Deaville is no ordinary detective. And the body on the shoreline is a fin whale. As I arrive, the tide is receding, leaving the corpse high and dry. Fin whales are deep-water creatures, so it’s unusual to find one in the shallow waters of the southern North Sea. Deaville and his team have just a few hours to reconstruct its story and crack the case before decomposition and the tide take over.
Whenever a whale or dolphin is found dead on the shores of England or Wales, Deaville gets the call. Working for the , funded by DEFRA, he has done more postmortems on marine animals than he can count. You might think it sounds a depressing job, but he loves it. “Every case is fascinating and unique,” he says. “And so important.”
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Each year, about 600 whales, dolphins and porpoises wash up on British shores. About 50 of those are whales, and this is the fourth fin whale stranding this year. Most often it’s a single animal, sometimes two or three. There are myriad reasons why a whale might strand: it may be weakened by infection or starvation, or have been hit by a ship. . Sonar seems to lead whales to rise too quickly from deep dives, causing decompression sickness. Pollution takes a toll, too.
The number of strandings has been rising, Deaville tells me. Strangely, that’s a good sign. “There are more strandings because there are more whales out there,” he says. “Since the moratorium on whaling in 1986, populations have been gradually recovering.” Several species are seen regularly in UK waters, including humpbacks, minke and sperm whales. put the fin whale population in the eastern north Atlantic at around 25,000. That’s reasonably healthy, but still way below .
“Deaville advances towards the bloated belly with a spade-like knife”
Shortly after we arrive on the Norfolk coast, Deaville’s team takes down some particulars: the fin whale is female, 13 metres long and looks to weigh about 13 tonnes. That’s small. Adults can reach 26 metres in length and weigh 64 tonnes – they are the second-largest animals on Earth, after blue whales. This one is probably less than 2 years old, barely more than a calf.
The first thing Deaville notices is that the whale is extremely thin. He points to bumps along its spine. “The vertebrae should not stick out like that. It was probably starving,” he says. He also shows me signs of cuts and abrasions along the tail, indicating signs of a struggle on the beach: the whale was clearly alive when it washed up.
Starvation is not uncommon as a cause of stranding, but that can only be part of the story. Why wasn’t this whale eating? Fin whales are filter feeders that make deep dives, gulping in huge amounts of water. They squeeze it back out through their baleen, which traps any fish, crustaceans and squid. Deaville has found a clue. There is something badly wrong with the whale’s lower spine. It is bent, with a noticeable hump and signs of muscle wastage around it.
By now, local nature wardens have set up a makeshift cordon around the body. That’s a good thing, because the postmortem is about to begin. Deaville advances towards the whale’s bloated belly with a large, spade-like knife. I notice the other team members backing away and hastily follow suit as Deaville jabs the knife in. I’m told that . This whale has not been dead for long, so decomposition hasn’t made things worse, but enough evil-smelling gas is released to make me appreciate the breeze blowing off the sea.
Deaville cuts a rectangle in the whale’s side and, aided by a winch on the CSIP Land Rover, peels the skin away. The team then saws through the thick ribs, and a vast tangle of intestine spills out. Deaville examines the kidneys, liver, lungs, intestine and the whale’s three stomachs. He’s looking for signs of infection or illness. “Nothing is really standing out beyond the fact that it’s extremely thin,” he says.
The team takes samples of each type of tissue for further investigation. The blubber can be tested for pollutants, for example, and genetic analysis of skin samples can show which population this whale belonged to. The baleen, which is made of keratin and grows like hair, can be tested for carbon isotopes to build a picture of where the whale went during its life. Such findings inform conservation strategies. Previously, Deaville and his team discovered high levels of an organophosphorus flame retardant in stranded porpoises around the UK. That finding fed into a Europe-wide risk assessment that led to that industrial compound being banned.
The whale’s organs dealt with, Deaville examines the spine. “We can’t tell if the deformity is congenital or the result of some trauma – from what we can see, there’s no direct evidence of injury.” With the postmortem revealing nothing else unusual, Deaville is left to conclude that an inability to feed, brought on by the spinal abnormality, was the most likely cause of stranding and eventual death. So with tissue samples on ice and safely stowed, the team packs up and we all head home.
As the beach is part of Holkham National Nature Reserve, the body also needs to be taken away. But this is the job of a clean-up crew who will arrive in the next few days. After cutting the whale into half a dozen sections with chainsaws, they will use a digger to put those chunks into skips. Finally, the remains will be taken to a rendering plant and turned into various products, from oils to bone meal.
Despite Deaville’s sensible conclusions, I’m left feeling slightly dissatisfied as I head back to London. If the spinal deformity was congenital, why did the whale strand only now? Yet if it was caused by trauma, wouldn’t we have seen a sign of it? I wonder if we will ever know the whole story.
But a few days later, a breakthrough. A taken before Deaville’s team arrived. The whale was more upright on the sand, and visible on its right side just below the hump is a deep gash at a right angle to the spine. The smoking gun!
Smoking gun
“A ship’s keel could do that,” Deaville tells me. “That’s the most likely explanation.” It appears that the injury didn’t kill the young whale, but damaged it enough to limit its movement, preventing it from diving and feeding properly. Such an injury would also account for the muscle wastage. Starvation and stranding followed in days or weeks. Case closed? No one can say for sure, but it’s likely.
The International Whaling Commission has a working party looking into ways to reduce ship strikes on whales. One strategy is to avoid known migratory routes, but these are poorly understood for fin whales. Perhaps our whale’s fate will help improve the situation. We always need more data, says Deaville, which means every stranding must be recorded. So if you find a whale on the beach, . Deaville can take it from there.
Profile
Rob Deaville runs the UK Cetacean Strandings Investigation Programme, which coordinates the study of stranded cetaceans, marine turtles, seals and basking sharks around the UK coast. He is based at the Zoological Society of London
This article appeared in print under the headline “Once more unto the beach”
