How much of the ocean is just whale pee? It's not true that the seas are salty because of whale pee, although a single fin whale can produce as much as 250 gallons of urine a day.
Admittedly, no one's worked out the exact volume urinating cetaceans add to the oceanic mix, but what marine biologists have recently revealed is that whale pee is crucial for healthy seas by moving masses of nutrients from place to place.
This largely happens through their migratory patterns, as baleen whales (filter feeders) habitually make long journeys between warmer and colder regions.
Female humpback whales, for instance, feed in the Gulf of Alaska and then swim thousands of miles to the Hawaiian archipelago to give birth.
This is because their newborn calves don’t have a thick layer of insulating blubber, so it’s important for them to start life in snug, warm seas. Meanwhile, the best places for whales to feed are the krill-rich waters of chillier, polar seas.
When whales set off for their breeding grounds, they generally stop feeding and metabolise the energy stored in their blubber. As a result, they release the nutrients consumed in the higher latitudes in their urine and faeces.
This horizontal flow of nutrients is known as the Great Whale Conveyor Belt.
Urine flowing along the conveyor belt is especially important. A 2025 study showed that grey, humpback and right whales collectively transport close to 4,000 tonnes of nitrogen every year.
Around the Hawaiian Islands, migrating whales roughly double the nutrients entering shallow seas.
All of this matters because nutrients stimulate phytoplankton growth, injecting energy into marine food webs.
This role was even greater before commercial whaling, when the amount of nutrients moved by the Great Whale Conveyor Belt was likely three times higher than today.
This article is an answer to the question (asked by Lou Grant, Birmingham) 'How much of the ocean is just whale pee?'
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