The biggest hunt is in Taiji - a town in western Japan which was the subject of the Academy Award-winning documentary The Cove several years ago.
Two men - one a former US federal agent, the other a Taiji town councillor - are using very different approaches to try to end this so-called tradition.
When dawn breaks over Taiji at this time of year, the banger boats head out for the hunt.
They are called banger boats because the fishermen bang poles against their hulls to create an underwater wall of sound, which drives panicked dolphins towards the cove, and to slaughter.
Scott West is the leader of a team of Sea Shepherd activists who monitor what goes on in the cove - a narrow inlet where about 2,000 dolphin and small whales are killed every year.
"They now use a technique called pithing and this is where they will drag the dolphins by their tails up onto the rocky beach in the shallow cove area and drive a steel rod down through their spine," he said.
"But the steel rod is removed and then a wooden plug is put into the hole and then pounded into place with a wooden mallet, all for the intention of keeping the blood from filling the cove."
Every morning before dawn Mr West leads his team to the cove.
"Right now we're headed into the harbour to go and let the dolphin killers know they're being watched and to make their happy morning less happy," he said.
But the dolphin hunters are not the only ones being watched. Every morning when the activists arrive in Taiji harbour they are greeted by the police.
It is not just foreign activists who would like the slaughter stopped.
While the pro-hunting mayor and the fishermen refused to speak to PM, town councillor Hisato Ryono did agree to be interviewed.
He is against the hunt, not because it is cruel, but because he believes dolphin meat is poisonous.
"I read that the council would use the dolphin meat for school lunches," he said.
"So I did some tests of the meat and it was found that the mercury level in the dolphin exceeded the safe level."
In fact, the samples were so toxic authorities decided against feeding dolphin meat to school students and even advised pregnant women not to eat it.
Mr West says it is another reason to end the slaughter.
"They're poisoning themselves, they're poisoning their children - it's insane," he said.
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