The Japanese whaling industry is partially blaming the environmental group, Sea Shepherd, for its smallest catch of whales in years.
The fleet has returned to Tokyo with 570 whales, well below the target of about 850.
Institute of Cetacean Research spokesperson Glenn Inwood, told Morning Report the season was disappointing.
Mr Inwood said the whalers lost 31 days because of harrassment and interference by the Sea Shepherd group, but other factors such as bad weather also contributed.
A Sea Shepherd activist, Peter Bethune, remains in custody in Japan, after he boarded a Japanese whaling vessel in the Antarctic Ocean in February.
