Southern right whale needs more protection, research shows

Southern right whales, or Tohorā, are something of a conservation success story, making a comeback from near extinction, but new research shows more needs to be done to protect their habitats in Aotearoa New Zealand waters.

A University of Auckland, Waipapa Taumata Rau study used four years of data on whale and vessel movements to check how well Marine Protected Areas (MPAs) limit the risk of deadly whale-ship collisions.

“Unfortunately, only about ten percent of the important southern right whale habitat was covered by Marine Protected Areas,” says Associate Professor Emma Carroll, the project lead.

In addition, combining whale locations and vessel tracking data for the peak breeding period from June to October, showed a 'high' level of overlap between whales and vessels within several MPAs, showing the whales can remain vulnerable even in protected areas.

Commercial whaling in the early 19th century reduced the population of southern right whales from approximately 30,000 to an estimated 30–40 mature females around 1920. Today, there may be 2,000 of the whales in New Zealand waters.

“As this population is slowly recovering, we are seeing more whales in southern waters,” says Dr Leena Riekkola, the senior author of a paper just published in the Journal of Environmental Management.

Tracking 29 whales tagged at the subantarctic Auckland Islands/ Maungahuka between 2009 and 2022 revealed two previously unknown and currently unprotected areas used by the whales for important behaviours such as foraging, socialising or resting.

MPAs are legal tools that can impose restrictions such as bans on fishing.

In comparison with the ten percent level of MPA coverage, nearly 60 percent of the whales’ important habitat is covered by the international classification of `Important Marine Mammal Area’, a designation indicating the need for conservation measures.

“This indicates there is insufficient legal protection for the whales from human activities,” says Dr Carroll.

The complexities of protecting marine mammals include animals changing their locations as waters warm.

Tools for aiding in whale conservation amid ongoing increases in shipping levels could include extra MPAs imposed for only key times of the year, such as breeding seasons, or speed limits for ships, or observers on ships to spot whales, the research authors, who were led by Xuelei Zhang, suggest.

The research was funded by the Royal Society Te Apārangi Rutherford Discovery Fellowship, Live Ocean, Lou and Iris Fisher Charitable Trust, Joyce Fisher Charitable Trust, Brian Sheth/Sangreal Foundation, UOA Science Faculty Research Development Fund, International Whaling Commission – Southern Ocean Research Partnership, Antarctic and Southern Ocean Coalition, DOC, and the Cawthron Institute.

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