Marine protected areas (MPAs) are found to provide insufficient or only partial protection from threats such as commercial fishing, according to a New Zealand study published on Friday.

Using a three-year data set on whale and vessel movements in southern New Zealand, including the subantarctic islands, a tracking study of 29 New Zealand southern right whales, which are often in the same place as ships concurrently, compared whales' locations with those of vessels during peak breeding periods, finding a high overlap inside MPAs.

The MPAs are one widely used conservation tool intended to reduce human activity pressures, particularly fishing activities. However, their effectiveness is rarely evaluated.

According to researchers from the University of Auckland, the whales have important socializing and nursery areas in the subantarctic Auckland Islands, and not enough of their habitats are captured by protected areas.

However, even within protected areas, the high overlap with ships makes whales vulnerable to human activities, and this will only increase with more offshore industry, said the study published in the Journal of Environmental Management.

"There is insufficient legal protection for the whales from human activities," said University of Auckland Associate Professor Emma Carroll, who is the project lead.

"Our research focused on how well MPAs in New Zealand waters encompass important southern right whale habitat and how well they protect the whales from vessel traffic," said the study's author Leena Riekkola.