Scientists claim fishers catch more marine mammals, not just fish

May 24, 2016, University of Otago
Scientists claim fishers catch more marine mammals, not just fish
Credit: Elaine Leung

Reports last week of serious under-reporting of fish catches in New Zealand fisheries and lack of prosecution of alleged perpetrators is mirrored in reporting of marine mammals bycatch, say University of Otago marine mammal experts.

Using Government documents and data just released to them under the Official Information Act, Associate Professor Bruce Robertson and Dr Stefan Meyer of Otago's Department of Zoology have revealed today that the Ministry for Primary Industries (MPI) only legally required the New Zealand fishing industry to report all instances of marine mammal bycatch as late as 2008.

This is despite 30 years earlier the Government making it a legal requirement for fishermen to do so under the Marine Mammal Protection Act (MMPA) of 1978.

"Perhaps not surprisingly, fishermen have consistently not reported instances of bycatch for New Zealand Fur Seals, common dolphins and New Zealand Sea Lions at the same rate as when Government observers are on vessels," says Dr Robertson.

"This means management of New Zealand's marine mammals has been based on incomplete information.

"Of major concern is that these practices apparently have continued since 2008 when MPI started policing marine mammal bycatch reporting by fishermen."

He added that these findings indicate that it is not just illegal practices such as fish dumping occurring in the New Zealand fishing industry. Importantly, this shows that the recent instance of marine mammal misreporting of two Hector's Dolphins as noted in MPI's Achilles Report is not an isolated instance.

"Our findings point to widespread, ongoing, illegal practices in marine mammal bycatch reporting. It seems that just like the fish dumping, MPI is not concerned with marine mammal management in New Zealand fisheries, especially given there have been no instances of fishermen being prosecuted.

"We back calls for expanding the recently-announced MPI inquiry into fish dumping to include issues with marine mammal bycatch reporting."

They also urged the Government to put marine mammal management back into the hands of the Department of Conservation and the Marine Mammal Protection Act.

They add that this level of non-compliance brings into question the environmental impact of fishing and also fishing industry accolades, such as the Marine Stewardship Council (MSC) certification of the New Zealand hoki fishery. MSC certification of the hoki fishery occurred in 2001, 2007 and 2012. For two certifications, MPI was not enforcing marine mammal bycatch reporting, so "presumably these certifications were based on incomplete environmental impact data of the hoki fishery."

Drs Robertson and Meyer assessed OIA data for the West Coast of the South Island hoki fishery between 2004 and 2013 by comparing the rate at which fishermen report bycatch to the rate for Governmental observer. They say the numbers are concerning; in many years, fur seal bycatch numbers reported by fishers in the absence of a Government observer were just a fifth to half the rate recorded by observers.

For all trawl fisheries nation-wide, the picture for fur seal bycatch is the same. Between 2008 and 2013, fishermen-reported fur seal bycatch was consistently less than the rate reported when an observer was present, noting that the observer coverage was low at only 11 per cent of fishing effort.

This is not just an issue for fur seals, but also for common dolphins on the West Coast North Island mackerel trawl fishery. Here, between 2000 and 2011, with only 22 per cent average observer coverage of the fishery, observers recorded 117 dolphin captures, but fishermen only reported five dolphin captures. Between 2008 and 2011, when MPI were policing bycatch reporting, the observers reported 42 captures to only 4 for fishermen.

"The same is true for New Zealand Sea Lions. Between 1996 and 2011, for 14 out of the 16 years, the fishermen-reported bycatch number (when an observer was not present) was below the 95 per cent confidence interval determined by bycatch modelling," says Dr Meyer.

"So it is clear, instances of bycatch were and still are not reported by fishermen working in New Zealand's fisheries, despite the MMPA and Fisheries Act making these actions illegal."

Explore further: Accidental dolphin capture a problem for trawl fishery

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