The squid season in sub-Antarctic waters to the south of mainland New Zealand is in full swing.

And each week the Ministry for Primary Industries issues a detailed summary of the performance of the squid fishery in relation to an operational plan to manage the incidental capture of New Zealand sea lions.

It includes the number of vessels, the number of trawl tows, the percentage of tows where MPI observers were present and mortalities.

The weekly report is widely circulated to all stakeholders, including environmental groups.

No one can credibly claim the fishery is not closely monitored or that any sea lion mortalities are covered up.

Last season that was not an issue in any case.

There were no recorded sea lion deaths. That was confirmed by the independent observers. That observer coverage was nearly 100 percent.

This year, 16 weeks into the season, regrettably, there have been three sea lion mortalities, one in March and two the week before last.

That was after a total of 1200 tows, which shows such captures are rare.

The Auckland Islands, 460km south of Bluff, are the sea lions’ main breeding grounds.

Last summer the annual Department of Conservation survey found a gratifying increase in pup numbers – up 14 percent on the previous year from 1727 to 1965 pups.

The main killer of pups is recognised as being the bacterial disease klebsiella pneumoniae. It was first noticed killing pups in 1998 and has since become endemic.

Pups also drown in deep holes in the peaty ground on the islands and wooden ramps are being installed to allow them to escape.

Claims the squid trawlers are robbing the sea lions of their food have been found to be incorrect.

Research by NIWA fisheries scientist Dr Jim Roberts has found the southern arrow squid make up less than 20 percent of the sea lion diet.

MPI’s 2016 Aquatic Environment and Biodiversity Annual Review recognised “there is no single threat that is impacting on the sea lion population and recovery will require mitigation of multiple threats at the four main breeding sites”.

The seafood industry acknowledges there is still work to do to mitigate its effects on the environment. Ongoing efforts are being recognised and they are proving effective.

These include the introduction of Sea Lion Exclusion Devices (SLEDs) which were introduced to squid trawls a decade ago to allow escape from nets.

These devices have markedly reduced sea lion mortalities.

Fishing activity in the stormy southern waters has  developed only relatively recently.

Distant water fishing nations, notably the USSR and Japan but also Korea, began targeting the southern ocean in the 1960s and the details of their catches and activities are sketchy.

Early research cruises included Japan’s Kaiyo Maru and Germany’s Wesermunde. 

Hoki, squid, ling, hake and silver warehou were the major species assessed.

Catches also included sea lions, 10 at the Auckland Islands from just 58 tows in one year.

The introduction of the 200-mile Exclusive Economic Zone in 1977, the Quota Management System in 1986 and the foreign charter vessel review effective in 2016 have all impacted on fishing effort.

The fleet is now much reduced and the number of tows are consequently lower. This partly reflects consolidation of quota and increasing vessel efficiency.

In the 1980s there were 40-plus squid vessels in the Auckland Islands region, whereas about 12 have been active in the last few years.

There is a similar trend in the southern blue whiting fishery further to the south around the Campbell Islands

Populations of sea lions and the seabirds endemic to the sub-Antarctic region are generally stable, or in several cases increasing.

Every effort is made to protect them so that commercial fishing and protected species can co-exist.

A threat management plan for sea lions is being finalised, boosted by a $2.8 million Government investment over four years.

The current population is just under 12,000 and a breeding colony is becoming established on Stewart Island, the first new settlement on the mainland for 200 years.