Sealions 2: The Reply

A while ago I wrote about Hon. Jim Anderton's decision to increase the Sea Lion kill quota so that we could all eat more squid. I wrote him an email asking a few questions. On the weekend he replied (I've been sick so that's why you get it now). Before I put the letter up have a quick glance at this.

Japan has a whaling surplus. They have caught more whales than the market desires. While this may stengthen claims that whales can be fished (how ironic) sustainably, it shows more that the Japanese have an over-inflated estimate of the market size. Given how you hunt whales you can acurately control the size of the catch and do not have to overfish.

I have a feeling Che Tibby might like this development.

Anyhow here's the Minister's reply:

Dear Hadyn Green

Thank you for your message of 26 April seeking some detailed technical answers to the way in which the kill quota for sea lions was calculated. I have asked the officials concerned to have a look at your questions, and the answers are:

1. What actual numbers you used to justify the increase in the number of sea lions that could be killed?

The sea lion mortality limit resulting from harvest control rules applied to the Breen-Kim model is set according to theoretical maximums and minimums to ensure sustainability of the population over 100 year runs simulated in the model. For the 2005-06 fishing year, the range available to me runs from 0 to 550 sea lions. Within this range, my decision was to increase the current limit from 97 to 150 sea lions. Note that this level of bycatch is still at the lower end of this range.

In addition, I considered current squid catch rates, and associated economic values associated with foregone fishing opportunities projected if the Auckland Islands squid fishery (SQU 6T) were closed to trawling upon reaching the previous 97-animal FRML.

2. What is your model for the New Zealand Sea Lion population and what are the trends predicted for the next three years?

The Ministry of Fisheries has invested significant resources into a scientific model of the sea lion population developed by NIWA scientists Paul Breen and Susan Kim (the Breen-Kim model). The Breen-Kim model was developed to ensure management of the sea lion population remains above 90% of its carrying capacity, or remains about 90% of the level it would obtain in the absence of fishery bycatch, 90% of the time. The model does not predict future trends in sea lion population, nor does it prescribe a specific bycatch limit. Rather, bycatch control rules are assessed with the Breen-Kim population model based on current annual pup production numbers to determine the range of acceptable fishing-related mortality limits for a given year that satisfy the sea lion management objectives noted.

A more detailed discussion of the B-K model and its application in assessing alternative sea lion bycatch management options is provided in consultation documents and advice papers concerning the 2005-06 SQU 6T sea lion operational plan. These documents are available on the Ministry of Fisheries website at http://www.fish.govt.nz/sustainability/impacts.html.

3. Are you confident in the model, and if so, why?

The Ministry of Fisheries advises me that the Breen-Kim Model provides the best available information to assess the incidental capture of sea lions within the SQU 6T fishery under a range of bycatch level scenarios. This model was developed under the scrutiny of the Ministry’s Aquatic Environment Working Group in 2003 and was independently reviewed in 2003.

The Breen-Kim model incorporates the available biological information on the New Zealand sea lion population and dynamics. The Breen-Kim Model uses the best available data, and models a range of parameters to represent the current state of knowledge of sea lion biology and demography as accurately as possible.

4. Where do the numbers for your model come from and how often are they updated?

Breen and Kim developed a model in 2003 to assess the New Zealand sea lion population using a fully-age-structured Bayesian approach. The model takes into account the full range of biological and fisheries data available, including observed maturity schedules, variable pupping rates, vulnerability at age information from by-caught animals, survival rates, and late season pup mortality data. The alternative decision rules use pup production estimates as an index of population size, as direct estimation of numbers of adult sea lions is hampered by their periodic foraging trips at sea.

The Breen-Kim model was formulated from these biological and fisheries data up through 2003. Subsequent modifications of the model were made in 2004. Pup production in a given year is incorporated in calculations of allowable sea lion mortality levels under the alternative decision rules. I am mindful that it may be appropriate to update the sea lion population model, to include information that has become available since 2003.

5. Has the sea lion population increased at a rate sufficient enough to warrant a kill quota increase of 55%?

The Breen-Kim sea lion population model is used to test alternative bycatch decision rules. For the 2005-06 fishing year, the fishing-related mortality limit range available to me runs from 0 to 550 sea lions. Within this range, my decision was to increase the current limit from 97 to 150 sea lions. Note that this level of bycatch is still at the lower end of this range.

6. Why are alternative methods of squid fishing not being promoted?

Fishing vessels are currently permitted to use the method of jigging in all New Zealand squid fishery management areas, including the Auckland Islands SQU 6T. However, operators have not undertaken to fish for squid using jig methods in the SQU 6T fishery since the early 1980s when there were some trials conducted. The number of jig vessels active in New Zealand waters has also declined substantially, from over 100 boats in the 1980s, to about 15 squid jigging vessels at present. Less than 10% of the allowable squid jig catch has been achieved in recent years.

With specific regard to SQU 6T, available information indicates that ocean conditions around the Auckland Islands can be both difficult and hazardous for squid jigging vessels. For this reason I am unwilling to require extended no-trawl zones around the Auckland Islands in order to encourage jigging alternatives until such methods have been further tested and proven feasible in this fishery.

The Ministry of Fisheries is encouraging the squid industry to trial the method of jigging in the Auckland Islands fishery in light of technology used in some overseas squid fisheries. In addition, trawl fishers employ various management practices, including the use of sea lion exclusion devices (SLEDs) to avoid the unintentional deaths of these marine mammals in the SQU 6T fishery.

7. Will the sea lion kill quota be raised every time there is an increase in squid numbers?

Prior to making my decision to increase the FRML to 150, indications were the current harvest limit for squid would be substantially under-caught unless the FRML was increased in relation to sea lions. I was advised that increasing the FRML on a one-off basis to 150 sea lions was likely to be sustainable. On balance, then, and on the basis of the best professional advice available to me, I considered the increased risk to sustainability of the sea lion population to be acceptable as a result of this increase in the FRML.

My decision to increase the FRML on a one-off basis is not intended as a precedent; rather it reflects ongoing considerations in balancing my obligations under the Fisheries Act to provide for utilisation while ensuring sustainability. Both squid abundance and allowable sea lion bycatch are subject to change and uncertainty over time.

8. What criteria have to be met to justify an increase in the sea lion kill quota?

The Fisheries Act 1996 specifies obligations for setting a limit on sea lion mortalities, but not explicit criteria for increasing or decreasing the limit. Section 15 of the Fisheries Act sets out the Minister of Fisheries’ role in managing the effects of fishing on marine mammals or other wildlife depending on whether a Population Management Plan (PMP) exists. A PMP is developed under the Marine Mammals Protection Act 1978, and is approved by the Minister of Conservation (after concurrence from the Minister of Fisheries). There is no PMP for the New Zealand sea lion at present.

Without a PMP, the Fisheries Act provides alternative mechanisms to manage the effects of fishing-related mortality on the New Zealand sea lion. In particular, s 15(2) states that in the absence of a PMP, the Minister of Fisheries, after consultation with the Minister of Conservation, may take such measures as are considered necessary to avoid, remedy or mitigate the effect of fishing-related mortality on any protected species and this may include setting a limit on fishing related mortality.

The criteria and rationale for the FRML in a given season is contained in the SQU6T sea lion operational plan. This plan specifies management objectives and procedures to meet these obligations based on the best information available.

I trust this covers the points you have raised, but if it does not then please write to me further and I will do my best to answer your queries.

Yours sincerely

Jim Anderton
Minister of Fisheries
M P for Wigram and Leader of the Progressive Party