KAHAWAI MANAGEMENT PROPOSAL 1990

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KAHAWAI FISHERIES IN NZ

Summary
Kahawai have come under increasing pressure by both commercial and non-commercial interests over recent years. The rise in commercial catches from 4974 tonnes in 1983 to 9981 tonnes in 1988 is of major concern to recreational and Maori interests as this increase has coincided with a reported decline in the availability of kahawai to these groups.

In order to ensure that kahawai is properly managed so as to provide for its sustainability, it should be brought into the Quota Management System. Since the Government has decided not to issue new quota in perpetuity, kahawai would therefore be subject to Term Transferable Quotas (ITQs). This will require legislative change. In the meantime, it is proposed to set Quotas for the commercial fishery. These would be fished competitively. It is proposed that the Quota be apportioned between fishing methods and four Quota Management Areas to provide improved management for this species.

The purpose of this discussion paper is to seek the views of all interest groups in the kahawai fishery on the level of Quota and the distribution of this between areas and fishing methods.

1. Introduction
Kahawai, Arripis trutta, are a schooling fish found throughout New Zealand coastal waters including around the Chatham Islands. They are most abundant around the North Island and northern South Island. Exploitation of kahawai dates from the early settlement of New Zealand where they formed a significant food source for Maori. They are renowned for their excellent fighting qualities as a sports fish by recreational fishers using light tackle, and have recently been recognised as a trophy fish by the International Gamefish Association. Commercial catches have increased since 1983, from 4974 tonnes to a peak of 9981 tonnes in 1988. Most of this increase has been by purse seine (Table 1).

Kahawai are most often seen in surface schools along the coast and around river mouths. These loose to densely packed surface schools can range from only a few hundred fish up to schools of several thousand tonnes, but most schools contain between 10-40 tonnes of fish. As a schooling fish, they can provide large catches when schools are located and successfully captured, which makes them particularly vulnerable to commercial fishing pressure using bulk fishing techniques such as purse seine.

Kahawai are predators feeding heavily on surface living animals such as krill, anchovy, mackerel and pilchards. Although often seen feeding on the surface when schooling, they are also known to feed near the sea bottom. Kahawai have a moderate growth rate, reaching a length of about 15cm by the end of their first year and 35cm by the fourth year. Kahawai may reach lengths over 60 cm and ages of 20-26 years. They spawn in both open and sheltered inshore waters during January to April, the juveniles being commonly found in sheltered coastal waters and estuaries of the North Island, particularly those between North Cape and the Bay of Plenty.

By the end of their first year kahawai gradually move into deeper water; adults may be found in waters out to depths of 100 metres or more. Throughout their life kahawai school by size, juvenile schools being of single ages but adult schools containing mixed ages. Frequently they school with other fish especially mackerel, trevally and kingfish. Large schools of adults may enter river mouths at high tide from December to April. During the winter kahawai are more common in deeper waters.

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2. Maori Fisheries
Exploitation of kahawai dates from the early settlement of New Zealand when they formed a significant food source for Maori. In pre-European times they were most often taken by paua shell lures which were trolled through schools of fish. Large catches were often dried or smoked and stored for later use or used in trade with other tribes and later with Europeans.

Extensive Maori use of kahawai continues today in many locations, particularly the seasonal runs in river mouths such as in the Motu River in the eastern Bay of Plenty. Large catches are still preserved for later use by smoking or bottling.

3. Recreational Fisheries
For several years kahawai have been attracting increasing recreational interest. Recreational surveys have shown it is the second most popular fish taken by recreational fishers in New Zealand after snapper. The major rivers on the east coast of the South Island and some of the larger rivers in the North Island support significant fisheries. One of these, the Motu River, is possibly the most productive of these with an estimated catch of over 15,000 fish taken in the four month season during 1982. In the South Island, surveys have shown that 3-4000 fish are taken from the Waitaki River mouth alone each year. Kahawai is now established as a light tackle game fish.

Kahawai are inshore surface-schooling fish and are easy to catch. They are therefore a species that has a high public awareness. Many are caught by trolling lures through surface schools. In Northland, in particular, they are used as bait for the big game sports fishing industry. Further uses of kahawai along the coast are by tourists both for fishing and in passive recreation through the visual attraction of large schools of fish.

4. Commercial Fisheries
Until the 1970s the commercial catch of kahawai was low with recorded catches less than 300 tonnes taken annually, most of which was used as bait in rock lobster pots. In the mid 1970s purse seine vessels started fishing for skipjack tuna around the North Island over summer months and for other pelagic species including kahawai during the winter. Initially, most fishing was undertaken in the Bay of Plenty and around Poverty Bay but by the late 197Os purse seining for kahawai during winter and spring months had extended to the Wairarapa Coast, into the Taranaki Bight and around the north and east of the South Island to Kaikoura.

Reported landings of kahawai rose from 1461 tonnes in 1977 to a peak of 9981 tonnes in 1988 and declined to 6001 tonnes in 1989 (Table 1). Around 80% of the total New Zealand catch each year is taken by purse seine vessels (Table 1). Reported landings for this fishing method rose from 3628 tonnes in 1983 to 6285 tonnes in 1987. Currently there are seven purse seine vessels involved in this fishery based at Tauranga and Nelson. Relatively small quantities of kahawai are also taken by set-net and by trawling. There are small target setnet fisheries mainly in Northland, the Hauraki Gulf and on the west coast of the North Island. Trawl catches are predominantly taken as a by-catch of target fisheries for other species. Since the introduction of the Quota Management System in 1986, there has been a general decline in the level of inshore trawling, particularly around the north of the North Island. Nationally, trawl catches of kahawai declined from 586 tonnes in 1983 to 263 tonnes in 1987.

In the past, reported landings of kahawai have understated the actual catch levels because, as a lower valued species, often it was dumped at sea or when landed recorded as "mixed fish". Recent reported commercial landings are detailed in Table 1, and with estimates of non-reporting of 'mixed fish' in Table 2. Additionally, it is estimated that prior to 1986 around 300 tonnes of kahawai were taken annually for rock lobster and longline bait by commercial fishers, and not recorded on fisheries statistics.

5. Current State of the Fishery
Reported commercial catches of kahawai have increased in recent years from 4974 tonnes in 1983 to 9981 tonnes in 1988 and since declined to 6001 tonnes in 1989. Catches have fluctuated from year to year, however there has been an increasing trend in commercial catch. The major commercial fishing method for kahawai is purse seining, with smaller quantities taken by set nets. Kahawai is also taken as a by-catch of other fishing methods.

Currently managed as a non quota species, kahawai are subject to few commercial fishing restrictions. There has been a limitation on new entrants to the fishery over recent years, but no constraints have existed on catches. The recent increases in landings reflect not only a greater commercial desirability for this species, but also the addition of a further two purse seine vessels to the kahawai fishery since 1986.

Recreational fishers are concerned that the increasing catches of kahawai by commercial fishers are threatening their access to this fishery. They report significant declines in catch rates, in average sizes of kahawai taken and in sightings of surface schools, particularly over the last two years in Northland, Hauraki Gulf and Bay of Plenty waters. MAF Fisheries does not have data which support this.

Kahawai are known to be relatively mobile and relatively long-lived, so that heavy fishing pressure in one area may have effects on abundance in other areas even some distance from the fishing location. Localised depletion of kahawai from bulk commercial fishing methods and conflicts between commercial and non-commercial use of the kahawai resource also need to be addressed in the future management of this fishery.

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6. The Need For Management Change
Recreational fishers state that the recreational kahawai fishery:

• has suffered significantly reduced catch rates because of increasing fishing pressure on the stock;
• has significantly declined in quality in recent years, both in size of the fish available and in abundance of fish;
• is no longer managed to provide recreational access to a reasonable share of the kahawai resource;
• is in conflict with commercial fisheries, particularly with purse seiners and set netters.
  

Maori consider that management of the kahawai fishery needs to recognise:

• that kahawai has been traditionally fished by Maori;
• that Maori share the same concern about reduced quality of fishing, sizes of kahawai and catch rates, as stated by recreational fishers.

7. Proposed Interim Management Of The Kahawai Fishery
It is proposed to manage the commercial fishery for kahawai by Transferable Term Quota. The introduction of this management regime requires a change to the Fisheries Act which is impractical in the short term. In the interim the following package of controls are proposed by the Ministry for consultation with resource users. It is aimed to introduce these changes by 1 October 1990.

1. Management Controls to Reduce Total Catches
   It is proposed to place Quotas on the commercial fishery for kahawai and that these Quotas be competitively fished.
   
   There is concern at the rapid rise in the commercial catches of kahawai in recent years in the absence of any information about the sustainability of the increased levels of catch. The MAF Fisheries policy for recreational fisheries has as one of its objectives 'to ensure that recreational users have access to a reasonable share of fishery resources'. The concerns identified by recreational fishing interests suggest that the recent rises in commercial catches for kahawai coincides with a decline in the availability of this species. This in turn suggests that a conservative stance to the management of the kahawai fishery is warranted until such time as further assessment information becomes available.
   
   If a strong interaction exists between the commercial and non-commercial fisheries for kahawai then it is appropriate that the fisheries management regime limits the potential for large shifts in fishing effort in this fishery. For this reason it is proposed that Quotas for kahawai be set for each of the Quota Management Areas shown in Figure 1. This distribution in particular recognises the interaction between the commercial and non-commercial fisheries for kahawai on the east coast of the North Island.
   
   To allow for the range in efficiency of fishing methods used to take kahawai, the Quota should be apportioned by fishing method. The reported catch of kahawai by method for the period 1983-87 is shown in Table 1. On average, purse seine accounts for 78% of annual kahawai catches with set-net being the second most important method used to take kahawai (11%). The division of the Quota by fishing method would be threefold on the basis of a separate Quota for purse seine, set-net and all other methods combined, as most other fishing methods take kahawai as an incidental by-catch of target fisheries for other species.
   
   There are no estimates of biomass of kahawai and estimates of available yield have to be based on past catches. For kahawai, a conservative Quota could be based on the average catches over the years 1983-86, a period during which the fishery was relatively stable and which was prior to the rapid rise in commercial catches. Average catch by fishing method and Quota Management Area for the period 1983-86 is shown in Table 3. It is proposed that Quotas be based on this distribution of catch. Higher catches may be taken on a sustained basis however MAF Fisheries has no data which provide estimates of the upper level of sustainable catches.
   
   The tonnages for the four Quota Management Areas (Table 3) would represent significant reductions in catch from current levels in QMA1 and QMA2 (Table 2). The tonnage for QMA9 (490 tonnes) would be considerably higher than current catch levels if based on the average 1983-86 catches. If a conservative stance to the management of the kahawai resource is adopted it may be appropriate to reduce this to 200 tonnes to reflect current catches.
   
   Either of the previous options would probably represent a conservative catch level since there is little stock assessment evidence other than anecdotal reports of reduced recreational catch rates to suggest whether or not the current commercial catch level is sustainable. The increases in commercial catch have been rapid and the implications of current catch levels are not clear because of the lack of stock assessment data for this species.
   
   An alternative option is to establish Quotas for each Quota Management Area on the basis of recent commercial catches. The most recent annual commercial catches are 9981 tonnes for 1988 and 6001 tonnes for 1989. The Ministry does not have firm scientific evidence on which to base an argument on stock conservation grounds that Quota should be less than recent reported catches. If lower Quotas were to be set, then it would be on the basis of other fisheries management considerations.

Options:

1. Setting Quotas for kahawai for QMA1, QMA2, QMA3 and QMA9 based on average catches for each area for the period 1983-86.
2. As above, however with a reduction in QMA9 to reflect current catch levels to 200 tonnes.
3. Setting Quotas for four QMAs based on the most recent reported commercial catches.
   

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2. Input Controls
   While it is Government's preference to manage fisheries by output controls it may be that those proposals are not sufficient for this fishery. If this is the case the following input controls could be considered.

• Size of kahawai
  It may be appropriate to consider introduction of a minimum legal size for kahawai to improve the yield per recruit for the fishery or quality of recreational fishing.
• Localised depletion
  It may be appropriate in some areas to exclude certain commercial fishing methods for kahawai from areas of high recreational interest. Such proposals could be advanced through the fishery management planning process.
• Distribution amongst recreational fishers
  The distribution of kahawai among the recreational fishers may be improved by further limiting daily recreational limits. The need for this control could be regionally determined through the fishery management planning process.
• Reduction of conflict between recreational and commercial fishers
  If it is appropriate to have controls further to those above, then these could be addressed in the Fishery Management Plan for each Fishery Management Area.
• Concern about fishing methods
  Several cultural issues of concern to Maori have been identified and need further discussion before management solutions can be proposed.

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8. Summary Of Management Proposals

1. It is proposed that the commercial fishery for kahawai be managed by Transferable Term Quota. In the interim it is proposed to place Quotas on the commercial fishery for kahawai in New Zealand on 1 October 1990. It is further proposed that:

1. Quotas be set for each of the four Quota Management Areas shown in Figure 1
2. Quotas be competitively fished with separate Quotas for purse seine, set-net and all other methods combined.
3. Either:

1. Quota for each Quota Management Area be based on average catches for each area for the period 1983-86 (as shown in Table 3)
   or
2. As above with a reduction in Quota Management Area 9 to current catch levels.
   or
3. Quotas be set at the most recent levels of reported commercial catch.
   

2. It is proposed that regional management of kahawai fisheries be provided through the fisheries management planning process.

9. Submissions
Submissions on the proposals should be made by 3 August to:
Regional Manager North
MAF Fisheries
PO Box 3437
AUCKLAND

Table 1: Reported domestic commercial landings of kahawai (tonnes); all methods combined for 1970-1982 and 1988-1989, and by method for 1983-1987.

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Table 2: Commercial catch (tonnes) of kahawai: reported as kahawai and as 'mixed fish'*(combined) by Quota Management Area for 1979-87.

Note: Estimates have been made of the kahawai component of reported 'mixed fish' landings by purse seine. This is illustrated in the following generalised example. The annual catch of a particular purse seine vessel may have been: - 500 tonnes kahawai, 300 tonnes blue mackerel, 500 tonnes jack mackerel, 200 tonnes trevalIy, 500 tonnes 'mixed fish'; total catch 2000 tonnes. The 'mixed fish' catch was subtracted from the total catch. Because kahawai accounts for 33.3% (500 tonnes) of the 1500 tonnes subtotal for the remaining species, it was assumed that kahawai accounted for 33.3% or 165 tonnes of the 500 tonnes of 'mixed fish'.


Table 3: Average kahawai catch (tonnes) for commercial fishing methods by Quota Management Area, for the period 1983-86.

Figure 1: Proposed Quota Management Areas for kahawai. (Note: QMA3 includes QMA3, 4, 5, 6, 7 & 8 combined).

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