SWORDFISH IPP ANNEX 2

75. Swordfish (Xiphias gladius) is a surface and midwater (primarily midwater) dwelling, highly migratory species found in all tropical and temperate oceans and large seas. Genetic studies suggest that swordfish in the Pacific Ocean comprise several semi-independent stocks: a western stock, a northeastern stock, a southeastern stock and a central south stock that includes New Zealand waters.
76. Swordfish do not form schools or dense aggregations. They move with prevailing currents and are associated with convergence zones, strong thermoclines or underwater features such as seamounts and shelving banks. Male and female swordfish have different geographical and seasonal distributions depending on size. In New Zealand waters there is progressive increasing of the average size of swordfish for increasing latitude beginning at latitude 40 degrees south.
77. Adult swordfish are visual predators. Relying on their highly developed eyes to detect prey in water where light is poor. They use their rostrum (sword) to stun prey. They are diurnal feeders, spending daylight hours near the seafloor feeding on demersal fish, they move to the sea surface at night to feed on squid and pelagic fish.
78. Within Pacific waters, spawning takes place in tropical waters of the western Pacific Ocean and to a lesser extent the equatorial waters of the central Pacific Ocean. Swordfish are batch spawners, perhaps as frequently as every few days over several months. Eggs are spawned in the upper layers of the ocean and like the protracted larval phase are pelagic. Swordfish have a large reproductive capacity with egg production estimated to range from 1 to 29 million (68–272 kg females respectively).
79. Estimates of growth rate indicate very rapid growth during the first year to between 0.9-1 metre in lower jaw to fork length (LJFL) and 10-15 kilograms of weight, with growth rate progressively slowing with age. The differences in growth parameters between males and females are significant with females growing faster than males. Asymptotic length for males is 2.13 metres while asymptotic length for females is about 3.00 metres LJFL. The maximum size reported for a swordfish is 4.45 metres total length (includes the bill and furthest extension of the tail) and about 540 kilograms (Nakamura 1985). Swordfish reach sexual maturity at 5-6 years of age. Ward and Elscot (2000) report that Australian swordfish are moderately long-lived but apparently not beyond 25 years of age.

80. Two types of swordfish fisheries have been characterised:

1. Convergence fisheries; and
2. Topographic fisheries.

81. The swordfish fisheries of the North Pacific, the South Pacific off Chile and the South Atlantic are convergence fisheries. These fisheries are broadly distributed and associated with currents and fronts in the open ocean. In general, convergence fisheries are highly productive although productivity can be variable depending on local environmental conditions, such as the southern oscillation in Pacific waters.
82. Examples of topographic swordfish fisheries include Florida, Hawaii and Australia. Fishing occurs on particular features such as continental slopes, banks and seamounts. As they develop topographic fisheries are characterised by the fleet progressively expanding to new grounds. Initially these new grounds have high catch rates but local depletion can occur when swordfish are removed at a greater rate that that at which growth and immigration can replace them. It is not known for how long individual swordfish “reside” around underwater features. However, mixing throughout swordfish populations probably takes months if not years.
83. New Zealand has many of the characteristics of a topographic type swordfish fishery. The North Island blocks the eastwards extension of the South Pacific’s western boundary current. Consequently, the subtropical convergence zone is not as productive as elsewhere in the Pacific. In addition, as discussed further in paragraph 89, the New Zealand fishery has had to expand in area to increase swordfish catches.
84. The commercial landings of swordfish are presented in Table 2.
    

85. Before the start of any domestic fishery, distant water longline fleets were granted foreign license access to fish for southern bluefin and bigeye tuna (Japan) and albacore (Korea). The swordfish bycatch by the Japanese foreign licensed fishery averaged 388 tonnes per year between 1979-80 and 1992-93 with peak landings of 761 tonnes in 1980-81 and 681 tonnes in 1985-86. The Korean foreign licensed fishery reported only small catches of swordfish (0 to 7 tonnes per year). Most of the Japanese swordfish catch (85%) was from FMA 2 and FMA 9 while the Korean swordfish catch was mostly (79%) from FMA 9 and FMA 10.
86. Declining catches of striped marlin in the early 1980s led to the implementation of the “Billfish Moratorium in Northern Waters” in 1987. These regulations prohibited domestic commercial fishers from taking any billfish. In addition, fishing by foreign licensed tuna longline vessels was prohibited in the waters of the Auckland Fisheries Management Area (FMAs 1 and 9). As part of the regulatory provisions any billfish taken as bycatch could be tagged and released. The terms of the moratorium on billfish for domestic fishers were varied in 1993. The prohibition on taking swordfish in FMAs 1 and 9 was removed and the prohibition on taking marlin species was extended to include all NZ fisheries waters. At that time domestic commercial fishers agreed to avoid fishing certain areas to reduce conflict over recreational access to swordfish. However, since 1993 the commercial domestic fleet has grown much larger and no longer observes these area agreements.
87. In general, landings of swordfish reflect the number of hooks placed in the water for these species. The total number of hooks was stable between 1985 and 1995 but increased between 1995 and 2000 with the effort progressively levelling off. Landings of swordfish by domestic vessels have increased rapidly since 1994-95 peaking in landings of 1 014 tonnes in 2000-01. Since, landings have progressively declined to 669 tonnes during 2002-03.

88. Swordfish can be caught in most FMAs although most catches are from waters north of latitude 40º S. Most domestic landings (86%) are reported from FMA 1, FMA 2 and FMA 9.
89. Pelagic and Tuna stakeholders group undertook analysis of the distribution of broadbill swordfish catch during 1989 and 2001. From 1989-2001 most swordfish was taken along the edge of the continental shelf off the east coast of the North Island. Highest catches were reported off East Coast, Gisborne, in the Bay of Plenty, and the Poor Knights shelf. Since 1995-96 the development of the domestic tuna fishery resulted in a level of catch and an extension of the geographic range where swordfish has been caught. In the subsequent years, the fishery expanded northwards and down the central east coast of the North Island. The fishery also expanded to the northern west coast of the North Island.

90. In New Zealand waters, swordfish are primarily caught in the tuna longline fishery as a bycatch when targeting bigeye, southern bluefin tuna and to lesser extent albacore. For the domestic fleet 75% of hooks are reported as targeting bigeye, 16% as southern bluefin tuna, 7% as albacore and the remaining 2% other tunas.

91. Swordfish have occasionally been observed as a bycatch of the skipjack tuna purse seine fishery (Habib et al. 1982) and in trawl fisheries for jack mackerel (Anderson et al. 2000) and hoki (Clark et al. 2000).
92. It is known that swordfish catch rates can be increased by choice of longline gear, longline setting strategy such as setting at night and the using of lightsticks, hence there is considerable potential for swordfish catches to increase or decrease depending on the adoption of fishing practices [1].
93. Based on MFish observer data, discard rates are about 0.4% of the reported landings with most (57%) of the discarded swordfish dead upon their return to the sea.

[1] Factors affecting swordfish (Xiphias gladius) catch rate in the New Zealand tuna longline fishery Murray and Griggs.

94. The number of domestic vessels reporting landings of swordfish by year is shown in Table 4.
    

95. The numbers of vessels that catch and report landing swordfish reflect the development of an important surface longline fishery for bigeye and southern bluefin tuna since 1996-97. There is a relatively large number of vessels reporting landings of swordfish, consistent with the largely bycatch nature of the fishery. The number of vessels reporting swordfish landings decreased in 2002-03 since peaking in 2001-02. This is associated with the decline in catch for that year.

96. The recreational fishery for billfish pre-dates the development of a commercial fishery for large pelagic species by many years. This recreational fishery is dominated by striped marlin but there has always been a considerable recreational interest in swordfish.
97. Angling for swordfish involves floating baits near the surface while drifting at night further from the coast that is routinely fished by recreational vessels. Recreational swordfish fishing can therefore be an uncomfortable experience in exposed oceanic waters with the additional dangers of navigating at night. Accordingly, recreational catches to date have been relatively small (if most of the recreational catch is attributed to gamefishing, the recreational catch has averaged seven swordfish per year since 1987-88 with a maximum of 36 fish in 1992-93). Nevertheless, the recreational sector’s interests and aspirations are similar to those of commercial fishers in that it sees potential for a recreational swordfish fishery to expand.
98. Recreational fishers place considerable value on the retention of trophy-sized swordfish within areas that are of particular interest to them. Recreational fishers have expressed concern about the potential impact the current level of commercial catch of swordfish might be having on their fishery. While there are limited direct gear conflicts, spatial conflict exists between the sectors particularly in light of the current assumption that as in Australian waters large New Zealand swordfish may have long residence times (in preferred habitats within the EEZ), which make them vulnerable to over fishing [2].
99. MFish is not aware of any current customary Maori fishery for swordfish, however it is known that swordfish have been harvested in the past.
    

100. From 1991 swordfish became subject to regulations that restricted catch to bycatch only, except for those existing target fishers who had received a fishing permit in previous years. This meant swordfish could be legally landed only as bycatch of target fishing for another species.
101. No specific regulatory measures apply to the swordfish fishery with the exception that regulations apply to the operation of foreign owned vessels registered to fish within New Zealand fisheries waters. These regulations include a provision excluding the use of foreign owned tuna longline vessels in the Auckland Fisheries Management Area from 1 October to 31 May in the following year.

102. In the Pacific other fleets catch swordfish and the Japanese in particular have a long history of longlining for swordfish and other tunas. During the 1980s, two studies assessed Pacific swordfish stocks by applying equilibrium production models to Japanese data. These studies provided similar results by suggesting a MSY for Pacific swordfish to be about 20 000 tones per year (range 18 000-28 000 tonnes). These assessments suggest that the Pacific stock was under exploited until the early 1980s. More recent assessments have been inconclusive and the condition of the Pacific stock remains uncertain.
103. Stock structure, longevity and productivity of the central south stock are uncertain and little is known of the biology and ecology of swordfish in this area. However, it is often assumed that swordfish, particularly large swordfish, may have long residence times which may make them vulnerable to over fishing.
104. Since 1998, swordfish landings in New Zealand have been stable and for the most recent two years decreasing. However, there is no evidence of declines in catch per unit of effort or in the average swordfish size taken within New Zealand fisheries waters that suggests that swordfish abundance is in decline or that stock status is changing. (This conclusion is based on analysis of catches up to 2001-02. Catch rates since the fishery peaked in 2001-02 have yet to be analysed). There is some anecdotal information from recreational and commercial fishers that swordfish are not as abundant in some areas as they once were.

105. The catch composition of surface long lining suggests distinct associations between swordfish and a set of pelagic species. The main species associated with long lining include: bigeye tuna, blue shark, albacore tuna, Ray’s bream, southern bluefin tuna, porbeagle/mako shark, dealfish, moonfish, oilfish, and deepwater dogfish.
106. Sharks and marine mammals such as sperm whales, false killer whales and killer whales are known to predate swordfish. Sharks, particularly mako and blue shark, attacking swordfish hooked on longlines are a source of wastage in the fishery.
107. As mentioned, swordfish is primarily caught in the tuna longline fishery as a bycatch when targeting bigeye and southern bluefin tuna. Bigeye tuna and southern bluefin are being introduced into the QMS at the same time as swordfish. MFish has considered economic implications of setting TACCs for associated species starting at paragraph 117 below.

108. Swordfish, as high-level predators, form an important ecological relationship with their prey, and possibly with some marine mammals. The effect on the ecosystem of large-scale removals of a single species is unknown.
109. In New Zealand waters swordfish is primarily taken by surface longline. Environmental issues are common to the fishing method rather than specific to fishing for swordfish. Long lining is not considered to have any direct effects on swordfish habitats.
110. A wide range of fish species are taken as bycatch of surface longline fishing. Catches of these species vary but many of these are only rarely taken. The main fish bycatch species associated with the New Zealand surface longline fisheries are being considered for introduction into the QMS. This will provide the mechanisms for sustainability actions as required.
111. There is also a non-fish bycatch associated with the surface longline fishery. Fishing vessels sometimes capture seabirds that are chasing baited hooks, and the seabirds drown as the lines sink. Seabirds are also caught in trawl and other fisheries, but longliners are considered to be the main threat to several vulnerable albatrosses and other seabird species. The risks of seabird capture vary geographically and by species. An active programme is underway to mitigate and monitor the capture of seabirds in surface longline fisheries.
112. MFish has established standard environmental controls on line and trawl target fisheries to mitigate the impact of these fishing methods on seabirds. These include prohibitions on net sonde monitor cables and compulsory reporting of bycatch of protected species. New Zealand surface longline vessels are required to use tori lines of a specified standard. Vessels are using a variety of practices to reduce seabird bycatch including the use of artificial baits and the practice of setting longlines at night.
113. MFish and the Department of Conservation are currently evaluating submissions on a draft National Plan of Action (NPOA) for Seabirds that is expected to result in additional measures that will apply to all fishing vessels fishing for swordfish. Surface longlining is identified by the NPOA as having known interactions with seabirds. Therefore, stakeholders will need to develop an effective code of practise for this method by 2004.
     

114. Information on the New Zealand fishery (catch per unit of effort) is routinely contributed to the international status reports for the central southern Pacific swordfish stock. Factors affecting CPUE have been evaluated for the New Zealand longline fishery. Age and growth and the stock structure of New Zealand swordfish are currently being investigated.
115. Research on the interrelationships between swordfish and other elements of the aquatic environment has been identified as an area for future consideration, however, this is a complex area of study and it is unlikely to be undertaken in the foreseeable future.
116. As mentioned, obtaining reliable estimates of recreational catch for swordfish has proved difficult. Further work to estimate, and to differentiate, recreational catches and landings are required.
     
     

117. Swordfish is a medium value species that is an important component of the domestic tuna longline fishery in New Zealand. MFish considers introduction of swordfish into the QMS has economic benefits for commercial fishers by allowing fishers to fish for swordfish in a way that optimises the value of the catch.
118. However, there will be short-term impacts arising from introducing swordfish into the QMS associated with the need for individual fishers to acquire quota to reflect their current fishing operations. Swordfish landings in the criteria years for catch history were substantially smaller than they are currently.
119. Two other socio economic factors have been considered:

1. Are there any socio economic implications of the proposed TACC in comparison to recent landings of swordfish?
2. Are there any socio economic implications of setting the proposed TACC for swordfish with respect to anticipated levels of bycatch under proposed TACCs set for its main target species?

120. The proposed TACC is based on the average of the most recent years landings and therefore no direct socio-economic impact is predicted.
121. The main target species of swordfish are being introduced into the QMS at the same time as swordfish. There could be important implications for fishing for bigeye tuna or southern bluefin tuna if the proposed TACC for swordfish impacts on the ability of fishers to target species in fisheries where swordfish is taken as a bycatch.
122. To address this issue, MFish has analysed the level of bycatch recently reported for swordfish in greater detail. As mentioned, there have been changes in fishing practise that has resulted in the proportion of swordfish bycatch increasing in some target fisheries. MFish considers that the bycatch reported over the past six years provides the best point of comparison for comparing TACC options and ascertaining whether fishing for associated species might be affected.

123. Swordfish bycatch is associated with target fishing for bigeye tuna and southern bluefin tuna. The level of swordfish bycatch reported from each of the bigeye and southern bluefin tuna fisheries and the ratio of bycatch species to target species weights has been increasing over the past six years. The albacore fishery and its associated bycatch of swordfish is more stable. However, MFish does not consider that recent reported commercial swordfish landings necessarily represent a minimum level in terms of a manageable bycatch. It is known that swordfish catch rates can be increased by choice of longline gear, longline setting strategy such as setting at night and the using of lightsticks, hence there is considerable potential for swordfish catches to increase or decrease depending on the adoption of fishing practices. In a largely unrestrained management environment it is to be expected that some fishers have attempted to optimise the level of bycatch of swordfish as suggested by the data in the above table.
124. Fishery characteristics (particularly the relationship between swordfish and other target fisheries) indicate that the TACC proposed will provide a manageable level of bycatch without detrimentally affecting the targeting of associated fisheries. In some circumstances changes in fishing practices might be necessary. As discussed, bycatch levels of swordfish can be substantially reduced with a concomitant reduction in the risk of any economic impact associated with constraints on fishing imposed by any of the current proposals.
125. Though not a common catch of recreational fishers swordfish is highly prized when caught. Maori probably does not consider swordfish to be a species of particular importance.