© Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia Full citation Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia: Volume 1 - Bony and Cartilaginous Fishes. Report for the South Australian Working Group for Marine Species of Conservation Concern. J. Baker (consultant); Science and Conservation Division, and Coast and Marine Conservation branches of S.A. Department for Environment and Heritage (DEH); Marine and Coastal Community Network of S.A. (MCCN), and Threatened Species Network (TSN). Web version published by Reef Watch, South Australia.

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Hapuku / Hapuka / Bass Grouper

Family Name:	Polyprionidae
Scientific Name:	Polyprion oxygeneios (Forster, 1801)
Recommended Status in S.A:	Near Threatened, possibly Vulnerable A2(d) (S.A. State waters, and Commonwealth waters)
Rationale:  Hapuku is included here because (i) it is a large, slow growing, long-lived species (to about 60 years) with low natural mortality, high age at maturity, and low reproductive output; and these characteristics can increase its vulnerability to population decline; (ii) it is, in some areas, strongly site-associated with reefs, sea mounts and other benthic structures, and highly vulnerable to capture using a variety of gear types; (iii) small Hapuku form seasonal aggregations, that are vulnerable to capture by trawl and non-trawl methods; (iv) targeting of spawning aggregations (as occurs in New Zealand) or targeting of aggregations of  small Hapuku that have not had opportunity to spawn, may be an unsustainable fishing practice; (v) Hapuku are thought to be naturally less abundant than many other species targetted in Commonwealth-managed line fisheries, and there is concern that Hapuku may be preferentially targetted due to its high value; (vi) serial exploitation of stocks across the range may have occurred, without adequate research and management into the sustainability of fishing this species; (vii) in southern Australia, the species is taken in numerous fisheries (Commonwealth- and State-managed). During the 1990s and early 2000s, when this species was being actively exploited by numerous fisheries, there was no stock assessment for Hapuku in Australia. To date (2007), there are still inadequate controls over the catch of this species in individual fisheries, and over the total catch from combined fisheries, even though Hapuku has been classified as a “high risk” species in the South East Trawl Fishery, and a “medium risk” species in the Great Australian Bight Trawl Fishery; (viii) in deeper waters off eastern Australia, experimental fishing during the early 2000s has targetted recently discovered stocks; (vi) the species is reported to have a very low resilience to exploitation, in terms of minimum population doubling time; (ix) as is the case with other Polyprion species, serial depletion of stocks is hard to reverse and it may take many years for stocks to recover, due to the long-lived nature, slow growth, and high age at maturity of this species, and the fact that there may be a substantial lag between the reproductive output declining due to over-fishing, and the manifestation of that situation in decreasing catches.

Page Contents

Current Conservation Status

No listings known for Polyprion oxygeneios.
It is noted that the closely related species P. americanus (Bass, Bass Groper or Wreckfish) is listed as Data Deficient in the IUCN Red List 2008 (IUCN, 2009).

Distribution

General

Hapuku occurs in the southern hemisphere, including southern Australia, New Zealand, South Africa, South America (e.g. Chile), Tristan da Cunha, the Juan Fernández islands (Sepúlveda and Pequeño, 1985, cited in Froese and Pauly, 2007; Paxton et al., 1989; May and Maxwell, 1986; Gomon, in Gomon et al., 1994). There are also records from other areas including the Foundation Seamounts (central South Pacific) (Roberts, 2003), and a recent record from the south-west Atlantic (at Rio Grande do Sul) which represents a northern range extension in that region (Barreiros et al., 2004).
Hapuku are distributed widely around New Zealand (Francis, 1996; Anonymous, 2004). Polyprion oxygeneios occurs in shelf and slope waters of the New Zealand mainland and offshore islands, from the Three Kings Is. and Kermadec Is. to the Snares Shelf and Auckland Is. (New Zealand Ministry of Fisheries, 2004f). The distribution includes the Chatham Rise, but not the Campbell Plateau. Presence at the Challenger Plateau is uncertain (National Institute of Water and Atmospheric Research Ltd, 2004). The North Island and south-east South Island / Cook Strait areas may support separate stocks (Beentjes and Francis, 1999).

Southern Australia

In Australia, Hapuku is found in southern Western Australia (Hutchins and Thompson, 1983), South Australia, Victoria, New South Wales and Tasmania (Kailola et al., 1993; Gomon et al., 1994).

South Australia

In South Australia, examples of locations where Hapuku occur include deeper waters of the western, central and eastern Great Australian Bight (CSIRO Marine Research records, 1966-1970, cited in CSIRO, 2007); deeper waters south of Kangaroo Island, and deeper waters off the south-east coast of S.A. (SARDI data, unpublished).
The historical records section of CSIRO Marine Research houses approximately 161 records of P. oxygeneios from South Australian waters (State- and Commonwealth-managed waters), and almost all of these were recorded between 1965 and 1975. Most records housed by CSIRO are trawl catches in the Great Australian Bight.

Habitat

Hapuku are found in temperate areas, mainly in deeper waters of the central continental shelf (about 100m) to the shelf edge and upper slope (Gomon, in Gomon et al., 1994). Adult Hapuku are demersal, generally occurring over reef / rough bottom, and they tend to remain in discrete rocky areas (e.g. around rocky outcrops) (Gomon et al., 2008). They are also found over soft bottom (uncited reference, in AFMA, 2002a), and in canyon areas of the continental slope (Yearsley et al., 1999, cited by Bruce et al., 2002).
The upper depth limit has been recorded as shallow as 50m (Gomon et al., 1994; National Institute of Water and Atmospheric Research Ltd, 2004). The lower depth limit may be about 640m (CSIRO et al., 2001) or as deep as 854m (Barreiros et al., 2004, cited in Froese and Pauly, 2008). In southern Australia, the species is normally found in mid and outer continental shelf and upper slope waters (100m - 400m). In New Zealand, Hapuku and occupy a wide depth and habitat range, from shallow rocky reefs and pinnacles, to the open seabed at 400m or deeper (Anonymous, 2004; N.Z. Ministry of Fisheries, 2006). The species is reported to be most common over or near rocky areas from ~ 125m to ~ 250m.
The smallest juveniles are virtually unknown, but are mottled, epi-pelagic or surface-dwelling, perhaps schooling in association with drifting vegetation (New Zealand Ministry of Fisheries, 2004f, 2006). (see also section on Migration and Aggregation).

Notes on the Biology

Age and Growth

The species grows to a maximum length of about 1.5m (Grant, 1987; Gomon, in Gomon et al., 1994) or 1.8m (Anonymous, 2004; DPIF, Queensland, 2006), but individuals in the range 80cm – 120cm are more common.
Maximum weight is around 70kg (Gomon, in Gomon et al., 1994) or 100kg (Robins et al., 1991, cited in Froese and Pauly, 2008; Anonymous, 2004), but individuals in the range 3kg – 20kg are more common.
The maximum reported age is 50 – 60+ years (Francis et al., 1999; Paul, 2002), and the species is likely to have a low natural mortality rate (e.g. 0.1) (Francis et al., 1999, cited by New Zealand Ministry of Fisheries, 2006).
Hapuku is a slow growing species (Anonymous, 2004).

Diet

Generally, Hapuku feed on a variety of fish (including both pelagic and bottom species), and benthic invertebrates.
In New Zealand, Hapuku are reported to feed on Red Cod Pseudophycis bachus, Blue Cod Parapercis colias, Jackass Morwong Nemadactylus macropterus, Hoki Macruronus novaezelandiae, and calamari (New Zealand Ministry of Fisheries, 2004f). 
A study in Chile showed that Hapuku feed on bony fishes (such as pilchards, grenadiers, slimeheads, saury, sea basses, damselfishes, barracouta, redbait, morid cods, morwongs, horse mackerel and conger eels), lobsters and stomatopods (Rojas et al., 1985, cited in Froese and Pauly, 2008).

Migration / Aggregation

The juveniles are thought to be pelagic, in surface waters well offshore, often in association with flotsam (Roberts, 1996, cited by Bruce et al., 2002). Juveniles switch to a demersal habitat at about 50cm total length (age approximately 3 – 4 years) (Francis et al., 1999, cited by Bruce et al., 2002).
In New Zealand, Hapuku move seasonally in schools of several to over 100 fish (Anonymous, 2004). Northern schools move into deeper water during summer months, while in colder southern waters, Hapuku spend the summer in shallow coastal waters, and move into deeper water in winter (Anonymous, 2004).
Although Hapuku in New Zealand are often taken around reef pinnacles, sea mounts and other structures, trawlers sometimes the species on flat and clear seafloor. According to the N.Z. ministry of Fisheries (2006), it is not known whether this represents their normal habitat, whether they are dispersing by travelling from one rough ground to another, or whether they are on a purposeful spawning migration.
A study in New Zealand (Beentjes and Francis, 1999) showed that some Hapuku can remain associated with an area for long periods (years), and others can migrate over considerable distances (e.g. 2 of 1623 tagged fish moved 1,389km over 10 years). Tagging of mostly immature fish in Cook Strait has shown a high level of local returns, but about 5% of these fish have moved up to 160 km north and south (New Zealand Ministry of Fisheries, 2006). In contrast to Hapuku from the South Island and Cook Strait, tagged Hapuku from the Poor Knight Islands showed very limited movements. Although small, immature Hapuku migrate as well as adults (i.e. some immature Hapuku travelled several hundred kilometres, during the N.Z. study), the results suggested that maturation and spawning stimulate migration (Beentjes and Francis, 1999).

Reproduction

A study in New Zealand showed that age at maturity is around 10 years to 13 years, for both males and females, equivalent to about 85cm (Francis et al., 1999; New Zealand Ministry of Fisheries, 2004f).
In New Zealand populations, Hapuku in the Cook Strait region mature over a wide size range, with 50% maturity at 80–85 cm total length (TL) for males and 85–90 cm TL for females (Francis et al., 1999; Paul, 2002d, cited by New Zealand Ministry of Fisheries, 2004f).
A study of populations at the Juan Fernández islands (South America) reported a size at maturity of approximately 88cm TL for females, and 92cm TL for males (Flores and Rojas, 1985, cited in Froese and Pauly, 2007).
Studies have shown that P. oxygeneios spawns between June and August in New Zealand, and between July and September in South America (Juan Fernández islands) (New Zealand Ministry of Fisheries, 2004f; Flores and Rojas, 1985, cited in Froese and Pauly, 2007).
In New Zealand, there is some evidence for spawning to occur earlier in the season in the northern area than in the south, but running ripe fish are seldom caught, and spawning grounds are unknown (New Zealand Ministry of Fisheries, 2004f).
There appears to be no information on spawning of this species in Australian waters (Bruce et al., 2002).

Other Information

Hapuku are preyed upon by sperm whales (Annala, 1994), but probably not heavily or selectively (New Zealand Ministry of Fisheries, 2004f, 2006).
Polyprion oxygeneios are also attacked by cookie-cutter sharks (Isistius sp.) (Dalebout et al., 2004).

Fisheries Information

Southern Australia - Commercial

Hapuku is a commercial food fish, considered to be of excellent eating quality (Gomon et al., 1994), and of “very high value” (AFMA, 2002a). The official marketing name is “Hapuku” (Seafood Services Australia, 2003).
According to Bromhead and Bolton (2005), the species is caught (mostly as a retained by-product) in 10 different Commonwealth-managed fisheries, including the Coral Sea Fishery (at the edge of the geographic range in eastern Australia), East Coast Deepwater Trawl Fishery, Eastern Tuna and Billfish Fishery, Gillnet, Hook and Trap Fishery (in which it is a target species), Great Australian Bight Trawl Fishery, Norfolk Island Offshore Demersal Finfish Fishery, South East Trawl Fishery, Western Deepwater Trawl Fishery, High Seas Trawl Fishery (uncertain whether it is a by-product), and High Seas Non-trawl Fishery (target species).
Total catches of Hapuku in Australian waters during the 1990s are listed below, according to statistics from Bureau of Rural Sciences’ National Fisheries Production Database (NFPD). The P. oxygeneios catch comprises a Commonwealth component, and components from Victoria, NSW, S.A. and W.A. The South Australian component of the total catch of P. oxygeneios is also listed in a separate table, towards the end of this section. The combined P. oxygeneios and P. americanus catch is based mainly on records from NSW (where the two were combined in records, prior to 1998 - Baelde, 1999), with a minor component from Commonwealth waters during 1996 – 1999 (BRS, 2004a). According to McLeay et al. (2002), the total Australian catch of Hapuku in 2000/01 was 74t, with 32t of this (~ 43%) being taken by line fishing (Table 1).

Table 1 Hapuku: Total reported catch in Australian waters
Year	Combined Polyprion americanus & Polyprion oxygeneios Catch (t)	Polyprion oxygeneios Catch (t)
1990/91	> 59	59
1991/92	63	38
1992/93	40	29
1993/94	53	27
1994/95	26	17
1995/96	71	16
1996/97	106	29
1997/98	165	6
1998/99	131	7
(from BRS, 2004a)

Until the late 1990s, the species was taken mainly by commercial fisheries in New South Wales, and catches are shown in the table above, which lists catch statistics for Hapuku in Australian waters. The closely related P. americanus was included in N.S.W. catch statistics until 1998. During the mid 1980s, combined catches of Hapuku and Bass Grouper ranged from 30t to 40t, increased to 50t – 70t during the early 1990s, and subsequently decreased to about 30t (Bruce et al., 2002). The Marine Parks Authority (2001) reported that during 1996/97 and 1997/98, the quantities of Hapuku taken by fisheries in N.S.W. were 25.8 tonnes and 8.3t respectively, which are close to estimates recorded by BRS (see above). When separated from the Bass catch statistics in 1998, the Hapuku catch was recorded as 6t (Baelde, 1999, cited by Bruce et al., 2002). The species is caught mainly by lines in deeper water, as part of the Ocean Trap and Line fishery. According to New South Wales DPI (2004), Hapuku also forms a very small part of the trawl bycatch (< 1%) in the N.S.W. Ocean Trawl Fishery.
The total trawl catch in Australian waters ranged from 3t to 9t between 1986 and 1994, and increased from 18t to 26t from 1995 to 1998 (Baelde, 1999, cited by Bruce et al., 2002), with the increase coming from offshore seamount fishing (Bruce et al., 2002; National Oceans Office, 2002).
Hapuku is taken in the Commonwealth-managed southern and eastern scalefish and shark fisheries (SESSF) (AFMA, 2002a). Hapuku (Polyprion oxygeneios) is a significant (and highly valued) by-product species in the Commonwealth’s South East Non-Trawl Fishery (SENTF) for Blue-eye Trevalla, which is now a part of the Gillnet, Hook and Trap Fishery (GHAT) (Webb et al., 2004). In this fishery, Hapuku are taken mainly off Tasmania, by drop-line (Gomon et al., 1994; Smith and Wayte, 2001; Larcombe et al., 2002), and Hapuku is one of the two main non-quota species taken by drop-liners in the non-trawl sector (Webb et al., 2004). The species is also taken by bottom longlines (Larcombe et al., 2002, cited by Butler et al., 2002b), as well as trawls and gillnets (e.g. AFMA, 2002a; National Oceans Office, 2002; Webb et al., 2004). Although Hapuku are taken down to around 400m, most effort in the SENTF is concentrated on the edge of the continental shelf, particularly over bathymetric features such as canyons and cliffs (Larcombe et al., 2002). Hapuku is one of the 3 by-product species that together make up about 8% of the catch in the SENTF (Bruce et al., 2002). In the eastern Great Australian Bight, Hapuku are taken using demersal long-line and drop-line (Ward et al., 2003). The species is also taken off eastern Tasmania, using automatic long-line (e.g. Buxton et al., 2006). Fishers’ logbooks recorded a catch of about 37t from the SENTF in 2000/01 (AFMA, 2002a), and Webb et al. (2004) reported that about 30t per annum is the current annual catch by the scalefish hook sub-fishery of the GHAT.
The species is also a component of the retained catch in otter trawl sub-fishery of the South East Trawl Fishery (SETF) (Wayte et al., 2004). Fishers’ logbooks recorded a catch of about 34.5t of Hapuka from the SETF in 2000/01 (AFMA, 2002a), and Webb et al. (2004) reported that about 30t per annum are taken by the SETF. In 2001, the trawl catch of the combined SETF and Great Australian Bight Trawl Fishery (see below), was listed as 27.4t (AFMA, 2002a).
Hapuku are also taken in the Commonwealth’s Gillnet, Hook and Trap (GHAT) fishery (i.e. the former Southern Shark Fishery), using gillnets. In the fishery, gillnets are set in relatively shallow, continental shelf waters, and the bulk of fishing is concentrated in Bass Strait, and in an area west of Kangaroo Island (Larcombe et al., 2002). Butler et al. (2002) listed Hapuka as one of the 6 major species from the gillnet fishery in south eastern Australian waters, with the other 5 being sharks. Webb et al. (2004) also listed Hapuku as a bycatch of the hook sector of the GHAT. The species is also taken in the scalefish demersal long-line sub-sector, scalefish automatic long-line sub-sector, scalefish drop-line sector, and the scalefish trap sector (AFMA, 2002a; Webb et al., 2004). In 2001, the Gillnet, Hook and Trap Fishery catch was reported to be 23 tonnes (AFMA, 2002a), and during the years 2002 – 2006, the average annual catch of Hapuku was more than 50t (AFMA, 2007b).
Hapuku have more recently been targeted by drop-line off the Norfolk Rise, off eastern Australia (Bruce et al., 2002). In an AFMA-instigated exploratory fishing program over 3 years (2000-03) in the vicinity of the Wanganella Bank south of Norfolk I., Hapuku was one of 3 species that dominated the catches by hook (Caton and McLoughlin, 2005).
Polyprion oxygeneios is listed as a significant species in the Queensland Deepwater Finfish Fishery (DFF), which operates at the northern end of the range of Hapuku (Sumpton and Ryan, 2004). In the DFF, fish are taken in waters deeper than 200m, using multiple-hook fishing apparatus, which allows up to 300 hooks to be deployed using drop lines or bottom set long lines (trot lines) (Sumpton and Ryan, 2004).
Hapuku is a minor component of the catch in the Great Australian Bight Trawl Fishery. Reported catches in recent years are shown below (Table 2).

Table 2 Hapuku: Reported Commercial Catch in the GABTF
Year	Catch (t)
1995	3
1996	1
1997	5
1998	10
1999	14
2000	4
2001	3
2002	2
Lynch and Garvey (2003)

During bycatch sampling in the GABTF in 2000 and 2001, Hapuku were observed in 17 of the 209 trawl shots; all Hapuku that were caught were retained, and the average quantity retained was 25kg per trawl shot (Brown and Knuckey, 2002).
In Tasmania, Hapuka is one of the species listed in the general (commercial) fishery (Lyle and Jordan, 1999). In Tasmania, Hapuku were previously included with Blue-Eye Trevalla catch statistics (Baelde, 1999, cited by Bruce et al., 2002).  In that State, Blue-eye Trevalla have traditionally been an important offshore species in Tasmanian commercial drop-line fishing on the continental slope; however, under an Offshore Constitutional Settlement (OCS) agreement during the late 1990s, the Commonwealth has assumed management responsibility for the species, along with others such as Hapuku (Lyle and Jordan, 1999).  Reported catches of Hapuku in Tasmania are shown below (Figure 1).

Figure 1 Hapuku: Reported commercial catch from Tasmania

(from Lyle and Jordan, 1999)

In W.A., Hapuku are caught mainly on the edge of the continental shelf, along the south coast. During the 1990s, the total commercial “wetline” fishery catch of Hapuku in W.A. was reported to range between 9t and 13 t per year from 1991/92 to 1994/95, and from 19t to 22t per annum from 1995/96 to 1998/99 (Crowe et al., 1999) Catch of Hapuku in the south-western area (i.e. mainly between 33°S to 115°30’E) reportedly increased from 0.4t in 1991, to 7.8t in 1997-98 (Crowe et al., 1999), and continued to increase during the early to mid 2000s. In 1999-2000, 2000-01, 2001-02, and 2002-03, the Hapuku catches from the south-western area / South Coast Bioregion of the State’s “wetline” fishery were approximately 7t, 21t, 20t, and 22t respectively (W.A. Fisheries Research Division, 2003, 2004, 2005).
Hapuku is one of the minor by-product species taken in Western Australia’s Joint Authority Southern Demersal Gillnet and Demersal Longline Fishery (JASDGDLF), a fishery that extends from Bunbury in southern W.A., across to the S.A. / W.A. border, and is managed by the Commonwealth Government and W.A. Fisheries. The fishery mainly targets several shark species; however a number of scalefish are also caught as by-product. In a bycatch study of demersal gillnet and demersal long-line fishers between 1994 and June 1999, Hapuku made up 1.9% (= 0.4 tonne) of the bony fish bycatch in region 2 (southern coast of W.A., between longitudes 119°E and 124°E) (McCauley and Simpfendorfer, 2003). During bycatch surveys from 1994 to 1999, the annual gillnet catch of Hapuku ranged between 152 (in 1998-99), and 2,101 specimens (in 1995-96), with the majority of the catches coming from region 2 (see above), and region 3 (between longitudes 116°E and 119°E) (McCauley and Simpfendorfer, 2003). In 1999/2000, Hapuku constituted 23.5% of the scalefish catch (and scalefish comprised 13% of the total catch) in Zone 2 of the JASDGDLF (Fisheries Research Division, 2001). In W.A., Hapuku is part of the bycatch in the Western Trawl Fishery. Between 1993 and 2004, approximately 1,326 specimens were recorded in a logbook program, with none recorded in some years, and up to 344 recorded in 2002-04 (AFMA, 2004f).
The total annual yields of Hapuku from all fisheries in W.A. are provided (Table 3).

Table 3 Reported catches of Hapuku from W.A. waters, 1994-95 to 2004-05
Year	Live weight (kg)	Landed weight (kg)
1994/95	10,410	10,016
1995/96	22,981	21,161
1996/97	22,285	21,257
1997/98	21,738	20,366
1998/99	10,622	10,342
1999/00	13,855	13,590
2000/01	24,140	24,042
2001/02	25,448	25,377
2002/03	28,820	28,493
2003/04	33,530	32,732
2004/05	42,303	42,276

(W.A. Fisheries Research Services Division statistics 1994-2001, extracted from W.A. Fisheries website, 2003, and W.A. State of the Fisheries reports, 2000/2001 - 2005/2006)

South Australia - Commercial

In S.A., Hapuku are caught in small tonnages, previously recorded as part of the Marine Scalefish Fishery. During the mid to late 1990s, catches over 1t per annum were taken in several of the 1-degree fishing blocks, including southern Kangaroo Island (e.g. 1.8t, in one year); deeper, Commonwealth-managed waters west of Beachport in the South-East (e.g. 3t, in one year); and deeper coastal waters of the lower south-east, between Beachport and Port MacDonnell (e.g. 8.6t and 1.2t in two consecutive years). During that period, minor catches of less than 1t per annum, were made in several other areas (e.g. upper South-East; south-western and southern Kangaroo Island; south-eastern end of the Great Australian Bight). Drop-line fishing in deeper (including shelf-edge waters) of the South-East (100m - 900m) yields species such as Hapuku (Jones, SARDI pers. comm. 1996, cited by Edyvane et al., 1996). The catch of Hapuku from S.A. during the 1990s, according to the National Fisheries Production database (BRS, 2004a) and SARDI statistics (Knight et al., 2002) is shown in the table below. An Offshore Constitutional Settlement agreement during the late 1990s gave the Commonwealth management responsibility for the species, and hence more recent catches (marked *) from deeper waters off S.A. do not appear in the table below (Table 4), and are not cited in S.A. fisheries statistics reports (e.g. Knight et al., 2005, 2007):

Table 4 Hapuku (P. oxygeneios): Total reported catch from South Australian waters
Year	P. oxygeneios catch (t)
1990/91	27
1991/92	26
1992/93	12
1993/94	15
1994/95	6
1995/96	15
1996/97	9
1997/98	2 or 4
* 1998/99	< 1
* 1999/00	0
* 2000/01	-
(from BRS, 2004a, and Knight et al., 2002)

Southern Australia - Recreational

In all southern States, some recreational fishers and charter boat operators take Hapuku.
The species is listed as being taken by charter boat fishers in New South Wales (N.S.W. Department of Primary Industries, 2005f).
Recreational fishers in WA (e.g. Rottnest Island, and other locations) regularly target Hapuku and Bass Groper P. americanus in deep water (some fishers call both species Hapuku) (B. Hutchins, W.A. Museum, pers. comm., 2007).
Some fishing clubs keep records of the maximum sizes caught (e.g. N.S.W.). The record size of a specimen taken by angling is 32.6kg (New South Wales Fishing Clubs Association record, 1990;  Hutchins and Swainston, 2001).
The species is taken by anglers in Tasmania (Lyle and Campbell, 1999). Small Hapuku are occasionally netted in coastal waters around Tasmania (Hutchins and Swainston, 1986, 2001).
The National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) recorded low numbers of Hapuku taken by recreational fishers. During the survey time period (May 2000 to April 2001), the survey reported that 85 and 257 Hapuku specimens were caught and kept by recreational fishers in South Australia and Tasmania respectively.

South Australia - Recreational

The species is not taken in large numbers by recreational fishers in South Australia, due to the depth at which populations occur. Hapuku are taken seasonally, during autumn and early winter, in areas such as the lower South-East (e.g. offshore from Port MacDonnell, close to the edge of the continental shelf) (Sweeney, 1996b).

New Zealand - Commercial

The species is caught commercially in large numbers in New Zealand, as part of a “groper” fishery, in which both Polyprion oxygeneios (Hapuku) and P. americanus (Bass, Bass Groper, or Wreckfish) are taken in different proportions, according to region, depth, fishing method and season (New Zealand Ministry of Fisheries, 2004f). The proportion of the two species in the catch has changed over time. Reported catches generally do not distinguish between species, and published data combine them. In earlier years, Blue-eye Trevalla (Hyperoglyphe antarctica) was sometimes also combined with Hapuku and Bass catches. The main fishery comprises a number of domestic fishers working small to medium sized vessels – using long-lines, set nets and trawls, at a variety of depths (according to method) out to 500m (Paul, 2002a, cited by New Zealand Ministry of Fisheries, 2004f). The Hapuku fishery is nationwide, with the largest catches coming from Northland, East Cape, Hawkes Bay and Cook Strait/Canterbury (Anonymous, 2004). Main fishing areas also include the deep canyons off the East Coast of the North Island, Cook Strait, off Kaikoura, and off the West Coast of the South Island. Hapuku are caught mainly by long-line and hand-line, though occasionally by trawl, gill-nets (since the 1970s), cod pots, and recently by set nets (New Zealand Ministry of Fisheries, 2004f; Weeber and Szabo, 2005).
Hapuku are about 50cm long and 3-4 years old (Francis et al., 1999; Baelde, 1999, cited by Bruce et al., 2000) or 5 years old (Paul, 2002a) when they are recruited to the fishery. The size range of commercially caught Hapuku is 50–140 cm TL, with a broad mode between 70 and 100 cm TL (N.Z. Ministry of Fisheries, 2006). There appear to be some regional differences in the size structure of populations. Trawl-caught Hapuku on the Stewart-Snares Shelf are mainly 50–80 cm, modal length 60 cm, and therefore juveniles. Trawl-caught Hapuku on the Chatham Rise are slightly larger, 50–100 cm, modal length 70 cm. Hapuku on the shelf around the islands are caught at a mode of  60–75 cm; most of these fish are also juveniles. These offshore regions may be important nursery areas (N.Z. Ministry of Fisheries, 2006). A history of the Hapuku and Bass fishery in New Zealand, derived mainly from fishery status reports (N.Z. Ministry of Fisheries, 2004f, 2006) is provided as follows: Hapuku have been an important commercial species in the inshore fishery, with catches mostly between 1000 and 2000 tonnes per annum recorded since the 1930s. The first recorded landings of about 1500t in 1936 were generally typical of the range of catches (1000t–2000 t) from then until 1978. After a decrease during the war years when effort was restricted, landings in the total fishery slowly declined from almost 2000t in 1949 to about 1300t in the mid 1970s. From the mid-1970s there was a significant rise in catch, which increased sharply to 2300t - 2700 t between 1980 and 1984, and TACC limits were imposed (Anonymous, 2004). Over 90% of total catches in the early years (to 1950) were taken by long line. Trawl catches rose from 5–10% during this period to 20–30% by the late 1970s. A set net fishery developed in the late 1970s and early 1980s, mainly at Kaikoura, taking 14% in 1983 and then subsequently declining. From 1950 to the mid 1980s, line-fishing took 70–80% of the catch. After the introduction of the Quota Management System in 1985-86, the proportion of the catch taken by lines appeared to drop (N.Z. Ministry of Fisheries, 2004f). The Cook Strait region has always supported the main fishery, followed by the Canterbury Bight; both showed the same slow decline from 1949 to 1986. Northland, Bay of Plenty and Hawke Bay fisheries developed at different rates during the 1960s and 1970s. In most other areas, the fishery has been small and/or variable (N.Z. Ministry of Fisheries, 2004f). The peak catch from New Zealand, was about 2,698 tonnes, in 1983-84 (Weeber and Szabo, 2005). In 1990/91 the national catch reported to be 1062.5 tonnes (Anonymous, 2004), and during the 1990s, the annual total allowable catch (TAC) of Hapuku was around 2,100t.  From 20001-02 to 2006-07, the TAC was 2,182t, divided amongst 8 fishing zones (N.Z. Ministry of Fisheries, 2006). The reported landings in 2001-02 were 1,514 tonnes (Weeber and Szabo, 2005).
The species is also listed as a major by-product species of the long-line fishery for Ling (Genypterus blacodes) (Weeber and Szabo, 2005).
Hapuku is also taken in international waters off New Zealand, in the High Seas Fishery (N.Z. Ministry of Fisheries web site, 2006). It is also a by-catch of tuna long-lining in the Western and Central Pacific region (Kirby, 2006).
Hapuku is considered to have potential as an aquaculture species in New Zealand (Jeffs, 2003).

New Zealand – Recreational

Hapuku is a game fish taken by anglers who fish deeper waters. The species is very popular with recreational anglers and considered to be “excellent eating”. Hapuku are taken by charter boat fishers in New Zealand, particularly charters that specialise in deeper water “bottom fishing”. Hapuku are considered to be the “mainstay” of bottom fishing around the East Cape.
In New Zealand, Hapuka is promoted as a species for angling and spearfishing (e.g. Bakker, 2004), and some clubs and associations keep records of the maximum sizes caught. Hapuku is promoted to spear fishers as a species “which can still be captured in remote locations” (Smith, 2000; International Freediving and Spearfishing News, undated).

Vulnerable Population Characteristics, and Threatening Processes

Hapuku have characteristics that increase their vulnerability to population decline, including slow growth, delayed reproduction (age at maturity 10 - 13 years), low natural mortality rate, low reproductive output, and long life span (to ~ 60 years) (Francis et al., 1999; Annala et al., 2003). As with the closely related species P. americanus, serial exploitation of stocks, when research and management measures are inadequate, leads to population declines that are hard to reverse, due to the long-lived, slow-growing nature of the fish, and the fact that there may be a substantial lag effect between reproductive output declining due to over-fishing, and the manifestation in decreased catches (e.g. Sedberry, 1999, cited in IUCN, 2006).
Adult Hapuku associate with reefs, sea mounts and other benthic structures, which increases their vulnerability to capture. For example, the New Zealand Ministry of Fisheries (2006) reported that “it is known that good fishing grounds, particularly pinnacles and reefs or ledges, can be quickly fished out and take some time to recover, suggesting a high level of residency (except, perhaps, for the spawning season)”.
Hapuku are thought to be naturally less abundant than other species targetted in Commonwealth-managed line fisheries, and there is concern that Hapuku may be preferentially targetted due to its high value (Webb et al., 2004).
Small Hapuku (2 – 5kg) form seasonal aggregations, that are vulnerable to capture by trawl and non-trawl methods (Bruce et al., 2002).
The species is reported to have a very low resilience to exploitation, in terms of minimum population doubling time (based on population characteristics such as delayed maturity and long life span) (Froese and Pauly, 2007).
In southern Australia, the species is taken in numerous fisheries in Commonwealth-managed waters, as well as State-based fisheries. During the 1990s and early 2000s, when this species was being actively exploited by numerous fisheries, there was no stock assessment for Hapuku in Australia (Bruce et al., 2002; National Oceans Office, 2002). To date, there are still inadequate controls over the catch of this species in individual fisheries, and over the total catch from combined fisheries.
Exploratory fishing in offshore areas (e.g. off Australian external territories) has recently been undertaken, but it is not known if stocks of comparatively slow-growing seamount species (such as Hapuku) can support a commercially viable sustainable fishery within the EEZ (Caton and McLoughlin, 2005).
In a draft ecological risk assessment for the South East Trawl fishery, Hapuka was classified as being at “high risk” of population impacts from capture in the otter trawl sub-fishery of the SETF (Wayte et al., 2004). In a similar assessment for the Great Australian Bight Trawl Fishery, Hapuka was listed as being at “medium risk” of population impacts from capture in that fishery (Daley et al., 2006).
In W.A., the species is reported to be at “moderate biological risk” due to low abundance, long life span, and correspondingly high age at reproduction. It is considered to have “low to moderate vulnerability to fishing and environmental factors”, and to be at “moderate risk” of over-exploitation”, due to high size at maturity (Department of Fisheries, Western Australia, 2004d). Overall, it is currently listed in W.A. as a Category 1 “highest risk” species, with corresponding size limits for commercial and recreational fishers (see below).
In New Zealand, one of the Waitangi Tribunal Reports (Anonymous, 2004) stated that Hapuku populations can be “easily fished out and not recover for many years, if at all”. In New Zealand, although the species is fished all year round, landings peak in mid winter during the spawning season (June-August). The catching of aggregations before they have an opportunity to spawn in the season, could be considered a threatening process. The N.Z. Ministry of Fisheries (2003, cited by Weeber and Szabo, 2005) stated that “current total allowable commercial catches are larger than the maximum current yield estimates, and it is not known if they are sustainable or at levels that will allow the stocks to move towards a size that will support the maximum sustainable yield.”(Ministry of Fisheries, 2003, p. 227). In an ecological risk assessment for New Zealand fisheries, Hapuku was listed as category “E” (= Red), a species to be avoided (Weeber and Szabo, 2005), due to it biological characteristics (long life span, and slow growth); inadequate knowledge of population sizes and sustainable yields (including unknown sustainability of the current catch limits, and uncertain status of the stock); lack of species-specific stock assessment; lack of a species-specific management plan (Polyprion oxygeneios and P. americanus are combined); serial depletion of older individuals (due to line fishing); virtual disappearance of large Hapuku from SCUBA-diveable depths; and the decline in reported landings in recent years (Weeber and Szabo, 2005). Other concerns with the fisheries for Hapuku in New Zealand include potential depletion of a food source for sperm whales (although it is noted here that sperm whales eat a variety of different foods); bycatch of deepwater sharks (such as Seal Shark), and also the effect of trawling (including bycatch of benthic fishes, and reduced diversity and abundance of fragile invertebrate species such as cold water corals, sponges and bryozoans) (Weeber and Szabo, 2005).

Management Requirements

There are few management measures in place for Hapuku (Webb et al., 2004). 
Biological reference points / performance measures are required for Commonwealth-managed fisheries that catch this species. Such measures are reported to be under development (AFMA, 2002a).
As at January 2007, the species was not yet under a quota system in Commonwealth-managed fisheries, although in some fisheries, there are quotas for the target species associated with Hapuku catches (e.g. Blue-eye Trevalla, in the SENTF / Gillnet, Hook and Trap Fishery). If practicable, a global quota (divided amongst fisheries) for Hapuku could serve to improve the unregulated nature of catches, and to help protect Hapuku from over-exploitation in Australian waters.  Regardless of whether or not a global quota is deemed suitable, this species continues to require the urgent attention of fisheries management across the range.
In both State- and Commonwealth-managed fisheries, Hapuku catches should be rigorously documented and monitored.

Management Notes

For Commonwealth fisheries in south-eastern Australia, the South East Fishery Assessment Group monitors annual catches of Hapuku, and one of the working groups (mainly for Blue-eye Trevalla) has recently began stock assessment work on Hapuku (AFMA, 2002a).
In 2005, the board of the Great Australian Bight (fishery) Management Advisory Committee considered establishing ‘upper limit’ triggers for Hapuka catches in WA and SA (AFMA, 2005e).
In the charter boat fishery in S.A., there are passenger catch limits (2 Hapuku) and boat / trip limits (PIRSA, 2005b).
In W.A., there are size limits, bag limits (2 per day) and possession limits for recreational fishers catching Hapuku (Department of Fisheries, Western Australia, 2004d), although it is noted that Hapuku, being a deeper water species, are not commonly targeted by recreational fishers. For both commercial and recreational fishing, there is a prohibition on the take of Hapuku larger than 1m long, or over 30kg (Department of Fisheries, W.A., 2006b). In 2005, quotas were being considered for the commercial “wetline” fishery in W.A., partly to control increasing fishing effort on species for which little biological information exists.

Research Requirements and Notes

Very little is known about Hapuku in Australian waters (National Oceans Office, 2002). Stock structure is unknown (AFMA, 2002a). Research into spawning of this species in Australian waters is required. There appears to be little knowledge of age and size at maturity, spawning times and locations, fecundity, and annual recruitment strength in Australian waters. There has been very little aging data available on this species, but there has been some otolith sample aging in recent years from samples collected by the ISMP observer program. In 2005, 143 samples were aged, and 210 in 2006, most of which were caught from trawlers (AFMA, 2007b).
Estimates of biological parameters (such as growth rate) are considered to be poor, based on lack of data for small specimens (Bruce et al., 2002).
Across the range, a research program on most aspects of the biology and population dynamics is required.

Other Information

Hapuku are found in caves and crevices, in a number of protected reserves in New Zealand, such as the Poor Knight Islands, where dive charters visit for fish-viewing.