© 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.

---

Samsonfish / Sea Kingfish

Family Name:	Carangidae
Scientific Name:	Seriola hippos (Günther, 1876)
Recommended Status:	Southern Australia (incl. SA & WA): Data Deficient, possibly Near Threatened
Rationale:  Although Samsonfish has a broad geographic distribution across southern Australia, and is an abundant species, it is included here because (i) it is a large, aggregating, species that is easy to target around natural and artificial reefs (the latter including shipwrecks, around which seasonal aggregations occur in some parts of the range). In some areas, aggregations form predictably over space and time. These characteristics increase the susceptibility of Samsonfish to over-exploitation; (ii) the species is classified globally as being of low resilience, and having “high to very high vulnerability” to fishing-induced population decline; (iii) in W.A., where Samsonfish is ranked as a “high risk” species, in terms of likely population impacts from fishing, the burgeoning popularity of jig-fishing upon spawning aggregations has increased the vulnerability of populations to impact. There is a significant, but inadequately investigated issue regarding possible mortality rate of Samsonfish that are caught and released during deep water jigging and charter boat fishing (e.g. from waters 50m – 100+m). Also, there may be additional mortality from increased shark predation on caught and just-released fish, including predation on large, pre-spawning females; (iv) given the size, it is possible that Samsonfish are a relatively long-lived species, a characteristic that would increase vulnerability of populations to over-exploitation. There is inadequate information on population sizes and connectivity across the range (despite the regular commercial and recreational fishing of this species, including spawning aggregations in some areas), age and growth, longevity, reproduction and year class strength, diet, species interactions, and habitat.

Page Contents

Current Conservation Status

There are no formal listings for this species, but Samsonfish is classified as a “high risk species” by the Department of Fisheries in Western Australia.

Distribution

Global

Samsonfish is found around Australia (Paxton et al., 1989), New Zealand (Francis, 1993), and Norfolk Island.

Australia

In Australia, the species occurs from southern Queensland (Moreton Bay) through to Shark Bay in W.A., including Bass Strait islands and northern Tasmania area (Hutchins and Swainston, 1986, 2001; Gomon, in Gomon et al., 1994; Australian Museum records, South Australian Museum records; Museum of Victoria records, cited in OZCAM database, 2008).

South Australia

In S.A., Samsonfish has been recorded along western Eyre Peninsula / eastern Great Australian Bight (e.g. Fowlers Bay; Streaky Bay, Sceale Bay and other bays); southern Eyre Peninsula (e.g. Rocky I., Greenly I., Four Hummocks), Spencer Gulf (e.g. Port Lincoln area; Tumby Bay; Wallaroo / Port Hughes), southern Yorke Peninsula (e.g. Marion Bay, Stenhouse Bay), the Gambier Isles (e.g. Wedge), Kangaroo Island, and Encounter Bay (ANSA, 1999; Game Fishing Association of Australia, 1999; ABC, 2007; FishNet, 2004, and other recreational fishing and charter boat trip reports, Department of Fisheries WA, 2007b); WA Fisheries, 2007; Hutson et al., 2007; J. Baker, pers. obs., 2008; S.A. Museum records, cited in OZCAM database, 2008; R. Foster, S.A. Museum, pers. comm., 2008).

Habitat

Generally, Samsonfish occur in small schools or pairs around rocky reefs and wrecks, especially in deeper coastal waters (Gomon, in Gomon et al., 1994). Maximum depth may be more than 150m, as evidenced by trawl records from the western Great Australian Bight (CSIRO Marine Research data, 1967, cited in CSIRO, 2009).

In New South Wales, Lincoln-Smith and Hair (1990) noted the significance for Samsonfish of shallow rocky reefs and rocky shores in the Sydney, Jervis Bay and Batemans Bay areas.

Fishers in S.A. and W.A. have caught Samsonfish on offshore reefs, particularly between 50m – 80m, but also inshore, around jetties and rock groynes.

During a survey of habitats in the Recherche Archipelago, Seriola hippos was recorded in a variety of habitats, including the following (in decreasing order of percentage of samples within each habitat category where fish species were seen): sand-inundated reef with sparse macroalgae; “unknown” reef; bare sand; reef with macroalgae of medium density; medium-density seagrass beds; reef with dense macroalgae (including Ecklonia) and sparse-density seagrass beds (Harvey et al., 2004).

In W.A., Samsonfish are recorded inshore on reefs, and around jetties / piles and channel markers (Dybdahl, 1979; Harrison, 2001; Stagles, 2008), and also in continental shelf waters, associated with offshore reefs (including lines of calcareous reef, and coral “bommies”: e.g. Morse, 2006), and artificial reef structures such as shipwrecks (e.g. HMAS Swan wreck – Taylor, 2005, and Key Biscayne – Morse, 2006), around which they often form schooling aggregations (Department of Fisheries WA, 2004h; Stagles, 2008).

Samsonfish are reported to occur mainly in warmer waters (18-24°C), but are occasionally found in cooler waters (of the south coast) (Starling, 1988, cited in Froese and Pauly, 2009). This species is often found in area of high current strength.

Samsonfish are occasionally recorded in the outer reaches of estuaries (e.g. Lenanton and Potter, 1987), with examples including Peel-Harvey Estuary (Malseed and Sumner, 2001; Swan River Estuary: Smith, 2006).

Notes on Biology and Behaviour

Age and Growth

Samsonfish reach a maximum length of about 175cm, and a maximum weight of at least 53kg (Hutchins and Swainston, 1986; 2001; Kailola et al., 1993; Gomon, in Gomon et al., 1994). According to Morse (2006) and Stagles (2008), fish larger than 53kg (and up to 60kg) have been caught in recent years in spawning aggregations off Rottnest Island in WA.

One example of the size of adult fish in an aggregation is 120 - 160cm, and 20 - 45kg (e.g. FRDC, 2005).

Migration / Aggregation

In W.A., more than 9,000 Samsonfish have been tagged, largely at a spawning aggregation site near Rottnest Island (Department of Fisheries WA, 2007b). Tagged fish generally moved southwards from the site of tagging, along the southern coast of WA and into the Great Australian Bight, with some travelling as far as Kangaroo Island in South Australia (ANSA, 2007; Department of Fisheries WA, 2007b). Travel speeds can be high. For example, one fish was recaptured south-east of Esperance (1,100km away from the tagging site) after being at liberty for only 26 days (moving at a average rate of about 42km/day). Fish that dispersed from the aggregation near Rottnest Island travelled more than 900km in less than four weeks (FRDC, 2005). One fish tagged off Perth was recovered off Hopetoun 28 days later (W.A. Department of Fisheries, 2005). Fishers (e.g. Morse, 2006) have reported that fish tagged in the Perth area often head southwards, and have been caught by anglers off Bunbury, and further east into the Great Australian Bight.

Data from tag returns in the W.A. study cited above, indicate a mass migration of Samsonfish from the waters of the south coast, and these fish join the spawning aggregations west of Rottnest Island. Individuals may only stay in the aggregations for short periods (several weeks) before returning to the south coast. Tagged Samsonfish often returned to the large spawning site near Rottnest Island in WA during the spawning season. Data also indicate that individuals return to the spawning areas at the same time each year, and most fish are recaptured in the same month as they were tagged in the previous year(s) (Murdoch University, 2006).

In South Australia, 73 specimens of S. hippos were tagged during a program that ran between 2004 and 2006, in Spencer Gulf and offshore from the west coast of Eyre Peninsula. Two specimens were recaptured, of which one was at liberty for a maximum of 378 days. Both S. hippos were recaptured at the original capture site (Hutson et al., 2007).

Samsonfish aggregate around structures, in some areas. For example, at Rottnest Island, this species aggregates around a shipwreck at about 100-110m deep, and a Samsonfish aggregation up to 30+m deep has been recorded in the vicinity of the wreck. In this area, three separate aggregations have been recorded with fish moving between the aggregations (FRDC, 2005). Morse (2006) reported that aggregations can be 1000m long, and 40m deep, with Samsonfish commonly at depths of 60m to 100m in the aggregation.

In New South Wales, recreational fishers report that this species swims in small schools or pairs as they become larger.

Reproduction

In W.A., Samsonfish migrate to spawn collectively, and large spawning aggregations have been recorded. These aggregations are predictable over space and time (e.g. Anonymous, 2005; W.A. Department of Fisheries, 2005; Parsons et al., 2006).

Behaviour

Samsonfish are very strong swimmers. They are also curious, and have often startled divers as they dash in to investigate their presence (Gomon, in Gomon et al., 1994).

Fisheries Information

Southern Australia – Commercial (Commonwealth Fisheries)

A summary of Commonwealth-managed fisheries in which this species is reportedly caught, include the Coral Sea Fishery (by-product); Eastern Tuna and Billfish Fishery (by-product); Gillnet, Hook and Trap Fishery = South East Non-Trawl Fishery and Southern Shark Fishery (by-product); Great Australian Bight Trawl Fishery (by-product); and South East Trawl Fishery (by-product, but insignificant numbers caught, according to Wayte et al., 2004) (Bromhead and Bolton, 2005).

In the Southern and Eastern Scalefish and Shark Fisheries, Samsonfish may be taken with a concession that allows fishing methods other than trawl (AFMA, 2005b). The species may be caught in Commonwealth waters (outside 3 nm) but not in coastal waters (inside 3nm) with a concession that allows methods other than trawl, and there are no Commonwealth catch limits (AFMA, 2005b).

Southern Australia – Commercial (State Fisheries)

In Queensland, Samsonfish are caught with hand lines and gillnets. Because Samsonfish and Amberjack are similar in appearance, the name Samsonfish is usually used interchangeably by fishers (both commercial and recreational) to describe the two common species taken. In southern Queensland, the northern end of the species’ range in eastern Australia, Samsonfish experience high fishing effort from line fishers in addition to effort by deepwater fishers (Sumpton and Ryan, 2004). Samsonfish are caught in Queensland’s L8 (deepwater multiple hook) fishery, and although the species is not a primary target, it is often caught along with various target species. About 50% of the catch is reportedly taken with drop/trot lines, 10% with hand lines and 39% with other lines (White and Sumpton, 2002). Samsonfish and Amberjack are widespread, and catches are recorded from all areas, both north and south, in deep waters as well as shallower waters within the Great Barrier Reef Marine Park (White and Sumpton, 2002). In Queensland, Samsonfish forms part of the Rocky Reef Fin Fish Fishery (RRFFF), and during the past 11 years to 2007, annual catches have ranged between 2t and 8t (DPIF Queensland, 2008). Previous catches (e.g. 1960s to 1980s) were also reported less than 10t per annum (BRR, 1991).

New South Wales: Samsonfish are taken by commercial reef fishers in N.S.W. (Brooks, 2000). As early as the first decade of the 20th century, this species was promoted as a potentially valuable target for hook and line fishers in New South Wales, and was occasionally seen in markets at the time (Stead, 1908). A map by BRS (2004) indicated that annual catches from south-eastern Australia (mainly off the N.S.W. coast) were around 10t-15t in 2001 and 2002, and around 20t in 2000, but the accuracy of these figures is not known for this report. According to McLennan (1999) annual catches from 1989/90 to 1996/97 in New South Wales were as follows: 0.5t, 5.5t., 12.8t, 18.7t, 19.2t, 15.8t, 54.6t and 20t. Samsonfish catches are incidental in the N.S.W. Ocean Trawl fishery. Small numbers are taken in the bycatch of fish trawls and prawn trawls (e.g. 12kg and 14kg respectively, in 2000/01) (New South Wales DPI, 2004). Schnierer and Faulkner (2002) reported that Samsonfish is targeted commercially in an indigenous fishery in southern New South Wales.

In South Australia, the species is listed as a commercial species in the Marine Scalefish Fishery, but in some years, no catches are made.

Western Australia: This species is also a significant part of the scalefish by-catch in the Western Australian temperate demersal gillnet and demersal long-line shark fishery, particularly on the West Coast (i.e. the WCDGDLF sector). During a bycatch survey from 1994 to 1999, Seriola hippos comprised an average of 10% and 11% of the annual scalefish catch in Region 5 (between latitudes 33°S and 30°S) and Region 6 (between latitudes 30°S and 27°S) respectively, with most specimens between 70 and 110cm fork length (FL). Total numbers observed in the bycatch during each year of survey from 1994/95 to 1998/99 were as follows: 48, 52, 8, 19, 71 specimens, with the majority coming from the two regions of the west coast of W.A. specified above (McAuley and Simpfendorfer, 2003). In the WA temperate shark fisheries, Samsonfish accounted for 17% of the scalefish catch from the west coast in 1995/96; 4% from the south-east coast, and 2% from the south coast (Simpfendorfer et al., 1997). In 2001/02, the scalefish catch of this fishery accounted for 22%, by weight, of the total catch. Samsonfish is one of the top 5 scalefish species taken in the WCDGDLF, with a catch of almost 12t in 2001/02 (Borg and McAuley, 2004). The catches in 2003/04, 2004/05 and 2005/06 were about 12t (NB also equals 12% of the scalefish catch for that year), 24t and 16t respectively (McAuley, 2005; W.A. State of the Fisheries report, 2006/07). The catches in the Joint Authority Southern Demersal Gillnet and Demersal Long-line Fishery (JASDGDLF) are lower; e.g. 6t in 2003/04 (McAuley, 2005), and 4t per annum in 2004/05 and 2005/06 (W.A. State of the Fisheries report, 2006/07). In WA, during the early 2000s, Samsonfish was one of the top 10 catches in the “wet-line” fishery catch (e.g. 61t in 2000/01), with the majority of this coming from the West Coast bioregion (Department of Fisheries WA, 2002). In the West Coast region, 75t of Samsonfish were taken in 2002/03, making it the 6th most important scalefish taken in that fishery in terms of catch weight (W.A. Department of Fisheries, 2005c). At the Abrolhos Islands, Sumner (2008) reported that commercial “wet-line” fishers caught and kept 8.5t on Samsonfish in 2006. Samsonfish is also one of the top 10 species taken in the South Coast “wet-line” fishery, with 14t taken in 2001/02; 15t in 2002/03 and 10t in 2005/06 (W.A. State of the Fisheries reports, 2004/05, 2005/06 and 2006/07). The total Samsonfish catch by commercial line fishers in W.A. waters was estimated to be 75t in 2002/03 (W.A. Department of Fisheries data, cited in Baker, 2007b). Samsonfish are caught in very minor quantities in the commercial fishery operating in the Swan – Canning estuary in W.A. (e.g. average annual catch of 12kg recorded between 1995 and 2004) (Smith, 2006). In W.A., Samsonfish is also a bycatch species in the Shark Bay prawn fishery, and are caught using line gear by operators who also run trawls (Bunting, 2002). The total recorded catch of Samsonfish from W.A. waters is shown below, for the period 1997-2007. Annual reported catches from WA waters ranged between 85t and 108t per annum, between 1989 and 1996 (McLennan, 1999). Prior to that, annual reported catches were in the order of 30t – 80t per annum from the mid 1960s to the mid 1970s; usually less than 40t per annum from the mid 1970s to mid 1980s, and 40t to more than 100t per annum from the mid 1980s to early 1990s (BRR, 1991).

Reported Catches of Samsonfish from W.A. waters, 1997 to 2007
Year	Samsonfish live weight (kg)
1997/98	138,467
1998/99	99,628
1999/00	102,110
2000/01	95,530
2001/02	113,011
2002/03	115,302
2003/04	102,773
2004/05	94,610
2005/06	80,704
2006/07	63,072
(W.A. State of the Fisheries reports, 1998/99 – 2007/08)

Southern Australia – Recreational

Samsonfish is an important fish species for recreational fishers in southern Australia, and is fished in all southern Australian States. Various angling clubs and associations (e.g. International Game Fishing Association) around southern Australia and the Pacific promote Samsonfish for its size, strength and fighting abilities. Many clubs and associations (e.g. Australian National Sportsfishing Association) keep records of the maximum sizes caught.

Samsonfish are caught by sports fishers (including charter boats) as a primary target species in Queensland (Moore et al., 2007); and in New South Wales. In 1997/98, a survey in N.S.W. showed that almost half of all charter boats in that State targeted Samsonfish (i.e. 111 of 240 charter boats, according to Steffe et al., 1999). Examples of locations in New South Wales where this species is caught include Coffs Harbour; Hawkesbury – Nepean areas; parts of Sydney Harbour, and around Lake Macquarie. Angling Clubs (e.g. New South Wales Fishing Clubs’ Association) keep records of the maximum sizes caught by anglers.

This species was one of the targets in the 4th Sport Fishing World Champion Cup (Fishing World Cup) in 2008, at the Gold Coast, Queensland.

Charter boats in South Australia and Western Australia target large Samsonfish offshore. In W.A., Morse (2006) promoted the use of fly fishing gear to capture this species when charter boats visit the spawning aggregations west of Rottnest Island. Jig fishers have also exploited the spawning aggregations, and this is an increasingly popular method. Morse (2006) reported that some experienced jig fishers have caught and released over 30 Samsonfish per day, with an average weight of about 24kg per fish. In W.A., recreational fishers catch this species both north (e.g. Kalbarri area, and Abrolhos Islands) and south (e.g. Bunbury) of the spawning aggregations off Perth / Rottnest (Morse, 2006). In the West Coast region (Augusta to Kalbarri), Sumner et al. (2008) estimated a recreation boat-based catch of 24 tonnes (SE = 3t) in 2005/06, compared with 35t (SE = 12t) in 1996/97. Within areas of the West Coast region, the main catches came from the metropolitan area (13t in 2005/06 and 19t in 1996/97), followed by the southern area (7t in 2005/06 and 8.4t in 1996/97) and the mid-west area (3.8t in 2005/06 and 6.6t in 1996/97). The total catch of Samsonfish by fishers with trailer boats in the Augusta to Kalbarri area, was estimated to be 5,687 fishes (SE = 629), with 2,934 fishes released. In W.A. the species is caught by charter boat game fish anglers, and by jig-fishing, off locations such as Bremer Bay (e.g. off rock ledges), Denmark, Albany, Bremer Bay, Geographe Bay, Augusta, Cape Naturaliste, Margaret River, Yallingup, Busselton, Bunbury, Mandurah, Cockburn Sound, Rockingham, Rottnest Island, reefs offshore from Fremantle, Hillary's Boat Harbour, Mindarie, Two Rocks, Jurien Bay, Dongara, Kalbarri and Abrolhos Islands (W.A. charter boat and recreational fishing records, 2005-2009). It is estimated that in 2002, 428 Samsonfish were kept (~ 4 tonnes), and 81 released, from tour boat operations (Department of Fisheries, WA, 2004d). In 2002/03, the estimated charter boat catch of Samsonfish was 16.5t from the West Coast bioregion, and 4.5t from the South Coast bioregion (W.A. State of the Fisheries report, 2003/04). Samsonfish is a main target of charter boats along the West Coast bioregion in W.A.. Charter catches of Samsonfish from that area were estimated to be 18t in 2002 and 15t in 2003 (W.A. State of the Fisheries report, 2003/04). Along the south coast of W.A. Samsonfish are an important recreational species for anglers and charter boats (W.A. recreational fishing reports, 2007-2009). As much of the south coast is remote or difficult to access, recreational boat fishing tends to be concentrated around the main population and holiday centres. Samsonfish is one of the 6 main species targeted by boat anglers in that area (W.A. State of the Fisheries report, 2003/04). Reported charter boat catches along the south coast bioregion of W.A. were about 6t in 2002 and 3t in 2003 (W.A. State of the Fisheries report, 2003/04). A number of charter boat companies and fishers’ reports indicate that jigging for Samsonfish has become more popular in Western Australia in recent years. In W.A., Samsonfish are reported to be a much sought after species for an increasing number of anglers (Stagles, 2008). Apparently, the increasing popularity of “deep water jigging” has significantly increased the popularity of Samsonfish as a target for offshore anglers, and international anglers also visit W.A. specifically to tackle Samsonfish from 100+m waters (Stagles 2008). Malseed and Sumner (2001) reported that fishers also catch Samsonfish in the Peel-Harvey estuary system. In W.A., Samsonfish are also caught off jetties and groynes in some areas (e.g. Cockburn Sound - Dybdahl, 1979). This species is also targeted in fishing competitions in parts of southern W.A. (Game Fishing Association of Australia, 1999; Stagles, 2008), and various clubs and association keep records of maximum sizes caught in competitions (e.g. Surf Casting and Angling Club of W.A. Inc.; Lancelin Angling and Aquatic Club Inc.).

In South Australia, Samsonfish are caught occasionally off jetties, but more commonly in deeper waters, by charter boat fishers and other offshore anglers. Examples of locations include north-western Kangaroo Island / Investigator Strait; southern Kangaroo Island; Yorke Peninsula – including waters off Innes National Park; Gambier Islands group (e.g. Wedge Island); southern Eyre Peninsula and offshore islands (e.g. Rocky and Greenly, and the Whidbey Islands); locations out of Spencer Gulf; eastern Great Australian Bight, such as off Sceale Bay and Streaky Bay, off Ceduna, Point Fowler and Fowlers Bay, Flinders Reef and Nuyts Archipelago) (Game Fishing Association of Australia, 1999; McLeay et al., 2003; Baker, 2004 and references therein, including Fishnet reports; Hunt, 2007; charter boat advertising materials, 2005-2009). In the eastern Great Australian Bight, charter vessels visit bays, islands (e.g. Flinders Reef and Nuyts Archipelago), and other areas to catch species such as S. hippos (McLeay et al., 2003). In, S.A., Samsonfish are targetted in game fishing competitions e.g. Game Fishing Club of South Australia's Pt Lincoln Blue Water Classic.

In the National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003), Samsonfish catches were grouped with Kingfish (S. lalandi) catches, and it is not possible to separate the statistics for each species. A minimum of 114,053 Kingfish and Samsonfish combined were caught and kept across Australia by recreational fishers during the survey period (May 2000 to April 2001), which included 5,121 from Queensland; 90,001 from New South Wales; 375 from Victoria; 1,505 from Tasmania; 6,160 from South Australia; and 10,890 from Western Australia. The proportion of these catches that refer only to Samsonfish cannot be determined from available data.

The species is occasionally caught by spearfishing. Two of the maximum weights recorded by spearfishing are 43.36kg, being a specimen caught at Cowaramup (south-western W.A.) in 1962, and 39kg, a specimen caught in Coolum, Queensland, in 1969 (Australian Underwater Federation Inc., 2003, 2004). The species is also caught by spearfishing in N.S.W. (e.g. Coffs Harbour Bluewater Freedivers, 2006; Newcastle Neptunes Underwater Club, 2008; Underwater Skindivers and Fisherman's Association Inc., 2007). During the 2000s, spearfishing charter trips were run out of the Shark Bay / Dirk Hartog Island area, with Samsonfish being one of the target species.

Vulnerable Population Characteristics and Threatening Processes

Samsonfish are large, aggregating species that are easy to target around natural and artificial reefs (the latter including shipwrecks, around which seasonal aggregations occur in some parts of the range). In some areas, aggregations form predictably over space and time. These characteristics increase the susceptibility of Samsonfish to over-exploitation. The species is classified globally as being of low resilience, and having “high to very high vulnerability” to fishing-induced population decline (Cheung et al., 2005, cited in Froese and Pauly, 2009).

In W.A., Samsonfish is listed amongst the “prize fish” or “trophy fish”, which are highly sought after for their catching or eating qualities and some are vulnerable to overfishing, and of low abundance. The species is ranked as having moderate to high eating and fishing value; moderate vulnerability due to fishing and environmental factors; with little biological data; moderate to increasing fishing pressure, and insufficient data to determine level of risk of over-exploitation (Department of Fisheries WA, 2004h). It has been classified as a “high risk” species (e.g. Stagles, 2008), in terms of likely population impacts from fishing.

In W.A., the burgeoning popularity of jig-fishing upon spawning aggregations has increased the vulnerability of populations to impact. There is a significant, but inadequately investigated issue regarding possible mortality rate of Samsonfish that are caught and released during deep water jigging and charter boat fishing (e.g. from waters 50m – 100+m). Additionally, there is some indication from fishing reports, that increased shark predation is occurring on hooked or just-released Samsonfish, and a number of these fish are large, pre-spawning females. In Queensland, Samsonfish was ranked 10th (of 46 species) in terms of susceptibility to high post-release mortality in fishing operations (Sumpton and Ryan, 2004), and has high catchability. However, the species has been ranked as low to moderate in terms of risk of fishing pressure and over-exploitation (Sumpton and Ryan, 2004).

According to Winn (2006), in a submission on marine protected areas by the New South Wales National Parks Association, the peak annual catch of Samsonfish in N.S.W. was 55t (according to catch statistics from 1940 to 2000), and the catch declined to 10t by the year 2000.

Given the size, it is possible that Samsonfish are a relatively long-lived species, a characteristic that would increase vulnerability of populations to over-exploitation. There is inadequate information on population sizes and connectivity across the range (despite the regular commercial and recreational fishing of this species, including spawning aggregations in some areas), age and growth, longevity, reproduction, diet, species interactions, and habitat.

Research Notes

During the mid 2000s, a PhD student at Murdoch University in Western Australia (A. Rowland) undertook a project on the biology and ecology of Samsonfish, with emphasis on the sports fishery that targets deep water spawning aggregations west of Rottnest Island. The research, in which the WA Department of Fisheries and Recfishwest are collaborators, aims to determine fishing mortality, catch care and fish handling protocols to maximise the survival of released fish. The project forms a major component of a collaborative project lead by the Department of Fisheries Western Australia (FRDC Project 2004/51 - Management and monitoring of fish spawning aggregations within the West Coast Bio-region of Western Australia).

In 2005, more than 270 recreational fishers worked with researchers from WA Fisheries, Murdoch University, Curtin University and the University of Western Australia, to catch and tag almost 2,500 Samsonfish in spawning aggregations off Rottnest Island. This species was selected as the first in a broader study, funded by Fisheries Research and Development Corporation (FRDC), to study the monitoring methods and other management measures needed to protect spawning aggregations in W.A.’s West Coast Bioregion. Some of the major objectives of the Samsonfish study were to gather information about the biology (including migration patterns) and ecology, and establish monitoring methods and sport-fishery protocols. Studies are also being carried out on the post-release survival and diet of Samsonfish. Video, acoustic and other sampling methods developed on the Samsonfish schools are also being used to research more vulnerable species that aggregate to spawn, such as Dhufish and Pink Snapper (FRDC, 2005). Additional tagging work was planned north and south of the main aggregation, for subsequent years (FRDC, 2005), and by 2007, more than 9,000 Samsonfish had been tagged, largely at the spawning aggregation site near Rottnest Island (Department of Fisheries WA, 2007b).

During the mid 2000s in W.A., a project was being undertaken (by M. Parson, Curtin University of Technology), using passive and active acoustic techniques to assess biomass and other characteristics of spawning aggregations of Samsonfish. Field research for the project involves: acquiring single and multi-beam data from aggregations; logging recordings of spawning vocalisations; simultaneous ground truthing data using physical sampling; and establishing fish backscatter strengths in controlled situations. Several sites along the Western Australian coast are being targeted, where recurring spawning aggregations have been reported. The various acoustic methods will be evaluated against ground-truthing data and model predictions. Resulting conclusions will be used to develop protocols to promote accurate and cost effective measurement of biomass levels for particular aggregations (e.g. Parson et al., 2006; Curtin University Centre for Marine Science and Technology, 2007).

During the mid 2000s, scientists (e.g. M. Mackie) and students from the WA Department of Fisheries and Curtin, Murdoch and Edith Cowan universities were tracking the movement of various fish species that aggregate off the coast, including the spawning aggregations of Samsonfish west of Rottnest Island. The research utilised acoustic tags to monitor movement patterns; single and multi-beam echo sounders to describe aggregations and hydrophones (underwater microphones) to identify where, when and how many individuals are aggregating. The project was funded by the Fisheries Research Development Corporation, and results will be used to improve monitoring of Samsonfish stocks in WA, and assist management of the fisheries for that species (Amalfi, 2005).

In South Australia, a University of Adelaide tagging program has being undertaken, in conjunction with SAFTAG (South Australia's branch of the Australian National Sportfishing Association's tagging programme), and Adelaide Game Fishing Club. The project aimed to learn more about the timing and nature of Samsonfish migrations. From 2004 to 2006, 73 specimens of S. hippos were tagged in Spencer Gulf and offshore from the west coast of Eyre Peninsula (Hutson et al., 2007).

In South Australia, the Centre for Evolutionary Biology and Biodiversity (University of Adelaide and S.A. Museum) has undertaken a survey of parasites from wild and farmed carangids (including S. hippos) in southern Australia (CEEB, 2005). The widely distributed flatworm parasite, Benedenia seriolae (which may be a species complex) is a significant pathogen of Seriola species in Japan, New Zealand, Australia, Chile, Hawaii and Mexico, and molecular genetic work is being undertaken to investigate the co-evolution of the parasite and its hosts.

In recent years, a number of papers have been published on the parasites that infect Seriola hippos (e.g. Bray and Crib, 2001; Lymbery et al., 2002; Tang and Kalman, 2005; Hutson and Whittington, 2006; Hutson et al., 2007).

Samsonfish is one of the species included in a long-term gamefish tagging program of catch and release in New South Wales. Pepperell (2000) reported that 579 Samsonfish were tagged and released between 1974 and 1997.

In Queensland, a Long Term Monitoring Program (LTMP) for rocky reef fishes, is using fishery dependent sampling to collect age, length and sex data representative of the commercial, recreational and charter boat catches in south east Queensland. One of the secondary target species is Seriola hippos, for which data are being collected opportunistically throughout the program (DPIF, Queensland, 2007).

Management Notes

Previously in W.A., there was a combined bag limit of 10 per day, for any combination of the reef species Coral Trout, Baldchin Groper, Red Emperor, Samsonfish, Pink Snapper, North-west Snapper and Blue Morwong (Hancock, 1991). Currently in W.A., where Samsonfish is classified as a “high risk species”, there is a minimum legal size of 60cm, and a bag limit of 2 Samsonfish in the South Coast, West Coast and Gascoyne bioregions (Department of Fisheries WA, 2008c, 2009a,b).

In W.A., there are small areas where fishing for Samsonfish is prohibited. Closed areas include the anchorage areas of inhabited islands in the Abrolhos Islands group, and includes North Island, Wallabi Group, Easter Group, and Southern Group. This is part of the Abrolhos Islands Fish Habitat Protection Area (W.A. Department of Fisheries web site, 2009).

In W.A., there is a publication titled “Catching and Caring for Samsonfish (Seriola hippos)” (Mackie et al., 2007), which provides detailed advice to help fishers minimise mortality of Samsonfish caught and released during game fishing, and also encourages fishers to report details of tagged Samsonfish that are caught and released.

In South Australia, the minimum legal size of Samsonfish taken by recreational fishers is 75cm (from tip of snout to tip of tail), and there is a daily bag limit of 2, and a boat limit of 6 Samsonfish (PIRSA web site, 2009). For charter boats carrying more than 3 but not more than 6 passengers, the daily boat limit is 6 Samsonfish. The number per person per day is 2 for charter boats carrying not more than 3 passengers, and 1 for charter boats carrying more than 6 passengers.

The FRDC-funded Release Fish Survival (RFS) project, part of Recfishing Research, has produced a DVD to promote a national code of practice for catch and release of game fish such as Seriola hippos, and discusses outcomes of RFS projects on this species (Recfishing Australia Annual Report, 2005-06). There was also a brochure released in 2007 by the W.A. Department of Fisheries, on Catching and Caring for Samsonfish, and this code of practice arose from the results of research on catch care and handling practices (see Research Notes).

Research and Management Recommendations

There is inadequate information on population sizes and connectivity across the range (despite the regular commercial and recreational fishing of this species, including spawning aggregations in some areas), age and growth, longevity, reproduction, diet, species interactions, and habitat. The biology, population dynamics and ecology of this species are all poorly known, despite the high fishing mortality, especially from recreational and charter boat fishing, and from commercial bycatch in shark fisheries.

The mortality rate of Samsonfish that are caught and released during deep water jigging and charter boat fishing (e.g. from waters 50m – 100+m) should be further assessed across the range (particularly in WA and SA), and some initial work has been undertaken in the Rottnest area (see Research Notes). Issues surrounding this practice include mortality from the catch and release process, and additional mortality from increased shark predation on caught and released fish.

Seasonal and/or permanent closures should be considered in some areas, particularly locations in which Samsonfish aggregate to spawn. All major spawning grounds should be protected during the spawning season.

Fishing of spawning aggregations (e.g. off Rottnest Island) should be prohibited.

Fishers should adhere to the recommendations in the W.A. Department of Fisheries (2007) document “Catching and Caring for Samsonfish Seriola hippos”.

Other Information

Pepperell (2000) reported that between 1974 and 1997, a total of 3,933 Samsonfish were tagged in the Australian Gamefish Tagging Program (operated by New State Wales Fisheries), but overall, there was only a 3% recapture rate.

In Western Australia, there is a tourism enterprise at the Abrolhos Islands, where large (e.g. 30kg) Samsonfish are hand-fed by tourists.