© 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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Striped Trumpeter / Tasmanian Trumpeter

Family Name:	Latridae
Scientific Name:	Latris lineata (Forster, in Bloch and Schneider, 1801)
Recommended Status	South Australia: Data Deficient; South-Eastern Australia (including Commonwealth waters): Data Deficient; Commonwealth Waters: possibly Near Threatened
Rationale:  Although Striped Trumpeter is a common reef species in parts of south-eastern Australia, particularly Tasmania, it is included here because (i) it is a large, relatively long-lived, site-associated fish species in reef habitats, and species with such population dynamics and habits are vulnerable to decline from over-exploitation; (ii) juveniles are strongly site-associated with inshore reefs, and because this species is highly prized as a food fish by both commercial and recreational fishers, and is easily found and caught, it is therefore vulnerable to over-exploitation (including growth-overfishing); (iii) this species matures at a large size (more than 50cm), and the minimum legal size in Tasmania is lower than the size at first maturity, and a proportion of fish caught have not had the opportunity to spawn. In other parts of southern Australia there are no minimum size limits, and the proportion of reproductively immature fish that is taken has not been determined; (iv) Striped Trumpeter exhibit strong recruitment variability from year to year, with long periods (e.g. up to decadal scales) of poor recruitment, which increases the susceptibility of populations to gradual decline if fishing remains high during years of poor recruitment; (v) Striped Trumpeter is reported to have a very low resilience to exploitation, and high to very high vulnerability to fishing-induced population decline; (vi) population size is unknown in any area (including Tasmania, where this species has been heavily fished over a long period), and the details of offshore migration with size / age are not known. Catch and effort are highest in Tasmania, where there are no biomass estimates; catch rates are likely to be a poor indicator of stock abundance, and stock status is reported to be uncertain. However, in Tasmania, concern has been raised about apparent depletion of the stock due to the effects of fishing (both inshore and offshore), coupled with apparent poor recruitment during the past decade (and this has likely also occurred during periods of the 19th and 20th centuries). Management is hindered by the multi-sector and multi-gear nature of the catches; also the fact that this species is taken as a target species in some fisheries, and as by-catch in others; and is migratory at large sizes / older ages. In South Australia, the catch by commercial and recreational fishers and charter boats is unknown, but potentially low. There is very little information on the geographic distribution, and no data on the abundance of Striped Trumpeter in South Australia. No data are available over space and time to indicate the status of the population in South Australia.

Page Contents

Current Conservation Status

There are no formal listings in Australia; however, it is noted that in New Zealand, a conservation assessment of fished species, aimed at influencing fish consumer choices (Weeber and Szabo, 2004, 2005), ranked Latris lineata as “E” (i.e. in the “Red” species list – to be avoided by consumers), based on lack of knowledge of sustainable catches, lack of stock assessment, and the belief that that localised populations can be quickly fished down.

In eastern Tasmania, the species is considered to be fully fished (Smith and Heran, 2001). During the early 2000s, assessment of the fishery in Tasmania reported that “although more rigorous assessment than is possible through examination of commercial catch data is required to assess the sustainability of the fishery, catch and effort need to be monitored closely over the coming years. Even without such an assessment, the expectation is that this fishery is declining and will continue to do so without action. It would be prudent to act to reduce fishing mortality in some significant manner” (Lyle and Hodgson, 2002, p. 27; Lyle et al., 2004, p. 67).

Distribution

General

Striped Trumpeter is widely distributed in temperate latitudes of the southern hemisphere (Tracey, 2007). It occurs in southern Australia, New Zealand (particularly south of Cook Strait and Bay of Plenty, and around the South Island) and the Chatham Islands, St Paul and Amsterdam Islands, and Tristan da Cunha group and Gough Island (Paulin et al., 1989; Roberts, 1991; Lyle, 1995; Kuiter, in Gomon et al., 1994; Andrew et al., 1995; Australian Bureau of Statistics, 1996; Edgar, 2000; Anonymous, 2000c).

In and around New Zealand, the species is considered to have a cool temperate distribution, being occasionally found off the north-east of the North Island, and north of East Cape, but mainly known from the southern part of the North Island, and the South Island; also Stewart Island, Snares Islands, Auckland Islands, and Campbell Islands (Francis, 1996).

Southern Australia

Within Australia, the species is found in southern NSW, Victoria, Tasmania, S.A. and southern W.A., with Albany being the published western limit (Hutchins and Swainston, 1986; Kuiter, in Gomon et al., 1994; Edgar, 2000; Gomon et al., 2008). Of the Australian States, the species is most common in Tasmania, and is considered to be characteristics of the Tasmanian bio-province (Edgar et al., 1995).

South Australia

Locations in South Australia where the species is found include Kangaroo Island (DPIWE Tasmania, 2005a). It is likely that Latris lineata also occurs offshore in south-eastern South Australia, but specific records could not be found for this report.

Habitat

Striped Trumpeter are found over rocky / rough bottom habitats, mainly on the continental shelf, at depths ranging from the shallows to about 300m deep (Kuiter, in Gomon et al., 1994; Lyle, 1995; Australian Bureau of Statistics, 1996; CSIRO et al., 2001).

Adults of this species are usually found over deep offshore reefs (50m – 250m) (Tracey, 2007), and on top of underwater pinnacles (Fishnet, 2004). In New Zealand, this species apparently prefers “broken” rocky reefs, rich in sessile invertebrate cover. Striped Trumpeter is reported to be frequently found over rocky places, especially narrow channels between two cliffs, in fjords of New Zealand (Roberts, 2003, cited in Froese and Pauly, 2009). During a survey of fish-habitat relations in south-eastern Australia, Striped Trumpeter was reported to be closely associated with rocky reefs (Williams and Bax, 2001).

Striped Trumpeter now inhabit mainly deep offshore waters of the continental shelf, or around remote coastal sections of southern and western Tasmania, and are more numerous in south-eastern Australia than in other parts of the range (Hutchins and Swainston, 1986; Edgar, 2000). Previously, the species was common around shallow coastal reefs in Tasmania, but heavy fishing during the past half century is reported to have depleted shallow water populations (Hutchins and Swainston, 1986; Edgar, 2000).

In Tasmania, a project used otolith microchemistry to determine the contribution of juvenile Striped Trumpeter from shallow inshore habitats to the adult population offshore, and results indicated that 70% of adults sampled in offshore waters came from inshore juvenile habitat several years earlier, and 13% were from deeper reefs (Tracey, 2007).

In some parts of Tasmania, L. lineata are associated with stands of Giant Kelp (Macrocystis) (uncited reference, in Edyvane, 2003).

Juveniles are still occasionally seen on shallow reefs, particularly in Tasmania, but are not as abundant as they were prior to heavy fishing of inshore populations (Hutchins and Swainston, 1986; Kuiter, in Gomon et al., 1994). Small juveniles (around 18 cm fork length) have been caught on shallow reefs off south-eastern Tasmania during summer (Murphy and Lyle, 1999, cited by Morton et al., 2005). In southern Tasmania (and other parts of that State), juveniles occur on shallow reefs to about 5m, and tend to remain around shallow reefs for several years, with only limited movement, whereas larger fish move offshore into deep reef areas, and are capable of travelling extremely long distances (Murphy and Lyle, 1999; Tracey and Lyle, 2005, cited by Morton et al., 2005). Offshore movement of older juveniles is supported by data from the commercial fishery which shows fish around 45cm recruiting to the offshore hook fishery (Lyle and Jordan, 1999, cited by Lyle and Hodgson, 2002).

Notes on the Biology

Growth and Age

L. lineata grows to around 1.2m total length (TL) (May and Maxwell, 1986; Lyle, 1995; Hutchins and Swainston, 2001; Fishnet, 2004), but most fish that are caught are smaller (e.g. in the range 50cm – 80cm).

Juveniles reach a mean length of around 28cm after two years and 42cm after four years, with most growth occurring during summer and autumn (Murphy and Lyle, 1999). Growth rates are faster for the first 5 years of life, and length, weight and growth characteristics are similar for males and females during this time (Tracey and Lyle, 2005). Older fish grow significantly more slowly, and there is a large range in size-at-age for fish over approximately 50cm (Lyle and Hodgson, 2002).

During a study in Tasmania, seasonal growth variability was observed over the first five years, with growth rates peaking approximately one month after the observed peak in sea surface temperature (Tracey, 2007).

The size composition of Striped Trumpeter from inshore reefs of south-eastern Tasmania was examined between 1995 and 1997, using 64mm, 89mm, 105mm and 114mm meshes (Murphy and Lyle 1999). All fish caught were juveniles, with fish ranging from 18 to 47cm, and most fish were between 27 and 42cm. During those surveys, the overall size composition was strongly influenced by the size of the meshes used, and by a single cohort (representing the 1993 year class) that grew in size during the period of the study (Lyle and Jordan, 1999).

Some authorities have reported a maximum weight of 25kg for this species (Ruwald et al., 1991; Kuiter, in Gomon et al., 1994; Lyle, 1995, cited by Australia Bureau of Statistics, 1996); however Trumpeter of that size have only very rarely been recorded. Other than a 10.5kg specimen caught off Kiama in NSW in 1993 (Australian Anglers Association, 2005), most Australian fishing records of Tasmanian Trumpeter are of specimens smaller than 10kg. During a study of weight – fecundity relations in Tasmania, an individual of 9.5kg was recorded (Tracey, 2007). Aquafin CRC (2004) reported that the species commonly weighs around 7kg.

The species may live for up to 40 years or more, with a recent maximum age (from otolith readings) of 43 years (Tracey and Lyle, 2005; Tracey, 2007).

Diet

The species is an opportunistic, bentho-pelagic carnivore, and feeds on small invertebrates (molluscs and crustaceans), small benthic and bentho-pelagic fishes, and cephalopods (including squid and octopus) (Paulin et al., 1989; R. Goldsmid, pers. comm., cited by Morton et al., 2005; recreational fishing records). Reported fish species in the diet include Ocean Perch Helicolenus percoides (Bulman et al., 2001, cited by Bruce et al., 2002).

In New Zealand, Halicarcinus crabs and other crustaceans have been recorded in the stomach of Latris lineata (Thompson, 1912).

Reproduction

Previous estimates of size and age at maturity were 44 cm and 5 years of age for females, compared with males at about 53cm or 8 years (Hutchinson, 1993, cited by Lyle and Hodgson, 2002; Morton et al., 2005). More recently, Tracey et al. (2007a) reported a size at 50% maturity of 54.3cm fork length (FL) for females (estimated age = 6.8 years) and 52.9cm FL for males (estimated age = 6.2 years).

Spawning occurs from winter (July) to spring (October), commencing and finishing earlier at lower latitudes (Ruwald et al., 1991; Neira et al., 1998; Lyle and Hodgson, 2001, cited by Morton et al., 2005). In Tasmania, the spawning season occurs in the spring, with peak spawning activity in September and October (Tracey et al., 2007). Most larvae have been caught in coastal waters off western Tasmania from September to October (Neira et al., 1998, cited by Morton et al., 2005).

Striped Trumpeter are multiple spawners, and previous batch fecundity estimates were reported to be 100,000 and 400,000 eggs per batch, for females weighing 3.2kg to 5.2kg respectively (Ruwald et al., 1991, cited by Morton et al., 2005). More recently, Tracey et al. (2007a) reported batch fecundity estimates ranging from 205,054 for a 2 kg fish (540mm FL) to 2,351,029 for a 9.5kg fish (800mm FL). Eggs are small (1.3 mm diameter) and pelagic, with larvae hatching at a size of 2.8 to 3.3 mm (Ruwald et al., 1991; Neira et al., 1998, cited by Morton et al., 2005).

The distribution of larvae, and recruitment processes are largely unstudied. However, the species has a complex early life history, including a long planktonic phase of around nine months offshore (D. Morehead, TAFI, pers. comm., cited by Morton et al., 2005), followed by an inshore juvenile phase (Tracey and Lyle, 2005). Metamorphosis from the post-larval ‘paperfish’ stage probably occurs about nine months after hatching. Small juveniles (around 18 cm fork length) have been caught on shallow reefs off south-eastern Tasmania in January (Murphy and Lyle, 1999, cited by Morton et al., 2005).

There is evidence of marked variation in recruitment in Striped Trumpeter (Murphy and Lyle, 1999). During a study undertaken in the 1990s, a large number of juvenile Striped Trumpeter recruited to inshore rocky reefs in southern Tasmania. The strong cohort was based on the 1993 spawning season, and there was also a relatively large cohort of the 1994 year class. Anecdotal evidence suggests that, prior to this time, very few Striped Trumpeter had recruited to these reefs over the previous two decades (Murphy and Lyle, 1999).

Behaviour

In Tasmania, a tag-recapture study showed that juvenile Striped Trumpeter are predominantly residential rocky reef fish, most recaptures occurring within 5 km of the tagging location, although a small proportion moved between 5km and 30km (Lyle and Jordan, 1999). During that study, the average distance moved tended to increase as the time at liberty increased (Murphy and Lyle, 1999).

Juveniles occur in inshore shallow reef areas for several years, and move offshore as they approach maturity (Lyle and Jordan, 1999; Tracey, 2007). Offshore movement over time has been indicated by tagging data, and is also supported by commercial fishery data, which show fish around 45cm entering the offshore fishery (Lyle and Jordan, 1999).

Migration

Several adult Striped Trumpeter have been recorded moving hundreds of kilometres along Australia’s eastern seaboard. One fish tagged in Tasmania was recorded in New South Wales (Lyle and Hodgson, 2000, cited by Bruce et al., 2002). During 2001, a Striped Trumpeter tagged off the Tasman Peninsula in 1996 was recaptured off St Paul Island (southern Indian Ocean), after travelling a straight line distance of around 5,800 km (Lyle and Murphy, 2001, cited by Morton et al., 2005). A protracted pelagic larval phase and a recent transoceanic tag recapture of an adult fish suggest significant potential for genetic mixing between widely separated populations. However, phylogenetic analysis of mitochondrial DNA control region sequences suggested no genetic mixing between Tasmania, New Zealand and St Paul / Amsterdam Islands, which indicates that there is population structure at a transoceanic scale for this species (Tracey et al., 2007b). DNA sequence analysis indicated that the New Zealand Striped Trumpeter population was genetically distinct from the Tasmanian and St. Paul / Amsterdam Island populations (Tracey, 2007). Further, in a recent study, elliptical Fourier analysis of otolith shape (coupled with multivariate analysis), indicated little to no connectivity between the Striped Trumpeter population of Tasmania and the St. Paul / Amsterdam Island populations (Tracey, 2007).

An analysis of molecular variance coupled with phylogenetic analyses suggested no significant structuring of Striped Trumpeter from three locations around Tasmania, and therefore, there is considered to be a single stock in Tasmania (Tracey, 2007; Tracey et al., 2007b).

Other Information

Latris lineata has been recorded as a minor component of the diet of the Australian fur seal (Arctocephalus pusillus doriferus) (Hume et al., 2004).

Fisheries Information

Commercial - General

Striped Trumpeter is considered to be one of the “best eating” fishes (Edgar, 2000). Hutchins and Swainston (1986, 2001) listed the species as being “excellent eating”, and the Tasmanian Trumpeter is highly prized as a table fish (Lyle, 1995; Australian Bureau of Statistics, 1996). The species is sold through wholesale fish markets such as the Melbourne market, at which 5.9t was sold in 2000; and 12.3t was sold in 1998 (C.H. Smith Marine, 2004).

In most years during the period 1980 to 2000 onwards, the majority of the Australian catch came from Tasmanian waters, with minor proportions of the total from Victoria and South Australia. According to BRS statistics, during the 1990s, the major proportion of the total Australian catch was taken from Tasmanian waters; however during the period 1990 – 1997, between 4% and 36% per annum of the Australian catch was taken in Victorian waters. According to Tasmanian and Victorian fishing return forms, and Commonwealth logbook data (cited in Lyle and Hodgson, 2002): (i) the Tasmanian catch between 1990 and 2000 ranged between 41t and 98t per annum, with catches around 50t – 70t in most of those years; (ii) the Victorian catch was about 37t in each of 1990/91 and 1991/92, and less than 20t per annum during years of the mid 1990s; and (iii) catches from Commonwealth waters ranged between 60t and 111t per annum from 1990 to 2000, and were in the range of 70t – 100t during most of those years.

Commercial – Commonwealth waters

Latris lineata is also taken as bycatch in Commonwealth-managed fisheries, including various components of the Southern and Eastern Scalefish and Shark Fisheries (SESSF) (AFMA, 2002a). Latris lineata is listed as one of 10 main species taken in the scalefish sector of the Gill-net, Hook and Trap fisheries (= South East Non-Trawl and Southern Shark fisheries) component of the SESSF (AFMA, 2001d). During a monitoring program for that fishery, Knuckey et al. (2001) reported that L. lineata was caught both in and out of the Australian Fishing Zone, with an example of the latter being a half tonne catch of Striped Trumpeter in 21 demersal long-line shots (= 43,000 hooks) taken at the Gascoyne Plateau. Trumpeter in the size range 47cm – 84cm were recorded in the Gascoyne Plateau catches (Knuckey et al., 2001). During the GHAT fishery pilot monitoring survey, L. lineata was one of the top 10 species retained in an 8 tonne catch taken in 5 shots off western Tasmania; however numbers were minor compared with catches of Pink Ling (Knuckey et al., 2001). GHAT-endorsed operators take a bycatch of Striped Trumpeter in gill-nets when targeting shark or scalefish (mainly Blue Warehou) on reef areas between approximately 80m - 120m deep (Lyle and Jordan, 1999). In the GHAT fishery, mesh net vessels off eastern Victoria record L. lineata in the catch, when targetting Blue Warehou (Knuckey et al., 2001). Walker et al. (2003) reported that during monitoring of Southern Shark fishery (component of GHAT) catches off Tasmania from 1973 to 1976, an average of 73 (SE = 40) and 22 (SE = 22) Striped Trumpeter were caught using 7-inch and 6 –inch nets respectively, per 1000,000 hook hours (or 1,000 km hours). Although there are no size composition data available for shark net catches, the large mesh size of shark nets (>150mm) tends to select for larger/older Trumpeter (Lyle and Hodgson, 2002). It is noted that in the Southern Shark fishery component of GHAT, along with others in the Commonwealth-managed SESSF, i.e. South East trawl component (SETF) and Great Australian Bight trawl component (GABTF), there is a stated bycatch possession limit of 20kg of L. lineata in S.A. and Victorian State waters, because it is a State-managed species (AFMA, 2002a, 2004e).

The species is part of the by-product of the otter trawl sub-fishery of the SETF and is also reported to be caught incidentally by crew working in this fishery, using hand-lines (Wayte et al., 2004). Striped Trumpeter is also reported to be caught in the GABTF (Ward et al., 2003).

There is a 20kg trip limit for Commonwealth-licensed fishing vessels catching this species in waters of the Commonwealth GAB Trawl sector, off South Australia. There is also a 20kg catch restriction for Commonwealth Scalefish Hook, Shark Hook, Gill-net Sectors and Coastal waters permits, operating off South Australia or Victoria (AFMA, 2004e).

For L. lineata, Pagrus auratus (Pink Snapper) and Seriola lalandi (Yellowtail Kingfish), there is combined possession limit of 250kg for these species in Tasmanian waters, when taken by Commonwealth-licensed vessels.

Commercial – Tasmania

Most of the Australian catch is taken in Tasmania. Striped Trumpeter have been fished commercially in Tasmania since the late 19th century, with almost 5,500 fish reported from the Hobart fish market during 1888 (Lyle and Jordan, 1999). The catch is segregated, because juveniles and adults are predominantly found inshore and offshore respectively. Juveniles are primarily caught using inshore gill-nets (“grab-all” nets) on shallow reefs (5m to 50m, but usually less than 20m) and often with other species, and adults are caught using hook methods (drop-line, hand-line, bottom long-line, trot-line) or large mesh gill-nets (shark nets) on deeper reefs (80 to 300 m) (Lyle and Hodgson, 2002; Morton et al., 2005; Tracey and Lyle, 2005). Catches from Tasmania are taken by State fishers, and also by dual-endorsed fishers, who hold Commonwealth and Tasmanian fishing permits. Hook fishing is undertaken over hard bottom, with drop-lines generally fished in depths of 60-140m and hand-lines between 40-80m and 120-160m (Lyle and Jordan, 1999). Long-line and shark net catches are primarily a by-product of fishing for Gummy Shark (and previously School Shark), but the quantities taken are lower (e.g. 18-25% of the catch per annum between 1995/95 and 2000/01) compared with other methods (Lyle and Hodgson 2002). GHAT-endorsed operators account for a large portion of the offshore net catch by targeting sharks and scalefish (primarily Blue Warehou), on deep reef areas off Tasmania (Lyle and Jordan, 1999) (see Commercial – Commonwealth waters). During the mid-late 1990s, drop-lines accounted for about 30% of the catch per annum, followed by hand-lines (20-25%), grab-all nets (20%) and shark nets (10% - 15%); catches by other methods were minor (shark long-lines, rock lobster pots, trot-lines, bottom long-lines and fish traps) (Lyle and Jordan, 1999). A catch summary over time is provided below. During the 1960s and 1970s catches were reportedly low, mostly under 5t per annum (BRS, 2004; Morton et al., 2005), although this may reflect the misreporting of fish as Bastard Trumpeter (Lyle and Jordan, 1999). During the early 1980s catches increased rapidly, to reach about 30t per annum during the mid 1980s and 70-80t per annum during the late 1980s and early 1990s (Lyle and Jordan, 19991; Smith and Heran, 2001).

In 1990 and 1991, catches were reportedly greater than 70 tonnes (Australian Bureau of Statistics, 1996). The total catch in 1990/91, including catches taken by Victorian and Tasmanian vessels from Tasmanian waters, was reported to be 111.6 tonnes (Lyle and Jordan, 1999). Although reporting was not gear-specific prior to the 1990s, it is assuming that over 75% of the total catch in each year was taken on hooks (Lyle, 1994b). Most of the remainder was taken by gill-net, and in 1989, gill-nets accounted for 60% total catch. Catches throughout the mid-1990s remained between 60t and 80t per annum, reaching a high of almost 100t at the turn of the century, and then declined to less than 50t during the early 2000s. Limited ageing of catch samples has indicated that the increase in catches during the latter half of the 1990s reflected the impact of strong 1993 and 1994 cohorts as they moved through the fishery (Morton et al., 2005). The hook and trap sector of the Tasmanian Inshore Scalefish Fishery typically accounted for 70% of the catch during the 1990s, and the gill-net sector took a further 20% of the catch during that period (Lyle, 1995; Australian Bureau of Statistics, 1996; Lyle and Jordan, 1999). Similarly, in 2000, 70% of the catch was reported to have been taken by line-fishing (McLeay et al., 2002). In 2000/01 hand-line and drop-line methods together accounted for around 55% of the annual catch. In that year, around 11% of the catch was caught by long-line and in shark nets, primarily as a by-product of fishing for sharks (Lyle and Hodgson, 2001). The catch in 2002 was close to 30t, and the reported catch in 2002/03 was about 35 tonnes (Morton et al., 2005). Although Tasmanian Trumpeter is taken commercially all around Tasmania, about 80% of the catch is taken from continental shelf grounds on the north-east, east and south-east coast, and Flinders Island. Smaller catches are taken from the north-west, west, south and south-west. Most catches occur in summer and autumn, and most fish caught are between 50cm and 70cm, well over the legal limit of 33cm. In Tasmania, limited catch sampling of the hook catch of Striped Trumpeter showed that fish ranged from 42 to 85cm, with the majority of the catch between 50 and 70 cm (Lyle and Jordan, 1999) Striped Trumpeter enter the offshore hook fishery at around 45cm, at an age of around 5-6 years. As growth slows considerably around this age, the dominant 50-70cm size class represents fish over a broad range of ages (Lyle and Jordan 1999). Occasionally individuals are caught over 80cm in length, and have been measured at up to 120cm in length, and 25kg in weight (Lyle, 1995; Australian Bureau of Statistics, 1996).

In Tasmania, Striped Trumpeter is a bycatch species in the inshore gill-net fishery for Banded Morwong (Murphy and Lyle, 1999). Striped Trumpeter is also reported to be a considerable bycatch when fishers target Ocean Perch and Jackass Morwong offshore (Lyle and Jordan, 1999).

There is also a minor by-catch of Striped Trumpeter in rock lobster pots (Lyle and Hodgson, 2001).

Striped Trumpeter: Reported Catch from Tasmania, 1969-2005

(from Lyle and Jordan, 1999; Lyle and Hodgson, 2002; Lyle et al., 2004; Ziegler et al., 2006)

Commercial – Victoria

BRR (1991) reported occasional catches of this species during the mid 1980s, in the order of several tonnes per annum. The fishery for Striped Trumpeter in Victoria is small; for example catches were less than 5 tonnes per annum during the late 1980s and early 1990s (Stewart et al. 1991, cited by Lyle and Jordan, 1999).

There are records of the species being taken by commercial fishing in the outer Port Phillip Bay / Bass Strait region (Anonymous, 2002b, cited in Froese and Pauly, 2009).

Commercial – South Australia

The fishery for Striped Trumpeter in South Australia is small. BRR (1991) reported catches of “Striped Trumpeter L. lineata” from South Australia in the order of 1t to 5t per annum in most years between 1978 and 1990 (1990 being the limit of statistics reported in that reference), and higher catches in 1979/80 (6.5t) and 1984/85 (10.2t). However, it is possible that the catches in South Australia might have referred to another species (BRS representative, pers. comm., 2006). Catches were reported to be less than 5 tonnes per annum during the late 1980s and early 1990s (Stewart et al. 1991, cited by Lyle and Jordan, 1999). There is no species code for Latris lineata in the South Australian marine scalefish fishery, and it is not known for this report whether catches of this species have been pooled with those for Bastard Trumpeter (L. forsteri).

Commercial – New South Wales

During 2000/01, the total commercial catch of trumpeters (Latris lineata and Latridopsis forsteri combined) in NSW was reported to be about 11 tonnes, with 25% of this taken by the NSW Ocean Trawl Fishery (see below) (NSW Department of Primary Industries, 2004).

Trumpeters (reported to be Latris lineata and Latridopsis forsteri) are recorded in the bycatch of the NSW Ocean Trawl Fishery (NSW Department of Primary Industries, 2004). For example, in the ocean fish trawl sector of that fishery, a combined catch of 2.6 tonnes of trumpeters was recorded in 2000/01, but only 65kg was taken in the ocean prawn trawl sector.

Striped Trumpeter is part of the bycatch in the NSW lobster fishery (New South Wales Fisheries, 2004c). During bycatch observer studies from 1999/2000 to 2001/2002, a total of 298 specimens (= 619kg) of Tasmania Trumpeter were caught and retained, with none discarded (data by Liggins et al., cited by New South Wales Fisheries, 2004c).

Recreational

The species is taken by recreational anglers (Lyle, 1995; Australian Bureau of Statistics, 1996) and in sports fishing competitions (e.g. Australian National Sportsfishing Association). Some fishing associations keep records of the maximum sizes caught (e.g. record of 8.54kg, from Port Fairy in 1991: Australian Anglers Association - Victorian Division, 2003).

Striped Trumpeter is an “iconic” species in Tasmania, and there is inter-sector competition for these fish between commercial and recreational fisheries (Morton et al., 2005). Striped Trumpeter is highly esteemed by both line and gill-net fishers (Morton et al., 2005).

In Tasmania, this species is heavily targeted by recreational fishers in deep water. Striped Trumpeter are commonly caught by anglers fishing off Flinders Island, and along the north-east and east coast of Tasmania (Fishnet, 2004). More recently, this species has been targeted along the Tasmanian south coast, off Pedra Branca (G. Edgar, TAFI, pers. comm., 2009).

This species is reported to be increasingly targeted by recreational fishers in Tasmania (Tracey, 2007). Preliminary estimates of the 1997 recreational gill-net catch indicated a catch of almost 12 tonnes, which compares with a commercial grab-all net catch of around 18 tonnes for the same period (Lyle and Campbell, 1998). The size of the recreational hook catch is unknown, though it is clear that fishers target the species on shallow- as well as deep-water reefs. During the mid 1990s, a strong year class of juvenile Striped Trumpeter was relatively abundant in inshore waters (Murphy and Lyle 1999), and recreational anglers are known to target juveniles in shallow waters along with Bastard Trumpeter (Lyle and Campbell 1998). There are charter boat companies in some locations (e.g. off St Helens) that target Striped Trumpeter in deeper waters, and the reefs where schools of this species aggregate to feed are known within the offshore fishing community, who use echo sounders to locate the exact reefs (e.g. off the east and north-east coast, as far seaward as the continental shelf drop-off).

The National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003; Morton et al., 2005) reported that, during the survey time period (May 2000 to April 2001), approximately 17,000 Striped Trumpeter specimens were caught and kept by recreational fishers in Tasmania, out of a total catch of approximately 18,000. During the 2000/01 survey period, almost all of the catch was taken by boat fishers, and about 70% of the catch was taken using lines with bait, and 25% using gill-nets. Set-lines accounted for 8% of the total catch, reflecting the practice of fishing with drop-lines over the deeper reefs. About 35% of the retained catch was taken from south-east Tasmania (Tasman Peninsula); 43% from the central east coast; about 9% from off the eastern north coast; 5% from the north-east coast, and 5% from the Derwent Channel (Morton et al., 2005). Some size composition studies of the recreational catch in Tasmania have been undertaken. For example, during surveys in 1997/98, the size range was 33 to 82cm fork length (FL), with modes between 40-45cm and around 60cm (Lyle and Campbell, 1999). During surveys in 2000/01, the few Striped Trumpeter that were examined ranged between 38-63cm with an average size of 52cm (Lyle et al., 2002). Fish caught by grab-all net were more restricted in size than line-caught fish, ranging between 34-62 cm, with an average of 48cm and 1.7 kg. Line-caught fish were slightly larger, averaging 52cm and 2.2kg (Morton et al., 2005).

The recent National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) reported that, during the survey time period (May 2000 to April 2001), 1,031 Striped Trumpeter specimens were caught and kept by recreational fishers in New South Wales.

The Australian Underwater Federation has reported that the record size of L. lineata taken by spearfishing was 2.041kg, being a specimen taken from Queenscliff in Victoria (Australian Underwater Federation, Inc., 2003).

Aquaculture

During the past two decades, Striped Trumpeter has been cultured in aquaculture operations, as a potential food fish. Striped Trumpeter brood stock, collected from the wild, are spawned in hatcheries using temperature and photoperiod control. The species has been successfully spawned in this artificial environment, and in recent years juveniles have subsequently been reared. The Department of Primary Industries, Parks, Water and Environment (DPIPWE, formerly DPIWE), and the Tasmanian Aquaculture and Fisheries Institute (TAFI, University of Tasmania) are involved with ongoing research and development of cultured Striped Trumpeter. Examples of the large research effort into the aquaculture of Latris lineata include the work of Bermudes and Ritar (1999); Morehead et al. (1998, 1999, 2000a, 2000b, 2001); Morehead and Hart (2003); Cobcroft and Pankhurst (2003); Cobcroft et al. (2001a, 2001b); Trotter (2003); Trotter et al. (2001, 2003a, 2003b); Bransden et al. (2003, 2004, 2005); Morehead et al. (2004); Brown et al. (2005); Battaglene and Morehead (2006); Battaglene and Cobcroft (2007); Andrews et al. (2007); Cobcroft and Battaglene (2009), and Morehead et al. (2009). In 2007, a post-larval rearing nursery room was established at Tasmanian Aquaculture and Fisheries Institute, for holding commercial batches of Striped Trumpeter larvae, from 90 to approximately 270 days old. In 2007, approximately 12,000 juvenile fish were produced (DPIW Tasmania, 2009). Since then, several groups of hatchery-produced Striped Trumpeter have been transported and stocked into sea cages in the Huon River. During the late 2000s, research was being undertaken in Tasmania to assess the optimum size of fish and time for releasing cultured Striped Trumpeter into sea cages.

Vulnerable Characteristics of the Species

Tasmanian Trumpeter is a relatively large, long-lived, site-associated fish species found in reef habitats, and species with such population dynamics and habits are vulnerable to decline from over-exploitation.

Juveniles are strongly site-associated with inshore reefs, and because this species is highly prized as a food fish by both commercial and recreational fishers, and is easily found and caught, it is therefore vulnerable to over-exploitation (including growth-overfishing).

The Tasmanian Trumpeter is reported to have a very low resilience to exploitation, in terms of minimum population doubling time (based on age, growth and reproductive parameters) (Froese and Pauly, 2009), and high to very high vulnerability to fishing-induced population decline (Cheung et al., 2005, cited in Froese and Pauly, 2009).

This species matures at a large size (more than 50cm), and the minimum legal size Tasmania is lower than the size at first maturity, and a proportion of fish being caught have not had the opportunity to spawn. In other parts of south-eastern Australia there are no minimum size limits, and the proportion of reproductively immature fish that is taken has not been determined.

Previous commercial and research catch sampling has indicated marked recruitment variability in this species (Lyle and Hodgson, 2002). For example, prior to a strong 1993 year class (and, to a lesser extent, the 1994 year class), anecdotal evidence suggests that very few Striped Trumpeter had recruited to inshore reefs for at least 20 years. There is also little evidence of older year-classes in inshore waters (Lyle and Jordan, 1999). As part of this strong recruitment variability from year to year, there are long periods (e.g. up to decadal scales) of poor recruitment, which increases the susceptibility of populations to gradual decline if fishing remains high during years of poor recruitment.

South Australia is at the edge of the geographic range of this species, and the species is found in comparatively low abundance in South Australia, compared with the eastern part of the range.

Threatening Processes

Fishing is one of the main threatening processes, especially in the main part of the species’ range in southern Australia (e.g. Tasmania). Previously, the species was among the most commonly caught fishes around Tasmania, but heavy fishing during the past 50 years is reported to have virtually eliminated inshore populations (Hutchins and Swainston, 1986; Edgar, 2000). During the 1990s and 2000s, stock levels in Tasmanian waters were not known, but concern was expressed about the localised depletions that may be occurring, due to the effects of fishing, coupled with apparent poor recruitment in recent years (Lyle et al., 2004). Reportedly of particular concern is the inshore gill-net harvest of Striped Trumpeter, because this sector has potential to take large numbers of immature fish, especially when large recruitment pulses are evident (Morton et al., 2005).

Catch data in Tasmania, including catches reported in Victorian and Commonwealth logbooks, but taken in waters south of latitude 39° 12’S (i.e. waters incorporated in a OCS agreement for Striped Trumpeter), showed that the 2000/01 commercial catch of 50 tonnes was equivalent to 50% of that taken in the previous year, and was the lowest since 1990/91 (Lyle and Hodgson, 2002). As another example, compared with the 1990s, during the 2000s in the shark fishing sector, there was an increased proportion of small catches of Striped Trumpeter (e.g. < 50kg) and a lower occurrence of large catches, and this was observed in both shark net and shark long-line bycatch, and this may indicate a reduced abundance of large / older fish offshore (Lyle and Hodgson, 2002). In Tasmania, during the early 2000s, it was uncertain what effect the current 250kg trip limit (see Management Notes) had on effort and catches, compared with other factors. It was uncertain whether the decline in catches represented a true decline in abundance (due to a combination of factors, including poor recruitment levels into the fishery at that time; reduced biomass of new recruits and adults; and also excessive fishing mortality level), or was a result of management changes influencing target fishing practices (e.g. Lyle and Hodgson, 2002). However, catch and effort data for major methods used in the fishery indicate that the declining trend was already evident prior to the trip limit introduction (Lyle and Hodgson, 2002). There is concern that unless fishing mortality decreases over time, the stock in Tasmania may be recruitment-overfished (e.g. Lyle and Hodgson, 2002).

Strong recruitment variability could result in marked variations in population size, especially if there is a prolonged period of poor recruitment, with the fishery becoming dependent upon relatively few year classes. If, as implied by the recent catch data in Tasmania, there has been poor recruitment and the abundance of the mature stock has declined significantly, then catches are likely to remain depressed until there is a period of sustained good recruitment (Lyle and Hodgson 2002). In cases of prolonged periods of poor recruitment, effort should be reduced.

Management is hindered by the multi-sector and multi-gear nature of the catches, and the fact that this species is taken as a target species in some fisheries, and as by-catch in others.

In a draft ecological risk assessment for species in the South East Trawl component of the Southern and Eastern Scalefish and Shark fisheries (SESSF), Striped Trumpeter was reported to be at “high risk” of population impacts from operation of the otter trawl sub-fishery of the South East trawl fishery (Wayte et al., 2004). In a similar risk assessment for species in the Gillnet, Hook and Trap component of the SESSF, Webb et al. (2004), reported L. lineata to be at “medium risk” of impacts from operation of the southern shark gill-net, southern shark demersal long-line, scalefish demersal long-line and scalefish automatic long-line sectors.

Reduction in the geographic extent and density of Giant Kelp in Tasmania (see Edyvane, 2003) may have implications for populations of this species, in areas where Tasmanian Trumpeter are associated with kelp.

In New Zealand, catches have continued to fall during the past decade, with landings in some areas being below the allowable catch under quota (e.g. see NZ Ministry of Fisheries, 2004h). It is recognised that localised populations can be quickly “fished out”, and fishing is considered to be the main threat to Striped Trumpeter populations in New Zealand (Weeber and Szabo, 2004, 2005).

Another major threatening process for this species may be climate change. Striped Trumpeter is a cool water species, adversely affected by rising water temperatures. It is currently uncertain to what extent the historic decline in the Tasmanian populations is due to rising water temperatures, comparing with over-fishing (G. Edgar, TAFI, pers. comm., 2009).

Research Notes

In Tasmania, PhD research has been undertaken on the biology and population dynamics of Striped Trumpeter, and the stock viability has been assessed (according to available data, which is considered to be limited) (Tracey, 2007). This project included research on the reproductive biology of Striped Trumpeter (Tracey et al., 2007a), and also on the genetics and stock structure of populations in Tasmania, New Zealand and St Paul and Amsterdam Islands, using both molecular techniques and otolith morphometrics (Tracey et al., 2007b). In relation to the latter, research was undertaken on the use of Fourier waveform analysis (analysis of size and shape) to categorise Striped Trumpeter otoliths, in order to determine population identity of samples from different geographical areas. This form of shape analysis can be used in conjunction with constrained non-parametric statistical tests as a tool for stock discrimination (Tracey et al., 2006). During the Tasmanian study, recruitment processes were investigated, based on otolith microchemistry and modelling of larval dispersal (Tracey 2007).

In Tasmania, an integrated bio-physical larval dispersal model was developed in an attempt to explain the high degree of inter-annual recruitment variability displayed by Striped Trumpeter. The model utilised information on reproductive biology, ontogenetic habitat preferences and stock structuring, as well as additional information on larval biology from aquaculture trials (Tracey, 2007). Although the model was unable to accurately predict observed inter-annual recruitment variability, it provided insights into source and settlement regions, as well as the importance of the addition of biological components, such as timing of spawning, growth and mortality (Tracey, 2007).

The information that was collated for the PhD project cited above may assist the development of spatial fisheries management measures (Tracey, 2007).

Research Recommendations

Although there has been a recent research project on Striped Trumpeter (see recent references by Tracey, cited above), there remains a lack of information on the wild population, including population size and movements over space and time (particularly migration from inshore to offshore reefs); age composition and extent of movement of fish in deeper water; spawning locations and distribution of larvae; representative sampling of commercial catches to determine changes in size and/or age composition; and an index of juvenile abundance (e.g. through standardised pre-recruit surveys) (Lyle, 1995, cited by Australian Bureau of Statistics, 1996; Lyle and Jordan, 1999; Lyle and Hodgson, 2002). Assessment of fishery sustainability will be assisted by this information (Lyle and Jordan, 1999).

In Tasmania, the Scalefish Fishery Research Advisory Group considered research priorities to be recruitment variability, gear interactions and stock assessment, the latter including characterisation of the commercial fishery in terms of size composition and age-structure of the catch across methods, and across the geographic range of the fishery (both inshore and offshore) (Lyle and Hodgson, 2002).

In Tasmania, size and age composition data are needed for the offshore component of the fishery in order to determine appropriate catch strategies. Also, the relation between recruitment strength to inshore reefs, and the subsequent relative abundance on offshore reefs after migration needs to be determined (Lyle and Jordan, 1999).

Determinants of recruitment variability are not known, but may be related to oceanographic processes occurring during the long larval phase (Bruce et al., 2002). Research into the relationship between recruitment strength and oceanographic variables may aid understanding (and prediction) of relative abundance levels over space and time.

Population size of Striped Trumpeter is unknown in most areas of southern Australia. The relation between populations in Tasmania and other south-eastern Australian States should be determined if possible, particularly in relation to offshore migration with size / age.

The species identity of trumpeter catches outside of the AFZ (reported as L. lineata – see Knuckey et al., 2001) should also be ascertained, and the relation between this stock and south-eastern Australian stocks should be determined.

Management Notes

In south-eastern Australia (particularly Tasmania), management of the fishery is complicated by the multi-gear, multi-sector nature of the fishery, and fact that this is both a target and non-target species for commercial fishers, and is also highly valued (and caught in large numbers) by the recreational sector.

In Tasmania, responsibility for the management of Striped Trumpeter in both inshore and offshore waters (from 3 – 200 nautical miles) was given to that State in 1996 through an Offshore Constitutional Settlement (OCS) arrangement with the Commonwealth. A Memorandum of Understanding accompanied the OCS, and specified trip limits for Commonwealth-licensed fishers of 100kg for South East Non-Trawl (SENT) permit holders (= Gillnet Hook and Trap component of the SESSF) and 20kg for all other permit holders (Lyle and Hodgson, 2002). In Tasmania, when the Tasmanian scalefish fishery management plan was implemented in 1998, gear restrictions were introduced for all commercial scalefish fishers operating in State waters. However, after the introduction of the management plan those fishers who held both a Tasmanian scalefish licence and a Commonwealth permit to fish in the Southern Shark or South East Non-trawl (i.e. GHAT) fisheries were effectively allowed to target unrestricted quantities of Striped Trumpeter in offshore waters using their Commonwealth gear allocations (i.e. a significant change to the original 20kg and 100kg restrictions). In addition, Tasmanian rock lobster fishers were also allowed to target unrestricted quantities of Striped Trumpeter in offshore waters using their State scalefish gear allocations. In response to this uncontrolled targetting, since 2000 there has been a 250kg limit to the amount of L. lineata that can be taken by commercial fishing licence holders (or holders of appropriate authority) in State waters, and the limit applies to both Commonwealth and State licensed fishers (Lyle and Hodgson, 2002; Office of Parliamentary Counsel, 2004). This measure was introduced because it was recognised that Striped Trumpeter fishing was seasonal, as part of a diverse fishery, unable to sustain continuous targeting, and therefore required some protection against over-fishing. Also, the introduction of quotas for key species in the Gillnet, Hook and Trap component (South East Non-trawl) component of the SESSF, as well as rock lobster, plus impending output control management of the Southern Shark fishery component, meant that Striped Trumpeter may have been vulnerable to additional targeting by operators participating in those fisheries (Lyle and Hodgson, 2002).

In Tasmania, there are targets for size/age composition (of commercial catch, and also pre-recruit year classes, based on monitoring), catch, effort and CPUE targets, and management action is triggered if values fall outside reference limits (e.g. Lyle and Hodgson, 2002).

In Tasmania, the minimum size limit for Tasmanian Trumpeter was previously 33cm TL, then changed to 35cm TL during the 1990s, and increased again to 45cm TL from 2004 onwards, as part of the changes to the recreational fishery from the 2004 review Scalefish Fishery Management Plan (Morton et al., 2005). It was recognised that the previous minimum sizes of 33cm, then 35cm, were still significantly smaller than the size at maturity for both males and females of this species (Lyle and Hodgson, 2002).

In Tasmania, there is a personal possession limit of 8 Striped Trumpeter (DPIWE web site, January 2005; DPIPWE web site, August, 2009).

In Tasmania, yield-per-recruit and spawning biomass-per-recruit analyses have been undertaken to assist management targets for the fishery (Tracey et al., 2007a). Results indicated that at the current minimum legal size limit of 450cm TL, yield-per-recruit was estimated to be close to maximum, and spawning biomass-per-recruit (SPR) ranged from 35 to 52% of virgin stock, depending on the mortality estimates used. Although the calculated SPR may be at a level considered sustainable, the method did not incorporate temporal variability, specifically recruitment variability. Therefore, conservative management measures have been recommended until a dynamic model that better describes the population and fishery is applied (Tracey et al., 2007a).

In Tasmania, there is a closed season on fishing for Striped Trumpeter. For example, all recreational and commercial fishing for Striped Trumpeter was closed from 1st September to 31st October 2009 inclusive, as an interim measure to protect this valuable species during part of the spawning period (DPIW web site, August 2009).

Fisheries management in Tasmania discourages the use of highly valued species such as trumpeter for bait. For example, only the heads and frames of Striped Trumpeter may legally be used for baiting rock lobster pots and rings, unless a receipt for purchasing the fish is available (DPIPWE web site, 2009).

In the Commonwealth-managed GHAT fishery, there are several gear specific area closures, and gill-nets are not permitted to be set deeper than 200m south of 41°S, due to the selectivity of gill-nets and their ability to target State-managed species such as Striped Trumpeter (Webb et al., 2004).

Trumpeter species are reported to be at low risk of population impacts from the operation of the New South Wales Ocean trawl fishery (N.S.W. Department of Primary Industries, 2004).

Management Recommendations

Legal minimum sizes (near or above the size at first maturity) should be in place in all States in which this species is caught commercially and recreationally.

Measures to reduce the inshore catch of reproductively immature individuals (e.g. by gill-nets in Tasmania) should be introduced.

Trends in catch and CPUE are influenced by periodic years of strong recruitment (e.g. the 1993 and 1994 year-classes, in Tasmania), and subsequent years of poor recruitment, which can be prolonged (Lyle and Jordan, 1999) Commercial and recreational fishing effort and permissible catch levels must account for the naturally variable abundance of this species, because it is unlikely that continually high effort levels (and catches) can be sustained.

Management of both Commonwealth- and State-managed fisheries should work cooperatively to manage fishing for this species, given the overlap in distribution of the stock between fisheries of the separate jurisdictions, particularly off Tasmania, Bass Strait and Victoria. Also, catches of Striped Trumpeter both within and outside of the Australian Fishing Zone should be monitored closely, given the ability of vessels outside of the AFZ to catch large quantities of trumpeter whilst targetting other species (see also Research Recommendations).

Other Information

The inter-annual differences in the total annual catches of “Tasmanian Trumpeter” reportedly illustrate quasi-decadal variability, superimposed on a long-term downward trend (Thresher, 2002). This pattern may be linked to variability in the strong circum-Antarctic zonal west winds (ZWW) over the latitude range of 35 to 60°S. Variation in the winds (which have a marked quasi-decadal component) is linked to Antarctic (e.g. polar ice) and low-latitude climate (e.g. El Niño-southern oscillation) parameters (Thresher, 2002).

A closely related and newly described species, the Silver Trumpeter, L. pacifica, has recently been discovered on sea mounts in the South Pacific (Roberts, 2003).