© 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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Forster’s  / Long-Snouted / Sharp-Nose / Longnose Weedfish

Family Name:	Clinidae
Scientific Name:	Heteroclinus tristis (previously H. forsteri) (Klunzinger, 1872)
Recommended Status in S.A:	Data Deficient
Rationale:  Forster’s Weedfish is included here because (i) the species is strongly site-associated in nearshore habitats, and is likely found over a narrow depth range, and may thus be vulnerable to habitat impacts in some areas; (ii) Clinids reproduce at a small, site-associated scale (and have live young), characteristics that may increase the species vulnerability to population decline; and (iv) there is no knowledge of population sizes within the range (including in South Australia), and very little is known of the biology and population dynamics.

Page Contents

Current Conservation Status

No listings known

Distribution

Southern Australia

Inhabits Australia’s south-eastern and southern coast, and is most abundant in Tasmania. It occurs in southern N.S.W., Victoria, Tasmania, South Australia, and as far west as Recherche Archipelago in southern WA (Hutchins and Swainston, 1986; B. Hutchins, W.A. Museum, pers. comm., 2006).
The species is considered to be common on nearshore reefs in Victoria (Edmunds and Hart, 2003).

South Australia

In South Australia, there are museum records (of H. forsteri and H. tristis collectively) and survey records, from south-western Spencer Gulf (e.g. several specimens from Peake Bay area); Marion Bay, Edithburgh and other locations along the “heel” of Yorke Peninsula; the metropolitan coast (Glenelg) (2 old records, from 1905); Fleurieu Peninsula (e.g. Aldinga Reef); northern and north-eastern Kangaroo Island (the latter including the Hog Bay area); Port Elliot and Victor Harbor (Encounter Bay region); and Goolwa, at the mouth of the River Murray (an old record from 1916) (Hoese et al., in Gomon et al., 1994; K. Smith, unpubl. data, 2002; Edgar et al., 2006; A. Brown, unpubl. data, 2006; S.A. Museum records, Museum of Victoria records, cited in OZCAM, 2008; photo by A. King, cited in Baker et al., 2008a).
The River Murray mouth is the type locality (Eschmeyer, 2001).

Habitat

The species occurs in “shallow reef and weed areas”, and is considered “very common” amongst large seaweeds on moderately exposed south-eastern reefs, to around 10m depth, and only occasionally seen due to good camouflage (Kuiter, 1993; Edgar, 2000). Kuiter (1993; 1996b) reported the habitat as being “shallow, low reef on sand, with sparse tall weeds, in seagrass areas”.
At one site on the Yorke Peninsula in S.A., the species has been recorded in the shallow subtidal (1m), in a patchy habitat of mixed Sargassum macroalgae, interspersed with Zostera seagrass (A. Brown, unpubl. data, 2006).
Juveniles are cryptic, in marine vegetation; adults are often seen along reef margins, hunting prey (Kuiter, 1996a).
Using Whitfield’s (1999) classification, Higham et al. (2002) described H. tristis as a “marine straggler”, indicating that a small proportion of the population uses estuaries, but most are found in marine waters.
Examples of other habitats in which the species has been recorded include (i) Zostera / Heterozostera tasmanica seagrass beds in Victoria (Hindell et al., 2000), (ii) Posidonia australis seagrass in northern and north-eastern Tasmania (Jordan et al., 1998), and (iii) drift macroalgae (Gracilaria verrucosa) adjacent to a Posidonia seagrass bed, in N.S.W. (Langtry and Jacoby, 1996); and nearshore reef on the north-eastern Tasmanian coast (Barrett and Wilcox, 2001).

Notes on the Biology

Growth

H. tristis grows to around 30cm (Hoese et al., in Gomon et al., 1994; Kuiter, 1996b).
No estimates of longevity were found for this report; however, it is noted that post-settlement growth is rapid, and a study of 12 weedfish species in south-eastern Australia showed that most of the reproductive populations consist of fishes in the 1 + year-class (Gunn and Thresher, 1991).

Diet

The species eats “weed shrimps” (Kuiter, 1996b).
Heteroclinus weedfish are part of the diet of piscivorous fishes such as Yank Flathead Platycephalus speculator (Hindell et al., 2000).

Reproduction

Temperate weedfishes are viviparous, many are “super-foetate” (simultaneously developing multiple batches of eggs and/or embryo) and reproduce over several months in spring and summer (Gunn and Thresher, 1991). Maternal investment in the nutrition of the young is high. After parturition, the larvae spend from 3 to 7 weeks in the plankton, primarily in in-shore waters (Gunn and Thresher, 1991).

Fisheries Information

H. tristis is collected in Tasmania for the aquarium industry. The permitted annual catch limit is 150 individuals, with a fishing block limit (6 x 6 nautical miles) of 25 individuals (DPIWE Tasmania, 2005b; Australian Government DEH, 2005b).

Vulnerable Characteristics of the Species and Threatening Processes

Members of the Clinidae are strongly site-associated in coastal areas of seagrass and macroalgae, and processes which damage such habitats may adversely affect populations.
Members of the family are viviparous (bear live young), and therefore reproduce at a local, site-associated level, and have low dispersive ability, characteristics that can increase vulnerability to processes causing population decline.
The estuarine association (if verifiable) of some H. tristis could render that portion of the population vulnerable to impacts, such as degradation of estuarine water quality and quantity, including severe reduction in estuarine flows.

Research Requirements

As indicated in the section above, very little is known of the biology and population dynamics of this species. Information on the distribution, relative abundance, habitat requirements and biology may help in better determining the susceptibility of weedfishes to threats such as habitat degradation. However, the difficulty of determining distribution and relative abundance of small, cryptic, benthic species such as weedfishes is noted.

Management Requirements

H. tristis is site-associated in nearshore macroalgae and seagrass habitats. Habitat protection is required from processes that result in physical removal of coastal marine vegetation, or degrade the quality of such habitat (e.g. though impacts of eutrophication, siltation etc).
Protection and restoration of estuarine habitats may benefit some populations of H. tristis population, if the species does occur in such areas.

Other Information

The species occurs in a number of marine protected areas in Victoria, such as Wilsons Promontory, Port Phillip Heads and Bunurong Marine National Parks (Edmunds et al., 2003; Plummer et al., 2003). The species has also been recorded at a small number of areas in northern Tasmania, proposed as marine reserves (Barrett and Wilcox, 2001).

Support for S.A. Listing:

Barry Hutchins (ex-West Australian Museum), who recommended Data Deficient category.