© 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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Senator Wrasse

(c) D. Muirhead, MLSSA

Family Name:	Labridae
Scientific Name:	Pictilabrus laticlavius (Richardson, 1840)
Recommended Status in S.A:	Data Deficient
Rationale:  Although Senator Wrasse has a broad geographic range, it is included here because (i) it is a site-associated Labrid, and members of the family are intrinsically vulnerable to over-exploitation, imbalances in population structure, and population decline, due to their accessibility on nearshore reefs, and their demography / life history characteristics (including relatively long life span, and protogynous hermaphroditism); (ii) it occurs over a relatively narrow depth range in nearshore habitats (especially macroalgae-dominated reefs), which, in some areas, are subject to processes that reduce habitat quality; (iii) it is an inquisitive species, which increases its vulnerability to spear-fishing; (iv) it is caught in a number of commercial and recreational fisheries across the range. The status of Senator Wrasse in S.A. cannot easily be determined due to lack of data on population sizes around the State; lack of data on the biology (e.g. growth, age, reproduction) and life history characteristics of the species; and lack of data of the extent and specific impacts of commercial and recreational fishing, and other threatening processes, over space and time.

Page Contents

Current Conservation Status

No listings known

Distribution

Southern Australia

Senator Wrasse is found across the southern half of Australia, between northern N.S.W. and central W.A., including Victoria, S.A. and all around Tasmania (Russell, 1988, cited in Froese and Pauly, 2005; Australian Museum, 2002b).
Senator Wrasse is reported to be the second most abundant wrasse on reefs in Victoria (Edmunds et al., 2000, cited by Edmunds et al., 2004).

South Australia

Senator Wrasse is widespread in S.A., with museum and survey records ranging from Encounter Bay / upper South-East through to the Great Australian Bight.
Examples of locations where it has been recorded include the coast and islands in and around Encounter Bay; parts of the lower Fleurieu Peninsula; the northern, central and southern metropolitan coast of Gulf St Vincent; shallow reefs off north-western, northern, north-eastern, eastern and southern Kangaroo I. (N.B. the species has been recorded in relatively high abundance at a number of sites on the northern side of the Dudley Peninsula); coastal reefs and islands off the western “toe” of Yorke Peninsula / western Investigator Strait (including coastal reefs off Innes National Park, and Chinaman’s Hat I., Haystack I., the Althorpe group and the Western Is.); south-western Gulf St Vincent and eastern Investigator Strait; mid-eastern Spencer Gulf; south-western Spencer Gulf; southern Eyre Peninsula (eastern and western sides); western Eyre Peninsula / eastern Great Australian Bight coast; Investigator group of islands and Nuyts Archipelago (Kuiter, 1983; Branden et al., 1986; K. Branden and S. Shepherd, unpublished data, 1987; Branden et al., 1994; MLSSA, 1997; Muirhead, 1998e; S. Shepherd, unpublished data, 2002-2005; S. Shepherd, J. Brook, K. Brown, A. Brown, and D. Ashcroft, unpublished data, 2002; S. Shepherd and J. Baker, unpublished data, 2002; Fairhead et al., 2002b; S. Shepherd, J. Baker, J. Brook, A. Brown, J. Murrie and K. Smith, unpublished data, 2002; Shepherd and Brook, 2003b; S. Shepherd, A. Brown, J. Brook, and K. Brown, unpublished data, 2003; S. Shepherd, K. Smith, J. Brook, A. Bloomfield, J. Scott, and B. Parkhurst, unpublished data, 2004; S. Shepherd, T. Laperousaz, and D. Muirhead, unpublished data, 2003; Australian Anglers Association, 2005; Shepherd et al., 2005; Reynolds, 2003b, 2005; Edgar et al., 2006; Australian Museum, Museum of Victoria and S.A. Museum records, cited in OZCAM database, 2006).

Habitat

The species is found in waters to about 40m deep (Russell, 1988, cited in Froese and Pauly, 2005).
The Senator Wrasse is usually found on rocky reefs (Australian Museum, 2002b), particularly those covered with Macrocystis or Ecklonia kelp, and/or and other large brown macroalgae (e.g. Phyllospora, Durvillea, Lessonia, Sargassum, Cystophora). It is noted that a study in Tasmania has shown that the species does not emigrate away from areas artificially cleared of macroalgae (Edgar et al., 2004), which may indicate that other aspects of the reef environment are also significant as habitat, such as topographical relief for sheltering / hiding. It is noted that flat featureless sandy bottom surrounding reef is an effective deterrent to emigration of wrasses away from the reef (e.g. Barrett, 1995a).
During a survey in 2002 of the reef fish fauna of the St Francis Isles in the Nuyts Archipelago, Senator Wrasse were recorded on both relatively sheltered and wave exposed reefs (Shepherd and Brook, 2003b).
In a study of Labrid species composition on boulder reefs of varying wave exposure in N.S.W., Fulton and Bellwood (2004) reported that Senator Wrasse was found mainly on the sheltered, shallow (to 6m), lee side of the boulder reef.
The species is also considered to be a common inhabitant of Giant Kelp (Macrocystis) “forests” in Tasmania (uncited reference, in Edyvane, 2003).
Senator Wrasse occurs on reefs with algal cover of various densities. For example, the species has been recorded in relatively high abundance on flat, basalt reefs with geniculate coralline cover and sparse cover of brown canopy macroalgae, across the north coast of Tasmania (Barrett and Wilcox, 2001). It has also been recorded of reefs with dense cover of macroalgae (Harvey et al., 2004).
Senator Wrasse has also been recorded in seagrass beds and other non-reef habitats (e.g. Kuiter, 1983; Fairhead et al., 2002b; Harvey et al., 2004; Hindell and Jenkins, 2004). During a recent survey of nearshore fish habitats in south-western Australia, Senator Wrasse was recorded in seagrass beds of medium and high density (Harvey et al., 2004).
Senator Wrasse has also been recorded on artificial reefs, such as tyre reefs, and shipwrecks (Branden et al., 1994; MLSSA, 1999a).

Notes on the Biology

Growth

Senator Wrasse grows to around 33cm (Hutchins and Swainston, 2001); however it is noted that Edmunds et al. (2003) recorded a single individual of 40cm, during monitoring of size class composition of Senator Wrasse on nearshore reefs in Victoria.
One of the maximum sizes recorded is 0.625kg, being a specimen taken in Bicheno, Tasmania, in 1974 (Australian Underwater Federation, 2003).
During a survey in 2002 at the Nuyts Archipelago in western South Australia, the average size of observed specimens was approximately 24.2cm (SE 0.6) (Shepherd and Brook, 2003). In Victoria, during a study of the reef fish faun in Bunurong area in 2002 and 2003 (Edmunds et al., 2003), most specimens were observed within the size range 15cm – 20cm.
The species is described as long-lived (Barrett et al., 2002).

Diet

The species eats benthic invertebrates, such as amphipods, crabs and gastropods (Edmunds, 1990; Parks Victoria, 2006). Senator Wrasse is also a predator of abalone (Shepherd and Turner, 1985).

Reproduction and Behaviour

P. laticlavius is a sedentary, site-associated species (Barrett, 1995a, Edgar et al., 2004), with females having overlapping home ranges and males being territorial (Barrett, 1995a). During a study in Tasmania, the home range was estimated to be about 175m² (Barrett, 1995a, cited by Ward et al., 2001).
Senator Wrasse is a sex-changing species. (i.e. a protogynous hermaphrodite) (Barrett, 1995a).
During the spring breeding season male Senator Wrasse become territorial and swim above the macroalgae-covered reefs, with fins erect. Females release eggs (reportedly millions) above the reefs. Following fertilisation and egg development, juveniles float in the ocean currents for 2 -3 weeks (uncited reference, in Parks Victoria, 2006).

Other Information

Like many other Labrids, the Senator Wrasse changes colour and pattern with growth. The terminal phase males are usually being green with a red to purple stripe on the side of the body (Australian Museum, 2002b). Juveniles and females are paler, pink or reddish, with blue spots sometimes being visible.
The species is reported to have a significantly slower swimming speed compared with Labrids that occur in areas of faster water movement, on exposed reefs (Fulton and Bellwood, 2004).

Fisheries Information

Commercial

Senator Wrasse is a lesser component of the commercial catch of three wrasse species in South Australia (Knight and Johnson, 1999). The commercial wrasse catch is shown in the synopsis for Blue-throated Wrasse, which is the main wrasse species taken commercially in South Australia.
The species is vulnerable to capture in 2-inch and 3-inch gill nets. During experiments reported in Walker et al., (2003), 464 and 122 Senator Wrasses were caught per 1000 km hours, using 2-inch and 3-inch gill nets respectively. Experiments in coastal waters of Tasmania also showed that this species is vulnerable to capture in small-mesh (e.g. 89mm) gill nets (Murphy and Lyle, 1999).
The species is vulnerable to capture in rock lobster fisheries. Bycatch statistics for this species in the South Australian Rock Lobster fishery are not available; however example of catches of unspecified Labrids in that fishery (which may include a portion of P. laticlavius) are provided in the section on Labridae. In a study of bycatch in the Tasmanian Rock Lobster fishery, 18,302 rock lobster pots (without escape gaps) were examined between 1992 and 1997. During that period, 80 Senator Wrasses were caught (i.e. an estimate of 229 pot-lifts required for the capture of 1 animal) (Frusher and Gibson, 1998, cited by Ford, 2001). The study also showed that lobster pots with escape gaps can significantly reduce the number of wrasses caught (Frusher and Gibson, 1998, cited by Ford, 2001).
Senator Wrasse is collected in Tasmania for the aquarium industry. The permitted annual catch limit is 300 individuals, with a fishing block limit (6 x 6 nautical miles) of 50 individuals (DPIWE Tasmania, 2005b; Australian Government DEH, 2005b).

Recreational

The species is taken by anglers, and some clubs and associations keep records of the maximum sizes caught (e.g. Australian Anglers Association – Victorian Division, 2003; New South Wales Fishing Clubs Association, 2003; Australian Anglers Association - W.A. Division, 2005).
During the National Recreational and Indigenous Fishing Survey, recreational catches of Senator Wrasse in S.A. were not recorded at species level; however during the survey period, a total of 64,199 wrasses were taken in S.A. (SARDI data, September, 2005).  The proportion of the wrasse catch that comprised P. laticlavius cannot be determined, but it is likely to be lower than the catch of commonly fished species such as N. tetricus.
The species is taken by spear fishers in some areas. Senator Wrasse was one of the species caught in spearfishing competitions in South Australia during the 1980s (Johnson 1985b). Some spearfishing clubs report catches of wrasse species (including Senator Wrasse) via internet forums. The national record-sized specimen was taken by spearfishing in 1974, in Tasmania (Australian Underwater Federation, 2003).
Experiments with recreational gill nets in Tasmania (Lyle et al., 2000) showed that P. laticlavius are caught with this gear type in reef areas; however catch figures for recreational gill net fishing in Tasmania are not available.

Vulnerable Characteristics of the Species and Threatening Processes

As is the case with other temperate Labrids, Senator Wrasse has a number of characteristics that make the species vulnerable to over-exploitation, and population decline.
Senator Wrasse is caught in a variety of commercial and recreational fisheries across the range, and is also collected for the aquarium trade (in Tasmania). Given the life history characteristics of Labrids, fishing may be a threatening process, but there are no specific data for this species. The protogynous hermaphroditism - i.e. sex change - in this species may also increase population vulnerability, and heavily fished populations may suffer imbalances in population structure.
Senator Wrasse is a very inquisitive species (Edgar, 2000; Parks Victoria, 2006) that will follow divers. This behaviour may make populations in some areas vulnerable to spear fishing.
The species is territorial and strongly site-associated within shallow subtidal habitats, particularly macroalgae-covered reefs. In some parts of its range, such habitats in which this species occurs are subject to damaging processes, such as eutrophication from sewage and wastewater discharges, sedimentation, and physical damage from dredging and near-shore developments, amongst other impacts (e.g. for Gulf St Vincent in S.A., see Shepherd, 1970; Shepherd et al., 1989; Cheshire et al., 1998; Cheshire and Westphalen, 2000; Turner and Cheshire, 2002; Fairhead et al., 2002b; Baker, 2004; Westphalen et al., 2005).

Research Requirements

There are insufficient data on the (i) relative abundance / populations sizes within the range (including South Australia); (ii) the biology (e.g. maximum age, growth, fecundity), life history characteristics and population dynamics of the species; and (iii) the extent (and potential effects) of commercial and recreational fishing on this species.

Management Requirements

Ongoing control of impacts that reduce the quality and cover of nearshore reef habitats, particularly in metropolitan areas.
Commercial catches of wrasses in State waters should be separated by species, and catch statistics should be monitored over space and time.
Plans for marine protected areas in S.A. should give due consideration to the declaration of nearshore sanctuary zones that include such site-associated species as Senator Wrasse.

Other Information

The species is known to occur in many of the marine parks and sanctuaries in Victoria, such as Bunurong (where Senator Wrasse is one of the dominant reef species), Barwon Bluff, Rickett’s Point, Point Addis, Popes Eye (Port Phillip Bay), Port Phillip Heads, Phillip I., Gabo I., Marengo Reefs, Wilsons Promontory and Merri (Edmunds et al., 2000, 2003, 2004; Ferns and Hough, 2002; Plummer et al., 2003; Hart et al., 2005; Dedrick, 2004; Koss et al., 2005).
Senator Wrasse occurs in a number of marine reserves in Tasmania, including Maria Island and Port Davey / Bathurst Harbour (Parks and Wildlife Service, 1998; DPIWE, 2005e), and the proposed Three Sisters / Goat Island (Barrett and Wilcox, 2001).
Senator Wrasse is one of the species recorded by divers in the Reef Watch programs in South Australia and Victoria. It is noted that Edgar et al. (2004) considered that divers’ visual estimates of Senator Wrasse abundance may be under-estimated in areas with dense macroalgae.
Senator Wrasse is of interest to recreational divers for viewing and photography.