CORE Metadata, citation and similar papers at core.ac.uk Provided by University of Tasmania Open Access Repository Papers and Proceedings of the Royal Society of Tasmania, Volume 125, 1991 55 OBSERVATIONS ON THE TASMANIAN MUDFISH, GALAX/AS CLEAVER/ (PISCES: GALAXIIDAE) by A.P. Andrews (with two tables, one text-figure and two plates) ANDREWS, A.P., 1991 (20:xii): Observation on the Tasmanian mudfish, Galaxias cleaveri (Pisces: Galaxiidae). Pap. Proc. R. Soc. Tasm. 125: 55-59. ISSN 0080-4703. Tasmanian Museum and Art Gallery, 40 Macquarie Street, Hobart, Tasmania, Australia 7000. Meristic and morphometric comparisons are made of the three known populations of the Tasmanian mudfish; mainland Tasmania, Flinders Island and Victoria. The results of observations on the ecology and behaviour are reported. Key Words: Tasmanian mudfish, taxonomy, ecology, behaviour. INTRODUCTION a proprietary flake food. This diet was supplemented occasionally with small pieces of finely chopped worms and Most members of the genus Calaxias are small to medium­ crayfish. sized, fast-swimming, mid-water fishes that can be either lacustrine or diadromous (Whitley 1935). However, one species, Calaxias cleaveri Scott 1934, differs so markedly TAXONOMY from typical Tasmanian members of the genus that at one stage it was referred to tpe genus Saxilaga by Scott (1936). The taxonomy of C. cleaveri has been considered (Andrews Meristic and morphometric comparison of the mainland 1976) at both generic and specific levels, and subsequent Tasmanian, Flinders Island and Victorian populations authors, such as McDowall & Frankenberg (1981) and indicate that the three are conspecific. Jackson & Davies (1982), have neither made nor suggested The principal non-taxonomic differences between C. any alterations. In 1976, C. cleaveriwas known only from the cleaveri and other Calaxias are ecological and behavioural Tasmanian mainland. The species has been subsequently and the results of studies on these aspects of the species are recorded from two Victorian localil'ies (Wilsons Promontory reported here. - Jackson & Davies 1982; Wye River, Otways - Koehn & O'Connor 1990), and from Flinders Island (Green 1984). _Meristic and morphometric comparisons of the three C. MATERIALS AND METHODS cleaveri populations were based on a series of 39 specimens from various Tasmanian localities and a series of six speci­ The methods used to collect galaxiid fishes, as described in mens in the collection of the Queen Victoria Museum and Andrews (1976), by the use of baited wire cage traps were Art Gallery, Launceston (QVML No 1984/5/6), collected unsuitable for C. cleaveribecause of its benthic and secretive from Patriarchs Reserve, Flinders Island, grid reference nature. However, since the species almost always occurs in FR020750. The ten specimens from Wilsons Promontory, small, discrete watetways, dip-netting was successful in most now in the Museum of Victoria, Melbourne (MOV No areas. Specimens for meristic and morphometric study were A2037), were also examined. narcotised in the field with quinaldine and fixed in 10% Measurements and counts made follow Andrews (1976), formalin. Mter fixing, the specimens were transferred to 70% except that all segmented rays, branched and unbranched, ethanol. were counted in the dorsal and anal fins. Ecological observations on C. cleaveri were made at Port The meristic and morphometric data for the three Davey (southwestern Tasmania) at sites about 4 km south C. cleaveri populations are given in tables 1 and 2. Jackson of Bathurst Harbour, in the Dover area (southeastern & Davies (1982) concluded that the Victorian and Tasmania), at sites near the mouth of the Esperance River, Tasmanian populations were conspecific, using data from and in the Bridgewater area of the Derwent estuary, Hobart. Andrews (1976) for the Tasmanian C. cleaveri. The results Observations on the behaviour of C. cleaveri and other of the present study confirm their findings and indicate that species of Calaxiaswere made in the field and on specimens the Flinders Island popula;:wn is also conspecific with these maintained live in aquaria for periods of up to six months. populations. The aquaria were of all glass construction measuring The meristic data indicate a slight tendency towards fewer 0.3 X 0.6 m and 0.4 m deep. In setting up the aquaria, every anal and ventral rays in the Flinders Island specimens but effort was made to duplicate as closely as possible the condi­ the differences are small and the ranges of the Flinders tions under which the specimens were collected in the field. Island and Victorian specimens are within the range of the For C. cleaveri, the bottom of each tank was covered to a Tasmanian specimens. The morphometric data indicates a depth of 80-1 00 mm with sand, mud and coarse decaying longer and narrower caudal peduncle in the Victorian vegetable material collected at the field sites and the tank population and a tendency towards longer paired fins, shorter was filled with water to a depth of 0.3-0.35 m. jaws and narrower heads. Again, however, these differences No form of aeration was provided other than maintaining are small and the possible reasons for such variations are the aquaria in shaded, well-ventilated positions with the discussed elsewhere. tops open to the air. Food consisted of live plankton and 56 A.P. Andrews TABLE. 1 Dars.Ii , 9 1 i 12 U SD 12 lli 1 5 SD 12 3 -j is SO SD L3 16 :\ 1. 13 12 1 1 ~~6 0.28 Flinders 1,~ 5 0.L2 \/ictoria (, 2 0.45 is 2. 0.17 17 TABLE 2 Par;:unett:rs ,'vlean D Max t) , Q 1--1ead/LS 1,->, 19.2 2L2 22,0 TIC, 5-DO/LS 72'<l: 78.7 13.5 ,I <-' 3.20 ii9.0 74.8 S--VO.LS 50,6 53.3 57.S 50.2 52.5 1.9 54.6 L51 PL/PilVO 31.5 42.0 .31.0 35.4 57.6 2.20 39.1 43.4 \/lJVB·",~A() 34.D 38.] 45.4 2.08 OCP/Lep (,2.5 8 to '583 9] 06 lAO 42.0 56.7 1 ., LCP/LS 10.8 1 , .9 l:l. 4 1 ,.L 12.3 0.80 In 183 El)/HL RO l,tO 1,75 120] 12,/1 0.80 IO,') 13.2 15.0 22.6 .J 25<0 28.4 IWIHL 33.9 HW/HL 5.2l the us u,:~d 5i tes up min di:uIlc:ter and 05 In knovvn JisnibutioH. of (;0 ciealJeri IS illustrated Andrews (J (:J the observations on C;', in the field were l:)( [)avies (1 made at Port sOluhwt'stern Tasrnama .. The vvith results or consisted of a nat ailuviaJ Hood about 4 km south of reference DM:'120920 and truttaceus) as recorded G. de.4veri is restricted, of aUuvial tin occur than seHne of the lacustrine area and these have been mined from the mid 1940s until whicl1 are oH~en cO.D.fined to (1 UleV'''>1ll' are in t1"lC fCH'rn of lens·-shapcd 0.5-3.0 m below the surJ~lCe. leaseholder 1.0 m square 'rhese test holes 'Nere t'l'lO collection sltes were recorded at any stained a da rk brovvn These two sites, in the formed an ideal habitat for G. clerw{,li. I)envent and T'ar;];;u estu_aries, consisted. of srnall stagnant were collected frotn the holes aDabranches ofstrearns infO the rivers at (WO, sornerirocs three or four within. the tidal /ifnit). standard 70---80 rnm, bur Pu notirne the about 25--.30 mm were also ~o km FTG. ] -- Distribution Udld."~hi' deaveri The small surface streams which crossed the III cleaveri. None vvere sp<cClme:ns of G, mtlCulatus Pond IIIJ'/Wlnmv Galaxias Port were occasionally found. Two of the test holes were NY",,.,,,,, water and of FreshwaTer Creek on the southeastern side of the mean of mud. of the of G. cleavcri were discussed sediment revealed numerous insect remains, but these were but it was not known if the life roo fragmented for to be determined, included a marine stage. were collected For was carried out at Trial Harbour, on the west coast, from a small at m the outfall of a stream across the beach about 1 .. 0 m the tide leveL The contained black peaty G. truttl1ceus were recorded but no G. sediment water that was saline to the taste. It trapping over several was concluded from this that G cieaveri were salt In the Dover and. areJs) C;. Clell1JCri \vas found tolerant. in stagnant pools in stream beds and roadside lVlcDowail (1 U,.~'LW",'" ditches. In these the water was 025 m or rp,·,,, .. tp{j that the entire life and the substrate consisted of black mud and vegetable material. At one of the Dover localities the water was often covered with a metallic film, a phenomenon also recorded by and Davies It seems that other Tasrnanian populations who attributed it to the presence of metallic sulphides are confined entirely to fresh water. At Port Davey, formed under anaerobic conditions. of the containing G. cleaveri were The habitat of C. cleaveri 011 Flinders Island and southern dense ~nd with no aquatic Victoria is essentially the same as that in Tasmania. The connections to other of water. The pond shown in Flinders Island specimens were taken from a drain leading 2 is one such with the nearest running water to landlocked iagoons and a marsh in Patriarchs Reserve, some 8.0 m distant. In such cases, both and adult some 2 km from the sea. On Wilsons Promontory, where G. cleaveri were collected from the same pond. the Victorian specimens were collected, the habitat was A specimen in the Tasmanian Museum, No D1235, was described by Jackson and Davies (1982) as a small, swampy one of several collected from small cavities in a 0.3 m layer 58 A.P.