Brachionichthys hirsutus ( Lacepede )

Peter R. Last, Daniel C. Gledhill & Bronwyn H. Holmes, 2007, A new handfish, Brachionichthys australis sp. nov. (Lophiiformes: Brachionichthyidae), with a redescription of the critically endangered spotted handfish, B. hirsutus (Lacepede)., Zootaxa 1666, pp. 53-68 : 61-67

Brachionichthys hirsutus ( Lacepede)

Figs. 4-5, Table 1

Synonymy.

Lophius hirsutus Lacepede, 1804 : 202, 210, pl. 55 (3), original description; type not designated; coast south of Australia, presumably Tasmania.

Chironectes punctatus Cuvier, 1817 : 434, pl. 18, figs. 2, 5, replacement name for Lophius hirsutus Lacepede , preoccupied (see Pietsch, 1985); lectotype MNHN A. 4627, by subsequent designation of Le Danois (1964: 139); paralectotype apparently skeletonised and subsequently lost.

Chironectes hirsutus . Valenciennes, 1837: 434, new combination.

Material. MNHN A. 4627 (lectotype), 78.7 mm SL, coast of southern Australia , 1800-1803 . Non-types: 81 specimens. CSIRO C 2986 , 89.3 mm SL, Coles Bay , Tasmania, GP. 42° 06′S, 148° 09′E, 5 Aug. 1957 ; CSIRO H 797-01 , 63.5 mm SL, Derwent Estuary , Tasmania, 42° 53′S, 147° 21′E, 5 m, 18 Jul. 1987 ; CSIRO H 2629- 01 , 80.3 mm SL, CSIRO H 2629-02 , 82.0 mm SL, CSIRO H 2629-03 , 78.2 mm SL, CSIRO H 2629-04 , 7 specimens, 69.1-80.9 mm SL, Frederick Henry Bay , Tasmania, 42° 53′S, 147° 33′E, 6 Jan. 1982 ; CSIRO H 4114-01 , 3 specimens, 67.3-83.4 mm SL, CSIRO H 4114-02 , 57.2 mm SL, CSIRO H 4114-03 , 66.0 mm SL, CSIRO H 4114-04 , 61.0 mm SL, CSIRO H 4114-05 , 64.8 mm SL, no data ; CSIRO H 4115-01 , 59.2 mm SL, Derwent Estuary , Tasmania, 42° 53′S, 147° 21′E, 1 m, 4 Sep. 1986 ; CSIRO H 6564-01 , 63.9 mm SL, Derwent Estuary , Tasmania, 42° 53′S, 147° 21′E, 7 m, 26 Mar. 2007 ; CSIRO T 2 , 6 specimens, 55.5-72.3 mm SL, Frederick Henry Bay , Tasmania, 42° 53′S, 147° 33′E, 8 m, 28 Jul. 1981 ; CSIRO T 3 , 69.6 mm SL, Derwent Estuary , Tasmania, 42° 53′S, 147° 21′E, 6 m, 15 Apr. 1985 ; CSIRO T 7 , 78.9 mm SL, Storm Bay , Tasmania, 43° 04′S, 147° 29′E, 34 m, 1 Oct. 1980 ; CSIRO T 10 , 4 specimens, 58.8-71.7 mm SL, southeastern Tasmania , Feb. 1982 ; CSIRO T 11 , 70.9 mm SL, Storm Bay , Tasmania, 43° 04′S, 147° 29′E, 60 m, Oct. 1980 ; CSIRO T 1989-01 , 3 specimens, 70.8-73.9 mm SL, Derwent Estuary , Tasmania, 42° 53′S, 147° 21′E, 1 m ; CSIRO T 1990-01 , 2 specimens, 52.0 and 63.7 mm SL, Derwent Estuary , Tasmania, 42° 53′S, 147° 21′E, 1 May 1969 ; NMV A 2305 , 3 specimens, 62.0-72.6 mm SL, Derwent Estuary , Tasmania, 42° 53′S, 147° 21′E, 6 m, 1982 ; NMV A 29404-001 , 59.6 mm SL, D'Entrecasteaux Channel , Tasmania, GP. 43° 03′S, 147° 20′E, 1 Sep. 1964 ; TMH D 80 , 77.9 mm SL, no data ; TMH D 81 , 2 specimens, 66.7 and 69.5 mm SL, Derwent Estuary , Tasmania, GP. 42° 53'S, 147° 21'E, 12 Mar. 1910 ; TMH D 237 , 71.3 mm SL, D'Entrecasteaux Channel , Tasmania, GP. 43° 03'S, 147° 20'E, 2 Jun. 1962 ; TMH D 240 , 5 specimens, 58.8-68.8 mm SL, D'Entrecasteaux Channel , Tasmania, GP. 43° 03'S, 147° 20'E, 1 Jun. 1962 ; TMH D 254 , 10 specimens, 21.0-72.1 mm SL, D'Entrecasteaux Channel , Tasmania, GP. 43° 03'S, 147° 20'E, 2 Oct. 1964 ; TMH D 269 , 2 specimens, 53.7 and 59.4 mm SL, D'Entrecasteaux Channel , Tasmania, GP. 43° 03'S, 147° 20'E, 19 Oct. 1964 ; TMH D 364 , 4 specimens, 46.4-53.0 mm SL, D'Entrecasteaux Channel , Tasmania, GP. 43° 03'S, 147° 20'E, 1 Oct. 1964 ; TMH D 640 , 2 specimens, 67.8 and 70.0 mm SL, Tasmania ; TMH D 650 , 48.8 mm SL, Lymington, Cygnet Estuary , Tasmania, GP. 43° 12'S, 147° 04'E, 14 Jul. 1944 ; TMH D 746 , 63.4 mm SL, Derwent Estuary , Tasmania, 42° 53'S, 147° 21'E, 3 Mar. 1966 ; TMH D 962 , 67.6 mm SL, Derwent Estuary , Tasmania, 42° 53'S, 147° 21'E, 4 Nov. 1969 ; TMH D 965 , 71.5 mm SL, Derwent Estuary , Tasmania, 42° 53'S, 147° 21'E, 23 Nov. 1969 ; TMH D 966 , 70.8 mm SL, Derwent Estuary , Tasmania, 42° 53'S, 147° 21'E, 22 Nov. 1969 ; TMH D 1309 , 70.1 mm SL, Derwent Estuary , Tasmania, 42° 53'S, 147° 21'E, 7 Dec. 1976 ; TMH D 1333 , 71.9 mm SL, Frederick Henry Bay , Tasmania, 42° 53'S, 147° 21'E, 1 Jan. 1979 ; TMH D 1775 , 71.1 mm SL, Derwent Estuary , Tasmania, 42° 53'S, 147° 21'E, 2 Oct. 1981 ; TMH D 1892 , 59.6 mm SL, Frederick Henry Bay , Tasmania, 42° 53'S, 147° 21'E, 9 m, 12 Feb. 1977 ; TMH D 1929 , 66.1 mm SL, Derwent Estuary , Tasmania, 42° 53'S, 147° 21'E, 19 Jan. 1971 ; TMH D 1938 , 45.7 mm SL, D'Entrecasteaux Channel , Tasmania, GP. 43° 03'S, 147° 20'E, 22 Jul. 1984 .

Diagnosis. Esca small, 15-26 (mean 20)% of illicium length (including esca); illicium very slender, without dermal spinules, length 19-20 (mean 20)% SL, 2.3-2.4 times in head length; eye moderate, exceeding 5.4 times in head; body entirely covered with close-set, non-imbricate scales; scale bases subcircular with long unicuspid spinules (except for those closely-associated with pores of the acoustico-lateralis system); spinules originating from middle of scale base, variable in length over body; second dorsal-fin rays 17-19 (mean 18), fin base 61-64 (mean 62%) SL; length of first ray of first dorsal fin 0.7-1.0 times length of longest ray of second dorsal fin; anal-fin rays 8-10; usually with 7 pectoral-fin rays; upper body usually covered with fine dark spots or short streaks (rarely with long streaks on head); caudal fin with dense coverage of fine spots, forming a dark submarginal bar in juveniles.

Description. D1 2, n = 80 non types; D2 17-19, usually 18, n = 69; A 8-10, very rarely 8, n = 69; Pc 6-8, usually 7; Pv i, 4; C 1 + 5-7 (usually 6) + 1-3 (usually 2) = 9; Vt 9-11 + 13-15 = 22-26 (usually 23-24), n = 14; Br 5, n =l.

Body moderately elongate, weakly compressed; upper anterior profile convex, elevated slightly, upper eye close to dorsal margin; subtriangular when viewed anteriorly; nape usually humped in large individuals; anterior ventral profile weakly convex to flattened; abdomen globose; caudal peduncle elongate, length 7- 11% SL. Head relatively short, 45-48% SL; snout short, 4.8-5.8 times in head; eye small, 5.4-6.7 times in head length; gill opening small, aperture smaller than pupil, located slightly above and behind insertion of pectoral fin; nostrils large, openings mostly protruding slightly; posterior opening elevated above anterior opening, adjacent orbit. Mouth relatively small, terminal, moderately protractile; upper jaw slightly oblique, 3.6-4.1 in head; upper lip very fleshy; lower lip fleshy medially, connected laterally to lower jaw by fleshy dorsoventrally flattened fold; angle of jaw partly retracting into groove; tongue well developed, rounded apically. Teeth minute, villiform, in broad bands in both jaws; band in lower jaw longer and broader distally than in upper jaw; vomer edentate.

Skin rather thick, covered with pungent, unicuspid scales; no separate wart-like patches of skin; small dermal flap present on mid-arm of pectoral-fin; flap thallate, strongly compressed, subcircular with an irregular margin, sub-equal in size to gill opening; no other dermal flaps on body. Body scales close-set, not arranged in defined rows; distributed over entire body, those on belly slightly smaller than those on upper surface; spiny scales present on orbital membrane; spinules slender, exposed apically; basal half of spinule and scale base usually embedded beneath raised mound of thickened skin; scale bases subcircular with weakly irregular margins, their width slightly exceeding or subequal to spinule length; spinules arising from near middle of scale base. Anterior margins of leading rays of first and second dorsal fins, and usually lateral margins of subsequent rays of these fins, lightly covered with minute spinulose scales; upper surface of some pectoral-fin rays and basal rays of caudal fin often weakly spinulose; remaining fin rays and all fin membranes naked. Illicium naked, covered with thin skin. Scales of acoustico-lateralis system bispinulate, with small central pore on oval base flanked by slender apical spinules; scales widely separated and arranged in ill-defined rows; pronounced at chin apex, otherwise indistinct on head.

Illicium terminal on snout, very slender, 2.3-2.4 times in head, 1-1.6 times in length of first ray of first dorsal fin; apex of esca reaching to or just behind base of second ray of first dorsal fin when fin depressed; partly retractable into shallow fleshy groove on either side of first dorsal fin; esca small, not bulbous, 3.8-6.8 times in length of illicium; filamentous branches multiple irregular, dense, short thallate; illicial base weakly bulbous. First dorsal fin moderately well elevated; rays unsegmented; first ray recurved slightly, originating less than half an eye diameter behind base of illicium, distinctly longer than second ray; membrane of fin terminating above to just behind level of insertion of pelvic fin; first dorsal-fin base 2.4-2.8 times in second dorsal-fin base. Second dorsal-fin rays tall, penultimate posterior rays longest; most rays simple, posterior rays occasionally branched; fin base moderately elongate, 61-64 % SL; longest second dorsal-fin ray 0.7-1.0 times in longest first dorsal-fin ray; fin membrane relatively thin, not concealing bases of fin rays. Anal fin moderately elongate, penultimate posterior rays longest; anal-fin base 1.9-2.2 times in second dorsal-fin base. Pectoral fin strongly arm-like, radials elongate, relatively slender, extending posteriorly for about an eye diameter behind gill opening; fin rays digitiform, slender, membranes deeply incised, increasingly so posteriorly, tips flexible, slightly flattened (often recurved distally). Pelvic fin elongate; rays digitiform slender, rather deeply incised; anterior spine short, embedded and indistinct; fin located on ventral surface, usually directed ventrolaterally, base aligned horizontally; interpelvic space broad, flat to slightly concave. Caudal fin moderately elongate, narrowly rounded to subtruncate; length 3.5-4.6 times caudal peduncle.

Coloration. In life (based on underwater photographs) - Upper body pale whitish or pinkish; variably and densely covered with small, closely set, orange, brown or blackish spots and/or short streak-like markings; streaks usually formed from coalesced spots; spots and streaks often with yellow or orange borders; large brownish blotches often present below origin and insertion of second dorsal fin; ventral surface of head and belly uniformly whitish, pinkish or orange, spots rarely present; markings usually absent from lips and ventral surface of tail; markings on sides more often streak-like than those of dorsal surface; often with lines of streaks radiating posteroventrally below eye; streaks and spots on sides of tail often arranged in well-defined longitudinal rows; gill opening white, obvious. Illicium uniformly pale or dusky. Fins fully or partially spotted; spots usually smaller than those on body; margins often white. First dorsal fin and most of second dorsal fin with dense covering of fine spots; distal anterior and posterior parts of second dorsal fin with additional patches of slightly larger black spots, these patches appear as blotches when fin depressed. Caudal fin densely spotted; basal spots pale, often yellowish; those on outer third of fin distinctly darker and larger. Anal fin usually pale anteriorly, dark spots confined to posterior third of fin. Pectoral and pelvic fins with densely spotted dorsal surfaces; ventral surfaces usually uniformly whitish. Ventral-most markings on body, spots on proximal areas of fins, and membranes of anal, pectoral and pelvic fins often bright yellow.

In preservative - Body pale, markings usually persistent; spots varying from orange-brown to black. Oldest material faded to white but darkest markings on second dorsal and caudal fins persistent, and some spotting usually evident.

Size. Attaining at least 90 mm SL (about 130 mm TL), adults commonly ~60-75 mm SL. Egg masses contain about 80-250 eggs, each about 1.8-2 mm diameter; egg capsules about 3-4 mm diameter. Newly hatched juveniles about 6-7 mm SL.

Distribution. Demersal inshore, with an extremely narrow geographic and depth distribution. It is restricted to the Derwent Estuary and the adjacent bays of southeastern Tasmania. Populations appear to have been reduced significantly since its discovery and it is now considered to be critically endangered (IUCN, 2006). Hence, locality data in the materials section has been generalised to protect extant populations from selective poaching. A few specimens have locality records from well beyond the current known geographic range. The northern-most record is from near Coles Bay, central eastern Tasmania (near 42° 06′S, 148° 09′E) , and the most southerly recorded is listed as Lymington, in the Cygnet Estuary (near 42° 09′S, 147° 04′E), an arm of the D'Entrecasteaux Channel . Occurs at depths of 1-60 m but anecdotal evidence suggests a range commonly of ca. 5-15 m.

Etymology. Commonly referred to in the vernacular as the Spotted Handfish.

Comparisons. Brachionichthys hirsutus can be distinguished from B. australis based on its colour pattern which is more densely spotted, particularly on the caudal fin, and which usually lacks the thin longitudinal yellowish streaks. It also has typically shorter fins (illicium length 19-20% vs. 23-28% SL; 42-44% vs. 49- 57% of head length; length of first ray of first dorsal fin 0.7-1.0 vs. 1.1-1.4 times length of longest ray of second dorsal fin), a smaller eye (diameter mainly exceeding 5.4, rather than less than 5.4, in head), more second dorsal-fin rays (17-19 mainly 18 vs. 15-18, mainly 17) with a longer fin base (61-64% vs. 55-61% SL).

Remarks. The Spotted Handfish, Brachionichthys hirsutus , was reasonably common in the Derwent Estuary in the latter half of the 20th Century (Last et al., 1983). In 1976-77, during a year-long, fortnightly survey of the fish community of this estuary, B. hirsutus was collected in 15% of day and 12% of night samples using a beach seine (Last, 1983). During the 1980’s, it was ‘commonly encountered by divers’ (Edgar et al., 1982). More recently, populations of B. hirsutus have become severely depleted (Barrett et al., 1996) and the species is considered to be critically endangered by multiple agencies, including the World Conservation Union (IUCN) Red List of Threatened Species (listed as Critically Endangered), the Australian Government (listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999) and The State Government of Tasmania (listed as Endangered under the Threatened Species Protection Act 1995).

Brachionichthys hirsutus does appear to have undergone a recent range reduction. In the 1960’s to late 1980’s, collection data suggest that it was well established in the interconnected bays of southeastern Tasmania, including the D’Entrecasteaux Channel, and a remote record exists for Great Oyster Bay, eastern Tasmania. Although dredging is no longer permitted in this region, no underwater sightings have been made in the Channel despite greatly increased effort from recreational divers harvesting scallops. A single specimen (CSIRO C 2986), supposedly collected in 1957 near Coles Bay is clearly referable to B. hirsutus rather than B. australis . This specimen (89.3 mm SL) is only slightly longer than the four next largest Spotted Handfish (80.3-83.4 mm SL) but is considerably more robust than these specimens (body weight 36 g vs. 18.7-22.7 g). No more material has been taken from this locality and this specimen may represent evidence of a lost relict population. However, some specimens observed during a field survey (Green & Bruce, 2000) were larger with the largest of these being about 130 mm TL (estimated to be about 94 mm SL).

The colour pattern of B. hirsutus varies slightly and these may be related to population differences. Specimens collected together are usually similar in the relative distributions of dark spots and streaks. Reproductive studies indicate that it lays egg masses (Fig. 6) containing about 80-250 large eggs (each about 3-4 mm in diameter) that are held within capsules connected to each other by filaments (Last & Bruce, 1997; Bruce et al., 1998). They live on fine sandy substrates and their egg masses are attached to bottom features, such as shells, marine plants or ascidians (Bruce et al., 1998). Fully formed, juvenile handfishes (about 6-7 mm SL), which lack a pelagic larval period, emerge from the eggs (Fig. 7). They ‘walk’ rather than swim so their dispersal capabilities are poor compared to almost all other fishes (Fig. 8). Consequently, strong population differentiation could be expected. Dark bars on the body, and dorsal and caudal fins of juveniles are persistent to various extents in adults. However, a large juvenile specimen (about 35 mm SL), photographed underwater in the Derwent Estuary (Fig. 9), had a strong juvenile colour pattern without the spotted pattern of adults.