Originally published in Environmental Biology of Fishes, 1996, Volume 45:150. Reproduced here with permission of the author and publisher.

Threatened fishes of the world: Sandelia bainsii Castelnau, 1861 (Anabantidae)

image 117k jpeg - drawing by Penny Meakin

Jim A. Cambray - Albany Museum, Somerset Street, Grahamstown, 6140 South Africa

Common names: Eastern Cape rocky (E), Oos-Kaapse kurper (Afrikaans).

Conservation status: Vulnerable (South African Red Data Book -Fishes, Skelton 1987)

Identification: One of two species in the genus Sandelia which is endemic to South Africa. Both species have a smooth (non-spinous) edge to the lower half of the gill cover and a greatly reduced air-breathing organ relative to other members in the family Anabantidae. D XV-XVI + 9-10, A VII-VII + 9-10, LL 30-32, 22 scales around caudal peduncle. The gill cover has 2 spines separated by a deep membrane-covered notch. The caudal fin is truncate and tessellated. Large mouth with sharp, conical teeth. Large eyes located forward on head. Olive or grey-brown with scattered flecks and spots, single grey bar behind eye, breeding males turn dark and develop visible ctenii on cheek scales (contact organs). Reaches 260 mm SL.

image Drawing of an adult male (31 k jpeg) by Dave Voorvelt.

Distribution: Restricted to the Eastern Cape (32ø34' to 33ø33' S; 26ø06' to 27ø35'E) of South Africa with limited distribution in several tributaries of the Buffalo, Keiskamma, Great Fish and Kowie River systems. Recent collections have confirmed earlier reports of a small population in the Nahoon River.

Abundance: Dwindling numbers in most populations. Recent surveys along the Kowie system revealed only 6 specimens after 4 days of surveying. In a former prime Great Fish River habitat only introduced sharptooth catfish (Clarias gariepinus) were collected. In the Tyume River, a tributary of the Keiskamma River, the S. bainsii population is small and vulnerable to local extinction.

Habitat and ecology: The Eastern Cape Rocky occurs in rocky streams, wedges under rocks or other objects facing upstream waiting for insects, crabs or small fish to come into range. This species is sedentary. Males grow faster, live longer and reach a larger size than females.

Reproduction: Sandelia bainsii mature in their second year, at 80-90 mm SL and at 60-69 mm SL, breed in summer, October to February, which coincides with the rainy season and spawns several times per season. The males guard the eggs as do S. capensis males, and a spawning site is prepared by the male. The eggs are adhesive, 1.3 mm in diameter and have a small oil globule of 0.6 mm in diameter. At 22-23øC the free embryos hatch in less than 2 days and are 3.4 mm TL.

Threats: The species is threatened by poor water quality, invasive alien fish and palnts, loss of habitat due to water abstraction and damming. These are common threats to many freshwater fish species but the limited geographical range of S. bainsii and their small population size exacerbates these threats. They are also very vulnerable to angling pressure.

Conservation action: Immediate action is needed in the remaining habitats of S. bainsii. There is one reserve which has been specifically set aside for this species, the Blaauwkrantz Nature Reserve, managed by the Algoa Regional Services Council. The reserve is situated on the Bloukrans River, Kowie River system. The reserve receives enriched waters from upstream urban and rural areas which has resulted in the quick growth of an introduced water plant, Azolla filiculoides, which completely alters the aquatic habitat. S. bainsii appears to breed well in ponds so that cative propagation may not be a problem. Conservation action should be focused on natural habitat restoration and conservation. Farm dams along the system should be used as breeding and refuge areas.

Conservation recommendations: Further research is required on the spawning requirements of the species and the tolerance of this species to increasing salinity and eutrophication levels.

Remarks: The remaining habitats of S. bainsii require urgent conservation attention. Good sanctuary areas should be located high up in the rivers where the fish naturally occurs so as to avoid many of the negative impacts which occur lower in the river systems, such as poor water quality, excessive water abstraction and alien predatory fish species.

Literature:

Cambray, J.A. l980. Contact organs in fishes of the genus Sandelia (Anabantidae). S. Afr. J. Sci. 76: 277-279.

Cambray, J.A. l98l. The Eastern Cape rocky (Sandelia bainsii). The Naturalist 25(l): 28-30.

Cambray, J.A. 1990. The early ontogeny of the Cape kurper, Sandelia capensis (Pisces: Anabantidae). Ann. Cape Prov. Mus. (Nat. Hist.) 18(8): 159-182.

Cambray, Jim 1993a. Blaauwkrantz Nature Reserve, community involvement and the Eastern Province Rocky (Sandelia bainsii). The Naturalist 37(3): 8-10.

Cambray, Jim 1993b. The Eastern Province Rocky. The Naturalist 37(3): 11.

Mayekiso, M. & T. Hecht. 1988a. Age and growth of Sandelia bainsii Castelnau (Pisces: Anabantidae) in the Tyume River, eastern Cape (South Africa). S. Afr. J. Zool. 23(4): 295-300.

Mayekiso, M. & T. Hecht. 1988b. Conservation status of the anabantid fish Sandelia bainsii in the Tyume River, South Africa. S. Afr. J. Wildl. Res. 18: 101-108.

Mayekiso, M. & T. Hecht. 1990. The feeding and reproductive biology of a South African anabantid fish, Sandelia bainsii. Rev. Hydrobiol. trop. 23(3): 219-230.

Skelton, P.H. 1987. South African Red Data Book - Fishes. S. Afr. Nat. Sci. Prog. Rep. No.137. 199 pp.

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