SANDELIAS FROM THE CAPE, SOUTH AFRICA
Jim Cambray (Albany Museum, Grahamstown) and David Armitage (AAGB)
The South African Cape is renowned for its endemic fauna and flora. There are equally unique fish here including two of the least-known anabantoids, of the genus Sandelia, which gets its name from a former chief of the Gaika branch of the Xhosa, Sandile.
The main difference between Ctenopoma and Sandelia is that the latter have a very simple labyrinth organ, the simplest of all the anabantoids, in fact. This may because the accessory respiratory function is not so important in their habitats. Perhaps to compensate for the loss of buoyancy, they have prolongations of the air bladder in comparison with Ctenopoma. They have a non-serrated sub-operculum with only 2 opercular spines, while Ctenopoma has many more. The scales of Ctenopoma are ctenoid while those of Sandelia are cycloid.
The Cape Kurper
S. capensis is known as the Cape Kurper. It is found from just south of the Olifants River, (north of Cape Town) in the coastal drainages of the Cape as far as Port Elizabeth. The largest reported specimen is 215mm, but they start breeding at a size of 52mm.
S. capensis feeds along the edges of rivers of both rivers and lakes and, although it mainly eats aquatic insects, it can also be a voracious predator or browse on vegetation and detritus. Unfortunately it can also form the diet of introduced fish.
In the de Hoop Lake, spawning occurred in 2 distinct periods; mid Spring and mid-Summer when the temperature was 20.5°C or above. When spawning, the males become dark and they appear to hold territories. The female is much lighter and the pair circle and apparently embrace about 15 cms from the substrate. After spawning, the males become light and guard the scattered, adhesive eggs where they have fallen, sometimes among roots or otherwise on the bare gravel bottom.
Wit River habitat of S.capensis
This typical upland habitat of the Cape Kurper, lies in the Baaviaanskloof wilderness area, near Port Elizabeth. Here the clear water flows over white quartz gravel with larger boulders between which the kurpers take refuge. The habitat is shared with the endemic red-fin minnow, Barbus afer.
The Eastern Province Rocky
The second species, is S.bainsii, named after the South African geologist and known as the eastern Province Rocky. This fish is darker than S.capensis, has smaller scales and a more-pointed snout. Adults have serrated tails. There is a line or lines from the corner of the eye and adults have a greenish or yellow sheen to the body. They may reach 32.5cm.
It only has a limited distribution, from the Kowie River east to the Buffalo River (very roughly between Grahamstown and E.London) and it is this that gives S.bainsii its vulnerable status along with the threat from introduced sport fish and human degradation of the aquatic environment.
They are only abundant in the middle and upper middle reaches of the rivers in which they occur and are commonest in clear water just below weirs, indicating a preference for rocky areas in clear, silt-free water. The water temperature may vary from the lower 20s °C to below 15°C. Their diet comprises largely insect larvae and fish.
The spawning behaviour of the East Cape Rocky has been recorded for the first time at the Albany Museum as part of the captive breeding programme there, partly funded by aquarist societies. The male prepares a spawning area by clearing the substrate with rapid sweeping body movements. The male invites the female to his spawning area and chases away other males. Sometimes he takes the entire head of the female in his mouth and gives her a shake. She remains fairly inactive, above the male. When the female finally consents to enter the area she is very passive and maintains a position above the male, with her head slightly pointing downwards. When the male is properly aligned he wraps himself in a 'U' around the female. He then anchors himself with the contact organ pushed into her abdomen, squeezed the abdominal area of the female with a quick head movement at which time the eggs and milt are released. During the mating clench the female was not normally turned over, as in some anabantoids, but remained upright.
After several mating sessions the female she comes back to the spawning area and aligns and waits for the male to do another mating clasp. The number of eggs released during any one embrace can vary from several to a few hundred. . The male then guards the spawning area. Eggs were light yellow, adhesive, demersal and 1.3 mm in diameter with a single 0.6 mm oil globule.
Latest Conservation status of the Nahoon and Buffalo River East Cape Rockies
One of us (Jim Cambray) went on a recent survey of the Nahoon and Buffalo River sites with Wayne Haselau and Dr Anton Bok, two conservators who have an interest in the Rocky. They are both retiring so Jim thought it was time to look at the sites they knew about. Our efforts in the Nahoon were not successful and NO Rockies were seen. In the Buffalo River only small populations of the distinctly yellow (Kowie River rockies are grey to black) Rockies were found near the beautiful Amatola forests. Human population growth is taking its toll and urgent measures are needed to prevent these populations of rockies from facing extinction in the near future. We saw evidence of recent cutting down of beautiful forest trees, also there were abundant goats in the area so there is no chance for regrowth. It will be necessary for someone to work with the local community to save both the forest and this distinctive African anabantid which in the end will conserve the local mountain springs which the local people depend on for survival.
The Algoa Regional Services Council has put aside a small reserve for the eastern Province Rocky, the Blaauwkrantz Nature Reserve, which is on the Blaauwkrantz River, a tributary of the Kowie River system. This was the first nature reserve specifically set aside for a species of the Anabantidae. Since then, the alien water fern, Azolla filiculoides, has been introduced into the Kowie River system. The eastern Cape has prolonged drought periods with little or no flushing flows in the rivers. This condition, combined with the enriched waters, is ideal for the growth of the water fern.
The main refuge pools are completely covered with dense mats of Azolla which excludes light and upsets the food chain. These mats are so dense that birds, crabs and monitor lizards can walk across them. With so few refuge pools available, the only safe means of Azolla eradication at the Blaauwkrantz reserve was manual removal. This is possible, but very time consuming. Volunteers, such as school children, have given many hours of free labour but funds are required for transportation and equipment.
The Blaauwkrantz pool was completely cleared of the water fern in November 1991. After the rains in November, a breeding population of the eastern province rocky still existed in the Blaauuwkrantz reserve. But all is not well. During the hard work of volunteers over weekends, during which up to 5 tonnes of the water fern were removed from the main pool in the reserve, it was found that the young-of-the- year fish were stranding themselves on the Azolla mats when they jump out of the water to catch insects or to avoid predators.
Grey Reservoir lies just outside of Grahamstown, above the pollution below Grahamstown. It has been selected as another area where the Eastern Cape Rocky may have a chance to survive. However, there are problems with this reserve! People think that they can stock the reservoir with bass (an alien species) and catfish (a translocated species) and these illegal stockings will negate our positive moves. On the positive side, we have the backing of the Municipality, Nature Conservation and the area around the reservoir has now become the National Arboretum for Peace and Reconciliation. This year the Minister of Water Affairs and Forestry (Prof. Kader Asmal) opened the Arboretum, and the Minister released some fish into the reserve after planting a tree.
In November 1995 another potential reserve for the Eastern Cape Rocky was located on a farm owned by Wendal Muir. Alan Stephenson, a Nature Conservation official, brought my attention to several small reservoirs ABOVE the pollution in the Bloukrans. On the map, the river on which the reservoirs occur has no name but the area is known as Pigot's Park. The water quality is very good, the reservoirs are well established with the indigenous floating heart (Nymphoides indica) around the perimeter and a member of the Characeae (Nitella knightiae) in the centre. The reservoir also had a good population of the chubbyhead barb (Barbus anoplus), which is part of the normal diet of S. bainsii. The last 20 of the Sandelia bred at the Albany museum were released here. These yearlings should have a good chance of survival and as the minnows had recently spawned, there was abundant food for them. They will just have to work a bit harder for it than they did in the laboratory.