Spearnose skate Rostroraja alba
Photo Alessandro De Grandis
Spearnose skates are very large skates. They can reach 180 cm disk width, and a length of up to 230 cm. They are not often seen by divers around Cape Town - I've only seen a huge one in fairly shallow water off Long Beach, and a smaller one just beyond the rocks at A-Frame. The individual shown was photographed off Fan Reef, which is offshore from Castle Rocks. The size was estimated to be in excess of 150 cm disk width, and was seen in water around 20 m deep.
This skate is described as being a formidable predator, feeding on schooling and bottom-dwelling fish. They are fast and powerful, and glide apparently effortlessly through the water. Alessandro describes the encounter as follows: "It (swam, glided, flew?) past us, banked towards us and did a U-turn, and then cruised right past us again. It was great, I was really stoked! I was about 1.5m from wing-tip to tip, maybe a little longer. Not sure how long.
It didn't look like it was swimming fast, and its wings barely moved, but I just couldn't keep up with it. "
Skates can be distinguised from stingrays by the absence of a sting on the tail, although many are often covered by sharp thorns. The spearknose skate is much larger than any other species which may occur in Cape Town waters, and apart from its size has a very pointed nose, giving it the common name.
Coastal fishes of the Cape Peninsula and False Bay, a divers' identification guide, G Zsilavecz, 2005.