Sparidae: L III B1

Polysteganus undulosus (Regan, 1908)

Seventy-four

Egg diameter in µm	Number of oil globules	Diameter of oil globule in µm	Yolk texture	Perivitelline space	Position of oil globule at hatch	Gut length   at eye- pigment stage	Myomeres
960	1	190	clear	narrow	stern	42% of NL*	25

*eyes unpigmented in this case.

Egg: A couple of unfertilised eggs, extruded from a female in spawning condition, were placed in a bucket of seawater, aboard ship, after which a drop of milt from a male was added to the bucket. Both fish were released, but positively identified as P. undulosus. The development of the egg could not be followed, as facilities were not available on board ship.

Larva: The early larva was photographed, two days post fertilization, but failed to survive any longer. B: 2 days post-fertilization.

The seventy-four is one of the species of indigenous sparids, which migrate north, from the Agulhas Bank, into KZN waters in early winter, to congregate in spawning aggregations in 60-75m water depth. Commercial line-fishermen, operating from 20-25m fishing boats of about 75 tonnes, in the 1950’s and 1960’s, learned to meet the fish off the eastern Cape coast, and to follow the shoals up the coast, along the 60-75 metre depth contours (F.C. (Billy) Clarke pers. comm.). Initially, fish were reproductively dormant, east of Bird Island on the east edge of Algoa Bay (February to April; 34° 00” S, 026° 45”E), but as the shoals moved eastward, gonads developed, until they reached the Park Rynie area, when gonads were large, and ripe running (August to October). Clarke reports that they caught reproductively active fish from Park Rynie in the south-west, to Cape Durnford 28° 58”S, 032° 10”E) in the north-east, but also occasionally among the steenbras (Petrus rupestris) off Brazen Head, much further south (32° 00”S, 029° 20”E). They also recognised a nursery area in shallower water in the Kei Mouth-Morgans Bay area of the eastern Cape (32° 43”S, 028° 30”E), in 30-45 metres, where fish of about 2kg were common. While these notes are anecdotal, they are consistent with known distribution of adults and juveniles. Juvenile seventy-four are virtually unknown in KZN waters, indicating that larvae move south to nursery areas inshore along the eastern Cape coast. Tagging of adult fish has not yet demonstrated movement of adult fish south, after spawning in KZN waters, but local fishing in a variety of water depths has failed to demonstrate a significant presence in KZN waters in summer. At the time of writing, researchers are reporting a modest recovery of this species, after its virtual annihilation, as a commercially exploitable species, up to the 1980’s, and its protection from angling, since1998 (Mann, 2007).