S. Afr. J. mar. Sci. 21: 41–50 1999 41 EGGS AND LARVAE OF THE SANTER CHEIMERIUS NUFAR (PERCIFORMES: SPARIDAE) FROM KWAZULU-NATAL, SOUTH AFRICA A. D. CONNELL*, P. C. HEEMSTRA† and P. A. GARRATT‡ The santer Cheimerius nufar is a common reef fish on the east coast of South Africa and a popular target for offshore anglers. The eggs and larvae are described from specimens reared in the laboratory, from aquarium- spawned eggs and eggs collected at sea. Comparisons with eggs and larvae of other local sparids are made and data are presented on the seasonal occurrence of santer eggs in plankton samples. The santer Cheimerius nufar (Ehrenberg, 1830) is a beach front in Durban. The surface of this tank is sparid of moderate size that lives in the western exposed to indirect sunlight during the day and to Indian Ocean, including the Red Sea, Persian Gulf, weak artificial illumination at night. The temperature coast of Oman, east coast of Africa, Madagascar and in the tank remained within 1°C of surf temperatures the Mascarene Islands (Bauchot and Smith 1984, throughout the year. Spawning of santer in the tank Smith and Smith 1986, Randall 1995). It occurs to a was spontaneously within half an hour of sunrise and depth of about 200 m along the coast of KwaZulu- ranged from 05:00 to 06:50 local time during the months Natal (PAG, pers. obs.), where it is more commonly July through October (Garratt 1991). The first egg known as the “soldier” and it comprises about 7% of collections were made in September 1987, using a reef-fish catches made by anglers (Marine and plankton net of 300-µm mesh, towed through the sur- coastal Management, unpublished data). It can attain face waters of the tank at 08:00–08:30. Eggs were a total length of 75 cm and a mass of 6 kg, but most reared in 50-l glass aquaria containing seawater at santer in catches are between 1 and 3 kg. The breeding 20–23°C, with light aeration and a single fluorescent season off KwaZulu-Natal is from June to November, light above each aquarium. The initial food with peak spawning between August and October supplied was the rotifer Brachionus plicatilis; the (Garratt 1985); off the Western and Eastern Cape, water in the aquarium was maintained a light green santer spawn during summer (Gilchrist 1916, Coetzee colour from an outdoor culture of Chlorella sp. Later, 1983). As spawning has also been recorded from the rotifers were supplemented with newly hatched nauplii Gulf of Aden (Druzhinin 1975), it has been suggested of Artemia sp. and copepods from plankton hauls at that santer breed along the entire east coast of Africa sea. At Sea World, 75- and 110-l aquaria were used (Garratt 1985). for rearing, as described by Garratt et al. (1989). Development of eggs and larvae has been described At sea, fish eggs were usually collected passively for several inshore sparid species from the KwaZulu- from an anchored boat off Park Rynie (30°20´S, Natal coast (Brownell 1979, Beckley 1989), but there 30°44´E) on the KwaZulu-Natal south coast. A are no descriptions of the larvae of offshore species. D-shaped plankton net, with a 40 cm bar and 300-µm This paper describes and illustrates the development mesh, was used. The net was designed to float with of C. nufar eggs and larvae derived from fertilized the bar skimming the surface, and the centre of the aquarium-spawned eggs and from plankton net hauls arch weighted to keep the mouth vertical in the water off the south coast of KwaZulu-Natal. Data are also as the net was towed. Towing duration was 10 minutes. presented on the seasonality of C. nufar eggs off the The volume of water filtered (measured for 48 of the south coast of KwaZulu-Natal. approximately 500 samples processed) ranged be- tween 23 and 108 m3 (mean = 53 m3). All samples were taken 4–5 km offshore, in depths ranging from MATERIAL AND METHODS 30 to 60 m. Sampling was conducted between 10:00 and midday. Eggs were transported to the laboratory in sealed The major source of santer eggs for this study was 25-l buckets containing seawater. After concentration the main display tank at Sea World, located on the into glass dishes, eggs were sorted into “species” (or * CSIR, Box 17001, Congella 4013, South Africa. E-mail: [email protected] † JLB Smith Institute of Ichthyology, Private Bag 1015, Grahamstown 6140, South Africa. E-mail: [email protected] ‡ Two Oceans Aquarium, P.O. Box 50603, Cape Town 8002, South Africa. E-mail: [email protected] Manuscript received: November 1997 42 South African Journal of Marine Science 21 1999 Fig. 2: Cheimerius nufar larva at 36 h (BL=2.1 mm fresh, 2.0 mm preserved); RUSI 56118. Stellate melano- Fig. 1: A 24 h egg of Cheimerius nufar (0.80 mm in diameter) phores are dorsally located along the body – – (a) melanophore pattern, (b) xanthophore pattern; (a) melanophore pattern, (b) xanthophore pattern RUSI 56119 lucida drawing device. Xanthophore diagrams were groups of similar species) under the microscope and made from photographs of anaesthetized fish. Live placed in 500-ml glass bowls containing clean sea- specimens were anaesthetized with MS-222 and photo- water for hatching. Large batches of eggs, suitable for graphed in shallow watch-glass dishes using a 35 mm further rearing attempts, were placed in 50-l tanks as SLR camera mounted on the microscope. Larvae described above. Positive identification of C. nufar were photographed on both black and white back- eggs was achieved by rearing the larvae to recognizable grounds, the former to highlight the xanthophores juveniles and by comparing eggs with those collected and the latter for the melanophores. There was some from the spawning of C. nufar in the tank at Sea difficulty in differentiating between xanthophores World. and melanophores on a single monochrome (black Drawings were made from preserved specimens ink) drawing, so, where the two pigments were present, with the aid of a stereomicroscope fitted with a camera they are shown on separate drawings. Table I: Morphometric data of Cheimerius nufar larvae and juveniles expressed as a percentage of body length % of body length Body length (mm) n Body depth Head length Snout length Eye diameter Preanal length 2.0–2.9 5 27 19 3.8 7.6 35 3.0–3.9 3 28 22 6.2 9.3 41 4.0–4.9 3 25 25 7.5 9.1 48 5.0–5.9* 1 25 25 9.6 9.6 48 7.0–7.9 1 33 36 10.5 13.1 59 8.0–8.9 3 39 41 11.7 15.2 65 9.0–9.9 2 37 37 9.5 12.7 63 10.0–10.9 2 39 37 13.2 14.1 61 11.0–11.9 2 35 38 11.6 13.3 63 12.0–12.9 3 37 39 10.5 13.0 63 13.0–13.9 2 41 41 13.5 12.7 65 14.0–14.9 2 37 36 10.8 13.2 63 17** 1 39 38 11.4 12.6 62 19** 1 41 42 15.2 12.1 64 21** 1 36 37 9.7 13.0 62 * = Flexion ** = Juveniles 1999 Connell et al.: Eggs and Larvae of Cheimerius nufar 43 Fig. 3: Cheimerius nufar larva at 48 h (BL=2.8 mm fresh, Fig. 4: Cheimerius nufar larva at 72 h (BL=3.2 mm fresh, 2.5 mm preserved); RUSI 56120. Stellate melano- 2.7 mm preserved); RUSI 56121– (a) melanophore phores were scattered over the body as they migrated pattern, (b) xanthophore pattern ventrally – (a) melanophore pattern, (b) xanthophore pattern meter). Some eggs occasionally had a second (much All the material used in this study was preserved smaller) oil globule. In fresh eggs, the oil globule was in neutralized 5% formalin and then transferred to distinctly pink when the transparent egg is viewed on a 70% ethanol. The samples are kept at the J.L.B. Smith white background. This aided in distinguishing C. nufar Institute of Ichthyology, South Africa, under the cata- eggs from other eggs in the sample. In addition, this was logue numbers RUSI 56118 – 56894. Three juveniles one of the very few species whose eggs were usually (RUSI 54042: 2 specimens and RUSI 28380) were collected fresh (before the embryo was visible), suggest- x-rayed for vertebral counts. ing early morning spawning, as found in the Sea World Terminology and body measurements of larvae tank (Garratt 1991). follow Leis and Trnski (1989), except that their The embryo was clearly visible in the egg at 9 h “inner” and “outer preopercular spines” are designated (21°C), and the oil globule was clear to light amber. here as spines on the preopercle ridge and preopercle Tiny melanophores covered the embryo evenly and edge respectively. Measurements of body length and sparse stellate melanophores were present on the under- various body parts for the larvae were taken with an side of the oil globule (as seen in the buoyant position, ocular micrometer. Body lengths (BL) of specimens with the oil globule dorsally). are of notochord length for preflexion and flexion At 24 h (Fig. 1a), the melanophore pattern of the larvae, and standard length for postlarvae. Lengths of embryo intensified, and three zones of xanthophores fresh specimens were measured on anaesthetized larvae were visible: a pair of greenish-yellow spots, one behind or before they were fixed in formalin; preserved speci- each eye, each comprising 6-8 dots; second, a yellow mens were measured after (at least) 24 h in formalin.