Engraulidae: BD III A1
Engraulis encrasicolus Linnaeus 1758, and Stolephorus ?punctifer (Fowler, 1938)
Cape anchovy and Buccaneer anchovy
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 |
1160-1310 x530-605 |
0 |
NA |
segmented |
narrow |
NA |
70% of NL |
40 |
Egg: This egg is easily identified by its unique shape, segmented yolk and lack of an oil globule. No pigment was noted on the developing embryo. Incubation was about 30 hours.
Larva: The 3-day larva has the typically elongated gut of an engraulid (B, white arrow), and an early developing gas bladder (B, black arrow). Black pigment spots extend ventrally from just behind the head, to just short of the notochord tip(C). B & C: 3 days.
No attempt has yet been made to rear this larva. Initially thought to be the egg of the Cape anchovy Engraulis encrasicolus, summer spawning in warm KZN waters seemed to put this in doubt. And early DNA sequences suggested that this was a Stolephorus, based on three matching egg sequences, which do not match those of 4 adult encrasicolus from the western Cape (BOLD reference). They did match a larval engraulid collected in November 2003, at the mouth of the Lovu estuary, about 30km south of Durban (tentatively, but incorrectly identified as Stolephorus holodon), 4 small juveniles collected at the mouth of Durban Harbour in November 2005 and another collected from the same locality in December 2005. More recently, four juveniles of 35-42mm SL were taken from the gut of a Scomberomorus commerson caught off Pomene in Mozambique (22 50S, 35 33E). Clarity awaits the sequencing of mature adults. Delsman (1931) illustrated a similar egg, which he ascribed to S. pseudoheterolobus, listed by Wongratana et. el.(1999), as a synonym of Encrasicholina heteroloba (Ruppell, 1837). A related species E. punctifer, is known from our waters (Whitehead and Wongratana, 1986, under the genus Stolephorus). Of the four species of anchovy known from South African waters, S. punctifer is the only one for which adult barcode is not yet available.
In December 2008, large shoals of anchovy appeared in the Durban to Park Rynie area of the coast. Simultaneously, large numbers of these eggs appeared in my samples. Two adults taken from these shoals keyed out to E. encrasicolus, and barcoding has confirmed this identification. Three larvae hatched from planktonic eggs have also matched these adult encrasicolus. Evidently there are two anchovy species with very similar eggs spawning in KZN waters; it remains to be seen whether the eggs are separable by eye.
Anders (1975) reported E. encrasicolus eggs from as far north as Richards Bay on the KZN coast, in December 1973, and Connell (1985, 1989) found this egg in large numbers off Richards Bay, but the species is uncertain.
This was the 10th most common egg in the Park Rynie samples (Introductory notes, Section 7, Table 3), but was only seen on three occasions in the DHM samples, in each case limited to one or two eggs. It is a summer spawner, from November to April, off Park Rynie (blue graph). By contrast, my collections off Richards Bay between 1981 and 2003, yielded 83% of the eggs (107110 eggs in 69 samples) in the winter months of May to August (Connell 1985, 1989, 1997a, 2003). After almost disappearing from Park Rynie samples in 2002-2004, the egg was collected in fair numbers in 2005 (white graph). Unfortunately, due to an error of replacing a major panel in my net (my fault, I sew my own nets!), with netting which was 500µm, instead of 300µm, the collection of this and other eggs with a diameter near 500µm, was compromised, over the period March 2001 to December 2003, when the error was detected (see also BKIIIA2 and LIIIG7).
In the linked samples from Park Rynie, these eggs were more common offshore (74%), supporting their rarity in DHM samples. Nevertheless, the percentage is lower than the two indicator species, suggesting most spawning on the 20-30m depth contours. See Section 7.3 and Table 1 of the Introductory Notes, for more information on the linked samples.
linked samples |
Offshore |
Inshore |
Eggs |
5734 |
2017 |
Hits |
53 |
37 |
.