Engraulidae: BD III A1
Engraulis encrasicolus Linnaeus 1758, Encrasicholina punctifer Fowler, 1938, and another.
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 was made to rear this larva, but barcoding suggests there are three species of engraulid spawning an oval egg with no oil globule off Park Rynie. To date (October 2014), the picture is as follows:-
The barcodes of 7 adults of Engraulis encrasicolus, collected from Luderitz Bay in Namibia (5), and the KZN coast (2), have matched 14 eggs collected off Park Rynie. One adult of Encrasicholina punctifer, collected at Park Rynie, has matched 13 eggs and 2 larvae from Park Rynie, the 2 larvae as by-catch while collecting eggs with my plankton net, or from fish stomachs. The difference in barcode between these two species is however quite small and needs futher investigation. The third species, as yet unidentified, for lack of an adult barcode, is known from barcodes of 9 eggs and 14 plankton collected larvae from Pomene, Mozambique (3), Durban Harbour mouth (5); Ilovu estuary (1); Clansthal (2) and Park Rynie (3).
From the above it is evident there are at least 3 species of engraulid in the area, with a similar egg. Both S. holodon and S. indicus can be ruled out as their sequences do not match this group in my dendrogram (BOLD), and the former has an oil globule in the egg. 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). 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 type of egg in large numbers off Richards Bay, but the species is unknown, as they were not barcoded.
This was the 9th 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 abundant in 2008 and 2009(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 (76%), 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 |
14655 |
4662 |
Hits |
85 |
76 |
.