Development of eggs and larvae of Stolephorus commersonnii and taxonomic key to fish eggs of the Clupeidae and Engraulidae off China

ABSTRACT

Fish eggs of successive stages of embryonic development, which were identified as belonging to specimens of Commerson's anchovy Stolephorus commersonnii through comparative molecular techniques, were collected from Leqing Bay, Zhejiang, China. Some eggs were reared artificially to obtain samples of successive developmental stages of larvae. The fertilized eggs of S. commersonnii are ellipsoidal and non-adhesive. The surface of the egg membrane is smooth and the perivitelline space is narrow. There is a single oil globule in the irregularly segmented yolk. Newly hatched larvae are transparent and devoid of pigments. Development of the larvae occurs in the following sequence: 8 h after hatching, the anus unfolds; 12 h after hatching, the pectoral fins emerge; 24 h after hatching, the liver and branchial arches emerge, and the alimentary canal differentiates into the oesophagus and intestinal canal; 30 h after hatching, the eyes become pigmented; 36 h after hatching, the upper and lower jaws become distinct; 42 h after hatching, the stellate melanophores emerge; 72 h after hatching, the postlarval developmental stage begins with the emergence of the dorsal fin. Based on the morphology of eggs and larvae of S. commersonnii, a taxonomic key to fish eggs of the Clupeidae and Engraulidae off China is established to provide an efficient and convenient way to identify the egg specimens. The fish eggs of the Clupeidae and Engraulidae off China could be identified to some extent by the buoyancy, shape and diameter of eggs, the number of layers in the egg membrane, the size of the perivitelline space, the number and diameters of oil globules, and the distribution of pigments. Meanwhile, their prelarvae could be identified by the number and diameters of oil globules, the distribution of pigments, the location of the anus and the number of myomeres.

RESPONSIBLE EDITOR:

• Michael Maia Mincarone

KEYWORDS:

• Stolephorus commersonnii
• molecular identification
• development of eggs and larvae
• taxonomic key
• Clupeidae
• Engraulidae

Acknowledgements

We greatly appreciated the support of the captain, the chief engineer and the crew aboard the research vessel Kexue-III and colleagues in collecting samples. We also appreciated the help of Mr Weidong Zhai in measuring salinities of the seawater during this research. This research was conducted at the Ocean University of China and the Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under grant number 31272667; and the Public Science and Technology Research Funds Projects of Ocean under grant number 201405010.