Anchovy (Engraulis japonicus) spawning stock aggregated off the southern coast of Shandong Peninsula in the Yellow Sea since mid-May, and formed a spawning ground center in Haizhou Bay where the water temperature in the 5 m layer was 17°C~20°C. Spawning anchovies were composed of 1~4 year old bodies with a dominant length of 9~12 cm. The main spawning period started from early June, and ended in early July. The ovary oocytes were not synchronized in development, and size distribution displayed distinct peak and valley features. In Stage II, the ovary was composed of Phases 1~3 oocytes, with Phase 2 oocytes accounting for 66.3%; and in Stages III~VI, ovaries were composed of 1~4 oocytes, with the main difference between them being the proportion of Phase 4 oocytes, which were highest in the Stage IV ovary (34.8%), followed by Stage III (28.6%), and Stage VI (17.8%). The Stage V ovary was composed of Phases 1~5 oocytes, with Phase 5 oocytes accounting for the highest proportion (29.8%). During the ovary development from Stage III to Stage V, the change of Phases 3~4 oocytes to Phases 4~5 oocytes was obvious, while the proportion of Phases 1~2 oocytes showed little change. The batch fecundity was estimated at 3507.4±336.7 eggs by using the hydrated oocyte method, and the relative batch fecundity was195.2±12.1eggs/g.Whileusingoocyte-size frequency distribution method, the batch fecundity was 4188.1±443.2 eggs and 7600.3±470.0 eggs, respectively, in Stage V and Stage IV ovaries, and the relative batch fecundity was 233.1±17.5 eggs/g and 415.2±20.8 eggs/g. In assessment of individual absolute fecundity for batch-spawning anchovy in the Yellow Sea, future research is required to clarify the number of spawning batch and variation of fecundity among batches.

Engraulis japonicus, spawning aggregation, ovary, oocyte, batch fecundity, Shandong Peninsula.