AGGREGATING INTO SHALLOW BAYS FOR BREEDING DURING WARM SEASON AND OVERWINTERING BY LOCAL OFFSHORE MIGRATION IN Hippocampus mohnikei  

So far all seahorse species habitate in low densities and most are over exploited for traditional Chinese medicine or other usages. Genus Hippocampus is listed on Appendix II of CITES but the majority of seahorse species are listed as data deficient. Consequently, it was critical to characterize the spatial distribution for effective species management.  

The investigation of population structures of H. mohnikei in north China sea areas including Bohai Sea and Yellow Sea suggested that this species expressed localized active dispersal directed toward offshore migration for overwintering and they were most abundant in Laizhou Bay during warm seasons. The continuous surveys with a total of 27202 individuals collected on H. mohnikei in Laizhou Bay were finished to identify the genetic structure and temporal variation. The population of H. mohnikei aggregated in a large scale during May to October with peak values observed in July and August. Typical breeding population of H. mohnikei were described in Laizhou Bay during warm seasons. Most of the captured seahorses were in matured stage with developed ovaries in females and an average pregnant percentage of 34.7±14.6% in males (Fig. 1). Active courtship and competitive behavior in seahorses were observed during the summer.

This research demonstrates that H. mohnikei aggregated into Laizhou Bay for breeding in large population during warm season and overwintered by local migration to offshore areas.

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