Because of high demand for seahorses and the decline of wild populations, new opportunities for aquaculture are beginning to be exploited. At present there are only a few farms in Europe, a commercial farm in Tasmania, another on the Gold Coast, Queensland, and one in New Zealand. 

In New Zealand, research into seahorse farming began in response to known heavy fishing effort which was dramatically affecting wild populations of certain species. [1]

Source

1. Marine Conservation Society (UK) SouthEast