Dear Tamy:
Oh, sure – Ocean Rider Mustangs and Sunbursts will happily breed at a water temperature of 75°F, Tamy. As I mentioned, the tropical seahorses at the Ocean Rider aquaculture facility are raised in natural seawater at a constant temperature of 75°F, and they breed like bunnies at the seahorse farm! Of course, this includes the ever popular Mustangs and Sunbursts, Ocean Rider’s strains of captive-bred-and-raised Hippocampus erectus seahorses.
In my experience, the photoperiod of the aquarium – the length of time the aquarium is lighted each day – has a much more profound effect on the breeding behavior of tropical seahorses in captivity than water temperatures within the range of 72°F-78°F or so. In a nutshell, seahorses breed best when provided with a photoperiod of at least 12 hours a day, and providing your ponies with significantly less light each day can inhibit breeding.
To understand why the photoperiod is so important for regulating breeding, we must first understand how the light-dark cycle regulates the levels of key hormones that control breeding. Gonadotropin (GtH) is a hormone that stimulates the growth and activity of the gonads and thus controls reproductive activity in vertebrates. It is secreted by the pituitary gland and stimulates the growth and function of the ovaries and testes. The levels of gonadotropin in the body are in turn regulated by melatonin, a hormone secreted by the light-sensitive pineal gland in response to darkness. Among a great many other functions, melatonin switches on a recently discovered enzyme known as gonadotropin inhibitory hormone, thus reducing the levels of gonadotropin in the body and shutting down reproduction (Sanders, 2005).
In other words, when the days are shortest and there is less sunlight, melatonin secretion is high and the levels of gonadotropin are reduced accordingly, causing the gonads to shrink and turning off reproduction. Likewise, when the days are longest and there is more sunlight, melatonin secretion is low and the levels of gonadotropin are high, stimulating the gonads and triggering reproductive activity (Sanders, 2005). So that’s something to keep in mind when you are hoping to curb the romantic tendencies of your Hippocampus erectus, Tamy – you need to make sure that the main tank is darkened enough to trigger the secretion of melatonin by the pineal gland in response to the hours of darkness. Keeping the aquarium illuminated for no more than 8-10 hours will usually do the trick.
On the other hand, if you want to encourage your seahorses to breed in a home aquarium, maintain stable water temperatures of 75°F-77°F and keep the aquarium light on for at least 12 hours a day for best results. If you maintain good water quality and provide your seahorses with a nutritious diet, and provide them with a suitable photoperiod, sooner are later, nature will do the rest and your Mustangs and Sunbursts will breed readily in the aquarium.
Respectfully,
Pete Giwojna, Ocean Rider Tech Support
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
