Dear Grant:
How soon your female will be ready to ripen another clutch of eggs depends on when she last mated. If there was a successful egg transfer about two weeks ago, then it may take another week or two before she is ready to mate again. Females normally only ripen one clutch of eggs each breeding cycle, and for Mustangs and Sunbursts (Hippocampus erectus), a mating cycle is typically about one month or a little less.
If there was not an actual mating two weeks ago, and your stallion was simply displaying with a ballooned pouch full of water rather than carrying eggs and developing young, then your female could ripen another clutch of eggs at any time.
Seahorses are fractional spawners and very well adapted for producing clutch after clutch of eggs. Females maintain a spiraling assembly line of developing oocytes (egg cells) at all times, only a portion of which are fully mature and are released at each mating (Vincent, 1990). This differs from the reproductive strategy of most fishes, which are multiple spawners that release all their eggs each time they mate and then start over, maturing an entirely new clutch of eggs from scratch for the next spawning.
The structure of the ovaries is unique to syngnathids. They are paired organs, which join to form a single oviduct (the seahorse’s version of a Fallopian tube) just before the urogential pore (Vincent, 1990). Oocytes spiral out from the center of each ovary, creating a coiled sheet of developing eggs at differing stages of growth (Vincent, 1990). The earliest or primordial eggs arise from the germinal ridge that runs the entire length of the ovary, and lie at the center of the coil from which they spiral out as they develop so that the fully mature eggs are the furthest from the center of rotation (Vincent, 1990). Roughly 20-25% of the outermost eggs in this ovarian assembly line are mature, ready to be discharged during ovulation and deposited with the male (Vincent, 1990). Thus, fully 70-75% of the female’s developing eggs are retained in the ovaries after mating, so a new clutch of eggs will mature relatively quickly and lie in readiness for the next mating cycle.
Seahorse ovaries are always active, busy creating and developing new eggs (oogenesis), forming the yolk (vitellogenesis), and resorbing any mature ova (atresia) leftover after mating or at the end of the breeding season (Vincent, 1990). Eggs in all 4 stages of development can be found in the ovaries throughout the year.
So if your female has not mated recently, Grant, her ovarian assembly line has mature eggs ready and waiting right now and she could hydrate them and mate successfully at any point — today, tomorrow, even right at this moment. But if your pair of seahorses did indeed mate two weeks ago, she will need another week or two for the outermost eggs in the queue to mature fully before she can mate again.
Best wishes with all your fishes, Grant! Here’s hoping that your new seahorses produce a healthy brood of young for you very soon.
Happy Trails!
Pete Giwojna
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.
