Reply To: Seahorse Courtship

Dear Anna:

Yes, it sounds like your Hippocampus erectus are definitely displaying a healthy interest in courtship and mating.

Males will perform such displays when they are trying to attract a mate during initial pair formation, as the morning greeting once a pair bond has been formed (this daily greeting ritual lasts only a few minutes, and is usually conducted in the very early morning, right at the crack of dawn), and, of course, when the actual mating is occurring.

In this case, Anna, it sounds like your Hippocampus erectus are already a couple and that they are now getting very serious about mating, which is clear because the female is also rising to the surface, not just your stallion, trying to entice the female to join him.

Your ponies are ready for the exchange of eggs, which takes place when the couple rise together and the female transfers her eggs to the pouch of the male, but this is a very complex, tricky maneuver to pull off successfully, and it often takes inexperienced couples many false starts and botched mating attempts before they finally get everything right. It’s not unusual for eggs to be spilled, or even the entire clutch of eggs to be dropped, so it’s very difficult to say how long it will take your pair of seahorses to accomplish their goal.

One thing I can tell you is that once the eggs have been transferred successfully to the male, he will make no more rises until he has delivered his brood of babies, assuming he is able to carry them full term. However, once he delivers his brood of young, the female will have a new clutch of eggs ready for him, and they will often re-mate that very same day.

Here is some additional information explaining what to expect at this point in the proceedings, Anna:

Copulatory Rise.

This is the final phase of courtship. It is the climax of the entire affair during which the partners meet in midwater for the transfer of the eggs (Vincent, 1990). The female initiates the rise by pushing up from the bottom in mid-Point and the male immediately follows her lead. They ascend through the water column facing each other, with their heads raised high and their abdomens thrust forward (Vincent, 1990). At this point, the female’s genital papillae or oviduct will be everted and protrude slightly from her vent, and the male’s brood pouch is usually fully inflated (Vincent, 1990). As they ascend, the female often continues to Point and the male may continue to Pump (Vincent, 1990). They will meet at the apex of their rise for the nuptial embrace.

The actual transfer of eggs takes place while the couple is suspended in midwater or slowly descending toward the bottom — a maneuver that is every bit as tricky as it sounds. Coitus is marked by an extremely awkward, fleeting embrace, aptly described as little more than a brief belly-to-belly bumping (Vincent, 1990). (Brief and fleeting as in if one dares to blink, take a bathroom break, or run for your camera you may miss what you have waited all this time to witness!) As you can imagine, many difficult and delicate maneuvers are required to bring the pair into proper position for this most improbable merging. The female will attempt to insert her oviduct into the gaping aperture of the male’s inflated brood pouch. An inexperienced pair will often end up misaligned, perhaps at right angles to one another or with one of the partners too high or too low to join. This is very typical of the many false starts and abortive attempts that are ordinarily involved. The frustrated couple will separate to rest on the bottom prior to successive attempts. They may require many such rises before the proper positioning is achieved and the crucial connection is finally made.

The female will eventually succeed, with the full and active cooperation of her mate. He positions himself slightly below his mate, with the aperture of his pouch fully dilated and gaping open, ready to receive her eggs. The female will hover directly over the aperture until she can actually insert her oviduct into the opening at the top of his brood pouch or drop her eggs into the basket while hovering directly above the pouch. Pairs occasionally entwine tails when joined, but more often than not their tails will be stretched back behind them, out of the way.

If she makes a good connection, she will extrude her eggs in one long, sticky string, and the pair will hang together in midwater while the transfer is completed, drifting slowly downward as the eggs surge downward deep inside the pouch (Vincent, 1990). The entire clutch — up to 1600 eggs — is transferred in one brief embrace lasting a mere 5-10 seconds (Vincent, 1990). Sperm stream from the male’s urogenital pore into the pouch opening as the eggs are deposited (Vincent, 1990). The couple separates as they descend, drifting slowly toward the substrate. Exhausted by their efforts, the pair seek out comfortable hitching posts for a well-deserved rest. One almost expects to see them light up cigarettes at this point.

The pregnancy-sustaining changes in the male’s pouch begin the moment the last egg is tucked safely away inside this protective pocket. The male’s pouch deflates, compressing the eggs against the pouch lining in order to facilitate implantation. The male then perches and attempts to settle the eggs properly in his pouch, often undergoing a series of agitated contortions, swaying, twitching, or wagging his tail from side to side, and perhaps stretching as though trying to rearrange the eggs more comfortably (Vincent, 1990). He is dispersing the eggs uniformly throughout his pouch, giving each one the best chance to be fertilized and implant in the septum or wall of the marsupium.

Meanwhile, the female’s belly slims down noticeably as she transfers her eggs. She may lose up to 30% of her body weight after depositing a large clutch of eggs (Vincent, 1990). As a result, her abdominal plates or belly rings will be concave or pinched in for the next couple of days.

The seahorse’s charming courtship rituals and delightful displays are a wonder to behold. The grace and beauty of the courtship dance, with its carousel-like ballet and elegant parallel promenade, the rhythmical swaying and passionate performances of “Pointing” and “Pumping,” and the fabulous midwater finale all combine to create an unforgettable spectacle that’s unprecedented in all of nature.

Enjoy the show while it lasts, Anna.

Happy Trails!
Pete Giwojna, Ocean Rider Tech Support