Seahorses!

Reproduction in seahorses:

SEAHORSES are part of the family syngnathidae (‘sing-nath-i-dee), which means, “fused jaw”. All seahorses, nearly 50 species, belong to the genus Hippocampus. As in most organisms, the reproductive system of the seahorse consists of tubular testis and duct system that do not possess an external copulatory organ. Males do however, employ an anal fin, which is situated just above the opening of the pouch and helps to direct the ovulated eggs into the pouch. The anal fin also directs sperm released by the urogenital duct towards the mature eggs as they travel from the female to the males brood pouch. Because the brood pouch plays no direct role in fertilization, as it is anatomically separated from the reproduction system, the pouch is considered a secondary sex characteristic.

Birth

     The males are pregnant for several weeks before giving birth to their brood (Vincent, et. al 1992).  When they prepare to give birth, the pouch extends to an almost spherical shape.  The male also undergoes muscular contortions - a forward and a backward bend - that last for about ten minutes.  then in an explosive action the brood leaves the pouch.  After the last young sea horse has left, the pouch returns to its normal position, which usually takes about an hour (Breder 1940).  Males are ready to re-mate within a few hours of giving birth (Vincent, et. al 1992).