Lined Seahorse - Reproduction

Reproduction

Like all species of seahorses, the lined seahorse reproduces sexually, laying eggs every season. In addition, the male is the parent that looks after the newborn seahorses. The reproduction process begins at the initiation of the courtship process. Courtship extends for a couple of days and during this process, both the male and female may change to a pale color. The male enlarges his pouch to indicate his desire to pursue the female. Once they are established as monogamous mates though dances and clicking sounds, intercourse takes place.

During intercourse, the female sprays her eggs into the males pouch, which is called a "brood pouch", where they are fertilized and sealed. Females clutch size can be equal to or greater than one thousand and the males' brood size can range from 97 to 1,552 eggs. The number of eggs the female produces varies depending on the size of the seahorse. Six hundred and fifty eggs can be carried by a single male at one time. The eggs are 1.5 mm in diameter. When the eggs are being incubated within the male's pouch, the embryos are provided oxygen via an extensive capillary system. Through this system, the sodium and calcium levels can be altered in order to maintain homeostasis within the pouch environment. When the embryos are approaching birth, the pouch environment is very similar to the seawater. The gestation period lasts for 20–21 days. When the time finally approaches, the male latches his prehensile tail onto a supportive object while he braces back and forth, until the developed seahorses escape from the pouch. The bracing continues until all seahorses have successfully escaped the pouch. However, unhatched seahorses that have died will create a gas within the male's pouch. Soon after, the male seahorse inevitably floats to the surface, only to become easy prey in the marine food chain.

Juveniles are approximately 11 mm at birth for three days and are considered embryos until they are capable of swimming on their own. Juveniles do not reach maximum size until they are 8–10 months of age. It is estimated by scientists that only about two juveniles grow up to be adults out of the hundreds that are hatched. In captivity, the species maintained a vertical growth rate of 0.55 mm a day for 100 days. Male juveniles develop pouches when they are 5–7 months old. The juvenile seahorses quickly develop the characteristic of the adult lined seahorse. After birth, courtship begins once again. Breeding occurs in the months of May through October in the Chesapeake Bay. July is when the lined seahorse population is the greatest in Florida.