Reproduction and Development of the lined seahorse
Reproduction
Lined seahorse reproduce sexually through internal fertilization. Sexual reproduction requires two parents, a male and a female, traits are combined from both and offspring are not an identical copy of either parent. Male and female lined seahorses are sexually different. While females produce eggs, males have an incubation pocket or brood pouch on the lower side of the tail where the eggs develop and the embryos are carried until birth. Most unusual, males get pregnant and give birth!
Lined seahorses are sexually and socially monogamous—most mate with one partner for life. Mating takes place between May-August. Courtship can last for a few days and includes daily visits and dancing, clicking, tail wrestling, and snout snapping rituals between males and females. Males inflate their pouch and pursue the female to show they are ready to mate. Both males and females change color and become pale or whitish during mating. Mating ends with the female depositing between 250-650 eggs to the male brood pouch. The average diameter of an egg is 1.5mm. Males seal the pouch and release sperm to fertilize the eggs. The brood pouch protects the embryos and provides nutrients and oxygen. It also regulates the salinity changing the concentration until it is similar to seawater prior to birth.
Meiosis creates the lined seahorses egg and sperm cells (gametes). In meiosis, the number of chromosomes are reduced by half producing four haploid cells. The lined seahorse chromosome haploid number is 24. Like all organisms, lined seahorses use mitosis for cellular reproduction and growth.
Lined seahorses are sexually and socially monogamous—most mate with one partner for life. Mating takes place between May-August. Courtship can last for a few days and includes daily visits and dancing, clicking, tail wrestling, and snout snapping rituals between males and females. Males inflate their pouch and pursue the female to show they are ready to mate. Both males and females change color and become pale or whitish during mating. Mating ends with the female depositing between 250-650 eggs to the male brood pouch. The average diameter of an egg is 1.5mm. Males seal the pouch and release sperm to fertilize the eggs. The brood pouch protects the embryos and provides nutrients and oxygen. It also regulates the salinity changing the concentration until it is similar to seawater prior to birth.
Meiosis creates the lined seahorses egg and sperm cells (gametes). In meiosis, the number of chromosomes are reduced by half producing four haploid cells. The lined seahorse chromosome haploid number is 24. Like all organisms, lined seahorses use mitosis for cellular reproduction and growth.
Courtship (dancing) Male inflating brood pouch Female depositing eggs
Male sealed brood pouch Male full brood pouch Male giving birth
Male sealed brood pouch Male full brood pouch Male giving birth
Development
Lined seahorse average gestation period is 20-21 days. Males give birth to “fry” over about 3 days. Newborns are released by ejection from the brood pouch by body contortions and pumping action of the pouch. Young or “juveniles” are about 11mm in length and tiny copies of the adults. They can feed and defend themselves immediately. Within 5-7 months they reach adult size and sexual maturity. Life expectancy is between 1-4 years. The lined seahorse stages of development are zygote, embryo, newborn, juveniles and adult. A pair of seahorses can produce around 1000 young each year but there is a high mortality rate - usually more than 90% die. Females do not play any role in parental care. Neither males nor females nurture their young after birth.