Published June 2005
Dear Sea Scoop!
Is it true that the male seahorse carries baby seahorses during gestation?
-Dave Mciver, St. Thomas, VI
Dear Sea Scoop!
Is it true that seahorses mate for life?
-Jessica Hendy, St. Thomas, VI
Dear Jessica and Dave
Seahorses are bony fish belonging to the family Sygnathidae (sig-NA-thih-day) along with pipefishes, pipehorses and sea dragons. Seahorses are all in the genus Hippocampus from the Greek meaning horse-like sea monster because their heads are shaped like that of a horse.
One of the many remarkable things about seahorses is the fact that the male is the one that carries the fertilized eggs until they are ready to be born. The process begins with an intense mating dance, during which both the male and female change color and sway and move together, sometimes entwining their tails. This lasts for several minutes and culminates with the female depositing her eggs into the male's brood pouch through her ovipositor (oh-VIH-Pah-zit-or, a specialized organ used for depositing eggs). Once deposited inside the pouch, the male fertilizes the eggs. The pouch absorbs the fertilized eggs and provides them with nutrients and oxygen, and processes their waste products as the embryos develop. After a 2-4 week gestation period, the male begins to release the juvenile seahorses. In an act that's a lot like labor, the male thrusts and pumps the brood out of the pouch, releasing between 100-200 babies.
There are many different species of seahorse and most of them are monogamous (mah-NAH-gah-muss, meaning they have only one mate), although it is generally not for life. During the breeding season the female and pregnant male pairs will bond together with a daily greeting ritual. This ritual is similar to the mating dance, but for a shorter duration. After the dance is completed, the female swims away and they separate for the remainder of the day. This greeting dance is suspected to play a role in mating-pair bonding and ensure that they are both ready to mate again, after the males releases the young.
According to the 2004 World Conservation Union (IUCN) Red List of Threatened Species, 10 species of seahorses are considered vulnerable and one is listed as endangered. All other species are listed as "Data Deficient" meaning that not enough is known to determine their status. Seahorses are exploited for use in home aquariums, as souvenirs, and in health tonics. In addition, human destruction of seahorse habitats such as coral reefs, seagrass beds, mangrove forests and estuaries is having an impact on the health of seahorse populations. What can you do to help? First of all, resist the temptation to have seahorses in your home aquarium unless you have extensive knowledge and experience. Seahorses are very difficult to keep alive in captivity because they must have live food and they are also susceptible to many diseases. If you decided that you must have one, make certain it was captured in a sustainable manner and do not purchase a pregnant male. Try not to buy souvenirs that contain dead seahorses. As attractive as they look in a necklace or paperweight, they are far more beautiful living in their real habitat in the sea. If you use seahorses in health tonics, see if there are other, more sustainable alternatives. Finally, learn what you can do to prevent marine habitat destruction and promote marine conservation. The health of our marine environment is everyone's responsibility.
For more information on seahorses:
Nova Online "Kingdom of the Seahorse"
Science News Online "Pregnant and Still Macho"
For information on the IUCN Red List of Threatened Species:
For more information on marine conservation:
The Ocean Conservancy
Marine Conservation Biology Institute
The Nature Conservancy Marine Initiatives
Have a question about the world beneath the waves? Write it down and send it to Sea Scoop! Please remember to include your name and where you're from.
For more information on marine science in the Virgin Islands, visit the University of the Virgin Islands' Center for Marine & Environmental Studies.
Elizabeth Ban is the University of the Virgin Islands Marine Adviser for St. Thomas and St. John. She works to inform and educate citizens about ocean resources and promote coastal ecosystem health. She is based at UVI's Center for Marine and Environmental studies on the St. Thomas Campus. For more information about UVI's Marine Advisory programs, please call 340-693-1392.
Sea Scoop! #8: All About Seahorses!
Published June 2005
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