Little by little, we have been disclosing the wonders that hide seas and oceans of the world: cetaceans, sharks, jellyfishes, starfishes, marine turtles, nudibranchs, pyrosomids, ctenophora, coral, among others. Today we will know a little bit more about some animals with a curious shape: seahorses.
Seahorses, together with pipefishes and the leafy, ruby and weedy seadragons, constitute the Syngnathidae family. They are small fishes with a long body, which present a unique feature: females lay the eggs inside a pectoral cavity of male, where are fecundated, and then they are released. Watch this video of a male seahorse realising the small seahorses:
These animals live in coastal waters of tropical and subtropical seas, what include Mediterranean sea, mainly in algae and Posidonia. In the Mediterranean, we can find three genus of Syngnathidae: Hippocampus, Syngnathus y Nerophis; but here we will focus on the first one, which corresponds to seahorses.
Seahorses, which use the tail like a tiller and to hold on to objects, maintain their vertical position thanks to an organ that allow their buoyancy called swim bladder (present in all fishes) and the tail. All seahorse species are included in the genus Hippocampus, with about 50 species. They feed on small invertebrates, mainly crustaceans present in the plankton. When the prey is close, its mouth acts as a hoover.
In the Mediterranean, we find two species of seahorse: the short snouted seahorse (Hippocampus hippocampus) and the seahorse (Hippocampus guttulatus).
SHORT SNOUTED SEAHORSE (Hippocampus hippocampus)
The short snouted seahorse, with a brown grey colouration, present a short snout and they lack appendixes in the head and back. They can measure 15 cm. They live in sandy and detritus sea-floors till 10 m deep. When a female wants to introduce the egg mass inside the male, they do not hold on each other. Males release the little seahorses after 4 weeks. Their conservation status is unknown.
SEAHORSE (Hippocampus guttulatus)
This seahorse, different from the other one, presents long snout and abundant appendixes in the head and trunk. They can also measure 15 cm long. They usually live in seagrasses, but is quite difficult to see them. In this case, the male and the female hold on to each other when she wants to introduce the egg mass in the male. Its conservation status is also unknown.
- Ballesteros y Llobet (2015). Fauna i Flora de la mar Mediterrània. Ed. Brau
- Club de Inmersión de Biología: Hippocampus hippocampus
- Club de Inmersión de Biología: Hippocampus guttulatus
- IUCN: Hippocampus guttulatus
- IUCN: Hippocampus hippocampus
- Martin (1999). Claves para la clasificación de la fauna marina. Ed. Omega
- Riedl (1986). Fauna y Flora del Mar Mediterráneo. Ed. Omega