Secrets of the Black Sea: what is the fate of seahorse?

The long-snouted seahorse (Hippocampus guttulatus) inhabiting the Black Sea is an absolutely amazing creature. The body of this small fish is covered with horn-like plates and various outgrowths, which serve as natural camouflage and protect it from predators. The fish’s exoskeleton is quite sturdy, and does not lose its shape even if dried. Its unusual body shape and long-snouted head, indeed, make it look like a chess knight. In the 1960s it was easy to find this fish in shallow waters across almost all the Black Sea coasts and in the Kerch Strait, but eventually its exotic look became the reason for the almost total extinction of the population.

The seahorse leads a nearshore life and is not very mobile; for that reason, it was defenceless against predatory harvesting in the 1980-90s. Tens of thousands of specimens were dried annually to become souvenirs for tourists, and seahorses almost completely disappeared from sea areas located near resorts. That is why in 1994 it was listed in the Red Book of Ukraine and seahorse harvesting was prohibited. After these measures were taken, its population increased enough not to be listed into the next edition of the Red Book in 2009.

Seahorses belong to the syngnathidae family; their closest relatives are pipefish. But the difference is that seahorses swim upright nearly all the time. This ability is provided by the unique structure of its swim bladder, which is located along the seahorse’s body and is divided by a septum which separates its body from its head. The head swimming bladder is bigger than the abdominal one, and this helps seahorse to stay in a vertical orientation. Additionally, the seahorse can move its head up and down, which is a unique skill among fish. The reproduction process of seahorses is also rather peculiar. During spawning, they cling together using their flexible, finless prehensile tails. Then, the male seahorse opens a special brood pouch, which the female fills by laying up to one thousand eggs. A male seahorse broods the eggs, which eventually develop into juvenile fish. The newborn seahorses rise to the surface to take a first gulp of air, filling their swim bladders. Subsequently, they return to deeper waters and spend time with their father, hiding in its brood pouch in case of danger. Additionally, seahorses are real chameleons: like those of the reptile, seahorses’ eyes can move independently, providing it with a 300-degree viewing angle; furthermore, the seahorse can also change its colour, camouflaging itself among seaweed and stones.

Today, the prospects for seahorse populations are becoming more encouraging. Compared to the end of the last century, when this amazing fish almost completely disappeared from the North-Western part of the Black Sea, now it can be found even along the coast of Odessa. But people who are fond of Black Sea souvenirs should remember that the fate of the Black Sea depends not only on the condition of the marine ecosystem condition, but also on our wise conduct.

The publication was prepared with the financial support of the EU – UNDP project ‘Improving Environmental Monitoring in the Black Sea: Selected measures’ (EMBLAS-Plus). This publication was produced with the financial support of the European Union and UNDP. Its contents are the sole responsibility of the authors and do not necessarily reflect the views of the European Union or UNDP.

Authors: B. Aleksandrov, O. Adrianova, N. Atamas, V. Bolshakov, O. Bondarenko, I. Chernichko, V. Demchenko, S. Dyatlov, Y. Dykhanov, E. Dykyi, O. Garkusha, P. Gol’din, S. Hutornoy, V. Komorin, Y. Kvach, V. Mamaev, O. Manturova, O. Marushevska, A. Mikelyan, Yu. Mikhalev, G. Minicheva, I. Sinegub, T. Shiganova, J. Slobodnik, A. Snigiryova, M. Son, K. Vishnyakova, A. Zotov. Illustrator: I. Pustovar.