Staff members of the Department of Russian Far East Marine Species received a present before the New Year. On 18th December, early in the morning, the fishkeepers found a small school of newly hatched pups in an aquarium with spiny dogfish, or spurdog sharks, Squalus acanthias. They put the hatchlings into a smaller aquarium and started nurturing them with love and care.
The aquarists had been observing courtship and other types of mating behavior in dogfish many times before. “Gentlemen” usually chase “ladies” in a quite aggressive manner. As a result, the fins of females are often torn, and the noses scratched.
However, it happened for the first time not only at the Primorsky Aquarium, but in Russia, that the spiny dogfish mating eventually ended in the emergence of the offspring. Gestation lasts long in this ovoviviparous species, normally from 12 to 24 months, and the aquarists had been observing the behavior and physical conditions of the females for a year. The fact that the young were born so soon was a pleasant surprise.
The adult dogfish arrived in the Primorsky Aquarium six years ago. They were caught as a bycatch by a seiner targeting walleye pollack. Luckily, there were members of the Primorsky Aquarium’s team on board, and they managed to safely remove several spurdog sharks from the trawl and to transport them to their new home.
The fish have adapted well to the Aquarium’s environment and got accustomed to regular interactions with people. On seeing their “mom”, Senior Specialist Natalia Krymskaia, they come to the surface and poke their noses above the water to receive caresses. Natalia says that the sharks enjoy being stroked and sometimes ask for food just like pets. Their diet is diverse: fish (chum salmon and walleye pollack), mollusks, and crustaceans.
First, the aquarists fed the newly hatched dogfish twice a day with small pieces of salmon threaded onto special sticks. Now, they can eat without any assistance and take food from the bottom of the aquarium. Their appetite is really hearty!
“Spiny dogfish are quite “slow”, says Andrei Telegin, Aquarium Curator. “According to some sources, they can live as long as 100 years and they do not grow up too fast. Nevertheless, we hope they will be large enough in about two years to be exhibited.”
The first generation of spurdog sharks is on display in the Bering Sea and Sea of Okhotsk exhibit, opposite the Kelp Forest tank.