The NC Aquarium
at Fort Fisher is home to thousands of fish and many people wonder where they
all come from. There are many different ways the Husbandry staff populates
exhibits. We are often asked if we raise our own fish, and the answer is yes. Fort
Fisher staff is researching and working on new ways to grow fish from egg to
adult within the Aquarium.
While
on exhibit, animals ideally show natural behaviors which often involve laying
eggs. There are three main ways fish reproduce. Some fish are bearers, when
one parent internally carries the eggs through development. Others are demersal
spawners, laying eggs in a nest and guarding them until they hatch. Lastly, pelagic spawners release
millions of eggs to be fertilized as they flow though the ocean. Many
aquariums, including Fort Fisher, have succeeded in raising the larvae and fry
(baby fish) from bearers and demersal spawners, like our amazing seahorses,
small neon gobies and stingrays. However, the majority of Aquarium fish are
pelagic spawners. There are many opportunities to raise fish going (literally)
down the drain.
Recently,
we began a project to collect and raise some of these free-floating eggs. The
healthy, fertilized eggs float to the top of the water. Specially built
collecting equipment skims the top layer of water, collecting hundreds, and
sometimes thousands, of eggs.
Larval rearing system at NCAFF |
Pelagic eggs hatch within 24 hours from being released. When
the eggs hatch, the larvae are very small and undeveloped. A special holding tank was developed to keep
them gently moving as if in the ocean currents. Initially, there is no need to
be concerned about food because the larvae have no mouths. Instead, they feed
from an attached yolk for the first few days. When they begin eating, things get
a little tricky. Fish larvae are picky eaters. The food has to be the right
type, size, and even speed for them to go after it. They survive mostly on
algae and copepods (tiny crustaceans).
Juvenile blue striped grunt from eggs collected in April |
It takes a lot of trial and error
to hatch and grow the pelagic eggs. So far, the Fort Fisher Husbandry staff has
had success with blue striped grunt; collecting eggs from our largest exhibit, the
Cape Fear Shoals, and raising the fish behind the scenes. We have collected
many types of eggs from the Shoals and other exhibits. Each attempt moves us
closer to a goal of raising more fish in a sustainable
way at the Aquarium.