10/24/05
Bryan, a third grader from Randolph county, wonders if you have seen any jellyfish.
On the surface we have seen and collected Portugeuse Man-of-War. This jellyfish has a bright purple gas-filled
sac that acts as a sail. Underneath the sail there are long tentacles with stinging cells. When we dive in the
sub, we frequently see comb jellies. Comb jellies aren't really jellyfish, but are Ctenophores, and generally
don't sting. Comb jellies are shaped like eggs and have rows of cilia, or tiny hairs. The tiny hairs beat together
and make the comb jelly move.
Angel, a third grader from Randolph county, wants to know if you have seen any sawfish.
We have not seen any sawfish. These animals generally stay in shallow tropical waters and sometimes travel into freshwater.
They are related to rays and we have seen a few different types of rays and skates.
Jayson, a third grader from Randolph county, asks if you have seen any barracuda.
We have not seen any barracuda. Generally barracuda live in tropical and other warm waters. They are usually seen closer to shore as well.
Anne-Marie from Tennessee wonders:
How do deep-water creatures navigate without light?
There is extremely limited light provided by bioluminescent organisms in the deep ocean, so many animals
have very big eyes to capture whatever light is available. Many also use chemoreceptors to navigate and
search for food. Chemoreception works a lot like the sense of smell. We use cat food in traps to catch
crabs and have actually watched crabs scurrying over to the traps as soon as we put them down which suggests
that the crabs "smell" the bait.
How do the creatures react to light?
Some of the fish appear to be blinded by our lights, much like people are when they emerge from a dark theater
into bright sunlight. Fish usually swim away as we approach in the sub.
Tatiana, a ninth grader from Wake county, wonders if you have caught any angelfish.
We have not caught any angelfish. Angelfish usually live in warm shallow waters such as on tropical and subtropical reefs. We
would be quite surprised to find angelfish in waters this deep.
