NOAA Teacher at Sea
Onboard NOAA Ship Pisces
June 14 – July 2, 2010
Mission: SEAMAP Reef Fish Survey
Geographical Area of Cruise: Gulf of Mexico
Date: June 23, 2010
Weather Data from the Bridge
Time: 1000 hours (10 am)
Position: latitude = 27°51 N longitude = 093º 51 W
Present Weather: 7/8 cloudy (cumulus/cirrus clouds)
Visibility: 10 nautical miles
Wind Direction: SSE Wind Speed: 8 knots
Wave Height: > 1 foot
Sea Water Temp: 31°C
Air Temperature: dry bulb = 31.4°C, wet bulb = 28°C
Science and Technology Log
Because of the oil spill in the Gulf of Mexico, most of the fish we are catching in the Chevron Trap or Bandit Reel is being weighed, measured, and frozen for the National Seafood Inspection Laboratory (NSIL) to be tested for oil or toxin contamination. After the NSIL completes its testing, the fish are sent back to the NOAA Pascagoula Laboratory where the scientists determine the sex of the fish and remove the otolith, or ear bone, which can be analyzed to determine its age. The otoliths are sliced very thin and examined under a microscope. Rings can be seen that help the scientists age the fish, similar to reading tree rings to determine the age of a tree. Age data is analyzed to contribute to the fishery-independent stock assessments which help determine the health of the fish population and how many can be taken out of the water. This also helps establish the size restriction of fish for the commercial and recreational fishing industry.
Occasionally, the fish trap will catch more than 10 fish at a time. If this happens, the first 10 fish are frozen for NSIL. Any remaining fish are dissected on board the ship to determine their sex and their otoliths are removed and placed in a labeled envelope for later analysis. The picture above shows the otoliths taken out of a red snapper.
The video footage taken at each station will also be analyzed in depth back at the NOAA Pascagoula Laboratory; however after each station, the footage is spot checked to ensure that the cameras recorded properly. The scientists make sure that the cameras are positioned correctly and not pointing upward in the water column or down on the ocean floor, that the field of view is not obstructed by an object like a rock, and that the water is clear enough to view the fish in sight. When we first began the Reef Fish Survey, most of the fish we saw were red snapper. As we have moved up in latitude toward the Flower Garden Banks Marine Sanctuary, the diversity of fish has increased.
There are 14 federally designated marine sanctuaries in the United States and the Flower Garden Banks is the only one located in the Gulf of Mexico. The Banks are essentially three large salt domes that were formed about 190 million years ago when much of the Gulf evaporated into a shallow sea. When the salt deposits were covered in layers of sediment, the pressure and difference in density caused the salt domes to rise and corals began to form on them about 10,000 to 15,000 years ago. (This information was obtained from the Flower Garden Banks Marine Sanctuary website. For more information, visit this informative and interesting website at http://flowergarden.noaa.gov )
Most of the fish we catch in these waters seem to be Red Snapper. We have also seen a variety of groupers including the giant Warsaw grouper, a Marbled Grouper, a Scamp Grouper, and a very rare Yellowmouth grouper shown in the upper left photo. We have also caught a few Grey Triggerfish shown on the right, Longspine and Red Porgies, Tomtate, Vermillion Snapper, and a very small and colorful Reef Butterflyfish.
As stated earlier, we do not view the entire recording from the camera arrays, but as we were spot-checking the footage from one of the cameras, one of the scientists came across an image of the Marbled Grouper that was later caught in the bandit reel. Looking closer at the image shows the variety of species found in these coral reef ecosystems including a Squirrelfish, a Yellowfin Grouper that has spots resembling a cheetah, and to our delight, a Spotted Moray eel!
I was amazed that fish could be aged by the rings in their ear bones! I watched one of the scientists extract the otiliths from a snapper and it was real work! Chief Scientist, Paul Felts, explained that the age of sharks can be determined by growth rings found in their vertebrae. Sometimes when they catch sharks, scientists inject a dye into the spines of sharks. This makes their growth rings more easily seen. Then they quickly tag the sharks and release them again into the ocean. If these sharks are ever caught again by NOAA, scientists could get new measurements and determine survival data.
Another interesting fact about sharks has to do with blood in the water. Most people know that blood attracts sharks. However, if you cut open a shark and throw it into a group of sharks, the other sharks scatter. Seems like they don’t like the smell of shark blood.
I love watching video of the fish at the Flower Garden Banks Marine Sanctuary. I’m fascinated seeing the variety of fish as they swim by and I really like to see them “kiss” the camera. It’s a whole different world down there.
Otolith – ear bone,
NSIL – the National Seafood Inspection Laboratory
Flower Garden Banks Marine Sanctuary – only sanctuary in the Gulf of Mexico
“Did You Know?”
Did you know that sharks aren’t always able to digest what they eat. I guess it’s hard to digest a can or a boot. Well, if that happens, the shark will either vomit or turn its stomach inside out.
Spotted Moray eel