NOAA Teacher at Sea
Aboard the NOAA ship Pisces
June 16 – June 29, 2012
Mission: SEAMAP Caribbean Reef Fish Survey
Geographical area of cruise: St. Croix, U.S. Virgin Islands
Date: June 18, 2012
Weather Data from the Bridge:
Air Temperature: 28.5°C (83.3°F)
Wind Speed: 17.1 knots (19.7 mph), Beaufort scale: 5
Wind Direction: from SE
Relative Humidity: 75%
Barometric Pressure: 1,014.80 mb
Surface Water Temperature:28.97 °C (84.1°F)
Science and Technology Log
Alright, so I’ve promised to talk about the fish. Throughout the science portions of the cruise, the scientists have not been catching the anticipated quantities of fish. There are several lines of thought as to why: maybe the region has experienced overfishing; possibly the sampling sites are too shallow and deeper water fish may be more likely to bite; or they might not like the bait (North Atlantic mackerel) since it is not an endemic species/prey they would normally eat.
So far, the night shift has caught more fish than the day shift that I’m on. Today, we have caught five and a half fish. The half fish was exactly that – we retrieved only the head and it looked like the rest of the body had been consumed by a barracuda! These fish were in the grouper family and the snapper family.
Once the fish have been caught, there are several measurements that must be made. To begin, the fish is weighed to the nearest thousandth (three decimal places) of a kilogram. In order to make sure the weight of the fish is accurate, the scale must be periodically calibrated.
Then there are several length measurements that are made: standard length (SL), total length (TL) and depending on the type of fish, fork length (FL). To make these measurements, the fish is laid so that it facing toward the left and placed on a fish board. The board is simply a long plank with a tape measure running down the center. It insures that the fish is laid out flat and allows for consistent measurement.
Standard length does not measure the caudal fin, or tail. It is measured from the tip of the fish’s head and stops at the end of the last vertebra; in other words, if the fish is laying on its side, and you were to lift the tail up slightly, a crease will form at the base of the backbone. This is where the standard length measurement would end. Total length is just as it sounds – it is a measurement of the entire length (straight line) of the fish. Fork length is only measured if the type of fish caught has a forked tail. If it does, the measurement begins at the fish’s snout and ends at the v-notch in the tail.
Once the physical measurements are made, the otoliths must be extracted and the fish sexed. You’re probably anxious to learn if you selected the right answer on the previous post’s poll – “What do you think an otolith is?” An otolith can be thought of as a fish’s “ear bone”. It is actually a structure composed of calcium carbonate and located within the inner ear. All vertebrates (organisms with backbones) have similar structures. They function as gravity, balance, movement, and directional indicators. Their presence helps a fish sense changes in horizontal motion and acceleration.
In order to extract the otoliths, the fish must be killed. Once the fish has been killed, the brain case is exposed and peeled back. The otoliths are in little slits located in the underside of the brain. It takes a delicate touch to remove them with a pair of forceps (tweezers) because they can easily break or slip beyond the “point of no return” (drop into the brain cavity where they cannot be extracted).
Otoliths are important scientifically because they can tell many important things about a fish’s life. Their age and growth throughout the first year of life can be determined. Otoliths record this information just like tree ring record summer/winter cycles. More complex measurements can be used to determine the date of hatch, once there are a collected series of measurements, spawning times can be calculated.
Because they are composed of calcium carbonate (CaCO3), the oxygen component of the chemical compound can be used to measure stable oxygen isotopes; this is useful for reconstructing temperatures of the waters the fish has lived in. Scientists are also able to look at other trace elements and isotopes to determine various environmental factors.
The final step we take in measurement/data collection is determining the sex and maturity of the fish. To do this, the fish is slit open just as if you were going to clean the fish to filet and eat it. The air bladder must be deflated if it isn’t already and the intestines moved out of the way. Then we begin to search for the gonads (ovaries and testes). Once the gonads are found, we know if it is female or male and the next step is to determine its stage or maturity. This is quite a process, especially since groupers can be hermaphroditic. The maturity can be classified with a series of codes:
- U = undetermined
- 1 = immature virgin (gonads are barely visible)
- 2 = resting (empty gonads – in between reproductive events)
- 3 = enlarging/developing (eggs/sperm are beginning to be produced)
- 4 = running ripe (gonads are full of eggs/sperm and are ready to spawn)
- 5 = spent (spawning has already occurred)
Today is my birthday, and I can’t think of a better place to spend it! What a treat to be having such an adventure in the Caribbean! This morning, we were on our first bandit reel survey of the day, and the captain came on over the radio system, announced my birthday and sang Happy Birthday to me. Unbeknownst to me, my husband, Dave, had emailed the CO of the Pisces asking him to wish me a happy birthday.
We’ve had a very successful day (compared to the past two days) and have caught many more fish – 5 1/2 to be exact. The most exciting part was that I caught two fish on my bandit reel! They were a red hind and blackfin snapper (see the photos above). What a great birthday present!
Last night (6/17) for Father’s Day, we had an amazing dinner: filet mignon, lobster, asparagus, sweet plantains, and sweet potato pie for dessert! Since it was my birthday the following day (6/18), and one of the scientists doesn’t like lobster, I had two tails! What a treat!
Our best catch of the day came on the last bandit reel cast. Joey Salisbury (one of the scientists) caught 5 fish: 4 blackfin snapper and 1 almaco jack; while Ariane Frappier (another scientist) caught 3 – 2 blackfin and 1 almaco jack. This happened right before dinner, so we developed a pretty good assembly line system to work them up in time to eat.
Dinner was a nice Chinese meal, but between the ship beginning to travel to the South coast of St. Thomas and working on the computer, I began to feel a touch seasick (not the best feeling after a large meal!). I took a couple of meclazine (motion sickness medication) and still felt unwell (most likely because you’re supposed to take it before the motion begins). My roommate, Kelly Schill, the Operations Officer, made me go to bed (I’m in the top bunk – yikes!), gave me a plastic bag (just in case!), and some saltine crackers. After 10 hours of sleep, I felt much, much better!
I had some time in between running bandit reels, baiting the hooks, and entering data into the computers,to interview a member of the science team that joined us at the last-minute from St. Croix. Roy Pemberton, Jr. is the Director of Fish and Wildlife for the Department of Planning and Natural Resources of the U.S. Virgin Islands. The following is a snippet of our conversation:
LU: What are your job duties as the Director of Fish and Wildlife?
RP: I manage fisheries/wildlife resources and try to educate the population on how to better manage these resources to preserve them for future generations of the U.S. Virgin Islands.
LU: When did you first become interested in oceanography?
RP: I’m not really an oceanographer, but more of a marine scientist and wildlife biologist. I got interested in this around 5-6 years old when I learned to swim and then snorkel for the first time. I really enjoyed observing the marine environment and my interest prompted me to want to see and learn more about it.
LU: It’s such a broad field, how did you narrow your focus down to what you’re currently doing?
RP: I took a marine science class in high school and I enjoyed it tremendously. It made me seek it out as a career by pursuing a degree in Marine Science at Hampton University.
LU: If you were to go into another area of ocean research, what would it be?
RP: Oceanography – Marine Spatial Planning
LU: What is the biggest challenge in your job?
RP: It is a challenge to manage fisheries and wildlife resources with respect to the socioeconomic and cultural nuances of the people.
LU: What do you think is the biggest issue of contention in your field, and how do you imagine it will resolve?
RP: Fisheries and coral reef management. We need to have enough time to see if the federal management efforts work to ensure healthier ecosystems for future generations.
LU: What are some effects of climate change that you’ve witnessed in the reef systems of the U.S. Virgin Islands?
RP: Temperatures have become warmer and the prevalence of disease among corals has increased.
LU: In what areas of Marine Science do you foresee a lot of a career paths and job opportunities?
RP: Fisheries management, ecosystem management, coral reef diseases, and the study of coral reef restoration.
LU: Is there an area of Marine Science that you think is currently being overlooked, and why?
RP: Marine Science management that takes into account cultural and economic issues.
LU: What are some ideas a layperson could take from your work?
RP: One tries to balance resource protection and management with the cultural and heritage needs of the population in the territory of the U.S. Virgin Islands.
LU: If a high school student wanted to go into the fish/wildlife division of planning and natural resources, what kinds of courses would you recommend they take?
RP: Biology, Marine Science, History, Botany, and Math
LU: Do you recommend students interested in your field pursue original research as high school students or undergraduate students? If so, what kind?
RP: I would suggest they study a variety of life sciences so they can see what they want to pursue. Then they can do an internship in a particular life science they find interesting to determine if they would like to pursue it as a career.
Too many interesting people on the ship and so little time! I’m going to interview scientists as we continue on to San Juan, Puerto Rico. Once they leave, I’m continuing on to Mayport, Florida with the ship. During this time, I’ll explore other careers with NOAA.