NOAA Teacher at Sea
Lesley Urasky
Aboard the NOAA Ship Pisces
June 16 – June 29, 2012
Mission: Caribbean Reef Fish Survey
Geographical area of cruise: St. Croix, U.S. Virgin Islands
Date: Saturday, June 16, 2012
Location:
Latitude: 17.6395
Longitude: -64.8277
Weather Data from the Bridge:
Air Temperature: 29°C (84°F)
Wind Speed: 15.76 knots (18.1 mph)
Relative Humidity: 79%
Barometric Pressure: 1,012.7 mb
Surface Water Temperature: 29°C (84°F)
Personal Log
My trip to meet the Pisces and become a Teacher at Sea was a two-day process. I traveled from my home in Sinclair, Wyoming to Denver, Colorado to catch the first of three flights. The first flight was from Denver to Dallas/Ft. Worth International Airport; after a two-hour layover, I then flew to Miami. Originally, I was to travel the entire way in one day. However, I didn’t want to arrive in St. Croix at 10:00 p.m. and have to make my way to the pier, pass through security, board the ship, find my stateroom, and hopefully meet some of the crew and scientists late at night. Instead, I spent the night in Miami and flew to St. Croix the next morning.
Once I landed at the Frederiksted Airport on St. Croix, I took a taxi to the cruise ship pier. The taxi driver was very concerned about taking me there, because no cruise ships were docked; he was doubtful that any ship was there. After convincing him that a NOAA ship was indeed docked, he moved aside the sugar cane in the back, loaded my bags, and took me to the pier. Breaking my trip into two pieces turned out to be the best plan because once I got to the security gate, there was no approved members list at security and they wouldn’t accept my travel document. They called the ship and the Commanding Officer (CO) came down the pier to meet me at the gate and escort me to the ship. After a quick tour of the ship, I took some time to settle into the stateroom I’m sharing with the Operations Officer, Kelly Shill. The rest of the afternoon was spent exploring Frederiksted.
On Friday, June 15th, I went to Christiansted with some of the ship’s crew members. Kelly Schill, Operations Officer; Chris Zacharias, Junior Engineer; Peter Langlois, 3rd Mate; and I went shopping for souvenirs, had lunch, and fed the resident school of tarpon outside of Fort Christian Brew Pub. Later that evening, we went to a beachside restaurant and watched a performance by some modern dance fire dancers.
Today we left port and embarked on the third Leg of the Caribbean Reef Fish Survey. The first leg was when the Pisces traveled from Pascagoula, Mississippi to San Juan, Puerto Rico; here the ship picked up the scientific crew. The second leg was from San Juan, Puerto Rico to St. Croix; during this time period, they collected data about the ocean and the fish along the reef system. I joined the scientists and crew of the Pisces at Frederiksted, St. Croix in the U.S. Virgin Islands. The Pisces was in port at St. Croix for three days for personnel change, resupply of the galley, and to give the crew a rest. During this leg, we will be traveling back to San Juan, Puerto Rico taking samples around St. Croix and St Thomas islands. In addition to the reef fish survey, the Pisces will be deploying the base (anchor and chain) for another buoy to collect oceanographic data 3 nautical miles (nm) south of Saba, which is located between St. Croix and St. Thomas. The University of Virgin Islands is working in conjunction with NOAA to accomplish this goal. Once back in San Juan, the scientists will leave the ship, returning home with the data. On the fourth leg, the Pisces will return to Mayport, Florida, retrieving a buoy that is adrift along the way. Commander Fischel is kindly allowing me to remain aboard during the cruise back to port!
Science and Technology Log
Here is a quick overview of all equipment the survey will use to collect data. There is an array of four video cameras that is baited with frozen squid. The array is lowered over the side of the ship at each sampling site, and allowed to rest on the bottom for 40 minutes. The cameras cannot be deployed during the night because there are no lights on the array. Therefore, viewing is dependent upon the availability of sunlight penetrating the water column. Because of the need for natural light, the cameras are only used during daylight hours; the array cannot be deployed earlier than one hour after sunrise and must be retrieved from the bottom of the continental shelf or shelf edge one hour before sunset.
After the camera array is deployed, a cluster of instruments called a CTD is lowered to collect data on the ocean environment. CTD is an acronym for Conductivity, Temperature, and Depth. Conductivity is used to determine the salinity (the amount of salts dissolved in the water). Water conducts electricity (this is why you shouldn’t use electrical appliances while in or around water, and why the lifeguard tells you to get out of the pool during a thunderstorm). As the salinity increases, conductivity increases. Temperature is a very straight forward measurement. I’m sure you’ve measured the temperature of several different things ranging from air temperature (to see how hot it is outside) to the internal temperature of a roasting chicken. These measurements are related to specific depths within the water column. The depth the instrument is at in the ocean is calculated from measuring the hydrostatic pressure (how much pressure the overlying water exerts on the instrument). The CTD instrumentation cluster collects huge amounts of data – 8 measurements per second! These are averaged and compressed into “bins” covering 1 meter segments.
In addition, the instrument cluster also measures the amount of oxygen dissolved (DO) in the water column. As you probably already know, most organisms require oxygen to live (carry out cellular respiration). The amount of oxygen dissolved in the water is directly correlated to how much life the water can support. More oxygen = more life. When water is warmer, it loses its ability to “hold onto” oxygen; cold water will contain more dissolved oxygen. This is one reason why climate change and warming aquatic environments are of great concern.
After both the camera array and CTD have been deployed and retrieved, the final step at each site is to collect fish through the use of bandit reels located at three sites on the ship. All three are located on the starboard (right hand) side of the ship. Reel #1 is starboard (S), Reel #2 is starboard aft (SA), and Reel #3 is starboard stern (SS) at the back of the ship. Reel #3 is where I helped the attempts to collect fish. Each bandit reel has ten hooks of the same size (8/0, 11/0, and 15/0) attached to a 300-lb test monofilament. Each of the hook sizes are rotated around the stations throughout the day. These hooks are baited with slices of frozen Atlantic mackerel. A 10 pound weight is attached to the end of the line, the baited hooks attached, and the line let out until it hits bottom. Then, a float is attached and the line is left for five minutes before being reeled back in.
Any fish that are caught are identified and have their length and mass measured. Afterwards, the fish’s otoliths are removed and it is opened to determine its gender and have its reproductive stage assessed. More on the fish specifics to come!