NOAA Teacher at Sea
Melinda Storey
Onboard NOAA Ship Pisces
June 14 – July 2, 2010
Mission: SEAMAP Reef Fish Survey
Geographical Area of Cruise: Gulf of Mexico
Date: June 15, 2010
Weather Data from the Bridge
Date: 6/15/2010
Time: 1000 hours
Position: Latitude: 27.38.1 N Longitude: 088.18.9 W
Present Weather: cloudy
Visibility: 10 nautical miles
Wind Direction: SSW
Water Temperature: 30.4 degrees Celsius
Air Temperature: 29.5 degrees Celsius
Ship’s Speed: 12.2 knots
Science and Technology Log
Today at around 1000 hours (10:00 am) our CO sighted a dead Sperm Whale from the bridge. Our scientists say it is extremely rare to see a floating sperm whale. In fact, a whale expert who communicated with one of our scientists said he has only seen one in 25 years of studying them! The Gulf of Mexico is a habitat of Sperm Whales. Females stay here year round and birth their young in these waters while male Sperm Whales travel to many different locations, some as far as the Antarctic Ocean. Sperm Whales are the deepest diving whales. Although they live at the surface, they dive to hunt Giant Squid that are bottom dwellers. They have been known to dive as deeply as 10,500 feet (3,200 meters) but average dives are about 4000 feet (1,200 meters) deep. The Sperm Whale can hold its breath for about an hour!
As you can see, the whale was covered in some black substance. Our scientists are not experts on marine mammals; however they spoke with Dr. Keith Mullin, the Southeastern Fisheries Science Center Marine Mammals Program manager, who stated that this is typical for the skins of dead whales to blister, char, and fall off. Upon seeing photos of the whale, the experts stated that it appeared to have died of natural causes; however we were asked to take samples from the whale to eliminate the possibility of oil as the cause of death. The ship positioned itself next to the dead whale and scientists swabbed the carcass in order to test for oil toxins and took tissue samples for DNA. NOAA catalogues mammal DNA to record species information and migration of different animals.
As we watched the whale float next to the ship, a 12 foot Tiger shark approached. It was obvious that sharks had been feasting on the whale because we could see definite bite marks along the side.
The Tiger Shark (Galeocerdo cuvier) is a fierce predator that has tiger-like markings and can grow to be over 14 feet (4.2 meters) long. It eats just about anything: fish, turtles, crabs, clams, mammals, seabirds, reptiles, other sharks, and just about anything else they can catch. It apparently likes to eat dead whales too! The Tiger Shark is one lean, mean eating machine. Each of its teeth is shaped like those found on a circular saw with a flat and curved hook at the end. A power saw might not even equal this shark’s power since it can cut through turtle shells with a single bite.
The shark circled the whale carcass and suddenly attacked, twisting back and forth in typical shark style. A bit later, the shark came along side the whale, bobbed up and down and took several chomping bites. Everyone was amazed at what we were witnessing!
Personal Log
As I watched the stunning display before me, I felt like I was a National Geographic videographer! I’ve had some interesting experiences in my lifetime, but this has got to be up at the top of the list! The thrashing and bloody water was unbelievable and watching the bobbing motion of the shark eating the side of the whale was like nothing I’ve ever seen – even on TV! And the SMELL! UGH! Ensign Schill fitted us with respirators so we could go out on deck and not gag.
I’ve also seen thousands of flying fish that actually do fly! They are tiny silver fish whose bodies are streamlined in a torpedo shape that helps them gather enough underwater speed to break the surface and take to the air. Flying fish are thought to have evolved this ability to escape predators.
“Something to Think About”
If this whale did die because of the oil, will we see more dead fish and mammals? How is the oil affecting birds, fish, and mammals along the coast? What will the long term affect be for the Coast?
“Did You Know?”
The tiger shark is one lean, mean, eating machine. Each of its teeth is shaped like those found on a circular saw, with a flat and curved hook at the end. A power saw might not even equal this shark’s power, since it can cut through turtle shells with a single bite.
