A global sampling project of the oceans of the world began on September 11, 2003. It’s scheduled to last for ten years and cost over one billion dollars. The majority of the funding for this project is coming from the Alfred P. Sloan Foundation and several coastal countries. These countries include the United States, Japan, Russia and England.
This may sound like a lot of money but compared to the annual $55 billion dollar seafood business it only a drop in the bucket. The survey will go from the South Pole to the North Pole and from the shore to the depths of the deepest trenches. It will survey plants and animals from both the largest whales to the smallest plankton.
When biologists want to find out what in a given area and how many of a species there are they seldom are able to count them all. So, they take samples. If they could count them all it would be called a census not a sample. Taking samples is always cheaper and timelier than doing a census.
If the sampling is done properly it follows along the lines of an old joke that goes like this. Two men are placed at one end of a long narrow room. One is a mathematician and the other a statistician. At the other end of the room is a beautiful woman. They are told that they can approach the woman only half the distance every ten seconds. The first one to reach her gets a date. The mathematician says it can’t be done because he would never reach her and he leaves. The statistician smiles and steps forward saying, that what the mathematician said was true, he can get close enough.
Some of the methods used to take samples can go from the usual to the unusual and even into the downright bizarre. In the usual category biologist use baited traps to catch field mice. Once they have the mouse it’s tagged and released. They do this over the area in question and using the ratio of tagged vs. untagged mice that are caught to predict the population. By doing this they didn’t have to kill any mice or count them all.
In the unusual category there’s one that sounds like science fiction crossed with high tech – electrofishing. Electrofishing is a highly effective sampling method that has been used for over a century in fresh, brackish and salt water to attract, herd, stun, capture and kill fish. An electrical field generated by passing an AC or DC current through a wire has a pronounced effect on fish. If a fish is close to the field its muscles cramp to the point where it is unable to swim and it floats to the surface. Farther away from the field fish goes into forced swimming and moves toward the point of the field’s origin. These responses have lead to the development of electric seines, trawls, boats and other gear.
Most of us have heard of “Telephoning”. This form of electric fishing has been around for years. Hand cranked telephones generated an AC current which rang a bell at the operator’s station. You might remember playing with a crank phone as a child and found you received a shock if you held onto the output wires while cranking the handle. It works the same on fish. Telephoning is effective for short distances in freshwater during low water when fish are schooled up in shallow pools.
Electric trawls for shrimping have a current running along the lead line that causes shrimp buried in the mud at night, to jump and be swept into the trawl. The Russians in the 1950’s used 10,000 amp generators with open ocean mid-water trawls to direct schools of fish into the trawls.
A recent development by the British has got to be classified as bizarre. Scientists at Britain’s Royal Society for the Protection of Birds have developed a sampling device for insects called the ‘Splatometer’. While they are primarily concerned with birds their food supply has been thought to be decreasing so they felt the need to find out how many insects were available. A detachable postcard size piece of plastic is place on the windshield or license plate of a car and then they are driven around the area of interest. Every 30 minutes the plastic is removed and a new one set in its place. The insects are then counted out by species and used as a relative index of abundance. Talk about Englishmen and the noonday sun!
Whether we use traps, electricity or something totally different it is all sampling in an effort to get information that’s accurate enough to use for management.
Think Global, Act Local!