With that being said, there is a certain science to performing a survey of the sharks. Here is how it is done. There is much preparation before leaving port to do a survey. NOAA Ship Oregon II cannot leave port without , and lots of it. This is the bait that is used to catch the sharks. The hook of choice is a circle hook. The fishing line is monofilament and extremely strong. These are the basic items needed, but there are numerous other tools needed such as the cradle for larger sharks, tagging tools, vials for samples, and the list goes on. Suffice it to say, once the ship leaves from port, everything has to be on board in order to have a productive survey.
Anyone who fishes knows there are numerous ways to catch a fish. So how do you catch a shark? If you’ve ever seen the movie, “The Perfect Storm,” then you have a good idea. The method used is called longlining. As the name claims, this method makes use of a long line. The line must first be prepared. In order to do this the circle hooks are baited with Atlantic mackerel. There are 100 hooks in total to put on the line. The hooks are part of a unit called a gangion. A gangion consists of a leader, a monofilament line, and a circle hook. These are placed in a barrel. There are 50 gangions with bait per barrel, for a total of 2 barrels per fishing set.
The last thing we learned was how to bait a hook. These hooks are big! Atlantic Mackerel are used for bait. We must be careful to double hook the bait or it will fall off.
After the line is set and the work station is cleaned up (that bait can get a little messy!), a CTD is deployed to gather data on the water – Conductivity (a measure of salinity), Temperature and Depth. The CTD also measures the dissolved oxygen in the water – remember that fish breathe by absorbing oxygen from the water as it runs over their gills.