White Marlin Science

We worked on a research project yesterday… which means we went fishing. We went out to catch white marlin. We are actually helping with two projects being done at Dr. John Graves’ lab at VIMS. White marlin are considered a single stock but with the bite going off at Virginia, Venezuela and other locations at the same time, there may be separate stocks that should be managed  separately. We’re collecting DNA samples here and others are collecting samples elsewhere in the Atlantic so that  the molecular genetics can be compared. The other thing being looked at is the affect of removing the fish from the water has on post-release survivability. The marlin are caught on circle hooks, brought into the boat for various amounts of time and a pop-up satellite tag is placed. The fish is revived and released. Post release mortality will be compared with 60 circle-hook caught white marlin released at boat side in a previous PSAT study.

Our trip actually started Thursday night when we headed out to the Norfolk Canyon in the dark. We got there about 2 AM and trolled in the dark hoping to catch another bigeye tuna. We did not get a tuna bite. At first light, we had the marlin spread out and saw our first marlin soon after. Dr. Graves said that we have a problem. He did not have the special tag stick needed for the PSATs. He said that we’ll just enjoy the day fishing. I told him that we had two of the best engineers around onboard and that it would not be a problem. Charles Southall and Gabe Sava, in short order, had a tagging stick made from a rigging needle, rigging tape and some type of screwdriver thing. We were back in businesses. Now we just needed to hold on to a marlin. We saw plenty and managed to catch 5. We should have caught more but 5 is good. One of them turned out to be a roundscale spearfish. We collected DNA from each of the fish but only placed PSATs in the 4 white marlin. While marlin fishing, we caught a dozen or so dolphin. We’ll be out there doing more research as soon as the wind lays down.