The Billfish Research Project team constantly asks questions and probes the boundaries of scientific information. One of these areas of interest is research into the blood physiology of sailfish. In an ideal hypothesis testing we could analyze the blood physiology of a sailfish before it was caught. Being able to do so would allow our research team to compare the physiology before the hookup, during the catching and then while at boat side. Unfortunately this is just not possible. We can only examine blood physiology from samples taken at boat side. While the procedures for extracting blood from a sailfish are pretty much the same as most larger fish it is still a task which must be well planned and executed prior to attempting.
Being able to examine the blood physiology will give insight into the stress incurred by the sailfish by examining the pH level. Without the pre-catch data a comparison can not be made; however, it is possible then to deploy a PSAT into the fish, measure the level of dissolved oxygen at the release site and then examine the data recorded by the PSAT to gain information into what temperature and dissolved oxygen levels were preferred by each fish examined.
The team is currently working on this idea and welcomes input into the design of this project.
Sailfish color change indicates stress
In the lefthand photo the bright colors of this just hooked sailfish are readily apparent. This coloration is typical of a sailfish that is not stressed to the point of heavy exertion. These colors are what the angler usually sees when a sailfish comes into the teaser spread behind the boat and eats a bait. The brilliant colors are remarkable to see and represent one of the most exciting moments in sportfishing. Anglers frequently refer to the fish as being "lit up!"
However in the righthand image it is clear that this sailfish has some level of stress as a result of the catching process. This is indicated by its dark appearance. Chromatophores produce this color change as a result of the stress. The team believes that this is a response to elevated blood PH levels. Most sailfish caught by the sportfishing community exhibit this color when brought to the boat for release. If the fishing crew takes sufficient time to slowly move the boat forward while water flows over the gills, the sailfish will revive and begin to display the beautiful chrome colors as its stress level, and presumably its pH level, starts to subside.