Dr. Block’s team has tagged over 850 Pacific bluefin to date and most of these were smaller fish that showed extensive residency in west coast waters. She has since 2015 been very interested to get as many electronic tags in large CA bluefin as possible to try and better understand just how old pacific bluefin are when they return to spawn in Japan and Taiwan waters.
Her tags reveal a trove of scientific information on migration routes, growth, feeding and environmental conditions which can only be accurately studied through the use of the very expensive and specialized tags Dr. Block is using several types of tags inserts, one that is called archival and inserts into live bluefin freshly captured and properly handled by the capture crews. This surgery takes place in less than 2 minutes and the tag is stitched up inside with a long stalk that comes out with sensors. The bluefin carry a green conventional and reward address and $250 is provided to anglers if returned.
A second tag, called a pop-up satellite tag records the same information but detaches from the bluefin at the end of its one-year sojourn on the tuna. When it pops up it providers her team with an exact location to recover the tag and transmits the data. While we were out a tag put on a Monterey bluefin popped off on San Clemente’s east side and her team recovered it. The electronic tags are expensive with the cost rivaling a laptop computer! Some of the tags inserted into bluefin on this trip were funded by CCA CAL Board Members and CCA CAL Life Members.