No species on the West Coast has earned the admiration of saltwater anglers quite like the Pacific Bluefin Tuna.  The recent cycle of fish has placed this species in the Southern California Bight in significant numbers with some robust catches being made. With this influx, many are asking if “this is the new standard? Can we expect even larger breeding specimens than what we’ve seen over the past several years?”.  While Pacific Bluefin Tuna are not uncommon in the Southern California Bight, what has been unprecedented is the sheer volume of fish that has set up its home base off our coast. 

Dr. Barbara Block is an American marine biologist and Charles & Elizabeth Prothro Professor of Biology in Marine Sciences at the Stanford University Hopkins Marine Station and a co-director of Stanford University’s Tuna Research and Conservation Center, with the Monterey Bay Aquarium. While her works in the field have expanded a myriad of topics, she is a leading expert when it comes to the study of the Pacific Bluefin Tuna in the Eastern Pacific. She’s a leader in all things Bluefin and is looking to figure out the intricacies of this amazing fish.

Recently, Dr. Block and her team made the pilgrimage to Fisherman’s Landing in Point Loma where they boarded the SHOGUN, for a 4-day tagging trip for Bluefin and Yellowfin tuna.  A daunting task when you consider how fickle catching these gamefish can be, in addition, to safely capturing and tagging, and releasing.

Over the four-day trip, Dr. Block and the team were able to put out 39 electronic tags on 35 fish. 33 archival, 5 satellites, and 1 heart rate tag. Bluefin tuna were primarily tagged and a few yellowfin were mixed in, fish ranging from 20-220 lbs. Additionally, the team was able to collect 8 small bluefin tuna for their facility at Stanford. These fish were carefully captured, held in large bait tanks, and were later delivered via truck to the Monterey Bay Aquarium.

After their trip we were able to connect with Dr. Barbara Block and ask her the question she’s probably been asked a thousand times by Southern California anglers:

“Are there bluefin tuna breeding here and is this their new home?”

The simple answer is, unfortunately, NO, there have been no specimens of breeding size or with mature reproductive organs found in our local waters. This explains why we haven’t seen fish in our fishery over the 400lbs. mark. Once they reach this size they high tail it to the Western Pacific Ocean to the Sea of Taiwan and Japan to begin their breeding cycle. The large influx of fish in our waters is based on a need to feed and forage in our productive waters.


You’re going to like the answer to this question, you can get involved by going fishing. There are substantial numbers of tagged fish that have been released into our water. Returning one of these tags/ tagged fish is a huge necessity as it will give scientists a significant amount of information into behavior, health, forage, water quality, migrations, and more. Take note, tags have been placed on both Yellowfin and Bluefin Tuna locally. If a tag is found, you can contact Dr. Barbara Block at 831-655-6236 or reach out directly to Danny Fuller at the IATTC.


  • EXTERNAL ARCHIVAL TAGS: these are pop-up satellite archival tags – they ride on a bluefin tuna for up to a year.  At the year mark, the tag pops off with an electronic release and then transmits the data back via satellite. These tags were placed on the biggest bluefin captured which are designated for year class 5-8, the objective is to learn if the large fish remain in the Eastern Pacific.
  • INTERNAL ARCHIVAL TAGS: These tags are placed internally in the fish and have a green and white floy tag (2) on the outside.  It’s important for anglers to know that if a specimen is caught with this tag, they can be rewarded $250 reward for the return of the tag.  This tag enables scientists to download the data and plot where the tuna has been. Each tag can record up to 5 years of data.
  • DOUBLE-TAGGED ARCHIVAL AND HEART RATE TAGS: This is a first and has been placed on Yellowfin Tuna. The heart rate-tagged fish have red and white tags, and they are worth $1000 for the return of the entire fish. They were put in small tunas and will be in both species going forward. They will assist in recording information about the capacity of tunas to endure the warming ocean and their cardiac physiology.
An example of how the tagging information is able to monitor a tagged bluefin.

Dr. Barbara Block and her team would like to extend a special thank you to the crew on the SHOGUN for the hard around-the-clock work in making this trip happen.