Tom’s Update October 2025: Highlighting Ongoing PIER Research

Tag Recapture!

One of the swordfish that PIER tagged was recently recaptured by one of our local swordfish fishermen, Kent Jacobs on the Patricia J.

The best thing about a tag recapture is the data! When PIER gets a tag return, we are able to download the full archived dataset, which tells us the exact depth and temperature of the fish over the entire track period.  These data are extremely useful for designing fishing gear, increasing gear selectivity and understanding how swordfish use the waters off Southern California.  About 15% of the tags that PIER deploys on swordfish are recaptured.

From the most recent tag we observed that the swordfish spent considerable time at the surface basking this summer.  This is not a rare behaviour, but the amount of time spent at the surface was considerably more than what we typically see off Southern California.

By the end of the track (at the beginning of September) we started to see what we typically consider to be “normal” for our waters, with the fish spending significant time at depth during the day.  From the record it looks like early 2025 was a good time to be hunting with a harpoon and that September is when local fishermen might start thinking about fishing with buoy gear.

While measuring gear and getting ready for the swordfish season, the team caught, tagged and released this very large bigeye thresher shark just outside of Oceanside Harbor.  The shark was a male and in great shape for the release.  We estimate the shark to be between 4 and 5 hundred pounds.  Bigeye thresher sharks are one of the few species we encounter when using deep-set gear while targeting swordfish.  Fortunately, our data show that they are quite resilient and typically survive the capture event.

Looking Forward:  Although this is our busiest time of the year, the team is excited and anxious for the fall, as it typically brings good fishing and the time to start thinking about the field.