Friday, August 26, 2011

110 Bluefin Tagged!

Another report from the F/V Shogun...

The tagging effort aboard Shogun continued as TAG team returned to the region of Tuesday's hot bite, less than a 14h run from San Diego. We picked up right where we left off. At dawn after drifting for 3 hours we were just about to pick up and leave to start searching for fish in less than ideal conditions, when our TAG summer intern, James Stiltner hooked up on a bluefin tuna. This morning the team of interns, graduate students, post-docs and techs had set up for tagging and loading fish into the wells. The Shogun crew led by Captains Norm and Bruce, with Randy, Tommy, Scott, Chachi - snapped into action and had bluefin lined up for the swimstep team who were often waste deep in water as the rough conditions made things sporty. Sure enough before 8am we had put out the remaining 7 archival tags –for a grand total of 110 tagged bluefin in two stops! Bluefin of a perfect size and yellowfin were loaded onto the ship at sunrise. The bite was wide open, and it's hard to imagine the quality of fishing we observed. More samples were taken to observe diet and isotopic signature which enables the team led by Dan Madigan to discern where these two year old tunas have come from. All and all it was a wonderful day- despite some challenging seas.

Thursday, August 25, 2011

Tuna Road Trip

A report from the Shogun crew...

Today we unloaded the 26 bluefin and one yellowfin tuna to the truck and pool located at the pier at Scripps Marfac dock. Half the fish were loaded into the “tunabago,” the transport tank that gives the bluefin a free ride up the California highways to the Tuna Research and Conservation Center (TRCC) at Stanford’s Hopkins Marine Station, in Pacific Grove. Thirteen bluefin tuna, all about 15 lbs at most, were loaded into the holding tank on the truck and another group swims currently in the pool at Marfac. Every fish was handled in a sling of water beginning in the wells aboard the Shogun where Alex Norton (our tuna whisperer) gently cradled each fish. They receive an Avid ID tag, get a length measurement and then are sent in the sling through a series of gentle hand lifts or carries that takes the fish to the truck or pool. It’s a well choreographed ballet where the team, tuna, water and strength all combine to move tunas from the ship to the transport truck. We all admired the great color of the bluefin, their stripes all lit up as they entered the cool waters in the truck. They will get the ride of their life to their new home. We were thrilled at the great condition of the fish and after loading with new bait headed back out to the fishing grounds.

Wednesday, August 24, 2011

One for the Record Books

As scientists, anglers and passionate fans of Pacific bluefin tuna we live for day like we have had here on Shogun in the past 24 h. Our mission- to collect tunas for studies back at our home laboratory- the Tuna Research and Conservation Center (TRCC). We arrived in the area where fishing reports had been excellent and proceeded from dawn to dusk to have a wide open bluefin bite. And this time, for the first time in years, we were more than prepared. The Stanford University team had programmed over 100 tags prior to coming out on the trip and anticipation was high.

This year we had some older TAG team members from our lab, including Tag-A-Giant and TRCC technicians Robbie Schallert and Alex Norton, Stanford technician for our Gulf oil spill team Ben Machado. Also on board were Stanford graduate students Dane Klinger and Dan Madigan, and undergraduates who had interned with the TRCC this summer including undergraduates Natalie, Ethan, Sarah, Andrew and James.

Captain and Professor Norm put us in a great spot to drift and before sun up Dan Madigan hooked up. This year to prepare with our younger team, we had held a “tagging class," and went over the cradling of fish on the swim step. Sure enough chaos occurred during the first fast bite when the team barely had their feet wet. We put the fish that first appeared as yellowfin into the side wells and quickly filled to capacity.

We then heard the first call from the crew of,  "Bluefin!"  The tagging team (Barb, Robbie, Dr. Joe Bonaventura) went into the action- tagging 7 yellowfin. The bite slowed down and we moved on. Within an hour, Norm glanced and viewed a sonar hit that was extremely interesting- the fish were down on the thermocline- in the “feed layer” or deep scattering layer the area I call the "peanut butter of the ocean," filled with small crustaceans and squid. From the moment we stopped on the sonar school until 6 PM we had steady bluefin action that led to what I think may be the highest single electronic tagging stop for bluefin tuna-96 archival tagged bluefin (all with one tagging station!). In addition, we filled up the slammer with bluefin. Scientific samples were taken by Dan and Ben from a handful of bluefin to discern isotopic signatures (think "You are what you eat!") and to also determine from where the fish had come (signatures from the open sea are lower in numerical value than in the productive California Current).

I was a bit surprised to see Captain Bruce, Randy and Tommy admiring an albacore as if they had not seen one in a while. This was the first albacore of the season – remarkable given it happened the third week in August. I thought the albacore were quite skinny - suggesting they had come from offshore. History was made here today aboard the Shogun-by the end of the day, we had collected all the bluefin required for the TRCC this year, tagged 103 tunas and released another 50 more. All in all, we could have tagged 200 bluefin today! Too bad we did not have more conventional and electronic tags! The fish were very young, potentially new arriving fish on the west coast. From prior tagging we know that this year class will be retentive to the California current and provide super fishing on a 30lb 3rd year fish next season so let’s hope their survival will lead to more knowledge and great fishing!

-Dr. Barbara Block