Thursday, September 18, 2008

Tagging Tuna in the Trench with the 4Gs

Latest New Zealand Tagging Report - Submitted by George Shillinger

Although it was difficult to leave my colleagues and the crew behind on the Cova Rose, it was exciting to board the Cerveza 2 again and to rejoin Captain Larry Johnston, his crew, and the Greymouth Guzzlers (4Gs).

Figure 1: Captain Larry Johnston (left) conducts pre—departure briefing with Mike Trousleau (center) and Dr. Gary Rae (right) in the cockpit of Cerveza 2. (Image: George Shillinger)

The 4Gs were back for their 2008 Cerveza 2 charter and had been eagerly awaiting the rare good weather window for another crack at the giant bluefin. In spite of conflicting reports, the weather cooperated and I joined the 4Gs for one of the smoother Bar crossings in recent memory. The winds had calmed to less than 10 kts and the swell had dropped to under 2m --- classic bluefin fishing conditions for the Trench.

Figure 2: Ocean fog and mist envelope the West Coast of the New Zealand’s South Island --- a northward glimpse from the mouth of the Greymouth River. (Image: George Shillinger)

Thus far, the fish had proven a bit more fickle than those of the past two seasons. During previous years, we experienced a steady twenty-four hour per day bite, due in large part, to the high number of hoki trawlers working the trench around the clock. This year, fewer trawlers and a full moon presented additional challenges. But, in general the “bite” was normal, kicking-off at dusk and waning shortly after dawn – a consistent pattern supported by our own analyses of tuna dive behavior, and familiar to many fishers worldwide.

Figure 3: Deckie Josh baits the line for angler Kevin Beems in preparation for the evening bite (Image: George Shillinger)

Sure enough, our first hook-up occurred at 7:00 p.m., on the cod end of a bursting hoki bag, as darkness cloaked the trench. The monster tuna was brought to the boat within less than an hour but it suddenly awakened at the trace, snapping the leader with a swipe of its jaw, and charging into the depths before we could muster a tag shot. Undaunted, we dashed back to the trawler and tossed another bait.

Figure 4: Deckie Redz prepares to toss a hoki bait behind the trawler Rehua (Image: George Shillinger).

A second fish, green and full of fury, was lost again at the trace before 8:00 p.m. Finally, shortly after midnight, following an epic 2.5 hour battle, angler Ian Boustridge (Beau) brought an estimated 350 kg giant to the rail. Deckies Adrian and Redz masterfully wired the monster tuna for me to make the tag stick, while deckie Josh Worthington extended over the rail, snagged a fin clip, and severed the trace at the eye of the hook. The leviathan fish glared menacingly upwards at us as the leader broke and then kicked away with a series of powerful tail beats.

Figure 5: George Shillinger prepares to deploy a satellite tag on a giant bluefin captured by Angler Ian Boustridge and leadered by deckies Adrian and Redz. (Image: Garry Rae)

The team continued to fish through the night and several hours later, during the pre-dawn, disaster struck as angler Clark Boustridge brought another beautiful fish (~ 260 kg) to the rail. The fish, still green, charged under the boat and was mortally wounded by the propeller. The loss of the fish that we were planning to tag was difficult for all. We collected fin clips and tissue samples for DNA and stable isotope analysis and the 4Gs took the remainder to share among family and friends.

A few hours later, at 8:30 a.m., Garry Rae landed the final giant bluefin of our trip. It was a thrill for all of us to “see the dentist in the chair” again at last!.

Figure 6: Angler Garry Rae in the chair on a dawn bite as deckie Adrian awaits the trace. (Image: George Shillinger)

During the course of a 1.5 hour fight, Garry skillfully brought the fish (~ 200+ kg) to the Cerveza 2, enabling deckies Adrian and Redz to guide the fish into position for an excellent tag shot.

Figure 7: George Shillinger prepares to tag the fish captured by angler Garry Rae with deckies Adrian (center) and Redz (left) working the trace. (Image: Ian Bosutridge)

Figure 8: Deckie Josh Worthington (holding cutter) prepares to cut the trace on angler Rae’s bluefin. (Image: George Shillinger).

Finally, after 48 exciting hours of battling and tagging fish in the Hokitiak Trench, the 4Gs and Captain Larry made the executive decision to return to Greymouth. We were all weary but grateful to have experienced yet another exciting and memorable adventure --- and we are all looking forward to seeing this year’s tag returns and hoping for another trip together during 2009!

Figure 9: Snow capped mountains and seabirds frame the scene during our return from tuna tagging off Greymouth, New Zealand.

No comments: