Tuesday, September 30, 2008

An angler’s perspective on trench warfare

George Shillinger provides an angler’s perspective on tuna tagging research.

I thought that it might be exciting for our readers to provide an angler’s perspective on the fishing and tag deployment experience off Greymouth, New Zealand. I received the following email from angler, Tom Thomson, who is featured within my birthday bluefin blog in this series, regarding our trip on Aug 27-28, 2008.

Christchurch, New Zealand Angler Tom Thomson reports to George Shillinger about his experiences on the Cerveza 2:

Monday, September 22, 2008

Hi George,

Great to hear from you….

We all arrived back very tired on the Thursday night and I found it really tough trying to keep my eyes open for the 3 hour trip back to Christchurch whilst the other drifted in and out of sleep. We had probably one of the most memorable fishing trips we will ever experience and they are still raving about it.

We had some of the fish in a raw state but most of it has been smoked and vacuum packed and it is amazing how many friends you have at times like this. The general impression is that is the best smoked fish we have ever had.

The guys who I brought with me were Craig Tapling, Murray Knight, and Steve Muldoon. In the photo below, Murray is on my left, Craig is beside me and Steve is crouched down beside the fish.

Figure 1: Anglers Murray Knight (left), Tom Thomson (center), Craig Tapling (right), and Steve Muldoon (kneeling) crouch alongside their giant bluefin. (Image: Deckie Redz)

We fished in the order, Craig (broke off after 10 mins when the reel parted company with the rod under the pressure), Murray (about 2.5hrs), Steve (about 2 hrs) and then me(3.25hrs). Murray's was probably the biggest I think and broke off, like Steve's at the leader while trying to get tags in place. We believe that most of them were around the 250kg mark which is fairly average for the area.

Figure 2: A bluefin about to be released from the trace. (Image: Tom Thomson)

Their fight times were around the 2 hour mark but fish were coming in green and full of fight and causing an immense amount of pain to the deckies. I decided to try and tire my fish out a bit more so that we had a better chance of tagging and releasing him, hence the 3.25 fight time.

I've nicknamed mine 'GT' because he was ultra high performance and is derived from our initials (George and Tom). I've assumed that GT survived the next few days as you mentioned the tag would release if he didn't move for 3 days so I guess we now wait for your next birthday and hope the tag pops up and down loads the information as expected.

Figure 3: Heading for home on the Cerveza 2 (Image: Tom Thomson).

Our group is loosely associated through our jobs and this trip was the culmination of a year's planning. We have all been game fishing before but agreed that this is unlike anything we have seen or experienced and is a once in a lifetime adventure for most of us. Craig and Steve came down from Auckland and Murray and I are from Christchurch.

What other information would you like?

I'm interested in any information you may have on GT and his(her?) exploits.

Kind regards


Tuesday, September 23, 2008

Third Week Tagging Giant Pacific Bluefin in New Zealand

Latest news from the New Zealand tagging team. Entry submitted by Tim Sippel.

After two intensive weeks of fishing, the 2008 bluefin tuna satellite tagging program had made good strides towards the goal of deploying 25 pop-up satellite tags. Although New Zealand’s winter weather hasn’t been great this season, we’ve managed to tag 21 bluefin by the end of August.

The first week of September brought a spate of unpredictable weather, making it difficult for several days to figure out when to go out again. On September 4 the call was made to go out for another charter with Captain Chinner, and crew Josh, Bryce and Andrew aboard Cerveza II. The west coat of New Zealand is dotted with numerous fishing ports that require crossing over submerged sandbars. Greymouth is one these ports, and its bar can be troublesome for even the most seasoned and confident skippers. On this trip, Chinner’s unrivalled experience and iron clad confidence navigated us through a gauntlet of white capped waves that would have chased many other skippers back to the docks.

Figure 1. Cerveza II leaving for a bluefin trip from Greymouth’s harbour greeted by ocean waves across the local sandbar. Photo: Pete Idoine

With those obstacles behind us we motored for the hoki trawlers, about 35 miles offshore. However, the unpredictable weather was worsening, and not improving as forecasted. By nightfall winds were up to 35-40 knots and conditions weren’t fishable, so we hunkered down and stopped fishing for several hours to let conditions ease down again. When things settled back down we moved back to the hoki trawlers and put lines in the water. After a few hours we hooked up, and the fishers who chartered the boat got the one they wanted for ‘kai’ (Maori term for food) to share with family and friends upon returning to port. One +200kg plus bluefin provides a lot of kai for a lot of people, so the next was to be satellite tagged. In the early morning of 5 September we hooked up to a bluefin to be satellite tagged. With a chop still on the water, deckies Josh and Bryce got the fish to the stern. However, the leader clipped the boats trim tabs in the process, and was frayed and weakened as a result. Within mere seconds of tagging this fish, the weakened leader broke and with a swift kick the bluefin disappeared. After being battered for much of the last day on the water, it was particularly disappointing to loose this fish, but that is the nature of this work.

After putting in a few more hours of unsuccessfully trying to hook another, it was time to head back. As we headed in the weather finally eased back and the trip back was swift in the calmed seas. Thankfully, the charter Oracle was headed out for a new charter at the same time we were returning. Oracle’s skipper Mike Boswell generously agreed to let me ‘tag along’ on his trip too.

Oracle takes a different approach to bluefin fishing by using only stand-up gear instead of the more commonly used fight chair in New Zealand’s big game fisheries. Oracle arrived at the hoki trawler ‘Rehu’ in early evening and lucky angler Peter Idoine was the first to hook up soon after his line was wetted. Pete had never been big game fishing before (although had caught some yellow tailed kingfish previously). Learning to gamefish for the first time by using stand up gear on giant bluefin is akin to introducing someone to the rodeo by strapping him straight into the saddle with a bronco. Pete proved to be a natural and showed great poise in bringing his fish to the boat in just over 2 hours though.

Figure 2. Pete Idoine battling his first bluefin, with Tim holding onto the back of his belt for good measure, and deckie Aaron looking on in the background. Photo: Pete Idoine

With Pete’s fish landed it was time to chase another for tagging. As the clock stroked 11pm on the night of 5 September, line began screaming off of the reel again as we’d hooked another bluefin. We had no clue what was in store for us with this fish though. When using stand up gear on bluefin, it is not uncommon for the fish to outlast more than one angler, requiring the rod to be passed to fresh legged fishers. However, it is less common for one fish to outlast 8 anglers and wreck at least 4 different gimble belts over a 12 hour period! It was as if the beast hooked on the end of this line was Michael Phelps embodied as a tuna if you considered each of the 8 anglers he beat a gold medal in the gamefishing Olympics!

Anglers Peter, Grant, Peter, Yab, George, and Tom lined up to take turns battling this fish. When passing the rod from one angler to another, it took all hands on deck to unseat the bent rod from one anglers gimble belt and reset back into the next angler's gimble belt.

Figure 3. Four people struggling to unseat the rod from the anglers gimble belt so it can be passed onto the waiting angler behind while the bluefin continues his unrelenting battle. Photo: Pete Idoine

Around 5am I went for a nap as there were no signs of this fish surfacing soon. I awoke around 7am to fresh sunshine and angler number 5 online with this same fish and no indication that it was anywhere near as tired as the 4 other guys who had taken turns online with it. Eventually angler 5 relented to angler number six who eventually relented to anglers seven and eight, who were actually two guys who’d already been online with it in the previous night. Finally as the clock passed 11am this bluefin surfaced and George (man number eight) dug deep down to get it to the stern. And then as suddenly as this fish was initially hooked, it just as suddenly flicked it tail, catching the line on the boat’s hand rail and snapped the line. After more than 12 hours this bluefin was gone in less than a second!!! An exhausted disbelief fell upon everyone aboard, and the decision was made for everyone to get some sleep. Everyone was spent, and we needed to recoup for a second night of fishing.

We awoke in the late afternoon and chugged back to the hoki trawlers for another go at luring a bluefin online with a yummy piece of defrosted hoki. Although I was on the boat to tag fish and was not anticipating catching one, the anglers wryly told me I’d have to share the pain in catching the next fish if I could have a chance to tag it. I agreed as I was there to tag and was the only non-crew member there who hadn’t been online with the 12 hour beast. After dark we hooked up our 3rd fish which was initially fought by two anglers who were still weary from the 12 hour battle. Angler 3 was me, so the gang converged to help pass the rod over. The heat was on both literally and figuratively as I could feel my thighs burning and I had been at sea for roughly 50 hours without tagging a bluefin yet. Thankfully, this fish capitulated to the stern in 45 minutes, but to my dismay the decision was made to keep it instead of tag it. Nevertheless, I am grateful to the anglers for allowing me to join them on the trip they had chartered. It was a privilege to experience a giant bluefin on stand up gear. Everyone, including the anglers as well as captain and crew of the Oracle are first rate!

Figure 4. Tim hooked up with Tom anchoring the back of the gimble belt. Photo: Pete Idoine

Oracle’s mission was complete, but yet again as one charter completed, another was about to begin. Chinner happily agreed to take me along on his next charter again, so I immediately joined them for another try to tag bluefin with one of the four tags remaining to be deployed.

Reuniting with Cerveza II was welcome under the settled and more favourable weather than the last trip. The charter on Cerveza this time was a group of farmers from outside of Christchurch who’d come to experience bluefin fishing and likewise bring a bit of kai home. I explained what the project was about, showed them some satellite tags, and explained the value of this research. Once they’d landed a fish to bring home, they were happy to allow any others to be tagged for this research. Cerveza II and numerous other boats in this fishery have a policy of no more than one bluefin landed per charter to ensure they are also contributing to the equally rewarding pursuit of tag-and-release fishing. By the early morning of 7 September we hooked up to another bluefin. After a relatively short 30 minute time this bluefin was calmly lead to the stern by wiremen Josh and Andrew and after more than 65 hours at sea this time out, the 22nd bluefin of the project was satellite tagged. At an estimated 250kg, it was quickly tagged and upon release it swam away with a calm flick of its tail. At 4:50am, a few hours after releasing that fish another was hooked. It was a livelier bluefin than the last and it was online for 50 minutes before Josh and Andrew brought it to the stern. They positioned it perfectly for a solid tag shot. And with that, this bluefin estimated to be 220kg became the 23rd bluefin satellite tagged in the 2008 project.

As often happened in 2008, the bite turned off at dawn and within a few hours Cerveza II turned for home. This leg of the project was quite eventful and challenging. But with 23 bluefin tagged, the bluefin team at Stanford, Blue Water Marine Research and Auckland University are quite happy with the achievements of 2008. Two satellite tags remain with Chinner who might have an opportunity to tag this week on his final charter of the season. Chinner has seen and done it all before and we’ll be grateful if he can put these last two out. But if not…well we wait with ‘baited’ breath for the data from these other 23.

We also heard from the crew of one of the commercial hoki trawlers that they could see several satellite tagged and conventionally tagged bluefin swimming under their boat, feeding on hoki scraps as the nets were hauled aboard. Great news to give us another shot of confidence that things are going well!

Monday, September 22, 2008

Birthday Bluefin – August 27, 2008

George Shillinger reports from New Zealand on a birthday outing with the Cerveza 2

Following four back-to back runs on three different vessels, I was craving some rest but anxious to finish the tagging work with our team in Greymouth. I had already extended my trip and could not afford to stay any longer.

Figure 1: The docks at Greymouth (Image: George Shillinger)

I was slated to present at the Biologging 3 Conference in Pacific Grove, CA on September 2, 2008 and had to return the US to prepare my talk.

Figure 2: Biologging 3 Conference Logo (Logo by Kate Spencer)

With good weather still on the horizon, Captain Larry announced that we would be making another quick turnaround in Greymouth. Unfortunately, time was too tight for a dinner reunion with the 4Gs. We had plans to depart the following morning with a group of anglers from Auckland who were eager to assist with the tagging effort. I hurried back to the hotel to organize my gear for tomorrow’s deployment.

Figure 3: Revington’s Hotel – our home base in Greymouth (Image: George Shillinger).

Figure 4: Tim Sippel (left) and George Shillinger (right) work in the “office” at Revington’s Hotel (Image: John Holdsworth).

Figure 5: The Jade Café in downtown Greymouth – a breakfast venue for the tagging team when we are not on the water (Image: George Shillinger).

Fortunately, I was able to make a quick morning visit to the dental office of Dr. Garry Rae. It was my birthday in New Zealand (August 27), and Dr. Rae had kindly promised to repair a crown that I lost while chewing candy on my first Cerveza 2 charter (see blog #1) of the tagging season. Thank you, Garry, for the excellent birthday gift!

Figure 6: George and Dr. Garry Rae at Dr. Rae’s dental practice in Greymouth.

Larry arrived at the docks with positive news from several boats about recent catches of large tuna in the Trench. Although weather reports advised otherwise, the winds had resumed and the weather appeared to be taking a turn for the worse as we headed out over the Bar.

Figure 7: View from the boat while crossing the bar (Image: George Shillinger).

The skies darkened and the winds increased to 20-25 kts as we raced towards the grounds. The sea had turned into a rollicking mass of whitecaps and spray, making for an exceptionally bumpy ride. A few of the passengers hunkered down to absorb the buffeting, laying prone on the cabin floor, while the crew focused on prepping tackle and bait, peeling spuds, and keeping cooking gear from launching across the cabin.

Figure 8: Vessels Cascade (left foreground) and Cova Rose (right foreground) wait with Cerveza 2 for the Vessel Rehua (left background) to pull its hoki bag (Image: George Shillinger).

The first trawler that we encountered upon arriving at the fishing grounds was the NZ trawler, Rehua. Sportfishing vessels, Cova Rova and Cascade joined us, rolling in the swells while we waited for Rehua to pull the bag.

Figure 9: Vessel Cascade in the trough (Image: George Shillinger)

With the bag ascending, Captain Larry positioned the Cerveza alongside the trawler, while Deckies Redz and Josh prepped a hoki bait. Angler Tom Thomson, anxiously manned the chair as the Auckland anglers prepared for battle.

Figure 10: Seals and birds feast on scraps from the hoki bag. (Image: George Shillinger)

Over the course of the next 15 hours, we battled strong winds (20-25 kts), a rising swell (to 3m), and three giant tuna. The bite never slackened, but sadly all three fish were lost (2 broke off at the trace and another when the line snapped) before any tags could be deployed.

We finally deployed our first tag of the trip when angler Tom Thomson succeeded in bringing an estimated 225 kg fish to the boat, after a 3+ hour battle that began in the pre-dawn at 3:55 a.m. Although we captured fleeting glimpses of the trace on several occasions throughout Tom’s fight, the fish repeatedly turned tail at the rail, disappearing into the darkness every time capture appeared imminent. Deckie Redz wired the fish and made good on his promise to present me with a “Birthday Bluefin.”

Figure 11: Sportfishing vessels gather around the NZ Vessel Amaltal Enterprise as she pulls in a loaded bag of hoki. (Image: George Shillinger)

Figure 12: After three lost fish and one tag deployed, Tom Thomson (left), George Shillinger (center) and Tom’s team of anglers take a bluefin home for dinner. (Image: Deckie Redz).

With the first tag of the trip finally deployed, the anglers collectively decided that it was time to take a fish. Three hours later we were on our way home with an estimated 230kg tuna headed for the icebox. Meanwhile, I took advantage of the opportunity to investigate the tuna’s gut contents (filled with hoki bones – no surprise!) and collect tissue and DNA samples.

Figure 13: Hoki bones in the stomach of a giant Pacific (Nothern) bluefin (Image: George Shillinger).

As we headed back towards Greymouth, the crew surprised me with a ice cream birthday cake --- apparently a Kiwi speciality (for kids) --- that generated congratulations and fond memories from all aboard!

Figure 14: Kiwi Style birthday – an ice cream cake from the crew of Cerveza 2 for George Shillinger! (Image: Josh Worthington)

Friday, September 19, 2008

Tagging with the trawlers in the Trench

Pete Saul reports on his back-to-back trip on Cova Rose chasing giant Pacific bluefin tuna off the west coast of New Zealand.

It was a quick turn-around with only a few hours ashore. The charter was three enthusiastic south Australians who wanted to land a fish only if it was a potential world record.

Figure 1: The Cova Rose preparing to depart from the Greymouth docks. (Image: George Shillinger)

With the crew all tired from an exhausting 48 trip in which the weather was testing at times and the fishing hard, it was fortunate that one of the deckies, Grant, was returning to Nelson, and Bryce from the first trip was rejoining the boat. He was able to navigate back out to the grounds while Tony, Norm and myself caught up on some rest.

The forecast lived up to its promise, with the sea calming down beautifully by the time we had found our first trawler, the NZ vessel Rehua, north of the Hokitika Trench. At ten past midnight, on just the second pass, we hooked up with Gavin Solly in the chair. This turned out to be an epic battle of five hours and we did not tag the fish which was brought on board. Gavin was astounded at the power of these fish in his first encounter. Even though we had the trace up after just twenty minutes, the fish simply would not give in. We fished near the Rehua until after dawn with only one further strike which did not hook up.

Figure 2: The Cova Rose as seen from the Cerveza 2; fishing off the bag of the NZ Vessel Rehua. (Image: George Shillinger)

Skipper Tony decided to move away and have a look at one of two Korean joint-venture vessels not far away. We have had absolutely no luck near these boats in the past, but this time the move turned out to be a master stroke. The boat had very promising marks on the sounder alongside it, and the fish proved willing to bite. We soon had our second angler, Troy Nissen, hooked up, and he succeeded in bringing his 260 kg giant to the boat in 90 minutes. A bait cast into the sea immediately after tagging Troy's fish was instantly seized by another tuna. The school had deserted the trawler to stay with their stricken mate, and we made the most of our good fortune. Our third angler, Ray Doody, a three year veteran of the fishery, brought his 230kg fish to the boat in 135 minutes as we drifted and chummed on the spot where Troy's fish was hooked. By late afternoon we had experienced several bites that had escaped the hook, but shortly afterwards hooked a tuna that was brought in by Troy in just 30 minutes.

The anglers were getting the hang of this quite rapidly. We hooked up again just 8 minutes after tagging Troy’s second tuna, with Ray again in the hot seat. This fish, another estimated at 220kg, was tagged in just 27 minutes. In an effort to speed things up we tried handlining some tuna, but after several misadventures the fish went off the bite.

Tony moved to another New Zealand Trawler, the Amaltal Enterprise, which was doing its last tow of a six week trip. We followed the trawler for a couple of hours while the anglers had a bit of a rest. Just before dawn the skipper radioed us to say that he was about to haul his net. The cooperation of the commercial vessels has been absolutely outstanding, with Tony’s long experience in the commercial fishery helping enormously as he knows all the skippers personally. At 0530 Gavin hooked a tuna which proved to be the last of this trip. At an estimated 280kg it was the biggest we encountered this time, but was brought alongside in just 25 minutes. A tough struggle on the trace ensued with the extremely green fish fighting all the way up. It took all three crew to bring the tuna within range of the tag pole for a good shot. Unfortunately while trying to maneuver the fish to the stern for a DNA sample it smashed the trace and headed for the depths at great speed.

Although scheduled to stay out for 48 hours, we headed home into a north-east wind and rain. The bait was all but gone, and the anglers all but exhausted after yet another successful West Coast adventure. After two successive trips, I was also due for a rest. For me it was time to head for home. With four tags left to deploy, Tim will replace me for some more trips with Captain “Chinner” and crew.

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.

Thursday, September 11, 2008

Second Week Tagging Giant Pacific Bluefin in New Zealand

Latest news from the New Zealand Pacific bluefin tagging team.

Submitted by John Holdsworth, Pete Saul, Tim Sippel, and George Shillinger

Hopes were high for a successful conclusion of the pop-up satellite tagging in the second week. To maximize our tag deployment efforts, George Shillinger (see his blogs #3 and 5) transferred to the Cerveza 2, leaving Pete, Tim, and John to continue with working with the Cova Rose. As both teams prepared to depart, the weather had cleared again allowing the boats to leave the port of Greymouth on schedule.

The depth sounder showed that the fish were around but tended to stay down during the relatively calm first day of this second trip on the Cova Rose. The fish appeared to be hovering beside the hoki trawlers at 30 to 40 m, too deep for our baits until the feeding frenzy started as the trawl net surfaced (usually once every 3 or 4 hours).

Figure 1. Bluefin marks at 30-40 meters depth.

The hoki fishery attracts all sorts of attention from hungry marine animals. From above, tens of thousands of seabirds, from dainty petrels to huge wandering albatross, competed for scraps and whole hoki. From below New Zealand fur seals dart in and out of the chaotic scene, competing for easy hoki meals with our primary target, giant bluefin.

Figure 2. Tens of thousands of seabirds compete for scraps as the trawlers haul their nets.

A bait thrown into the mêlée at the right time could result in a hook up in seconds. If the tuna were too slow it wasn’t long before diving birds or an agile seal would have our bait at the surface and the opportunity could be missed.

Figure 3. Deckie Norm tosses a hoki bait as the trawler “Rehua” approaches while pulling its nets.

The crew on Cova Rose also had a number of tuna strikes the first day which did not result in hookups. Professor John Montgomery from the University of Auckland was in the chair for the first solid hookup. The 130 lb rod bowed and line peeled from the reel in the giant’s first run. Suddenly the weight seemed to double and the 130 lb nylon top-shot parted and the fish was gone. Possibly another large tuna had swum through the line.

This is a 24 hour a day fishery. In fact catches can be better at night and early morning. An angler must be in the chair and ready all the time our bait was in the water. Volunteers Graham McGregor (Ministry of Fisheries), John Montgomery and Arthur Cozens (University of Auckland) spent long hours on a cold and windy aft deck waiting for that hook-up.

It wasn’t until just after midnight in the waning hours of the charter that researcher and angler Tim Sippel (Auckland University and Blue Water Marine Research) brought a fish in range of the tag pole. Determination to bring a fish to the boat for tagging meant this solid 200 kg fish was online for just 32 minutes, and proved a little uncooperative at the boat. With the tag in place, wireman Norm was leading the fish toward the fish door to get a valuable fin clip for DNA analysis when it turned and snapped the 500 lb trace close to the hook.

Skipper Tony Roach “Chinner” put us back into the thick of more hungry bluefin and it wasn’t long before we had another solid hookup. John Holdsworth (Blue Water Marine Research) was the angler this time. There are not many heavy tackle fisheries left around the globe, but this is certainly one of them. It took a while to get used to the weight of the fish with the reel on sunset (40 kg over the rod tip) for almost the entire time. This fish, estimated 270 kg, took 47 minutes to get to the boat, tag and release. It departed with a couple of tail flicks and a shower of spray. Just two giant bluefin were tagged that trip, and both came in the early hours of 28 August, not long before we returned to Greymouth.

Figure 4. John Holdsworth hooks up just before dawn to catch the second and final fish tagged of the charter.

Meanwhile, George Shillinger and the team on board Cerveza 2 were also finding the fishing challenging. He describes his ensuing adventures in Blogs # 3 and # 5, while Pete Saul and Tim Sippel respectively describe their subsequent trips onboard the Cova Rose and Cerveza 2 in Blogs #4 and #6.

Wednesday, September 3, 2008

TGF Co-Hosts International Biologging Conference

If it swims, flies, walks or climbs, researchers are likely presenting data on its habits and haunts this week at the Third International Biologging Science Symposium. The Tag-A-Giant Foundation and the Tagging of Pacific Predators program are co-hosting the 200+ person meeting at the Asilomar Conference Grounds in Pacific Grove, California.

“Biologging” is the use of electronic sensors, implanted or attached to animals, to track and record their movements, behaviors, physical setting and physiological state in the wild - exactly what TGF does in its electronic tagging research.

Over 130 pioneering researchers from 20 different nations are presenting the most recent findings in this rapidly developing discipline. Symposium sessions focus on advancement of biologging technology, animal behavior, monitoring physiology, climate change, habitat preferences and utilization, and new multi-species observatory networks that take a snapshot of the entire ecosystem. There will also be a special session focused on how biologing data is being applied to conservation and management of wildlife and ecosystems to protect the ocean’s most endangered inhabitants.

The bulk of the presentations will focus on marine life – ranging from whales to penguins to sea otters to swordfish, but studies on a few land animals such as cougars and koalas will be included. Presentations on bluefin tuna include research on all three species - Atlantic, Pacific, and Southern. Several studies partially funded by TGF will be presented: a habitat utilization model for Atlantic bluefin tuna on their Gulf of Mexico spawning grounds, using genetic techniques to differentiate between western and eastern Atlantic bluefin tuna, incorporating tagging data to improve Atlantic bluefin tuna stock assessment models, and habitat preferences of migrating Pacific bluefin tuna.

Other biologging studies that will be highlighted research whether sonar plays a role in mass beachings of beaked whales, or whether captive-bred sea turtles and farmed fish are able to survive in the ocean to the same degree as their counterparts raised in the wild. Another study utilizes tiny accelerometers attached to the jaws of predators to calculate their food intake by measuring the opening and closing of their jaws. Still another uses a 3D version of an accelerometer to record postures and movements of nurse shark courtship and mating.

To read more about the Symposium, including the program and presentation abstracts, please visit http://biologging.wordpress.com/.