The mood is very heavy on board the ship this evening.

The expedition has been going exceptionally well. The scientific team has been having great success locating schools of sharks and diving down to place tracking tags on them. This has buoyed their hopes of capturing a hammerhead and outfitting it with a satellite tracking tag to track its journey around the ocean. But now, those hopes seem to be sinking fast.

From my experience, our anchor spot at Wolf Island is one of the most electrifying dive spots anywhere. Sharks are everywhere. But what these scientists propose to do looks to be extremely difficult. They want to bring a hammerhead on board the boat while keeping it alive to attach the sat tag.

Photo: Thomas Lucas

To practice their technique, the crew sent a team of fishermen out to hook another type of shark... a Galapagos shark... and tow it back to the ship. The idea was to pull the shark onto a sling, then use a crane to lift it onto the deck. Seawater would be pumped across the shark's gills to keep it breathing.

They hooked the shark, but it fought back every step of the way, thrashing and kicking. Finally, after a long and agonizing struggle, they got the shark onto the deck... then installed the tag and let it go.

Given how difficult this was, the risks in capturing a hammerhead now seem a whole lot higher. For one thing, they are "ram ventilators," they must always swim forward to keep water moving over their gills. When they are restricted, as when caught on long lines by fishermen, they easily die.

If a hammerhead were to die, word would likely get out. Hammerheads have become a symbol of conservation and tourism in the Galapagos, which explains why a National Park representative on the boat now is very angry about how long it took to tag the Galapagos shark. The purpose here is to find ways to protect sharks from severe fishing pressures, so killing one, even for science, is just not an option.

For now the team has decided to go ahead with the plan, but the lead scientist, Dr. Peter Klimley, is vowing to shut down the experiment the minute he thinks a hammerhead is in danger. And now something else has come up. The fishermen themselves are saying they are not even sure they can get a hammerhead on the line.

The entire team is now really torn between the desire to complete the experiment... and the fear of losing a shark in the process. It could really go either way.