This is the final blog post from a shark tagging expeidition that happened in fall, 2009.  Thanks again to Paul Rogers of Flinders University, South Australia and the NOAA/NMFS team for taking the time to provide us with such nice writing and great photos.  Sorry I fell behind on getting all the entries posted!  Enjoy!

Big hammerhead out from San Diego on the last set

On the last set of the last survey, some of the researchers noticed that three of the large surface floats that support the longline were being towed sideways by a large shark. This occurred not long after the gear was set and due to the potential of a large shark becoming entangled in the mainline, we decided to drive the boat over to the line to inspect what had taken one of the baits. As we slowly hauled up the section of line we realized we had hooked a very

large hammerhead. We slowly maneuvered the big hammerhead into the sling and lifted it onto the deck. This was the first hammerhead that had been captured during the modern history of the survey and it was an exciting capture. The species identification books came out as it was not entirely clear< if it was a scalloped or a smooth hammerhead, but following a consultation of the various ‘shark ID bibles’, we believe it was a smooth hammerhead (Sphyrna zygaena). There is little written about this species in the scientific literature and everyone was very excited about deploying a pop-up satellite tag on it to learn about it’s movement patterns, preferred depths and water temperatures.

Why is it important to learn about critical habitats for sharks? – The lost basking sharks of the North-east Pacific Ocean?

Many conversations covering sometimes colorful topics fill the hours on these surveys as the scientists waited out the longline sets. One dinner-time conversation was about the radical extirpations of gigantic and now endangered basking sharks that used to aggregate in some productive areas of the northeast Pacific Ocean. These areas were likely to represent critical feeding and or breeding areas for the basking shark population and they fed in areas where salmon also aggregated. At the time these animals occasionally interacted with the salmon fishery, became entangled in nets, and given their sheer size, it took considerable time to untangle them. Authorities at the time were under public pressure to remove these giant animals from fishing areas and they took it upon themselves to attach large ‘battering ram style’ knife blades to the bows of vessels and proceeded to ram the passive giants to death as they basked on the surface. Over time, fewer and fewer basking sharks were observed and the ‘problem’ went away.

Now, in the era of ecosystem based fishery management, whale watching and whale shark eco-tourism, it is hard to fathom that this practice even occurred this century. The low numbers of basking sharks being sighted have now led to great concern for their population status and they are now protected in some regions. Many scientist and fishers work in continental shelf waters for decades and never see a basking shark. Unfortunately, it is also without doubt that the majority of the current generation of children will not see a basking shark. Fortunately, fisheries culture and societal attitudes have evolved regarding the humane treatment of large marine fauna and the overwhelming ecological and economic need is now to coexist with our ocean giants. Fishers, scientists and fishery managers now broadly agree on the importance of having healthy, balanced ecosystems, rather than just seemingly healthy single-species fisheries, as the two clearly go hand in hand.

-Paul Rogers, Flinders University of South Australia