Do you know what is harder than tagging adult hammerhead sharks? Juveniles!
For one thing, they are picky eaters and have small mouths, the other, they roam around. But this doesn't stop me from going out and trying, after all I have no choice, I have to tag and track!
For this chapter of the southern Queensland Hammerhead shark project, we are tracking the movement and habitat of juvenile hammerheads. Super exciting and as I learned, it's about time on water! Lots of time on water!
At this stage I have tagged two juvenile scalloped hammerheads and have two tracks. They are small. They are born at 30 cm (total length) and unbelievably cute, just have a look:
Energetic little sharks, and for this reason I ask people that catch them as by-catch to please keep them in the water or be as fast as you can! I love these things :).
Because they are small and are very light, we use acoustic tags to follow them, for this part of the project we need high resolution data, so we literally follow them on a boat with expensive gear for 24 hours after tagging, its long but it will allow we to plan the next phase of the project. Invaluable information.
These tags are expensive and last only 30 days which means a lot of time for me. But this is were volunteers come in! Day and night, cold, windy and rainy, we still need that data. Thanks to these guys it's attainable.
These trips took some time but when we caught one, time seemed to just fly by. Maybe due to everyone working? maybe due to excitement? I remember being tired thinking "great, no data again!" and then BAAM! five hours seemed like five minutes..
The problem is repetition. You need as much data as you can get to show your result with confidence. After we tracked this little guy:
we needed to sleep and head out again then next day and find it to obtain another track. So we did, but the shark was no where to be seen, or should I say heard.. I spent 5 days looking for it, over 100 km, inshore and offshore lead to no detections, which is a result, this means either it has moved out of the area or it was eaten by a bigger shark. The areas they inhabit are also home to bull sharks.
Either way, only one more to tag and that will be the end of this chapter, then we will be planning the next stage for this project! Stay tuned we will be needing volunteers!
Johan