Shark dissection time! As the day progressed so did the excitement of the volunteers, constant questions of “Can’t wait, when we going to start?” become the order of the day. As we start the setup of all the dissection and measuring equipment, I could see all eyes firmly focused on the defrosted male vaalhaai, or soupfin shark, that was wrapped in black plastic bags.
Before we could start with the actual cutting open of the shark, we needed to do external measurements. This is a lengthy process but as I explained to the volunteers that this is a very important part of the scientific process. The volunteers quickly jumped at the opportunity and listened carefully to the instructions given. I gave one as the volunteers, Jaime, the opportunity to lead with the measuring, since he had a degree in marine biology and this could really help him to gain some hands-on experience. I explained the basics of measurements and guidelines, and then very quickly they started to taking accurate measurements of the shark with my supervision.
Finally when we were done with the 3-page external measurements, it was time to cut open the 17.5kg shark. To add to the atmosphere the perfect sunny spring day turned into ominous cloudy windy weather, it’s almost if Mother Nature knew how to set the scene. As I started making the first cut, I noticed some of the volunteer’s faces pulled in all different directions as the dead shark smell filled their nostrils, especially when squeezing out the stomach contents to weigh. As the chorus of “ewwh’s” and “ahh’s” rained down, the fascination and interest remained as no-one moved an inch.
We opened up the shark, removing the liver, stomach, intestine and reproductive organs, all for internal measurements. The longer the dissection went on the more questions of genuine interest followed, ” How does the shark stay afloat?” was one of the volunteer questions. So sharks do not have a swim bladder like other fish for buoyancy but instead they have a liver filled with oil called squaline. I happily showed them by cutting a piece of liver and throwing it into a bucket of water, and as predicted it floated! It’s these types of practical demonstrations that have the biggest impact and can only be shown to people at an educational dissection.
After the organs from the body cavity were removed, I went on to show them the brain, eyes and heart, at this stage they were amazed how tiny the heart was in comparison to the body, and where it was located, in the upper throat section, “Talking about heart in your throat stuff” was one of the comments that had the group laughing. After all was cut open and measured, we then took some genetic samples and fin clips to finish off the dissection.
The group were all smiling and showed genuine interest throughout the dissection, for some this was first time they had ever been a part of a dissection, let alone a shark dissection! The group left with a newfound respect for these amazing ocean predators, and a comment by one of the volunteers to end of the day saying: ”This was one awesome experience, that I’ll probably never forget”!
Ettiene Roets (IMV Coordinator)