I was recently invited to a Blue Shark diving day in the UK. I am being a bit vague about where because my article really is a generic one and not aimed at anyone specifically.
The day started with laying out a trail of chum as we drifted. In this ‘scent trail’ the skipper set a line and baited hook for catching a shark with the intent of bringing it on board, showing the guests, taking measurements for research statistics and then letting it go.
Over the years as a TV wildlife filmmaker I have come across many such trips of which some are good and others really bad. Sometimes the quest for good research and care for the animals is diminished behind the need to make each trip pay financially by entertaining guests with a ‘shark experience’.
It was not long before the first shark was hooked and being played alongside the boat. A few of the guest divers were quickly in the water in the hope of seeing the shark swim past. Having tried to dive deep to safety, the shark, now nearing total exhaustion fights with the last of its energy, twisting and thrashing against the line holding it. For me this is a very sad sight and I know at least two of the divers left the water close to tears. At the same time, others thought this was great excitement.
Getting wrapped in the line during this period can be harmful to the shark as well as increasing the time for lactic acid to build up in the muscle tissue which is one of the contributors to the inability of the shark to recover when released. Ideally the shark should be brought in as quickly as possible and so released the same.
It was hauled by the hook and line over the side of the boat where a hose pipe was immediately pushed into its mouth to give a flow of water through its gills in order to help keep the shark alive while measurements were taken and people held the shark in their arms for a photo.
The internal skeleton of a shark is made of cartilage and connective tissue making the shark very flexible and light. The shark has no rib cage, so when it is on land its own weight can literally crush its internal organs. Hence the longer it is on the deck the more damage is done. Also when pulling a shark up and over the side of the boat, the internal organs are pulled by gravity to the lower end of the body. Generally it is far better not to bring any shark on board that is over a meter in length. Any science such as measuring and tagging should be done in the water when ever possible.
If it is necessary to bring a shark aboard then the technique recommended by many marine biologists is to use a sling at the side of the boat bringing the fish alongside and into it. Then lift it horizontally and gently onto the deck. I have done this myself and found it to be very workable and this method decreases the stress and strain on the shark. This sling can then be used to lower the shark back into the water.
At this stage there should be no reason to keep it out of the water for more that a few minutes. I have talked to shark biologists about the practice of putting the hose in its mouth and continually flushing the gills. The over-riding opinion is that this is not a good idea, or necessary, as it is likely to damage the gill tissues and so severely reduce the shark’s ability to recover. However, others are convinced that this hose pipe action does work and is necessary.
Finally the shark was released and lowered back into the water where it finned slowly while sinking out of sight into the depths. Did it live or die? We don’t know. The general consensus from the majority of marine biologists is that the rate of survival is good when care is taken to keep the shark free from over stress and physical damage.
We will forever debate the pros and cons of various opinions on how best to carry out our shark research, while at the same time, caring for the welfare of the individual animals. But in the end, it is the sharks who are paying the terrible price of pain and annihilation. To me we are simply recording statistics of the shark’s demise.
I sat on the boat after the shark was released and found myself gazing at all the incredible technology that lay in front of me. Diving equipment that allows us to explore the underwater world, computers that keep us safe from decompression, clever materials that keep us warm and dry. In the wheelhouse, the navigation equipment, the radar, the depth profilers, the coffee machine. Yet, with all this, we still find the need to put a hook into a shark’s mouth, drag it from the sea and possibly kill it all in the name of science and research. In many ways the human race has come a long way forward from the days of kill or be killed, but at the same time we seem to have kept one foot firmly in our primitive past.
So what do you think? Is it worth stressing out this magnificent creatures in this way to gain scientific research, or is the risk to their health just too high? Let us know in the comments section below.