Slaughtering Practises in Fishing: A savage affair?

wmusselI am an avid angler, and there is nothing I love more than fishing recreationally, and from time to time taking a fish home for the pan. Before this article continues I would like to make it inherently clear that I am not pointing fingers and looking for fishing practices to change. I just want to share some knowledge that I have gained in my studies as an Ichthyologist and Fisheries Scientist that have made me rethink current fishing practices and the way in which I handle fish when I intend on eating them.

Fish are hauled up onto beaches, banks and boat decks on a day to day basis, and very often left to suffocate. The manner in which fish are left to die over a long period of time is very seldom met with much opposition from people. If there is any disapproval shown, the immediate rebuttal is “it’s ok, it’s just a fish, it has no feelings”. This statement has been taught to children, resulting in what I believe are inhumane fish killing practices continuing.

There seems to be a social impression, that the bigger the animal, the more painful it is to watch that animal die, as it must have more “feelings” than a smaller animal. However if it came down to a person wanting to save either a dolphin or a tuna of the same size, the dolphin would be saved in a heartbeat.

There was a massive outcry when a documentary called “The Cove” was released, showing dolphins being brutalised in a small bay off of the coast of Japan. The film was met with a massive movement toward eliminating Japanese dolphin fishing practices. In another documentary called “the end of the line”, there is a segment of film taking place in the straits of Gibraltar, where large blue fin tuna are corralled into nets and men with small gaffs impale live fish and drag them over the edges of boats, where they are left to bleed and suffocate to death. This footage seemed shocking to me, and the ways in which the fish were being killed are in the exact same manner as dolphins were in the cove. Tuna are complex animals with an intricate circulatory system that results in warm blood, yet they are slaughtered in terrible ways that are often more brutal than those practiced on mammalian or avian animals. Yet there is no outcry in the current methods that they are harvested.

There seems to be countless shows cropping up on television programmes in defence of marine mammals that are harvested for food, or documentaries exposing bad methods of slaughter in animals destined for fast food chains. However, where are the shows protesting the manner in which large sums of fish are thrown onto decks of vessels? Or a documentary that secretly films the way in which tunas, yellowtail are netted in their scores and left to die?

The problem stems from a lack of scientific research into the question of whether or not fish are capable of fear or feeling pain.  And with this lack of knowledge has come an almost savage way of harvesting and killing fish. I have uncovered some interesting articles and papers in my studies that have made me change the way in which I kill fish intended for eating.

Many commercial fishing groups suggest that fish are unable of pain awareness and some scientific papers support this view. One of the papers in support of the above statement is compiled by James Rose. He conducted experiments on three species of elasmobranchs (sharks or rays), and after dissection he failed to identify nociceptors (nerves for pain perception in humans and other mammals) and concluded that fish do not have the neural apparatus to detect pain. In another review concluding that fish are not capable of pain perception, James Rose defined pain in terms of brain structure and stated that an animal must have the necessary brain structure, a neocortex, to perceive pain. With this definition only humans and primates are capable of experiencing pain. Lynne Sneddon pointed out that this literature expediently ignored the bird and amphibian literature, which has proven that both birds and amphibians are capable of pain, even though they too lack a neocortex.

Lynne Sneddon has recently put forward her own experimental evidence of possible pain perception in fish. These studies demonstrated the presence of nociceptors in fish using neuroanatomy (study of the nervous system).

Nociceptors are receptors that preferentially detect poisonous, damaging stimuli and these nerves have been identified in a wide variety of animals as well as in humans. In an experiment on the rainbow trout, the nociceptors were found on the head of the fish and around the lips and gill cover. These nociceptors had the identical properties and structures to those found in mammals which have been shown to directly perceive pain. She then continued in the paper to carry out experiments where fish were injected with a noxious substance in areas where these receptors were present, and stress behaviours were recorded. Another experiment was used where the noxious substance was injected and morphine (a known pain killer) administered. The latter showed results of a statistically significant decrease in stress behaviour. Morphine has been shown to numb certain receptors in fish that are also present in humans, thus showing that fish have, to a certain extent, the capability of feeling painful stimuli.

Other studies have also been conducted where neurological responses to stress situations have been monitored. These results showed that fish have similar neurological patterns to other animals when exposed to stress and pain. In other words, this means that fish can perceive stress and pain in a similar way to other animals.

I am not trying to say that people should not eat fish nor feel like they shouldn’t keep fish. I, as an avid recreational angler, as well as ambitious aquaculturist would be shooting myself in the foot if I were to make such a statement. However, I feel that we as recreational anglers need to rethink the methods in which a vast majority of us kill fish. I am very often witness to people fishing recreationally now that I have started working with the LBRC, and once the fish come on the bite there is a mad rush to land a bag limit, this results in fish being thrown off a hook and laying on the beach or in the hull of a boat where they take a long time to die.

When I intend on keeping a fish for the pan, I have a method which I follow when slaughtering. The best method in which to dispatch a fish is that of a swift blow to the head followed by the spinal cord being severed (this also bleeds the fish sufficiently). Stress during slaughter (struggling in a net or suffocation) results in more fatigued fish. The muscles of fatigued fish have a lower pH. This lower pH is due to lactic acid build up caused by over exertion. This low pH enhances the action of enzymes present in the muscle that are responsible for the breakdown of protein. One study even claims that stress increases the amount of those enzymes present, as well as making them more effective at breaking down proteins. Finally, tired and stressed fish have less available ATP in their muscles. ATP is the energy source that allows for a fish’s body to function. Once an animal dies, its muscles remain pliable for as long as it has some reserves of ATP. Once the ATP is used up, the muscles tense and will not loosen up –this is called rigor-mortis. Rigor-mortis in fish can be strong enough to tear muscle fibres, leading to soft, mushy meat. Muscles from stressed fish with low ATP reserves go into rigor-mortis faster and can have harder flesh initially, that then goes “off” quicker when compared to fish that are less stressed with more ATP. Therefore it can be seen that a quicker death in fish will result in higher quality, better tasting flesh.

I hope that this article results in better fish killing practices in some fishermen. And that the next time somebody decides to keep a fish it is not just left to suffocate on a beach or deck. We as recreational anglers have a massive impact on fisheries and if we spread good fishing practices amongst ourselves as well as to our children we can conserve a resource that will sustain many generations to come. Remember limit your catch, don’t catch your limit, and we can conserve this precious resource.

 

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