NO20151709A1 - Elastic net for removing parasite on fish - Google Patents

Abstract

Net of elastic material that is exposed as a barrier in cages, rivers, lakes or seas. The net encloses the fish's body as it swims through, which causes the parasites to peel off the fish body, be damaged and swim freely in the water. The network may be permanently installed, so that parasites that find a new host will be peeled repeatedly, which will cause them to not get their necessary nutrition. The parasites also do not multiply and the population of parasites dies out in the long run.

Description

Description

Net for the removal of parasites on fish

The invention consists of a net made of elastic material for the removal of parasites on fish. The invention is for use in fish farms, rivers or free-floating in the ocean or sea.

The aquaculture industry in Norway and the rest of the world has a huge problem with parasites that appear on fish in the aquaculture facilities. In particular, Salmon lice (Lepeophtheirus salmonis) and Scots lice (Caligus elongatus) are two species that cause problems for the farming industry.

Salmon lice cause damage to salmon by feeding on mucus, skin and blood. This opens the door for other infections from, for example, bacteria and fungi and also affects the osmotic salt balance of the fish.

Lice are one of the most important causes of loss in salmon farming today. Roughly speaking, the Norwegian farming industry loses around NOK 500 million annually in direct losses (Edited by the inventor: the figures here are from 2009, the estimated cost for the industry in 2016 is over NOK 8 billion), expenses for chemical use and extra work for de-lice, weight loss due to stress, possible loss of fish, etc. There are now clear limits on how much salmon lice salmon can have in farms. The Norwegian Food Safety Authority has clear guidelines for how to combat the parasite.

Wild salmon get into trouble when more lice are produced. The primary effect of salmon lice is reduced growth. Reduced growth in weak, wild populations can in the worst case lead to a weakening of the reproductive potential.

Source: The Norwegian Institute of Marine Research's theme pages on the internet,

http://www.imr.no/temasider/parasitter/lus/lakselus/nb-no

Existing solutions for parasite removal in farmed fish have until now mostly been drugs, which has started to result in, among other things, resistance in the parasites.

Recently, flushing of fish has also been introduced, a method which involves the fish being physically taken out of the cage, flushed and returned. The parasites are collected and destroyed. This method is expensive, resource-intensive and contributes to stressing the fish, which in turn has an impact on the quality of the meat, and not least the animal welfare of the fish.

There are also solutions where the fish themselves have to seek out installations in the cages to scratch off the lice, the effect of these is not known to the inventor.

The invention consists of setting out an elastic net (Figure 1.) as a barrier in the water, which means that the fish itself removes parasites every time it passes through the net.

In a limited area, for example a cage, the fish constantly swims in a circle, and will pass through the net at regular intervals. Due to its elasticity, the meshes in the net will stretch and tightly surround the fish's body (Figure 4).

The fish, e.g. salmon swim at speeds of 0.2 to 1.9 fish lengths per second (Havforskningsrapporten 2010), which means that the parasites are peeled or almost planed off the fish's body due to the fact that the net, which is tightly wrapped around the fish's body (Figure 2-6.) is quickly pulled over the parasites and breaks their connection to the fish. This is achieved whether the parasites have bitten, sucked or attached themselves in other ways. The parasites will probably also be damaged to a large extent by this treatment. Those that do survive will quickly have to find a new host. Since the net can remain permanently in, for example, a cage, the sequence mentioned above will repeat itself (Figure 2-6) the next time the fish swims through the net, and in the long run the population of parasites will die out by itself as they cannot be eaten or reproduce in his usual way.

One of the reasons for the large amounts of parasites that exist now is that they have too good living conditions in and around breeding facilities, where there are hundreds of thousands of individuals to live on. The invention affects the entire life cycle of the parasites, and destroys the good living conditions for the parasites, so that they will eventually die out.

The invention is environmentally friendly, gentle on the fish, no added energy is necessary, the fish does the work itself over time. No use of drugs. The invention creates no waste products, apart from dead parasites for a period of time, which will be taken up by the sea in the same way as other biological remains from plants and animals.

Claims (7)

1. Net for the removal of parasites, characterized by the fact that it is composed of elastic thread (Figure 1.) 2. Net according to claim 1, characterized in that it surrounds the fish's body so that parasites are peeled off when the fish passes through the net. (Figure 2-6.) 3. Net according to claim 1-2, characterized in that the thread in the yarn consists of material that can be extended by more than 1% of its own length 4. Net according to claims 1-3, characterized in that it is assembled as a fishing net with large or small mesh sizes, depending on the size of the fish to be treated 5. Net according to claims 1-4, characterized in that it is made of wire with a thickness adapted to the size of the fish to be processed 6. Net according to claims 1-5, characterized in that the meshes on the net have a shape that is adapted to the size and type of fish to be processed 7. Nets which, according to claims 1-6, are characterized by being placed in the sea as a barrier for the fish, so that it must actively swim through the net