MOWI CHILE EVALUATES GARWARE FABRIC AS MECHANICAL BARRIER AGAINST CALIGUS LARVAE

Mowi Chile evaluates Garware fabric as mechanical barrier against Caligus larvae. The analysis that considers retention of larvae, entry of these at different speeds of currents and fixation of copepodites to the fish, results in a high quality fabric that allows the containment of infestations and the passage of water flow, allowing oxygenation necessary natural in salmon farming centres..

The Huenquillahue research centre in Mowi Chile, Region X, has been analysing the retention capacity of Caligus rogercresseyi larvae for months on Garware cloths to be used in skirt as a mechanical barrier in salmon farming centres. This is how the meshes were tested by means of sieves for the forced passage of the water flow with the addition of larvae in the nauplius stage (I-II) and copepodites, evaluated in three aspects: their retention capacity of C. rogercresseyi larvae, estimation of the percentage of entry of larvae at different current speeds and with fish to see the fixation of the copepodites that manage to pass through the fabric. In this regard, from the Mowi Chile health area they indicate that “The effectiveness tests of the fabrics that have been carried out, in conjunction with the Austral University of Chile, for the combat of Caligus, have brought good results and we are considering them within the non-drug management alternatives for the control of this parasite ”.

12 fabric blockages: 99.6% of Nauplius larvae and 99.7% of Copepoditos larvae.

The results of the study carried out by the Austral University, highlight the evaluation of fabric cages in a test channel for the estimation of permeability to the passage of the larvae, registering a blockage of 99.6% of the larvae of Nauplii and 99, 7% of the larvae of Copepoditos, so that they do not enter the cage. In each case, the amount of water used was 340 litres with 3,700 larvae per test, a total of more than 133,800 larvae, where a flow of water was applied at current speeds of 0.5, 2 and 3.5 cm * s-1. Thus, the latest generation Garware X12 fabric is recommended as a mechanical barrier against C. rogercresseyi larvae, has high quality characteristics and allows the passage of water flow, without greater resistance at medium current speeds, which should be favourable. to maximise the natural oxygenation of the farm.

“The Skirts for the prevention of infestation are a physical barrier that surrounds the fish tank cage, based on the X12 fabric that allows the water to flow, preventing the entry of lice. This allows 80 times more water flow than a common fabric for these purposes. The weave of the X12 cloth blocks the entry of the early stages of the parasite and promotes adequate water exchange. It is a non-pharmacological product, as part of the strategies to reduce the use of drugs, whose field experience shows a decrease in the frequency of baths of up to 50%, with a reduction of lice of up to 60%. Thus, we developed a three-dimensional fabric, with an opening of 80 to 150 microns for Norway, and a second generation of 60 to 100 microns for Chile, given that the local sea lice is smaller, thus generating a product applied to the national market ”, he comments. Marcos Jofré, business associate Garware Technical Fibres.

Caligidosis infestation is a growth limiting factor in salmon production in the world, where the use of antiparasitic products has become less and less effective due to the development of parasite resistance. This is how the global focus has been on the implementation of new complementary non-pharmacological control methods such as tarps, in the management of infestations caused by salmon louse.  www.garwarefibres.com