In Lithuania, the movement of some wild boars is observed with the use of GPS transmitters

This is the third year that the State Food and Veterinary Service (SFVS) has participated in the international project “Defend”, which is based on the partnership of international scientific, industrial and governmental organisations. Industries are seeking to find new ways and methods for controlling African swine fever (ASF), to acquire new knowledge of the course of this disease and possible eradication methods. Lithuania is taking part in the project activities related to ASF prevention, management and control at pig production farms as well as in the wildlife, i. e. among wild boars.

The project seeks to better understand properties of the ASF virus and ways of spreading among wild boars, to determine the distances at which the infection can be transmitted to other wild boars in a natural way, to record the movement of wild boars on the 24-hour basis, the distances that are covered by those animals in infected areas, and what are the probabilities of contacts between different wild boar groups in terms of transmitting the virus. For this purpose, wild boars in ASF infected areas from different age groups and of different sex have to be caught and marked with the use of special collars containing Global Positioning System (GPS) transmitters. With the help of GPS, data on the movement of wild boars within units of hunting areas in different seasons will be systematised, information on the living areas of wild boars and the range of their movement will be collected. Those tasks are planed to be accomplished in Lithuania by the end of 2021.

To achieve that purpose, last year, specialists of the SFVS, having received consent from users of the hunting areas and a permission of the Environmental Protection Agency, installed 9 live catch traps for wild boars in Kaunas, Kaišiadorys, Trakai and Vilnius district municipalities, in a unit of Karalgiris professional hunting areas, units of the hunting areas of Žiežmariai hunting club, Skala hunting club, Trakai regional division of the State Forest Enterprise and Jovariškės hunting club “Elnias”. 

In the above areas, wild boars were lured in order to catch and mark them. In 2020, 22 wild boars were caught (20 of them were marked with yellow ear tags containing the phone number, which had to be called by the hunter who had hunted such a wild boar, to report the exact coordinates where the wild boar was hunted, and with special collars for wild boars with GPS transmitters).

It should be noted that the caught wild boars were partly anesthetized to avoid their stress or injury at the time of marking. Collars with GPS transmitters of different producers (Spanish, German and Lithuanian) transmitting information on the location of the wild boars up to 48 times per day were used for marking wild boars. In the units of hunting areas where wild boars were caught, marked and set free again, no hunting restriction actions were applied.

Out of the 20 marked wild boars (ten females and ten males) 2 wild boars have already been found dead. Tests of the carrions did not show that the animals had died from ASF, however, they failed to identify the exact cause of the deaths. One of the wild boars was found shot (as a result of likely poaching), 3 have been hunted, 2 dropped their collars, whereas collars of 5 other wild boars no longer transmit any signals most likely because of some technical problems in transmitters or because of large amounts of data recorded in the inner memory of the transmitters, therefore, the wild boars were asked to be hunted to ascertain that the information, which can be used for further analysis of data on wild boar movement, is being recorded by the transmitters.

In 2021, 10 more wild boars are planned to be additionally marked both with ear tags and collars with GPS transmitters. This quantity would be sufficient for data analysis and for obtaining certain results and making conclusions.

Therefore, the SFVS would like to address hunters in Lithuania with a request to communicate information by the phone, which is indicated on the ear tag, in case a marked wild boar is hunted, and to take off the collar with a GPS transmitter carefully and deliver it to the nearest territorial unit of the SFVS.