SECOND YEAR OF SUPPORTIVE BREEDING IN NUMBERS

After a very successful first season of supportive breeding for Triturus carnifex at the breeding station in Podsreda, we tried to continue with the success this year. From the collected eggs, 141 larvae hatched and were released into newly excavated ponds in Jovsi in August and September.

Supportive breeding, just like last year, began with the preparation of the breeding station. In March, we filled 10 75-liter containers and 130 20-liter buckets with water, adding some aquatic plants to each one for creating a suitable aquatic environment for the development of eggs and the life and growth of the larvae. In addition to the suitable environment, we had to ensure an adequate supply of food for the growing larvae. Fortunately, we managed to maintain a culture of Daphnia sp., which are essential food for the larvae, in the pools even over the winter. By the time the first larvae hatched, the Daphnias had already multiplied, and daily meals for the larvae were guaranteed.

The egg collection took place together with monitoring in the Natura 2000 project site Dobrava – Jovsi. In addition to examining 10 newly excavated ponds, we also examined other locations where the presence of the Triturus carnifex had been recorded in the past. From four of those donor locations, we collected nearly 400 eggs during six field days. The first eggs were observed in Jovsi on March 24th, and the last were collected on May 9th. Together with the aquatic plants in which the eggs were wrapped, we transferred the collected eggs to larger containers in the breeding station in Podsreda. Each container was labeled with the location and date of collection, as well as the number of eggs taken.

The first larvae hatched five weeks after the first eggs were collected and the others  followed others shortly after. In the first days after hatching, the larvae rested on submerged plants, but they became more active after a week. At that point we separated each larva into its own bucket to ensure an adequate food supply and prevent cannibalism. In the buckets, the larvae grew and developed over the next three months with daily inspections and feeding.

In August, the first larvae began their metamorphosis into young animals, so we set-up temporary habitats with terrestrial sections in the breeding containers where they waited until release. The first 10 young newts were released into Jovsi on August 4th, and the rest remained in the breeding station for about a month longer to complete their development. The second release took place on September 6th, with 92 young newts returned to the wild, followed by 23 metamorphosed individuals in the next few days The final 16 newts were released on September 21st. Compared to last year, the development of the newts this year was approximately 14 days longer due to lower summer temperatures, indicating how animals adapt to different environmental conditions.

Since all 10 ponds of the LIFE AMPHICON project on the leased land in Jovsi were excavated this year, we evenly distributed the newts among all the new ponds. Simultaneously, this year, we were able to return some of them to the only one of the donor locations that did not dry up over the summer. We released approximately 13 individuals at each location. Before releasing them, we photographed the ventral pattern of the newts, which is unique for each individual. This will allow us to recognize our newts in case of recapture during future monitoring.

On the last warm days, we cleaned up the breeding station and equipment, which are now ready for the next breeding season, as are we.

Photo: A. Bolčina, mag. T. H. Oršanič