Mongolian Grayling Research Expedition

On September 9^th, a group of 3 Austrian's passed our camps on the Delgermoron. Surprised to see other anglers on the river we had a brief chat on the shore and ascertained they were fishery researchers with the correct science permits to conduct this work. We wished them well on their journey, re-assured the local community ranger that they were indeed legitimate scientists, and requested to be kept informed about the results of their study. Clemens Ratschan kindly gave us the following report.

"We made a 2 week float trip in two Grabner inflatable boats (www.grabner-sports.at) from the very upper reaches of the river down to the town of Mörön, for the purpose of scientific research, in order to survey the fish population by catch and release fly-fishing.

Mongolian Grayling Research Expedition with inflatable Grabner boats. Photo: Clemens Ratschan.

Our goal was to collect genetic samples of fish (mainly grayling, but also lenok, taimen and other species) all along the river course. We therefore took small clips of the caudal fin of our catches, and conserved these in tubes with alcohol. Back at the University of Graz, Austria phylogenetic studies will be done with these samples. The main goals are:

1) To learn about small scale genetic diversity of grayling along the river

2) To learn about the relationships between the Baikal Grayling (Thymallus baicalensis) in the Selenge basin, and the yellow-fin grayling of the Darhat Basin in the very north of Huvsgul Aimag.

Shiskiid Basin 'Yellow Fin' or 'Gold Tail' Grayling. Photo: Clemens Ratschan.

In the Darhat Basin, we were able to collect good samples of the grayling that occur in dense populations in the rivers running into Tsagaan Nuur and Shishkid. The character of the yellow coloured tail is very marked and – along with other characters – separates that grayling lineage from other grayling in Mongolia and Siberia.

Delgermoron - Selenge Basin Grayling. Photo: Clemens Ratschan.

As a contrast, the grayling on the Delgermoron show typical arcticus / baicalensis phenotypes. Unlike taimen, the Delgermoron grayling population is rather slow-growing and reaches small body size (see diagram).

We had special research permission from the Ministry of Nature and Environment. We reached the upper reaches by riding through the protected area with special permission from the Border Police. Here we found low water and some sections of whitewater where it was hard work to pull the boats over all the rocks.

Downstream healthy taimen stocks are found. We were very impressed by the clear water and untouched nature up there. Near one campsite, I was very lucky: fly fishing for Lenok and grayling with a size 2 silvery streamer during bright sunshine, I unexpectedly hooked into a 1.22 cm Taimen and managed to land it with my fly-rod.

Further downstream, we weren't able to catch many more taimen – perhaps as the result of localized over-fishing, or habitat deterioration (gold panning, overgrazing), or perhaps the fish were just not biting.

Underwater Lenok. Photo: Clemens Ratschan.

Nevertheless, the scenic canyons and floodplains of lower Delgermoron offered us good Lenok fishing. In the lower reaches, additional species such as Minnow (Phoxinus phoxinus) and Siberian Loach (Barbatula toni) are found."

Photo: Clemens Ratschan.

Thanks to Clemens for providing this report. We will also be able to pass this on to the local community and rangers, who I am sure will be very interested to learn more about their river and its fish.

Photo: Clemens Ratschan.