A fish on the trail of Genghis Khan

In the world of fish Topmouth gudgeon Pseudorasbora parva, a small cyprinid native to East China, has matched and gone beyond the great Mongol invasion, resulting in the vast range expansion covering much of Asia, Europe and now with a foothold in North Africa. The stealth invasion started in the 1950’s with the end of the Chinese civil war (from around 1840 to 1949) which had restricted human population mobility and trade. At that time, there was an increasing need for developing new sources of animal protein and black carp, grass carp, silver carp and big head carp were rapidly introduced from East China especially from the middle and lower reaches of the Yangtze River basin to many other places including Yunnan, Qinghai, Gansu and Xinjiang. This species had been cultured traditionally in East China for a long time with specific culturing techniques. These carp introductions for aquaculture have been the beachhead of topmouth gudgeon’s great escape.

Small in size (maximum length circa 9cm), highly fecund with batch spawning and nest guarding behaviour and highly tolerant to environmental changes, topmouth gudgeon has all the attributes of a successful invader. Its first introduction outside of China was in reservoirs and ponds around the black sea as part of a fish farming agreement between China and the former Eastern block. Following long distances and hitchhiking cross country with movements of carp, it rapidly escaped and colonised local waters, dominating communities in ponds and lakes. Recently identified as a healthy carrier of a deadly non-species specific eukaryotic parasite Sphaerothecum destruens, it now poses a threat to European fish diversity.

Preserved material will be compared to material collected from populations established from the first introduction in each country within the non-native range. Topmouth gudgeon has been introduced for several decades to countries with clear contrasting climatic conditions such as Poland, Italy and Algeria. This will provide a unique opportunity to study adaptation under contrasting climatic conditions. Populations will be compared for their life history traits and parasitic communities as well as their population genetic structure within native range but also across introduced range. In addition, live topmouth gudgeon will be brought back from China and various parts of the non-native range to characterise the reaction norms of different populations along thermal gradients. Individual fitness, measured as the number of reproductive events, size of batches and larval growth will be measured for several contrasting populations under a range of controlled thermal challenges. This will allow the evolutionary and phenotypic shift that has occurred during topmouth gudgeon invasion to be measured.

Beyond the immediate scientific interest this expedition represents a cultural and historical journey where an innocent movement of fish from the East coast to the West part of China has rippled all the way to England 50 years later.

The TEAM

ALL ALONG THE EXPEDITION I WILL KEEP THE BLOG ALIVE SO GET IN TOUCH, ASK QUESTIONS AND I WILL BE AS REACTIVE AS POSSIBLE TAKING YOU ALONG THE JOURNEY. :-)

Thursday, 1 July 2010

Day 16


We have reworked our schedule for the northern part of oursampling. Some stages seemed to far apart to make it realistic. We want to be back in Beijing on the 12th to process the specimens offrom the museum collection.Tonight we have arrived in Danjiangkou which is a relative small city in Chinese terms but bigger than most of our capital cities! This is a city which has sprung from nowhere in the middle of the mountains mainly as the result of the construction of a large ded (see picture). After 2 weeks here none of us can still come to terms with this side of China. I think mentally we were not prepared to see such a modern society and such wealth.
The new driver is getting used to us and we try to teach each others some of our native language...without great success as the Chinese language is so difficult for us to memorise and the voice intonations are so different. In any case it is a good source of fun in the car when Yahui tries to say "Arc de Triumph" and I try to say "Hongzehu Lake Huihe River"

In two days Bernd is leaving us to go back to Beijing and then London. The car will feel empty and we will miss him as he is the one who is most curious about the local food extravaganza. Tonight he was up for snake yesterdayit was frogs. But Rob and I keep reminding him that on the second day he ordered some pig stomach in a brine which after testing a tiny piece he left untouched rambling something like "it doesn't taste like the one I had when I was a child back in Germany" :-)

I've only slept about 3 hours per night in the last three days and I feel pretty rough despite trying to catch up in the car. So now here it is 00h30 and I am going to bed. Tomorrow wake up at 5h45 :-(

Rudy
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