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. :-)

Friday, 2 July 2010

Day 17


We stayed in DanJiangkou four hours south of Xi’an, the terracotta army town. We found some aquaculture ponds outside the town where we set up our nets and went for breakfast, packed up our bags and looked at our traps, processed 15 fish then set the nets again went for lunch, back to the traps for an additional 15 fish. Then we had to hurry as we drove up to Xi’an through the mountains. Temperature when processing the fish reached the 40s and Yahui had to use his new fan to give some breeze. The salty drops of sweat pearling down our forehead into our eyes made processing the fish challenging. It was also the 2nd birthday of my little girl Miriam (the same date as the aniversary of the birth of the communist party in China!). It was difficult not to be with her on that occasion and on the phone she seemed so far away…I guess she was. Tonorrow Bernd is taking the plane back to Beijing where he will spend the weekend. It is sad to finish the trip without our red giant but on the bright side we will have a welcome increase of space in the car!!!
From Danjiangkou to Xi’an you pass a small chain of moutains and on the other side the climate is totally different. Still very hot but no water (Mediterrenean type). All rivers are dried up. This is typica,l too much water in the south and not enough in the north!
In the evening as we arrived very late we were restricted to where we could eat for our last meal with Bernd. We found a little street restaurant (barbecue, few salads and a cold beer ;-) and I started a game where we had to think of an emotion and draw a picture to express it. It was to see if we could communicate our emotions without the language barrier. It was great fun, and the people in the restaurant took part. It doesn’t seem that cultural differences were a barrier to communicating our emotions.He is fascinated by our size and took a picture of us saying that when his son is older he will show him the picture and tell him about this trip and make all possible for his son to go to university. He also said that us all being together was fate…
After a nice evening together we went back to our scruffy hotel where a dead rat was lying on the stairs. Never mind, we are so tired nothing will stop us sleeping.
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