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. :-)

Sunday 11 July 2010

Day 27

Today is a special day as it is our last sampling day. We have so far managed to get 15 samples well spread across China, so the pressure is off and we can start to relax. We started the day with a European type breakfast (ie. Coffee, cereals, yougourts, fruit, cakes & orange juice!). We went down to the local market on board a local taxi - a sort of Dell boy three wheeled vehicle. At the market for the first time since our arrival there were no live fish…all frozen. This is because all the local rivers are dry. We travelled for an hour to the next city and again no fish as all the local river are dried up. It is heartbreaking to see large rivers without any water, not a drop. Especially as rivers are the life blood of Chinese society. The causes of such an environmental disaster are unclear but one thing is certain, it is not going to get better with the cities increasing at such a fast pace. According to Yahui, the government plans to bring water from the south to the north through a system of canals. So no water no fish. On the way back, I asked to stop to take a picture of these dry rivers that I could use later for a lecture. A guy came from nowhere to ask what we were doing, then he mentioned an old small reservoir at the top of the mountain and we decided to pay a visit. After a couple of kms of dirt track where the car nearly sunk in the mud, we arrived at the top of the mountains to find a small reservoir (i.e. essentially a large pond) where local teenagers were fishing with home made fishing rods cut from a tree. The reservoir seemed full of fish and the kids had caught..our topmouth gudgeon! Excited we set up some traps and after 30 mins they were holding hundreds of topmouth and nothing else.Life is so strange. On our last day on a lucky stop we were directed to this quiet stunning place in the middle of nowhere, and after so many difficulties finding our fish during the expedition, it was right there waiting for us in its thousands. The fish have been isolated in the reservoir for over 30 years, very similar to our topmouth population in the UK. The circle is now closed, we are heading back to Beijing where we are preparing ourselves for a long day tomorrow, processing the collection of the Chinese Academy of Sciences.
Rudy
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2 comments:

  1. Anonymous12 July 2010 at 05:47

    Great football match! So much excitement that I had to leave the room from time to time! Well done on them!
    Good luck for the rest of the trip - I do hope everything goes as you have planned. Safe journey back home. All best wishes Genoveva

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  2. Anonymous12 July 2010 at 06:04

    Mon cher Rodolphe, nous sommes à Crasville et il nous est plus difficile de suivre tes aventures chinoises...
    Nous avons bien l'intention de te mettre à la question pendant notre moment ensemble, ici même, un petit verre de vin blanc à la main et des enfants qui gambadent autour.... Un petit vent frais rafraîchit nos peaux bronzées et patati et patata en tous cas, ce sera super coooooooolllllll....
    En attendant, je (on) t'embrasse bien fort...
    Mille pensées.
    Fabienne

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