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. :-)

Tuesday 22 June 2010

Day 7

We are getting tired as we normally wake up at 5 am and do not go to bed before 12 midnight. We catch up with sleep in the car but it is not enough. Fish prove to be harder to catch than expected due to flooded rivers but we keep focused and I will have to make some key descisions about our sampling strategy.Breakfast, which consists of hot dishes (beef, duck etc.) rice, dumplings and rice soup is becoming harder and harder for us to face. I have never been very fussy about food but I have always taken cheese, fruit, coffee and orange juice for granted...my mistake. Tonight before dinner we found some local fisherman who have accepted to set our traps, we will check them tomorrow morning. I hope to have more luck than our football team, I am not domenech so the jury is still out.Tonight with the meal we had a rice spirit which had a poisonous snake marinated in it (58o), then we went to have traditional tea served with as much ceremony as for a good Bordeaux.I took a little film that I wanted to put on you tube for you to see but here the site is blocked so when I tried to access it the internet connection crashed! When I rebooted I could only access the Chinese version of Google. Yesterday Yahui said that China was like any other country. Superficially, it resembles an open society but appearances are deceptive, particularly if you try to go deeper for example the internet.
Response to comments:
Isa, the whole of China is a just a succession of aquacultures but the infrastructure is very basic and not suitable for student placement. In addition, the language would be a real barrier. However, an organised visit for them would be an eye opener on how efficient aquaculture takes place. Here most of the fish that Chinese eat are freshwater and not salmonids, very different from France. Lots of freshwater shrimps.Youval, you would love it here, no need to chum heavy to catch tonnes of fish. Good stuff for your catch you are becoming a real pro not only at baseball.Denise, there are so many amazing things on so many different levels that you want to communicate them in real time. It is a bit like when you were little and couldn't keep
a secret!
Posted by Picasa
Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)

You are visitor number