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, 8 July 2010

Day 23

This was not a day to be remembered. We headed toward Dandong, the border town with North Korea and arrived there at lunch time. In an absolute moment of decadence we had a KFC over looking the border (not proud of it!). This was one of those surreal moments where you are not quite sure where you are.Someone tells you that behind the Chinese flag the coastline is a country where a few million people are suffuring daily and you are swamped by an inevitable feeling of voyeurism and guilt about being on the good side of the fence.
Reloaded with our Americanised lunch we headed up towards the mountains. Yes, Fred China is a big country (no actually it is huge!) and to get to a place and get our fish we need to drive long distances. As part of our study we aimed at collecting this small fish from across the geographical range in the native part of China. It was a deliberate choice to go for coverage rather than high resolution in one location. Anyway, we found a lovely river in the mountains but our fish was not there or according to the locals very low in number. I suggested to Yahui that we should check the reservoir as it is the place where our fish normally do best but we had to pay to get in and he refused saying that was not a good location to fish. So we spent most of our afternoon trying to find such good location but without success. At the end of the day we met a couple of local fishermen who told us that the only place to get the fish as they were abundant was the reservoir… (very frustrating). Anyway, this was not an easy moment as losing face is not part of our host's tradition so we headed up to a local hotel and for some dinner (Californian noodles, equivalent to McDonalds in China during the 80’s). By the way,for dinner the hotel was offering some giant living worms (or parasites) which was not my cup of tea. After dinner, Yahui said “I have an idea why don’t we go and fish the reservoir after dinner as it is still open”…but after further lengthy diplomatic talks we headed up towards the local river to fish and caught…nothing!
We went back to our room exhausted from a frustrating day and felt that the day had escaped us without having been able to do much.
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