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. :-)

Saturday, 10 July 2010

Day 25

The tiredness is starting to take its toll and itis becoming harder and harder to wake up at 5.3am to go to the local market. We didn’t find many specimens in the early morning market today but yesterday we met someone who claimed he could get us a sample of 100 fish. After receiving no news from this contact we headed off to meet him at the seven family village.When we arrived, there was only his wife, two feet in the mud on the side of a busy road trying to sell a few fish in a bin. A few negociations later she agreed to phone her husband who for a substantial payement finally agreed to go and check his traps…then we got our 100 fish! The fish looked different from other places with the head much smaller in proportion to the rest of their body. Genoveva, the fish are preserved in formalin for parasites, life history traits and morphology but fish are individually marked with a fin clip in alcohol for additional genetic analyses. When possible another sample is preserved in alcohol for parasite study and stable isotope analyses.We processed the fish on the side of the muddy road with over fifty women, children and men attracted from all around to see the foreigners who were so interested in such a small fish. They all made fun of us throughout the processing of the samples but all in a friendly maner. They will never look at this fish in the same way again though…Then we quickly headed on our way back to Beijing as we have a couple of river systems to sample before further work on the Academy collections. The weather was miserable, lots of rain and fairly cold. The distances between any sampling locations are massive. It is a bit like sampling in Paris in the morning and staying in Marseilles in the evening.Throughout our journey we have discovered the rural part of China, with clearly defined climatic regions, with the agriculture of maze in the North , wheat in the middle and rice in the south. We also discovered the highest caused of death for Chinese between 25 & 45 years old…motorways. These are lethal and on many occasions I thought that it would be the end of us. The trucks are all overloaded to such an extreme that the roads are littered with pot holes that a team of legionnaires tries to repair every day.Tonight we are staying in Kangping, a somewhat rundown town in the North of Shenyang (Liáoning Province). Here people are more discrete in their surprise of seeing foreigners walking their streets. When they have a chance they ask Yahui where we come from and he replies in a debonaire style ‘Ingua’ meaning England.We will all welcome some sleep as we have agreed on a 5.30am morning (although the hotel manager recommended going to the market at 4…!)
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