August 5, 2012
Ultimate Survivor Title Goes To The Red Swamp Crayfish
redOrbit Staff & Wire Reports - Your Universe Online
Could make you think twice about introducing them to ecosystemsResearch from Queen Mary, University of London has found one of the most invasive species on the planet earth is able to source food from the land as well as its usual food sources in the water.
Scientists examined the behavior of red swamp crayfish in Kenya's Lake Naivasha and discovered that the crayfish found additional food sources on land when the water was low in the lake. The study was published in the August issue of the journal PLoS ONE.
"These crayfish are incredible survivors; our research shows they are able to feed off terrestrial plants directly, as well as aquatic plants — the first study to demonstrate this," explained Lead author Dr. Jonathan Grey from Queen Mary, University of London.
"It has significant implications for anyone looking to introduce these species in other areas."
A technique called stable isotope analysis was used by the research team to look at the diet of the crayfish. They used a natural chemical signal of diet in the species' tissues to determine what they were consuming.
They found some of the crayfish population had left the main lake and were surviving by burrowing in small pools of water that formed in the footprints from hippos. The crayfish clambered out from the footprints after dark and grazed on the surrounding terrestrial plants.
"This study demonstrates how the red swamp crayfish is such an extraordinarily successful invader," Dr. Grey said.
To enhance fisheries and to attempt to control populations of snails which carry a parasite causing river blindness in humans, the red swamp crayfish has been introduced to multiple locations throughout East Africa since the 1960s.
"While they are useful to counteract other harmful species in ecosystems, they are also extremely damaging to fish populations and the balance of the food web. They eat plants, fish eggs, fly larvae, snails and leeches and since we have now shown that they are able to tap into extra resources from the land, they can sustain higher populations under adverse conditions such as low water and could cause more of a problem in a variety of environments than we initially thought."