Student Summer Scholars


Using Crayfish to Control Zebra Mussel Populations

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The expansion of zebra mussel distribution into inland waterways of North America has created significant abiotic and biotic challenges. Zebra mussels foul a wide array of submerged substrates including rock surfaces, plants, native bivalves, dock walls, and watercraft. Fouling of water intake pipes and associated installations can severely impair water delivery to hydroelectric, municipal and industrial users making proactive or reactive control measures necessary. Mussels increase water clarity by removing suspended clay, silt, bacteria, phytoplankton, and small zooplankton. This focuses nutrients into the bottom of lakes away from much of the food chain and also causes increases in cyanobacterial toxins due to increased growth of blue-green algae. However, mussels are exploited by a host of predators, most notably waterfowl, fish, and crayfish. They can return some of the nutrients to the food chain, but unfortunately even with predation much of the nutrients remain at the bottoms of lakes. We have tested one crayfish species (Orconectes propinquus) for feeding responses when given an opportunity to interact with zebra mussels (5 consecutive days). Crayfish did ingest zebra mussels and males ate more than females. Moreover, all crayfish selected smaller zebra mussels as a preferential prey item.