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Rothbard, S., I. Rubinshtein, and W. L. Shelton, 1996. The Black Carp, Mylopharyngodon piceus, as a Biocontrol of Freshwater Molluscs, YAFIT Laboratory, Fish Breeding Center, Israel, University of Oklahoma Abstract from The Sixth International Zebra Mussel and Other Aquatic Nuisance Species Conference, Dearborn, Michigan, March 1996 The Black Carp, Mylopharyngodon piceus, as a Biocontrol of Freshwater MolluscsThe malacophagic black carp, Mylopharyngodon piceus is a large and fast growing cyprinid, native to the southern regions of the Chinese mainland (Amur basin). Black carp mature at the age of 7 to 9 years in subtropics (e.g. Israel), which is 3 to 5 years earlier than in China. Mature, 8 to 12 kg fish require warm water and special food prior to artificial, hormonally induced reproduction. In nature, juvenile and adult black carp feed exclusively on molluscs; thus, it has a great potential as a biological control of nuisance snails and bivalves. In preliminary experiments carried out in aquaria, black carp yearlings of 20-50 g easily shifted from artificial pelletized food to a diet of Bulinus sp. The predator/prey relationship, as expressed in black carp gape and snail shell width (for Lanistes, Bellamya and Bulinus spp.), was also shown in other aquaria experiments (Shelton et al., 1995). Black carp stocked into the open reservoirs of the Israeli National Water Carrier (Leventer and Teltsch, 1990), almost totally eradicated fresh water snails (Bulinus, Lymnea, Melanopsis, and Melania spp.) and bivalves (Corbicula sp.). Since the black carp is an effective mollusc predator, it can be considered for biocontrol of mollusc, that serve as intermediate host for human parasites (e.g. schistosoma), or parasites relevant to fish culture, such as the yellow and white grubs in channel catfish and stripe bass farming (Mitchell, 1995). Introduction of exotic species is becoming increasingly regulated by governmental authorities to prevent biological and ecological contamination of the environment. Evaluating the introduction of an exotic fish, as the black carp, in an "ecologically safe manner" can involve several options for reproductive manipulation. These include gynogenesis followed by hormonal sex-inversion, or the production of sterile triploids (Rothbard and Shelton, 1993; Rothbard et al. in press). We present a model of potential biocontrol for a freshwater mollusc by black carp. The basic considerations used in the model were predator/prey relationships as expressed in annual energy balance of the black carp, and the extraordinary reproductive potential of the zebra mussel Dreissena polymorpha. The individual zebra mussel energy equivalent was calculated from Stanczykowska (1977). We used the zebra mussel in the model because of the availability of quantitative data for its consumption (Evtushenko et al. 1994). According to experiments conducted in Russia, 4-year-old black carp ate between 1.4 and 1.8 kg/day of zebra mussels which were supplied to the fish in ponds. We used the equations proposed for common carp by Winberg (1956): (a) Q = 0.343•W0.85 and (b) 0.8R = Q + P (W = fish bodymass in kg; Q = oxygen demand; R = feeding ratio; P = production of fish bodymass).
Keywords: Biological_control,
Bivalve, Predators |