Use of grass carp (Ctenopharyngodon idella) as a biological control agent for submerged aquatic macrophytes

Abstract

-This study aimed to evaluate feed preference and control efficacy of grass carp (Ctenopharyngodon idella) on the aquatic macrophytes Ceratophyllum demersum, Egeria densa and Egeria najas. An experiment was carried out at mesocosms conditions with 2,000 liters capacity and water residence time of 2.8 days. C. demersum, E. densa e E. najas biomasses were offered individually with sixty g and coupled in similar quantities of 30 g of each species, evaluated during 81 days, envolving 6 treatments.(1 -C. demersum, 2 -E. najas, 3 -E. densa, 4 -C. demersum + E. najas, 5 -C. demersum + E. densa and 6 -E. najas + E. densa). When offered individually, E. najas and C. demersum presented the same predation rate by grass carp, which was higher than E. densa predation rate. When plants were tested in pairs, the order of feed preference was C. demersum > E. najas > E. densa. E. najas and C. demersum percentage control ranged from 73 to 83%. No relation between biomass consumption and grass carp body weight gain was observed, probably due to differences in nutritional quality among macrophyte species according to fish necessities. Therefore, it is concluded that the use of grass carp is one excellent technique to control submersed macrophytes in Brazil. Keywords: feed preference, Egeria najas, Ceratophyllum demersum, Egeria densa. RESUMO -O objetivo deste estudo foi avaliar a preferência alimentar e a eficácia da carpa-capim (Ctenopharyngodon idella) no controle das macrófitas aquáticas submersas

Pengendalian biomassa giant salvinia (Salvinia molesta) dengan grass carp (Ctenopharyngodon idella)

“…Chilton and Muoneke (1992) mengemukakan bahwa popularitas penggunaan grass carp sebagai agen biokontrol tumbuhan air berkaitan dengan kemampuan dan daya tahan tubuhnya, mudah dibudidayakan, kontrol biologis yang efektif untuk berbagai tumbuhan air, serta sebagai sumber protein yang berkualitas tinggi. Faktor-faktor yang mempengaruhi tingkat kontrol vegetasi dengan grass carp adalah padat tebar ikan, iklim regional, serta kelimpahan dan komposisi spesies tumbuhan air (Garner et al 2013;Silva et al 2014).…”

“…Karena pengurangan efisiensi pencernaannya, grass carp mengonsumsi banyak vegetasi (Masser 2002). Silva et al (2014) menggunakan grass carp dalam penelitiannya sebagai agen kontrol biologi terhadap beberapa makrofita air di Brazil, diantaranya Ceratophyllum Demersum, Egeria densa dan Egeria najas. Hasil yang ditunjukkan dalam penggunaan grass carp terhadap preferensi pakan pada makrofita tersebut secara berturut-turut yaitu C. demersum sebagai preferensi pakan tertinggi, selanjutnya adalah E. najas dan E. densa.…”

Effects of Water Temperature on Growth Criteria of Fingerlings of Grass Carp, Ctenopharyngodon idella (Valenciennes, 1884)

“…Durborow et al (2007) stated that grass carps are used in water ponds to consume undesirable aquatic vegetation and filamentous algae. Silva et al (2014) stated that grass carp is used to control aquatic plants in Brazil. Dick et al (2016) revealed that 120 individuals of grass carp per hectare gave better control for plants in the lakes.…”