Expert topic: Grass carp

by Rebecca Sherratt, Features Editor, International Aquafeed

Grass carp (Ctenopharyngodon idella), also known as white amur, is a freshwater fish that is reportedly the second-most farmed fish (after silver carp) in the aquaculture industry, with five million tonnes-per-year produced on average globally. Native to Eastern Asia, grass carp can also be found in northern Vietnam and on the Siberian-Chinese border. Due to their popularity grass carp can now be found almost everywhere, having been introduced to the US, UK, Japan, the Philippines, the Netherlands, Switzerland, Poland and Germany, just to name a few. Grass carp can live an average of five-to-nine years, but some have been said to live up to fifteen years old in Silver Lake, Washington, US.

This species can be distinguished by its slightly chubby body and firm lips, as well as dark olive colour that can shift to brownish-yellow on the sides. Their bellies are a paler white colour. Grass carp dorsal fins have between 8-10 soft rays and its anal fin is closer to the tail, when compared to most cyprinids. The grass carp has ridged, pharyngeal teeth that enable it to break down tough plants.
 

Alongside aquaculture, the grass carp has also been brought over to the west for control of aquatic weeds, thanks to its herbivorous diet. The grass carp eat three times their body weight daily, ensuring that they effectively maintain weeds in bodies of water, whilst also growing big and meaty as a result. Grass carp thrive in backwaters, ponds and small lakes that are brimming with dense aquatic vegetation but may also sometimes ingest insects and detritus (dead particulate organic materials).

10,000 tonnes of grass carp were farmed in 1950, which increased significantly into 100,000 tonnes by 1972. In 2002, 3,419,593 tonnes were farmed, 95.7 percent of this total number gathered from China alone. In 2016, this number again increased to 6,068,014 tonnes.

Read more, HERE.

The Aquaculturists

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