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Red swamp crayfish – Procambarus clarkii – iċ-Ċkala l-ħamra tal-Ilma ħelu

Red swamp crayfish – Procambarus clarkii – iċ-Ċkala l-ħamra tal-Ilma ħelu

An extremely problematic invasive alien species at Chadwick lakes is the Red swamp crayfish. It is indigenous to southern America and northern Mexico. It is typically dark red in colour, with long claws and bright red bumps along the front and sides of the first pair of legs.

Today this species can be found across several continents introduced through the pet trade, where it has become naturalised and invasive in many of the introduced regions. It is most commonly found around warm freshwater habitats, including rivers, ponds, lakes, reservoirs and marshes. Unusual for crayfish, it has been recorded in slightly saline waters and water bodies with very low dissolved oxygen concentrations.

The Red Swamp Crayfish is fast growing and can thrive even in seasonal water habitats, furthermore it is able to tolerate drought for up to 4 months. It quickly reaches weights of anywhere from 30 g to around 55 g (wet weight respectively) and sizes of around 5.5 – 12 cm. long. The general life expectancy for a mature healthy specimen is 5 years, however some individuals have been documented to live slightly over 6 years.

It matures after reaching a length of 6 – 12 cm. and can produce anywhere from 100 up to 500 eggs, depending on size. In cases of environmental stresses females have been know to reproduce asexually (without the need of a male) and re-establish populations within a region. The eggs are around 0.4 mm long and once hatched the offspring remain with the mother in the dug out burrows until they undergo two moult cycles and can then fend for themselves.

The burrowing behaviour of the Red swamp crayfish can be severely damaging to water-course banks. Furthermore its aggressive feeding behaviour can disrupt entire native ecosystems. Dragon flies, beetles, frogs, and their larvae, besides other aquatic species, all fall prey to the Red swamp crayfish.

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