A Review of Freshwater Crayfish Introductions in Africa

Abstract

This review summarizes and analyses information on freshwater crayfish introductions in Africa. A total of 136 research papers and reports were found to be relevant. Forty-eight percent reported presence; 21% described negative impacts; 11% referred to potential socio-economic benefits; 9% evaluated control measures; 6% documented co-introduced parasites. Out of nine introduced crayfish species, five species Astacus astacus, Cherax quadricarinatus, Faxonius limosus, Procambarus clarkii, and Procambarus virginalis have established populations in the wild. Astacus astacus and F. limosus are present only in Morocco and P. virginalis is limited to Madagascar. Cherax quadricarinatus and P. clarkii have established populations in five and six countries, respectively. The main driver of crayfish introductions was to provide socio-economic benefits through aquaculture and fisheries development but there is limited evidence of success. Prevailing negative socio-economic impacts are linked to damage to agricultural water infrastructure, damage to fishing gear and declining fisheries performance. Ecological impacts pertain to direct and multi-trophic consumptive effects as well as indirect competitive effects primarily upon macro-invertebrates and potential spillover of parasites to other decapods. Research priorities are determining abundance, distribution and spread of crayfishes and assessing ecological impact to inform management decisions.

Invasive crayfish outperform Potamonautid crabs at higher temperatures

“…Africa has been a recipient of nine crayfish species introductions, the two most invasive species, Australian redclaw crayfish Cherax quadricarinatus (von Martens 1868) and Louisiana red swamp crayfish Procambarus clarkii (Girard 1852), are spreading rapidly across the continent (Madzivanzira et al., 2020). The main driver of crayfish introductions was to provide socio‐economic benefits through fisheries development and aquaculture but there is limited evidence of success (Madzivanzira et al., 2020). Cherax quadricarinatus is native to Northern Australia and south‐eastern Papua New Guinea (Riek, 1969).…”

“…Cherax quadricarinatus is native to Northern Australia and south‐eastern Papua New Guinea (Riek, 1969). In Africa, C. quadricarinatus has established feral populations in parts of Mozambique, South Africa, Swaziland, Zambia, and Zimbabwe (see Madzivanzira et al., 2020). Procambarus clarkii is native to southern and south‐eastern U.S.A. and northern Mexico (Hobbs, 1972).…”

“…quadricarinatus and P . clarkii on southern African ecosystems are not well documented (Madzivanzira et al., 2020). In Africa, prevailing negative socio‐economic impacts of P .…”

First record of the Australian redclaw crayfish Cherax quadricarinatus (von Martens 1868) in Hong Kong, China

“…Cherax quadricarinatus is a large and conspicuously coloured crayfish native to south-eastern Papua New Guinea and northern Australia (Jones 2011). Cherax quadricarinatus has been introduced to many countries around the world for aquaculture, fisheries and ornamental pet trade (Ackefors 2000; Belle et al 2011; Lodge et al 2012; Faulkes 2015; Madzivanzira et al 2020). Escape from captivity and deliberate release by pet owners has resulted in the establishment of feral populations globally (Lodge et al 2012; Madzivanzira et al 2020).…”

“…In Hong Kong, C. quadricarinatus may compete with functionally similar native decapods such as Macrobrachium hainanense , M. nipponense , and Nanhaipotamon hongkongense . Unfortunately, outside of South Africam studies on the ecological impact of C. quadricarinatus is severely limited (Madzivanzira et al 2020; Morningstar et al 2020). Pinder et al (2019) suggested that this species may deplete macrophyte cover and alter invertebrate communities in Western Australia, while Williams et al (2001) suggested it may out compete and replace freshwater shrimp in Puerto Rico.…”