REDCLAW - AN AQUACULTURE JEWEL OR INVADER ?


The introduction of invasive alien species through aquaculture has been documented, and these species have contributed to biodiversity loss globally. An invasive species is an organism that, after being translocated and brought outside its own natural habitat by humans, can establish, flourishing, and spreading, frequently wreaking significant ecological or socioeconomic damages. Long-distance trading has been particularly successful in breaking down biogeographic boundaries, with humans purposefully introducing certain species and hitchhiking with others (Havel et al., 2015).



There are several documented examples of animals that have already been relocated and have produced environmental and socioeconomic difficulties in their new habitats such as the tilapia, a cichlid from which a selected few species which is an important aquaculture product. Yet, tilapia is now discovered in the wild in several nations, presumably because of their popularity as a food product. Besides that, how it happened with the signal crayfish Pacifastacus leniusculus and the red swamp crayfish Procambarus clarkii, which were widely translocated across the globe to replace the demand of declining native crayfish populations and were used for aquaculture, stocks, or wild capture, should serve as an example and as a warning (Haubrock et al., 2021). The case of the red claw, on the other hand, continues and might go much further.



The red claw Cherax quadricarinatusis (Photograph by: Tan Heok Hui)



The red claw Cherax quadricarinatusis (figure 1) is a parastacid crayfish endemic found in tropical and subtropical freshwater habitats in northern Australia and southern New Guinea. It has been a target species for the aquaculture business and pet trade due to its broad environmental tolerance, quick development, early maturity, high fecundity, gregariousness, overall non-burrowing habit, and high output of "tasty meat." There have been several documented examples of species being relocated and causing environmental and socioeconomic difficulties in their new environments. Most islands in Oceania (such as New Caledonia, Fiji, and Samoa) and Africa such as South Africa, Zambia, and Zimbabwe have acquired red claws for aquaculture. This was even introduced in tropical and subtropical nations from the Americas, including Mexico, Ecuador, Cuba, Jamaica, and Argentina, as well as Asia, including Israel, Indonesia, Malaysia, Thailand, and China, to conduct experimental trials on its possible use in aquaculture. This species has invaded and expanded widely because of escapes from farms, aquarium releases, baiting buckets for recreational fishing, or purposeful stocking (Oficialdegui et al., 2021).




Aquaculture production is therefore possible, but this species also poses a serious environmental and socio-economic challenge in non-native environments. Only a few invaded regions have been examined for these effects. Redclaws pose a serious threat to native ecosystems when they escape aquaculture operations such as earthen ponds, based on past experience with other invasive crayfish and their unique features. Due to extensive research into this species, knowledge of the history of other crayfish species invented to other regions and their fateful implications today, and consideration of the economic benefits of this species' culture, especially for local economies and communities, the severe implications this species can have should not be overlooked, but rather taken into consideration (Haubrock et al., 2021).


In conclusion, the above-mentioned threats created by the red claw, invasive crayfish pose both direct and indirect risks to native biodiversity, say some experts. Yet aquaculture would be impossible without red claws owing to its direct and economical nature. Escapes may occur, and they can result in permanent harm in the context of frequently "regionalized" companies. All of these should be considered by aquaculture businesses when building up red claw productions. Establishing aquaculture in closed facilities requires an integrated strategy to risk assessment and breeding to prevent accidental escapes and protect freshwater biodiversity.




REFERENCES

Havel, J. E., Kovalenko, K. E., Thomaz, S. M., Amalfitano, S., & Kats, L. B. (2015). Aquatic invasive species: challenges for the future. Hydrobiologia, 750(1), 147-170.


Haubrock, P. J., Oficialdegui, F. J., Zeng, Y., Patoka, J., Yeo, D. C., & Kouba, A. (2021). The redclaw crayfish: A prominent aquaculture species with invasive potential in tropical and subtropical biodiversity hotspots. Reviews in Aquaculture, 13(3), 1488-1530.


Oficialdegui, F. J., Haubrock, P. J., Kouba, A. (2021). Are we making the same mistake again? The redclaw crayfish, a prominent aquaculture species introduced worldwide. 47. 30-32.


Photo credit: https://www.researchgate.net/figure/Cherax-quadricarinatus-lateral-view-of-male-Upper-Peirce-Reservoir-Singapore-Total_fig2_224771893



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