Yes, we do not have Crayfish in Nigerian waters. If we do have crayfish in shops, then it is imported or here in the country in another way but it is not in our seas, rivers, or other water bodies. In many Nigerian food recipes and even on the research scene, crayfish is often used to describe what shrimp is. A few years ago, a researcher mentioned that we have erroneously been calling shrimps, crayfish and I have decided to shed more light on the difference between the two.
What is Crayfish? Crayfish, also called crawdad or crawfish, are like little lobsters. They are usually found in freshwater. Mainly found in Australia, North America and New Zealand, Crayfish have many species; 300 species in North America and over 100 in Australia. In South Africa, they have been reared but they are not natives there.
Shrimps on the hand are mostly marine; salt water crustaceans, of course some are found in fresh water. They do not have the claws like crayfish or lobsters. They look alike but they are quite different once you take the time to study them. Like prawns, they are stalk-eyed crustaceans with long muscular tails, long whiskers and slender legs. There are so many species of shrimp. A popular one is the Pandalus Borealis, often called the Northern prawn. Other common types are the giant tiger shrimp and white shrimp.
The names ‘shrimp’ and ‘prawn’ are sometimes used interchangeably. Prawn is sometimes used to refer to shrimps which are big in size, while the small ones are called shrimps but it seems that there are some differences between the two especially in body segmentation and the way they reproduce. Also, their pairs of legs are different; prawns having first 3 of five pairs of legs with small pincers, and shrimps have only two pairs with pincers or claws. Also the legs of prawns are similar in length while that of prawns are not.
In Africa, the only sign we have of crayfish is possibly an invader from Louisiana, voracious specie known as red swamp crayfish that has already invaded waters from Kenya, Rwanda, Uganda, Egypt, Zambia and South Africa. It is being said that this specie can upset the balance of ecosystem. Apart from this, there are no native crayfish species found in Africa.
So how did we end up calling shrimps crayfish? I will like to hear the story. If you know it, please share it. It would be great to hear of this ‘crayfishstory’.
Powell, C.B., 1982. Fresh and brackish water shrimps of economic importance in the Niger Delta. In: Proceedings of the Second Annual Conference of the Fisheries Society of Nigeria (FISON), Calabar, 25th-27th January, 1982, A.A. Eyo (Ed.). Kainji Research Institute, New Bussa, pp: 254-285 (1983).
Holthuis, L.B., 1980. FAO Species Catalogue vol. 1. Shrimps and prawns of the world. Annotated catalogue of species of interest to fisheries. (FAO Fisheries Synopsis, 125 (1), FAO, Rome, Italy, pp: 1- 161.