Comparative study of parasitic loads of Callinectes amnicola and Cardisoma armatum from two major river systems in Rivers State, Nigeria

Abstract

The consumption of sea food especially crabs in the Niger Delta is an indelible aspect of the culinary culture of the people and a veritable avenue to contracting zoonotic infections. A comparative analysis of the parasitic fauna status of two edible crabs; C. armatum from the New Calabar River and the marine crab; C. amnicola from the Elechi Creek was conducted from March to June, 2016. The physico-chemical parameters of the water samples were determined using standard techniques. The samples were dissected and the hemolymph, the appendages, gill, mouth parts and eye, carapace and gastrointestinal tract (GIT) examined. 147 samples of C. amnicola  comprising of 79 (53.74%) males and 68 (46.26%) females were sampled while 123 samples of C. armatum comprising of 59 (47.96%) males and 64 (52.03%) female were also sampled. Data revealed that out of the 147 C. amnicola sampled, 61(41.49%) were infected while 63 (41.50%) were infected out of the 123, C. amnicola  sampled. Sex related prevalence showed that C. amnicola, females had higher prevalence when compared to the males. However, C. armatum, males had a higher prevalence when compared to the females although the prevalence between the sexes was not statistically significant (p>0.05). There was variability in the parasite load across the sets of infections with the gastrointestinal tract, hemolymph and gills while the least infected sites were the mouthparts/eyes and appendages in both species of crabs. Also, protozoa had the highest prevalence in C. amnicola  while nematodes had the highest prevalence in C. armatum. There were also variation in parasitic infection in relation to weight, width and length. The study is of the opinion that blue crabs and land crabs from new Calabar River and Elechi Creek were heavily infected with parasites and should be adequately cooked before consumption. The study also opines that public awareness campaigns should be more regular to educate the riverine residence on current waste management strategies.