Pachymelania

Abstract: Size and shell species preferences of Clibanarius africanus was determined and compared for most occupied shell in the intertidal area of the Lagos lagoon, between March and August, 2008 at five study sites. A total of 663 specimens of hermit crab in gastropod shells were collected. Shell occupation of C. africanus was limited to gastropod shells belonging to Pachymelania and Tympanotonus spp. The gastropod shell most inhabited was Pachymelania spp, which accounted for 60.96% of inhabited shells, while about 39% of the shell inhabited belonged to Tympanotonus spp. Shell preferences were characterized by shell length, weight and aperture width. Positive and statistically significant correlations were obtained between morphometric characteristic of C. africanus and those of the shells inhabited, suggesting that fitness of shell to crab dimension constitutes mainly the determinant for C. africanus shell utilization. Spatiotemporal variations in the type of shell occupied were not significant in this study. Analysis of the abundance of C. africanus in the study area indicates that, a relatively higher abundance of C. africanus was observed in site 3, due probably to the favourable environmental conditions provided by large percentage of sand fractions in the sediment. From the data recorded in this study, it may be concluded that shell selection by hermit crabs involves individual preferences related to the shell features that best provide protection, survival and opportunity for the enhancement of behavioural attributes that are necessary for the maximization of bio-ecological relationships. (Aderonke Lawal-Are, Roland Efe Uwadiae and Olayemi Ruth Owolabi. Shell selection of the hermit crab Clibanarius africanus (Aurivillus, 1898) (Decapoda: Diogenidae) in the Lagos lagoon: Aspects of behavioural and bio- ecology of benthos. World Rural Observations 2010;2(4):70-78); ISSN: 1944-6543 (Print); ISSN: 1944-6551 (Online). http://www.sciencepub.net/rural .

Abstract: Evaluation of pattern of shell utilization by Clibanarius africanus was investigated in the intertidal area of the Lagos lagoon, between March and August, 2008 at five study sites. A total of 663 specimens of hermit crab in gastropod shells were collected. Shell occupation of C. africanus was limited to gastropod shells belonging to Pachymelania and Tympanotonus spp. The gastropod shell most inhabited was those of Pachymelania spp, which accounted for 60.96% of inhabited shells, while about 39% of the shell inhabited belonged to Tympanotonus spp. Shell preferences were characterized by shell length, weight and aperture width. Positive and statistically significant correlations were obtained between morphometric characteristics of C. africanus and those of the shells inhabited, suggesting that fitness of shell to crab dimension constitutes mainly the determinant for C. africanus shell utilization. Spatiotemporal variations in the type of shell occupied were not significant in this study. Analysis of the abundance of C. africanus in the study area indicates that, a relatively higher abundance of C. africanus was observed in site 3, due probably to the favourable environmental conditions provided by large percentage of sand fractions in the sediment. From the data recorded in this study, it may be concluded that shell utilization by hermit crabs involves individual preferences related to the shell features that best provide protection, survival and opportunity for the enhancement of behavioural attributes that are necessary for the maximization of bio-ecological relationships. (Aderonke Lawal-Are, Roland Efe Uwadiae and Olayemi Ruth Owolabi. Evaluation of pattern of shell utilization in the hermit crab Clibanarius africanus (Aurivillus, 1898) (Decapoda: Diogenidae) in the Lagos lagoon: aspects of behavioural and bio- ecology of benthos. Nature and Science 2011;9(3):7-15). (ISSN: 1545-0740). http://www.sciencepub.net .

Abstract: The potential ecological risk index (RI) was employed to evaluate water quality and sediment pollution of heavy metals in the fish Town Rivers, Nigeria. The propensity of the presence of the heavy metals residue in a common brackish water snail (Pachymelania byronensis) that serves as food for human was also examined. Fine-grained surficial sediments from natural depositional zones were collected using Ekman dredge, pooled together and analyzed for the present of heavy metals. The snail samples were randomly hand-picked from the edge of the Rivers or attached to the substrata from August, 2017 to January, 2018 depicting wet season (August October) and dry season (November January). A total of 144 P. byronensis (24 per station) were sampled for this investigation. The concentrations of the heavy metals concentration in the sediments and snail tissues were analyzed using graphite furnace absorption spectrometry. The order of occurrence of the metal in the snail is Zn > Cu > Fe > Pb > Cd and their levels remain within their permissible safe levels for human consumption as stipulated by the various regulatory bodies. The risk factor for the metals in the sediments revealed that the Rivers is moderately at risk, which may not pose serious environmental threat and health risks to the resident organisms, but may be magnify along the trophic level. Therefore, sensitization of the inhabitants becomes inevitable, since the level is at threshold, above which may be detrimental.