Occurrences of the Macroinvertebrates in the Alimentary Canal of the Mangrove Oyster- Crassostrea tulipa (Family: Osteidea)
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Date
2025-04
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Faculty of Science, Gombe State University
Abstract
The food contents of the mangrove oyster, Crassostrea tulipa (C. tulipa) from Tomaro
mangrove swamp of the Lagos Lagoon were investigated monthly from January to December,
2022, using one hundred samples for each month. The stomachs were gutted and its contents
examined under the microscope using frequency of occurrence and numerical methods for food
items while the vacuity and fullness indices were calculated using standard formulae. The results
revealed that the species feed on various food items of both plants and animal origins with dietary
preference consisting of Closterium ehrenbergi, Detritus, Melosira varians, Navicula elliptica,
Oscillatoria tenuis, Nitzchia gracilis and organic substrates. Of the 1200 stomachs examined, 346
were empty stomachs, 292 had quarter-full stomachs, 170 had half-full stomachs, 287 had three
quarter-full stomachs and 107 had full stomachs, indicating that there were significant differences
in different months (P<0.05). The study on the food items in the stomachs of C. tulipa indicated
that they ingested a variety of benthic and pelagic food resources, mainly phytoplankton,
suggesting therefore that C. tulipa is a phytoplankton feeder, mainly consumes aquatic insects,
algae, diatoms, and organic decay material with modest feeding throughout the year while animal
derivatives, aquatic plants and gastropods were eaten accidentally.
Description
Keywords
Food items, fullness index, oysters, vacuity index