The Importance of Mangroves, Mud and Sand Flats, and Seagrass Beds as Feeding Areas for Juvenile Fishes in Chwaka Bay, Zanzibar: Gut Content and Stable Isotope Analyses
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Date
2006
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
The relative importance of bay habitats, consisting of mangrove creeks and channel, seagrass beds,
and mud and sand flats, as feeding grounds for a number of fish species was studied in Chwaka
Bay, Zanzibar, Tanzania, using gut content analysis and stable isotope analysis of carbon and
nitrogen. Gut content analysis revealed that within fish species almost the same food items were
consumed regardless of the different habitats in which they were caught. Crustaceans (mainly
copepods, crabs and shrimps) were the preferred food for most zoobenthivores and omnivores,
while fishes and algae were the preferred food for piscivores and herbivores, respectively. The mean
d13C values of fishes and food items from the mangrove habitats were significantly depleted to
those from the seagrass habitats by 6 9 and 9 7% for fishes and food items, respectively, and to
those from the mud and sand flats by 3 5 and 5 8%, respectively. Fishes and food items from the
mud and sand flats were significantly depleted as compared to those of the seagrass habitats by 3 4
and 3 9%, for fishes and food, respectively. Similar to other studies done in different geographical
locations, the importance of mangrove and seagrass themselves as a primary source of carbon to
higher trophic levels is limited. The different bay habitats were all used as feeding grounds by
different fish species. Individuals of the species Gerres filamentosus, Gerres oyena, Lethrinus lentjan,
Lutjanus fulviflamma, Pelates quadrilineatus and Siganus sutor appeared to show a connectivity with
respect to feeding between different habitats by having d13C values which were in-between those of
food items from two neighbouring habitats. This connectivity could be a result of either daily tidal
migrations or recent ontogenetic migration. # 2006 The Authors
Journal compilation # 2006 The Fisheries Society of the British Isles
Description
Keywords
Feeding areas, Habitat connectivity, Juvenile fishes, Mangroves, Stable isotopes, Seagrass beds
Citation
Lugendo, B.R., Nagelkerken, I., Van Der Velde, G. and Mgaya, Y.D., 2006. The importance of mangroves, mud and sand flats, and seagrass beds as feeding areas for juvenile fishes in Chwaka Bay, Zanzibar: gut content and stable isotope analyses. Journal of Fish Biology, 69(6), pp.1639-1661.