Seagrass Importance in Food Provisioning Services: Fish Stomach Content as a Link between Seagrass Meadows and Local Fisheries

Abstract

Abstract-The links between ecosystem processes and functions and ecosystem services (i.e. the human benefits from those) are elusive. In this paper, the food provisioning service of seagrass meadows is operationalized through the study of the stomach contents of 13 important commercial fish species in Chwaka Bay, Zanzibar. Using local fishers' knowledge on bait, scientific knowledge about the structure of the meadows (associated flora and fauna), stomach content analysis and multivariate statistics, the food provisioning service associated with seagrasses and its importance for fish (as important diet component) and for humans (in small-scale artisanal fisheries) are described. The study presents the food items for 13 commercial fish species identified at the lowest possible taxonomical level and compares with previous literature findings. In addition, differences in stomach contents of Siganus sutor and Leptoscarus vaigiensis caught with both drag-nets and dema basket traps are investigated in order to explore bait presence and indirectly evaluate fishers' knowledge on bait preference. The results show that most of the items consumed by commercial fishes are associated with seagrass beds and that there are clear indicators that the bait traditionally used seems to be effective. The paper elaborates on the consideration of seagrass ecosystems in a holistic perspective, the difficulties in valuation of ecosystem services and finally the crucial importance of these aspects for human well-being and sustainability in coastal communities of the Western Indian Ocean.

Seascape Configuration Leads to Spatially Uneven Delivery of Parrotfish Herbivory across a Western Indian Ocean Seascape

“…The most common parrotfishes in the seagrass meadows in the Bazaruto Archipelago are L. vaigiensis and juvenile S. ghobban [70]. These two species are widespread in coastal areas throughout the region and are frequently targeted in the artisanal fishery [59,65,[71][72][73]. However, there is limited knowledge of feeding behaviour by L. vaigiensis (but see [69,71,74]) and S. ghobban in the WIO.…”

“…These two species are widespread in coastal areas throughout the region and are frequently targeted in the artisanal fishery [59,65,[71][72][73]. However, there is limited knowledge of feeding behaviour by L. vaigiensis (but see [69,71,74]) and S. ghobban in the WIO. Furthermore, little is known about how grazing patterns of S. ghobban are related to ontogenetic habitat shifts.…”

Hierarchical scales of spatial variation in the smaller surface and near-surface macrobenthos of a subtropical intertidal seagrass system in Moreton Bay, Queensland

“…Bouchet et al, 2002;Jaschinski & Sommer, 2008;Barnes, 2010a), notwithstanding that these species provide the food source for the juveniles of a wide range of commercially important fish and crustaceans (Jackson et al, 2001;de la Torre-Castro et al, 2008;Vizzini, 2009). Most work on this faunal size category in shallow marine systems has been devoted to the micromolluscan fauna of coralline algal turfs on rocky shores, amongst which marked patchiness in time and space appears typical (e.g.…”

The trophic structure of fish in seaweed farms, and adjacent seagrass and coral habitats in Zanzibar, Tanzania

“…There is little information on trophic regimes of fish in seagrass and coral reefs in the Western Indian Ocean (WIO) region (de Troch et al, 1998;Almeida et al, 2001;de Boer et al, 2001;de la Torre-Castro et al, 2008). Foraging fish that migrate daily are known to move between a few hundred meters to a few kilometers, often between coral reefs and seagrass beds (Nagelkerken et al, 2000;Berkstrom et al, 2013), yet information on trophic interactions and movements of fish between seaweed farms, seagrass and coral reefs is scarce and variation in fish diet specialization has not yet been well reported (de Carvalho et al, 2015).…”