Influence of tides on assemblages and behaviour of fishes associated with shallow seagrass edges and bare sand

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 456:187-199 (2012) - DOI: https://doi.org/10.3354/meps09695 Influence of tides on assemblages and behaviour of fishes associated with shallow seagrass edges and bare sand Alistair Becker1,*, Christine Coppinger1,2, Alan K. Whitfield1 1South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa 2Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa *Email: a.becker@saiab.ac.za ABSTRACT: Seagrass beds and associated fish assemblages have been the focus of a large number of past studies. However, the influence of small water depth changes due to tides on fish species along shallow seagrass bed edges is unknown. In this study an underwater video camera was deployed to examine the fish community at 3 seagrass edge (Zostera capensis) and 3 sand sites over incoming spring and neap tides in the Bushmans Estuary, South Africa. Small changes in tidally driven water depth had significant effects on the abundance of common fish taxa, with gobies decreasing and others, including mullets, increasing in abundance. These general patterns were consistent in both seagrass and sand sites, as well as during spring and neap tidal cycles. There were inconsistent differences in the abundance of common fish taxa between seagrass edges and bare sand. Importantly, when differences did occur, these were contingent on tidal stage or linked to different tidal cycles (neap or spring), highlighting that small changes in depth may influence edge effects. The behaviour of fish did not appear to be influenced by water depth, but for some taxa there were distinct differences in swimming behaviour between those individuals associated with seagrass beds and those situated over bare sand. These small temporal scale changes in water depth are a previously overlooked aspect of littoral seagrass landscapes that may be important in structuring associated fish communities. KEY WORDS: Underwater video · Water depth · Estuary · Fish movements · Zostera capensis · South Africa Full text in pdf format PreviousNextCite this article as: Becker A, Coppinger C, Whitfield AK (2012) Influence of tides on assemblages and behaviour of fishes associated with shallow seagrass edges and bare sand. Mar Ecol Prog Ser 456:187-199. https://doi.org/10.3354/meps09695 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 456. Online publication date: June 07, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.