Waltham, Nathan J., Bradley, Michael, Wilson, Saara, Kane, Kevin, Langham, Odette, and Sheaves, Marcus (2022) Remotely operated vehicle reveals fish orientate to the substrate underneath marina floating pontoons. Estuarine, Coastal and Shelf Science, 280. 108184.

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Abstract

The modern day seascape is a mix of natural habitats (saltmarsh, mangroves, seagrass, unvegetated beaches), but increasingly is being replaced with hard engineering structures (e.g. floating pontoons) that have resulted in novel habitats available for flora and fauna. While these engineered structures provide new marine habitat resources, from the viewpoint of biodiversity, they effectively support a sub-set of species found in natural habitats. Unlike previous studies that have used divers for fish visual census, we used a remotely operated vessel with an underwater camera to examine the fish community using floating pontoons in a marina facility in tropical central Queensland, Australia. The camera filmed continuously the edge and underside of pontoons (both surveys covered silar pontoon linear distances– July (winter) 430m; November (summer) 485m; 2021). Fifteen fish species representing 14 families were recorded, with more species observed during summer compared to the wier survey. Remarkably, across both surveys of the 243 fishes individuals that were recorded, 16 6 (68%) appeared upside-down in videos (i.e., oriented to the underside of the pontoon). Engaging a behaviour of swimming upside-down has been acknowledged in natural habitats elsewhere; some coral reef species living in caves or reef ledges orientate themselves to the cave ceiling or overhanging ledge to increase prey capture rate. However, this is the first study to record fishes exhibiting the same behaviour. We conclude that our less invasive video survey approach provided the opportunity to observe fishes in a state of natural behaviour, orientating themselves towards the pontoon substrate, which is probably simply a response of adhering to basic characteristic modes, i.e., it is the orientation relative to the substrate that is important, rather than their orientation in space per se. Indeed marina pontoons provide an additional feature in already habitat complex estuaries; these data add to why we need to consider the ecosystem services offered by marine infrastructure, and the plasticity offish to adapt to new environments in an expanding blue economy.

Item ID:	77124
Item Type:	Article (Research - C1)
ISSN:	1096-0015
Keywords:	Fish, Underwater video, Estuaries, ROV, Ecological engineering, Blue economy
Copyright Information:	© 2022 Elsevier Ltd. All rights reserved.
Date Deposited:	25 Jan 2023 04:29
FoR Codes:	41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410401 Conservation and biodiversity @ 30% 41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410404 Environmental management @ 30% 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 40%
SEO Codes:	18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180203 Coastal or estuarine biodiversity @ 50% 18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180507 Rehabilitation or conservation of marine environments @ 50%
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