The functional diversity of fish assemblages in the vicinity of oil and gas pipelines compared to nearby natural reef and soft sediment habitats

We would like to thank skippers John Totterdell and Kylie Skipper who assisted and made data collection possible. We acknowledge David Whillas and Kevin Holden who operated the stereo-ROV on the pipelines. The contributions of Laura Fullwood and Damon Driessen both in the field and with image analysis are gratefully acknowledged, as is Jack Park for his assistance with image analysis. This research project was funded by Chevron through its Anchor Partnership with the UK National Decommissioning Centre. We also acknowledge in-kind support from Net Zero Technology Centre and the University of Aberdeen through their partnership in the UK National Decommissioning Centre.Peer reviewedPublisher PD

Spawning aggregation of bigeye trevally, Caranx sexfasciatus, highlights the ecological importance of oil and gas platforms

Open Access via the Elsevier Agreement Acknowledgements We gratefully acknowledge the field and logistical support provided by the Crew of the Resolution. This research project was funded by Chevron through its Anchor Partnership with the UK National Decommissioning Centre. We also acknowledge in-kind support from Net Zero Technology Centre and the University of Aberdeen through their partnership in the UK National Decommissioning Centre.Peer reviewedPublisher PD

Nutrients increase epiphyte loads: broad-scale observations and an experimental assessment

The original publication can be found at www.springerlink.comThere is a global trend towards elevated nutrients in coastal waters, especially on human-dominated coasts. We assessed local- to regional-scale relationships between the abundance of epiphytic algae on kelp ( Ecklonia radiata) and nutrient concentrations across much of the temperate coast of Australia, thus assessing the spatial scales over which nutrients may affect benthic assemblages. We tested the hypotheses that (1) percentage cover of epiphytic algae would be greater in areas with higher water nutrient concentrations, and (2) that an experimental enhancement of nutrient concentrations on an oligotrophic coast, to match more eutrophic coasts, would cause an increase in percentage cover of epiphytic algae to match those in more nutrient rich waters. Percentage cover of epiphytes was most extensive around the coast of Sydney, the study location with the greatest concentration of coastal chlorophyll a (a proxy for water nutrient concentration). Elevation of nitrate concentrations at a South Australian location caused an increase in percentage cover of epiphytes that was comparable to percentage covers observed around Sydney’s coastline. This result was achieved despite our inability to match nutrient concentrations observed around Sydney (<5% of Sydney concentrations), suggesting that increases to nutrient concentrations may have disproportionately larger effects in oligotrophic waters.Bayden D. Russell, Travis S. Elsdon Bronwyn M. Gillanders and Sean D. Connel

Experimental evaluation of stable isotope fractionation in fish muscle and otoliths

Stable isotope analyses (SIA) of carbon and nitrogen are used routinely in food-web studies to determine diet and trophic position. We tested several common assumptions of SIA by rearing juvenile mummichog Fundulus heteroclitus on 5 isotopically distinct diets under controlled laboratory conditions. We determined the effect of diet type and lipid extraction on 13C and 15N fractionation between diet and muscle. We also examined fractionation of 13C between otolith and both diet and muscle. Both 13C and 15N were enriched from diet to fish muscle, but the degree of fractionation differed among diets. Carbon isotope fractionation from diet to fish muscle exceeded assumed values of <1‰ and ranged from 1.2 to 3.9‰, while nitrogen fractionation ranged from 2.7 to 7.8 ‰. Extracting lipids from fish muscle increased both 13C and 15N by approximately 1‰. Lipid extraction also increased variation in treatment means for 15N, but not 13C. Otoliths were enriched in 13C compared to both diet and fish muscle. Bulk otolith 13C values were strongly correlated with muscle tissue, and reflected the same total change in 13C observed among diet treatments. It was tempting to conclude that otoliths were accurately recording 13C values of the diet. However, more information is required on the effects of diet, metabolic rate, and 13C of ambient dissolved inorganic carbon on otolith 13C before these structures can be used to reconstruct diet histories of individual fish.T. S. Elsdon, S. Ayvazian, K. W. McMahon and S. R. Thorrol

The capacity of imaging sonar for quantifying the abundance, species richness, and size of reef fish assemblages

Funding Information: We acknowledge Kevin Holden from Deep Vision Subsea, Ben Saunders, Iain Parnum, and Damon Driessen for the collection of video and acoustic imagery used in the figures in this review. We thank Tony Scarangella for the provision and skippering of the research vessel in the collection of data from the Rottnest fish towers. We thank Se Songploy for assistance with imaging sonar deployments in Thailand. This research project was funded by Chevron through a research grant to Curtin University under the Western Australian Energy Research Alliance (AES 17-P2TD-151-A1) and its Anchor Partnership with the UK National Decommissioning Centre. We also acknowledge in-kind support from Net Zero Technology Centre and the University of Aberdeen through their partnership with the UK National Decommissioning Centre.Peer reviewedPublisher PD

Quantifying the ability of imaging sonar to identify fish species at a subtropical artificial reef

Imaging sonars (ISs) are high-frequency acoustic devices that are increasingly being used to study fish in marine and freshwater habitats. Acoustic devices are limited in quantifying species richness, and previous attempts to identify fish species using IS have mostly focused on assemblages of low species richness or high morphological diversity. This study aimed to determine the ability of IS for identifying fish species at a subtropical artificial reef off Perth, Western Australia. Several fish traits that could be defined using IS were identified and described for all fish species observed with simultaneous optical footage. These traits were used to create a clustering algorithm to infer the species identity of IS detections of the five most abundant species at the reef. The identities of all fish from two species (Chromis westaustralis and Neatypus obliquus) were inferred with 100% success, though no individuals from the remaining three species (Seriola dumerili, Coris auricularis, and Pempheris klunzingeri) were correctly identified. An alternative clustering-based approach to categorising fish detected by IS independent of taxonomic inference was also implemented. Overall, this study demonstrates that IS can identify reef fish with variable success, and proposes an alternative method for describing fish assemblages irrespective of species identity

Quantifying the ability of imaging sonar to identify fish species at a subtropical artificial reef

Imaging sonars (ISs) are high-frequency acoustic devices that are increasingly being used to study fish in marine and freshwater habitats. Acoustic devices are limited in quantifying species richness, and previous attempts to identify fish species using IS have mostly focused on assemblages of low species richness or high morphological diversity. This study aimed to determine the ability of IS for identifying fish species at a subtropical artificial reef off Perth, Western Australia. Several fish traits that could be defined using IS were identified and described for all fish species observed with simultaneous optical footage. These traits were used to create a clustering algorithm to infer the species identity of IS detections of the five most abundant species at the reef. The identities of all fish from two species (Chromis westaustralis and Neatypus obliquus) were inferred with 100% success, though no individuals from the remaining three species (Seriola dumerili, Coris auricularis, and Pempheris klunzingeri) were correctly identified. An alternative clustering-based approach to categorising fish detected by IS independent of taxonomic inference was also implemented. Overall, this study demonstrates that IS can identify reef fish with variable success, and proposes an alternative method for describing fish assemblages irrespective of species identity

An acoustic-optic comparison of fish assemblages at a Rigs-to-Reefs habitat and coral reef in the Gulf of Thailand

Open Access via the Elsevier agreement. This research project was funded by Chevron through a research grant to Curtin University under the Western Australian Energy Research Alliance (AES 17-P2TD-151-A1) and its Anchor Partnership with the UK National Decommissioning Centre. We also acknowledge in-kind support from Net Zero Technology Centre and the University of Aberdeen through their partnership with the UK National Decommissioning Centre.Peer reviewedPublisher PD

Sound sees more:A comparison of imaging sonars and optical cameras for estimating fish densities at artificial reefs

Funding Information: This research project was funded by Chevron through a research grant to Curtin University under the Western Australian Energy Research Alliance ( AES 17-P2TD-151-A1 ) and its Anchor Partnership with the UK National Decommissioning Centre . We also acknowledge in-kind support from Net Zero Technology Centre and the University of Aberdeen through their partnership with the UK National Decommissioning Centre . Publisher Copyright: © 2023 The AuthorsPeer reviewedPublisher PD