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Monitoring of environmental impacts of mining activities typically focuses on the main operation footprint, neglecting exploration infrastructure like tracks, roads, and drill pads. These areas are cleared of native vegetation and impacts on the surrounding environment can be both cumulative and enigmatic. Here, we study the impacts of mining exploration infrastructure on habitat characteristics and ground-dwelling arthropod communities in the Midwest region of Western Australia. The study was conducted at three mine sites, each with three infrastructure types: maintained tracks, unmaintained tracks, and drill pads along transects extending 100 m away from the disturbance into remnant vegetation. Habitat characteristics were measured, and arthropods collected from pitfall traps along these transects and identified using COI metabarcoding. The overall arthropod community and two indicator groups, ants (Formicidae) and springtails (Collembola) - were used to measure arthropod responses to changes in response to habitat disturbance. Whilst changes in habitat were only visible to 10 m from the disturbance, impacts on arthropod communities could be detected up to 100 m into the remnant vegetation, and these responses were more complex. In general, we found similar patterns expressed in the compositional changes for arthropods overall and between our chosen indicator groups, but they were not the same across all sites and infrastructure types. Our results demonstrate the utility of bulk arthropod metabarcoding and different arthropod indicator groups for documenting the effects of fine-scale habitat destruction, degradation, or disturbance. They also highlight the need to monitor the negative impacts of mineral exploration on the environment. [ABSTRACT FROM AUTHOR]

Aim: Compare the distribution and composition of temperate Labridae (wrasse) assemblages on shallow water coastal reefs in South‐Western Australia between 2006 and 2015, after a decade characterized by both gradual ocean warming and severe heatwave events. Location: South‐Western Australia from Port Gregory to the Recherché Archipelago. Methods: Surveys of Labridae fishes were conducted in 2006 and repeated in 2015 across 112 reefs spanning 2,000 km of coastline, using diver‐operated stereo‐video systems (stereo‐DOVs). We used a hierarchical design with seven regions, four locations in each region, four reef sites in each location and twelve transects in each site. Results: In 2015, we found an increase in abundance of tropical and subtropical labrid species that were rarely observed in 2006. Three temperate species declined in abundance, which tended to be large and slow growing fish. Twenty‐two labrid species increased in abundance. There was also a discernible poleward shift in 20 of the 25 most abundant and representative labrid species from 2006 to 2015. The labrid community composition was explained predominantly by sea surface temperature (SST), physical reef structure and kelp (Ecklonia radiata) cover. Main conclusions: Our study reveals that labrid assemblages associated with the shallow water temperate reefs of South‐Western Australia have undergone rapid changes across almost 2,000 km of coastline, with warm‐temperate waters showing the strongest change. However, cool‐temperate waters on the south coast also showed significant changes in the composition of the labrid assemblages. Our findings provide important insights into the effects of warming and habitat loss on warm‐temperate assemblages and the potential trajectory of change for cool‐temperate assemblages under a warmer future. [ABSTRACT FROM AUTHOR]

Abstract Fish communities are an important cultural, recreational and commercial resource that also have an important role in the functioning of marine ecosystems. Around the world fish assemblages are experiencing pressures from anthropogenic activities, and marine spatial planning is being established to mitigate these impacts and assist with biodiversity conservation. Information about how fish assemblages are structured across a range of spatial scales which encompass variations in physical, biotic and environmental parameters will assist marine spatial planning and management. We investigated differences in reef fish assemblage composition over three reef lines across an inshore to offshore gradient (3–23 m depth) at two marine reserves (70 km apart) in the Perth metropolitan region, Western Australia. There were significant increases in the number of individuals, species richness, and relative abundance of fish species across the shallow shelf depth gradient in the two locations. There were distinct fish assemblages associated with each reef line, correlated to depth and distance from shore. The differences across the shelf gradient, even over this small depth range, were greater than the differences between the two locations. These findings have implications for marine spatial management and the design of marine reserves that aim to conserve biodiversity. It may be most appropriate for such marine reserves to encompass a wide depth gradient, rather than a large longshore area. At the very least, cross and longshore patterns in fish assemblages should be taken into consideration and used to guide spatial management plans for biodiversity conservation. Highlights • Differences in fish assemblages were found across a shallow reef line depth gradient. • Species richness and abundance increased from inshore to offshore reefs. • Patterns in composition among reef lines were consistent among locations. • Among reef line differences were greater than differences between locations. • Marine reserves should encompass cross-shore variation for biodiversity conservation. [ABSTRACT FROM AUTHOR]

Cumulative anthropogenic impacts such as overfishing, and climate change are placing marine ecosystems under increasing pressure. This includes the loss or degradation of marine habitats and reductions in fish stocks, with conservation and fisheries management strategies aiming to mitigate, or reverse the effects. Measuring the effectiveness of management actions on fish requires accurate data on the abundance and size of fishes. Diver operated stereo-video systems (stereo-DOVs) have become a widely accepted method for surveying reef fish but have known biases and constraints. A new generation of small and affordable remotely operated vehicles (ROVs) can carry a stereo-video system to collect reef fish data without the need for divers. However, before ROVs are adopted there is a need to understand how they compare to other conventional survey methods. We compared how stereo-DOVs and stereo-ROVs influenced fish behaviour and sampled coral reef fish assemblages inside and outside sanctuary zones in the Ningaloo Marine Park, Northern Western Australia. In general, the numbers of species, individuals and the assemblage composition did not differ significantly between survey techniques and detected consistent patterns in the assemblage composition across locations and inside and outside sanctuary zones. Both methods recorded similar proportions of length measurements (68% and 70% for stereo-DOV and stereo-ROV respectively). Fishes were significantly more wary and exhibited more flight responses towards stereo-DOVs when compared to stereo-ROVs. The use of ROVs has the potential to be a cost-effective method of surveying reef fish while eliminating the health and safety risks involved with SCUBA diving. Given the comparable metrics as well as reduced behavioural bias and logistical advantages of using stereo-ROVs, we recommend stereo-ROVs as a viable alternative to stereo-DOVs surveys. • Fish assemblage composition sampled Stereo-DOVs and stereo-ROV was similar. • Both techniques record similar numbers of species and fish individual. • Fish allowed the Stereo-ROVs to approach them closer than stereo-DOVs. • Stereo-ROV is a cost-effective alternative to stereo-DOVs. • Stereo-ROV can operate deeper, with less health and safety risks then stereo-DOVS. [ABSTRACT FROM AUTHOR]

Spatially explicit information on coral fish species abundance and distribution is required for effective management. Nonextractive techniques, including echosounders and video census, can be particularly useful in marine reserves where the use of extractive methods is restricted. This study aimed to investigate the possibility of combining echosounders and baited remote underwater stereo-videos (stereo-BRUVs) in providing more holistic information on the distribution of demersal and semidemersal reef-associated fish. The spatial distribution of fish biomass was assessed using both methods in two small areas, one in Cockburn Sound (CS), a temperate body of water, and the other in the tropical waters of the Ningaloo Marine Park (NMP). The results showed high correlations between the acoustic and stereo-BRUV data in CS, suggesting the potential use of both for a better estimation of biomass in the area. The results for the NMP showed weaker correlations between the two datasets and highlighted the high variability of the system. Further studies are required, but our initial findings suggest a potential benefit of combining both techniques in the reef-associated fish distribution assessment. [ABSTRACT FROM AUTHOR]

Many marine fish populations have declined due to the individual or cumulative impacts of increasing water temperatures, ocean acidification, overfishing and other human-induced impacts such as land run-off, dredging and habitat alteration. Some solutions may be offered by ecosystem-based fisheries and conservation management. However, understanding their effectiveness relies on the availability of good quality data on the size distributions and abundance of fish populations and assemblages, collected at appropriate temporal and spatial scales. Since the early 2000s, baited remote underwater video systems (BRUVs) have become a popular tool for collecting data on fish assemblages across a range of depths and habitats. In Australia, this technique has been adopted by many different agencies and institutions, creating a unique opportunity to compile a continental-scale synthesis of fish data using a standardised sampling technique. Key Australian researchers and managers were invited to contribute to a synthesis workshop on baited underwater video in Albany, Western Australia between the 4th and 8th of February 2018. Data from 19,939 BRUVs deployments, collected between 2000 and 2017 around Australia, were compiled using GlobalArchive (globalarchive.org). The workshop identified and prioritised several key research themes that would contribute to the conservation and sustainable management of focal species and broad assemblages. Our goal is to describe where and when the data were collected, the type of equipment used and how the imagery was analysed. We also discuss the types of questions that can be addressed by analysing these standardised datasets and the potential benefits to conservation and fisheries management. [ABSTRACT FROM AUTHOR]

The cryptic external morphology of fishes poses challenges for accurate species identification. This study assessed whether the morphometry of otoliths (and body length) could be used as a method to distinguish among closely related, morphologically similar species that are highly valued by commercial or recreational fishers. The otolith morphometry of fishes within four genera (Centroberyx , Lethrinus , Polyprion and Sillago) were compared. Canonical Analysis of Principal Coordinates that included combinations of morphometric variables (i.e., otolith length, width, thickness, weight, and fish length) produced highly accurate species prediction rates ranging from 92.5 to 99.9% across all genera. When different combinations of morphometric variables were modelled, changes in species prediction accuracy rates were minimal (i.e., up to 3%) for the Centroberyx , Polyprion and Sillago species. The exclusion of otolith weight from the multivariate analysis did not significantly decrease prediction accuracy within all four genera. In contrast, the prediction accuracy of the two lethrinids reduced by 7–25% when fish length was excluded, which may be attributable to the larger size attained by L. nebulosus in comparison to its congener L. punctulatus , as well as the very similar ovate shaped otoliths in younger fish of both species. Simplifying data collection to only length-based otolith measurements (and fish length for lethrinids) would provide a more rapid and cost-effective method for discrimination and be more practical when sampling at sea where obtaining accurate weight measurements of otoliths is typically unfeasible. Spatial variation in otolith morphometrics was evident for C. gerrardi , L. punctulatus , P. oxygeneios and S. vittata , which might be attributed to the differences in length distributions of fish samples from different regions. The misclassified specimens within the species groups were notably smaller individuals, suggesting the complexity of otolith shape increases with ontogeny. Hence, further investigation of variations in morphological characteristics, other than otoliths, may be required for the discrimination of cryptic species during the juvenile stage. This study highlights the robustness of multivariate analysis of otolith morphometric data for discriminating closely-related, cryptic species. • Otolith morphometric analyses discriminate cryptic teleosts within four genera. • Species prediction accuracy rates range from 92.5 to 99.9%. • Otolith morphometric models are a rapid, cost-effective species discrimination tool. [ABSTRACT FROM AUTHOR]

Monitoring programs that aim to measure the diversity, abundance and biomass of fishes depend on accurate and reliable biological data to guide the development of robust management plans. It is important to implement an appropriate sampling technique that provides a comprehensive assessment, while reducing associated biases in the data collection process. We compared the sampling abilities of four different underwater stereo-video techniques; baited remote underwater stereo-video systems (BRUV), diver operated stereo-video (DOV), and two relatively new methodologies; slow towed stereo-video (STV) and remotely operated vehicle (ROV) fitted with a stereo-video. Comparisons were conducted in a temperate reef system along a single limestone ridge within Geographe Bay, Western Australia. More fish species and individuals were sampled by BRUVs, while transect based methods (DOV, STV, and ROV) were comparable. Combining BRUVs with a transect method resulted in a ~10% increase in observed diversity. BRUVs had a higher statistical power to detect change in comparison to the transect methods. This was due to the higher variability observed in transect methods that may sample greater habitat heterogeneity within a sample unit compared to BRUVs. Although differences did exist, data collected with the ROV was generally comparable to the other transect methods. We believe further research into ROV use is warranted as they provide a safer alternative to diver-based techniques and have the ability to extend into deeper-waters. We recommend that for fish diversity and abundance assessments a sampling strategy that combines BRUVs and a transect method should be adopted. • BRUVs sampled more fish and species compared to transect methods which were similar. • Using BRUVs with a transect based method increased observed diversity by ~10%. • BRUVs had the greatest statistical power to detect changes in fish assemblages. • Transects sample within habitat heterogeneity and ROV provides a safety advantage. [ABSTRACT FROM AUTHOR]

Offshore decommissioning activities are expected to increase as oil and gas subsea infrastructure becomes obsolete. Decisions on decommissioning alternatives will benefit from quantifying and understanding the marine communities associated with these structures. As a case study, fish assemblages associated with an inshore network of subsea pipelines located on the North West shelf of Western Australia were compared to those in surrounding natural reef and soft sediment habitats using remotely operated vehicles fitted with a stereo-video system (stereo-ROVs). The number of species, the abundance, biomass, feeding guild composition and the economic value of fishes were compared among habitats. The community composition of fish associated with pipelines was distinct from those associated with natural habitats, and was characterised by a greater abundance and/or biomass of fish from higher trophic levels (e.g. piscivores, generalist carnivores and invertivores), including many species considered to be of value to commercial and recreational fishers. Biomass of fish on pipelines was, on average, 20 times greater than soft sediments, and was similar to natural reefs. However, the biomass of species considered important to fisheries recorded on the pipelines was, on average 3.5 times greater than reef and 44.5 times greater than soft sediment habitats. This study demonstrates that fish assemblages on the pipeline infrastructure exhibit high ecological and socioeconomic values.

Marine ecosystems are changing rapidly as the oceans warm and become more acidic. The physical factors and the changes to ocean chemistry that they drive can all be measured with great precision. Changes in the biological composition of communities in different ocean regions are far more challenging to measure because most biological monitoring methods focus on a limited taxonomic or size range. Environmental DNA (eDNA) analysis has the potential to solve this problem in biological oceanography, as it is capable of identifying a huge phylogenetic range of organisms to species level. Here we develop and apply a novel multi-gene molecular toolkit to eDNA isolated from bulk plankton samples collected over a five-year period from a single site. This temporal scale and level of detail is unprecedented in eDNA studies. We identified consistent seasonal assemblages of zooplankton species, which demonstrates the ability of our toolkit to audit community composition. We were also able to detect clear departures from the regular seasonal patterns that occurred during an extreme marine heatwave. The integration of eDNA analyses with existing biotic and abiotic surveys delivers a powerful new long-term approach to monitoring the health of our world's oceans in the context of a rapidly changing climate., Competing Interests: The Authors declare that no competing interests exists.

Niche requirements and habitat resource partitioning by conspecific fishes of different sizes are significant knowledge gaps in the species distribution modelling domain. Management actions and operations are typically concentrated on static habitats, or specific areas of interest, without considering movement patterns of species associated with ontogenetic shifts in habitat usage. Generalized additive models were used to model the body-length-habitat relationships of six fish species. These models were used to identify subsets of environmental parameters that drive and explain the continuous length-habitat relationships for each of the study species, which vary in their degree of ecological and/or commercial importance. Continuous predictive maps of the length distributions for each of the six study species across approximately 200 km 2 of the study area were created from these models. The spatial patterns in habitat partitioning by individuals of different body lengths for all six study species provide strong evidence for ontogenetic shifts. This highlights the importance of considering ontogenetic processes for marine spatial management. Importantly, predictive hotspot maps were created that identify potential areas that accumulate individuals of similar life stages of multiple species (e.g., multispecies nursery areas). In circumstances where limited resources are available for monitoring and management of fish resources, predictive modelling is a valuable tool for studying previously overlooked processes such as ontogenetic habitat shifts. Predictive modelling provides crucial information that elucidates spatial patterns in community composition across mosaics of benthic habitats. This novel technique can contribute to the spatial management of coastal fish and fisheries by identifying areas that are important for different life history stages of multiple fish species., (© 2017 by the Ecological Society of America.)