C. Roland Pitcher

C. Roland Pitcher
The Commonwealth Scientific and Industrial Research Organisation | CSIRO · Oceans and Atmosphere

About

127
Publications
47,460
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4,662
Citations

Publications

Publications (127)
Article
Full-text available
Bottom trawling is widespread globally and impacts seabed habitats. However, risks from trawling remain unquantified at large scales in most regions. We address these issues by synthesizing evidence on the impacts of different trawl-gear types, seabed recovery rates, and spatial distributions of trawling intensity in a quantitative indicator of bio...
Article
Full-text available
Vulnerable marine ecosystems (VMEs) are typically fragile and slow to recover, making them likely to be substantially altered by disturbance. In the High Seas, regional fishery management organizations (RFMOs) are required to implement measures to prevent significant adverse impacts on VMEs. The objectives of the present study were to: update distr...
Article
Full-text available
The Great Barrier Reef World Heritage Area in Queensland, Australia contains globally significant seagrasses supporting key ecosystem services, including habitat and food for threatened populations of dugong and turtle. We compiled 35 years of data in a spatial database, including 81,387 data points with georeferenced seagrass and species presence/...
Article
Full-text available
Building trust in science and evidence-based decision-making depends heavily on the credibility of studies and their findings. Researchers employ many different study designs that vary in their risk of bias to evaluate the true effect of interventions or impacts. Here, we empirically quantify, on a large scale, the prevalence of different study des...
Article
Bottom trawl fishing is a controversial activity. It yields about a quarter of the world's wild seafood, but also has impacts on the marine environment. Recent advances have quantified and improved understanding of large‐scale impacts of trawling on the seabed. However, such information needs to be coupled with distributions of benthic invertebrate...
Article
Trawl fishing constitutes an important part of the marine fisheries sector in Southeast Asia. It provides livelihoods and food for millions of people in coastal communities as well as feed for the region’s growing aquaculture sector. Trawl fisheries suffer from a multitude of problems, including overcapacity, excessive fishing effort, poor profitab...
Article
Protection of vulnerable marine ecosystems (VME) is a critical goal for marine conservation. Yet, in many deep-sea settings, where quantitative data are typically sparse, it is challenging to correctly identify the location and size of VMEs. Here we assess the sensitivity of a method to identify coral reef VMEs based on bottom cover and abundance o...
Article
Full-text available
Bottom‐trawl fisheries are the most‐widespread source of anthropogenic physical disturbance to seabed habitats. Development of fisheries‐, conservation‐ and ecosystem‐based management strategies requires the selection of indicators of the impact of bottom trawling on the state of benthic biota. Many indicators have been proposed, but no rigorous te...
Preprint
Full-text available
Bottom trawling accounts for almost one quarter of global fish landings but may also have significant and unwanted impacts on seabed habitats and biota. Management measures and voluntary industry actions can reduce these impacts, helping to meet sustainability objectives for fisheries, conservation and environmental management. These include change...
Article
Full-text available
Bottom trawlers land around 19 million tons of fish and invertebrates annually, almost one-quarter of wild marine landings. The extent of bottom trawling footprint (seabed area trawled at least once in a specified region and time period) is often contested but poorly described. We quantify footprints using high-resolution satellite vessel monitorin...
Article
Full-text available
1.Bottom trawling is the most widespread human activity directly affecting seabed habitats. Assessment and effective management of the effects of bottom trawling at the scale of fisheries requires an understanding of differences in sensitivity of biota to trawling. Responses to disturbance are expected to depend on the intrinsic rate of increase of...
Article
Kroodsma et al. (Reports, 23 February 2018, p. 904) mapped the global footprint of fisheries. Their estimates of footprint and resulting contrasts between the scale of fishing and agriculture are an artifact of the spatial scale of analysis. Reanalyses of their global (all vessels) and regional (trawling) data at higher resolution reduced footprint...
Article
Full-text available
Bottom-contact fishing gears are globally the most widespread anthropogenic sources of direct disturbance to the seabed and associated biota. Managing these fishing disturbances requires quantification of gear impacts on biota and the rate of recovery following disturbance. We undertook a systematic review and meta-analysis of 122 experiments on th...
Article
Full-text available
Trawling is the most widespread direct human disturbance on the seabed. Knowledge of the extent and consequences of this disturbance is limited because large-scale distributions of seabed fauna are not well known. We map faunal distributions in the Australian Exclusive Economic Zone (EEZ) and quantify the proportion of their abundance that occurs i...
Article
Full-text available
Bottom trawling is the most widespread human activity affecting seabed habitats. Here, we collate all available data for experimental and comparative studies of trawling impacts on whole communities of seabed macroinvertebrates on sedimentary habitats and develop widely applicable methods to estimate depletion and recovery rates of biota after traw...
Article
One of the objectives of the Applied Research Program (ARP), funded by Shell and the INPEX-operated Ichthys LNG Project, was to establish the basis for evaluating the effects of any potential oil spill from the Prelude or Ichthys fields on populations of commercially important demersal fishes in the Northern Demersal Scalefish Managed Fishery. The...
Article
Full-text available
Impacts of bottom fishing, particularly trawling and dredging, on seabed (benthic) habitats are commonly perceived to pose serious environmental risks. Quantitative ecological risk assessment can be used to evaluate actual risks and to help guide the choice of management measures needed to meet sustainability objectives. 2. We develop and apply a q...
Technical Report
Full-text available
The Pilbara shelf is an important area of ecological and development significance. Activities such as offshore gas and petroleum extraction and processing, major port developments, and commercial and recreational fishing occur together with primary natural resource conservation areas. Managers need information on habitats and biodiversity distribut...
Article
Full-text available
Management and technical approaches that achieve a sustainable level of fish production while at the same time minimizing or limiting the wider ecological effects caused through fishing gear contact with the seabed might be considered to be ‘best practice’. To identify future knowledge-needs that would help to support a transition towards the adopt...
Article
Full-text available
Models provide useful insights into conservation and resource management issues and solutions. Their use to date has highlighted conditions under which no-take marine protected areas (MPAs) may help us to achieve the goals of ecosystem-based management by reducing pressures, and where they might fail to achieve desired goals. For example, static re...
Article
Full-text available
Effects of trawling on sessile megabenthos in the Great Barrier Reef and evaluation of the efficacy of management strategies. A series of related research studies over 15 years assessed the effects of prawn trawling on sessile megabenthos in the Great Barrier Reef, to support management for sustainable use in the World Heritage Area. These large-sc...
Article
Biological sampling in marine systems is often limited, and the cost of acquiring new data is high. We sought to assess whether systematic reserves designed using abiotic domains adequately conserve a comprehensive range of species in a tropical marine inter-reef system. We based our assessment on data from the Great Barrier Reef, Australia. We des...
Article
Full-text available
Background Mobile bottom fishing, such as trawling and dredging, is the most widespread direct human impact on marine benthic systems. Knowledge of the impacts of different gear types on different habitats, the species most sensitive to impacts and the potential for habitats to recover are often needed to inform implementation of an ecosystem appro...
Article
Numerous studies have quantified trawl impacts at small scales. However, effective management of trawl impacts requires synthesis of experimental results (biomass depletion per tow and subsequent recovery) and application at fishery scales—realistically, this is achievable only in a modelling framework. We present a method for scaling up experiment...
Article
To support coastal planning through improved understanding of patterns of biotic and abiotic surrogacy at broad scales, we used gradient forest modeling (GFM) to analyze and predict spatial patterns of compositional turnover of demersal fishes, macroinvertebrates, and macroalgae on shallow, temperate Australian reefs. Predictive models were first d...
Article
Species richness and abundance are biodiversity metrics widely used to describe and estimate changes in biodiversity. Studies of marine species richness and abundance typically focus on one, or just a few, taxa. Consequently, it is currently not possible to understand the performance of predictors of species richness and abundance across marine tax...
Article
Understanding the drivers of broad-scale patterns of biodiversity is an overarching goal in ecology. We analysed environmental drivers of macroalgal species richness and composition on the continental shelf seabed of Australia’s Great Barrier Reef (GBR), and mapped these patterns to show phycologically diverse and depauperate areas. Although shelf...
Article
Indicators of trawl exposure were developed for 837 bycatch and benthos species, assemblages and habitats on the Great Barrier Reef shelf, by analysing their spatial distributions (mapped by a previous study) in relation to management zones, overlap with trawl grounds, and the intensity of trawl effort – and estimating the proportion of their distr...
Article
To examine whether benthic assemblages are more diverse in a region of high topographic and oceanographic complexity by comparing benthic invertebrate assemblages across continental margins with contrasting environments. Challenger Plateau and Chatham Rise, to the west and east of New Zealand, respectively. Benthic faunal data were sourced from ext...
Article
Surrogate taxa are used widely to represent attributes of other taxa for which data are sparse or absent. Because surveying and monitoring marine biodiversity is resource intensive, our understanding and management of marine systems will need to rely on the availability of effective surrogates. The ability of any marine taxon to adequately represen...
Conference Paper
Whole of ecosystem models that incorporate a broad range of physical, chemical and biological processes are well suited to exploring the dynamics of the complex issues related to multiple human uses in coastal regions, including cumulative effects. Over the last decade there has been strong growth in these kinds of models and they are now sufficien...
Article
Full-text available
1. Environmental variables are often used as indirect surrogates for mapping biodiversity because species survey data are scant at regional scales, especially in the marine realm. However, environmental variables are measured on arbitrary scales unlikely to have simple, direct relationships with biological patterns. Instead, biodiversity may respon...
Article
Full-text available
In ecological analyses of species and community distributions there is interest in the nature of their responses to environmental gradients and in identifying the most important environmental variables, which may be used for predicting patterns of biodiversity. Methods such as random forests already exist to assess predictor importance for individu...
Article
Full-text available
Understanding the capacity of species to acclimate and adapt to expected temperature increases is critical for making predictions about the biological impacts of global warming, yet it is one of the least certain aspects of climate change science. Tropical species are considered to be especially sensitive to climate change because they live close t...
Article
Full-text available
We analyzed and predicted spatial patterns of turnover in macroalgal community composition (beta diversity) that accounted for broad-scale environmental gradients using two contrasting community modelling methods, Generalised Dissimilarity Modelling (GDM) and Gradient Forest Modelling (GFM). Percentage cover data from underwater macroalgal surveys...
Data
Results obtained for the respondents of the online survey available at http://www.adelaide.edu.au/environment/mbp/survey/02.html. (DOC)
Data
Meta-data and references of literature reviewed. (DOC)
Data
WinBUGS code for Bayesian modelling. (DOC)
Article
Full-text available
The use of biological surrogates as proxies for biodiversity patterns is gaining popularity, particularly in marine systems where field surveys can be expensive and species richness high. Yet, uncertainty regarding their applicability remains because of inconsistency of definitions, a lack of standard methods for estimating effectiveness, and varia...
Article
Full-text available
We compare objectives and approaches of four regional studies of marine biodiversity: Gulf of Maine Area Census of Marine Life, Baltic Sea History of Marine Animal Populations, Great Barrier Reef Seabed Biodiversity Project, and Gulf of Mexico Biodiversity Project. Each program was designed as an "ecosystem" scale but was created independently and...
Data
Global seafloor abundance predictions. Predicted abundance (individual m-2) is in global 1×1 degree grids. Data fields include latitude, longitude, depth, and abundance of each size class. The abundance data are in logarithm scale (base 10). (CSV)
Data
Global seafloor biomass predictions. Predicted biomass (mg C m-2) is in global 1×1 degree grids. Data fields include latitude, longitude, depth, and biomass of each size class. The biomass data are in logarithm scale (base 10). (CSV)
Data
The complete list of references for the “CoML Fresh Biomass Database”. (DOC)
Data
Environmental predictors for Random Forest models. Data were logarithm transformed (base 10) and scaled to between 0 (minimum value) and 1 (maximum value). Detail description of the variable is given in Table 1. Abbreviations: mean = decadal or annual mean; sd = decadal or seasonal standard deviation. (TIFF)
Data
Distribution of mean biomass predictions for (a) bacteria, (b) meiofauna, (c) macrofauna, (d) megafauna, (e) invertebrates, and (f) fishes. The mean biomass was computed from 4 RF simulations. Predictions were smoothed by Inverse Distance Weighting interpolation to 0.1 degree resolution and displayed in logarithm scale (base of 10). (TIF)
Data
Google Earth file for the “CoML fresh biomass database”. (KML)
Data
Mean predictor Importance for abundance of (a) bacteria, (b) meiofauna, (c) macrofauna, and (d) megafauna. The mean ± S.D. (error bar) were calculated from 4 RF simulations. The top 20 most important variables are shown in descending order. Increase of mean square error (IncMSE) indicates the contribution to RF prediction accuracy for that variable...
Data
Coefficient of variation (C.V.) for mean abundance predictions of each size class. The C.V. was computed as S.D./mean * 100% from 4 RF simulations. The abbreviations are: bact = bacteria, meio = meiofauna, macro = macrofauna, mega = megafauna, inv = invertebrates, fis = fishes. (TIFF)
Data
Temporal coverage of primary productivity predictors between years of 1998 and 2007. Color ramp shows the sample size from 0 to 120 months of measurements. Detail description of the variable is given in Table 1. Abbreviations: n = sample size. (TIFF)
Data
Mean predictor Importance for biomass of (a) bacteria, (b) meiofauna, (c) macrofauna, and (d) megafauna. The mean ± S.D. (error bar) were calculated from 4 RF simulations. The top 20 most important variables are shown in descending order. Increase of mean square error (IncMSE) indicates the contribution to RF prediction accuracy for that variable....
Data
Distribution of mean abundance predictions for (a) bacteria, (b) meiofauna, (c) macrofauna, (d) megafauna, (e) invertebrates, and (f) fishes. The mean abundance was computed from 4 RF simulations. Predictions were smoothed by Inverse Distance Weighting interpolation to 0.1 degree resolution and displayed in logarithm scale (base of 10). (TIF)
Data
Coefficient of variation (C.V.) for mean biomass predictions of each size class. The C.V. was computed as S.D./mean * 100% from 4 RF simulations. The abbreviations are: bact = bacteria, meio = meiofauna, macro = macrofauna, mega = megafauna, inv = invertebrates, fis = fishes. (TIFF)