Preliminary estimates of the abundance and fidelity of dolphins associating with a demersal trawl fishery

The incidental capture of wildlife in fishing gear presents a global conservation challenge. As a baseline to inform assessments of the impact of bycatch on bottlenose dolphins (Tursiops truncatus) interacting with an Australian trawl fishery, we conducted an aerial survey to estimate dolphin abundance across the fishery. Concurrently, we carried out boat-based dolphin photo-identification to assess short-term fidelity to foraging around trawlers, and used photographic and genetic data to infer longer-term fidelity to the fishery. We estimated abundance at approximate to 2,300 dolphins (95% CI = 1,247-4,214) over the ≈ 25,880-km2 fishery. Mark-recapture estimates yielded 226 (SE = 38.5) dolphins associating with one trawler and some individuals photographed up to seven times over 12 capture periods. Moreover, photographic and genetic re-sampling over three years confirmed that some individuals show longterm fidelity to trawler-associated foraging. Our study presents the first abundance estimate for any Australian pelagic dolphin community and documents individuals associating with trawlers over days, months and years. Without trend data or correction factors for dolphin availability, the impact of bycatch on this dolphin population's conservation status remains unknown. These results should be taken into account by management agencies assessing the impact of fisheries-related mortality on this protected species.Publisher PDFPeer reviewe

Land use changes and the properties of stormwater entering a wetland on a sandy coastal plain in Western Australia

This study investigated the catchment of an urban wetland on sandy soils in Perth, Western Australia. The wetland is of high conservation value but is currently used as a stormwater-compensating basin. The three main aims of this work were to: 1. determine the importance of stormwater drains in the water and pollutant balance of the lake; 2. evaluate pollutant retention rates by the wetland; and 3. identify current land uses in the catchment, determine their impacts on the wetland and identify tolerable levels of urbanisation for a wetland of this type. Stormwater flowing in and out of the lake subcatchments was monitored for two years for background flows and storm events. Water discharge, physical and chemical characteristics - including nutrients and heavy metals - were measured. Water and pollutant mass balances were determined. There was year-round flow at all sites, except from the smallest subcatchment. Flow characteristics differed between sites and were more influenced by catchment characteristics than rain intensity or duration. More water entered than left the lake in spring. In autumn more water left the lake via the overflow than entered. Due to poor maintenance, many drains overflowed during storm events. When compared to Australian and New Zealand Environment and Conservation Council (ANZECC) water quality guidelines for receiving waters, only pH and conductivity met the recommended criteria. The nutrient and heavy metal loads varied with rainfall during both years of study. Suspended solids, total nitrogen and total phosphorus concentrations were proportional to rainfall, while concentrations of dissolved forms of nutrients were not. Background flows contributed significantly to the pollutant load. More than 85% of total suspended solids, nutrients and heavy metals were retained by the wetland - the only exceptions being copper and some forms of dissolved nutrients. An evaluation of the performance of the lake as a pollutant sink, using published data from constructed wetlands, identified phosphorus as the pollutant that requires the largest area for treatment

Bathymetry Derivatives and Habitat Data from Hyperspectral Imagery Establish a High-Resolution Baseline for Managing the Ningaloo Reef, Western Australia

The Ningaloo Reef, Australia’s longest fringing reef, is uniquely positioned in the NW region of the continent, with clear, oligotrophic waters, relatively low human impacts, and a high level of protection through the World Heritage Site and its marine park status. Non-invasive optical sensors, which seamlessly derive bathymetry and bottom reflectance, are ideally suited for mapping and monitoring shallow reefs such as Ningaloo. Using an existing airborne hyperspectral survey, we developed a new, geomorphic layer for the reef for depths down to 20 m, through an object-oriented classification that combines topography and benthic cover. We demonstrate the classification approach using three focus areas in the northern region of the Muiron Islands, the central part around Point Maud, and Gnaraloo Bay in the south. Topographic mapping combined aspect, slope, and depth into 18 classes and, unsurprisingly, allocated much of the area into shallow, flat lagoons, and highlighted narrow, deeper channels that facilitate water circulation. There were five distinct geomorphic classes of coral-algal mosaics in different topographic settings. Our classifications provide a useful baseline for stratifying ecological field surveys, designing monitoring programmes, and assessing reef resilience from current and future threats

Cultural ecosystem values of the Kimberley coastline: an empirical analysis with implications for coastal and marine policy

Cultural ecosystem services have received increasing attention in land/marine use planning but remain poorly known, expressed, and utilised in planning processes. Progress in marine spatial planning requires better information regarding the full range of values and benefits received from ecosystem services, including cultural ecosystem values. This paper reports on an online Public Participation GIS (PPGIS) study that collected spatially explicit information on cultural ecosystem values in the remote Kimberley coastal region in northwestern Australia. The coastal zone – 20 km landwards and seawards – was found to be highly valued with values disproportionally located 0–2 km onshore. The number of value markers placed was related to tenure, access (i.e., density of tracks), population density, and geomorphology. Methodologically, Public Participation GIS describes the location and extent of values providing for the exploration of relationships between values and other planning features such as tenure and coastal access. Inclusion of such information in marine spatial planning and policy formulation can contribute to more thoughtful and inclusive decisions regarding the future of coastal zones. The use of internet-based Public Participation GIS is particularly useful for long, remote coastlines with widely dispersed stakeholder interests where other methods such as interviews and workshops are not feasible

Summary of areas and percentage components of the main cover types mapped in the four regions at Ningaloo Reef.

<p>Summary of areas and percentage components of the main cover types mapped in the four regions at Ningaloo Reef.</p

Example of benthic habitats for the Turquoise Bay area of Ningaloo Reef at the thematic classification level 4a.

<p><b>Legend codes explained in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0070105#pone-0070105-t001" target="_blank"><b>Table 1</b></a><b>.</b></b></p

Overview of the northern region of the Ningaloo Reef with insets illustrating selected habitat maps and corresponding subsurface reflectance.

<p>(Ar) Subsurface reflectance of nearshore, sublittoral pavement along a rocky shore, (A) habitats of extensive macro-algae, limestone pavement and sand. (Br) Subsurface reflectance of outer reef flat, (B) spur and groove structures with coral and macro-algae transitioning to tabulate coral and sand in the deeper lagoon. (Cr) Subsurface reflectance of the littoral alluvial fan off Yardie Creek, (C) habitats with limestone pavement and adjacent macro-algae with sparse coral. (Dr) Subsurface reflectance of the back reef, (D) back reef on the northern edge of the reef pass with clusters of bommies south and east of the reef flats. Legend from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0070105#pone-0070105-g005" target="_blank">Figure 5</a> applies.</p

Extent of the HyMap survey area and location of the field sites and key locations at Ningaloo Reef.

<p>Outlines of the state and Commonwealth marine park boundaries are also indicated.</p

PCA transformed data from image-derived spectra viewed in a two-dimensional space showing continuous (>90% cover) coral classes as well as the tabulate/digitate cluster from Ningaloo Reef.

<p>Axes created through the PCA process removed correlations evident in untransformed spectra and allowed identification of outliers, trends and groups.</p

Summary of the labelling approach for benthic components at Ningaloo Reef using class label and percentage cover.

<p>Summary of the labelling approach for benthic components at Ningaloo Reef using class label and percentage cover.</p