A summary of the Department of Fisheries, Western Australia invertebrate research at Cocos (Keeling) Islands 2006-2011

The Cocos (Keeling) Islands are located in the Indian Ocean (12° 12” S, 96° 54” E). The group is comprised of two separate coral atolls, consisting of 27 islands. The southern atoll consists of 26 islands, surrounding a shallow lagoon, two of which are inhabited with a total population of approximately 600 people. Management of the Cocos (Keeling) Islands’ fish resources is conducted by the Department of Fisheries Western Australia (DoF), on behalf of the Commonwealth Government, under a Service Delivery Agreement (SDA). Between 2006 and 2011 DoF has conducted annual risk assessments to focus research and management objectives for the Cocos (Keeling) Islands. This report summarises the research on three invertebrate groups (holothurians, Lambis lambis and giant clams) that were highlighted as high-risk, either due to lack of knowledge and/or current/potential fishing pressure. The key findings of the research projects are discussed below

Mapping shallow water habitats of the Wallabi Group, Houtman Abrolhos Islands, using remote sensing techniques

The use of mapping techniques to identify and quantify habitats is becoming an increasingly important tool for the effective management of marine resources. With a multitude of techniques such as remote sensing, acoustic surveys and towed video all commonly used, the decision on the methodology to use depends on the resolution of output data required to answer the objectives of the survey, the spatial extent and location of survey site as well as the associated costs of surveyin

Modelling Deep Water Habitats to Develop a Spatially Explicit, Fine Scale Understanding of the Distribution of the Western Rock Lobster, Panulirus cygnus

Background: The western rock lobster, Panulirus cygnus, is endemic to Western Australia and supports substantial commercial and recreational fisheries. Due to and its wide distribution and the commercial and recreational importance of the species a key component of managing western rock lobster is understanding the ecological processes and interactions that may influence lobster abundance and distribution. Using terrain analyses and distribution models of substrate and benthic biota, we assess the physical drivers that influence the distribution of lobsters at a key fishery site. Methods and Findings: Using data collected from hydroacoustic and towed video surveys, 20 variables (including geophysical, substrate and biota variables) were developed to predict the distributions of substrate type (three classes of reef, rhodoliths and sand) and dominant biota (kelp, sessile invertebrates and macroalgae) within a 40 km 2 area about 30 km off the west Australian coast. Lobster presence/absence data were collected within this area using georeferenced pots. These datasets were used to develop a classification tree model for predicting the distribution of the western rock lobster. Interestingly, kelp and reef were not selected as predictors. Instead, the model selected geophysical and geomorphic scalar variables, which emphasise a mix of terrain within limited distances. The model of lobster presence had an adjusted D 2 of 64 and an 80 % correct classification. Conclusions: Species distribution models indicate that juxtaposition in fine scale terrain is most important to the wester

Houtman Abrolhos Islands Fish Habitat Protection Area: A summary of marine resource use and ecological attributes

The Houtman Abrolhos Islands (Abrolhos) is an archipelago of up to 210 small islands and associated reefs located approximately 65-90 km offshore from Geraldton, Western Australia (WA). The islands and waters of the Abrolhos are of significance for both land-based and marine based values. The marine state territorial waters of the Abrolhos are managed by the Department of Primary Industries and Regional Development (DPIRD) as the Houtman Abrolhos Islands Fish Habitat Protection Area (Abrolhos FHPA). This report aims to provide a summary of the DPIRD data on aquatic resource use (e.g., aquaculture, commercial, recreational and charter fishing) and ecological attributes specific to the Abrolhos FHPA. Summary data provided here aims to assist with informing the development of the Abrolhos FHPA Draft Management Plan (2022) and further guide the development of future science and monitoring plans. This report is divided into three main sections, commercial use, recreational use and ecological attributes. The commercial use section provides an overview of nine commercial fisheries as well as the fishing tour operator and aquaculture industries, specifically their relationship to the Abrolhos FHPA. The recreational visitation section provides an overview of recreational usage data available to DPIRD for visitation to the Abrolhos FHPA. The ecological attributes section summarises fishery independent DPIRD collected or collated data to assist with informing overall ecosystem health and ecological functions of the Abrolhos FHPA. Where appropriate, recommendations are provided for further integration of science and management between the commercial and recreational activities, ecological attributes, and the Abrolhos FHPA

Mapping shallow water habitats of the Wallabi Group, Houtman Abrolhos Islands, using remote sensing techniques

The use of mapping techniques to identify and quantify habitats is becoming an increasingly important tool for the effective management of marine resources. With a multitude of techniques such as remote sensing, acoustic surveys and towed video all commonly used, the decision on the methodology to use depends on the resolution of output data required to answer the objectives of the survey, the spatial extent and location of survey site as well as the associated costs of surveyin

Turning up the heat: Increasing temperature and coral bleaching at the high latitude coral reefs of the Houtman Abrolhos Islands

Background: Coral reefs face increasing pressures particularly when on the edge of their distributions. The Houtman Abrolhos Islands (Abrolhos) are the southernmost coral reef system in the Indian Ocean, and one of the highest latitude reefs in the world. These reefs have a unique mix of tropical and temperate marine fauna and flora and support 184 species of coral, dominated by Acropora species. A significant La Niña event during 2011 produced anomalous conditions of increased temperature along the whole Western Australian coastline, producing the first-recorded widespread bleaching of corals at the Abrolhos. Methodology / Principal Findings: We examined long term trends in the marine climate at the Abrolhos using historical sea surface temperature data (HadISST data set) from 1900–2011. In addition in situ water temperature data for the Abrolhos (from data loggers installed in 2008, across four island groups) were used to determine temperature exposure profiles. Coupled with the results of coral cover surveys conducted annually since 2007; we calculated bleaching thresholds for monitoring sites across the four Abrolhos groups. Conclusions / Significance: In situ temperature data revealed maximum daily water temperatures reached 29.54uC in March 2011 which is 4.2uC above mean maximum daily temperatures (2008–2010). The level of bleaching varied across sites with an average of,12 % of corals bleached. Mortality was high, with a mean,50 % following the 2011 bleaching event. Prior t

Western Rock Lobster Ecology – The State of Knowledge - Marine Stewardship Council - Principle 2: Maintenance of Ecosystem

The commercial fishery is managed in three zones: south of latitude 30°S (Zone C), north of latitude 30°S (Zone B) and a third offshore zone (Zone A) around the Abrolhos Islands (Figure 1.3). Effort is evenly split between the southern and northern zones through the implementation of management controls aimed at addressing zone-specific issues. These issues include different maximum size restrictions and seasonal opening and closing dates. This report focuses on the state of the western rock lobster ecology at the date of publication

Identifying and mitigating potential risks for Marine Stewardship Council assessment and certification

The assessment of a fishery against the Marine Stewardship Council (MSC) standard requires a large amount of technical knowledge and fishery information. Failure to meet the minimum requirements or to provide the necessary information may result in 'conditions' being placed on a fishery, which can increase the overall cost of maintaining certification. Thus, it is prudent for the fishery client to have a thorough understanding of any potential areas of weakness prior to undergoing assessment. This study investigates patterns in the types of conditions received by MSC certified fisheries to identify common risk areas based on general fishery characteristics, such as target species, fishing method and geographic region.\ud \ud Fisheries targeting crab/lobster, large pelagic finfish and flatfish, and fisheries operating in the UK/Europe and the NE Pacific regions, received more conditions related to the target species' stock status (MSC Principle 1) than other groups investigated. Ecosystem (MSC Principle 2) conditions were more frequently received by fisheries using demersal trawl or longline methods compared to hand collection, line fishing or other types of netting. A high proportion of shrimp and crab/lobster fisheries, fisheries in the NW Atlantic region and dredge fisheries received Governance/Management (MSC Principle 3) conditions.\ud \ud Case studies from five types of frequently-certified fisheries are used to identify mitigation strategies for common high-risk areas. The identification and mitigation of risk areas has important implications particularly for small-scale and developing-country fisheries that have limited resources and therefore need to minimise the number of conditions received. Similarly, the identification of common risks areas highlights where more explicit guidance needs to be incorporated into future reviews of the MSC standard, e.g. Harvest Control Rules, to assist prospective fisheries and to ensure consistency in assessments