Mike Van Keulen

SSurveys were undertaken of key invertebrate and plant groups in lagoon areas throughout the Ningaloo Marine Park, focussing on identifying and quantifying soft corals, sponges, echinoderms (urchins and sea cucumbers) and seagrasses; this information was linked to the underlying habitat structure in the Ningaloo Reef lagoons, used in a parallel habitat mapping project based on hyperspectral aerial photography. The biodiversity surveys conducted throughout the Ningaloo Reef system have shown that there are clear differences in the lagoon systems in different parts of the Marine Park, with clear biogeographic separation of sponges, soft corals and seagrasses. This has important implications for the distribution and abundance of many animals, including some of commercial importance. The northern section of the Marine Park (north of Point Cloates) is more strongly tropical than the southern section, which has many temperate species present. There are also several locations within the Ningaloo Reef system that are quite unique and don’t necessarily match the surrounding lagoon environment. Examples include Coral Bay, Bateman Bay and the Point Cloates region. These observations will be important in the management of the Ningaloo Marine Park; the northern and southern sections of the Marine Park may need to be managed differently. Surveying biological groups over the whole Marine Park is difficult and time consuming; further sampling in more locations and at different times of year are required to build on the findings of our study. There are clear seasonal differences in primary productivity in the lagoons, which likely drive significant community-wide changes throughout the year. These seasonal variations will also affect the validity of the habitat maps, which were based on imagery collected at only one time of year. Seasonal sampling will improve the reliability of the habitat maps and also give a better understanding of how the Ningaloo system operates.

The overall objective of this research project is to add to the general understanding of coral reef ecology and more specifically, advance the existing knowledge of the role of sea urchins in coral reef ecology at Ningaloo Marine Park. This study will examine marine grazers (particularly sea urchins), investigating their habitats, home range, reproduction, distribution, larval recruitment and settlement, and trophic relationships at Ningaloo Marine Park. The indirect effects of different closure regimes (e.g. Marine Protected Areas (MPA’s) such as sanctuary zones) on urchin ecology within Ningaloo Marine Park will be examined at length, both temporally and spatially over the next two to three years and will provide important new information which will aid in the formulation of future management strategies for the conservation and stewardship of Ningaloo Marine Park.

This project is part of the CSIRO Flagship Wealth from Oceans, Ningaloo Cluster: “Reef use, biodiversity and socio economics for integrated management strategy evaluation of Ningaloo”. This project is run from Murdoch University in collaboration with Curtin and Queensland Universities. Airborne hyperspectral data have been acquired by HyVista through the efforts of AIMS and sponsored by BHP Billiton. The project is focusing on the mapping of habitats and biodiversity of the Ningaloo Marine Park. This is being achieved through a combination of state-of-the-art hyperspectral remote sensing techniques, coupled with biodiversity field surveys of the area.

Summary: The last reported extent of seagrass coverage in the Wagonga Inlet, Narooma was given as 148 ha, although estimates of seagrass coverage vary considerably. The channel area consists of approximately 4 ha or 2.7% of this total coverage. The bare sand flats adjacent to the channel are naturally colonising at a reasonably rapid rate (c.a. 1 m y-1). That seagrasses are healthy in the inlet is illustrated by the fact that they are growing successfully underneath jetties, boardwalks and oyster leases. Additionally, in the quite turbid environment of the upper reaches of the inlet, Zostera sp. is growing well. Any factor that would increase this turbidity such as runoff from land clearing would be expected to impact upon these communities and possibly reduce their range. However sediments in the channel between Mill and Forsters Bay are more coarse and turbidity caused by dredging would be expected to be short-lived; and, if carried out at the appropriate time of year would be expected to have minimal impact upon adjacent seagrasses. After more than a year pilot seagrass transplantation trials on the sand flats adjacent to the channel have shown 92% survival. In addition there has been natural colonisation in this area by both seedlings and seagrass fragments within and around the transplant area. Recent data on transplantation trials in another NSW estuary have also shown good survival. This indicates that the seagrasses in the Narooma Inlet may neither be under stress nor are they decreasing in area and that seagrass transplantation may be a viable method to increase meadow area. Dredging a channel would remove approximately 2.7 % of the seagrasses in the inlet adjacent to a seagrass meadow that is naturally colonising and of a greater size. The bare sand flat area is approximately 40 ha and might be expected to support at least half of this as seagrass meadows in the future. It would be possible to augment the colonisation by further transplantation of the appropriate methodology using material which would be dredged from the channel. Therefore if a channel is dredged to attract tourist boat usage during holiday periods, its total impact upon seagrass meadows in the inlet is likely to be minimal.

Ningaloo Reef is internationally recognized as a highly productive and biodiverse marine ecosystem of potential World Heritage listing. Currently, this fringing barrier reef system and its coasts are subject to significant human pressure. Unlike the Great Barrier Reef, Ningaloo Reef is particularly susceptible to visitor disturbance due to its unique proximity to the coast. Coral Coast Marina Development Pty Ltd (CCMD) has proposed an inland marina style resort complex at Bateman Bay. The condition of the marine and coastal environment forms the central focus of attraction for this development. CCMD’s baseline data collection of these integral environmental components was considered insufficient to predict potential impacts. Due to the scale and nature of this proposal and the biodiversity significance of the Ningaloo Reef, information describing the pre-development condition of the marine environment was considered essential.

Ningaloo Reef is internationally recognized as a highly productive and biodiverse marine ecosystem of potential World Heritage listing. Currently, this fringing barrier reef system and its coasts are subject to significant human pressure. Unlike the Great Barrier Reef, Ningaloo Reef is particularly susceptible to visitor disturbance due to its unique proximity to the coast. Coral Coast Marina Development Pty Ltd (CCMD) has proposed an inland marina style resort complex at Bateman Bay. The condition of the marine and coastal environment forms the central focus of attraction for this development. CCMD’s baseline data collection of these integral environmental components was considered insufficient to predict potential impacts. Due to the scale and nature of this proposal and the biodiversity significance of the Ningaloo Reef, information describing the pre-development condition of the marine environment was considered essential.

Cockburn Cement Limited operates the largest cement manufacturing works in Western Australia and the largest lime manufacturing works in Australia. Cockburn has dredged shellsand from local coastal waters since 1972 in accordance with the Cement Works (Cockburn Cement Limited) Agreement Act. To gain approval for medium term access, Cockburn had to prepare an acceptable Environmental Management Plan, incorporating details of a number of studies, including the feasibility of rehabilitating seagrass (Project S2). This document summarises the S2 project from its inception, which was designed to take place in two phases; the first consisted largely of a review of relevant literature and data, and the second was the work program itself. The following scope of work was identified for Phase 1; complete a review of the seagrass rehabilitation literature, design and scope field studies, undertake an assessment of the availability of sites for use in large-scale seagrass rehabilitation and recommend an approach to be undertaken in Phase 2 of the study. A synthesis report was produced which provided an assessment of the condition of the project area for accommodating seagrass rehabilitation, based on available information, and recommendations on the approach, scope of work and tasks for the next phase of the project. Phase 2 encompassed the process of site selection, manual experimental work carried out to augment mechanical transplantation, and the development of mechanical transplantation. The site selection process culminated in the production of a table of potential sites identifying various relevant characteristics of each location. From this list, sites were identified for different purposes within the project such as donor supply and recipient locations.