Development of the primary bacterial microfouling layer on antifouling and fouling release coatings in temperate and tropical environments in Eastern Australia.

The role played by bacteria during the pioneering stages of colonisation on marine coatings was investigated over three distinct seasons in both tropical and temperate environments. Novel methods were developed to facilitate the study of the adhered bacterial population on the test coatings in their native, hydrated state. The approach eliminated destructive sample preparation techniques, including sample dehydration and/or removal from the substratum surface prior to analysis. Bacterial colonisation during initial biofilm formation was evaluated on two antifouling paints, Intersmooth 360 and Super Yacht 800, and a fouling release coating, Intersleek 700. Bacterial colonisation was quantified on all three coating surfaces. Intersleek 700 displayed the quickest colonisation by bacteria, resulting in major modification of the substratum surface within 2-4 days following immersion in the ocean. Whilst fouling accumulated more quickly on Intersleek 700, by 16 days all three coatings were fouled significantly. Bacterial fouling was correlated to both location and season, with fouling occurring at a more rapid rate at the Cairns location, as well as during the summer months, when higher water temperatures were recorded. Successful colonisation of all coatings by bacteria soon after immersion modifies the characteristics of the surfaces at the hull/water interface, and subsequent settlement by higher biofouling organisms must be moderated by these modified surfaces.

Linguistic uncertainty in qualitative risk analysis and how to minimize it.

Most risk assessments assume uncertainty may be decomposed into variability and incertitude. Language is often overlooked as a source of uncertainty, but linguistic uncertainty may be pervasive in workshops, committees, and other face-to-face language-based settings where it can result in misunderstanding and arbitrary disagreement. Here we present examples of linguistic uncertainty drawn from qualitative risk analysis undertaken in stakeholder workshops and describe how the uncertainties were treated. We used a process of iterative re-assessment of likelihoods and consequences, interspersed with facilitated discussion, to assist in the reduction of language-based uncertainty. The effects of this process were evident as changes in the level of agreement among groups of assessors in the ranking of hazards.

Risk-based approaches to deal with uncertainty in a data-poor system: stakeholder involvement in hazard identification for marine national parks and marine sanctuaries in Victoria, Australia.

Management responsibilities for the system of marine national parks and sanctuaries declared in Victoria, Australia in 2002 have created imperatives for robust, scientifically defendable approaches to identifying threats to valued ecological attributes of the parks, setting management priorities, and developing monitoring systems. We are developing a protocol for ecological risk assessment in the parks that has due regard for the perception of risks by individuals, and ensures that stakeholder values are an intrinsic part of decision making. The inclusive and transparent protocol provides an opportunity for stakeholder involvement in the identification of valued attributes, as well as in the assessment of associated risks. Our approach brings together ideas about how science enters the community engagement domain in ways that promote collaboration and transparency in decision making. A series of stakeholder workshops across the state drew on the expertise of agency staff, community groups, fishers, industry representatives, academics, and knowledgeable park neighbors to identify hazards of major concern in the parks. Many hazards involved predictable, tangible threats like pollution and exotic species, but the approach also identified a number of less obvious threats related to governance issues and the knowledge-base for the parks. Importantly, the workshops with their broad range of stakeholders identified threats not previously considered by the management agency in its internal assessments, and several of these "new" threats are already the subject of action by the agency. The deliberate incorporation of local knowledge and local networks in the risk assessment process also provided opportunities for greater engagement of stakeholders with the management agency.

The variability of estimates of variance, and its effect on power analysis in monitoring design.

Power analysis can be a valuable aid in the design of monitoring programs. It requires an estimate of variance, which may come from a pilot study or an existing study in a similar habitat. For marine benthic infauna, natural variation in abundances can be considerable, raising the question of reliability of variance estimates. We used two existing monitoring programs to generate multiple estimates of variance. These estimates were found to differ from nominated best estimates by 50% or more in 43% of cases, in turn leading to under or over-estimation of sample size in the design of a notional monitoring program. The two studies, from the same general area, using the same sampling methods and spanning a similar time scale, gave estimates varying by more than an order of magnitude for 25% of taxa. We suggest that pilot studies for ecological monitoring programs of marine infauna should include at least two sampling times.