Connectivity Modelling to Protect Coral Spawning during Dredging

Project Sheet [snippet]

Regulatory authorities in Australia have sought to protect coral spawning events from potential adverse impacts caused by elevated levels of suspended sediment generated from dredging activities.

The recent Reef 2050 Long Term Sustainability Plan proposes action to identify appropriate environmental windows to avoid dredging operations during coral spawning as part of a state-wide maintenance dredging strategy to be developed by the Department of Transport and Main Roads (WQA16). However, coral spawning typically occurs multiple times throughout the year and latest research indicates dredging would need to cease for a few months before and after spawning events to protect coral reefs from the effects of sediments on coral reproduction (Jones et al. 2015).

This would significantly limit time that dredging could occur near coral reefs in any given year. Avoiding dredging during these windows may not be feasible as unscheduled changes is likely to result in costly delays or significant interruptions to port operations.

 

Modelling coral reef connectivity provides an innovative management approach for ports to assess the risk of potential impacts from dredging during coral spawning windows. Modelling connectivity reveals the demographic linkage of local populations through the exchange of coral larvae. When coupled with the results for dredge modelling, evaluation of coral reef connectivity enables a quantitative risk-based management approach through assessing a range of operational control measures, such as modifying the dredging technique, location or spoil disposal area, to direct spill sources away from key reef areas and coral larval dispersal patterns….

 

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