Budget expenditure: $237,535.00
Project Status:
Current
Principal Investigator: Tim J. Langlois
Organisation: University of Western Australia (UWA)
Project start/end date: 1 Jul 2020 - 1 Nov 2022
Contact:
FRDC
TAGS
Wild Catch
Threatened Endangered Protected Species
Stock Assessment
Stakeholder
Safety
SPECIES
Western Rock Lobster

Need

In Western Australia, the positive and negative effects of SGD in marine benthic communities remains unknown. In Marmion Lagoon, SGD is known to supply up to 50% of the nutrients required for the macrophyte growth rates observed (Johannes and Hearn 1985). Freshwater input has been observed to positively impact seagrass germination (Xu et al., 2016), and although no similar studies exist for temperate seagrass species in the southern hemisphere, SGD may have a role in the creation, maintenance and augmentation of seagrass beds.
The direct influence of SGD on puerulus settlement rates is unknown but freshwater discharge has been shown to be positively correlated with crab larval abundance (Boylan and Wenner, 1993). An ongoing FRDC project (2016-260: Assess causes and implications of anomalous low lobster catch rates) has demonstrated post-puerulus western rock lobster exhibit a strong choice for the chemical signature of seagrass (Brooker et al. in prep). These findings suggest that SGD may affect puerulus settlement rates either directly through chemotaxis or indirectly by impacting the density of seagrass meadows. Hence, there is a need to investigate both the role of SGD and the presence of seagrass on puerulus settlement rates.
Land derived contaminants potentially impacting puerulus settlement and survival could include heavy metals and endocrine disrupting chemicals, such as flame-retardants or pesticides targeting insects (McKenney, 1999). Adult lobster have been shown to be repelled by the presence of copper (McLeese, 1975) and both flame-retardants (polybrominated diphenyl ethers - PBDEs) (Davies and Zou, 2012) and various insecticides (Ghekiere et al., 2005) have been shown to disrupt moulting in marine crustacea. Alkylphenol pollution was implicated in a major die-off of the American lobster (Homarus americanus) population that occurred in Long Island Sound in 1999, with acute impact on post-puerulus mortality during moulting (Laufer et al., 2013). There is a need to investigate both the occurrence and concentration of likely contaminants at potential source locations within the Western Rock Lobster fishery and assess their impact on post-puerulus survival.

Objectives

1. Identify areas of significant submarine groundwater discharge (SGD) nearby established western rock lobster settlement monitoring sites.
2. Investigate the direct role of SGD on western rock lobster settlement rates.
3. Investigate the link between SGD and the extent and condition of important lobster habitat (e.g. seagrass).
4. Identify and map input of contaminants by SGD in key fishery areas.
5. Investigate impact of contaminants on the survival of puerulus and post-puerulus lobster.

Related research

Communities
Environment
Environment