The current method of measuring undersize lobster abundance (PRA) is based on catch data adjusted for multiple biases inherent in commercial monitoring, namely: water depth, water temperature, swell, fisher experience, pot type, escape gaps, pot pulling time, month and location. Biases are exacerbated by recent poor sample sizes, as many fishers choose not to fish in shallow-water areas. Developing a standardized, repeatable survey in shallow areas will provide an improved index of PRA that can be incorporated into the stock modelling: this would improve the overall assessment.
Currently fishery-independent survey data collection requires a minimum of two staff to process the catch and record information. Data entry is conducted by a third staff member. To increase cost effectiveness (for this and other lobster surveys), a more efficient data collection system is needed. Initial scoping has identified a number of possible solutions (e.g. app-based entry). This project will expand on this original scoping work to develop a solution. This will also benefit commercial lobster monitoring work conducted by DPIRD as well as a range of other surveys in similar pot based fisheries.
This survey will also provide a platform for monitoring inshore WRL habitats. This will establish a baseline against which further research into the relationships between WRL and their near shore habitats can be undertaken. This will assist with detecting and quantifying habitat shifts that may impact the fishery. For example, there is anecdotal evidence that the heatwave temporarily modified some of these near shore habitats, leading to the altered relationship between puerulus and lobster recruitment. Long-term monitoring of juvenile habitats will likely provide a useful indicator of one of the factors affecting recruitment to the fishery.

The marine heat waves (MHW) of 2010/11, 2011/12 and 2012/13 provide a benchmark with which to investigate changes in habitat composition and potential flow on effects to the fishery.

A 2018 independent review of the science used for stock assessment of the fishery recommended that studies should be undertaken to

a) investigate the impacts of the previous MHW on juvenile recruitment to the fishery and,

b) to better understand the role of habitat composition in recruitment

To understand the impact of habitat change on the fishery, either through warming events or changes in coastal processes, we need an increased understanding of the role of habitat on the survivorship and growth of puerulus, post-puerulus, juvenile and adult life stages of lobster.

In the 40 year time-series of puerulus settlement index a very strong relationship has persisted between puerulus abundance and commercial lobster catches 3 - 4 years larter (de lestang et al., 2010). An undersize catch rate index, based on historical (1985 - present) catch-rate records, evidenced the existence of a strong correlation between puerulus and undersize catch rate (de Lestang pers. com.). However, two-four years after the MHW of 2010/11, this relationship degraded, with the observed catch rate of lobsters being far less than expected at northern locations of the fishery. Although the relationship has now started to return to its historical form, the severity and longevity of its departure are cause for concern and highlight the marked impact future MHW or changes in coastal processes could have on the fishery.

Change in the extent and configurations of coastal habitats is already occurring in response to natural physical forcing (coastal processes) and accelerated by climate change related stressors. It is crucial to have a detailed knowledge of how habitat change affects survival and recruitment key life-stages of the western rock lobster, so these can be taken into consideration for management practices that ensure the sustainability of the fishery. Such information is currently lacking.