Large-scale patterns in puerulus settlement and links to fishery recruitment in the southern rock lobster (Jasus edwardsii), across south-eastern Australia

Abstract

Monthly monitoring of puerulus settlement across South Australia, Victoria and Tasmania has been undertaken since the early 1990s. Firstly, annual trends in settlement were spatially analysed across the three States. In South Australian and Victorian settlement patterns were closely related. In Tasmania, settlement sites along the northeast coast were positively correlated, but showed no relationship with areas further south or in any other State. Secondly, annual settlement indices were correlated with lagged estimates of fishery recruitment. In South Australia, the strongest correlations between settlement and recruitment to legal size were observed using a 4–5- year time-lag. Within Victoria and Tasmania, the period from settlement to recruitment at 60 mm carapace length (CL) was 2 and 3 years, respectively. The period from 60 mm to legal size was another 2–3 years, suggesting that the total time from settlement to the fishery ranges from 4–6 years in these regions. The correlation between settlement and recruitment was used to forecast future estimates of exploitable biomass in one region of South Australia. The results indicate that puerulus monitoring is a relatively robust indicator of future fishery performance and should be regarded as an important data source for rock lobster resources within south-eastern Australia.

Differing environmental drivers of settlement across the range of southern rock lobster (Jasus edwardsii) suggest resilience of the fishery to climate change

“…Settlement magnitude of J. edwardsii has been monitored monthly by fisheries management agencies in Australia and in New Zealand from the early 1990s by counting pueruli and early juveniles in sets of crevice collectors (Booth and Tarring, ) usually deployed on sand adjacent to shallow coastal reefs (Cohen and Gardner, ; Booth and McKenzie, ; Linnane et al ., ). Crevice collectors consist of angled plywood sheets that mimic natural crevice habitat, and the monthly survey procedures involve a diver who first places a mesh bag around the collector and then hauls it to the surface for counting the catch (Booth and Tarring, ).…”

“…After 11 phyllosoma developmental stages, the larvae metamorphose to a puerulus stage as far as 200 km offshore before actively swimming shoreward in search of small holes and crevices in coastal rocky reef habitats in which to settle (Jeffs et al ., , ; Bradford et al ., ). Settlement mainly occurs at night, is highly seasonal, and can vary by location and magnitude from year to year (Booth et al ., ; Cohen and Gardner, ; Linnane et al ., ). The prolonged and variable larval period in this species means that pueruli settling in some months may originate from two consecutive annual spawning events (Bradford et al ., ).…”

“…Monitoring of settlement in J. edwardsii on artificial collectors has been undertaken throughout their distribution range for 20–30 years and has been used as a predictor of future recruitment to fishable biomass in some regions (Gardner et al ., ; Booth and McKenzie, ; Linnane et al ., , ). Monitoring of settlement in other spiny lobster fisheries has enabled the identification of environmental signals affecting settlement (Caputi, ; but see de Lestang et al ., ) and the impact of changes in the size of the adult breeding population (e.g., Ehrhardt and Fitchett, ).…”

The Environmental Impact of Two Australian Rock Lobster Fishery Supply Chains under a Changing Climate

“…et al. ), and the SRL fishery is no exception. At 13.8 kg CO 2 ‐eq kg −1 , lobster at capture emissions per kg exceed large‐scale industrial fishing methods, such as trawling for small pelagic fishes, by 35 times (Driscoll and Tyedmers ; Ziegler et al.…”

Swimming responses of larval and juvenile freshwater fishes to nearshore and offshore water sources

“…Such large lakes generally exhibit many of the same oceanographic processes (Pritt et al, 2014) such as long-distance currents (Beletsky, Saylor, & Schwab, 1999), and upwelling and downwelling processes (Rao & Schwab, 2007) found in marine systems. Such large lakes generally exhibit many of the same oceanographic processes (Pritt et al, 2014) such as long-distance currents (Beletsky, Saylor, & Schwab, 1999), and upwelling and downwelling processes (Rao & Schwab, 2007) found in marine systems.…”