Observations of the association by early-juvenile western rock lobster Panulirus cygnus George, 1962 with seagrass assemblages (Decapoda: Achelata: Palinuridae)

Authors

Daphne Oh, University of Western AustraliaFollow
Tim J. Langlois, University of Western AustraliaFollow
Michael A. Brooker, University of Western Australia
Hugo Salinas, University of Western Australia
Jason R. How, Department of Primary Industries and Regional Development, Western AustraliaFollow
Simon de Lestang, Department of Fisheries, Western AustraliaFollow

Document Type

Article

Publication Date

8-23-2023

Journal Title

Journal of Crustacean Biology

ISSN

Print: 0278-0372 Electronic: 1937-240X

Keywords

Amphibolis, Crustacea, global climate change, marine heatwaves, mesocosms, microhabitats, post-puerulus stage, seagrasses

Disciplines

Aquaculture and Fisheries | Terrestrial and Aquatic Ecology

Abstract

The fishery of the western rock lobster, Panulirus cygnus George, 1962, is Australia’s most valuable wild-caught single-species fishery. Recruitment in some regions of the fishery was observed to be significantly lower than expected after the 2010/2011 West Australian marine heatwave that caused extensive disturbance of dominant coastal habitats. This event generated interest in the study of the factors influencing survival and recruitment of post-larval benthic P. cygnus after settlement. The habitat associations of the highly cryptic post-settlement early-juveniles were previously unknown, with only anecdotal observations of individuals within limestone crevices in nearshore habitats. Our study used early-juveniles derived from ongoing monitoring of puerulus settlement to examine their habitat association mechanism in mesocosm experiments. Comparison of common nearshore habitat assemblages (bare sand, limestone crevices, and seagrasses (Posidonia and Amphibolis) at varying seagrass densities) found that most early-juveniles associated strongly with Amphibolis assemblages at high stem densities (~2,100 stems m–2). A shift in association between Amphibolis fronds and stems at high stem density to Amphibolis-shaded sand and leaf debris at low stem density indicated active habitat selection by early-juveniles. Habitat choices were tested with the scents of prey items and habitat types within Amphibolis assemblages using Y-maze bioassays. No significant olfactory choices were found, suggesting that habitat associations may be driven by multiple cues. Our study provides new laboratory-based insights into the habitat association of early-juvenile P. cygnus and suggests changes in seagrass assemblage identity and density are likely to be important. Further experimentation is needed to define the cues driving these patterns. The impact of habitat change on recruitment in this important fishery remains unknown and should be an objective of future research.

Recommended Citation

Daphne Oh, Tim J Langlois, Michael A Brooker, Hugo Salinas, Jason R How, Simon N de Lestang, Observations of the association by early-juvenile western rock lobster Panulirus cygnus with seagrass assemblages (Decapoda: Achelata: Palinuridae), Journal of Crustacean Biology, Volume 43, Issue 3, September 2023, ruad045, https://doi.org/10.1093/jcbiol/ruad045