A quantitative study of nocturnal foraging distances of the western rock lobster Panulirus cygnus George

1988 ◽  
Vol 35 (6) ◽  
pp. 568
Keyword(s):  
Quantitative Study ◽  
Rock Lobster ◽  
Nocturnal Foraging ◽  
Panulirus Cygnus ◽  
Foraging Distances

scholarly journals Stocking density and shelter type for the optimal growth and survival of western rock lobster Panulirus cygnus (George)

Aquaculture ◽  
2006 ◽  
Vol 260 (1-4) ◽  
pp. 114-127 ◽  
Author(s):  
Danielle Johnston ◽  
Roy Melville-Smith ◽  
Blair Hendriks ◽  
Greg B. Maguire ◽  
Bruce Phillips
Keyword(s):  
Stocking Density ◽  
Optimal Growth ◽  
Rock Lobster ◽  
Growth And Survival ◽  
Panulirus Cygnus

Spatial and temporal variation in lipid and fatty acid profiles of western rock lobster pueruli at first settlement: biochemical indicators of diet and nutritional status

2009 ◽  
Vol 60 (8) ◽  
pp. 810 ◽  
Author(s):  
A. J. Limbourn ◽  
R. C. Babcock ◽  
D. J. Johnston ◽  
P. D. Nichols ◽  
B. Knott
Keyword(s):  
Fatty Acid ◽  
Nutritional Status ◽  
Spatial And Temporal Variation ◽  
Lipid Levels ◽  
Rock Lobster ◽  
Important Species ◽  
Fa Composition ◽  
Lipid Fatty Acid ◽  
Spatial And Seasonal Variation ◽  
Panulirus Cygnus

Rock lobster species are found worldwide and have a life history that includes development through a planktonic phyllosoma followed by a nektonic non-feeding puerulus that relies on stored energy during recruitment into near-shore habitats. Recruitment to adult populations of western rock lobster (Panulirus cygnus) is highly variable and is likely to be strongly influenced by shelf width and oceanic conditions affecting cross-shelf transport and nutrition. Since the nutritional status of newly settled pueruli will reflect the phyllosoma feeding environment and distance swum, we studied levels of lipid, fatty acid (FA) and protein of 422 pueruli and 79 first instar juveniles from four Western Australian locations. Lipid levels generally were inversely related to shelf width but were variable, suggesting pueruli may travel complex trajectories to coastal settlement. Lipid and FA composition of pueruli were consistent with spatial and seasonal variation in Leeuwin Current and coastal productivity regimes. Seasonal differences in FA composition occurred regardless of the year of settlement. Pueruli had lower lipid levels during ENSO years, when recruitment tends to be lower also. Measures of puerulus nutritional status appear to provide valuable insights into the processes underpinning recruitment in Panulirus cygnus and other commercially and ecologically important species.

Genetic structure of the western rock lobster, Panulirus cygnus, with the benefit of hindsight

1996 ◽  
Vol 47 (7) ◽  
pp. 889 ◽  
Author(s):  
AP Thompson ◽  
JR Hanley ◽  
MS Johnson
Keyword(s):  
Genetic Structure ◽  
Western Australia ◽  
Allozyme Variation ◽  
Genetic Homogeneity ◽  
Latitudinal Variation ◽  
Rock Lobster ◽  
Polymorphic Loci ◽  
Allelic Frequencies ◽  
Genetic Subdivision ◽  
Panulirus Cygnus

Allozyme variation was used to investigate the genetic structure of the western rock lobster, Panulirus cygnus, along the coast of Western Australia. The study involved genetic surveys in 1980 and 1994. The first survey showed strong suggestions of latitudinal variation at two polymorphic loci, EST and GPI, but these suggestions were statistically suspect. With the benefit of hindsight gained from 1980, the 1994 survey was designed to examine more directly the suggestion of latitudinal genetic subdivision in this species. No evidence of genetic subdivision was found at either the EST or the GPI locus. In addition, the average FST value over nine polymorphic loci was a very low 0.0002. The evidence is consistent with current interpretations that P. cygnus is a single, panmictic population. In contrast with this spatial genetic homogeneity, however, there were significant changes in allelic frequencies at the GPI locus between 1980 and 1994, indicating genetic differences among cohorts.

scholarly journals The orientation and migratory dynamics of the western rock lobster, Panulirus cygnus, in Western Australia

2014 ◽  
Vol 71 (5) ◽  
pp. 1052-1063 ◽  
Author(s):  
Simon de Lestang
Keyword(s):  
Large Scale ◽  
Economic Benefits ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Breeding Grounds ◽  
Mean Size ◽  
Catch Rates ◽  
Panulirus Cygnus ◽  
The Impact ◽  
Oceanic Currents

Abstract Large-scale migrations are known to occur in numerous species, and in the case of the Western Rock Lobster, Panulirus cygnus, result in juveniles moving from nursery areas into deeper offshore breeding grounds. In 2008 the Western Rock Lobster fishery reduced harvest rates to increase legal and spawning biomass throughout the fishery, which also allowed greater numbers of lobsters to migrate. Increased lobster migration could potentially reduce biomass in some areas, thus adversely impacting commercial catch rates. Over 20 000 tag–recaptured lobsters were analysed to determine the dynamics underlying migration in this species and to assess the impact reduced harvest rates may have had on catches. This study showed that P. cygnus migration was associated with body size and water depth, and that magnetism and oceanic currents appear to be the most likely guideposts used for orientation. Size at migration varied in a constant fashion along the coast, being larger towards the southern end of the fishery and smallest at the offshore Abrolhos Islands. During the migration period, up to 50% of lobsters at their mean size of migration moved from coastal areas out towards deeper waters (>40 m), whereas <15% of those in deeper water at the same size moved significant distances northward. This behaviour appears to be contranatant, counteracting the downstream redistribution of larvae after their 9–11 month larval life. Reduced harvest rates and catches being focussed onto higher valued sedentary lobsters have allowed more lobsters to migrate. However, the numbers moving between management areas are relatively small, with the biological and economic benefits of fishing at a reduced exploitation rate outweighing losses to catches.

Fish predators of the western rock lobster (Panulirus cygnus George) in a nearshore nursery habitat

1988 ◽  
Vol 39 (3) ◽  
pp. 307 ◽  
Author(s):  
RK Howard
Keyword(s):  
Fish Species ◽  
Fish Community ◽  
Carapace Length ◽  
Nursery Habitat ◽  
Rock Lobster ◽  
Lack Of Information ◽  
Gill Net ◽  
Fish Predators ◽  
Panulirus Cygnus ◽  
A Current

Nearshore limestone reefs of Western Australia represent an important nursery habitat for juveniles of the western rock lobster (Panulirus cygnus). As part of a trophic study of the fish community associated with these reefs, fishes were examined for evidence of predation on western rock lobsters. Six fish species were found to have ingested P. cygnus. Of these, Psammaperca waigiensis (sand bass), Pelsartia humeralis (sea trumpeter), Pseudolabris parilis (brown-spotted wrasse) and Plectorhyncus flavornaculatus (gold-spotted sweetlips) were among the ten most abundant fish in gill-net collections from the study site. P. cygnus formed a significant portion of the diet of P. waigiensis, but was < 5% of the dietary volume of other species. Predation occurred at all times of the day and was concentrated on small, newly-settled P. cygnus (8-15 mm carapace length). The vulnerability of lobsters to predation appears to be strongly related to size, and the cryptic habits that are unique to newly-settled stages can be explained in terms of the risks of predation. Assessment of the proportion of mortality of P. cygnus due to predation is hampered by a current lack of information on the natural densities of both fishes and small rock lobsters. However, conservative estimates indicate that an annual removal by fish of thousands of lobsters per hectare is likely, suggesting that predation is a major factor affecting the survival of P. cygnus on nursery reefs.

scholarly journals Variation in evacuation rates of different foods skew estimates of diet in the western rock lobster Panulirus cygnus

2008 ◽  
Vol 59 (4) ◽  
pp. 347 ◽  
Author(s):  
Kris Waddington
Keyword(s):  
Content Analysis ◽  
Coralline Algae ◽  
Gut Content Analysis ◽  
Feeding Period ◽  
Gut Content ◽  
Rock Lobster ◽  
Panulirus Cygnus

Knowledge regarding differences in evacuation rates of diet items from a consumer’s stomach is important when using gut content analysis to quantify consumer diet. Evacuation rates of three diet items (pilchards, crabs and coralline algae) from the foreguts of western rock lobsters (Panulirus cygnus) were compared in aquaria. To determine evacuation rates, lobsters were allowed to consume offered food over a 90-min feeding period before being killed at 4, 6, 8, 10 and 12 h after the feeding period concluded. Diet items differed in their rate of evacuation from lobster foreguts with coralline algae evacuated most rapidly, followed by crabs, then pilchards. The evacuation of crabs and pilchards was still not complete 12 h after the feeding period concluded. Food not evacuated after 12 h predominantly consisted of hard components of the lobster diet, indicating that it is these components that account for slower evacuation. Observed variation in evacuation rates between diet items may skew the results of studies that use gut content analysis to quantify the diet of western rock lobsters.

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