Increased density, biomass and egg production in an unfished population of Western Rock Lobster (Panulirus cygnus) at Rottnest Island, Western Australia

2007 ◽  
Vol 58 (3) ◽  
pp. 286 ◽  
Author(s):  
R. C. Babcock ◽  
J. C. Phillips ◽  
M. Lourey ◽  
G. Clapin
Keyword(s):  
Western Australia ◽  
Carrying Capacity ◽  
Egg Production ◽  
Carapace Length ◽  
Spiny Lobster ◽  
Shallow Waters ◽  
Recreational Fishing ◽  
Total Biomass ◽  
Rock Lobster ◽  
Panulirus Cygnus

Surveys of spiny lobster (Panulirus cygnus) populations in shallow waters surrounding Rottnest Island in Western Australia revealed much higher levels of density, biomass and egg production in no-take than in fished areas. Density of lobsters was ~34 times higher in the sanctuary, and density of lobsters above minimum legal size around 50 times higher than in other areas around the island where recreational fishing is allowed. Mean carapace length (CL), total biomass and egg production of lobsters in the sanctuary zone were significantly higher than in adjacent fished areas. Large individuals (≥100 mm CL), especially large males, were found almost exclusively within the sanctuary. The abundance of mature animals in these shallow waters indicates that not all P. cygnus migrate to deep water and that shallow water habitats may currently be well below carrying capacity in terms of biomass and egg production. If implemented in a systematic way, unfished areas such as the Kingston Reefs could also provide a useful fisheries-independent tool for assessing trophic interactions and the structure and density of unfished populations, and for estimating parameters such as growth of larger individuals that may be rare or absent in more widely fished populations.

Predicting the recreational western rock lobster (Panulirus cygnus) catch in Western Australia

2001 ◽  
Vol 52 (8) ◽  
pp. 1527 ◽  
Author(s):  
Roy Melville-Smith ◽  
Sonia M. Anderton ◽  
Nick Caputi
Keyword(s):  
Western Australia ◽  
Coastal Management ◽  
Southern Region ◽  
Recreational Fishing ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Mail Surveys ◽  
Panulirus Cygnus ◽  
Multipleregression Analysis ◽  
Better Than

The number of fishers purchasing recreational rock-lobster licences in Western Australia increased from ~15 000 during 1986–87 to 33 000 during 1998–99. The quantity landed was estimated from mail surveys conducted during this period. The recreational catch of western rock lobster increased from approximately 220 to 630 tonnes, or from 1.8% to 4.8% of the commercial catch. This study has shown that total recreational catches of western rock lobster in Western Australia are correlated with licence usage rates (r2 = 0.81) and puerulus settlement indices at Alkimos, in the southern region of the fishery, 3 to 4 years earlier (r2 = 0.59). A multipleregression analysis using both of these variables (r2 = 0.91) was used to predict future recreational lobster catches. If future usage were to remain at 1998–99 levels, it is predicted that the recreational catch would be 700 t in 1999–2000, 650 t in 2000–01, and 550 t in 2001–02. We attempted to improve predictions by analysing the data according to puerulus settlement and licence usage in the two coastal management regions. The correlation for the southern region (where most of the recreational fishing is concentrated) was marginally better than that for the total fishery (r2 = 0.93), but the correlation was poor for the northern coastal zone (r2 = 0.55), where licence usage has been relatively steady and where the recreational catch has consistently remained at around 98 t per annum over the last decade.

scholarly journals Phyllosomata associated with large gelatinous zooplankton: hitching rides and stealing bites

2014 ◽  
Vol 72 (suppl_1) ◽  
pp. i124-i127 ◽  
Author(s):  
Richard O'Rorke ◽  
Shane D. Lavery ◽  
Miao Wang ◽  
Ramón Gallego ◽  
Anya M. Waite ◽  
...  
Keyword(s):  
High Throughput ◽  
Western Australia ◽  
Late Stage ◽  
High Throughput Sequencing ◽  
Spiny Lobster ◽  
Gelatinous Zooplankton ◽  
Rock Lobster ◽  
Panulirus Cygnus

Abstract During a zooplankton survey 350 km off the coast of Western Australia, we captured a large and robust zooid of a salp (Thetys vagina), to which six late stage larvae (phyllosomata) of the western rock lobster (Panulirus cygnus) were attached. High-throughput sequencing analyses of DNA extracts from midgut glands of the larvae confirmed that each phyllosoma had consumed mainly salp tissue (x¯ = 64.5% ± 15.9 of DNA reads). These results resolve long-standing conjecture whether spiny lobster phyllosomata attach to large gelatinous hosts to feed on them.

scholarly journals Spatial and temporal changes in egg production in the western rock lobster(Panulirus cygnus)fishery

2009 ◽  
Vol 43 (1) ◽  
pp. 151-161 ◽  
Author(s):  
Roy Melville‐Smith ◽  
Simon De Lestang ◽  
Adrian W. Thomson
Keyword(s):  
Egg Production ◽  
Temporal Changes ◽  
Rock Lobster ◽  
Spatial And Temporal Changes ◽  
Panulirus Cygnus

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.

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.

Relationships Between Spawning Stock, Environment, Recruitment and Fishing Effort for the Western Rock Lobster, Panulirus Cygnus, Fishery in Western Australia

Crustaceana ◽  
1995 ◽  
Vol 68 (2) ◽  
pp. 213-226 ◽  
Author(s):  
Rhys S. Brown ◽  
Christopher F. Chubb ◽  
Nicolavito Caputi
Keyword(s):  
Western Australia ◽  
Fishing Effort ◽  
Rock Lobster ◽  
Spawning Stock ◽  
Panulirus Cygnus

The status of the western rock lobster, Panulirus cygnus, fishery and the effectiveness of management controls in increasing the egg production of the stock

2001 ◽  
Vol 52 (8) ◽  
pp. 1657 ◽  
Author(s):  
Norm Hall ◽  
Norm Hall ◽  
Chris Chubb ◽  
Chris Chubb
Keyword(s):  
Egg Production ◽  
Maximum Size ◽  
Management Control ◽  
Effective Control ◽  
Rock Lobster ◽  
The Status ◽  
Fishery Data ◽  
Age Structured ◽  
Panulirus Cygnus ◽  
Age Structured Model

In 1993, managers were concerned about the decline in the breeding stock of western rock lobster and introduced controls to raise egg production from the stock to those levels experienced in the late 1970s and early 1980s. The release of setose female lobsters (those with ovigerous setae) and of nonsetose female lobsters larger than a maximum legal size was required, the minimum legal carapace length (CL) was raised by 1 mm during the migratory phase between November and January, and the number of pots (traps) fished was reduced by 18%. Between 1993 and 1999, increases were observed in the indices of egg production obtained from research surveys and in the estimated released catches of setose female lobsters and of nonsetose female lobsters larger than the maximum size. From these and other fishery data, an age-structured model was developed to determine the status of the fishery and the effectiveness of each management control. By 1999, egg production of the stock had increased to 134% of the target level and 22% of the virgin level. Protection of setose female lobsters was the most effective control, followed by the reduction in pot usage, and then maximum legal size.

scholarly journals Interannual variation in the moult cycle and size at double breeding of mature female western rock lobster (Panulirus cygnus)

2006 ◽  
Vol 63 (9) ◽  
pp. 1631-1639 ◽  
Author(s):  
Simon de Lestang ◽  
Roy Melville-Smith
Keyword(s):  
Breeding Season ◽  
Western Australia ◽  
Interannual Variation ◽  
Carapace Width ◽  
Mature Female ◽  
Moult Cycle ◽  
Rock Lobster ◽  
Management Measures ◽  
Panulirus Cygnus

Abstract The moult cycle of mature female Panulirus cygnus was examined from data recorded over 32 years at four sites along the coast of Western Australia. A repeating trend for mature females was inferred from samples taken between 15 November and 15 August. Setae were present on the endopodites of all large females from June until February–March; between March and June the proportions of females with setae declined sharply as about 80% moulted into a non-setose phase. Females that did not undergo this moult in February remained setose throughout the “normal” non-setose period before moulting and producing a new set of setae by midwinter. New or eroded spermatophores were present on most large females between November and January, but their presence declined sharply during the February–March moult, to be absent by May. The percentage of mature females that bypassed the non-setose moult varied markedly from 1% to 40%, and was well correlated with mean water temperatures in January and February. The proportion that did not undergo a moult increased when these months were cool but decreased when they were warm. The size (carapace width) at which females carry two batches of eggs in one breeding season (double breeder) declined progressively from 96.6 mm to 84.1 mm with decreasing latitude (32°S to 28°S), and further declined at the offshore Abrolhos Islands (29°S) to 78.7 mm. The implications of these findings are discussed in relation to management measures designed to protect females in a setose condition.

Exploring the effects of spatial closures in a temperate marine ecosystem in Western Australia: A case study of the western rock lobster (Panulirus cygnus) fishery

2012 ◽  
Vol 245 ◽  
pp. 31-40 ◽  
Author(s):  
Hector M. Lozano-Montes ◽  
Russ Babcock ◽  
Neil R. Loneragan
Keyword(s):  
Western Australia ◽  
Marine Ecosystem ◽  
Rock Lobster ◽  
Panulirus Cygnus

Changes in lipid and fatty acid composition of late larval and puerulus stages of the spiny lobster (Panulirus cygnus) across the continental shelf of Western Australia

2006 ◽  
Vol 143 (2) ◽  
pp. 219-228 ◽  
Author(s):  
Bruce F. Phillips ◽  
Andrew G. Jeffs ◽  
Roy Melville-Smith ◽  
Chris F. Chubb ◽  
Matthew M. Nelson ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Continental Shelf ◽  
Acid Composition ◽  
Western Australia ◽  
Spiny Lobster ◽  
Panulirus Cygnus
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