Locomotor Activity in the Western Rock Lobster, Panulirus longipes cygnus

1978 ◽  
Vol 29 (2) ◽  
pp. 169 ◽  
Author(s):  
GR Morgan
Keyword(s):  
Locomotor Activity ◽  
Individual Variation ◽  
Daily Variation ◽  
High Water ◽  
Peak Activity ◽  
High Water Temperature ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Catch Rates ◽  
Increasing Temperature

Daily locomotor activity rhythms in individual P. longipes cygnus were shown to be of a non- crepuscular nature with peak activity occurring immediately after the onset of darkness. Mean activity of animals in an intermoult stage increased with increasing temperature between 17 and 25�C but then declined, whilst for animals in a premoult stage there was no significant trend with temperature, activity rates remaining at a low level. Individual variation of response of intermoult animals also increased with temperature and is suggested as a contributing factor to high daily variation in commercial catch rates during months of high water temperature.

How reliable are the abundance indices derived from commercial catch–effort standardization?

2009 ◽  
Vol 66 (7) ◽  
pp. 1169-1178 ◽  
Author(s):  
Yimin Ye ◽  
Darren Dennis
Keyword(s):  
Generalized Linear Model ◽  
Observation Error ◽  
Potential Bias ◽  
Catch Per Unit Effort ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Abundance Indices ◽  
Catch Rates ◽  
Power Component ◽  
Stock Abundance

Commercial catch-per-unit-effort (CPUE) data are often standardized to construct indices of stock abundance. The value of such standardization lies in the improvement in the proportionality between the derived index and true abundance. Using the Torres Strait rock lobster ( Panulirus ornatus ) fishery in Australia as an example, we first standardized the commercial CPUE data using a generalized linear model (GLM) and then fitted observation error models to the resulting abundance indices and independent abundance data (as estimated by research diver surveys) to examine the proportionality. While the GLM standardization greatly improved proportionality in comparison with the nonstandardized commercial catch rates, it could produce biased results if the model did not explicitly incorporate variables that had caused changes in fishing efficiency. As most catch–effort standardizations do not model the fishing power component simultaneously, this result may serve as a warning to the potential bias in stock abundance indices extracted from GLMs that are underfitted.

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.

Environmental influences on daily commercial catch rates of South Australia's southern rock lobster (Jasus edwardsii)

2014 ◽  
Vol 23 (4) ◽  
pp. 362-374 ◽  
Author(s):  
John Feenstra ◽  
Richard McGarvey ◽  
Adrian Linnane ◽  
André E. Punt ◽  
Nigel Bean
Keyword(s):  
Environmental Influences ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Jasus Edwardsii ◽  
Catch Rates

Relationship between settlement of southern rock lobster pueruli, Jasus edwardsii, and recruitment to the fishery in Tasmania, Australia

2001 ◽  
Vol 52 (8) ◽  
pp. 1271 ◽  
Author(s):  
C. Gardner ◽  
S. D. Frusher ◽  
R. B. Kennedy ◽  
A. Cawthorn
Keyword(s):  
Interannual Variation ◽  
Stock Assessment ◽  
Catch Rate ◽  
Assessment Model ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Jasus Edwardsii ◽  
Catch Rates ◽  
Additional Support ◽  
Northeast Coast

Puerulus catches on artificial collectors were measured monthly at four sites around Tasmania from 1991 to April 2000, with the aim of predicting future changes in recruitment to the fishery. Support for the potential of catch-rate prediction in Tasmania was provided at the two sites that have overlap of several years between indices of puerulus settlement and indices of the abundance of recruits to the fishery. At Bicheno, on the northeast coast, correlations between annual puerulus index and commercial catch rates were highly significant, with a lag of 5 years (P< 0.01). Similar interannual trends in puerulus index and estimates from a stock-assessment model of the biomass of recruits to the fishery provided additional support for a link with puerulus index. A 5-fold interannual variation in puerulus index detected at Bicheno, with a peak in 1995, was preceded by 3 years of relatively low puerulus catch. The peak in puerulus index appears to lead to an increase in the abundance of sublegal males in research sampling 3 years later. Correlation between annual measures of puerulus index and catch rate also appeared significant at King Island (P= 0.06) although data at this site had less contrast.

Mass Appearance of Cyanobacterium Planktothrix rubescens in Lake Piaseczno, Poland

2003 ◽  
Vol 38 (1) ◽  
pp. 141-152 ◽  
Author(s):  
Danuta Krupa ◽  
Krzysztof Czernaś
Keyword(s):  
Dissolved Oxygen ◽  
Primary Production ◽  
Catchment Area ◽  
High Water ◽  
Water Bloom ◽  
High Water Temperature ◽  
Dissolved Oxygen Concentration ◽  
Planktothrix Rubescens ◽  
Assimilation Number ◽  
Bottom Zone

Abstract In 1989, Lake Piaseczno, Poland, exhibited a mass appearance of Planktothrix rubescens. During this time the pelagic and littoral areas exhibited significant increases in areal primary production (400 and 41 mg C m-2 h-1, respectively), chlorophyll α (100 and 6.9 mg m-2, respectively) and assimilation number (4 and 5.9 mg C m-2 h-1/mg chlα m-2, respectively). After the water bloom subsided, a reduction of dissolved oxygen concentration (down to 1.5 mg L-1) and high water temperature (10.2°C) in the offshore bottom zone was observed. While from 1991 to 1996, the primary production, chlorophyll α concentration and assimilation number values were decreasing, they were significantly higher than the values reported in 1986, prior to the mass cyanobacteria appearance. An indirect correlation with ion levels indicated that the outbreak of the cyanobacteria was linked with inflow of nutrients from the catchment area. The dramatic changes in the range and variability of the phytoplankton density indicate that the recent eutrophication of the lake has had profound effects on the structure and productivity of the aquatic community.

Effect of Temperature on Oil/Water Relative Permeabilities of Unconsolidated and Consolidated Sands

1985 ◽  
Vol 25 (06) ◽  
pp. 945-953 ◽  
Author(s):  
Mark A. Miller ◽  
H.J. Ramey
Keyword(s):  
Relative Permeability ◽  
Room Temperature ◽  
Water Saturation ◽  
High Water ◽  
Distilled Water ◽  
Relative Permeabilities ◽  
Two Phase ◽  
Dynamic Displacement ◽  
Irreducible Water Saturation ◽  
Increasing Temperature

Abstract Over the past 20 years, a number of studies have reported temperature effects on two-phase relative permeabilities in porous media. Some of the reported results, however, have been contradictory. Also, observed effects have not been explained in terms of fundamental properties known to govern two-phase flow. The purpose of this study was to attempt to isolate the fundamental properties affecting two-phase relative permeabilities at elevated temperatures. Laboratory dynamic-displacement relative permeability measurements were made on unconsolidated and consolidated sand cores with water and a refined white mineral oil. Experiments were run on 2-in. [5.1-cm] -diameter, 20-in. [52.-cm] -long cores from room temperature to 300F [149C]. Unlike previous researchers, we observed essentially no changes with temperature in either residual saturations or relative permeability relationships. We concluded that previous results may have been affected by viscous previous results may have been affected by viscous instabilities, capillary end effects, and/or difficulties in maintaining material balances. Introduction Interest in measuring relative permeabilities at elevated temperatures began in the 1960's with petroleum industry interest in thermal oil recovery. Early thermal oil recovery field operations (well heaters, steam injection, in-situ combustion) indicated oil flow rate increases far in excess of what was predicted by viscosity reductions resulting from heating. This suggested that temperature affects relative permeabilities. One of the early studies of temperature effects on relative permeabilities was presented by Edmondson, who performed dynamic displacement measurements with crude performed dynamic displacement measurements with crude and white oils and distilled water in Berea sandstone cores. Edmondson reported that residual oil saturations (ROS's) (at the end of 10 PV's of water injected) decreased with increasing temperature. Relative permeability ratios decreased with temperature at high water saturations but increased with temperature at low water saturations. A series of elevated-temperature, dynamic-displacement relative permeability measurements on clean quartz and "natural" unconsolidated sands were reported by Poston et al. Like Edmondson, Poston et al. reported a decrease in the "practical" ROS (at less than 1 % oil cut) as temperature increased. Poston et al. also reported an increase in irreducible water saturation. Although irreducible water saturations decreased with decreasing temperature, they did not revert to the original room temperature values. It was assumed that the cores became increasingly water-wet with an increase in both temperature and time; measured changes of the IFT and the contact angle with temperature increase, however, were not sufficient to explain observed effects. Davidson measured dynamic-displacement relative permeability ratios on a coarse sand and gravel core with permeability ratios on a coarse sand and gravel core with white oil displaced by distilled water, nitrogen, and superheated steam at temperatures up to 540F [282C]. Starting from irreducible water saturation, relative permeability ratio curves were similar to Edmondson's. permeability ratio curves were similar to Edmondson's. Starting from 100% oil saturation, however, the curves changed significantly only at low water saturations. A troublesome aspect of Davidson's work was that he used a hydrocarbon solvent to clean the core between experiments. No mention was made of any consideration of wettability changes, which could explain large increases in irreducible water saturations observed in some runs. Sinnokrot et al. followed Poston et al.'s suggestion of increasing water-wetness and performed water/oil capillary pressure measurements on consolidated sandstone and limestone cores from room temperature up to 325F [163C]. Sinnokrot et al confirmed that, for sandstones, irreducible water saturation appeared to increase with temperature. Capillary pressures increased with temperature, and the hysteresis between drainage and imbibition curves reduced to essentially zero at 300F [149C]. With limestone cores, however, irreducible water saturations remained constant with increase in temperature, as did capillary pressure curves. Weinbrandt et al. performed dynamic displacement experiments on small (0.24 to 0.49 cu in. [4 to 8 cm3] PV) consolidated Boise sandstone cores to 175F [75C] PV) consolidated Boise sandstone cores to 175F [75C] with distilled water and white oil. Oil relative permeabilities shifted toward high water saturations with permeabilities shifted toward high water saturations with increasing temperature, while water relative permeabilities exhibited little change. Weinbrandt et al. confirmed the findings of previous studies that irreducible water saturation increases and ROS decreases with increasing temperature. SPEJ P. 945

scholarly journals Female reproductive biology and spawning periodicity of two species of king prawns, Penaeus longistylus Kubo and Penaeus latisulcatus Kishinouye, form Queensland's East Coast Fishery

1988 ◽  
Vol 39 (6) ◽  
pp. 729 ◽  
Author(s):  
AJ Courtney ◽  
MCL Dredge
Keyword(s):  
Egg Production ◽  
East Coast ◽  
Sea Water ◽  
Coastal Region ◽  
Ovary Development ◽  
Commercial Catch ◽  
Ovary Weight ◽  
Species Population ◽  
Spawning Periodicity ◽  
Catch Rates

In the coastal region of central Queensland female red-spot king prawns, P. longistylus, and the western or blue-leg king prawns, P. latisulcatus, had high mean ovary weights and high proportions of advanced ovary development during the winter months of July and August of 1985 and 1986. On the basis of insemination, both species began copulating at the size of 26-27 mm CL, but P. longistylus matured and spawned at a smaller size than P. latisulcatus. Abundance of P. longistylus was generally three to four times greater than that of P. latisulcatus but the latter was subject to greater variation in abundance. Low mean ovary weight and low proportions of females with advanced ovaries were associated with the maximum mean bottom sea-water temperature (28.5�C) for both species. Population fecundity indices indicated that peaks in yolk or egg production (a) displayed a similar pattern for both species, (b) varied in timing from year to year for both species and (c) were strongly influenced by abundance. Generally, sample estimates of abundance and commercial catch rates (CPUE) showed similar trends. Differences between the two may have been due to changes in targeted commercial effort in this multi-species fishery.

Validity of using translucent zones of otoliths to age the pilchard Sardinops sagax neopilchardus from Albany, Western Australia

1996 ◽  
Vol 47 (4) ◽  
pp. 617 ◽  
Author(s):  
WJ Fletcher ◽  
SJ Blight
Keyword(s):  
Western Australia ◽  
Age Groups ◽  
Growth Curves ◽  
Relative Number ◽  
Older Individuals ◽  
Commercial Catch ◽  
Monthly Basis ◽  
Lower Accuracy ◽  
Sardinops Sagax ◽  
Catch Rates

Otoliths (sagittae) of the pilchard (Sardinops sagax neopilchardus) from the Albany region of Western Australia were examined on a monthly basis during 1989 to 1991. When read consecutively, with the month of capture known, a clear annual cycle of an increase in marginal increments to October followed by a decline was recorded. This pattern was, however, severely distorted when samples were re-examined after having been jumbled and the month of capture concealed. Younger age groups (≤3) showed evidence of multiple rings being formed annually, but not in all years or individuals, and this was not evident in older individuals (≥4). Agreement between readings was low (43-53%), especially between different readers. Resultant growth curves showed that males grow to a smaller size (L∞ =164, K = 0.805, Φ = 1.03) than females (L∞ = 174, K = 0.584, Φ= 0.95). Agreement between counts of annuli and ages estimated by using otolith weight and length was only 54% for all individuals, but increased to 76% for individuals assigned the same age by different readers. Given the poorer predictions of future catch rates from the relative number of 2-year-olds in the commercial catch using annuli (implying lower accuracy) and increased complexity in preparation, otolith weights will be the method adopted for future ageing.

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