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.

Manufacturer’s Entry in the Product-Sharing Market

2021 ◽  
Author(s):  
Lin Tian ◽  
Baojun Jiang ◽  
Yifan Xu
Keyword(s):  
Transaction Cost ◽  
Mobile Communications ◽  
Marginal Cost ◽  
Large Scale ◽  
Economic Benefits ◽  
Problem Definition ◽  
Environmental Benefits ◽  
Economic Implications ◽  
Cost Of Production ◽  
The Impact

Problem definition: Mobile communications technologies and online platforms have enabled large-scale consumer-to-consumer (C2C) sharing of their underutilized products. This paper studies a manufacturer’s optimal entry strategy in the product-sharing market and the economic implications of its entry. Academic/practical relevance: Sharing of products or services among consumers has experienced dramatic growth in recent years. The impact of C2C sharing on traditional firms can be very significant. In response to C2C product sharing, many manufacturers (e.g., General Motors and BMW) have entered the product-sharing market to provide business-to-consumer (B2C) rental services in addition to outright sales to consumers. Methodology: We employ a game-theoretic analytical model for our analysis. Results: Our analysis shows that when C2C sharing has a low transaction cost and the manufacturer’s marginal cost of production is not very high, the manufacturer will find it not optimal to offer its own rental services to consumers. In contrast, when the C2C sharing transaction cost is high or the manufacturer’s marginal cost of production is high, the manufacturer should offer enough units of the products for rental to squeeze out C2C sharing (in expectation). When the C2C-sharing transaction cost and the manufacturer’s marginal cost are both in the middle ranges, the manufacturer’s rental services and the C2C sharing will coexist, in which case the manufacturer’s entry in the sharing market may reduce the total number of units of the product in the whole market, but increase the consumer surplus and the social welfare. This reduced number of products due to the manufacturer’s B2C rental service also suggests less environmental impact from production. Managerial implications: The production cost and the C2C sharing transaction cost play critical roles in determining the manufacturer’s optimal quantity to use for its B2C rental services and the equilibrium outcome. In some situations, the manufacturer’s entry in the sharing market provides not only economic benefits to the firm and consumers, but also environmental benefits to the society as a whole.

Challenges for Diadromous Fishes in a Dynamic Global Environment

2009 ◽  
Keyword(s):  
Chinook Salmon ◽  
Large Scale ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Commercial Catch ◽  
Atmospheric Processes ◽  
Energy Transfers ◽  
Salmon Production ◽  
The Impact

<em>Abstract</em>.-Pacific salmon <em>Oncorhynchus </em>spp. catches are at historic high levels. It is significant that one of the world's major fisheries for a group of species that dominates the surface waters of the subarctic Pacific is actually very healthy. Natural trends in climate are now recognized to cause large fluctuations in Pacific salmon production, as shown in historical records of catch and recent changes probably have been affected by greenhouse gas induced climate changes. Pink salmon <em>O. gorbuscha </em>and chum salmon <em>O. keta </em>production and catch has increased in the past 30 years and may continue in a similar trend for for the next few decades. Coho salmon <em>O. kisutch </em>and Chinook salmon <em>O. tshawytscha </em>catches have been declining for several decades, particularly at the southern end of their range, and they may continue to decline. In the 1970s, hatcheries were considered to be a method of adding to the wild production of coho and Chinook salmon because the ocean capacity to produce these species was assumed to be underutilized. Large-scale changes in Pacific salmon abundances are linked to changes in large-scale atmospheric processes. These large-scale atmospheric processes are also linked to planetary energy transfers, and there is a decadal scale pattern to these relationships. Pacific salmon production in general is higher in decades of intense Aleutian lows than in periods of weak Aleutian lows. Key to understanding the impact of climate change on Pacific salmon is understanding how the Aleutian low will change. Chinook and coho salmon are minor species in the total commercial catch, but important socially and economically in North America. A wise use of hatcheries may be needed to maintain abundances of these species in future decades.

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 Identifying indicators of the effects of fishing using alternative models, uncertainty, and aggregation error

2011 ◽  
Vol 68 (7) ◽  
pp. 1417-1425 ◽  
Author(s):  
Sarah J. Metcalf ◽  
Matthew B. Pember ◽  
Lynda M. Bellchambers
Keyword(s):  
Economic Value ◽  
Ecosystem Change ◽  
Small Fish ◽  
Rock Lobster ◽  
Commercial Catch ◽  
Alternative Models ◽  
Qualitative Models ◽  
Lobster Fishery ◽  
Panulirus Cygnus

Abstract Metcalf, S. J., Pember, M. B., and Bellchambers, L. M. 2011. Identifying indicators of the effects of fishing using alternative models, uncertainty, and aggregation error. – ICES Journal of Marine Science, 68: 1417–1425. The identification of indicators of the indirect effects of fishing is often an issue for fisheries management, particularly if just commercial catch data are available. Complex, intermediate, and simplified qualitative models were produced for a fishery case study off Western Australia to identify potential indicators of ecosystem change attributable to western rock lobster (Panulirus cygnus) extraction and bait input. Models of intermediate complexity were used to identify indicators because they produced the least aggregation error. Structural uncertainty was considered through a series of structurally different intermediate models. These alternate models consistently predicted that extraction of rock lobster may positively impact small fish of low economic value, such as old wife (Enoplosus armatus), footballer sweep (Neatypus obliquus), and king wrasse (Coris auricularis). These small fish were therefore identified as potential indicators of the effects of rock lobster extraction. Small crustaceans (amphipods and isopods) also displayed positive impacts attributable to bait input from the rock lobster fishery and were identified as potential indicators of bait effects. Monitoring of these indicators may aid the detection of ecosystem change caused by the rock lobster fishery.

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

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.

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.

scholarly journals Eco-Efficiency Assessment of the Application of Large-Scale Rechargeable Batteries in a Coal-Fired Power Plant

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1384 ◽  
Author(s):  
Piotr Krawczyk ◽  
Anna Śliwińska
Keyword(s):  
Power Plant ◽  
Large Scale ◽  
Fossil Fuels ◽  
Economic Benefits ◽  
Fuel Oil ◽  
Electricity Production ◽  
Hard Coal ◽  
Heavy Fuel Oil ◽  
Efficiency Assessment ◽  
The Impact

This article presents the results of an eco-efficiency assessment of the application of large-scale rechargeable battery technology in electricity generation from coal. The eco-efficiency of electricity production in a 350 MW coal-fired power plant was calculated. Two production variants were compared: with the use of a lithium-ion battery of a 400 MWh capacity to optimize the operation of power blocks and without using the battery. Hard coal is one of the main fossil fuels used to generate electricity in Poland. Despite the growing share of electricity from renewable sources, this situation will persist for many more years. The main reasons for this are the high costs and long-lasting process of moving away from fossil fuels in the energy sector. Therefore, any technical solutions that can temporarily reduce the negative impact of coal-based power engineering on the environment should be considered. At the same time, the economic aspects of such solutions must be taken into account. That is why the eco-efficiency assessment method was chosen, which integrates economic and environmental aspects. The obtained results of the analyses indicate the occurrence of environmental and economic benefits resulting from the use of the battery in coal-fired power plants. It has been found that battery-based technology is more eco-efficient than technology without such a battery. A sensitivity analysis was carried out, which allowed the impact of individual computational variables on the eco-efficiency assessment result to be assessed. The results indicate that fuel prices (coal and heavy fuel oil—mazout) and CO2 emission allowances have the greatest impact on the eco-efficiency of the analyzed technology. It was also found that the factors related to the battery, such as its efficiency, life span, decrease of the capacity after 10 years of operation, and construction cost, have a much smaller impact on the results.

Spatial and temporal distribution of early-stage phyllosoma of westren rock lobster, Panulirus cygnus

1980 ◽  
Vol 31 (4) ◽  
pp. 485 ◽  
Author(s):  
DW Rimmer
Keyword(s):  
Early Stage ◽  
Temporal Distribution ◽  
Lunar Cycle ◽  
Stage I ◽  
Western Coast ◽  
Spatial And Temporal Distribution ◽  
Rock Lobster ◽  
Larval Release ◽  
Panulirus Cygnus ◽  
The Impact

Time-series sampling for early-stage phyllosoma of P. cygnus was carried out off the western coast of Australia near the centre of the population of breeding adults. Hatching occurred from November through February in 1973-74 and 1974-75. Spatial distribution of the larvae was similar between the two seasons studied. The density of newly hatched (stage I) phyllosoma was greatest along the off-shore portion of the continental shelf. The majority of larvae moved off shore soon after hatching and the relative abundance of stages 11 and 111 increased with distance off shore. An off-shore extension of the sampling yielded an estimated minimum net rate of off-shore transport of 5.25 km,day for the stage I phyllosoma taken at the station farthest off shore. In 1973-74. larval release increased gradually from a low level in November to a peak in mid January. In 1974-75 larval release commenced at least a month earlier and peaked in late November, tapered off through December, and peaked again in mid January. Water temperature correlated with temporal differences in larval release. Warmer temperatures early in the 1974-75 season apparently induced the onset of breeding early enough to permit a second breeding by some females. There appeared to be no periodicity of hatching related to the lunar cycle. The distribution of early-stage phyllosoma was patchy and the impact of patchiness on quantitative sampling is discussed.

Delay-difference model to estimate the catch of different categories of the western rock lobster (Panulirus cygnus) for the two stages of the annual fishing season

1997 ◽  
Vol 48 (8) ◽  
pp. 949 ◽  
Author(s):  
Norman G. Hall
Keyword(s):  
Management Strategies ◽  
Fishing Effort ◽  
Rock Lobster ◽  
Fishing Season ◽  
Limited Entry ◽  
Harvest Strategy ◽  
Panulirus Cygnus ◽  
Two Stages ◽  
The Impact ◽  
Delay Difference

The annual exploitation rate of the limited-entry rock lobster fishery of Western Australia is controlled by constraining the total allowable effort. An important aspect of the harvest strategy introduced in 1993 was the use of annual levels of allowed fishing effort that could be varied in accordance with predicted levels of recruitment to the fishery in order to increase the abundance of spawning females and to reduce the variability in the level of annual catch. A model was needed that could examine the impact of alternative management strategies on the catches both within and between fishing seasons. The model that has been developed uses a delay-difference structure in which the fishing season is divided into two periods. Growth between the periods, and over the closed fishing season, is determined from tagging data. Recruitment is estimated from the observed levels of puerulus settlement. The model has been fitted to the observed effort within the southern sector of the fishery. This model allows the evaluation of alternative levels of fishing effort within the management zone, providing managers and industry with a tool to explore alternative harvest strategies.

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