scholarly journals Hard to Manage? Dynamics of Soft-Shell Crab in the Newfoundland and Labrador Snow Crab Fishery

2021 ◽  
Vol 8 ◽  
Author(s):  
Darrell R.J. Mullowney ◽  
Krista D. Baker ◽  
Julia R. Pantin
Keyword(s):  
Newfoundland And Labrador ◽  
Best Practice ◽  
Early Spring ◽  
Warm Water ◽  
Practice Management ◽  
Optimal Time ◽  
Snow Crab ◽  
Harvest Rate ◽  
Soft Shell ◽  
June July

Capture of recently molted soft-shell crab in the Newfoundland and Labrador (NL) snow crab (Chionoecetes opilio) fishery is undesirable due to resource wastage associated with low meat yield and supposed high mortality rates upon discard. This study is intended to formalize best-practice management advice for avoidance of soft-shell crab in the fishery. The study investigates factors affecting soft-shell incidence in the catch across a large geographic stock range encompassing dynamic habitat and contrasting harvest rate strategies. The results demonstrate an interaction between seasonality and harvest rate in governing soft-shell crab levels in the fishery. Greatest potential for high soft-shell incidence occurs in late-spring or summer (June–July) fisheries in warm water populations subjected to heavy fishing pressure, with warm water populations shown to be associated with earlier molting periods. The study concludes that the optimal time to harvest snow crab is during winter or early spring, and advises that wherever winter or early spring fisheries are not possible, a best-practice management strategy is to minimize wastage by maintaining a strong residual biomass of large hard-shell males in the population at all times. This strategy is easily enabled by consistent application of low exploitation rates.

scholarly journals Size-at-maturity shift in a male-only fishery: factors affecting molt-type outcomes in Newfoundland and Labrador snow crab (Chionoecetes opilio)

2020 ◽  
Author(s):  
Darrell R J Mullowney ◽  
Krista D Baker
Keyword(s):  
Population Density ◽  
Newfoundland And Labrador ◽  
Cold Water ◽  
Large Male ◽  
Snow Crab ◽  
Size At Maturity ◽  
Chionoecetes Opilio ◽  
Factors Affecting ◽  
Male Density ◽  
Process Factors

Abstract A sex-asymmetric downward shift in size-at-terminal-molt has recently occurred in males in some portions of the Newfoundland and Labrador (NL) snow crab stock range, a first known occurrence for such processes in snow crab (Chionoecetes opilio) stocks. This study examines plausible factors promoting the shift in size-at-terminal-molt [synonymous with size-at-maturity (SaM)] including individual size, temperature, population density, and sex ratio. Analyses highlight expanse of cold water and large male density as being significant predictors of molt-type outcomes. A confluence of cold conditions and low density of large males promoted the SaM shift. In turn, the low male density was associated with recently elevated fishery exploitation rates under quota-controlled management. It remains unknown the extent to which the reduction in terminal size reflects a phenotypic vs. genotypic process. Factors affecting skip-molting in male snow crab are investigated, and we find that skip-molting occurs most frequently under extreme cold and high population density conditions. Potential complications arising from altered growth dynamics are discussed. Overall, the results advance knowledge on intraspecific competition processes within snow crab populations and inform fisheries management systems that male-only harvest strategies do not provide full protection from biological harm to aquatic resources through fishing.

scholarly journals Improving Outcomes Through Principles of Best Practice Management: Australia's National Lung Cancer Framework

2018 ◽  
Vol 4 (Supplement 2) ◽  
pp. 243s-243s
Author(s):  
B. Daveson ◽  
V. Milch ◽  
J. Chynoweth ◽  
L. Kable ◽  
M. Austen ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cancer Care ◽  
Best Practice ◽  
Cancer Control ◽  
Communication Strategy ◽  
Practice Management ◽  
System Level ◽  
Local Context ◽  
Evidence Based ◽  
National Implementation

Background and context: Lung cancer is estimated to be the fifth most commonly diagnosed cancer and leading cause of cancer death in Australia, representing 9.2% of all new cancer cases (n = 138,321) diagnosed and 18.9% of all cancer deaths (n = 48,586). The 5-year survival rate for those with lung cancer is 16%, compared with 68% for all cancers combined (between 2009 and 2013). Lung cancer is also the leading cause of cancer burden in Australia and patients affected by lung cancer may experience high levels of unmet need with associated psychological distress and decreased quality of life. Cancer Australia, Australia's national cancer control agency, developed the national Lung Cancer Framework: Principles for Best Practice Lung Cancer Care (Framework) to provide evidence-based, best practice information, strategies, tools and resources to support local adoption of the 5 principles for best practice management of lung cancer (principles): patient-centered care; multidisciplinary care; timely access to evidence-based care; coordination, communication and continuity of care; and data-driven improvements. Aim: The framework aims to improve the outcomes and experiences of people affected by lung cancer in Australia by supporting national uptake of the principles. Strategy/Tactics: Cancer Australia: • established a Lung Cancer Advisory Group to advise on strategies for national implementation of the framework and its principles • conducted a national lung cancer demonstration project, with advice from an Expert Steering Group, to demonstrate the delivery of lung cancer care according to the principles across a range of service delivery settings, and identify key factors contributing to ongoing delivery of best practice cancer care • completed systematic reviews for each principle to determine the effectiveness of the principles in improving lung cancer care processes and outcomes. Program/Policy process: To support national adoption of the framework and its principles, Cancer Australia: • developed a promotion and communication strategy for widespread national dissemination • convened a National Summit to bring together policy makers, clinical stakeholders and consumers to support local application of the principles, and drive optimal care for people affected by lung cancer • identified and communicated consumer, service, and system-level approaches to aid sustainable use of the principles. Outcomes: The evidence-based approach to the development of the framework and its principles identified ways to improve the healthcare system to achieve better outcomes for those affected by lung cancer in Australia. A coordinated approach to the delivery of the National Summit supported those involved in lung cancer care to share and adopt innovative and multilevel strategies for best practice care. What was learned: Embedding strategies to support implementation of the principles, responsive to local context, was key to enabling sustainable improvements in national lung cancer control.

scholarly journals Evaluation of optimal time and parameters for measuring potentially mineralized nitrogen in soil

2008 ◽  
pp. 41-49
Author(s):  
Mirjana Kresovic ◽  
Vlado Licina ◽  
Svetlana Antic-Mladenovic
Keyword(s):  
Early Spring ◽  
Optimal Time ◽  
Soil Parameters ◽  
Anaerobic Incubation ◽  
Aerobic Incubation ◽  
Brown Forest Soil ◽  
Controlled Conditions ◽  
Long Term Experiments ◽  
Aerobic And Anaerobic

Our research was done on brown forest soil with long-term experiments and with a system of fertilizing which is in use for 40 years. Experiment variants with an increasing dose of nitrogen fertilizer were chosen for this research. Two experiments have been performed: experiment in pots supplied with ammonium nitrate labeled with a stable isotope 15N (11.8%) and experiment in the field. The aim of the research was to establish which plant and soil parameters group (obtained in the controlled conditions and/or in the field) could be considered as reliable for evaluation of aerobic and anaerobic incubation and of the best time for estimation of potentially mineralized nitrogen in soil. According to the determined correlative dependence, it could be concluded that reliability of aerobic incubation should be estimated in October by plant and soil parameters from field, anaerobic incubation should be estimated in early spring (March) by plant and soil parameters, from controlled conditions (pots) and from field.

Comparison of reference points estimated using a size-based method for two high-latitude crab species in the United States and Canada

2004 ◽  
Vol 61 (8) ◽  
pp. 1404-1430 ◽  
Author(s):  
M SM Siddeek ◽  
Bernard Sainte-Marie ◽  
Jim Boutillier ◽  
Gretchen Bishop
Keyword(s):  
United States ◽  
High Latitude ◽  
The United States ◽  
Reference Points ◽  
Minimum Size ◽  
Snow Crab ◽  
Harvest Rate ◽  
Stock Recruitment ◽  
Dungeness Crabs ◽  
Spawning Biomass

We briefly reviewed the decision rules currently used for managing two major high-latitude crab stocks, snow crab (Chionoecetes opilio) and Dungeness crab (Cancer magister), in the United States and Canada and compared them with model-based reference points, harvest rate, and biomass proportion relative to virgin biomass, developed using species- and area-specific parameters. The model followed a size-based approach, which incorporated Beverton–Holt and Ricker stock–recruitment models and estimated mean and median reference points. The recruitment was also perturbed to generate distributions of reference points. The Beverton–Holt stock–recruitment model provided a lower harvest rate than that of the Ricker model. Harvest rates were lower for combined sexes spawning biomass than for female-only spawning biomass. Increasing the minimum size at first capture and decreasing the handling mortality resulted in increased harvest rates. Changes in fishery duration and timing of fishery open date did not change the harvest rate appreciably. The harvest rates for the Canadian snow and Dungeness crabs were mostly higher than those estimated for the Bering Sea and Southeast Alaska stocks. Reliable estimates of a number of life history parameters are lacking for both species, and hence, the results of this exercise need to be treated in a precautionary manner.

Out-of-Season Breeding in Adult Suffolk Ewes following Light and Melatonin Treatment

1987 ◽  
Vol 1987 ◽  
pp. 88-88
Author(s):  
Sandra J. Ward ◽  
H.LI. Williams
Keyword(s):  
Effective Means ◽  
Reproductive Activity ◽  
Early Spring ◽  
Light Treatment ◽  
Short Term ◽  
Melatonin Treatment ◽  
June July ◽  
Conventional Type

Photostimulation is an effective means of manipulating reproductive activity in most British breeds of sheep. Short term light treatment can initiate oestrus cycles during June/July and thus provides the opportunity for autumn lambing (Williams, 1977). The most effective light treatments comprise a period of supplementary light followed by a period of long nights which requires controlled environmental housing. Recent investigations have demonstrated that melatonin treatment may replace the long night phase thus simplifying management (Williams, 1985). Attempts to dispense with the period of supplementary light by transferring Spring lambing Welsh Mountain ewes abruptly to long nights during early Spring were not as successful as the conventional type of light treatment (Williams, 1967). This investigation was undertaken to compare the response of adult Suffolk crossbred ewes given melatonin in the Spring with or without a priming period of supplementary light.

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