scholarly journals Changes in Panulirus cygnus Settlement Along Western Australia Using a Long Time Series

2021 ◽  
Vol 8 ◽  
Author(s):  
Jessica Kolbusz ◽  
Simon de Lestang ◽  
Tim Langlois ◽  
Charitha Pattiaratchi
Keyword(s):  
Western Australia ◽  
Environmental Changes ◽  
Marine Invertebrate ◽  
Temporal Distribution ◽  
Second Phase ◽  
East Indian ◽  
Recruitment Failure ◽  
Starting Point ◽  
Before And After ◽  
Panulirus Cygnus

The pelagic development stages of many marine invertebrate species dictates their spatial and temporal distribution once reaching their benthic second phase of life. This life cycle is associated with the Western Rock Lobster (Panulirus cygnus) along the coast of Western Australia. Over the past 50 years, the number of puerulus reaching the nearshore reefs after their first 9 to 11 months of pelagic life in Western Australia has been monitored. These numbers, collected now at eight sites over the latitudes of the fishery, are indicative of the catchable stock 3–4 years into the future. In 2008, the fishery experienced a recruitment failure which lasted for several years before recovering to mean numbers pre-2008. This was associated with spatial and temporal shifts in the patterns of puerulus settlement. Previous research has hypothesized that physical and biological conditions in the south-east Indian Ocean no longer favored their survival. However, this decline has not been attributed to a single process. As the recovery is ongoing, contrasts in the settlement data before and after the decline are not completed. Here we characterize the data using ANOVA and pairwise comparisons to gain a better understanding of the typical patterns after the decline. Our results demonstrate that there has been a significant reduction in puerulus numbers over the first half of the season at all sites post decline. For the sites south of Lancelin there has been a significant reduction in puerulus numbers over the whole season. In addition, sites that show signs of recovery indicate that the majority of settlement occurred in the second half of the season. We anticipate these results to be the starting point for focused research into the environmental changes which may have occurred to generate these shifts in settlement numbers both from a timing and spatial perspective.

scholarly journals Using an oceanographic model to investigate the mystery of the missing puerulus

2021 ◽  
Author(s):  
Jessica Kolbusz ◽  
Tim Langlois ◽  
Charitha Pattiaratchi ◽  
Simon de Lestang
Keyword(s):  
Early Summer ◽  
Rock Lobster ◽  
East Indian ◽  
Leeuwin Current ◽  
Recruitment Failure ◽  
Pelagic Larvae ◽  
Consistent Increase ◽  
Panulirus Cygnus ◽  
Offshore Transport ◽  
Management Changes

Abstract. Dynamics of ocean boundary currents and associated shelf processes can influence onshore/offshore transport of water, critically impacting marine organisms that release long-lived pelagic larvae into the water column. The western rock lobster, Panulirus cygnus, endemic to Western Australia, is the basis of Australia's most valuable wild-caught commercial fishery. After hatching, western rock lobster larvae (phyllosoma) spend up to 11 months in offshore waters before ocean currents and their ability to swim, transport them back to the coast. The abundance of western rock lobster puerulus (settlement phase post phyllosoma) has historically been observed to be positively correlated with the strength of the Leeuwin Current, and an index of puerulus numbers is used by fisheries managers as a predictor of subsequent lobster abundance 3–4 years later. In 2008 and 2009 the Leeuwin Current was strong, yet a settlement failure occurred throughout the fishery prompting management changes and a rethinking of environmental factors associated with their settlement. Thus, understanding factors that may have been responsible for the settlement failure is important for fisheries management. Oceanographic parameters likely to influence puerulus settlement were derived for a 17 year period to investigate correlations. Analysis indicated that puerulus settlement at adjacent monitoring sites have similar oceanographic forcing with kinetic energy in the offshore and the strength of the Leeuwin Current being key factors. Settlement failure years were synonymous with “hiatus” conditions in the south-east Indian Ocean, and periods of sustained cooler water present offshore. Post 2009, there has been an unusual but consistent increase in the Leeuwin Current during the early summer months with a matching decrease in the Capes Current, that may explain an observed settlement timing mismatch compared to historical data. Our study has revealed that a culmination of these conditions likely led to the recruitment failure and subsequent changes in puerulus settlement patterns.

The Effect of a Period of Increased Legal Minimum Length of Sea Mullet in Westeren Australia

1950 ◽  
Vol 1 (2) ◽  
pp. 199 ◽  
Author(s):  
JM Thomson
Keyword(s):  
Western Australia ◽  
Environmental Changes ◽  
Minimum Length ◽  
Shark Bay ◽  
Bay Area ◽  
Before And After ◽  
Catch Statistics ◽  
Swan River

Following allegations of a depletionary trend in the mullet stocks a conservation scheme was initiated in Western Australia in 1942 by raising the legal minimum length in successive stages. In 1946 the legal length reverted to that in force before 1942. As far as can be seen from the catch statistics, the stocks did not benefit by the restriction period, the catches being of the same order before and after. It is possible that an increase in stocks occurred in the Shark Bay area, but as the fishery in this region was under-developed prior to the inception of the scheme there is no data to confirm such a supposition. The course of the Shark Bay fishery should be closely watched for any signs of overfishing now that the stocks are being more fully exploited. It would appear that no alteration in minimum lengths will effect an increase in the mullet stocks of the estuaries. There has been a definite decline in the mullet population of the Swan River since the early part of the century. This could be due to environmental changes rather than an effect of overfishing.

An Assessment of Environmental Changes in Three Lakes from King's County (Nova Scotia, Canada) Using Diatom-Based Paleolimnological Techniques

2008 ◽  
Vol 43 (2-3) ◽  
pp. 85-98 ◽  
Author(s):  
Joshua R. Thienpont ◽  
Brian K. Ginn ◽  
Brian F. Cumming ◽  
John P. Smol
Keyword(s):  
Nova Scotia ◽  
Environmental Changes ◽  
Sediment Cores ◽  
Lake Management ◽  
River System ◽  
210Pb Dating ◽  
Hydroelectric Power ◽  
Diatom Assemblages ◽  
Shoreline Development ◽  
Before And After

Abstract Paleolimnological approaches using sedimentary diatom assemblages were used to assess water quality changes over the last approximately 200 years in three lakes from King's County, Nova Scotia. In particular, the role of recent shoreline development in accelerating eutrophication in these systems was assessed. Sediment cores collected from each lake were analyzed for their diatom assemblages at approximately 5-year intervals, as determined by 210Pb dating. Analyses showed that each system has changed, but tracked different ecosystem changes. Tupper and George lakes recorded shifts, which are likely primarily related to climatic warming, with diatom assemblages changing from a preindustrial dominance by Aulacoseira spp. to present-day dominance by Cyclotella stelligera. In addition to the recent climatic-related changes, further diatom changes in the Tupper Lake core between approximately 1820 and 1970 were coincident with watershed disturbances (farming, forestry, and construction of hydroelectric power infrastructure). Black River Lake has recorded an increase in diatom-inferred total phosphorus since about 1950, likely due to impoundment of the Black River system for hydroelectric generation and subsequent changes in land runoff. Before-and-after (i.e., top-bottom) sediment analyses of six other lakes from King's County provided further evidence that the region is being influenced by climatic change (decreases in Aulacoseira spp., increases in planktonic diatom taxa), as well as showing other environmental stressors (e.g., acidification). However, we recorded no marked increase in diatom-inferred nutrient levels coincident with shoreline cottage development in any of the nine study lakes. Paleolimnological studies such as these allow lake managers to place the current limnological conditions into a long-term context, and thereby provide important background data for effective lake management.

scholarly journals Hazardous Drinking among Students over a Decade of University Policy Change: Controlled Before-and-After Evaluation

2018 ◽  
Vol 15 (10) ◽  
pp. 2137 ◽  
Author(s):  
Kypros Kypri ◽  
Brett Maclennan ◽  
Kimberly Cousins ◽  
Jennie Connor
Keyword(s):  
Environmental Changes ◽  
Population Policy ◽  
Code Of Conduct ◽  
Alcohol Policy ◽  
Absolute Difference ◽  
Effect Estimate ◽  
Policy Reforms ◽  
Student Body ◽  
University Policy ◽  
Before And After

Background: Responding to high levels of alcohol-related harm among students, a New Zealand university deployed a security and liaison service, strengthened the Student Code of Conduct, increased its input on the operation of alcohol outlets near campus, and banned alcohol advertising on campus. We estimated the change in the prevalence of alcohol consumption patterns among students at the university compared with other universities. Methods: We conducted a controlled before-and-after study with surveys in residential colleges at the target university in 2004 and 2014, and in random samples of students at the target university and three control universities in 2005 and 2013. The primary outcome was the prevalence of recent intoxication, while we analysed drinking per se and drinking in selected locations to investigate mechanisms of change. Results: The 7-day prevalence of intoxication decreased from 45% in 2004 to 33% in 2014 (absolute difference: 12%; 95% CI: 7% to 17%) among students living in residential colleges, and from 40% in 2005 to 26% in 2013 (absolute difference: 14%; 95% CI: 8% to 20%) in the wider student body of the intervention university. The intervention effect estimate, representing the change at the intervention university adjusted for change at other universities (aOR = 1.30; 95% CI: 0.89 to 1.90), was consistent with a benefit of intervention but was not statistically significant (p = 0.17). Conclusion: In this period of alcohol policy reform, drinking to intoxication decreased substantially in the targeted student population. Policy reforms and coincidental environmental changes may each have contributed to these reductions.

scholarly journals A network-based approach to deciphering a dynamic microbiome’s response to a subtle perturbation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Grace Tzun-Wen Shaw ◽  
An-Chi Liu ◽  
Chieh-Yin Weng ◽  
Yi-Chun Chen ◽  
Cheng-Yu Chen ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Ecosystem Functioning ◽  
Environmental Changes ◽  
Ecosystem Dynamics ◽  
Environmental Research ◽  
Human Society ◽  
The Past ◽  
Environmental Perturbations ◽  
Before And After ◽  
Occurrence Patterns

Abstract Over the past decades, one main issue that has emerged in ecological and environmental research is how losses in biodiversity influence ecosystem dynamics and functioning, and consequently human society. Although biodiversity is a common indicator of ecosystem functioning, it is difficult to measure biodiversity in microbial communities exposed to subtle or chronic environmental perturbations. Consequently, there is a need for alternative bioindicators to detect, measure, and monitor gradual changes in microbial communities against these slight, chronic, and continuous perturbations. In this study, microbial networks before and after subtle perturbations by adding S. acidaminiphila showed diverse topological niches and 4-node motifs in which microbes with co-occurrence patterns played the central roles in regulating and adjusting the intertwined relationships among microorganisms in response to the subtle environmental changes. This study demonstrates that microbial networks are a good bioindicator for chronic perturbation and should be applied in a variety of ecological investigations.

scholarly journals Aras Valley (northwest Iran): high-resolution stratigraphy of a continuous central Tethyan Permian–Triassic boundary section

Fossil Record ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 33-69 ◽  
Author(s):  
Jana Gliwa ◽  
Abbas Ghaderi ◽  
Lucyna Leda ◽  
Martin Schobben ◽  
Sara Tomás ◽  
...  
Keyword(s):  
High Resolution ◽  
Carbon Isotopes ◽  
Environmental Changes ◽  
Triassic Boundary ◽  
Nw Iran ◽  
Environmental Setting ◽  
Before And After ◽  
Permian Extinction ◽  
Permian Mass Extinction ◽  
Permian Triassic Boundary

Abstract. The Permian–Triassic boundary section in the Aras Valley in NW Iran is investigated with respect to carbonate microfacies, biostratigraphy (particularly conodonts, nautiloids, and ammonoids), chemostratigraphy (carbon isotopes), and environmental setting. Correlation of the data allows the establishment of a high-resolution stratigraphy based on conodonts (with four Wuchiapingian, 10 Changhsingian, and three Griesbachian zones), ammonoids (with nine Changhsingian zones), and carbon isotopes; it forms the base for the reconstruction of the environmental changes before and after the end-Permian extinction event at the studied locality. In the Aras Valley section, there is no evidence for the development of anoxic conditions, associated with the end-Permian mass extinction.

scholarly journals Biphasic pattern in the effect of severe measles infection; the difference between additive and multiplicative scale

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nhat Thanh Hoang Le ◽  
Nhan Thi Ho ◽  
Bryan Grenfell ◽  
Stephen Baker ◽  
Ronald B. Geskus
Keyword(s):  
Infectious Diseases ◽  
Hospital Admission ◽  
Measles Virus ◽  
Hospital Admissions ◽  
Admission Rate ◽  
Second Phase ◽  
Before And After ◽  
The Difference ◽  
Two Phases ◽  
Additive Scale

Abstract Background Infection with measles virus (MeV) causes immunosuppression and increased susceptibility to other infectious diseases. Only few studies reported a duration of immunosuppression, with varying results. We investigated the effect of immunosuppression on the incidence of hospital admissions for infectious diseases in Vietnamese children. Methods We used retrospective data (2005 to 2015; N = 4419) from the two pediatric hospitals in Ho Chi Minh City, Vietnam. We compared the age-specific incidence of hospital admission for infectious diseases before and after hospitalization for measles. We fitted a Poisson regression model that included gender, current age, and time since measles to obtain a multiplicative effect measure. Estimates were transformed to the additive scale. Results We observed two phases in the incidence of hospital admission after measles. The first phase started with a fourfold increased rate of admissions during the first month after measles, dropping to a level quite comparable to children of the same age before measles. In the second phase, lasting until at least 6 years after measles, the admission rate decreased further, with values up to 20 times lower than in children of the same age before measles. However, on the additive scale the effect size in the second phase was much smaller than in the first phase. Conclusion The first phase highlights the public health benefits of measles vaccination by preventing measles and immune amnesia. The beneficial second phase is interesting, but its strength strongly depends on the scale. It suggests a complicated interaction between MeV infection and the host immunity.

Feral pigs in north-western Australia: population recovery after 1080 baiting and further control

2006 ◽  
Vol 33 (5) ◽  
pp. 417 ◽  
Author(s):  
Laurie E. Twigg ◽  
Tim Lowe ◽  
Michael Everett ◽  
Gary Martin
Keyword(s):  
Western Australia ◽  
Population Recovery ◽  
Feral Pigs ◽  
Muddy Water ◽  
Good Body Condition ◽  
Bait Station ◽  
Before And After ◽  
Bait Stations ◽  
North Western ◽  
Fitzroy River

The recovery rate of a population of feral pigs (Sus scrofa) in the west Kimberley in north-western Australia was determined 12 months after a 1080 (sodium fluoroacetate)-baiting program. An estimated 56 pigs were present in the 15 000-ha study area in August 2005 compared with the prebaiting levels of 250–275 pigs in 2004 (11 pigs were known to be alive on site after the 2004 baiting). This represents a population recovery of 20–23% of the 2004 prebaiting levels. Although most pigs were in good body condition, environmental conditions were quite different between the two years. In 2005, some waterholes were dry or comprised mainly muddy water with little associated shelter for feral pigs. Consequently, and in contrast to 2004, no pigs were seen, and no bait take could be attributed to feral pigs, at the four resurveyed waterholes. Most pig sightings, and activity, were close to the Fitzroy River. Fermented wheat, with blood and bone, was used to determine areas of pig activity, and also used as prefeed before 1080-baiting commenced in 2005. Using the same bait stations as for 2004, plus additional stations established in new areas of pig activity, 1080-treated wheat and malted barley again proved highly effective in reducing pig numbers. The daily sighting index before and after 1080-baiting indicated that pig numbers had been reduced by ~90% within four days. Estimated pre- and postpoisoning density, with and without an edge effect, was 0.12–1.7 pigs km–2 and 0.05–0.67 pigs km–2. Pig tracks decreased to zero on the six track plots within two days of baiting, but the number of macropod tracks remained constant over the four-day baiting period. Thirty-eight poisoned pigs were found after 1080-baiting, and these were generally in clustered groups within 200 m of an active bait station. Poisoned juvenile pigs were again found closer to the active bait stations than were adult or subadult pigs (P < 0.05).

scholarly journals Diverging from News Media: An Exploratory Study on the Changing Dynamics between Media and Public Attention on Cancer in China from 2011-2020

2021 ◽  
Author(s):  
Yangkun Huang ◽  
Xiaoping Xu ◽  
Sini Su
Keyword(s):  
News Media ◽  
Media Coverage ◽  
Cancer Information ◽  
Second Phase ◽  
Media Industry ◽  
Public Attention ◽  
Media Attention ◽  
Starting Point ◽  
The Media ◽  
Cancer Types

Over the past decade, China has witnessed fast-paced technological advancements in the media industry, as well as major shifts in the health agenda portrayed in the media. Therefore, a key starting point when discussing health communication lies in whether media attention and public attention towards health issues are structurally aligned, and to what extent the news media guide public attention. Based on data mined from 73,060 sets of the Baidu Search Index and Media Index on 20 terms covering different types of cancer from 2011 to 2020, the Granger test demonstrates that, in the last decade, public attention and media attention towards cancer in China has gone through two distinct phases. During the first phase, 2011-2015, Chinese news media still held the key in transferring the salience of issues on most cancer types to the public. In the second phase, from 2016-2020, public attention towards cancer has gradually diverged from media coverage, mirroring the imbalance and mismatch between the demand of active public and the supply of cancer information from news media. This study provides an overview of the dynamic transition on cancer issues in China over a ten-year span, along with descriptive results on public and media attention towards specific cancer types.

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