1,147 research outputs found
Trends and transitions observed in an iconic recreational fishery across 140 years
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordRecreational fishing has taken place for centuries and is a globally popular activity, yet a lack of monitoring data means historical trends in recreational fisheries are often little understood compared to their commercial counterparts. We examined archival sources and conducted fisher interviews to examine changes in the Queensland recreational snapper (Chrysophrys auratus) fishery throughout its documented history. Over a 140-year period, we extracted data on technological innovations, catch rate trends, and social and regulatory change. Technological innovations were evident throughout the history of the recreational fishery. During the 1960s, 1990s and 2000s, several periods of rapid technological transition occurred, where a technology was adopted by >50% of recreational fishers within 10 years of its introduction. Since the 1960s, the timing and rate of adoption of fish-finding technology by recreational fishers has kept pace with the commercial sector. These technological advances have profoundly increased recreational targeting ability, but despite these advances, recalled recreational catch rate trends demonstrated significant declines over the course of the 20th century. While minimum size limits have been imposed on the snapper fishery for over a century, in contrast, the introduction of recreational in-possession limits only commenced in the 1990s. At this time, the beginnings of a societal transition was also observed, where longstanding âtake allâ attitudes towards fishing began to be replaced by a more conservation minded ethic. This shift was driven in part by the changing regulatory landscape, as well as wider attitudinal change influenced by the media and shifting societal norms, although whether this led to a reduction in total recreational catch remains unclear due to a lack of fishery-wide monitoring data and the open access nature of the recreational fishery. This study demonstrates that in the absence of systematic data collection, archival sources and fisher interviews can contribute an interdisciplinary knowledge base for understanding and interpreting historical fishery trends.RT, SB and JP were supported by the ARC Centre of Excellence for Coral Reef Studies. Fieldwork costs were supported by the University of Queenslandâs New Staff Start-Up Fund, awarded to RT, and the Fisheries Research Development Corporation (FRDC) on behalf of the Australian Government, report 2013-018 "Using commercial and recreational fisher knowledge to reconstruct historical catch rates for Queensland pink snapper (Pagrus auratus) and Spanish mackerel (Scomberomorus commerson): long-term data for incorporation into future stock assessmentsâ
Setting the Record Straight: Assessing the Reliability of Retrospective Accounts of Change
This is the final version of the article. Available from Wiley via the DOI in this record.Ecological degradation is accelerating, reducing our ability to detect and reverse declines. Resource user accounts have the potential to provide critical information on past change but their reliability can rarely be tested, hence they are often perceived as less valid than other forms of scientific data. We compared individual fishers' catch records, recorded 1-50 years ago, with their memories of past good, typical and poor catches for the corresponding time period. Good and poor catches were recalled with reasonable accuracy, matching variability in recorded catch with no significant change observed over time. Typical recalled catches were overestimated and became significantly more exaggerated over time, but were more comparable to mean than median recorded values. While accuracy of resource users' memory varied with the type of information recalled, our results suggest that carefully structured interview questions can produce reliable quantitative data to inform resource management, even after several decades have elapsed.All authors were supported by the Australian
Research Councilâs Centre for Excellence for Coral Reef
Studies. Fieldwork components were supported by The
University of Queenslandâs New Staff Start-Up Fund
(Project No. 2012000643) and the FRDC (Project No.
2013â018), on behalf of the Australian Government
Historical spatial reconstruction of a spawning-aggregation fishery
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Aggregations of individual animals that form for breeding purposes are a critical ecological processfor many species, yet these aggregations are inherently vulnerable to exploitation. Studies of the decline ofexploited populations that form breeding aggregations tend to focus on catch rate and thus often overlookreductions in geographic range. We tested the hypothesis that catch rate and site occupancy of exploited fish-spawning aggregations (FSAs) decline in synchrony over time. We used the Spanish mackerel (Scomberomoruscommerson) spawning-aggregation fishery in the Great Barrier Reef as a case study. Data were compiled fromhistorical newspaper archives, fisher knowledge, and contemporary fishery logbooks to reconstruct catchrates and exploitation trends from the inception of the fishery. Our fine-scale analysis of catch and effort dataspanned 103 years (1911â2013) and revealed a spatial expansion of fishing effort. Effort shifted offshore at arate of 9.4 nm/decade, and 2.9 newly targeted FSAs were reported/decade. Spatial expansion of effort maskedthe sequential exploitation, commercial extinction, and loss of 70% of exploited FSAs. After standardizing forimprovements in technological innovations, average catch rates declined by 90.5% from 1934 to 2011 (from119.4 to 11.41 fish/vessel/trip). Mean catch rate of Spanish mackerel and occupancy of exploited mackerelFSAs were not significantly related. Our study revealed a special kind of shifting spatial baseline in which acontraction in exploited FSAs occurred undetected. Knowledge of temporally and spatially explicit informationon FSAs can be relevant for the conservation and management of FSA species.S.B., R.T., andJ.P. were supported by the Australian Research Council(ARC) Centre of Excellence for Coral Reef Studies and the Fisheries Research and Development Corporation(project 2013-018). A.T. and S.B. were supported by funding from the Fisheries Research and Development Corporation (project 2010-007) on behalf of the Australian Government
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The theory of international business: the role of economic models
This paper reviews the scope for economic modelling in international business studies. It argues for multi-level theory based on classic internalisation theory. It present a systems approach that encompasses both firm-level and industry-level analysis
General analysis of signals with two leptons and missing energy at the Large Hadron Collider
A signal of two leptons and missing energy is challenging to analyze at the
Large Hadron Collider (LHC) since it offers only few kinematical handles. This
signature generally arises from pair production of heavy charged particles
which each decay into a lepton and a weakly interacting stable particle. Here
this class of processes is analyzed with minimal model assumptions by
considering all possible combinations of spin 0, 1/2 or 1, and of weak
iso-singlets, -doublets or -triplets for the new particles. Adding to existing
work on mass and spin measurements, two new variables for spin determination
and an asymmetry for the determination of the couplings of the new particles
are introduced. It is shown that these observables allow one to independently
determine the spin and the couplings of the new particles, except for a few
cases that turn out to be indistinguishable at the LHC. These findings are
corroborated by results of an alternative analysis strategy based on an
automated likelihood test.Comment: 18 pages, 3 figures, LaTe
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Decision-making in international business
This paper distinguishes three domains of international business theory: the boundaries of the multinational enterprise, the external environment of the enterprise and its internal structure. The central concern of internalisation theory is the boundaries of the firm. Any general theory of international business must analyse the external environment and internal structure as well. Competition dominates the external environment whilst co-operation dominates internal structure. Different models of decision-making are required for each. Different theories of decision-making must therefore be integrated in order to transform internalisation theory into a general theory of international business. This paper examines how this can be done
Clinical heterogeneity can hamper the diagnosis of patients with ZAP70 deficiency
One of the severe combined immunodeficiencies (SCIDs), which is caused by a genetic defect in the signal transduction pathways involved in T-cell activation, is the ZAP70 deficiency. Mutations in ZAP70 lead to both abnormal thymic development and defective T-cell receptor (TCR) signaling of peripheral T-cells. In contrast to the lymphopenia in most SCID patients, ZAP70-deficient patients have lymphocytosis, despite the selective absence of CD8+ T-cells. The clinical presentation is usually before 2 years of age with typical findings of SCID. Here, we present three new ZAP70-deficient patients who vary in their clinical presentation. One of the ZAP70-deficient patients presented as a classical SCID, the second patient presented as a healthy looking wheezy infant, whereas the third patient came to clinical attention for the eczematous skin lesions simulating atopic dermatitis with eosinophilia and elevated immunoglobulin E (IgE), similar to the Omenn syndrome. This study illustrates that awareness of the clinical heterogeneity of ZAP70 deficiency is of utmost importance for making a fast and accurate diagnosis, which will contribute to the improvement of the adequate treatment of this severe immunodeficiency
Flock size and structure influence reproductive success in four species of flamingo in 540 captive populations worldwide
This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: Anonymized data files for each species, and associated metadata, are available from https://doi.org/10.5281/zenodo.7504076. In line with the FAIR data principles, the data are made available under the following license: Creative Commons Attribution 4.0 International (CC BY 4.0).As global wildlife populations continue to decline, the health and sustainability of ex situ populations in zoos and aquariums have become increasingly important. However, the majority of managed ex situ populations are not meeting sustainability criteria and are not viable in the long term. Historically, ex situ flamingo (Phoenicopteriformes) populations have shown low rates of reproductive success and improvements are needed for long-term viability. Both flock size and environmental suitability have previously been shown to be important determinants of ex situ flamingo reproductive success in a limited number of sites in some species. Here we combined current and historic globally shared zoological records for four of the six extant species of flamingo (Phoeniconaias minor, Phoenicopterus chilensis, Phoenicopterus roseus, and Phoenicopterus ruber) to analyze how flock size, structure, and climatic variables have influenced reproductive success in ex situ flamingo populations at 540 zoological institutions from 1990 to 2019. Flock size had a strong nonlinear relationship with reproductive success for all species, with flock sizes of 41â100 birds necessary to achieve ca. 50% probability of reproduction. Additionally, an even sex ratio and the introduction of new individuals to a flock both increased ex situ reproductive success in some cases, while climatic variables played a limited role. We demonstrate the conservation management potential from globally shared zoological data and provide species-specific management recommendations to increase the reproductive success of global ex situ flamingo populations: minimum flock sizes should be increased, and we encourage greater collaboration between individual institutions and regional associations in exchanging birds between flocks.Irish Research CouncilInternational Max Planck Research School for Organismal Biolog
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