Systematic assessment of the reliability of quantitative PCR assays targeting IS900 for the detection of Mycobacterium avium ssp. paratuberculosis presence in animal and environmental samples.

Mycobacterium avium ssp. paratuberculosis (MAP) is the bacterium responsible for causing Johne's Disease (JD), which is endemic to dairy cattle and also incriminated in the etiology of Crohn's disease. The difficulty in diagnosing asymptomatic cows for JD makes this disease hard to control. JD is considered a priority under the One Health approach to prevent the spread of the causative agent to humans. Environmental screening is a strategic approach aimed at identifying dairy herds with animals infected with MAP. It serves as the initial step toward implementing more intensive actions to control the disease. Quantitative polymerase chain reaction (qPCR) technology is widely used for diagnosis. Given that genome sequencing is now much more accessible than ever before, it is possible to target regions of the MAP genome that allow for the greatest diagnostic sensitivity and specificity. The aim of this study was to identify among the published qPCR assays targeting IS900 the more cost-effective options to detect MAP and to validate them in the diagnostic context of JD disease. MAP IS900 is a prime target because it is a multicopy genetic element. A total of 136 publications have reported on the use of IS900 qPCR assays over the past 3 decades. Among these records, 29 used the SYBR Green chemistry and TaqMan technology was used in 107 reports. Aside from the 9 reports using commercial assays, 72 TaqMan reports cited previously published work, leaving us with 27 TaqMan qPCR designs. Upon closer examination, 5 TaqMan designs contained mismatches in primer or probe sequences. Additionally, others exhibited high similarity to environmental microorganisms or non-MAP mycobacteria. We assessed the performance of 6 IS900 qPCR designs and their sensitivity when applied to clinical or environmental samples, which varied from 4 to 56 fold overall. Additionally, we provide recommendations for testing clinical and environmental samples, as certain strategies used previously should be avoided due to poor qPCR design (e.g., the presence of mismatches) or a lack of specificity.

Identification, validation and biological characterisation of novel glioblastoma tumour microenvironment subtypes: implications for precision immunotherapy.

BACKGROUND: New precision medicine therapies are urgently required for glioblastoma (GBM). However, to date, efforts to subtype patients based on molecular profiles have failed to direct treatment strategies. We hypothesised that interrogation of the GBM tumour microenvironment (TME) and identification of novel TME-specific subtypes could inform new precision immunotherapy treatment strategies. MATERIALS AND METHODS: A refined and validated microenvironment cell population (MCP) counter method was applied to >800 GBM patient tumours (GBM-MCP-counter). Specifically, partition around medoids (PAM) clustering of GBM-MCP-counter scores in the GLIOTRAIN discovery cohort identified three novel patient clusters, uniquely characterised by TME composition, functional orientation markers and immune checkpoint proteins. Validation was carried out in three independent GBM-RNA-seq datasets. Neoantigen, mutational and gene ontology analysis identified mutations and uniquely altered pathways across subtypes. The longitudinal Glioma Longitudinal AnalySiS (GLASS) cohort and three immunotherapy clinical trial cohorts [treatment with neoadjuvant/adjuvant anti-programmed cell death protein 1 (PD-1) or PSVRIPO] were further interrogated to assess subtype alterations between primary and recurrent tumours and to assess the utility of TME classifiers as immunotherapy biomarkers. RESULTS: TMEHigh tumours (30%) displayed elevated lymphocyte, myeloid cell immune checkpoint, programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 transcripts. TMEHigh/mesenchymal+ patients featured tertiary lymphoid structures. TMEMed (46%) tumours were enriched for endothelial cell gene expression profiles and displayed heterogeneous immune populations. TMELow (24%) tumours were manifest as an 'immune-desert' group. TME subtype transitions upon recurrence were identified in the longitudinal GLASS cohort. Assessment of GBM immunotherapy trial datasets revealed that TMEHigh patients receiving neoadjuvant anti-PD-1 had significantly increased overall survival (P = 0.04). Moreover, TMEHigh patients treated with adjuvant anti-PD-1 or oncolytic virus (PVSRIPO) showed a trend towards improved survival. CONCLUSIONS: We have established a novel TME-based classification system for application in intracranial malignancies. TME subtypes represent canonical 'termini a quo' (starting points) to support an improved precision immunotherapy treatment approach.

Characterizing individual trainee learning curves in surgical training: Challenges and opportunities.

The surgical learning curve is an observable and measurable phenomenon. In the era of competency-based approaches to surgical training, monitoring the trajectory of individual trainee competence attainment could represent a meaningful method of formative and summative assessment. While technology can assist this approach, a number of significant barriers to the implementation of such assessment methods remain, including: accurate data collection, standard setting, and reliable assessment. Translating individual learning curve data into quantifiable case minimum targets in training poses further difficulties, and may not be possible for all procedures, particularly those that are less frequently performed and assessed. In spite of these challenges, significant benefits could be realized through an individualized approach to competency assessment using trainee learning curve data. Tracking competence acquisition against criterion-referenced standards could allow for targeted training and remediation, conforming with modern theories of adult education and empowering trainees to take control of their own learning. Learning curve data could also be used to assess the effects of educational interventions such as simulation-based training on subsequent competence acquisition rates. Ultimately, the individual learning curves of trainees could be used to inform personalised decisions regarding entrustment, credentialing, and certification, allowing training programmes to move beyond minimum operative experience targets as a crude proxy measure of competence.

Risk factors associated with poorer experiences of end-of-life care and challenges in early bereavement: Results of a national online survey of people bereaved during the COVID-19 pandemic.

BACKGROUND: Experiences of end-of-life care and early bereavement during the COVID-19 pandemic are poorly understood. AIM: To identify clinical and demographic risk factors for sub-optimal end-of-life care and pandemic-related challenges prior to death and in early bereavement, to inform clinical practice, policy and bereavement support. DESIGN: Online national survey of adults bereaved in the UK (deaths between 16 March 2020 and 2 January 2021), recruited via media, social media, national associations and organisations. SETTING/PARTICIPANTS: 711 participants, mean age 49.5 (SD 12.9, range 18-90). 628 (88.6%) were female. Mean age of the deceased was 72.2 (SD 16.1, range miscarriage to 102 years). 311 (43.8%) deaths were from confirmed/suspected COVID-19. RESULTS: Deaths in hospital/care home increased the likelihood of poorer experiences at the end of life; for example, being unable to visit or say goodbye as wanted (p < 0.001). COVID-19 was also associated with worse experiences before and after death; for example, feeling unsupported by healthcare professionals (p < 0.001), social isolation/loneliness (OR = 0.439; 95% CI: 0.261-0.739), and limited contact with relatives/friends (OR = 0.465; 95% CI: 0.254-0.852). Expected deaths were associated with a higher likelihood of positive end-of-life care experiences. The deceased being a partner or child also increased the likelihood of positive experiences, however being a bereaved partner strongly increased odds of social isolation/loneliness, for example, OR = 0.092 (95% CI: 0.028-0.297) partner versus distant family member. CONCLUSIONS: Four clear risk factors were found for poorer end-of-life care and pandemic-related challenges in bereavement: place, cause and expectedness of death, and relationship to the deceased.

Understanding public attitudes to death talk and advance care planning in Northern Ireland using health behaviour change theory: a qualitative study.

OBJECTIVES: Advance care planning is a key preparatory step in ensuring high-quality palliative and end of life care, and should be considered as a process, beginning with community-level conversations among lay persons. There is, however, indication that death talk among community-dwelling adults is not occurring, and there is a dearth of research examining why this is the case. This study aims to provide the first examination of barriers and facilitators to talking about death and dying among the general population in a UK region (Northern Ireland), and to provide a novel application of health behaviour change theory towards developing a theoretical understanding of the sources of this behaviour. METHODS: The study involved qualitative analysis of responses (n = 381 participants) to two open-ended questions within a cross-sectional online survey, with recruitment via social media of adults currently living in Northern Ireland. Reflexive thematic analysis was conducted on open text responses per question, with the barriers and facilitators mapped on to health behaviour change models (the Behaviour Change Wheel COM-B and the Theoretical Domains Framework). RESULTS: The findings evidence a myriad of barriers and facilitators to engaging in death talk, with themes aligning to areas such as lack of acceptance of death in social contexts and fear of upsetting self or others, and a need to improve interpersonal communication skills for facilitating conversations and improve knowledge of the existing services around death and dying. A theoretical understanding of the drivers of death talk is presented with findings mapped across most components of the COM-B Behaviour Change Model and the Theoretical Domains Framework. CONCLUSIONS: This study contributes to a small but emergent research area examining barriers and facilitators to talking about death and dying. Findings from this study can be used to inform new public health programmes towards empowering adults to have these conversations with others in their community towards upstreaming advance care planning.

The role of altruism vs self-interest in COVID-19 vaccination uptake in the United Kingdom.

OBJECTIVES: The aim of the present study was to explore self-interest, kin altruism and non-kin altruism reasons that influence people to vaccinate against COVID-19. STUDY DESIGN: This was a cross-sectional study using a fully repeated measures design. METHODS: Participants (N = 178) answered questions on perceived threat and likelihood of infection, vaccination status and opinion on mandatory vaccination. Participants also rated a set of statements that asked how likely these would influence them and others to vaccinate against COVID-19. Statements reflected self-interest, kin altruism or non-kin altruism. RESULTS: Just more than half of the sample (50.8%) reported the likelihood of infection as somewhat or extremely likely, and almost three-fourths (74.2%) reported that COVID-19 posed a minor or moderate threat to their physical health. Almost three-fourths (74.3%) of the sample were vaccinated, with just more than half (56.2%) in favour of mandatory vaccination. A 2 (self/other) × 3 (self-interest/kin altruism/non-kin altruism) fully repeated measures analysis of variance showed that kin-altruistic reasons were rated most highly, regardless of whether this was regarding oneself or others. Participants rated others as having greater self-interest reasons for vaccination compared with oneself, whereas non-kin altruism reasons for vaccination were rated higher for oneself, compared with others. CONCLUSION: Highlighting the benefits of vaccination for close relatives and vulnerable others in the population would be a useful strategy for government to use when urging the public to vaccinate against COVID-19.

Mapping end-of-life and anticipatory medications in palliative care patients using a longitudinal general practice database.

OBJECTIVE: End-of-life and anticipatory medications (AMs) have been widely used in various health care settings for people approaching end-of-life. Lack of access to medications at times of need may result in unnecessary hospital admissions and increased patient and family distress in managing palliative care at home. The study aimed to map the use of end-of-life and AM in a cohort of palliative care patients through the use of the Population Level Analysis and Reporting Data Space and to discuss the results through stakeholder consultation of the relevant organizations. METHODS: A retrospective observational cohort study of 799 palliative care patients in 25 Australian general practice health records with a palliative care referral was undertaken over a period of 10 years. This was followed by stakeholders' consultation with palliative care nurse practitioners and general practitioners who have palliative care patients. RESULTS: End-of-life and AM prescribing have been increasing over the recent years. Only a small percentage (13.5%) of palliative care patients received medications through general practice. Stakeholders' consultation on AM prescribing showed that there is confusion about identifying patients needing medications for end-of-life and mixed knowledge about palliative care referral pathways. SIGNIFICANCE OF RESULTS: Improved knowledge and information around referral pathways enabling access to palliative care services for general practice patients and their caregivers are needed. Similarly, the increased utility of screening tools to identify patients with palliative care needs may be useful for health care practitioners to ensure timely care is provided.

IRF5 regulates airway macrophage metabolic responses.

Interferon regulatory factor 5 (IRF5) is a master regulator of macrophage phenotype and a key transcription factor involved in expression of proinflammatory cytokine responses to microbial and viral infection. Here, we show that IRF5 controls cellular and metabolic responses. By integrating ChIP sequencing (ChIP-Seq) and assay for transposase-accessible chromatin using sequencing (ATAC)-seq data sets, we found that IRF5 directly regulates metabolic genes such as hexokinase-2 (Hk2). The interaction of IRF5 and metabolic genes had a functional consequence, as Irf5-/- airway macrophages but not bone marrow-derived macrophages (BMDMs) were characterized by a quiescent metabolic phenotype at baseline and had reduced ability to utilize oxidative phosphorylation after Toll-like receptor (TLR)-3 activation, in comparison to controls, ex vivo. In a murine model of influenza infection, IRF5 deficiency had no effect on viral load in comparison to wild-type controls but controlled metabolic responses to viral infection, as IRF5 deficiency led to reduced expression of Sirt6 and Hk2. Together, our data indicate that IRF5 is a key component of AM metabolic responses following influenza infection and TLR-3 activation.

Exploring what is important to patients with regards to quality of life after experiencing a lower limb reconstructive procedure: a qualitative evidence synthesis.

BACKGROUND: Patient reported outcome measures (PROMs) are used to understand the impact of lower limb reconstruction surgery on patients' quality of life (QOL). Existing measures have not been developed to specifically capture patient experiences amongst adults with lower limb conditions that require reconstruction surgery. This review aimed to synthesise qualitative evidence to identify what is important to patients requiring, undergoing, or following reconstructive surgery for lower limb conditions. METHODS: MEDLINE, Embase, PsychINFO and Cinahl were searched from inception until November 2020. Studies were included if they employed qualitative research methods, involved patients requiring, undergoing or following lower limb reconstruction and explored patients' experiences of care, treatment, recovery and QOL. Mixed methods studies that did not separately report qualitative findings, mixed population studies that were not separately reported and studies in languages other than English were excluded. Included studies were analysed using thematic synthesis. The Critical Appraisal Skills Programme qualitative studies checklist was used to undertake quality assessment. RESULTS: Nine studies met the inclusion criteria. The thematic synthesis identified two overarching themes: (1) areas of living key to QOL for lower limb reconstruction patients and (2) moving towards a new normal. The way in which lower limb reconstruction affects an individual's QOL and their recovery is complex and is influenced by a range of inter-related factors, which will affect patients to varying degrees depending on their individual circumstances. We identified these factors as: pain, daily functioning and lifestyle, identity, income, emotional wellbeing, support, the ability to adapt and adjust and the ability to move forwards. CONCLUSIONS: The way patients' QOL is affected after a lower limb reconstruction is complex, may change over time and is strongly linked to their recovery. These findings will aid us in developing a conceptual framework which identifies the outcomes important to patients and those that should be included in a PROM. Further research is then required to establish whether the range of factors we identified are captured by existing PROMs. Depending on the outcome of this work, a new PROM for patients following lower limb reconstruction may be required.

Cancer and breast cancer awareness interventions in an intellectual disability context: A review of the literature.

BACKGROUND: Women with an intellectual disability (ID) have a similar risk of developing breast cancer as women in the general population yet present with later stage breast cancers, which have poorer outcomes. AIM: To identify whether there is a need to develop a breast cancer awareness intervention for women with an ID. METHODS: Interventions aimed at increasing cancer awareness and breast cancer awareness for people with an ID were identified and critically appraised. RESULTS: Five interventions to increase cancer awareness or breast cancer awareness in people with an ID were identified. CONCLUSION: The review highlighted the paucity of theoretically underpinned breast cancer awareness interventions specifically aimed at women with an ID. Facilitating breast cancer awareness for women with an ID could potentially lead to earlier presentation of potential symptoms of breast cancer, earlier treatment, better prognosis and ultimately, improved survival. This article establishes that there is a need for an intervention underpinned by theory to increase breast cancer awareness in women with an ID.

New hints towards a precision medicine strategy for IDH wild-type glioblastoma.

Glioblastoma represents the most common primary malignancy of the central nervous system in adults and remains a largely incurable disease. The elucidation of disease subtypes based on mutational profiling, gene expression and DNA methylation has so far failed to translate into improved clinical outcomes. However, new knowledge emerging from the subtyping effort in the IDH-wild-type setting may provide directions for future precision therapies. Here, we review recent learnings in the field, and further consider how tumour microenvironment differences across subtypes may reveal novel contexts of vulnerability. We discuss recent treatment approaches and ongoing trials in the IDH-wild-type glioblastoma setting, and propose an integrated discovery stratagem incorporating multi-omics, single-cell technologies and computational approaches.

Ingestion of foreign materials by odontocetes along the Catalan coast: causes and consequences.

Ingestion of abnormal materials by cetaceans has been reported worldwide, but few studies have investigated the causes of foreign material ingestion. We retrospectively analysed necropsies performed between 2012 and 2019 on 88 cetaceans stranded along the coast of Catalonia, Spain, and evaluated the association of abnormal ingested materials with 2 risk factors, namely disease of the central nervous system (CNS) and maternal separation. Abnormal materials were found in the digestive tract in 19 of 88 (21.6%) cetaceans; of these, 13 (60%) had lesions in the CNS, such as morbilliviral encephalitis, neurobrucellosis or encephalomalacia, and 3 were diagnosed as having experienced maternal separation. In a logistic regression model, CNS lesions and maternal separation were identified as risk factors for ingestion of foreign material, but with wide confidence intervals, probably due to the small sample size. In contrast, abnormal ingestion was not identified in any of the 25 (28%) cetaceans whose cause of death was attributed to interaction with humans. Abnormal ingestion should be interpreted with caution, and efforts should be made at necropsy to exclude CNS diseases through pathologic and microbiologic investigations. If disease of the CNS is a significant risk factor for ingestion of marine debris by small odontocetes, results of monitoring programmes may be biased by the prevalence of CNS disease in a specific area or population.

Fluopyram Suppresses Population Densities of Heterodera glycines in Field and Greenhouse Studies in Michigan.

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, causes significant damage to soybean production annually. Fluopyram is a fungicide commonly used in soybean seed treatments intended to control soilborne fungal pathogens; however, recent studies have also suggested inhibitory effects on SCN. We examined the effects of a fluopyram seed treatment, ILeVO, on SCN reproduction, sudden death syndrome (SDS) development, and yield in a 3-year field study. Overall, fluopyram had a significant effect on yield (P = 0.046) and end-of-season SCN eggs and second-stage juveniles (Pf, P = 0.033) but no significant effect on SCN reproduction (Rf) or SDS disease index (P > 0.05). Post hoc tests indicated that fluopyram increased yield and suppressed SCN quantities. However, Rf was consistently greater than 1 whether or not the seed was treated with fluopyram, indicating that SCN populations were still increasing in the presence of fluopyram. A follow-up greenhouse study indicated that fluopyram reduced SCN relative to nontreated controls, as observed in the field, but only reduced SCN DNA within roots of a susceptible cultivar. These results indicate that fluopyram can suppress SCN quantities relative to nontreated seed but may not successfully reduce nematode populations without the use of additional management strategies.

Variation in Mycobacterium bovis genetic richness suggests that inwards cattle movements are a more important source of infection in beef herds than in dairy herds.

BACKGROUND: We used genetic Multi-Locus VNTR Analysis (MLVA) data gathered from surveillance efforts to better understand the ongoing bovine tuberculosis (bTB) epidemic in Northern Irish cattle herds. We modelled the factors associated with Mycobacterium bovis MLVA genotype richness at three analytical scales; breakdown level, herd level, and patch level, and compared the results between dairy and non-dairy production types. RESULTS: In 83% of breakdowns and in 63% of herds, a single MLVA genotype was isolated. Five or more MLVA genotypes were found in less than 3 % of herds. Herd size and the total number of reactors were important explanatory variables, suggesting that increasing MLVA genotype richness was positively related to increases in the number of host animals. Despite their smaller relative size, however, the highest MLVA genotype richness values were observed in non-dairy herds. Increasing inwards cattle movements were important positive predictors of MLVA genotype richness, but mainly in non-dairy settings. CONCLUSIONS: The principal finding is that low MLVA genotype richness indicates that small-scale epidemics, e.g. wildlife, contiguous farms, and within-herd recrudescence, are important routes of M. bovis infection in cattle herds. We hypothesise that these mechanisms will maintain, but may not explicitly increase, MLVA genotype richness. The presence of elevated MLVA richness is relatively rare and likely indicates beef fattening enterprises, which purchase cattle from over long distances. Cattle movements were furthermore an important predictor of MLVA genotype richness in non-dairy herds, but not in dairy herds; this may represent reduced cattle purchasing levels in dairy enterprises, compared to beef. These observations allude to the relative contribution of different routes of bTB infection between production types; we posit that infection associated with local factors may be more evident in dairy herds than beef herds, however in beef herds, inwards movements offer additional opportunities for introducing M. bovis into the herd.

Integrated Effects of Genetic Resistance and Prothioconazole + Tebuconazole Application Timing on Fusarium Head Blight in Wheat.

Integrated Fusarium head blight (FHB) management programs consisting of different combinations of cultivar resistance class and an application of the fungicide prothioconazole + tebuconazole at or after 50% early anthesis were evaluated for efficacy against FHB incidence (INC; percentage of diseased spikes), index (IND; percentage of diseased spikelets per spike), Fusarium damaged kernel (FDK), deoxynivalenol (DON) toxin contamination, grain yield, and test weight (TW) in inoculated field trials conducted in 11 U.S. states in 2014 and 2015. Mean log response ratios and corresponding percent control values for INC, IND, FDK, and DON, and mean differences in yield and TW relative to a nontreated, inoculated susceptible check (S_CK), were estimated through network meta-analyses as measures of efficacy. Results from the analyses were then used to estimate the economic benefit of each management program for a range of grain prices and fungicide applications costs. Management programs consisting of a moderately resistant (MR) cultivar treated with the fungicide were the most efficacious, reducing INC by 60 to 69%, IND by 71 to 76%, FDK by 66 to 72%, and DON by 60 to 64% relative to S_CK, compared with 56 to 62% for INC, 68 to 72% for IND, 66 to 68% for FDK, and 58 to 61% for DON for programs with a moderately susceptible (MS) cultivar. The least efficacious programs were those with a fungicide application to a susceptible (S) cultivar, with less than a 45% reduction of INC, IND, FDK, or DON. All programs were more efficacious under conditions favorable for FHB compared with less favorable conditions, with applications made at 50% early anthesis being of comparable efficacy to those made 2 to 7 days later. Programs with an MS cultivar resulted in the highest mean yield increases relative to S_CK (541 to 753 kg/ha), followed by programs with an S cultivar (386 to 498 kg/ha) and programs with an MR cultivar (250 to 337 kg/ha). Integrated management programs with an MS or MR cultivar treated with the fungicide at or after 50% early anthesis were the most likely to result in a 50 or 75% control of IND, FDK, or DON in a future trial. At a fixed fungicide application cost, these programs were $4 to $319/MT more economically beneficial than corresponding fungicide-only programs, depending on the cultivar and grain price. These findings demonstrate the benefits of combining genetic resistance with a prothioconazole + tebuconazole treatment to manage FHB, even if that treatment is applied a few days after 50% early anthesis.

Application of multi-criteria decision analysis to assess sampling strategies in eutrophic urbanized waterbodies.

Different water quality sampling practices such as location selection or frequency can inform future watershed management strategies. The objective of this work was to compare water quality sampling strategies based on different weighted criteria to determine the optimal sampling frequency and sampling location for an urbanized, eutrophic, freshwater system. Weekly water sampling was conducted over a 2-year period at five locations for six water quality parameters. This high frequency (HF) dataset was then deconstructed into a lower frequency (LF) dataset to simulate a monthly sampling strategy. Statistical analyses conducted showed that for all sampling locations the LF datasets were not significantly different from the HF datasets, suggesting monthly sampling is sufficient to capture the overall water quality conditions in this system. A multi-criteria decision analysis was constructed for statistical and operational criteria to determine the optimal sampling locations given different criteria weights. Results showed that the optimal sampling location changed depending on the criteria weighting, suggesting that statistical analyses alone would not be sufficient to determine optimal sampling locations in this system. This analysis was then used if optimal sampling location depended on specific water quality monitoring goals. Results showed that the optimal location depends on the particular water quality monitoring goals and that this effect should also be considered in the design of future sampling programs.

Horizontal and vertical distribution of sea lice larvae (Lepeophtheirus salmonis) in and around salmon farms in the Bay of Fundy, Canada.

The sea louse, Lepeophtheirus salmonis, is parasitic to salmonid species in the Northern Hemisphere and has become a widespread biological and economic problem for the salmon farming industry. A better understanding is needed of their spatial distribution and early life history to disrupt the life cycle of the sea louse. In this study, sea lice larval densities within salmon farms, between salmon farms and reference sites, and at various depths were quantified using both plankton pumps and plankton nets. Farm sites exhibited significantly higher densities than reference sites; however, these densities dropped an order of magnitude at a distance of 100 m from the cages. The majority of the larvae captured in the study were nauplii (93%), and densities ranged from 0 to 10 larvae/m3 . Free-swimming sea lice larvae were found to exhibit a diel cycle where nauplii larvae were in deeper waters (10-17 m) during the day and in surface waters (1-6 m) during the night. The results of this study suggest that the early life-history stages of sea lice originate from and may remain close to active salmon farms, creating a self-sustaining population.