Global COVID-19 lockdown highlights humans as both threats and custodians of the environment

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus, initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness.

Using tri-axial accelerometer loggers to identify spawning behaviours of large pelagic fish

BACKGROUND

Tri-axial accelerometers have been used to remotely describe and identify in situ behaviours of a range of animals without requiring direct observations. Datasets collected from these accelerometers (i.e. acceleration, body position) are often large, requiring development of semi-automated analyses to classify behaviours. Marine fishes exhibit many "burst" behaviours with high amplitude accelerations that are difficult to interpret and differentiate. This has constrained the development of accurate automated techniques to identify different "burst" behaviours occurring naturally, where direct observations are not possible.

METHODS

We trained a random forest machine learning algorithm based on 624 h of accelerometer data from six captive yellowtail kingfish during spawning periods. We identified five distinct behaviours (swim, feed, chafe, escape, and courtship), which were used to train the model based on 58 predictive variables.

RESULTS

Overall accuracy of the model was 94%. Classification of each behavioural class was variable; F₁ scores ranged from 0.48 (chafe) - 0.99 (swim). The model was subsequently applied to accelerometer data from eight free-ranging kingfish, and all behaviour classes described from captive fish were predicted by the model to occur, including 19 events of courtship behaviours ranging from 3 s to 108 min in duration.

CONCLUSION

Our findings provide a novel approach of applying a supervised machine learning model on free-ranging animals, which has previously been predominantly constrained to direct observations of behaviours and not predicted from an unseen dataset. Additionally, our findings identify typically ambiguous spawning and courtship behaviours of a large pelagic fish as they naturally occur.

The power of national acoustic tracking networks to assess the impacts of human activity on marine organisms during the COVID-19 pandemic

COVID-19 restrictions have led to an unprecedented global hiatus in anthropogenic activities, providing a unique opportunity to assess human impact on biological systems. Here, we describe how a national network of acoustic tracking receivers can be leveraged to assess the effects of human activity on animal movement and space use during such global disruptions. We outline variation in restrictions on human activity across Australian states and describe four mechanisms affecting human interactions with the marine environment: 1) reduction in economy and trade changing shipping traffic; 2) changes in export markets affecting commercial fisheries; 3) alterations in recreational activities; and 4) decline in tourism. We develop a roadmap for the analysis of acoustic tracking data across various scales using Australia's national Integrated Marine Observing System (IMOS) Animal Tracking Facility as a case study. We illustrate the benefit of sustained observing systems and monitoring programs by assessing how a 51-day break in white shark (Carcharodon carcharias) cage-diving tourism due to COVID-19 restrictions affected the behaviour and space use of two resident species. This cessation of tourism activities represents the longest break since cage-diving vessels started day trips in this area in 2007. Long-term monitoring of the local environment reveals that the activity space of yellowtail kingfish (Seriola lalandi) was reduced when cage-diving boats were absent compared to periods following standard tourism operations. However, white shark residency and movements were not affected. Our roadmap is globally applicable and will assist researchers in designing studies to assess how anthropogenic activities can impact animal movement and distributions during regional, short-term through to major, unexpected disruptions like the COVID-19 pandemic.

Diet composition and diel feeding behaviour of the banded guitarfish Zapteryx xyster along the Pacific coast of Costa Rica, Central America

The diet and diel feeding behaviour of the banded guitarfish Zapteryx xyster were examined along the Pacific coast of Costa Rica. A sample of 235 stomachs was collected between March 2010 and December 2011 as part of an ongoing shrimp-trawl by-catch monitoring programme. Samples from multiple day and night periods allowed testing the hypothesis that Z. xyster is more active at night, thus increasing the amount of food intake during night-time. Overall, shrimps (52·3% prey-specific index of relative importance, P(SIRIi) ) and teleosts (27·2% P(SIRIi) ) were the most important prey categories. Juveniles fed primarily on smaller shrimps (Solenocera spp.), while adults shifted to larger prey. The amount of food consumed (as % of bodymass) by juvenile and adult Z. xyster increased significantly between 0400 and 1200 hours, while the proportion of empty stomachs decreased during the same time interval. These findings contradict the hypothesis that Z. xyster is more active and feeds at night. The study also revealed that Z. xyster, particularly juveniles, forage on several shrimp species and overlap spatially with the Costa Rican bottom-trawl fisheries. This has important management and conservation implications as Z. xyster may be experiencing high by-catch rates, and because of their life history is presumed to be vulnerable to intense levels of exploitation.

Ontogenetic dietary shifts and feeding ecology of the rasptail skate Raja velezi and the brown smoothhound shark Mustelus henlei along the Pacific coast of Costa Rica, Central America

Stomachs from 511 Raja velezi and 340 Mustelus henlei captured as by-catch in the commercial trawling fishery (2010-2012) were analysed to examine diet composition, ontogenetic shifts and degree of dietary overlap between species life stages in the Pacific Ocean of Costa Rica. Shrimps were the most important prey categories in the diet of R. velezi, while teleosts and cephalopods dominated the diet of M. henlei. Diet comparisons between different stages of R. velezi and M. henlei revealed clear ontogenetic dietary shifts: crustaceans (mainly shrimps, crabs and stomatopods) dominated the diet of immature individuals, and adults had a higher proportion of teleosts. The results suggest that R. velezi is an epibenthic predator that specializes in shrimps during early life stages, and to a lesser extent, teleosts as it matures, while M. henlei is an opportunistic predator with a highly diverse diet consisting of teleosts, cephalopods, shrimps and stomatopods. This study also found little evidence of dietary overlap between species or life stages and suggests that intra- and interspecific competition between R. velezi and M. henlei may be reduced by: (1) diet specialization in immature stages of R. velezi, (2) ontogenetic dietary shifts between immature and mature individuals, (3) prey-size selectivity in larger individuals of R. velezi and (4) differences in depth utilization in overlapping geographical regions.

Production and evaluation of syngeneic antibodies showing specificity for the A15 A5 transplantable rat glioma

Antibodies have been raised which show specificity for the A15 A5 transplantable rat glioma model. Viable, irradiated, colcemid-treated and microwave-fixed A15 A5 cells were each used to hyperimmunize BDIX rats by subcutaneous inoculation, while viable cells were also injected intracerebrally into syngeneic animals. Specific anti-A15 A5 antibodies were detected in serum by a modified enzyme-linked immunoabsorbent assay (ELISA). Immunoperoxidase and immunofluorescence cytochemistry revealed the presence of antigen in paraffin-wax and frozen sections, respectively, of A15 A5 gliomas. The different methods of immunogen denaturation were found to affect the degree of immunological potency of the cells. This study has shown that A15 A5 cells are immunogenic in a syngeneic host. Intracerebrally transplanted, viable cells produced antibodies of higher titre than subcutaneously-injected, denatured cells. The anti-A15 A5 antisera may be used for detection of neoplastic rat astrocytes using immunocytochemistry. These antibodies will prove to be of value in discriminating between neoplastic and normal cells at the tumor/brain interface.

Intensive cognitive-behaviour group therapy for diagnostically heterogeneous groups of patients with psychiatric disorder

This uncontrolled study evaluates the efficacy of a combined treatment of medications (for the majority of patients) and a closed group, intensive (two-week) cognitive-behaviour therapy programme for heterogeneous groups of psychiatric patients. Five hundred and thirty-one patients at a private psychiatric clinic were included in the study. Self-report measures of depression, anxiety, self-esteem and "locus of control" were administered before and after treatment and at intervals up to one year later. Statistically and clinically significant improvements were found in all measures and these improvements were maintained up to one year. The results provide support for the efficacy of the treatment.

Plasma concentrations of dothiepin and its metabolites are not correlated with clinical efficacy in major depressive illness

Plasma concentration-antidepressant response relationships for dothiepin, nordothiepin, dothiepin-S-oxide, and nordothiepin-S-oxide were investigated in 50 patients (33 women and 17 men), who had had a major depressive episode. Depression and anxiety were assessed at the start of therapy and after 2 and 4 weeks by measurement of a Hamilton rating score for depression (HRSD), a Beck depression inventory (BECK), visual analog scores for depression (VASDEP) and anxiety (VASANX), and a physician's global (GLOBAL) score. There were significant (p < 0.001) decreases in both mean depression (32-69%) and mean anxiety (30-44%) scores at weeks 2 and 4, but there were no robust linear or polynomial correlations between percent decrease in depression or anxiety scores and plasma concentrations of dothiepin or its metabolites at week 4. It is suggested that measurement of the nordothiepin/dothiepin ratio may assist in the assessment of compliance.

Growth factor modulation of surface ganglioside expression in cloned neoplastic glia

Cloned neoplastic astrocytes from a human glioma-derived cell line (IPSB-18) were grown in fetal calf serum (FCS)-supplemented culture medium in the presence of three growth factors. Basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) but not platelet-derived growth factor (PDGF) induced an increase in the number of cells positive for the ganglioside-recognizing monoclonal antibody, A2B5. No such growth factor-mediated induction could be detected in cells maintained in plasma-derived serum (PDS)-supplemented medium. Small molecules, removed from PDS during dialysis, may, therefore, act synergistically with growth factors in the control of ganglioside synthesis.

A human glioma cell line retaining expression of GFAP and gangliosides, recognized by A2B5 and LB1 antibodies, after prolonged passage

A malignant astrocytoma was cultured from a tissue biopsy taken at surgical resection, and serially passaged 65 times over a period of 4 years. Early culture cells showed a variety of morphological types, but were all positively labelled with a polyclonal antibody directed against glial fibrillary acidic protein (GFAP). As the number of passages increased small, GFAP-positive cells became the predominant cell type. Flow cytometry demonstrated changes in GFAP expression between early and late passages; early passages showing greater fluorescence intensity than those at later passages. All cells, however, remained positive for GFAP. In addition, this line (IPSB-18) was both vimentin and glutamine synthetase positive and no change in the expression of these two proteins was detectable on continued sequential passaging. Fibronectin was not detectable at any stage. As the number of passages increased, the population doubling time was shortened from 72 h at passage 5, to 28 h at passage 30. This line is unusual in its retention of GFAP expression through 65 sequential passages; the majority of astrocytoma lines lose this capacity after a few passages in vitro. The monoclonal antibody, A2B5, which recognizes surface gangliosides, has been previously shown to identify sub-set type 2 astrocytes in normal neural tissue in vitro. The expression of A2B5 gangliosides by 5-20% of GFAP-positive IPSB-18 cells, and their co-expression with the ganglioside GD3 identified by the LB1 monoclonal antibody, shows that cells with a similar phenotype to the type 1 and type 2 astrocytes of optic nerve are present in cultured gliomas, even after long term sequential passaging.