Bottom trawl fishing footprints on the world's continental shelves.

Bottom trawlers land around 19 million tons of fish and invertebrates annually, almost one-quarter of wild marine landings. The extent of bottom trawling footprint (seabed area trawled at least once in a specified region and time period) is often contested but poorly described. We quantify footprints using high-resolution satellite vessel monitoring system (VMS) and logbook data on 24 continental shelves and slopes to 1,000-m depth over at least 2 years. Trawling footprint varied markedly among regions: from <10% of seabed area in Australian and New Zealand waters, the Aleutian Islands, East Bering Sea, South Chile, and Gulf of Alaska to >50% in some European seas. Overall, 14% of the 7.8 million-km2 study area was trawled, and 86% was not trawled. Trawling activity was aggregated; the most intensively trawled areas accounting for 90% of activity comprised 77% of footprint on average. Regional swept area ratio (SAR; ratio of total swept area trawled annually to total area of region, a metric of trawling intensity) and footprint area were related, providing an approach to estimate regional trawling footprints when high-resolution spatial data are unavailable. If SAR was ≤0.1, as in 8 of 24 regions, there was >95% probability that >90% of seabed was not trawled. If SAR was 7.9, equal to the highest SAR recorded, there was >95% probability that >70% of seabed was trawled. Footprints were smaller and SAR was ≤0.25 in regions where fishing rates consistently met international sustainability benchmarks for fish stocks, implying collateral environmental benefits from sustainable fishing.

Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance.

Bottom trawling is the most widespread human activity affecting seabed habitats. Here, we collate all available data for experimental and comparative studies of trawling impacts on whole communities of seabed macroinvertebrates on sedimentary habitats and develop widely applicable methods to estimate depletion and recovery rates of biota after trawling. Depletion of biota and trawl penetration into the seabed are highly correlated. Otter trawls caused the least depletion, removing 6% of biota per pass and penetrating the seabed on average down to 2.4 cm, whereas hydraulic dredges caused the most depletion, removing 41% of biota and penetrating the seabed on average 16.1 cm. Median recovery times posttrawling (from 50 to 95% of unimpacted biomass) ranged between 1.9 and 6.4 y. By accounting for the effects of penetration depth, environmental variation, and uncertainty, the models explained much of the variability of depletion and recovery estimates from single studies. Coupled with large-scale, high-resolution maps of trawling frequency and habitat, our estimates of depletion and recovery rates enable the assessment of trawling impacts on unprecedented spatial scales.

The SIESTA Trial: A Randomized Study Investigating the Efficacy, Safety, and Tolerability of Acupressure versus Sham Therapy for Improving Sleep Quality in Patients with End-Stage Kidney Disease on Hemodialysis.

Objectives. To compare the effectiveness of real acupressure versus sham acupressure therapy in improving sleep quality in patients receiving hemodialysis (HD) or hemodiafiltration (HDF). Methods. A multicenter, single-blind, randomized controlled trial was conducted in two Australian dialysis units located in Princess Alexandra Hospital and Logan Hospital, respectively. Forty-two subjects with self-reported poor sleep quality were randomly assigned to real (n = 21) or sham (n = 21) acupressure therapy delivered thrice weekly for four consecutive weeks during routine dialysis sessions. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) score measured at week four adjusted for baseline PSQI measurements. Secondary outcomes were quality of life (QOL) (SF-8), adverse events, and patient acceptability (treatment acceptability questionnaire, TAQ). Results. The two groups were comparable on global PSQI scores (difference 0.19, 95% confidence interval [CI] -1.32 to 1.70) and on the subscale scores. Similar results were observed for QOL both in the mental (difference -3.88, 95% CI -8.63 to 0.87) and the physical scores (difference 2.45, 95% CI -1.69 to 6.58). There were no treatment-related adverse events and acupressure was perceived favorably by participants. Conclusion. Acupressure is a safe, well-tolerated, and highly acceptable therapy in adult hemodialysis patients in a Western healthcare setting with uncertain implications for therapeutic efficacy.