Flatfish herding behavior in response to trawl sweeps: a comparison of diel responses to conventional sweeps and elevated sweeps

Commercial bottom trawls often have sweeps to herd fish into the net. Elevation of the sweeps off the seaf loor may reduce seafloor disturbance, but also reduce herding effectiveness. In both field and laboratory experiments, we examined the behavior of flatfish in response to sweeps. We tested the hypotheses that 1) sweeps are more effective at herding flatfish during the day than at night, when fish are unable to see approaching gear, and that 2) elevation of sweeps off the seafloor reduces herding during the day, but not at night. In sea trials, day catches were greater than night catches for four out of six flatfish species examined. The elevation of sweeps 10 cm significantly decreased catches during the day, but not at night. Laboratory experiments revealed northern rock sole (Lepidopsetta polyxystra) and Pacific halibut (Hippoglossus stenolepis) were more likely to be herded\ud by the sweep in the light, whereas in the dark they tended to pass under or over the sweep. In the light, elevation of the sweep reduced herding, and more fish passed under the sweep. In contrast, in the dark, sweep elevation had little effect upon the number of fish that exhibited herding behavior. The results of both field and laboratory experiments were consistent with the premise that vision is the principle sensory input that controls fish behavior and orientation to trawl gear, and gear performance will differ between conditions where flatfish can see, in contrast to where they cannot see, the approaching gear

Temperature-dependent growth and behavior of juvenile Arctic cod (Boreogadus saida) and co-occurring North Pacific gadids

The thermal sensitivity of Arctic fish species is poorly understood, yet such data are a critical component of forecasting and understanding ecosystem impacts of climate change. In this study, we experimentally measured temperature-dependent growth and routine swim activity in the juvenile stage of two Arctic gadids (Arctic cod, Boreogadus saida and saffron cod, Eleginus gracilis) and two North Pacific gadids (walleye pollock, Gadus chalcogrammus and Pacific cod, Gadus macrocephalus) over a 6-week growth period across five temperatures (0, 5, 9, 16 and 20°C). Arctic cod demonstrated a cold-water, stenothermic response in that there was relatively high growth at 0°C (0.73 % day⁻¹), near-maximal growth at 5°C (1.35 % day⁻¹) and negative impacts on activity, growth and survival at 16 °C. In contrast, saffron cod demonstrated a warmer-water, eurythermic response, and temperature had a positive effect on growth and condition beyond 16°C. However, despite these distinct thermal responses, walleye pollock and Pacific cod grew 2–3 times faster than Arctic gadids across a relatively broad temperature range above 5°C. These results, coupled with possible northward expansion by both Pacific cod and walleye pollock, suggest Arctic cod are highly vulnerable to continued climate change in the Arctic, especially in coastal areas of the Beaufort and Chukchi Seas where temperatures already exceed 14°C in the summer growth period.This is the publisher’s final pdf. The article is copyrighted by the US Government and published by Springer. It can be found at: http://link.springer.com/journal/300Keywords: Climate change, Saffron cod, Walleye pollock, Thermal sensitivity, Pacific cod, Biogeograph

Epigenetic clocks indicate that kidney transplantation and not dialysis mitigate the effects of renal ageing

Background: Chronic kidney disease (CKD) is an age-related disease that displays multiple features of accelerated ageing. It is currently unclear whether the two treatment options for end-stage kidney disease (dialysis and kidney transplantation [KT]) ameliorate the accelerated uremic ageing process. Methods: Data on clinical variables and blood DNA methylation (DNAm) from CKD stage G3–G5 patients were used to estimate biological age based on blood biomarkers (phenotypic age [PA], n = 333), skin autofluorescence (SAF age, n = 199) and DNAm (Horvath, Hannum and PhenoAge clocks, n = 47). In the DNAm cohort, we also measured the change in biological age 1 year after the KT or initiation of dialysis. Healthy subjects recruited from the general population were included as controls. Results: All three DNAm clocks indicated an increased biological age in CKD G5. However, PA and SAF age tended to produce implausibly large estimates of biological age in CKD G5. By contrast, DNAm age was 4.9 years (p = 0.005) higher in the transplantation group and 5.9 years (p = 0.001) higher in the dialysis group compared to controls. This age acceleration was significantly reduced 1 year after KT, but not after 1 year of dialysis. Conclusions: Kidney failure patients displayed an increased biological age as estimated by DNAm clocks compared to population-based controls. Our results suggest that KT, but not dialysis, partially reduces the age acceleration

Foxf2: A Novel Locus for Anterior Segment Dysgenesis Adjacent to the Foxc1 Gene

Anterior segment dysgenesis (ASD) is characterised by an abnormal migration of neural crest cells or an aberrant differentiation of the mesenchymal cells during the formation of the eye's anterior segment. These abnormalities result in multiple tissue defects affecting the iris, cornea and drainage structures of the iridocorneal angle including the ciliary body, trabecular meshwork and Schlemm's canal. In some cases, abnormal ASD development leads to glaucoma, which is usually associated with increased intraocular pressure. Haploinsufficiency through mutation or chromosomal deletion of the human FOXC1 transcription factor gene or duplications of the 6p25 region is associated with a spectrum of ocular abnormalities including ASD. However, mapping data and phenotype analysis of human deletions suggests that an additional locus for this condition may be present in the same chromosomal region as FOXC1. DHPLC screening of ENU mutagenised mouse archival tissue revealed five novel mouse Foxf2 mutations. Re-derivation of one of these (the Foxf2W174R mouse lineage) resulted in heterozygote mice that exhibited thinning of the iris stroma, hyperplasia of the trabecular meshwork, small or absent Schlemm's canal and a reduction in the iridocorneal angle. Homozygous E18.5 mice showed absence of ciliary body projections, demonstrating a critical role for Foxf2 in the developing eye. These data provide evidence that the Foxf2 gene, separated from Foxc1 by less than 70 kb of genomic sequence (250 kb in human DNA), may explain human abnormalities in some cases of ASD where FOXC1 has been excluded genetically

The use of monthly indicators to forecast quarterly GDP in the short run: an application to the G7 countries

The delayed release of the National Account data for GDP is an impediment to the early understanding of the economic situation. In the short run, this information gap may be at least partially eliminated by bridge models (BM) which exploit the information content of timely updated monthly indicators. In this paper we examine the forecasting ability of BM for GDP growth in the G7 countries and compare their performance to that of univariate and multivariate statistical benchmark models. We run four alternative one-quarter ahead forecasting experiments to assess BM performance in situations as close as possible to the actual forecasting activity. BM are estimated for GDP both for single countries (US, Japan, Germany, France, UK, Italy, and Canada), and area-wide (G7, European Union, and Euro area). BM forecasting ability is always superior to that of benchmark models, provided that at least some monthly indicator data are available over the forecasting horizon