No abstract

Bat communities can usually only be comprehensively monitored by combining ultrasound recording and trapping techniques. Here, we propose bat point counts, a novel, single method to sample all flying bats. We designed a sampling rig that combines a thermal scope to detect flying bats and their flight patterns, an ultrasound recorder to identify echolocating bat calls, and a near-infrared camera and LED illuminator to photograph bat morphology. We evaluated the usefulness of the flight pattern information, echolocation call recordings, and near-infrared photographs produced by our sampling rig to determine a workflow to process these heterogenous data types. We present a conservative workflow to enable taxonomic discrimination and identification of bat detections. Our sampling rig and workflow allowed us to detect both echolocating and non-echolocating bats and we could assign 84% of the detections to a guild. Subsequent identification can be carried out with established methods such as identification keys and call libraries, based on the visible morphological features and echolocation calls. Currently, a higher near-infrared picture quality is required to resolve more detailed diagnostic morphology, but there is considerable potential to extract more information with higher-intensity illumination. This is the first proof-of-concept for bat point counts, a method that can passively sample all flying bats in their natural environment.

Very limited information is available on the relationship between dietary selenium (Se) and plant protein (PP) sources in carnivorous marine aquaculture species. Therefore, this study employed a 2  3 experimental layout to investigate the effects of lupin meal (LM) protein inclusion levels (0, 25 and 75%) and organic selenium (OS) levels (0 or 2 g kg-1) on the growth, physiology and histopathology of juvenile barramundi (Lates calcarifer). The experimental diets (LM 0 , LM 0+OS , LM 25 , LM 25+OS , LM 75 and LM 75+OS) were formulated on an isonitrogenous (48.8% crude protein) and isocalorific (20.6 MJ kg-1 gross energy) basis. In the 60-day feeding experiment, final weight (FW), specific growth rate (SGR) and weight gain (WG) were improved by the supplementation of Se in LM-based diets. Fish fed diets containing Se had higher FW, SGR and WG compared with those fed diets lacking Se supplementation (P  0.05). Both LM inclusion levels and Se supplementation levels affected the apparent digestibility coefficient of protein (ADC-P). Meanwhile, survival and the thermal growth coefficient (TGC) were not significantly different among all dietary treatments. The inclusion of a high LM level resulted in decreased glutathione peroxidase (GPx) activities, but this effect was not observed when Se was supplemented in the diets. Furthermore, there was a linear relationship between muscle Se level and Se concentration of the experimental diets. Se-induced myopathy was observed in skeletal muscles of fish fed LM diets without Se supplementation. In addition, structural alteration was found in the liver; however, the kidney, spleen and intestine were histologically normal. Overall, these results suggest that high LM diets supplemented with organic selenium can enhance growth, physiological and histological performances of juvenile barramundi.

No abstract

Bat communities can usually only be comprehensively monitored by combining ultrasound recording and trapping techniques. Here, we propose bat point counts, a novel, single method to sample all flying bats. We designed a sampling rig that combines a thermal scope to detect flying bats and their flight patterns, an ultrasound recorder to identify echolocating bat calls, and a near-infrared camera and LED illuminator to photograph bat morphology. We evaluated the usefulness of the flight pattern information, echolocation call recordings, and near-infrared photographs produced by our sampling rig to determine a workflow to process these heterogenous data types. We present a conservative workflow to enable taxonomic discrimination and identification of bat detections. Our sampling rig and workflow allowed us to detect both echolocating and non-echolocating bats and we could assign 84% of the detections to a guild. Subsequent identification can be carried out with established methods such as taxonomic keys and call libraries, based on the visible morphological features and echolocation calls. Currently, a higher near-infrared picture quality is required to resolve more detailed diagnostic morphology, but there is considerable potential to extract more information with higher-intensity illumination. This is the first proof-of-concept for bat point counts, a method that can passively sample all flying bats in their natural environment.