Electric fish handling gloves (FHGs) have been developed to immobilize fish during handling, with the potential benefit of reducing the time needed for sedation and recovery of fish relative to chemical anaesthetics. We examined the secondary stress responses (i.e., hematocrit, blood glucose, lactate, and pH) and reflex responses of Largemouth Bass Micropterus salmoides that were immobilized in water using electric FHGs for multiple durations (0, 30, and 120 s) relative to fish that were handled using only bare hands in water. We also evaluated the efficacy of the immobilization by quantifying the number of volitional movements that were observed during handling. Our findings suggested that when FHGs were used, fish tended to remain still (i.e., to show full reflex impairment) during handling relative to controls. Fish that were held with FHGs showed negligible reflex impairment immediately after the electricity was terminated. After a 30‐min posttreatment retention period, blood chemistry and ventilation rates were similar between fish held with FHGs and those held with bare hands. This study supports the notion that electric FHGs are a safe and effective tool for practitioners who need to temporarily immobilize fish for handling, enumeration, or performing various scientific procedures.
Received November 15, 2016; accepted February 26, 2017 Published online May 4, 2017
Whether scales reduce cutaneous evaporative water loss in lepidosaur reptiles (Superorder Lepidosauria) such as lizards and snakes has been a contentious issue for nearly half a century. Furthermore, while many studies have looked at whether dehydration affects thermal preference in lepidosaurs, far fewer have examined whether normally hydrated lepidosaurs can assess their instantaneous rate of evaporative water loss and adjust their thermal preference to compensate in an adaptive manner. We tested both of these hypotheses using three captive-bred phenotypes of bearded dragon (Pogona vitticeps) sourced from the pet trade: ‘Wild Types’ with normal scalation, ‘Leatherbacks’ exhibiting scales of reduced prominence, and scaleless bearded dragons referred to as ‘Silkbacks’. Silkbacks on average lost water evaporatively at about twice the rate that Wild Types did. Leatherbacks on average were closer in their rates of evaporative water loss to Silkbacks than they were to Wild Types. Additionally, very small (at most ∼1°C) differences in thermal preference existed between the three phenotypes that were not statistically significant. This suggests a lack of plasticity in thermal preference in response to an increase in rate of evaporative water loss, and may be reflective of a thermal ‘strategy’ as employed by thermoregulating bearded dragons that prioritises immediate thermal benefits over the threat of future dehydration. The results of this study bolster an often-discounted hypothesis regarding the present adaptive function of scales and have implications for the applied fields of animal welfare and conservation.
Wing-assisted incline running (WAIR) has been observed in bird taxa from multiple clades. Its wide phylogenetic distribution in modern birds suggests that it is an ancestral trait for class Aves. WAIR as a behaviour is speculated to predate the evolution of full-powered flight, and to have formed a behavioural and physiological stepping stone between terrestrial and aerial life. Here I report an observation of apparent WAIR in a Common Grackle (Quiscalus quiscula) photographed incidentally on a trail camera deployed in an urban backyard in Guelph, Ontario, Canada. To my knowledge this is the first documented observation of apparent WAIR for the family Icteridae. Furthermore, it highlights the value of non-systematic use of trail cameras for making unique natural history observations.
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