Influence of early rearing environment on water-borne cortisol and expression of stress-related genes in grass carp (Ctenopharyngodon idella)

Nowadays, lower post-release survivorship of hatchery-reared fish in natural aquatic bodies has attained great attention and research is in progress to determine the reasons for their higher mortality. It is assumed that hatchery rearing environments negatively affect the physiological stress response of the fish. Thus, understanding how rearing environments modulate this is important for the […]

Effects of different levels of environmental enrichment on the sheltering behaviors, brain development and cortisol levels of black rockfish Sebastes schlegelii

Environmental enrichment is a promising way to increase the fitness and survival of fish released for stock enhancement and biological conservation programs. However, the effects of enrichment in different studies on the fish behavior, physiology and neural development were considerably different. The present study aimed to investigate whether enrichment levels had significant effects on the […]

Perception of the ethical acceptability of live prey feeding to aquatic species kept in captivity

Previous research into public perceptions of live prey feeding has been focused on terrestrial animals. The reasons for this likely relate to the difficulty humans have in being compassionate to animals who are phylogenetically distantly related. In order to test these assumptions, the general public (two groups; one who had just visited an aquarium; and […]

Ethics and Care: For Animals, Not Just Mammals

In the last few decades, we have made great strides in recognizing ethics and providing care for animals, but the focus has been mainly on mammals. This stems from a bias of attention not only in research but predominantly in non-scientists’ attention (to ‘popular’ animals), resulting partly from discussion about and depiction of animals in […]

Magnetic orientation and magnetoreception in birds and other animals

Animals use the geomagnetic field in many ways: the magnetic vector provides a compass; magnetic intensity and/or inclination play a role as a component of the navigational ‘map’, and magnetic conditions of certain regions act as ‘sign posts’ or triggers, eliciting specific responses. A magnetic compass is widespread among animals, magnetic navigation is indicated e.g. […]

Monitoring feed amounts in goliath groupers (Epinephelus itajara) using behavioral conditioning in a large mixed species exhibit

Abstract 10.1002/zoo.20209.abs Goliath groupers (Epinephelus itajara) are large charismatic species, which are often residents in public aquaria. This study reports a novel approach to feeding techniques for three resident goliath groupers. Because of the size and depth of their exhibit, the groupers were conditioned to hand feed from aquarists. Daily food logs were recorded including […]

Morphology of the blood cells from three species of wobbegong sharks (Orectolobus species) on the east coast of New South Wales

Abstract 10.1002/zoo.20079.abs This study is the first study to describe blood cell morphology, using light microscopy, for three species of wild-caught wobbegong shark. Blood cell morphology was similar to that described previously in fish. Wobbegong sharks possess erythrocytes, at least three different morphological types of thrombocytes, lymphocytes, eosinophils, neutrophils, granuloblasts and monocytes. No basophils were […]

Group foraging versus solitary foraging efficiency in piscivorous predators: the perch, Perca fluviatilis, and pike, Esox lucius, patterns

A predator’s foraging strategy is generally described as either a sit-and-wait or an actively searching strategy. Two different behaviour patterns, often associated with these strategies, are territorial behaviour for a sit-and-wait predator, and group foraging behaviour for an actively searching predator. In a pond experiment, the effect of predator density on the efficiency of a […]

Chemical communication of handling stress in fish

We investigated whether juveniles of the nocturnal fish jundiá (Rhamdia quelen) and the diurnal fish Nile tilapia (Oreochromis niloticus) are able to chemically communicate stress to conspecifics. Groups of 8 fish were reared in tanks under recirculated water (water exchanged among all the tanks) for each species. Fish were handled in half of the tanks […]

Stress and the welfare of cultured fish

Cultured species of aquatic animals span more than five phyla. Animal welfare attention is directed towards the vertebrates because of the their neural complexity, and is currently focused on the finfish because of the size and visibility of that segment of the aquaculture industry. The characteristics of the aquatic environment and their impact on the […]