Individuality really matters for fish welfare
Animal welfare science started to gain ground in the 1960s (Duncan 2006), especially after the publication of the famous book Animal Machines in 1964 by Ruth Harrison. this book exposed several farm practices that were causing suffering for terrestrial farmed animals, which later basically culminated in the official publication of the famous five freedoms in […]
Mirror, mirror on the wall… How tank material and the presence of “enrichments” affect competition and agonism in zebrafish (Danio rerio)
Despite generations of rearing in a laboratory environment, zebrafish (Danio rerio) retain innate preferences for environmental features that mimic their natural habitat (e.g. plants and gravel), but the effects of such preferred housing conditions on agonism are poorly understood. In this study, we worked with > 450 fish in 41 tanks to test two competing […]
Observations on the use of passive integrated transponder (PIT) tags in teleosts and elasmobranchs at a public aquarium, 728 cases, 2007–2020
Between 2007 and 2020 at New England Aquarium, Boston, MA, USA, we implanted passive integrated transponder (PIT) tags into 728 fish representing 105 teleost and elasmobranch species to identify animals as individuals. At the time of retrospective data analysis, mean longevity interval (median, range) after tag placement for animals that remained alive (n = 236) was 4.7 […]
A Comparative Study on Two Territorial Fishes: The Influence of Physical Enrichment on Aggressive Behavior
Intraspecific aggression is detrimental to body/fin damage, physiological stress, and other problems in aquaculture. Environmental enrichment has been proposed to have positive effects on fish aggressive behavior, physiological stress, and fish welfare, but there are mixed results. Here, we examine the impact of physical enrichment levels (i.e., the intensity of physical enrichment) on aggression in […]
Tank cleaning temporarily increases stress and decreases affiliative behavior in zebrafish
Small, tropical fish are popular companion animals and constitute a major proportion of the vertebrates used in scientific research, but little is known about how they are affected by routine husbandry practices. Manual tank cleanings are a common and potentially stressful maintenance procedure that involves siphoning out a substantial volume of tank water, ‘vacuuming’ the […]
Physical enrichment research for captive fish: time to focus on the DETAILS
Growing research effort has shown that physical enrichment (PE) can improve fish welfare and research validity. However, the inclusion of PE does not always result in positive effects and conflicting findings have highlighted the many nuances involved. Effects are known to depend on species, and life stage tested, but effects may also vary with differences […]
Increase in environmental temperature affects exploratory behaviour, anxiety and social preference in Danio rerio
The aim of this work is to investigate the effect of a temperature increase on the behaviour of adult zebrafish (Danio rerio) maintained for 21 days at 34 °C (treatment) and 26 °C (control). The temperatures chosen are within the vital range of zebrafish and correspond to temperatures that this species encounters in the natural environment. Previous […]
Aggressive encounters lead to negative affective state in fish
Animals show various behavioural, neural and physiological changes in response to losing aggressive encounters. Here, we investigated affective state, which are emotion-like processes influenced by positive or negative experiences, in a territorial fish following aggressive encounters and explore links to bold/shy behavioural traits. Eighteen 15-month old Murray cod (Maccullochella peelii) received three tests in order […]
The Ethical Assessment of Touch Pools in Aquariums by Means of the Ethical Matrix
Touch pools are popular open-topped fish tanks often found in aquariums where visitors may interact with animals, by touching and sometimes even feeding them, for educational and recreational purposes. However, although animal interactions are becoming increasingly popular in recent years, the welfare impact on the animals and the educational effectiveness of such interactions is under […]
A Standardized Protocol for Preference Testing to Assess Fish Welfare
Animal welfare assessment techniques try to take into consideration the specific needs and wants of the animal in question. Providing enrichment (the addition of physical objects or conspecifics in the housing environment) is often a way to give captive animals the opportunity to choose who or what they interact with and how they spend their […]