The effects of handling time, ambient light, and anaesthetic method, on the standardized measurement of fish colouration

• The effects of handling time, ambient light intensity, and anaesthetic method, on the collection of spectral reflectance data were assessed in two species of Malawi cichlids (Melanochromis auratus and Metriaclima zebra). Using spectrometry, colour patches were measured over 10 min, under increasing ambient light levels, and using three anaesthetic methods. As time elapsed, maximum percent reflectance (R-max) decreased across all anaesthetic methods and species, suggesting that measurements should be taken immediately after capture and anaesthetization. With increasing light intensity, R-max increased significantly, suggesting that measurements should be taken under natural ambient conditions when possible. Finally, we found that anaesthetizing fish using an ice bath produced significantly higher R-max than using either MS-222 (tricaine methanesulphonate) or clove oil ( eugenol). However, the highest proportion of ultraviolet (UV) colouration was recorded while fish were anaesthetized with clove oil. Our results highlight the variation involved in measuring fish colour patterns using two related species, and thus indicate the need for a standardized approach to collecting spectral reflectance data in fish.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

Biology

Biologi

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)