Date of Award

2-1-2022

Publication Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

Keywords

Arctic;Brain neuroanatomy;Crypt cells;Microvillous;Olfaction;Olfactory sensory neurons

Supervisor

Barbara Zielinski

Abstract

The olfactory epithelium of teleost fish contains different olfactory sensory neurons; ciliated, microvillous, and crypt cells. Using immunohistochemistry, microvillous and crypt cell olfactory neurons were visualized using calretinin and S100 antibodies respectively revealing positive immunolabelling in variety of wild non-model teleosts. These findings are significant for understanding the olfactory system of wild fish (salmonids, cyprinids, and gobiidae) and permits future research into olfactory biology to further comprehend how the olfactory system is used to assist with behaviours critical to survival and fitness. The effects of turbidity on olfactory sensory neurons in the Redside Dace, an endangered teleost extremely sensitive to environmental changes, was examined using bentonite induced turbidity. In bentonite treated fish, crypt cells were no longer observed while microvillous olfactory neurons were deformed indicating a weakened olfactory system which would greatly impact the survivability of these fish. This finding is significant as it provides new information about olfactory system degradation in environmentally turbid conditions. Brain morphology of Arctic fish (two Actinopterygii; Roughhead Grenadier, and Greenland halibut, and one Chondrichthyan; Arctic skate) was compared based on the relative size of three brain regions (telencephalon, optic lobe, and cerebellum) which is associated with behavioural patterns allowing predictions into the importance of different sensory modalities. The telencephalon was largest in Arctic skate, intermediate in Greenland halibut, and was smallest in Roughhead grenadier whereas the optic lobe was largest in Greenland halibut, intermediate in Roughhead grenadier, and smallest in Arctic skate with the cerebellum being similar across the three species demonstrating similar brain neuroanatomy proportions to Actinopterygii or Chondrichthyes living in temperate or tropical regions.

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