Histology of Alarm Substance Cells in Relation to Parasite Load and Fish Size for Hornyhead Chub (Nocomis biguttatus)

Abstract

Alarm substance cells (ASC) found in the epidermis of many freshwater fish species release chemicals when ruptured, which have generally been thought to alert nearby potential prey. Competing hypotheses propose a function of these cells in the immune system, prompting this study using wild, preserved specimens of the Hornyhead Chub (Nocomis biguttatus) affected with a black spot parasite (Neascus pyriformes). Previous work has shown that in the predatory minnow, Creek Chub, variability in ASC densities is associated with size, mucus cell density and epidermal thickness. This study attempted to assess these relationships in the non-predatory minnow, Hornyhead Chub.