title: Do physical habitat complexity and predator cues influence the baseline and stress-induced glucocorticoid levels of a mangrove-associated fish?
abstract: As human populations continue to expand, increases in coastal development have led to the alteration of much of the world's mangrove habitat, creating problems for the multitude of species that inhabit these unique ecosystems. Habitat alteration often leads to changes in habitat complexity and predation risk, which may serve as additional stressors for those species that rely on mangroves for protection from predators. However, few studies have been conducted to date to assess the effects of these specific stressors on glucocorticoid (GC) stress hormone levels in wild fish populations. Using the checkered puffer as a model, our study sought to examine the effects of physical habitat complexity and predator environment on baseline and acute stress-induced GC levels. This was accomplished by examining changes in glucose and cortisol concentrations of fish placed in artificial environments for short periods (several hours) where substrate type and the presence of mangrove roots and predator cues were manipulated. Our results suggest that baseline and stress-induced GC levels are not significantly influenced by changes in physical habitat complexity or the predator environment using the experimental protocol that we applied. Although more research is required, the current study suggests that checkered puffers may be capable of withstanding changes in habitat complexity and increases in predation risk without experiencing adverse GC-mediated physiological effects, possibly as a result of the puffers' unique morphological and chemical defenses that help them to avoid predation in the wild.
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada. Electronic address: jmagel@uvic.ca.
authors.forename: Jennifer M T
authors.initials: JM
authors.lastname: Magel
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada.
authors.forename: Naomi
authors.initials: N
authors.lastname: Pleizier
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada.
authors.forename: Alexander D M
authors.initials: AD
authors.lastname: Wilson
authors.affiliation: Cape Eleuthera Institute, Rock Sound, Eleuthera, The Bahamas.
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Shultz
authors.affiliation: Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors.forename: Marilyn N
authors.initials: MN
authors.lastname: Vera Chang
authors.affiliation: Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Moon
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON K1S 5B6, Canada.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Cooke
mesh_terms: D000818:Animals; D017756:Aquaculture; D001444:Bahamas; D044822:Biodiversity; D001786:Blood Glucose / Q000032:analysis; D003463:Cues; D057217:Economic Development; D020387:Food Chain; D005938:Glucocorticoids / Q000097:blood*; D006854:Hydrocortisone / Q000097:blood*; D013312:Stress, Physiological; D023721:Tetraodontiformes / Q000097:blood / Q000254:growth & development / Q000502:physiology*; D014507:Urbanization; D053833:Wetlands
chemical_list: D001786:Blood Glucose; D005938:Glucocorticoids; D006854:Hydrocortisone
keywords: Glucocorticoids; Habitat complexity; Predation risk; Stress response