title: Stress response of Salmo salar (Linnaeus 1758) facing low abundance infestation of Caligus rogercresseyi (Boxshall & Bravo 2000), an object in the tank, and handling.
abstract: This study looks at how low infestation loads of adult Caligus rogercresseyi and other stressors affect the physiology of Salmo salar. Experimental fish groups were with (infested) or without (control) exposure to the parasite. The parasite cohort was followed for 78 days post-infestation (dpi), and only adult lice were observed. Additional stressors were applied at 60 and 75 dpi. The analysis included measurements of fish physiology and weight. Low-level infestations by adult C. rogercresseyi for more than 50 dpi induced moderate stress in S. salar as well as a high energy demand and increased small skin mucous cells. Threshold lice loads were identified, and above those loads, a high stress response was observed. Additional stressors altered fish physiology, inducing downregulation of the cortisol response after the first stressor and upregulation after the second stressor, but infested fish responded more strongly. Parasitism by C. rogercresseyi is energetically demanding, affecting the primary and secondary responses (e.g. cortisol and glucose levels), as well as the tertiary response (fish weight).
authors.affiliation: Programa de Doctorado en Ciencias de la Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile.
authors.forename: M P
authors.initials: MP
authors.lastname: González Gómez
authors.affiliation: Instituto de Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile.
authors.forename: S L
authors.initials: SL
authors.lastname: Marín Arribas
authors.affiliation: Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: L
authors.initials: L
authors.lastname: Vargas-Chacoff
mesh_terms: D000818:Animals; D001835:Body Weight; D033342:Copepoda / Q000502:physiology*; D015536:Down-Regulation; D004478:Ectoparasitic Infestations / Q000503:physiopathology / Q000662:veterinary*; D005260:Female; D005393:Fish Diseases / Q000469:parasitology / Q000503:physiopathology*; D006854:Hydrocortisone / Q000097:blood* / Q000235:genetics; D008297:Male; D011156:Population Density; D011897:Random Allocation; D020317:Salmo salar; D013312:Stress, Physiological
chemical_list: D006854:Hydrocortisone
keywords: Caligus rogercresseyi; Salmo salar; chronic stress; experimental infestation; fish physiology