title: Mammalian metabolic rates in the hottest fish on earth.
abstract: The Magadi tilapia, Alcolapia grahami, a small cichlid fish of Lake Magadi, Kenya lives in one of the most challenging aquatic environments on earth, characterized by very high alkalinity, unusual water chemistry, and extreme O2, ROS, and temperature regimes. In contrast to most fishes which live at temperatures substantially lower than the 36-40 °C of mammals and birds, an isolated population (South West Hot Springs, SWHS) of Magadi tilapia thrives in fast-flowing hotsprings with daytime highs of 43 °C and night-time lows of 32 °C. Another population (Fish Springs Lagoon, FSL) lives in a lagoon with fairly stable daily temperatures (33-36 °C). The upper critical temperatures (Ctmax) of both populations are very high; moreover the SWHS tilapia exhibit the highest Ctmax (45.6 °C) ever recorded for a fish. Routine rates of O2 consumption (MO2) measured on site, together with MO2 and swimming performance at 25, 32, and 39 °C in the laboratory, showed that the SWHS tilapia exhibited the greatest metabolic performance ever recorded in a fish. These rates were in the basal range of a small mammal of comparable size, and were all far higher than in the FSL fish. The SWHS tilapia represents a bellwether organism for global warming.
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1.|Department of Zoology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4.|Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Florida 33149, USA.
authors.forename: Chris M
authors.initials: CM
authors.lastname: Wood
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1.|Department of Zoology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4.|EcoTox, 2263 SW 37th Ave., #816, Miami, Florida 33145, USA.
authors.forename: Kevin V
authors.initials: KV
authors.lastname: Brix
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|SPHERE, Department of Biology, University of Antwerp, B-2020 Antwerp, Belgium.
authors.forename: Gudrun
authors.initials: G
authors.lastname: De Boeck
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming 82071, USA.
authors.forename: Harold L
authors.initials: HL
authors.lastname: Bergman
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil.
authors.forename: Adalto
authors.initials: A
authors.lastname: Bianchini
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil.
authors.forename: Lucas F
authors.initials: LF
authors.lastname: Bianchini
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Department of Zoology, University of Johannesburg, Johannesburg 2006, South Africa.
authors.forename: John N
authors.initials: JN
authors.lastname: Maina
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Department of Zoology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4.
authors.forename: Ora E
authors.initials: OE
authors.lastname: Johannsson
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|School of Dryland Agriculture Science and Technology, South Eastern Kenya University, 90200, Kitui, Kenya.
authors.forename: Geraldine D
authors.initials: GD
authors.lastname: Kavembe
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Department of Animal and Food Sciences, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Papah
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.|Kisipan M. Letura, Department of Veterinary Anatomy and Physiology, Egerton University, 20115, Njoro, Kenya.
authors.forename: Kisipan M
authors.initials: KM
authors.lastname: Letura
authors.affiliation: Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya.
authors.forename: Rodi O
authors.initials: RO
authors.lastname: Ojoo
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001481:Basal Metabolism; D001831:Body Temperature; D045482:Hot Springs; D060106:Lakes / Q000737:chemistry; D008322:Mammals; D010100:Oxygen / Q000737:chemistry; D010101:Oxygen Consumption; D013550:Swimming; D017210:Tilapia / Q000502:physiology*
chemical_list: D010100:Oxygen