Juvenile Atlantic and Shortnose Sturgeons (Family: Acipenseridae) Have Different Hematological Responses to Acute Environmental Hypoxia

• Published in: Physiological and biochemical zoology 2005-11, Vol.78 (6), p.916-925
• Main Authors: Baker, D. W., Wood, A. M., Kieffer, J. D.
• Format: Article
• Language: English
• Subjects: Acipenser; Acipenser brevirostrum; Acipenseridae; Analysis of Variance; Animals; Blood; Blood Glucose; Blood plasma; Chlorides - blood; Fish Diseases - blood; Fish Diseases - physiopathology; Fishes; Hematocrit; Hemoglobins; Hemoglobins - metabolism; Hydrocortisone - blood; Hypoxia; Hypoxia - blood; Hypoxia - physiopathology; Hypoxia - veterinary; Lactates; Lactic Acid - blood; Oxygen; Oxygen - metabolism; Pulmonary Ventilation - physiology; Sodium - blood; Species Specificity; Sturgeon; Time Factors; Ventilation systems
• ISSN: 1522-2152; 1537-5293
• DOI: 10.1086/432860

Experiments were conducted to determine the behavioral and physiological responses to acute hypoxic challenges in Atlantic (Acipenser oxyrinchus) and shortnose (Acipenser brevirostrum) sturgeons. We measured the ventilatory rate following a 45‐mmHg hypoxic challenge, as well as a variety of hematological parameters, including O2transport and hormonal, ionic, and metabolic variables, following a 1‐h exposure to either 75‐ or 30‐mmHg hypoxic challenges. Compared to fish in normoxic conditions (Pwo 2150 mmHg), juveniles of both species increased their ventilatory rate by approximately 40% when exposed to a 1‐h challenge at 45 mmHg Pwo 2. Hematological variables (e.g., hematocrit, hemoglobin, and Na+and Cl−levels) did not change substantially following a 1‐h challenge at 75 mmHg Pwo 2. Conversely, a severe hypoxic challenge of 30 mmHg caused changes in several hematological variables (e.g., whole blood glucose and plasma cortisol and lactate levels). Most of these hematological parameters returned to prehypoxic levels within 2 h. Severe environmental hypoxia elicited the same basic pattern of response in both species; however, maximal plasma lactate levels were higher in Atlantic sturgeons, and maximal cortisol levels were higher in shortnose sturgeons. Whether these species differences are related to dissimilar hypoxia‐tolerance, ecological, and/or endocrinological characteristics between these two species is not entirely clear.