Low-temperature tolerance of juvenile tarpon Megalops atlanticus

The tarpon Megalops atlanticus is a tropical to subtropical species whose pole-ward distribution is thought to be limited by low water temperatures. In the western north Atlantic Ocean juvenile tarpon occur in estuaries of the South Atlantic Bight (SAB) north of Florida near the northern limit of it...

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Bibliographic Details
Published in:Environmental biology of fishes 2017-08, Vol.100 (8), p.913-922
Main Authors: Mace, Marvin M., Haffey, Eric R., Kimball, Matthew E.
Format: Article
Language:English
Subjects:
Animal Systematics/Taxonomy/Biogeography
Aquatic habitats
Biomedical and Life Sciences
Brackishwater environment
Cold tolerance
Creeks
Current distribution
Distribution
Environment
Estuaries
Exposure
Freshwater & Marine Ecology
Life Sciences
Low temperature
Megalopae
Migration
Nature Conservation
Nursery grounds
Temperature
Temperature effects
Temperature tolerance
Tropical climate
Water temperature
Winter
Zoology
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Summary:The tarpon Megalops atlanticus is a tropical to subtropical species whose pole-ward distribution is thought to be limited by low water temperatures. In the western north Atlantic Ocean juvenile tarpon occur in estuaries of the South Atlantic Bight (SAB) north of Florida near the northern limit of its distribution, but it is currently unknown whether these individuals can survive winter, grow to maturity, and contribute to the adult population. As a first step to determine whether juvenile tarpon can survive winter conditions in the SAB, we conducted laboratory experiments to estimate minimum lethal temperatures of tarpon exposed to 1) ambient fluctuating winter water conditions and 2) a constant rate of temperature decline. Juvenile tarpon exposed to ambient winter water conditions had a mean ± standard deviation (SD) minimum lethal temperature of 13.7 ± 3.4 °C. When exposed to a constant rate of temperature decline (2 °C day −1 ), mean ± SD minimum lethal temperature (9.2 ± 0.8 °C) was lower than when tarpon were exposed to ambient fluctuating conditions. A combination of our results with all published data on the cold tolerance of juvenile tarpon resulted in an overall mean ± SD minimum lethal temperature of 12.0 ± 2.8 °C. Based on available long-term temperature records from SAB estuaries, overwinter survival of juvenile tarpon is unlikely in most aquatic habitats (e.g., tidal creeks, flats, open water). Similar to other estuarine transient fishes, juvenile tarpon likely exploit seasonably favorable nursery habitats and then migrate to other locations to overwinter.
ISSN:0378-1909
1573-5133
DOI:10.1007/s10641-017-0619-9