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Characteristics of Paddlefish in a Southwestern U.S. Reservoir, with Comparisons of Lentic and Lotic Populations
Author(s) -
Paukert Craig P.,
Fisher William L.
Publication year - 2001
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(2001)130<0634:copias>2.0.co;2
Subject(s) - lake ecosystem , river ecosystem , population , ecology , biology , fishery , range (aeronautics) , ecosystem , demography , materials science , sociology , composite material
We evaluated the population characteristics of a self‐sustaining population of paddlefish Polyodon spathula on the southwestern edge of its range to determine how its mortality, condition, and growth compare with those of other lentic populations and how they may differ from those of lotic populations. Paddlefish density estimates in Keystone Reservoir, Oklahoma, were similar to those in other southern self‐sustaining reservoir populations. Paddlefish catch rates varied annually; higher catches occurred in the lower reservoir reaches and in the Arkansas River arm in 1997 and 1998 but in other locations in the reservoir in 1996. Annual mortality of 27–34% was primarily from natural causes. Condition (relative weight) was high, particularly for a population near the edge of its range. Annual growth increments based on back‐calculation were not related to mean monthly air temperature or mean monthly minutes of daylight. The maximum age of paddlefish (14 years) was similar to that in other southern reservoirs. Growth rates were similar to those of other lentic populations and higher than that of lotic paddlefish collected in the Keystone Reservoir area before impoundment. Lentic populations, including that of Keystone Reservoir, had faster growth at age 0 than lotic populations, but growth rates were similar for ages 2–10, suggesting that initial growth differences produced the divergence between lentic and lotic populations. Although maximum age was not different between lentic and lotic populations, it was greater for northern waters, suggesting that latitudinal differences play a substantial role in paddlefish population characteristics. Lentic and lotic paddlefish populations may exhibit different life history characteristics (e.g., growth and mortality), but this lotic species has adapted well to reservoir environments, even near the southwestern edge of its range.