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Variation in drift patterns of endangered larval June suckers in the lower Provo River.
Belk, Mark1, Hanks, Joseph*,1, 1 Brigham Young University, Provo, UT
ABSTRACT- The population of June suckers (Chasmistes liorus), which is endemic to Utah lake and the lower Provo River, has experienced a dramatic decline in young-of-year recruitment for the past forty years. The Utah lake population of the Utah sucker (Catostomous ardens), a similar yet more widespread species, is also experiencing this problem. To better understand the fate of newly spawned June suckers, the Utah Division of Wildlife Resources has been collecting data on drift patterns of sucker larvae in the lower Provo River since 1997. We described patterns of larval drift for June and Utah suckers in the Provo River and compared patterns between species. Of the six years in which data were collected, the drift pattern of Utah sucker larvae in several of those years exhibited a strong trend toward the deepest, swiftest parts of the depth/flow rate gradient. In those same years, June sucker larvae were fairly evenly distributed across the gradient, with a slight trend toward shallower, slower-moving waters. Although these temporal patterns of drift did not vary within years, they did vary widely among years. Understanding these patterns of larval drift will help in conservation of this endangered species.
Key words: June sucker, larval recruitment, Chasmistes liorus, temporal drift patterns