Difference between revisions of "Aggregations Projects"
From Glen Canyon Dam AMP
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| − | *'''Aggregation Sampling:''' 1 trip/year (reduced from two trips/year in FY13-14). Lead by USFWS. | + | *'''Aggregation Sampling:''' Electrofishing at the 6 aggregation sites specified above since 2010. 1 trip/year (reduced from two trips/year in FY13-14). Lead by USFWS. |
| − | *'''System Wide Electrofishing:''' | + | *'''System Wide Electrofishing:''' Collect longterm monitoring data of native and nonnative fish outside of the LCR/NO reaches. 3 trips: 2 spring/summer, 1 in fall since 2000. Near shore electrofishing. New in 2016: Baited hoop nets and extended below Diamond to Pierce. Lead by AZDGF. |
| + | *'''Otolith Microchemistry:''' Determine sources of humpback chub recruitment. | ||
| + | *'''Portable PIT-tag antennas:''' Locate additional aggregations. | ||
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Revision as of 13:58, 6 June 2017
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Aggregation:“A consistent and disjunct group of fish with no significant exchange of individuals with other aggregations, as indicated by recapture of PIT‐tagged juveniles and adults and movement of radio‐tagged adults.” (Valdez and Ryel 1995) There are six recognized aggregations below Glen Canyon Dam: [1]
Humpback chub are also caught outside of the aggregations. Samples are also being collected at:
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There have been substantial increases in the captures of humpback chub in aggregation sampling since 2014, particularly at the LCR, Havasu, Pumpkin Spring, and in Western Grand Canyon. [3] [4]   Possible drivers for the increases of humpback chub in Western Grand CanyonImmigration2016 Aggregation sampling
Temperature: consistently >19C in Western Grand Canyon [9]
Local Recruitment2016 System Wide Electrofishing (and hoopnetting)
Below RM 220: 3/146 recaptures (2%)
Translocations: Population may be reaching a critical mass |
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