Difference between revisions of "Aggregations Projects"
From Glen Canyon Dam AMP
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adults.” (Valdez and Ryel 1995) | adults.” (Valdez and Ryel 1995) | ||
| − | ==There are | + | ==There are six recognized aggregations below Glen Canyon Dam: [https://pubs.usgs.gov/of/2016/1177/ofr20161177.pdf] == |
| − | *30 Mile | + | *30 Mile (RM 29.8-36.3) |
| − | *Little Colorado River inflow | + | *Little Colorado River inflow (RM 57.0-77.2) |
| − | + | *Shinumo Creek inflow (RM 107.8-110.0) | |
| − | *Shinumo Creek inflow | + | *Middle Granite Gorge (RM 125.0-129.7) |
| − | + | *Havasu Creek inflow (RM 155.8-159.2) | |
| − | *Middle Granite Gorge | + | *Pumpkin Spring (RM 212.5-216.0) |
| − | *Havasu Creek inflow (RM | + | |
| − | *Pumpkin Spring (RM 212.5-216) | + | |
Humpback chub are also caught outside of the aggregations. Samples are also being collected at: | Humpback chub are also caught outside of the aggregations. Samples are also being collected at: | ||
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*Fall Canyon (RM 210-212) | *Fall Canyon (RM 210-212) | ||
*Bridge City (RM 237-244) | *Bridge City (RM 237-244) | ||
| − | *Spencer & Surprise (RM 245-249.5) | + | *Spencer & Surprise (RM 245-249.5) [https://www.usbr.gov/uc/rm/amp/twg/mtgs/17jan26/AR12_Young.pdf] |
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| − | *'''Aggregation Sampling:''' | + | *'''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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| + | '''2020''' | ||
| + | *[[Media:Van Haverbeke et al. 2020 (2019 Aggregation Report).pdf| Van Haverbeke et al., 2020. Monitoring Humpback Chub in the Colorado River, Grand Canyon during fall 2019. U.S. Fish and Wildlife Service, Flagstaff, AZ. USFWS Document No. USFWS-AZFWCO-20-03. 39 pp.]] | ||
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| + | '''2019''' | ||
| + | *[[Media:Aggregation Report 2018 FINAL.pdf| Monitoring Humpback Chub Aggregations in the Colorado River, Grand Canyon during fall 2018]] | ||
'''2017''' | '''2017''' | ||
Latest revision as of 16:59, 10 December 2020
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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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