Difference between revisions of "Little Colorado River (LCR) Projects"

Spring and Fall LCR surveys (4 surveys/yr) [1]

• Uses hoopnets in the lower 13.57 river kilometers of the LCR to generate marks and get recaptures
• The LCR is divided into three contiguous reaches (Boulders, Coyote, and Salt)
• Closed Chapman Petersen mark-recapture to estimate absolute abundance of ≥150 mm and ≥200 mm humpback chub (spring and fall) and age-0 humpback chub (40-99 mm) in the fall.
• Catch per unit effort (CPUE) data = estimate relative abundance
• The two spring mark-recapture efforts (generally during April and May) are aimed to coincide with the peak of humpback chub spawning in the LCR and provides an annual estimate of the spring spawning abundance.
• The two fall mark-recapture efforts (generally during September and October) temporally expand marks and recaptures of humpback chub in the LCR, thereby strengthening other open or multistate models.
• Humpback chub, flannelmouth sucker, and bluehead sucker >150 mm are PIT tagged.
• From 2010 onward, humpback chub 40-99 mm received a Visible Implant Elastomer (VIE) tag
• Humpback chub and other fish were visually checked for the presence of the external copepod parasite (Lernaea cyprinacea), but the internal Asian fish tapeworm (Bothriocephalus acheilognathi) is no longer monitored.

Juvenile Chub Monitoring (JCM)

• Mark-Recapture (PIT tags and elastomer tags): recruitment, survival, growth, condition
• Catch per unit effort (CPUE): trends in fish too small to tag (<150 mm)
• PIT tag array: migration timing
• Near Shore Ecology (NSE) Study of the 2009-2011 fall steady flow test