Bioenergetics and Population Dynamics of Flannelmouth Sucker and Bluehead Sucker in Grand Canyon as Evidenced by Tag Recapture Observations

AbstractThe lower perennial corridor of the Little Colorado River in Grand Canyon, Arizona, is numerically dominated by endemic desert fishes and therefore significant for conservation of these species. From 2000 to 2012, the U.S. Fish and Wildlife Service conducted monitoring of native fishes in the Little Colorado River near its confluence with the Colorado River. The primary focus of these efforts was to estimate the spring and fall abundance of native fishes, especially the federally endangered humpback chub Gila cypha. Because humpback chub in Grand Canyon are influenced by operations of Glen Canyon Dam, our efforts provide managers of the Glen Canyon Dam Adaptive Management Program with abundance estimates and trends of humpback chub in the Little Colorado River, the most important tributary in Grand Canyon for spawning and production of this species. From 2001 to 2006, the spring abundance estimates of humpback chub ≥150 and ≥200 mm remained relatively low (≤3,419 and ≤2,002 fish, respectively), thereafter significantly increasing to highs of 8,083 and 6,250, respectively, by spring 2010. Also from 2000 to 2006, the fall abundance estimates of humpback chub were substantially below those abundances estimated after 2006. In addition, flannelmouth sucker Catostomus latipinnis and bluehead sucker Catostomus discobolus showed post-2006 increases in relative abundance, suggesting a systemwide event occurred that was beneficial to native fishes. Most of the increases of humpback chub occurred during the spring season in the reaches of the Little Colorado River between 5 and 13.57 km upstream from the confluence. Successful production of age 0 year classes of humpback chub may be partially driven by hydrograph dynamics of the Little Colorado River, whereas water temperatures and predation pressures in the mainstem Colorado River likely influence survivorship of native fishes into subadult and adult life stages.

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Population Characteristics and the Influence of Discharge on Bluehead Sucker and Flannelmouth Sucker

Copeia ◽

10.1643/ce-16-554 ◽

2017 ◽

Vol 105 (2) ◽

pp. 375-388

Author(s):

Zachary B. Klein ◽

Matthew J. Breen ◽

Michael C. Quist

Keyword(s):

Population Characteristics ◽

Bluehead Sucker ◽

Flannelmouth Sucker

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Gene flow and species delimitation in fishes of Western North America: Flannelmouth (Catostomus latipinnis) and Bluehead sucker (C. Pantosteus discobolus)

10.1101/763532 ◽

2019 ◽

Author(s):

Max R. Bangs ◽

Marlis R. Douglas ◽

Tyler K. Chafin ◽

Michael E. Douglas

Keyword(s):

North America ◽

Diagnostic Methods ◽

Assignment Test ◽

Secondary Contact ◽

Western North America ◽

Phylogenetic Species Concept ◽

Genealogical Concordance ◽

Bluehead Sucker ◽

Flannelmouth Sucker ◽

Analytical Approaches

AbstractThe delimitation of species-boundaries, particularly those obscured by reticulation, is a critical step in contemporary biodiversity assessment. It is especially relevant for conservation and management of indigenous fishes in western North America, represented herein by two species with dissimilar life-histories co-distributed in the highly modified Colorado River (i.e., Flannelmouth Sucker, Catostomus latipinnis; Bluehead Sucker, C. Pantosteus discobolus). To quantify phylogenomic patterns and examine proposed taxonomic revisions, we first employed double-digest restriction-site associated DNA sequencing (ddRAD), yielding 39,755 unlinked SNPs across 139 samples. These were subsequently evaluated with multiple analytical approaches and by contrasting life history data. Three phylogenetic methods and a Bayesian assignment test highlighted similar phylogenomic patterns in each, but with considerable difference in presumed times of divergence. Three lineages were detected in Bluehead Sucker, supporting elevation of C. P. virescens to species-status, and recognizing C. P. discobolus yarrowi (Zuni Bluehead Sucker) as a discrete entity. Admixture in the latter necessitated a reevaluation of its contemporary and historic distributions, underscoring how biodiversity identification can be confounded by complex evolutionary histories. In addition, we defined three separate Flannelmouth Sucker lineages as ESUs (Evolutionarily Significant Units), given limited phenotypic and genetic differentiation, contemporary isolation, and lack of concordance (per the genealogical concordance component of the phylogenetic species concept). Introgression was diagnosed in both species, with the Little Colorado and Virgin rivers in particular. Our diagnostic methods, and the alignment of our SNPs with previous morphological, enzymatic, and mitochondrial work, allowed us to partition complex evolutionary histories into requisite components, such as isolation versus secondary contact.

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