scholarly journals Intraspecific variation in migration timing of green sturgeon in the Sacramento River system

2021 ◽  
Author(s):  
Scott F. Colborne ◽  
Lawrence W. Sheppard ◽  
Daniel R. O’Donnell ◽  
Daniel C. Reuman ◽  
Jonathan A. Walter ◽  
...  
Keyword(s):  
Life History ◽  
Movement Patterns ◽  
River System ◽  
Bimodal Distribution ◽  
Sacramento River ◽  
Green Sturgeon ◽  
Life History Variation ◽  
Acipenser Medirostris ◽  
Migration Timing ◽  
Timing Of Migration

AbstractBackgroundUnderstanding movement patterns of anadromous fishes is critical to conservation management of declining wild populations and preservation of habitats. Yet, infrequent observations of individual animals fundamentally constrain accurate descriptions of movement dynamics.MethodsIn this study, we synthesized over a decade (2006–2018) of acoustic telemetry tracking observations of green sturgeon (Acipenser medirostris) in the Sacramento River system to describe major anadromous movement patterns.ResultsWe observed that green sturgeon exhibited a unimodal in-migration during the spring months but had a bimodal distribution of out-migration timing, split between an ‘early’ out-migration (32%) group during May - June, or alternatively, holding in the river until a ‘late’ out-migration (68%), November - January. Focusing on these out-migration groups, we found that river discharge, but not water temperature, may cue the timing of migration, and that fish showed a tendency to maintain out-migration timing between subsequent spawning migration events.ConclusionsWe recommend that life history descriptions of green sturgeon in this region reflect the distinct out-migration periods described here. Furthermore, we encourage the continued use of biotelemetry to describe migration timing and life history variation, not only this population but other green sturgeon populations and other species.

Migration of green sturgeon, Acipenser medirostris, in the Sacramento River

2008 ◽  
Vol 84 (3) ◽  
pp. 245-258 ◽  
Author(s):  
Joseph C. Heublein ◽  
John T. Kelly ◽  
Carlos E. Crocker ◽  
A. Peter Klimley ◽  
Steven T. Lindley
Keyword(s):  
Sacramento River ◽  
Green Sturgeon ◽  
Acipenser Medirostris

scholarly journals Integrating physiological data with the conservation and management of fishes: a meta-analytical review using the threatened green sturgeon (Acipenser medirostris)

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Essie M Rodgers ◽  
Jamilynn B Poletto ◽  
Daniel F Gomez Isaza ◽  
Joel P Van Eenennaam ◽  
Richard E Connon ◽  
...  
Keyword(s):  
Life History ◽  
Elevated Temperatures ◽  
Swimming Performance ◽  
Yolk Sac ◽  
Physiological Data ◽  
Future Research ◽  
Green Sturgeon ◽  
Acipenser Medirostris ◽  
Life History Stages ◽  
Management Actions

Abstract Reversing global declines in the abundance and diversity of fishes is dependent on science-based conservation solutions. A wealth of data exist on the ecophysiological constraints of many fishes, but much of this information is underutilized in recovery plans due to a lack of synthesis. Here, we used the imperiled green sturgeon (Acipenser medirostris) as an example of how a quantitative synthesis of physiological data can inform conservation plans, identify knowledge gaps and direct future research actions. We reviewed and extracted metadata from peer-reviewed papers on green sturgeon. A total of 105 publications were identified, spanning multiple disciplines, with the primary focus being conservation physiology (23.8%). A meta-analytical approach was chosen to summarize the mean effects of prominent stressors (elevated temperatures, salinity, low food availability and contaminants) on several physiological traits (growth, thermal tolerance, swimming performance and heat shock protein expression). All examined stressors significantly impaired green sturgeon growth, and additional stressor-specific costs were documented. These findings were then used to suggest several management actions, such as mitigating salt intrusion in nursery habitats and maintaining water temperatures within optimal ranges during peak spawning periods. Key data gaps were also identified; research efforts have been biased towards juvenile (38.1%) and adult (35.2%) life-history stages, and less data are available for early life-history stages (embryonic, 11.4%; yolk-sac larvae, 12.4%; and post yolk-sac larvae, 16.2%). Similarly, most data were collected from single-stressor studies (91.4%) and there is an urgent need to understand interactions among stressors as anthropogenic change is multi-variate and dynamic. Collectively, these findings provide an example of how meta-analytic reviews are a powerful tool to inform management actions, with the end goal of maximizing conservation gains from research efforts.

scholarly journals Movement patterns and home range size of tigerfish (Hydrocynus vittatus) in the Incomati River system, South Africa

Koedoe ◽  
2018 ◽  
Vol 60 (1) ◽  
Author(s):  
Francois Roux ◽  
Gert Steyn ◽  
Clinton Hay ◽  
Ina Wagenaar
Keyword(s):  
Life History ◽  
Home Range ◽  
Large Scale ◽  
Specific Activity ◽  
Movement Patterns ◽  
River System ◽  
Home Range Size ◽  
Range Size ◽  
Management Policy ◽  
Fish Movement

Historical data suggested that the tigerfish (Hydrocynus vittatus) of the Incomati River migrates upstream and downstream as part of their life history. It has been suggested that this movement was a prerequisite for successful spawning in inundated floodplains in Mozambique. Recent advances in aquatic radio telemetry provided a reliable mechanism to monitor fish movement and increase knowledge of the ecology of tigerfish. From 04 January 2003 to 22 December 2003, 41 tigerfish in the Incomati River system were fitted with radio transmitters to record movement patterns and estimate home range size. On average, each fish was tracked 72 times, and the total number of fixes was 2971 over the study period, including 1322 summer fixes and 1649 winter fixes. The mean longest distance travelled by tigerfish was 730 m (range = 75 m to 3200 m). The home range size varied between individual fish, but on average fish stayed within a defined home range of 48 846 m2. Tigerfish showed high site fidelity to specific habitats within specific activity zones and movement occurred primarily within these defined zones. Differences in movement pattern, longest distance travelled and home range size could not be attributed to the sex or size of the fish. No large-scale movement patterns associated with specific life history activity were observed; thus, previous reports of large-scale downstream migrations and spawning migrations appear to be invalid. The presence of weirs in the study area impedes free fish movement as these weirs create migration obstructions.Conservation implications: River regulation such as damming, water abstraction, obstructive barriers and channel modification may have a detrimental impact on the survival strategy of this species. Implementation of these results in a management policy will provide a reliable basis for species specific requirements such as upstream reservoir release management; minimum flow volumes required for downstream ecosystem maintenance and management and planning of structures obstructing natural flow.

scholarly journals “And if you gaze long into an abyss, the abyss gazes also into thee”: four morphs of Arctic charr adapting to a depth-gradient in Lake Tinnsjøen

2019 ◽  
Author(s):  
Kjartan Østbye ◽  
Marius Hagen Hassve ◽  
Ana-Maria Tamayo Peris ◽  
Mari Hagenlund ◽  
Thomas Vogler ◽  
...  
Keyword(s):  
Life History ◽  
Reproductive Isolation ◽  
Adaptive Radiation ◽  
Arctic Charr ◽  
River System ◽  
Ecological Speciation ◽  
The Arctic ◽  
Life History Trait ◽  
Life History Variation ◽  
Microsatellite Variation

AbstractBackgroundThe origin of species is a central topic in biology aiming at understanding mechanisms, level and rate of diversification. Ecological speciation is an important driver in adaptive radiation during post-glacial intra-lacustrine niche diversification in fishes. The Arctic charr Salvelinus alpinus L. species complex in the Northern hemisphere freshwater systems display huge morphological and life history divergence in lakes with one or several morphs present, thus offering a unique opportunity to address ongoing speciation mechanisms.We studied Arctic charr in Lake Tinnsjøen by fishing in four nominal lake habitats (pelagial, littoral, shallow-moderate profundal, and deep-profundal habitats) down to 350 meters depth. Research topics addressed were; (1) to illuminate Holarctic phylogeography and lineages colonizing Lake Tinnsjøen, (2) to estimate reproductive isolation of morphs or fish using unbiased methods, and (3) to document eco-morphological and life history trait divergence. Also, we compared Lake Tinnsjøen with four Norwegian outgroup populations of Arctic charr.ResultsFour field-assigned morphs were identified in Lake Tinnsjøen; the planktivore morph in all habitats except deep-profundal, the dwarf morph in shallow-moderate profundal, the piscivore morph in shallow-moderate profundal (less in littoral and deep-profundal), and an undescribed new morph – the abyssal morph in the deep-profundal only. The morphs displayed extensive life history variation based on age and size patterns. A moderate to high concordance was observed between field-assigned morphs and four unbiased genetic clusters obtained from microsatellite variation. MtDNA suggested the occurrence of two minor endemic clades in Lake Tinnsjøen likely originating from one widespread colonizing clade in the Holarctic. All morphs were genetically differentiated at microsatellites (FST: 0.12-0.20; with some ongoing gene flow among morphs, and for most mtDNA comparisons (FST: 0.04-0.38). Analyses of Norwegian outgroup lakes implied colonization from a river system below Lake Tinnsjøen.ConclusionOur findings suggest post-glacial adaptive radiation of one colonizing mtDNA lineage with divergent niche specialization along a depth-temperature-productivity-pressure gradient. Concordance between reproductive isolation and the realized habitat of the morphs imply that ecological speciation may be the mechanism of divergence. Particularly novel is the extensive morph diversification with depth into the often unexplored deep-water profundal habitat, suggesting we may have systematically underestimated biodiversity present in lakes.

Behavior, movements, and habitat use of adult green sturgeon, Acipenser medirostris, in the upper Sacramento River

2013 ◽  
Vol 97 (2) ◽  
pp. 133-146 ◽  
Author(s):  
Michael J. Thomas ◽  
Matthew L. Peterson ◽  
Eric D. Chapman ◽  
Alex R. Hearn ◽  
Gabriel P. Singer ◽  
...  
Keyword(s):  
Habitat Use ◽  
Sacramento River ◽  
Green Sturgeon ◽  
Acipenser Medirostris
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