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Telemetry is valuable for understanding animal ecology and assessing conservation priorities. Sturgeon species worldwide are imperiled and telemetric methods have been applied to adults, but the feasibility of using this methodology on age-0 sturgeon remains unclear. The pallid sturgeon (Scaphirhynchus albus) is a federally endangered species in the central United States and little is known about its early life ecology. The use of telemetry on age-0 pallid sturgeon would greatly increase understanding of their early life ecology. We assessed growth, survival, and swimming performance of age-0 pallid sturgeon tagged with 0.2 g, nonfunctioning radio telemetry tags to determine whether radio telemetry can be used on such small sturgeon. Tags were surgically implanted internally and attached externally, with a control group that only experienced handling. Age-0 sturgeon with internally implanted tags grew slowly and had low survival, while counterparts within the control group and those with external tags grew faster and had almost 100% survival. No differences in critical swimming speed occurred among the internally tagged, externally tagged, and control fish. We suggest externally tagging age-0 sturgeon may be possible. However, a small telemetry transmitter that uses technology (e.g., ultrasonic) which transmits well in deep rivers while maintaining a minimum tag weight and maximizing battery life is needed., INTRODUCTION Telemetry is one of the most widely used methods for examining ecological patterns of animals (Trefethen, 1956; Winter, 1996). Radio and ultrasonic transmitters are commonly used to monitor animal [...]

Understanding linkages between natal and nursery habitats is critical for conservation of riverine fishes. Scaphirhynchus sturgeons inhabiting the middle Mississippi River may originate from the Missouri or Mississippi rivers, although relative importance of these recruitment sources is unknown. We characterized the relationship between water and sturgeon fin ray Sr:Ca, verified shifts in water Sr:Ca are recorded in age-0 sturgeon fin rays, and determined whether age-0 sturgeons from the Mississippi and Missouri rivers exhibited distinct fin ray Sr:Ca signatures. Fin ray Sr:Ca of laboratory- reared fish reflected transfer from water with elevated Sr:Ca to ambient water 1 day posthatch, indicating that short-term residency in environments can be detected. Nine of 30 age-0 fish captured in the middle Mississippi River were Missouri River emigrants. Four of these emigrants originated in the upper portion of the lower Missouri River ([greater than or equal to] 589 km upstream from its mouth), where water Sr:Ca is higher compared with the lowermost section of the Missouri River and the Mississippi River. Twenty-five of 30 fish collected from the lowermost section of the Missouri River originated within this river segment; the remainder originated upriver. Fin ray Sr:Ca enables identification of natal river segment for age-0 sturgeons and contributions of river segments to sturgeon recruitment. La conservation des poissons des riviere requiert une comprehension des liens entre les habitats de naissance et de nourricerie. Les esturgeons Scaphirhynchus qui habitent le cours moyen du Mississippi peuvent provenir de la riviere Missouri ou du Mississippi, mais l'importance relative de ces sources de recrutement est inconnue. Nous caracterisons la relation entre les rapports Sr:Ca de l'eau et des rayons de nageoires des esturgeons, verifions si les changements dans le Sr: Ca de l'eau s'inscrivent dans les rayons de nageoire des esturgeons d'age 0 et determinons si les esturgeons du Mississippi et du Missouri portent des signatures Sr:Ca distinctes dans leurs rayons de nageoires. Le Sr:Ca des rayons des nageoires de poissons eleves en laboratoire reflete le transfert de l'eau a Sr:Ca eleve a de l'eau ambiante 1 jour apres l'eclosion, ce qui indique qu'une residence de courte duree dans un environnement peut etre detectee. Neuf de 30 poissons d'age 0 captures dans le cours moyen du Mississippi etaient des immigrants provenant du Missouri. Quatre de ces immigrants venaient de la portion superieure du cours inferieur du Missouri (≥589 km de son embouchure) ou le Sr:Ca de l'eau est plus eleve que dans la section plus en aval du Missouri et dans le Mississippi. Vingt-cinq des 30 poissons recoltes dans la section la plus en aval du Missouri provenaient de ce segment de riviere; les autres venaient de l'amont. Le Sr:Ca des rayons de nageoires permet d'identifier le segment de riviere de naissance chez les esturgeons d'age 0, ainsi que les contributions des differents segments de la riviere au recrutement des esturgeons. [Traduit par la Redaction], Introduction Understanding interrelationships among habitats used by fishes for spawning, nursery, growth, and refuge is paramount for conservation efforts (Schlosser 1995; Fausch et al. 2002). Knowledge of geographic areas that [...]

Because the shovelnose sturgeon (Scaphirhynchus platorynchus) population in the Middle Mississippi River (MMR) between Cairo, IL and St. Louis, MO (RKM 0-320) appears to be declining, we must understand dietary needs to help assess its conservation status. Diet is linked to growth, condition and reproduction and reflects population state. Thus, we quantified diets of adult shovelnose sturgeon monthly using gill nets (5.08-cm bar mesh) during Jan. 9005 through Nov. 2005 at three sites on the MMR (RKM: 201-198; 191-188, and RKM 127-124). Stomachs were removed from adult shovelnose sturgeon (winter n = 71; spring n = 163; summer n = 149; fall n = 179; fork length mean = 617 mm; standard deviation = 64.57). Overall, prey items occurred in less than 30% (n = 170) of shovelnose sturgeon stomachs. Dominant prey items throughout all seasons (winter, spring, summer and fall) were Chironomidae, Hydropsychidae, Ephemeridae and Corophiidae respectively. Corophiidae is an exotic amphipod that has not previously been documented in the MMR. The total abundance of diet items was high during winter through spring and low during summer through fall. Ephemeridae dominated in winter. Hydropsychidae was the most important prey item during spring through summer. Corophiidae dominated diets in the fall. Temperature and perhaps low river discharge appeared to affect prey consumed, with high temperatures and low discharge during summer through fall causing low energy intake, lowered condition and likely poor growth. Conservation efforts that provide flow refugia may improve energy intake and likely enhance shovelnose sturgeon populations in the MMR., INTRODUCTION Due to commercial harvest and habitat degradation worldwide, sturgeon numbers have been declining for nearly 100 y (Keenlyne, 1997; Shuman, 2003). Mature female sturgeon are selectively harvested for caviar, [...]

Recruitment is one of the most important dynamic rate functions (i.e., recruitment, growth, and mortality). Often, recruitment can be heavily dependent on overwinter survival. Wintertime presents thermal and metabolic challenges to fish. Studies have suggested that overwinter survival and mortality is correlated to lipid content before entering winter. Inadequate lipid reserves are related to poor condition and may lead to overwinter mortality. Young fish need to accumulate adequate lipid reserves before entering winter. In the Mississippi River, where silver carp Hypophthalmichthys moltrix Valenciennes, 1844 are hyper abundant, silver carp are not experiencing recruitment issues. As such, we evaluated lipid levels and size as potential silver carp recruitment regulators. Silver carp were collected by the Long Term Resource Monitoring element in 2015 on the middle Mississippi River using mini fyke nets; total lengths ranged from 34-177 mm. Lipid levels of whole carp were determined using the phosphovanillin assay. No difference in lipid levels (mg/g) was observed between spring and fall fishes. Additionally, we observed no relation between total length and lipid levels. Size structure did not significantly differ between fall age-0 and spring age-1 silver carp. Our results suggest there may not be a size dependent overwinter mortality/survival in silver carp in the middle Mississippi River. Additionally, lipids may not be a driving factor in overwinter mortality/survival. Our research suggests silver carp in the Mississippi River basin do not follow most early life history paradigms and may explain the successful nature of the silver carp invasion. [ABSTRACT FROM AUTHOR]

Studies have demonstrated the importance of the synergistic relationship between large rivers and adjacent floodplain connectivity. The majority of large rivers and their associated floodplain have been isolated through a series of expansive levee systems. Thus, evaluations of the relative importance of floodplain connectivity are limited due to the aforementioned anthropogenic perturbations. However, persistent elevated river levels during spring 2011 at the confluence of the Mississippi River and Ohio River prompted the U.S. Army Corps of Engineers to create large gaps in the levee system producing an expansive floodplain (i.e. the New Madrid Floodway). Specifically, the New Madrid Floodway (approximately 475 km2) in southeast Missouri was created to divert part of the Mississippi River flow during catastrophic floods and thus alleviate flood risk on nearby population centers. Given the historic flooding of 2011, the floodway was opened and provided an unprecedented opportunity to evaluate the influence of floodplain inundation on fish species diversity, relative abundance, and growth. We sampled the floodplain and the adjacent river at three stratified random locations with replication biweekly from the commencement of inundation (late May) through early October. Overall, we found that species diversity, relative abundance, and growth were higher in the floodplain than the main river. Our data support previous examinations, including those outside North America, that suggest floodplain inundation may be important for riverine fishes. Given these apparent advantages of floodplain inundation, restoration efforts should balance benefits of floodplain inundation while safeguarding priority needs of humans. [ABSTRACT FROM AUTHOR]

Ultrasonic telemetry allows fisheries management biologists to evaluate habitat use and movement patterns of fish. The physical condition of the fish is altered by surgical tag implantation into the body cavity, and many studies have been conducted to quantify effects on fish behavior and health following surgery. However, few studies have evaluated whether topical antibiotic application to the incision site minimizes long-term effects associated with recovery following surgery. Therefore, we quantified how common surgical procedures coupled with a topical antibiotic affected growth and survival of hybrid striped bass (Morone chrysops * Morone saxatilis). Growth and survival were assessed over an eight week period among four treatment groups: 1) control/no surgery, 2) sham surgery, 3) surgical tag implantation, or 4) surgical tag implantation with a waterproof topical antibiotic; all reared in a controlled environment. Growth did not differ among treatments; however, survival differed with 100% survival occurring in the control and the tag plus topical antibiotic treatments. In surgical treatments without topical antibiotic use, survival was 95% with sham surgery and 85% with surgery plus tag. Inflammation was reduced at the incision site when the waterproof topical antibiotic was used. Ultimately, these data suggest application of topical antibiotics may increase survival and thus reduce biases associated with mortality during telemetry studies. [ABSTRACT FROM AUTHOR]