Kevin M. Kappenman

Effect of Temperature on Growth, Condition, and Survival of Juvenile Shovelnose Sturgeon

Abstract Water temperature plays a key role in determining the persistence of shovelnose sturgeon Scaphirhynchus platorynchus in the wild and is a primary factor affecting growth both in the hatchery and in natural waters. We exposed juvenile shovelnose sturgeon to temperatures from 8°C to 30°C for 87 d to determine the effect of temperature on growth, condition, feed efficiency, and survival. Growth occurred at temperatures from 12°C to 30°C; the optimal temperature predicted by regression analysis was 22.4°C, and the minimum temperature needed for growth was greater than 10.0°C. The maximum feed efficiency predicted by regression analysis was 24.5% at 21.7°C, and condition factor was highest in the 18°C treatment. Mortality was significantly higher at 28°C and 30°C than at lower temperatures but less than 10% across the thermal regimes tested and 0% at 14-18°C. Mortality was observed at and below 12°C, suggesting that extended periods of low temperature may deplete energy reserves and lead to higher mor...

Broadening the Regulated-River Management Paradigm: A Case Study of the Forgotten Dead Zone Hindering Pallid Sturgeon Recovery

The global proliferation of dams within the last half century has prompted ecologists to understand the effects of regulated rivers on large-river fishes. Currently, much of the effort to mitigate the influence of dams on large-river fishes has been focused on downriver effects, and little attention has been given to upriver effects. Through a combination of field observations and laboratory experiments, we tested the hypothesis that abiotic conditions upriver of the dam are the mechanism for the lack of recruitment in Pallid Sturgeon (Scaphirhynchus albus), an iconic large-river endangered species. Here we show for the first time that anoxic upriver habitat in reservoirs (i.e., the transition zone between the river and reservoir) is responsible for the lack of recruitment in Pallid Sturgeon. The anoxic condition in the transition zone is a function of reduced river velocities and the concentration of fine particulate organic material with high microbial respiration. As predicted, the river upstream of th...

Ghost Nets in the Columbia River: Methods for Locating and Removing Derelict Gill Nets in a Large River and an Assessment of Impact to White Sturgeon

Abstract Lost gill nets, known as ghost nets, represent a threat to aquatic species. Gill nets have been in use in the Columbia River commercial fishery since the mid-1800s, and a number of gill nets continue to be lost each year. We designed a study to investigate the effect of lost nets in the Columbia River. For this study, we developed methods to recover nets and evaluated the use of side-scan sonar (SSS) to locate nets. Grappling in known commercial fishing areas effectively removed nets and was more efficient than relying on SSS to direct recovery efforts. In 154 grapple tows, we recovered 33 nets containing 126 white sturgeon Acipenser transmontanus. Newly lost nets caught significantly more white sturgeon than older nets. Recovered nets at large less than 1 year were responsible for 63% of the total catch, nets at large 1–4 years captured 24%, and nets at large more than 4 years captured 13%. We determined that approximately 10 nets are lost each year, estimated that lost nets have a life span of ...

Thermal Requirements of the Bonytail (Gila elegans): Application to Propagation and Thermal-Regime Management of Rivers of the Colorado River Basin

Abstract We performed experimental trials on hatchery-reared juvenile bonytails (Gila elegans) using the acclimated-chronic-exposure method. Bonytails were exposed to 8–30°C for 112 days to determine effects on growth, condition factor, composition of body, and survival. Survival was ≥98% for all treatments. The predicted temperature was 25.9°C for maximum gain in weight and 14.2°C for zero gain. Temperatures <14°C depressed growth, 14–20°C provided incremental growth, and 22–26°C allowed accelerated growth. We hypothesize that temperatures during propagation and seasonal temperatures of rivers that are 22–26°C, or both, would maximize growth of juveniles and might promote higher survival because bonytails would be less vulnerable to predation, and have greater energy reserves and increased metabolic efficiency.

Determination of Upper Temperature Tolerance in June Sucker Larvae: Is the Transition to Utah Lake Temperatures a Recruitment Bottleneck?

Abstract The June sucker Chasmistes liorus is an endangered adfluvial fish species that is endemic to the Utah Lake basin. This species remains endangered due to a lack of recruitment. Anthropogenic changes to June sucker lotic and lentic habitat has likely led to recruitment failure. Changes to Utah Lake include increased water temperature, increased turbidity, and eutrophic and saline conditions. The remaining spawning habitat for June suckers in the Provo River has experienced flow, temperature, and channelization modifications. We tested the hypothesis that recruitment failure is caused by a thermal shock that occurs when larvae are transported in the drift out of the Provo River (12–19°C) and into Utah Lake (17–25°C). We used two laboratory methods—direct transfer and acclimated chronic exposure (ACE)—to determine (1) the upper lethal temperature (ULT) and (2) the acute and chronic mortality associated with larval exposure to an acute thermal shock. The ULT of larvae acclimated to 16°C was 33°C. Surv...

Thermal tolerance of meltwater stonefly Lednia tumana nymphs from an alpine stream in Waterton–Glacier International Peace Park, Montana, USA

Abstract. Global climate change threatens to affect negatively the structure, function, and diversity of aquatic ecosystems worldwide. In alpine systems, the thermal tolerances of stream invertebrates can be assessed to understand better the potential effects of rising ambient temperatures and continued loss of glaciers and snowpack on alpine stream ecosystems. We measured the critical thermal maximum (CTM) and lethal temperature maximum (LTM) of the meltwater stonefly (Lednia tumana), a species limited to glacial and snowmelt-driven alpine streams in the Waterton–Glacier International Peace Park area and a candidate for listing under the US Endangered Species Act. We collected L. tumana nymphs from Lunch Creek in Glacier National Park, Montana (USA) and transported them to a laboratory at the University of Montana Flathead Lake Biological Station, Polson, Montana. We placed nymphs in a controlled water bath at 1 of 2 acclimation temperatures, 8.5 and 15°C. We increased water temperature at a constant rate of 0.3°C/min. We calculated the average CTM and LTM (± SD) for each acclimation temperature and compared them with Students t-tests. Predicted chronic temperature maxima were determined using the ⅓ rule. Mean LTMs were 32.3 ± 0.28°C and 31.05 ± 0.78°C in the 8.5 and 15°C acclimation treatments, respectively. CTM and LTM metrics were lower in the 15 than in the 8.5°C acclimation treatment, but these differences were not statistically significant (p > 0.05). The predicted chronic temperature maxima were 20.6 and 20.2°C for the 8.5 and 15°C acclimation treatments, respectively. More research is needed on the effects of chronic exposures to rising stream temperatures, but our results can be used to assess the potential effects of warming water temperatures on L. tumana and other aquatic macroinvertebrates in alpine ecosystems.

Evaluation of swimming performance for fish passage of longnose dace Rhinichthys cataractae using an experimental flume

The swimming performance of longnose dace Rhinichthys cataractae, the most widely distributed minnow (Cyprinidae) in North America, was assessed in relation to potential passage barriers. The study estimated passage success, maximum ascent distances and maximum sprint speed in an open-channel flume over a range of water velocities and temperatures (10·7, 15·3 and 19·3° C). Rhinichthys cataractae had high passage success (95%) in a 9·2 m flume section at mean test velocities of 39 and 64 cm s-1 , but success rate dropped to 66% at 78 cm s-1 . Only 20% of fish were able to ascend a 2·7 m section with a mean velocity of 122 cm s-1 . Rhinichthys cataractae actively selected low-velocity pathways located along the bottom and corners of the flume at all test velocities and adopted position-holding behaviour at higher water velocities. Mean volitional sprint speed was 174 cm s-1 when fish volitionally sprinted in areas of high water velocities. Swimming performance generally increased with water temperature and fish length. Based on these results, fishways with mean velocities <64 cm s-1 should allow passage of most R. cataractae. Water velocities >100 cm s-1 within structures should be limited to short distance (<1 m) and structures with velocities ≥158 cm s-1 would probably represent movement barriers. Study results highlighted the advantages of evaluating a multitude of swimming performance metrics in an open-channel flume, which can simulate the hydraulic features of fishways and allow for behavioural observations that can facilitate the design of effective passage structures.

Sprint Swimming Performance of Shovelnose Sturgeon in an Open-Channel Flume

Abstract The sprint swimming performance (Vmax) of twenty-five adult wild shovelnose sturgeon (Scaphirhynchus platorynchus) was studied in an outdoor experimental flume at four conditions consisting of two temperatures (12 °C and 19 °C) and two flows (High and Low). The fastest maximum velocity (Vmax) achieved in an individual trial was 3.73 m s-1, which is the greatest sprint velocity ever reported for a sturgeon species. The mean (SD) Vmax by trial was 2.94 (0.56) m s-1 for the Low Velocity 12 °C trial, 2.13 (0.50) m s-1 for the Low Velocity 19 °C trial, 3.01 (0.47) m s-1 for the High Velocity 12 °C trial, and 3.21 (0.88) m s-1 for the High Velocity 19 °C trial. We did not detect a statistically significant difference in swim speeds among the trials. Individual shovelnose sturgeon performed maximum sprint speeds ranging from 1.29 to 3.73 m s-1. Shovelnose sturgeon were able to reach maximum velocities for only a fraction of a second before returning to slower velocities, and often recorded multiple peaks in velocity throughout the course of a swim. The sprint velocities from our laboratory study indicate that the swimming capability of shovelnose sturgeon and possibly other sturgeon species is underestimated. The results of this study provide data that might support design and analysis of fish passage projects for shovelnose sturgeon and other sturgeon species.

Swimming Capabilities of Arctic Grayling

Abstract A native population of arctic grayling (Thymallus arcticus) exists in the upper Missouri River drainage of Montana. While formerly abundant, agricultural practices, predation, angling pressure, barriers to mobility, and competition from other species appear to be the causes of decreased presence of artic grayling in the Northwest (Skaar 1989). The purpose of this study was to augment the information base of the swimming ability of arctic grayling and to examine the effect of repeated trials using the same fish. Forty hatchery-raised grayling were separated into two cohorts and reared in an artificial stream. The mean fork length of all fish was 290 mm (SD ± 16). Cohort 1 was tested in a swim chamber experiment once per week for three consecutive weeks. Cohort 2 was tested only once in the swim chamber sixteen weeks later. Each fish was tested by placing it in the chamber initially operating at a low water velocity (30.5 cm s-1) and then regularly increasing the velocity until the fish rested on the screen at the downstream end of the chamber. The maximum water velocity against which each fish held its position was observed, and is reported as the sprint speed (Usprint). Overall the mean Usprint observed was 5.64 BL (body length) s-1 (SD ± 0.78) equal to an absolute velocity of 1.66 m s-1 (SD ± 0.19). Cohort 1 had a mean Usprint of 5.40 BL s-1 (1.62 m s-1) and Cohort 2 had a mean Usprint of 6.33 BL s-1 (1.77 m s-1). There were significant differences, and a generally increasing trend, in Usprint between the successive trials using Cohort 1.