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 88C to 308C for 87 d to determine the effect of temperature on growth, condition, feed efficiency, and survival. Growth occurred at temperatures from 128C to 308C; the optimal temperature predicted by regression analysis was 22.48C, and the minimum temperature needed for growth was greater than 10.08C. The maximum feed efficiency predicted by regression analysis was 24.5% at 21.78C, and condition factor was highest in the 188C treatment. Mortality was significantly higher at 288C and 308C than at lower temperatures but less than 10% across the thermal regimes tested and 0% at 14-188C. Mortality was observed at and below 128C, suggesting that extended periods of low temperature may deplete energy reserves and lead to higher mortality. Rearing juvenile shovelnose sturgeon at temperatures above 248C reduced the growth rate and feed efficiency and increased mortality. Temperatures in the range 18-208C appeared to maximize the combination of condition, growth, and feed efficiency while not increasing thermal stress. This study corroborates field studies suggesting that altered temperature regimes in the upper Missouri River reduce the growth of shovelnose sturgeon. This information may help protect the thermal habitat critical to the species and guide restoration efforts by delineating temperature regime standards for regulated rivers and those affected by hydroelectric facilities and suggesting new criteria for conservation propagation.

The generally accepted 2% ratio of transmitter weight to body weight constrains or precludes telemetry studies examining the timing and location of spawning of small adult westslope cutthroat trout Oncorhynchus clarkii lewisi in headwater streams. We empirically determined effects of surgically implanted dummy transmitters ranging in weight from 1 to 5 g on the swimming stamina and growth of small (81.3–206.9 g) adult westslope cutthroat trout in the laboratory to establish acceptable transmitter weights for field studies on this species. Mean growth rates and swimming stamina were not significantly different among treatments, including controls. No precipitous decline or threshold beyond which performance deteriorated markedly was observed. Data collected using telemetered westslope cutthroat trout implanted with transmitters less than about 4% of body weight should therefore approximate information about untelemetered individuals without significant bias. However, we also detected subtle effects on growth within this transmitter weight range related to individual transmitter–body weight ratios (0.5–5.3% initially), and there were indications that swimming stamina was affected similarly. Each 1% increase in transmitter– body weight ratio elicited an 11.6% decrease in growth and a possible 5.6% decrease in swimming stamina at 6 weeks postimplantation. Therefore, transmitter selection should weigh the costs of increased transmitter weight on fish performance against the benefits of longer transmission durations. In the case in which transmitter weights approaching 4% of body weight are necessary to complete a study and slight decreases in performance are not expected to affect findings materially, such weights may be acceptable. In other cases, researchers should choose the lightest possible transmitters that allow study goals to be achieved and not automatically select transmitters weighing 4% of body weight.

Determining the optimal rearing temperature for the June sucker Chasmistes liorus has been identified as a key component necessary for the design of a new June sucker hatchery and for achieving the June Sucker Recovery Implementation Program supplementation goal of 350,000 fish of 20‐cm length annually. A laboratory study was conducted to monitor the performance of June suckers reared at average temperatures of 8.3, 10.1, 12.3, 14.0, 16.1, 18.5, 20.5, 21.8, 23.9, 25.9, 27.9, and 29.7°C for 16 weeks. In this study, quadratic regression analysis was used to determine maximum condition factor and weight gain, respectively, and 22.5°C and 21.9°C were identified as the maximum water temperatures. According to this same regression analysis, the maximum feed efficiency and total length increase occurred at 21.6°C and 23.7°C, respectively, during the 16‐week study. The modified acclimated chronic exposure water temperature (50% survival for 60 d) was greater than 27.9°C. Spinal and fin deformities increased during this study in all treatments, and these malformations appear to be diet related. There was no temperature effect on deformities, but temperature did affect overall survival.

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Reports from hatcheries have demonstrated that commercially available diets are inadequate for June Suckers Chasmistes liorus and suggest that fish quality can be improved through species‐specific diet optimization. To determine dietary protein and lipid levels for juvenile June Suckers, practical‐type diets were formulated with 35, 40, or 45% protein and 8, 12, or 16% lipid and tested in a 3 × 3 factorial design. Two additional diets (45% protein and 16% lipid [45:16] without dicalcium phosphate supplementation and 45:16 with 2× dicalcium phosphate) were formulated to test the necessity of dicalcium phosphate supplementation. Each diet was fed to three replicate tanks (average initial fish weight ± SD = 4.48 ± 0.24 g) of fish per treatment (85 fish/tank); only duplicate tanks were used for the nondicalcium phosphate‐supplemented treatment. Fish were reared in 80‐L tanks supplied with 4 L/min of 22°C spring water and fed 6–4% body weight (BW)/d by automated belt feeders, 6 d/week. At the end of 12 weeks of culture, tissue samples were obtained to determine nutrient partitioning. An acute temperature challenge was also conducted to investigate dietary adequacy. Significant effects of diet on growth and temperature tolerance were observed. Fish fed the diet with 45% crude protein gained more weight than did fish fed 40% or 35% crude protein, and fish fed 16% dietary lipid gained more weight than did fish fed 12% and 8% crude lipid. However, the composition of this growth indicated that fish fed the 16% lipid stored larger amounts of lipid in both the visceral cavity and the muscle. A significant negative interactive effect of dietary protein and lipid on temperature tolerance was observed at 45% crude protein and 16% lipid. Results of this study define acceptable ranges of dietary protein and lipid for juvenile June Suckers and provide culturists information to make better choices regarding appropriate diets for this species.

Ostrich ISSN: 0030-6525 (Print) 1727-947X (Online) Journal homepage: http://www.tandfonline.com/loi/tost20 INTRODUCTION Observations detailed in this paper were made in the vicinity of Txatxanika camp on the Khwae River, Moremi Wildlife Reserve, Botswana. On a small island of about three acres in extent, approximately 60 nests of Purple Heron Ardeapurpurea, six nests of Wood Stork Zbis ibis, and eight nests of Marabou Leptopfilos crumeniferus were found. The island was densely covered in Ficus verrucolosa trees. The nests of the two storks were in the upper stratum of the trees while those of the heron were situated in the middle stratum from 1.5 to 4.5 m above the ground which was in parts flooded. The vegetation consisting solely of F. verrucolosa was very thick and the middle Stratum consisted of entangled and intertwining branches of the trees.

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Five commercial diets and two formulated feeds were fed to initial‐feeding Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri fry and Snake River cutthroat trout O. clarkii spp. (currently being petitioned for classification as O. clarkii behnkei) fry for 18 weeks from June 16 to October 18, 2006, to evaluate fish performance. Eyed eggs from Yellowstone and Snake River cutthroat trout were received from the Yellowstone River State Fish Hatchery and Jackson National Fish Hatchery, respectively. Each diet was fed to four tanks of each subspecies of cutthroat trout (7 diets × 4 tanks/diet × 2 cutthroat trout subspecies = 56 tanks). Skretting Nutra‐Plus provided optimal fish weight, total length, survival, and feed conversion for Yellowstone cutthroat trout. The weight and total length of Snake River cutthroat trout were also greatest when fish were fed Skretting Nutra‐Plus. Skretting Nutra‐Plus is no longer available, but Skretting/Bio‐Oregon Bio‐Vita is very similar; this feed and similar premium feeds from other manufacturers should be considered for future cutthroat trout propagation programs.