Fin rays and spines are becoming more popular for age and growth analysis. A protocol for processing structures is first to mount the structure in epoxy, then to use a low-speed saw or handsaw to section the structure, and finally to estimate age from the resulting section. Unfortunately, scientists are often unaware of efficient techniques for mounting structures for such analyses. We describe a simple technique for mounting fin rays and spines in epoxy in preparation for sectioning. The advantages of this method include minimal preparation time, low cost, and little or no damage to hard structures. We have used this technique extensively to estimate age from the fin rays and spines of shovelnose sturgeon Scaphirhynchus platorynchus, catostomids, cyprinids, and ictalurids; however, this technique is useful for any species for which fin rays or spines are used in age and growth analyses. In addition, the technique is not limited to fin rays and spines; it can also be used to prepare a variety of other structures, such as scutes, otoliths, and brachiostegal rays.

The population of pallid sturgeon Scaphirhynchus albus in the lower Missouri River between Gavins Point Dam (river kilometer [rkm] 1,305.2) and the confluence with the Mississippi River (rkm 0.0) remains imperiled, little to no natural recruitment occurring. Artificial propagation and subsequent population augmentation (i.e., stocking) may be the only viable option for maintaining pallid sturgeon populations in the lower Missouri River in the near term. Because relatively little is known about the ability of hatchery-reared pallid sturgeon to survive, the objective of this study was to quantify survival estimates for hatchery-reared pallid sturgeon stocked into the lower Missouri River. We used stock-recapture data collected from 1994 to 2008 to derive survival estimates based on the Cormack-Jolly-Seber model within program MARK. Since 1994, a total of 78,244 hatchery-reared pallid sturgeon have been released and 1% of these have been recaptured. Recapture numbers by size at stocking were as follows: 48 age 0, 730 age 1, and 38 older than age 1. Stocked age-0 hatchery-reared pallid sturgeon had an estimated apparent survival rate of 0.051 (SE ¼ 0.008), compared with 0.686 (SE ¼ 0.117) for age-1 fish and 0.922 (SE ¼ 0.015) for fish older than age 1. Our analysis confirms that hatchery-reared pallid sturgeon can survive in the wild and contribute to the overall population of this species. These estimates should provide critical information for decisions regarding stocking strategies within the lower Missouri River and enable biologists to estimate the number of stocked pallid sturgeon that reach sexual maturity.[Article] FIGURE 1.-Map of the lower Missouri River from Gavins Point Dam at Yankton, South Dakota (rkm 1,305.2), to the confluence with the Mississippi River at St. Louis, Missouri (rkm 0.0). Stars indicate pallid sturgeon stocking locations. 672 STEFFENSEN ET AL.FIGURE 3.-Estimated annual apparent survival rates of hatchery-reared pallid sturgeon in the Missouri River during 1992-2007 for three age-classes. The errors bars represent 95% confidence intervals. 676 STEFFENSEN ET AL.

Shovelnose sturgeon Scaphirhynchus platorynchus have become an increasingly important commercial species in the upper Mississippi River (UMR) due to collapsing foreign sturgeon populations and bans on imported caviar. In response to concerns about the sustainability of the shovelnose sturgeon fishery in the UMR, we began this study to describe shovelnose sturgeon population demographics and evaluate the influence of commercial harvest on shovelnose sturgeon populations in the UMR. A total of 1,682 shovelnose sturgeon were collected from eight study pools of the UMR in 2006 and 2007 (i.e., Pools 4, 7, 9, 11, 13, 14, 16 and 18). Shovelnose sturgeon from upstream pools generally had greater lengths, weights, and ages than shovelnose sturgeon from downstream pools. Additionally, mortality estimates were also lower in upstream pools (i.e., Pools 4, 7, 9, and 11) compared to downstream pools (i.e., Pools 13, 14, 16, and 18). Analyses indicated that decreased growth of shovelnose sturgeon may be a consequence of commercial harvest in the UMR. Modeling of potential management scenarios suggest a 27-inch minimum length limit is necessary to prevent growth and recruitment overfishing of shovelnose sturgeon in the UMR.

We evaluated the precision of samples and the number of stock‐length fish collected by means of standard methods used for sampling North American freshwater fishes from 2010 to 2013 in Kansas. Additionally, we used resampling procedures to determine the number of gear deployments needed to achieve a relative standard error (RSE) of 25% for the CPUE and collect 100 stock‐length individuals. Median RSE of electrofishing samples was generally less than 25% for Largemouth Bass Micropterus salmoides in all sizes of reservoirs and for Channel Catfish Ictalurus punctatus in medium (251–1,000 acres) and large reservoirs (greater than 1,000 acres). The RSE estimates were generally >25% for Bluegill Lepomis macrochirus and crappies Pomoxis spp. collected in trap nets and palmetto bass (female Striped Bass Morone saxatilis × male White Bass M. chrysops) and Walleye Sander vitreus sampled in gill nets. With few exceptions, 100 stock‐length individuals of all target species (e.g., Largemouth Bass, Bluegill, crappies, palmetto bass, Channel Catfish, Walleye) were not sampled at current levels of effort. Resampling procedures indicated that fewer than 20 deployments were usually needed to obtain an RSE ≤ 25% and 100 stock‐length fish for Largemouth Bass in smaller impoundments (i.e., <250 acres); however, more than 20 deployments were needed in larger impoundments. The median effort needed to achieve an RSE ≤ 25% for Bluegills and crappies in trap nets varied and may exceed what some biologists find practical. Fewer gill‐net deployments were needed to reach an RSE ≤ 25% for palmetto bass and Walleyes than to collect 100 stock‐length fish. Our results indicate that more samples than are currently prescribed are generally needed to precisely sample sport fishes by means of standardized protocols in Kansas reservoirs. In some instances, obtaining precise samples may not be logistically feasible. In these situations, biologists should be aware of the potential shortcomings of sampling protocols and set objectives accordingly. Received May 12, 2014; accepted August 23, 2014

Fin rays are a common structure used in age and growth analyses, but many inconsistencies exist regarding removal and processing methodology. The purpose of this study was to evaluate precision of age estimates obtained from shovelnose sturgeon, Scaphirhynchus platorynchus (Rafinesque) fin rays sectioned at different locations. Fin rays were examined from 203 shovelnose sturgeon sampled from Pools 9, 13 and 14 of the Mississippi River. Three readers provided age estimates for sections acquired from five locations along fin rays to determine the optimum location for removing and sectioning fin rays. Precision and readability were generally greater for fin ray sections close to the articulating process on the fin ray (i.e. proximal) and decreased as sections approached the tip (i.e. distal). Based on these results, it is recommended that scientists remove shovelnose sturgeon fin rays at the articulating process and section immediately distal to the conspicuous curve in the fin ray close to the articulating process of the ray. K E Y W O R D S :ageing, fin ray, shovelnose sturgeon.