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Grant, Joshua D.; Ingram, Steven J.; Bonar, Scott A.
doi: 10.1002/fsh.10964pmid: N/A
We compared three methods of boat driving and pedal operation using 600‐s transects: these were the parallel continuous (PC), parallel intermittent (PI), and arc‐intermittent (AI) methods for surveying warmwater fishes in reservoirs. We tested differences in total time and distance per transect, CPUE (fish/h, fish/m), and length frequencies of captured fish among methods. The PC method took the least amount of time, while the AI method took the least amount of distance to complete a transect. The AI method provided slightly higher CPUE (fish/h, fish/m) for Bluegill Lepomis macrochirus and Yellow Bass Morone mississippiensis and higher CPUE (fish/m) for Common Carp Cyprinus carpio, Green Sunfish L. cyanellus, and Largemouth Bass Micropterus salmoides. Each method caught similar size ranges of fish; however, there were slight differences in proportions of sizes for Gizzard Shad Dorosoma cepedianum, Largemouth Bass, and Bluegill. Overall, the AI method performed slightly better for a few species; however, difference in the methods were minor. Any technique should work well for monitoring reservoir fish populations when fish/h is the effort metric.
Shoup, Daniel E.; Carl, Dray D.
doi: 10.1002/fsh.10969pmid: N/A
Field evaluations of management manipulations are rarely conducted, in part because they are difficult to design and require large sampling effort. However, many commonly used management approaches have <50% success rate, indicating the need for more research. Herein, we provide a case study illustrating how historic standard sampling data from Oklahoma were used to design robust before–after control–impact study designs to evaluate the effectiveness of stocking saugeye Sander vitreus × S. canadensis as a predatory control for stunted White Crappie Pomoxis annularis populations. Comparing six manipulated lakes with six reference lakes (no saugeye stockings), we found that proportional size distribution, proportional size distribution of preferred‐size fish, and mean length at ages 1 and 2 of White Crappie all improved after stockings, but still fell short of statewide median values. Further, similar improvements in these metrics also occurred in reference lakes, suggesting they were likely caused by regional patterns (flood/drought or temperature effects) rather than management intervention. Thus, we conclude saugeye stockings are not likely to routinely improve stunted White Crappie fisheries. We encourage managers who have historic data to use these data to robustly evaluate management interventions (as illustrated in this study), because our field needs additional information regarding when management interventions will be most effective, versus when they may not have the desired outcome. These historic data sets have considerable utility in providing this type of information. Our case study illustrates the importance of replication and reference lakes to avoid erroneous conclusions in such evaluations.
Clemens, Benjamin J.; Matley, Jordan K.; Klinard, Natalie V.; Lennox, Robert J.; Sortland, Lene K.; Cooke, Steven J.
doi: 10.1002/fsh.10963pmid: N/A
Each year, thousands of fishes are tagged with electronic devices to study their biology and inform fisheries management. Such research assumes that the process of capturing, tagging, and then holding fish to allow them to recover before release (i.e., the “tagging process”) does not alter the physiology, behavior, and survival of these fish. However, the fish can experience physiological challenges during the tagging process that may affect their behavior and survival. We have observed that the rationale used to establish protocols for holding durations and conditions of fish before and following surgery has received little attention. Here, we provide a perspective that: (1) provides an overview of the tagging process and its effects on the physiology, behavior, and survival of fish; (2) highlights the diverse holding conditions and durations used by researchers (that are often inadequately described and seem arbitrary); and (3) identifies key research needs. We conclude that decisions of whether, how, and for how long to hold tagged fish before release depend on diverse circumstances that need to be evaluated by researchers. We recommend that researchers explicitly report the details of how, when, where, and why tagged fish are held to facilitate protocols that benefit fish welfare, science, and management.
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