Michael J. Siepker

Influence of Circle Hook Size on Hooking Efficiency, Injury, and Size Selectivity of Bluegill with Comments on Circle Hook Conservation Benefits in Recreational Fisheries

Abstract Hook size is an important consideration in the use of circle hooks as a conservation tool for minimizing the injury and mortality of marine fishes, but little is known about the role of hook size in the performance of hooks in recreational freshwater fisheries. In this study, we angled 100 bluegills Lepomis macrochirus on each of five different-sized circle hooks (1/0, 2, 6, 10, and 14). The largest hook size (1/0) had low hooking and capture efficiency but selected larger individuals. The smallest hook size also had low hooking efficiency and resulted in the selection of smaller individuals. Intermediate hook sizes captured fish of intermediate size. Jaw hooking rates generally increased with decreasing hook size, whereas roof hooking rates decreased. Gullet hooking was restricted to the three smallest hook sizes. Relative hooking depth and incidences of bleeding were uniformly low for all hook sizes. Similarly, the fish were generally easy to remove from the hook irrespective of hook size. Our ...

Injury rates, hooking efficiency and mortality potential of largemouth bass (Micropterus salmoides) captured on circle hooks and octopus hooks

Abstract We compared the injury rates, hooking efficiency, and mortality potential of circle hooks and the more conventional octopus hooks for largemouth bass (Micropterus salmoides) captured on minnows in central Illinois. Fish captured on circle hooks (N=125) were hooked less deeply, exhibited less bleeding, and were more easily removed from the hook than were those captured on octopus hooks (N=134). The majority of fish captured using both hook types were hooked in the upper lip. Mortality rates were uniformly low for both hook types (circle, 5.1%; octopus, 6.6%). Fish that were identified as potential mortalities were typically hooked deeply in a vital organ or tissue (i.e., heart, gullet, gill arch), exhibited substantial bleeding, and were difficult to remove from the hook. No size-selective trends were noted among hook types, nor were there any differences in total length among mortalities and survivors. Capture efficiency for circle hooks was half that of octopus hooks. Our results suggest that circle hooks do provide some minimal conservation benefits relative to conventional octopus hooks despite having similar mortality rates.

Individual Reproductive Success of Largemouth Bass and Smallmouth Bass Subjected to Different Components of Competitive Angling Events

Abstract The continued popularity of angling for largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu has led to concerns about the effects it may have on fish populations, including the realized fitness of individuals. Although catch-and-release angling and its effects on nest abandonment have been well documented, very little research has examined the effect that competitive angling practices may have on nest abandonment. We subjected nest-guarding male largemouth bass in one lake and smallmouth bass in four lakes to various competitive angling practices (i.e., livewell retention, release after displacement from the nest, and a combination of these practices) and assessed subsequent nest abandonment. We also examined the importance of nest predation on the nest abandonment decisions of male bass by protecting some of the nests from predation after the angling event. Nest abandonment by largemouth bass was affected by angling treatment, the water depth at the nest site, and brood size bu...

Evaluating a Novel Passive Integrated Transponder Tag in Largemouth Bass

Abstract Passive integrated transponder (PIT) tags are used in fisheries evaluations as a means of marking individual fish because they often have high retention rates, can be passively detected, do not affect fish behavior, and typically do not increase the mortality rates of the study fish. One potential limitation of current PIT tag designs is their glass encapsulation, which could be hazardous to humans if inadvertently consumed. In response to these concerns, plastic infusion process (PIP) PIT tags that are fully encapsulated in food-grade polymers have recently been developed. We tested in experimental ponds the retention rates of two PIT tag types (i.e., glass and PIP) implanted into two anatomical locations (i.e., the intraperitoneal cavity and dorsal musculature) in two groups of largemouth bass Micropterus salmoides. Retention of both tag types was excellent, with only one glass tag being expelled during the study. Survival was higher in control fish than in tagged fish; however, tag type and an...

Latitudinal Variation in Physiological and Behavioral Responses of Nest-Guarding Smallmouth Bass to Common Recreational Angling Practices

Abstract Management policies related to catch-and-release (CR) angling of smallmouth bass Micropterus dolomieu vary widely across the geographic distribution of the species. Some jurisdictions, principally in the northern latitudes, prohibit or limit angling efforts that target nesting male smallmouth bass, whereas angling during the nesting period is generally unregulated in southern jurisdictions. Existing studies of individual-level angling impacts on nesting smallmouth bass have primarily been conducted in the north; thus, the extent to which these findings are relevant to other regions is unknown. In the current study, we sought to systematically evaluate the rates of nest abandonment by nesting smallmouth bass subjected to common angling practices (CR treatment: Brief angling and no exposure to air; air exposure [AE] treatment: Exhaustive angling and 3 min of AE) and tournament practices (simulated tournament [ST] treatment: Exhaustive angling, 2 h of live-well retention, and 3 min of AE prior to re...

Capture Efficiencies of Two Hook Types and Associated Injury and Mortality of Juvenile Muskellunge Angled with Live Baitfish

Abstract Strict harvest regulations and a strong catch-and-release ethic among recreational anglers of muskellunge Esox masquinongy have led to interest in developing strategies for reducing injury and mortality of released fish. With many anglers using live baitfish to capture muskellunge, the use of circle hooks may reduce deep hooking and hence mortality. We contrasted the performance of circle hooks and J-style aberdeen hooks when capturing juvenile muskellunge with actively fished live baitfish. The J hooks performed better than circle hooks in terms of capture efficiency. The J hooks were more efficient at hooking muskellunge than were circle hooks, but landing efficiency was similar between the two types. Interestingly, injury was judged to be low regardless of hook type. Neither anatomical hooking location nor hooking depth differed significantly between fish captured on J and circle hooks. No fish were hooked in potentially lethal locations (e.g., gullet or eye) during the use of either hook type...

Evidence of Reduced Reproductive Success of Nesting Largemouth Bass Sampled with Standard Electrofishing Procedures

Abstract Fisheries biologists commonly use electrofishing as a fish collection technique. Because electrofishing is often conducted in the spring, it has the potential to negatively affect the reproductive activities of largemouth bass Micropterus salmoides, particularly the parental care activities of the nest-guarding males. To assess the effect of electrofishing on nest-guarding activities, we electrofished parental males from their nests in an Illinois lake, held them in a tank for 30 min, and released them 0.25 km from their nest sites—as would be done during routine surveys. We then assessed the presence or absence of broods and males on their nests 24 h later to determine rates of abandonment. Electrofished males had greater levels of nest abandonment (41%; N = 34) than did control males (9.5%; N = 42). The developmental stage of the offspring present in the nest during the electrofishing, however, did not influence abandonment rate. These results suggest that springtime electrofishing can negative...

Effects of Four Hook Removal Techniques on Feeding, Growth, and Survival of Deeply Hooked Largemouth Bass

Abstract Largemouth bass Micropterus salmoides were intentionally deeply hooked using a size 2 kahle style live-bait hook and then subjected to one of four hook removal methods: hook left in place, standard removal, standard removal with a barbless hook, and a recently popularized “gill” technique whereby the hook eye is pulled behind the last gill arch and rolled to pop the barb free. Fish hooked in the oral cavity (not deeply hooked) were used as controls. Initial survival and consumption were evaluated for 6 d posthooking in tanks, whereas ponds were utilized to evaluate longer-term (up to 11 months) survival and growth. Food consumption in tanks was significantly higher for orally hooked controls and fish subjected to the gill technique than for those in the other treatments. Initial, 24-h mortality was less than 11% across treatments and was not significantly different among removal methods or orally hooked controls. No differences in growth or survival among deeply hooked fish subjected to the vario...

Exploring the Influence of Stock–Recruitment Relationships and Environmental Variables on Black Bass and Crappie Recruitment Dynamics in Missouri Reservoirs

Abstract Large reservoirs provide important sport fisheries, but managing these fisheries is difficult because of the multiple biological and environmental variables that interact to shape them. Understanding how sport fish recruitment responds to parental stock and environmental influences would improve our management capabilities. We compiled long-term datasets for 15 Missouri reservoirs and used them to examine the influence of parental stock abundance and a suite of environmental variables on the recruitment of Largemouth Bass Micropterus salmoides, Spotted Bass M. punctulatus, White Crappie Pomoxis annularis, and Black Crappie P. nigromaculatus. Comparisons of log-linear, Ricker, and Beverton–Holt stock–recruit models revealed that the log-linear model was the most parsimonious for Largemouth Bass, White Crappie, and Black Crappie, but the Ricker model was best for Spotted Bass. However, stock–recruit models alone explained less than 13% of the variation in Largemouth Bass, Spotted Bass, and White Cr...

Electrofishing Practices Have Limited Effects on Largemouth Bass Feeding Behavior

Abstract Electrofishing is an effective fish capture technique used by many fisheries professionals. Despite the overall effectiveness of the technique, there have been reported negative consequences attributed to its use. We investigated the time to resumption of feeding for adult largemouth bass Micropterus salmoides subjected to electrofishing procedures compared with that for control fish across a range of sizes and water temperatures. Control fish fed immediately, whereas the resumption of feeding was delayed for a short period in electrofished largemouth bass. Time to resumption of feeding was not influenced by temperature but was influenced by largemouth bass size, with larger fish taking longer to resume feeding than smaller conspecifics. Although a single electrofishing event had limited effects on feeding behavior of largemouth bass, fisheries professionals should remain cognizant of other potential negative effects on fishes.