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

Abstract

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 individuallevel 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 release) across a latitudinal gradient encompassing virtually the entire south-north range of smallmouth bass (i.e., southern Missouri [MO], southern Ontario [SON], and northern Ontario [NON]) and compared these treatment groups with nonangled controls. We also quantified the extent to which physiological disturbance associated with angling varied across latitudes (peripheral populations [MO and NON] versus the intermediate-latitude population [SON]). Whole-blood lactate and glucose levels were highest in fish subjected to ST conditions, indicating increased stress; this pattern was conserved across all latitudes (although there was some evidence of intraspecific variation in stress response). Additionally, the pattern of brood abandonment was similar among fish at all three latitudes; ST fish exhibited the highest rates of nest abandonment (MO: control ¼ 9.1%, CR ¼ 0%, AE ¼ 9.1%, ST ¼ 100%; SON: control ¼ 10%, CR ¼ 10%, AE ¼ 10%, ST ¼ 50%; NON: control ¼ 7.7%, CR ¼ 0%, AE ¼ 9.1%, ST ¼ 50%). Interestingly, fish from the most southerly latitude, where regulations are the most liberal, abandoned nests at higher rates than did fish from the other latitudes. Collectively, these data reveal that the reproductive success of individual smallmouth bass can suffer from interaction with anglers, particularly in a tournament context, regardless of the region. Further study is needed to determine the extent to which individual nest success is relevant to recruitment and how this relationship varies across latitudes.

Effects of Tournament Compared with Catch and Release Angling on Nest Abandonment of Largemouth Bass

“…Catch-and-release fish were removed from the nest for a much shorter duration than tournament fish and did not experience the increased stress of weigh-in and displacement from nesting location. The abandonment rate of catch-and-release fish in our study (32%) was higher than that observed in similar studies with largemouth bass (about 10%; Siepker et al 2009) and smallmouth bass (0-10%; Suski et al 2003b;Hanson et al 2008;Siepker et al 2009). However, Philipp et al (1997) reported abandonment rates of 44% for catch-and-release smallmouth bass and largemouth bass, which were greater than rates for our study fish, albeit fish in both studies were removed from nests for similar periods.…”

“…Climate, nest predators, condition of fish, and angling pressure can vary with latitude and may influence abandonment rates. Smallmouth bass exposed to tournament conditions in Missouri (similar latitudes to this study) had higher abandonment rates than two populations in Ontario (Hanson et al 2008). Similarly, catch-and-release angling abandonment rates of largemouth bass in our study (34%) were higher than rates for four lakes in Ontario (10%; Siepker et al 2009).…”

“…However, the weigh-in process has not been considered for largemouth bass and has been identified as one of the most significant stressors for tournament angled fish resulting in significant metabolic disturbances and reduced physiological condition . Smallmouth bass experience higher abandonment rates than largemouth bass when subjected to tournament angling that includes a weigh-in (Hanson et al 2008). Hanson et al (2007) found a higher abandonment rate among largemouth bass subjected to weigh-in procedures during which time their broods were manually reduced by 90% than did individuals not experiencing the weigh-in or brood reductions.…”

“…In one study, Hanson et al (2008) noted a difference in nest-abandonment rates when simulated tournament procedures were applied to smallmouth bass across varying latitudes, suggesting that latitudinal variation in nest-abandonment may exist. Therefore, to better understand the effects of tournament angling on black bass, nest abandonment needs to be evaluated for largemouth bass in middle latitudes.…”

Intraguild predation between spawning smallmouth bass (Micropterus dolomieu) and nest‐raiding crayfish (Orconectes rusticus): implications for bass nesting success

“…This approach allowed for a lakewide estimate of nest abandonment, as well as examination of variation in abandonment rate among transects given the spatial heterogeneity of crayfish. We began marking and tracking nests at the onset of spawning (when water temperature reached 15°C; Hanson et al, 2008). Initiation of spawning was highly synchronous, with a vast majority of nests beginning within the same 3-day period (19-21 May 2010).…”