Hatch timing of largemouth bass: implications for recruitment at the Northern edge of their native range
Creators: name: Coppola, Giancarlo
name: Kelling, Craig J.
name: Dembkowski, Daniel J.
name: Isermann, Daniel A.
Publisher: name: Taylor & Francis
Year: 2024
Subjects: subject: Physiology
subject: FOS: Biological sciences
subject: Environmental Sciences not elsewhere classified
subject: Ecology
subject: Sociology
subject: FOS: Sociology
subject: Biological Sciences not elsewhere classified
subject: Inorganic Chemistry
subject: FOS: Chemical sciences

description: Climate-related shifts in hatch timing could mean that age-0 largemouth bass <i>Micropterus salmoides</i> in north temperate lakes reach larger sizes and experience higher survival, which may contribute to increased prevalence of this species in many lakes. However, information on age-0 largemouth bass life history is lacking for these lakes. We estimated hatch dates, daily growth rates (DGR), and length-based probability of piscivory of age-0 largemouth bass in Wisconsin lakes to: (1) provide baseline data on early life history; (2) compare hatch timing between years with different spring temperature regimes, and (3) project how shifts in hatch timing might influence total length (TL) distributions of age-0 bass if mean DGR remained constant. Most age-0 largemouth bass (&gt;90%) collected from ten Wisconsin lakes (<i>N</i> = 746) hatched between 23 May and 24 June during 2012 and 2013 and did not switch to piscivory during their first summer. Prevalence of positive correlations (16 of 24 lake-year pairings) between TL in and age indicates hatch timing may influence TLs attained by age-0 largemouth bass in August in some lake-years. Mean daily water temperatures in May 2012 were 3.1 °C warmer than in May 2013 for the five of the six lakes where hatch dates were estimated in both years. On average, earliest and median hatch dates for age-0 largemouth bass in these six lakes were 10–11 d earlier in 2012 than in 2013 and hatch duration was approximately 8 d longer in 2012. Despite differences in hatch timing, mean DGR was relatively consistent (range = 0.61–0.74 mm/d) between lakes and years. Simple simulations suggest that earlier hatch dates could result in more age-0 largemouth bass reaching TLs associated with piscivory and overwinter survival by the end of their first summer if growth rates did not change, which could translate to higher recruitment. Most age-0 largemouth bass (&gt;90%) collected from ten Wisconsin lakes (N = 746) hatched between 23 May and 24 June during 2012 and 2013 and did not switch to piscivory during their first summer.Warmer daily water temperatures in May 2012 (3.1 °C warmer than in May 2013) were associated with earlier median hatch dates (10 d earlier) and longer hatching durations (8 d longer) for age-0 largemouth bass in six lakes where hatch dates were estimated in both years, but mean daily growth rate did not differ between years.Simple simulations suggest that earlier hatching may result in more age-0 largemouth bass reaching total lengths associated with piscivory and overwinter survival at current growth rates, which could translate to higher recruitment. Most age-0 largemouth bass (&gt;90%) collected from ten Wisconsin lakes (N = 746) hatched between 23 May and 24 June during 2012 and 2013 and did not switch to piscivory during their first summer. Warmer daily water temperatures in May 2012 (3.1 °C warmer than in May 2013) were associated with earlier median hatch dates (10 d earlier) and longer hatching durations (8 d longer) for age-0 largemouth bass in six lakes where hatch dates were estimated in both years, but mean daily growth rate did not differ between years. Simple simulations suggest that earlier hatching may result in more age-0 largemouth bass reaching total lengths associated with piscivory and overwinter survival at current growth rates, which could translate to higher recruitment.