Analysis of Daily Growth Patterns in Young-of-Year Male Dwarf Surfperch (Embiotocidae:Micrometrus minimus) Suggests Alternative Tactics: Breed or Grow after Birth

Abstract

Abstract Discontinuous variation in daily growth patterns suggests that there are alternative life-history tactics among males of a coastal fish species. Male dwarf perch are known to be mature and reproductively active at birth, exhibiting a high level of material and behavioral expenditure on breeding early in life. Males experience a substantial cost of reproduction in reduced early growth and survival relative to females. Through analysis of daily growth increments in otoliths, we showed that young-of-year males from two populations exhibit a polymorphism in daily growth patterns. A distinctive episode of narrow growth increments and slow growth punctuated the summertime growth record of some males, whereas increment widths were more uniform and growth was more rapid in other males. Discriminant function analysis revealed that features of the daily growth record varied discontinuously, falling into two distinct groups. Early-born males were more likely to exhibit the slow growth pattern, and late-born...