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Fishery Bulletin 105(3) 



may also depredate eggs or developing embryos directly 

 from the pouch (Curtis, 2004). A wounded wild H. whitei 

 male had a hole in his pouch that precluded mating for 

 nearly three reproductive cycles (-60 days, Vincent and 

 Sadler, 1995). The degree to which predation affects 

 reproductive success in H. guttulatus is unknown, but 



reproductive success in other fishes that provide male 

 parental care is strongly affected by interspecific preda- 

 tion (e.g.. Cole and Sadovy. 1995). 



A fourfold difference in estimated spawning fre- 

 quency between the Arcachon Basin (one brood per year) 

 and the Ria Formosa (4.2 broods per year) indicates that 

 realized annual fecundity varies among H. guttu- 

 _ latus populations. Spawning frequencies are posi- 



tively correlated with temperature in many ma- 

 rine fishes (Bone et al., 1995), including darters 

 (Gale and Deutsch, 1985). Variation in spawning 

 frequency among northern anchovy populations 

 was also linked to energetic constraints (4-20 

 spawnings per year, Hunter and Leong, 1981). 

 With an estimated mean spawning frequency of 

 once per year and a shorter reproductive season, 

 H. guttulatus in the Arcachon Basin may be more 

 vulnerable to environmental stochasticity than 

 the Ria Formosa population. Spawning that oc- 

 curs multiple times within a reproductive season 

 confers fitness benefits, particularly for small- 

 bodied fishes inhabiting variable environments. 

 By spawning fewer times in variable environ- 

 ments, the risk of catastrophic losses of eggs and 

 larvae due to temporarily poor environmental 

 conditions are increased (Nikolsky, 1963; McEvoy 

 and McEvoy, 1992). 



Trends in reproductive activity 



Peaks in the reproductive activity of male and 

 female H. guttulatus in the Ria Formosa lagoon 



