Observations on the reproductive and larval biology ofBlennius pavo (Pisces: Teleostei)

Social behaviour and spawning of adultBlennius pavo kept in the laboratory are described. Eggs are deposited in batches on the walls of artificial spawning places (PVC pipes). One male guards and tends the eggs of different females in one spawning place. Larval hatching occurs in groups according to oviposition. Minimum incubation temperature is around 14–15°C. Larval survival in 1-1 rearing jars is not related to larval total length but to density of larval stock. An experimental population of laboratory reared juvenile and adolescentB. pavo displays a male to female ratio of 1:1.4. Factors possibly influencing the sex ratio of this littoral fish are discussed in view of the situation in its natural environment.