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Shoals of hatchery-reared and wild sea bass juveniles Dicentrarchus labrax were tested for differences in their antipredator responses towards a potential live predator, the eel Anguilla anguilla. Eight experimental shoals (i.e. replicates), each composed of 15 individuals from the same stock of juveniles (i.e. wild or hatchery), were video recorded for 5 min before and after predator exposure. A set of behavioural variables were measured during the pre-stimulus and stimulus phases of each test and compared between the two groups of replicates. Results showed that in both hatcheryreared and wild juveniles predator exposure elicited a significant increase in the mean level of shoal cohesiveness and mean shoal distance from the predator, and a significant decrease in the mean shoal distance from the bottom. Shoals of wild juveniles, however, aggregated more quickly and reached higher shoal cohesiveness within the first 20 s of the stimulus period than shoals of hatchery-reared fish. During this period, the wild fish also reached the highest peak in shoal cohesiveness, which then decreased gradually towards the levels observed before predator exposure. Another component of the antipredator response, the predator inspection behaviour, was fully developed in both wild and hatchery fish. Wild fish, however, tended to inspect the predator at a closer distance than hatchery fish. # 2004 The Fisheries Society of the British Isles

In this paper the breeding sound production among gobiids is reviewed. Results of recent comparative studies on both pre-spawning (courtship) and spawning sound production in the three italian freshwater gobiids are reported. A significant production of sounds associated to mating was discovered in two of these species. Furthermore, the quantification of acoustic behaviour across the spawning period (i.e., from the beginning of oviposition until the departure of the female from the male's nest) revealed a pattern of spawning sound production similar in the two species.

Attacks by resident lactating female mice were examined in a variety of situations. Relatively few attack bites to vulnerable body regions were seen when pairs of unfamiliar lactating females fought, establishing social status prior to communal nesting. Sexually naive male and female intruders were equally prone to attack by lactating females, but patterns of bite attack generated by them were very different; males received the more damaging attacks. More signs of "fear" were seen in the lactating females' responses to male rather than female intruders. Varied motivations may underlie attacks by lactating females directed to conspecific intruders. Defensive patterns of biting by lactating females are more consistently directed towards males, intruders that are more likely to harm or destroy the litter. Although attacks by females rarely thwarted infanticide by male intruders, the behavior may acutely protect parental investment.