Abstract

The status of social dominance may have consequences for the well-being of cichlids. These fish show territorial and aggressive behavior and are important for behavioral studies. The aim of the present study was to evaluate sperm variables of motility, growth performance and reproductive performance according to the social status of African cichlid Aulonocara nyassae. The experiment was divided into: Phase 1 - establishment of social statuses between males, 40 males of A. nyassae were kept in four tanks (42 L useful volume) with 10 animals in each tank for 30 days. During this period, the animals were classified according to social status as dominant, subdominant and submissive fish; Phase 2 ? reproduction, one male of each social status (dominant, subdominant and submissive) per tank was selected, for a total of four males for each status and a total of 12 males. One male of each social status of each of original four tanks (total 12 males) was placed in a new tank with three females, for a total of 12 new tanks, and; Phase 3 - individualization of males (removal of females), the males were separated from their females and placed individually in 12 tanks. In Phase 1, only one dominant male was detected in a group of 10 animals, between 6 and 7 subdominant animals and, 2 and 3 submissive animals. The final weight (FW) was higher for dominant fish. The sperm concentration, motility rate (MOT), Amplitude of lateral head movement (ALH), linearity (LIN), straightness (STR), wobble (WOB) and beat-cross frequency (BCF) did not show statistical difference between dominant and subdominant fish. Curvilinear velocity (VCL), Straight-line velocity (VSL) and Average path velocity (VAP) were higher for subdominant fish. Motility time was higher for the dominant male. In phase 2, the male performance was higher for dominant and subdominant than submissive males. MOT and VAP were higher for dominant males. ALH, LIN, STR, WOB and BCF were higher for subdominant males. The social status of the males did not influence the growth and reproductive variables of the females. In phase 3, the male performance was higher for dominant and subdominant fish. MOT, VCL, VSL, VAP and WOB were superior to dominant and subdominant males. LIN and STR were superior for subdominant males. BCF was superior to dominant. Therefore, sperm quality and growth performance were influenced by changes in the social statuses.