Research Paper Volume 16, Issue 18 pp 12443—12472

Figure 4. Single-housed fish have a longer egg-laying period than group-housed fish. (A) Temporal changes in the number of eggs laid by group- and single-housed fish. Six breeding tanks were prepared one week after the fish reached the young adult stage, and the number of embryos was counted once a week. The left vertical axis represents the number of viable embryos. The thick lines represent the average number of embryos in the six experimental tanks; the thin lines represent the number of embryos in each tank. The thick, blue or pink horizontal lines labeled “H” represent a high fecundity period; the medium lines marked “M” represent a medium fecundity period; and the thin lines labeled “L” represent a low fecundity period. The right vertical axis and black dashed line represent the survival rate and the Kaplan–Meier survival curves of all the fish used in this experiment, respectively. (B) Cumulative number of live embryos obtained at high and medium fecundity levels. *, p < 0.05 by t-test. Each point represents an individual tank. (A, B) G: group-housed fish, S: single-housed fish.