Reproductive potential of the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) (Decapoda: Palinuridae) male: Implications for broodstock management techniques

Abstract

We investigated the effects of body size on the reproductive potential of the males of the Japanese spiny lobster Panulirus japonicus (von Siebold, 1824) under laboratory conditions to develop broodstock management techniques. The males were divided into three groups based on body size, each with three individuals: large (~90 mm carapace length (CL)), medium (~70 mm CL), and small (~60 mm CL). To evaluate the male reproductive potential, male lobsters were individually stocked in compartments in the tanks, and ten females with similar body size (~54-60 mm CL) were assigned to each male. Oviposition, egg fertilization rate, and clutch size were examined for females. Male body size affected the rates of oviposition and egg fertilization of the partners, resulting in lower reproductive success in the small-size male group. Female body size was associated with the clutch size, whereas male body size did not affect it. The egg fertilization rate, which was mediated by the male reproductive trait, affected the clutch size; low fertility reduced the clutch size. Our mating experiments highlighted the size-dependent reproductive potential of P. japonicus males, and we recommend that small males should not be used as broodstock in larviculture of this lobster.