孵化季节对阿根廷滑柔鱼生长发育的影响

头足类属种具有寿命短、终生一次繁殖产卵的生长发育特性,这些特性往往与仔鱼的孵化季节密切相关且影响世代的繁衍交替。为此,基于日龄判读和孵化月份推算,研究阿根廷滑柔鱼性腺成熟个体大小与孵化月份的效应关系,分析孵化月份对其生长发育的影响。结果显示,阿根廷滑柔鱼性腺成熟雌性个体的胴长为(246.59±40.36) mm,日龄为(293.79±32.68) d,平均生长速率为(0.84±0.11) mm/d;成熟雄性个体的胴长为(222.82±28.60) mm,日龄为(299.24±32.97) d,平均生长速率为(0.75±0.08) mm/d。性腺成熟个体的孵化月份为3—8月。随着孵化月份推移,性腺成熟个体的日龄显著降低,而平均生长速率逐渐增加;性腺成熟个体胴长大小与其平均生长速率密切相关;孵化月份对雌雄个体生长发育的影响效应具有一致性,较早孵化的个体生长速率较慢,而晚孵化的个体生长速率较快。研究表明,阿根廷滑柔鱼的生长发育与孵化季节密切相关,不同孵化月份的个体通过调节生长速率以达到性腺成熟胴长。

Effects of hatching season on the growth and development in Illex argentinus

Cephalopods are characterized by their short lifespan and semelparous strategy, while in which the growth and development are highly correlated with the hatching seasons that highly influence the alternation of generations. Herein, based on statolith daily growth zones and back calculation of the hatching months, the size attainment of sexual mature Illex argentinus, an important world fishery squid species, was investigated and its relation to hatching months was analyzed using statistical methods. The results showed that mature females were measured an average mantle length (ML) of (246.59?40.36) mm, an average daily age of (293.79?32.68) days, and a life history average growth rate of (0.84?0.11) mm/d. For mature males, the animals were measured (222.82?28.60) mm ML, (299.24?32.97) days of average daily age and (0.75?0.08) mm/d of life history average growth rate. Both females and males were estimated hatching months from March to August. As the hatching months progressed, both mature female and male I. argentinus showed a significant decrease in daily age, while they had a higher life history average growth rate. There was a significant relationship between maturity size attainment and life history average growth rate. The effects of hatching months on the attainment of maturity size was highly consistent for both female and male I. argentinus, in which the earlier hatched individuals showed slower growth rate, while the later hatched ones grew faster to catch up the maturity size, possibly in order to cope with the coming spawning season. These evidences indicate the growth and development in I. argentinus are significantly related to hatching seasons, and individuals of different hatching months reach their sexual maturity size by adjusting their growth rate, in which later-hatched individual likely appears to grow faster than earlier-hatched ones.