真蛸早期发育形态特征及生长规律研究

Morphology, Growth and Development in the Early Life of Octopus vulgaris

关键词:  真蛸  早期发育  形态特征  生长

Key words:  Octopus vulgaris  Early life development  Morphological characteristics  Growth

摘要:

为了探究真蛸(Octopus vulgaris)早期幼体生长发育特征，在室内水泥池育苗条件下，研究了孵化后1~100日龄真蛸的形态变化特征，并对1~49日龄真蛸的全长、腕长、胴长、胴宽、体重及最长腕的吸盘个数进行了测量。结果显示，在盐度为30~32，水温为18.6℃~26.0℃条件下，初孵仔蛸平均全长为(3.05±0.11) mm，大部分初孵仔蛸外卵黄囊在出膜前已吸收完毕，1日龄仔蛸已开口摄食，17日龄稚蛸开始摄食糠虾，35日龄稚蛸开始营底栖生活，60日龄体色由透明发育为乳白色，80日龄体色已与成体相同，100日龄除性腺外，各器官发育成熟，形态特征与成体基本一致。研究表明，真蛸早期(1~49日龄)发育过程中，体重与全长呈立方函数关系，为y=5×10–5x3– 0.0009x2+0.0072x–0.0132；全长与腕长呈立方函数关系，为y=–0.0012x3+0.0492x2+0.0243x+0.2179；全长、体重、腕长、胴长、胴宽分别与日龄呈立方函数关系，为y=–0.0001x3+0.0105x2–0.0122x+3.0562、y=–2×10–7x3+4×10–5x2–0.0004x+0.0034、y=–0.0004x3+0.0247x2–0.1037x+0.8214、y=–0.0004x3+0.0124x2 +0.0749x+1.4757、y=–3×10–5x3+0.0025x2+0.0354x+1.4026。依据营养类型、形态和生物学特征等参数，将真蛸早期发育分为仔蛸期、稚蛸浮游期、稚蛸底栖期和幼蛸期4个时期。

Abstract:

To explore the growth and development patterns during the early life period of Octopus vulgaris, the morphological characteristics of larva, juvenile, and young O. vulgaris under industrialized breeding conditions were observed and recorded. From hatching to 49 days of age, eight larvae were sampled randomly every two days, and total length, arm length, mantle length, mantle width, body weight, and sucker number in the longest arm were measured. In conditions of water salinity of 30~32 and 18.6℃~26.0℃, the average full length of the newly hatched larva was (3.05±0.11) mm; the yolk sac of newly hatched larvae was absorbed by the larvae themselves before hatching or within 9 hours after hatching; the 1-day-old larva just began to feed and the 17-day-old larva could feed on shrimp; at the age of 35 days, the larvae were ready for benthonic living; the body color of 60-day-old larva changed from transparent to milky white; at the age of 80 days, the body color of the larva is the same as that of the adult; the organs of 100-day-old larva were mature except for the gonads, and the morphological characteristics were consistent with those of the adult. The results showed that O. vulgaris larva (1~49 days of age) body weight exhibited a cubic function growth relationship with total length, represented by the equation: y=5×10–5x3–0.0009x2+0.0072x–0.0132; total length exhibited a linear growth relationship with arm length, represented by the equation: y=–0.0012x3+0.0492x2+0.0243x+0.2179; total length, body weight, arm length, mantle length, and mantle width exhibited a cubic function growth relationship with days respectively, with the regression equations: y=–0.0001x3+0.0105x2–0.0122x+3.0562, y=–2×10–7x3+4× 10–5x2–0.0004x+0.0034, y=–0.0004x3+0.0247x2–0.1037x+0.8214, y=–0.0004x3+0.0124x2+0.0749x+1.4757, and y=–3×10–5x3+0.0025x2+0.0354x+1.4026. We divided the early period of O. vulgaris into four developmental stages: Larvae octopus, juvenile paralarvae octopus, juvenile benthonic octopus, and young octopus. Each stage was determined by feeding style (endogenous or exogenous), morphological and biological characteristics, and ratio between arm lengths and mantle length.