The clam: its shell is slightly triangular, with a rounded ventral edge, a thick shell, and two shells of equal size. (As shown)

Life habits:

The clam has the habit of moving from the mid-tide area to the lower-tide area with the change of water quality factors or growth habit, commonly known as "running current". That is, in the process of growth in addition to its axe feet to move, but also through the secretion of gelatinous bands and move with the tide. Move the season, mainly in late May to late June and mid-September to the end of the two phases of the high tide period of the early tide and ebb tide, especially in May-June the most prevalent. When the tide stops, the movement is terminated, the clams dive into the beach and the transparent band disappears.

The clam is dioecious, no sex change phenomenon, generally two years of sexual maturity, sex ratio of 1:1, mature gonads surrounded by viscera block and extend to the base of the foot in the breeding season with the naked eye observation of the gonads can be distinguished from male and female, male gonads milky white, female gonads yellowish. Both sexes have no secondary sexual characteristics in appearance. Eggs are sedimentary, round and spherical, 72-90 μm in diameter, with a gelatinous membrane outside the primary oocyte membrane, called the secondary oocyte membrane. The head of the spermatozoon is slightly concave on one side, narrowly cocoon shaped, and about 3 μm long. Before the gonads are immature in April and when the gonads recede after the breeding season in October, it is difficult to distinguish between male and female clams, and more than 90% of the clams do not have any visible eggs or spermatozoa in the dissected gonads. The amount of eggs carried and spawned by clams is closely related to the size of individuals and external conditions. According to anatomical determination, the amount of eggs carried by clams of 3 or 4 years of age is 40-2 million, and the amount of eggs discharged is 20-40 million. Mature clams reproduce once a year, but the reproductive cells of clams are matured in batches, discharged in batches, fertilized and incubated in seawater, metamorphosis and growth.

Nationally, clams reproduce from March to September, but changes in sea conditions and climate factors can affect the advancement or postponement of the clam breeding season. Generally speaking, the south is earlier than the north, the breeding period of clams in the country: Guangxi May-July, Fujian, Jiangsu June-July, Liaoning, Shandong July-August (Qingdao May-September). Clam breeding water temperature 24-25.5 ℃, the best water temperature 25 ℃.

Reference:

/link?url=BL9mDDQZCduO0a3JrgofmN3LD06pwyNPmJhSalDUQa_60FnsWAde1rP8ZxrrFvkxn- Ik7cgBhI1ECWH6x4NOnq