Salinity Adaptability of the Sea Cucumber Apostichopus japonicus and Its Differences from Other Sea Cucumbers

How well does the sea cucumber Apostichopus japonicus adapt to salinity? Apostichopus japonicus is a stenohaline organism, and its suitable salinity range is 26‰-34‰. When salinity falls below 20‰, large numbers of individuals die and develop rot. When the water temperature is below 20°C, the higher the water temperature, the stronger the tolerance of Apostichopus japonicus to low salinity.

The differences between wild Apostichopus japonicus and pen-raised sea cucumbers are very obvious:
1. Tube feet: Wild sea cucumbers Apostichopus japonicus generally grow in sea areas at a depth of about 20, and they move about on their tube feet to search for food, so their tube feet are short and thick; pen-raised sea cucumbers, however, do not need to move because they have long been fed bait put out by the farmers, and they live in water areas, so the locomotor role of their tube feet declines, their suction is poor, and they become slender.
⟧NL⟧2. Sand mouth: The sand mouth of wild sea cucumbers is large and hard. Flesh: Because wild sea cucumbers grow in deep water (15 to 20 m), where the water temperature is low and there is little sunlight, they grow slowly, their flesh is firm and elastic, their tendons are broad, thick and plump, and the nutrients deposited in them are abundant; pen-raised sea cucumbers, however, grow quickly, and their flesh is soft and not firm (this is very much like pigs sent to market at three months).
3. Shape: Wild sea cucumbers are spindle-shaped, pointed at both ends and thick in the middle, short, thick and plump, and look very sturdy; pen-raised sea cucumbers grow slender and lack toughness.

4. Back spines: The spines on the back and both sides of wild sea cucumbers are equally thick and strong, whereas in pen-raised sea cucumbers, because of the influence of the growing environment, the spines on the back and both sides may differ in thickness and length, and the long, slender spines give a feeling of lacking strength.
Growth years: Wild sea cucumbers Apostichopus japonicus generally grow for 4 to 5 years or more before reaching the standard for harvesting, and the longer the time, the more nutrients are deposited and the greater their tonic value; pen-raised sea cucumbers, however, are rapidly fattened in order to reach the market for sale quickly, and are harvested and sold in as little as one to two years, so their health tonic effect goes without saying. In addition, wild sea cucumbers have a chewy texture, no astringent taste, and fine, neat, uniform cut surfaces. As a rather expensive tonic delicacy, everyone is encouraged to pay attention to choosing wild sea cucumbers Apostichopus japonicus as the first choice for tonics and gifts, rather than blindly choosing quickly grown pen-raised sea cucumbers.