Most people are familiar with the types of shrimp they see on their plate, but the term shrimp is a broad term that refers to any of about 2,000 species of small (as tiny as a fingernail to over eight inches long), water-dwelling animals. Shrimp are in the same family as crabs, lobsters and crayfish and live in a variety of climates, bodies of water and habitats. Because shrimp breed rapidly, they can be harvested more often than some other species. However, even shrimp fishing has its limits, and some parts of the world are showing signs of overharvesting.
Shrimp reproduction begins soon after a female has molted. In some species, a male shrimp will seek out a female that is ready to molt and guard her as his own until she is ready to mate, protecting her from other males. When she is, the pair will lock together and copulate for several seconds and then swim together for hours or even days. In others, the male is seemingly unable (or finds it unnecessary) to recognize a pre-molt female. Instead, he interacts with as many females as needed until he finds one that is ready to mate. In these cases, the male and female separate quickly after copulation. During copulation, the female produces a gelatinous mass and holds it between her fourth pair of walking legs for the male to deposit sperm into it. Next, the female lays as many as 15,000 eggs in the gelatin for the sperm to fertilize. In most species, the female will care for the fertilized eggs in what is called a brood chamber that is located on the underside of her tail. However, some species will scatter their eggs in the water to develop on their own.
When the eggs hatch, they produce drifting larvae. The larvae go through several shape changes as they grow, molting their skin several times until they develop an adult body. Once the transformation is complete and the larvae have developed into adults (a process that takes 30 to 160 days, depending on the species), the young shrimp are already sexually mature and capable of breeding.
Shrimp are found in all of the oceans across the globe, freshwater lakes and streams. Most open-water ocean-dwelling species live near the surface, but some are found on the ocean floor or on coral reefs.
Not only are shrimp a popular and delicious food for humans, but shrimp are an important part of the food chain in their natural habitats. Shrimp are food for many other animals, and they in turn eat microorganisms in the water and bits of dead sea life on the ocean floor. Three million tons of shrimp are harvested each year from the wild and shrimp farms, so it is fortunate that they reproduce so quickly.
If the rate of shrimp harvesting overtakes the shrimps'' ability to reproduce, there will be a shortage of shrimp for human consumption.