Fish & Water - Sounds Wild
Shrimp Sex Change

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Hermaphroditic shrimp

A boat idles in a cove on a summer afternoon, pulling up a set of shrimp pots. The first one comes in with a nice catch of spot shrimp. Spot shrimp are the biggest shrimp in the North Pacific and are highly valued by commercial pot fishers and subsistence users alike.

Spot shrimp, along with pink, coonstripe and humpy shrimp, are one of five species of pandalid shrimp found in the cool waters off the coast of Alaska. Pandalid shrimp are one of the rare hermaphroditic animals. They change their sex. Specifically, they are protandrous hermaphrodites - the shrimp spends the early part of its adult life as a male and then changes into a female for the rest of its lifetime. A pink shrimp will typically mature sexually as a male, spawn one or more times, pass through a short transitional phase and subsequently mature and spawn as a female.

Shrimp spawn in the fall and the eggs incubate over the winter. In the spring the eggs hatch into planktonic, free-swimming larvae. By mid-summer, the larvae have undergone several molts, rapidly increasing in size after each molt. After the last larval molt the juvenile shrimp settles to the bottom. After a year or so, the juvenile molts and develops into a mature male and may spawn as a male for one or two seasons. Some juveniles, however, never mature into males; instead, they develop directly into females.