Baby Eels Are Elvers and Baby Oysters Are Spats

The ocean has its own peculiar baby naming conventions, and two of the most charming examples are elvers and spats. While most people stick to generic terms like "baby fish" or "baby shellfish," marine biologists have blessed these tiny creatures with names that sound almost magical.

An elver is a young eel, specifically one that's migrating upstream from the ocean into fresh or brackish water. Before becoming elvers, eels start life as transparent larvae drifting in the ocean. They transform into equally transparent "glass eels" before developing pigmentation and earning the name elver. The term dates back to around 1640 and comes from "eelfare," literally referring to the eel's journey.

The Incredible Eel Migration

Elvers undertake one of nature's most remarkable journeys. Born in the ocean, they travel thousands of miles to reach freshwater rivers and streams where they'll mature. This upstream migration is so predictable that elvers have become commercially valuable—fishermen catch them to sell as seedstock to Asian aquaculture companies.

These little swimmers face incredible odds. They navigate by instinct, wriggling through obstacles and even across wet grass if necessary to reach their destination. Once there, they'll spend years growing into adult eels before eventually returning to the ocean to spawn.

Spat: Not What You Think

Meanwhile, spat refers to baby oysters, though the name applies specifically after a crucial life change. Oyster larvae float freely in the water until they find a suitable hard surface—often an old oyster shell. Once they attach themselves, they're officially spat.

A single recycled oyster shell can host about ten spat on average. They remain spat until they grow beyond 25 millimeters (about one inch) in length. The term has been around since at least the 14th century, though why baby oysters received this particular name remains a linguistic mystery.

Why the Fancy Names?

These specialized terms serve practical purposes in marine biology and aquaculture. When researchers discuss eel life stages, distinguishing between larvae, glass eels, elvers, and adults helps pinpoint exactly which developmental phase they're studying. Similarly, oyster restoration projects track spat survival rates to measure success.

But there's something delightful about these names beyond their scientific utility. They remind us that the ocean harbors countless small wonders, each with its own terminology and story. The naming traditions also reflect centuries of human observation—fishermen and scientists needed words to describe what they were seeing, and somehow "elver" and "spat" stuck.

Other sea creatures have equally charming baby names: baby jellyfish are ephyrae, baby seahorses are fry, and baby crabs go through a zoea stage. The ocean's nursery has a vocabulary all its own.