Shiner Perch

• It does not lay eggs: it is viviparous and gives birth to large, fully formed young that swim from the first moment.
• The males are born already sexually mature and can fertilise a female within days of birth, although the embryos do not begin to develop until months later.
• It is one of the most widely used indicator species for the health of North American Pacific estuaries.
• It is viviparous, something exceptional among temperate marine fishes: the embryos develop inside the female and are born fully formed, at a size that can reach a third of the mother's.
• And it goes further: the embryo's fins are highly vascularised and absorb nutrients from the ovarian fluid, a mechanism comparable to that of a placenta.
• Males are born already sexually mature and can mate in their first year, while females store the sperm for months before fertilisation takes place.
• It forms large schools in estuaries and under piers, and is one of the most abundant and best-studied species of the Pacific's eelgrass meadows.

Skeleton type

Vertebrate - internal bony skeleton (bony fish)

Habitat and environment

Eelgrass beds, piers and bays of the north-eastern Pacific

Gestation / incubation

3-6 months of internal gestation

Sources consulted: Wikipedia (en): Shiner perch