Seanniver

Splitting from its ancestor, Ray Flat Swarmers would migrate from coastal environments into the open oceans of Sagan 4.

Seannivers are pelagic suspension feeders which eat a wide variety of plankton. It also gains energy from photosynthesizing through its skin. Seannivers inhabit warm, tropical and subtropical open waters near the equator, staying near the water’s surface. The year-round sun and plentiful plankton populations in these environments allow Seannivers to maximize productivity from its feeding strategies. It has a flattened body, with its large fins being wider than the length of its body, which further allows them to take in solar energy.

Like its ancestors, Seannivers are social animals which live in swarms of hundreds of individuals. These large swarms do allow safety in numbers, but can also warn members of danger before a predator even attacks. Seannivers alternate behavior between swimming right side up near the surface and upside down in deeper water. While swimming right side up, Seannivers harvest sunlight more easily. While swimming upside down, it is able to see predators from below with its singular eye, darting to the surface and warning right side up members of the nearby predator.

A Seanniver primarily feeds through suspension, swimming forward and allowing water to flow into the mouth along with prey. Due to having a blind gut, a Seanniver has no way to passively filter out water. Instead, after harvesting enough prey it partially closes its mouth and begin compressing its stomach using slight muscular contractions. The interior of a Seanniver's mouth is covered in villi, allowing small amounts of water to exit while most plankton remain trapped in the tightening gut. This strategy tends to be more effective at capturing larger organisms, while smaller ones may still escape. These villi have the added advantage of slightly increasing the Seanniver's surface area which increases oxygenation. Seannivers primarily feed on phytoplankton, such as Redmosses and Testudiatoms, and may also feed on zooplankton and larval young of other organisms. When not feeding, a Seanniver with its mouth closed is much more hydrodynamic, and can lazily glide along the surface while photosynthesizing or quickly evade predators.

Seeking out the most food in an environment where it is often hard to come by, Seannivers congregate near upwelling locales plentiful with plankton. Seannivers will also spawn en masse in these areas, each female releasing thousands of eggs into the current every summer.