Grass puffer


The grass puffer is a species of fish in the pufferfish family. This common to abundant species is found in the northwest Pacific Ocean in China, Japan, Korea, the Philippines and Vietnam. It is primarily found in coastal waters, ranging to depths of, but is often seen in brackish water and has also been recorded briefly entering freshwater. The grass puffer reaches up to in length.

Breeding

The grass puffer has a highly unusual breeding behavior where large groups gather seasonally in shallow water along certain beaches during high tide, throw themselves onto land where fertilization occurs, and then return to the water. The fertilized eggs may be swept back to the sea or stay on land under rocks for a period, but in the latter case they only hatch when submerged by water during a later high tide. Such a breeding behavior is not known from any other pufferfish, but is known from the unrelated capelin and grunion.

Relationship with humans

The grass puffer is often caught off beaches, docks, and piers using various baits such as worms, shrimp, sea lice, or cut fish. They are popular for children to catch, but their intestines contain the extremely potent pufferfish poison tetrodotoxin which is potentially lethal to humans. The species is not specifically targeted, but sometimes taken as part of the fugu fishery.