Porichthys notatus

Northern boatman fish ( Porichthys notatus )

The Northern boatman fish ( Porichthys notatus ) is a representative of the frog fish ( Batrachoididae ) which occurs on the Pacific coast of North America from Alaska to Baja California. There are two separate populations, one in Oregon and north of it, the other south of San Francisco. In the intermediate zone only a few copies have been spotted.

Features

The Northern boatman fish up to 38 cm long and is of olivbrauner to bronze color. Some specimens shimmering purple on the top, the bottom is bright, sometimes golden. Under the eye is a white arc-shaped spot, including a black. Juveniles have a hazy, dark, sattelfömigen spot on the back. The pectoral fins are broad, the caudal fin small and rounded. In contrast to Porichthys myriaster the fins are unspotted. The number of Branchiostegalstrahlen is six. The light-emitting members at the bottom of the head are arranged in a V -shape.

Fins formula: Dorsal II/33-37, Anal 30-35.

Way of life

Northern boatman fish live from the intertidal zone where adult animals hidden the ebb and outside the water, under stones and seaweed and air breathing, can survive at depths below 350 meters on sand and mud bottoms. Full-grown fish lead boatman at night by vertical migrations. They feed on crustaceans and small fish. They are oviparous. Is spawned mainly in bays. The nest is guarded by the male in a house built of stone nest.

Boatswain fish are an important food for California sea lions and harbor seals.

Lute

The male of Northern boatswain attracts fish during the spawning season with loud hum females and tries to encourage them to lay eggs. If some males are relatively close to each other, this hum can even bring boat walls to vibrate. Thus, the boatman fish whether his own Balzrufes is not deaf or hard of hearing, sound production and hearing of the same brain region can be controlled. While he created with the swim bladder an audible vibrato ( about 100 Hz ), at the same time a signal is sent to the hair cells of his ear, which significantly reduces their sensitivity to noise.

The mating call, however, can only attract females carrying eggs befruchtbare in itself. This is due to that are " open ears " at boatswain fish females only at elevated estrogen levels. The females look at males that buzz very loud and long ( up to one hour ), which they also show again their hormonal status.