This is the time of year when the lucky nocturnal visitor to Bay shallows can hear the male toadfish, or midshipman (Porichthys notatus), calling for a mate. This well-known fish is found in shallow areas in San Francisco Bay and along the outer coast from Alaska to the Gulf of California. A brownish, 15-inch long body characterizes the midshipman, along with its rows of photophores (whitish dots) along the head and body.
The photophores glow during courtship – though you won’t see them unless you’re a scuba diver – which reminds some people of the buttons on a midshipman’s coat.
Midshipman bury themselves in sand or mud in the intertidal zone during the day and emerge from the mud at night. During the breeding season in late spring and summer, the males dig nests and produce a humming sound at night to attract females. The sound is loud enough that you’ll hear it if you’re nearby, and is the source of the strange singing sounds that houseboat residents often hear.
The female midshipman is stimulated by the sound and lays eggs in the humming male’s nest. The male then fertilizes the eggs and guards the nest for a month or more until the eggs hatch, forgoing all food during the incubation period. Listen for the male’s song this summer to hear one species’ musical approach to reproduction.