Please allow me to introduce to you, a little fish that lights up and sings! I first heard the singing midshipman while anchored in Glorietta Bay, San Diego – right off the 18th tee. Each night we’d heard a droning hum that went on for hours. It wasn’t a hummmm, but more a popm, popm, popm and we had no idea what it was. Then, years later, I was reading about fish and bioluminescence – not the microscopic stuff that lights up our waters in summer, but bigger creatures that light up to attract a mate. The two experiences suddenly came together into one critter, the plainfin midshipman, named for the luminescent ‘uniform buttons’ on its skin. About hand-sized, the southern species of fish ‘light up’ during courtship because they eat a crustaceon that has the light-up chemical, but Salish Sea midshipman don’t eat that, so they’re perpetually in the dark.
Both male and female midshipman sing their songs during courtship or while fighting, but the male’s courtship call is more a prolonged hum. Sometimes it can go on for over an hour without a break. This is produced using muscles in its modified swim bladder. Fish have internal ears but they don’t exactly ‘hear’ sounds like we do. Instead, they pick up vibrations coming through the water – which is what these midshipman are doing to find each other. When a male makes its song that’s somewhat like a radio with a short in it, females move towards him, and during mating season in summer, hormones increase the females ‘hearing’ so that she can better sense the male’s calls. Next time you’re in a quiet anchorage, put an empty glass to the hull or cabin bulkhead and have a long listen. Hear the midshipman’s siren calling for his true love?
Larry Eifert paints and writes about the Pacific Northwest from Port Townsend. His large-scale murals can be seen in many national parks across America, and at larryeifert.com.
***previous*** — ***next***