DIVE DRY WITH DR. BILL #736: GRUNT, GROWL AND HUM... HMMM
I received an e-mail from Jon Council with images of a fish taken off the backside of Catalina. They managed to disappear into cyberspace so I asked John King to forward them to me as they had been caught on his boat. I had never seen this fish, so I opened Dr. Milton Love's Certainly More Than You Want to Know About the Fishes of the Pacific Coast. I thought I found the right fish pretty quickly, thinking it was a plainfin midshipman (Porichthys notatus). I sent the images to Milton and he said "Close... but no cigar." If I'd turned the pages of his book a few more times, I might have discovered that it was a specklefin midshipman (Porichthys myriaster).
The specklefin midshipman and its relative are in the toadfish family, Batrachoididae. This somewhat rare species ranges from Point Arguello to at least Magdalena Bay in southern Baja, and has even been recorded from northern Peru. They may be found from the intertidal in colder northern waters to depths of over 400 ft.Milton says that during warm water events like El Niños, they tend to seek cooler water at slightly greater depths. They frequent nearshore habitats such as bays and estuaries but may also be found out in the open ocean. They live primarily over soft bottoms (but not those of babies) like sand or mud but may also be found in rocky areas. The midshipman may bury itself in the substrate during the day.
Specklefin midshipman have an elongated body and are brown with a hint of gold (but don't expect a treasure chest). They reach a maximum length of about 20 inches. The dorsal and pectoral fins have many small spots and bars which distinguishes them from the plainfin midshipman. The anal fin has a dark margin. Unlike most fish, the midshipman have four lateral lines. Highlighting them are four conspicuous rows of photophores or light emitting structures. The rows on the underside of the chin connect in front to form a U-shaped row.
Their eyes are on top of their large head, making vision easier when they are buried in the soft substrate. Looking into their mouth you are faced with a row of sharp canine teeth (although they are not related to dogs... nor am I). The spines on their operculum (gill cover) may be poisonous according to some sources.
As for "Munching," these fish are night time predators. They chow down on invertebrates such as crustaceans (shrimp, crab, amphipods and mysids) but add a little variety to their diet by taking small fish, cephalopods (octopus and squid) and even bivalve molluscs and echinoderms. Their mouths can open very wide to swallow large prey. The photophores produce a bluish-white light that is used to attract potential fish prey. In the grand scheme of The Mutual Eating Society, they are in turn fed upon by giant sea bass, sea lions, porpoises, larger shore birds and others.
No self-respecting Dive Dry column would neglect to discuss "Mating" which occurs during spring and summer (at least in this species). In April, May and June, these fish move into shallower water. They seek out nest sites in the reef or dig one in the soft substrate. The female attaches 200 to 400 eggs to the underside of a rock or in the soft bottom nest site. In true fish fashion, she splits town after a day or two and leaves the male behind to guard the eggs and young. He does not eat during this period which may last a month or more, and many of them may die even before the eggs hatch.
For those who question gender identity in humans, the midshipman poses an interesting example. It has three different genders. There are the ladies of course, but the males are divided into Type I and Type II. The two types differ in reproductive strategy. Type I males are much larger in size and have significantly larger vocal organs. Type II males have very large testes compared to their body size. Vocalizations are created using two muscles that act on the swim bladder. Females only grunt but Type I males may combine very short grunts with longer growls followed by hums that may last up to an hour. These noises may even awaken people living on house boats, so I'm glad my abode is up high on a hill!
© 2017 Dr. Bill Bushing. For the entire archived set of over 700 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Specklefin midshipman lateral and dorsal surfaces; ventral surface showing photophores and diagram of photophores (images courtesy of John King, Ashinado Charters).
I received an e-mail from Jon Council with images of a fish taken off the backside of Catalina. They managed to disappear into cyberspace so I asked John King to forward them to me as they had been caught on his boat. I had never seen this fish, so I opened Dr. Milton Love's Certainly More Than You Want to Know About the Fishes of the Pacific Coast. I thought I found the right fish pretty quickly, thinking it was a plainfin midshipman (Porichthys notatus). I sent the images to Milton and he said "Close... but no cigar." If I'd turned the pages of his book a few more times, I might have discovered that it was a specklefin midshipman (Porichthys myriaster).
The specklefin midshipman and its relative are in the toadfish family, Batrachoididae. This somewhat rare species ranges from Point Arguello to at least Magdalena Bay in southern Baja, and has even been recorded from northern Peru. They may be found from the intertidal in colder northern waters to depths of over 400 ft.Milton says that during warm water events like El Niños, they tend to seek cooler water at slightly greater depths. They frequent nearshore habitats such as bays and estuaries but may also be found out in the open ocean. They live primarily over soft bottoms (but not those of babies) like sand or mud but may also be found in rocky areas. The midshipman may bury itself in the substrate during the day.
Specklefin midshipman have an elongated body and are brown with a hint of gold (but don't expect a treasure chest). They reach a maximum length of about 20 inches. The dorsal and pectoral fins have many small spots and bars which distinguishes them from the plainfin midshipman. The anal fin has a dark margin. Unlike most fish, the midshipman have four lateral lines. Highlighting them are four conspicuous rows of photophores or light emitting structures. The rows on the underside of the chin connect in front to form a U-shaped row.
Their eyes are on top of their large head, making vision easier when they are buried in the soft substrate. Looking into their mouth you are faced with a row of sharp canine teeth (although they are not related to dogs... nor am I). The spines on their operculum (gill cover) may be poisonous according to some sources.
As for "Munching," these fish are night time predators. They chow down on invertebrates such as crustaceans (shrimp, crab, amphipods and mysids) but add a little variety to their diet by taking small fish, cephalopods (octopus and squid) and even bivalve molluscs and echinoderms. Their mouths can open very wide to swallow large prey. The photophores produce a bluish-white light that is used to attract potential fish prey. In the grand scheme of The Mutual Eating Society, they are in turn fed upon by giant sea bass, sea lions, porpoises, larger shore birds and others.
No self-respecting Dive Dry column would neglect to discuss "Mating" which occurs during spring and summer (at least in this species). In April, May and June, these fish move into shallower water. They seek out nest sites in the reef or dig one in the soft substrate. The female attaches 200 to 400 eggs to the underside of a rock or in the soft bottom nest site. In true fish fashion, she splits town after a day or two and leaves the male behind to guard the eggs and young. He does not eat during this period which may last a month or more, and many of them may die even before the eggs hatch.
For those who question gender identity in humans, the midshipman poses an interesting example. It has three different genders. There are the ladies of course, but the males are divided into Type I and Type II. The two types differ in reproductive strategy. Type I males are much larger in size and have significantly larger vocal organs. Type II males have very large testes compared to their body size. Vocalizations are created using two muscles that act on the swim bladder. Females only grunt but Type I males may combine very short grunts with longer growls followed by hums that may last up to an hour. These noises may even awaken people living on house boats, so I'm glad my abode is up high on a hill!
© 2017 Dr. Bill Bushing. For the entire archived set of over 700 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Specklefin midshipman lateral and dorsal surfaces; ventral surface showing photophores and diagram of photophores (images courtesy of John King, Ashinado Charters).
