DIVE DRY WITH DR. BILL #850: A FROG WENT A'SWIMMING
This California winter has been bitter cold, almost as bad as winter in Chicago when it hit 81° below with the wind chill. At least back then I was nice and warm in my parent's house with the furnace running 24/7. This winter I've had to wear a down parka inside my house when it was in the low-50° range. Along with the wind chill, there was a very noticeable impact due to the high humidity from living by the ocean. Back in the mid-1970s when my parents were visiting me on Catalina, they claimed it was the coldest night they'd ever spent indoors.
Hmmm, so why am I writing about cold weather instead of marine critters? Well, because it makes me wish I could return to some warm destination like Palau, the Philippines or Australia! So I'm going to try to warm up by writing about a tropical group of fish I filmed in the 84-87° waters of Anilao and Puerto Galera in the Philippines. I'm referring to members of the frogfish family, Antennariidae.
Actually according to fish expert Dr. Milton Love, we have one species that can be found from Santa Catalina Island (at the northernmost end of their range) south to Chile. It is the roughjaw frogish (Antennarius avalonis). Its species name, avalonis, is due to the fact the first specimen was taken from the waters near my town of Avalon. Milton refers to it as an occasional sighting here during warm water periods. I have never had the fortune to find and film one of these... and water temperatures today (February) were a not very enticing 58 degrees (warm for this time of year).
Frogfish are also known as anglerfish, especially in the waters down under in Australia. One distinctive feature is their angling lure, known as the esca, extending above the mouth to attract its fish prey. The lure and its stalk are actually a modified dorsal fin spine. The lure is distinctive in each species and is used by scientists to tell them apart. Some resemble small fish, others worms or shrimp or squid. This is important because color may be highly variable within a given species. Based on my research for this column, there are an estimated 46 to 60 species in the world, almost all of them in tropical and sub-tropical waters.
Their bodies are hardly streamlined for swimming, since they rarely do that. They "walk" about the bottom on their modified pectoral fins. While most of the ones I found moved like this, I was fortunate to film one giant frogfish actually swimming in the water column. These species lack a swim bladder which is critical in most fishes. Frogfish bodies are high backed and lack scales. The body shape helps make it difficult for potential predators to see them, and they often display coloration that mimics the environment they live in. To accomplish this many frogfish species are able to change color over a period of days to weeks.
Frogfish are ambush predators. Their diet includes other fish, crustaceans and on occasion they become cannibals. Like our giant sea bass, they suction feed. By quickly opening their upturned mouths, they create a vacuum that draws prey inside once it has been attracted by the lure. According to Wikipedia they can also enlarge their stomachs to accommodate prey twice their own size. I have accomplished something similar recently due to the incredible selection of edibles in our new Vons grocery store!
There doesn't appear to be any highly stylized mating ritual in these species. Apparently as spawning approaches, the female's abdomen expands as her many eggs absorb water. During this time the male approaches the female and hangs near her. When its time for the climax, the female swims toward the surface followed closely by her mate. This allows the eggs to disperse in the currents. However some species actually lay their eggs on the bottom.
Moving on to the Philippines, I was blessed to see a number of frogfish species, often pointed out by my excellent dive guide in Anilao, Ben Castillo. That was a great help as my eyes could not always see the highly camouflaged ones. Some were rather small like the multi-colored warty frogfish (Antennarius maculatus) and painted frogfish (Antennarius pictus). The largest one I saw was a green giant (no relation to green giant veggies) frogfish (Antennarius commersoni) which was the one individual I filmed while it was swimming. Sadly Ben found one hairy or striated frogfish (Antennarius striatus) that had been unintentionally killed by a group of rather careless divers.
Well, my hands are shaking from the cold as I type this. In the distance, some 90 miles away, I can see snow atop the San Gabriel Mountains. Okay, so it isn't Chicago... but my blood has thinned a lot since I moved here nearly 50 years ago! But I can still think warm thoughts as I go through my underwater photo galleries from tropical waters. Sigh.
© 2020 Dr. Bill Bushing. For the entire archived set of over 800 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Two color variants of the warty frogfish showing the mouth and modified pectoral fins; can you see the frogfish in this image and the jolly green giant froggie swimming away.
This California winter has been bitter cold, almost as bad as winter in Chicago when it hit 81° below with the wind chill. At least back then I was nice and warm in my parent's house with the furnace running 24/7. This winter I've had to wear a down parka inside my house when it was in the low-50° range. Along with the wind chill, there was a very noticeable impact due to the high humidity from living by the ocean. Back in the mid-1970s when my parents were visiting me on Catalina, they claimed it was the coldest night they'd ever spent indoors.
Hmmm, so why am I writing about cold weather instead of marine critters? Well, because it makes me wish I could return to some warm destination like Palau, the Philippines or Australia! So I'm going to try to warm up by writing about a tropical group of fish I filmed in the 84-87° waters of Anilao and Puerto Galera in the Philippines. I'm referring to members of the frogfish family, Antennariidae.
Actually according to fish expert Dr. Milton Love, we have one species that can be found from Santa Catalina Island (at the northernmost end of their range) south to Chile. It is the roughjaw frogish (Antennarius avalonis). Its species name, avalonis, is due to the fact the first specimen was taken from the waters near my town of Avalon. Milton refers to it as an occasional sighting here during warm water periods. I have never had the fortune to find and film one of these... and water temperatures today (February) were a not very enticing 58 degrees (warm for this time of year).
Frogfish are also known as anglerfish, especially in the waters down under in Australia. One distinctive feature is their angling lure, known as the esca, extending above the mouth to attract its fish prey. The lure and its stalk are actually a modified dorsal fin spine. The lure is distinctive in each species and is used by scientists to tell them apart. Some resemble small fish, others worms or shrimp or squid. This is important because color may be highly variable within a given species. Based on my research for this column, there are an estimated 46 to 60 species in the world, almost all of them in tropical and sub-tropical waters.
Their bodies are hardly streamlined for swimming, since they rarely do that. They "walk" about the bottom on their modified pectoral fins. While most of the ones I found moved like this, I was fortunate to film one giant frogfish actually swimming in the water column. These species lack a swim bladder which is critical in most fishes. Frogfish bodies are high backed and lack scales. The body shape helps make it difficult for potential predators to see them, and they often display coloration that mimics the environment they live in. To accomplish this many frogfish species are able to change color over a period of days to weeks.
Frogfish are ambush predators. Their diet includes other fish, crustaceans and on occasion they become cannibals. Like our giant sea bass, they suction feed. By quickly opening their upturned mouths, they create a vacuum that draws prey inside once it has been attracted by the lure. According to Wikipedia they can also enlarge their stomachs to accommodate prey twice their own size. I have accomplished something similar recently due to the incredible selection of edibles in our new Vons grocery store!
There doesn't appear to be any highly stylized mating ritual in these species. Apparently as spawning approaches, the female's abdomen expands as her many eggs absorb water. During this time the male approaches the female and hangs near her. When its time for the climax, the female swims toward the surface followed closely by her mate. This allows the eggs to disperse in the currents. However some species actually lay their eggs on the bottom.
Moving on to the Philippines, I was blessed to see a number of frogfish species, often pointed out by my excellent dive guide in Anilao, Ben Castillo. That was a great help as my eyes could not always see the highly camouflaged ones. Some were rather small like the multi-colored warty frogfish (Antennarius maculatus) and painted frogfish (Antennarius pictus). The largest one I saw was a green giant (no relation to green giant veggies) frogfish (Antennarius commersoni) which was the one individual I filmed while it was swimming. Sadly Ben found one hairy or striated frogfish (Antennarius striatus) that had been unintentionally killed by a group of rather careless divers.
Well, my hands are shaking from the cold as I type this. In the distance, some 90 miles away, I can see snow atop the San Gabriel Mountains. Okay, so it isn't Chicago... but my blood has thinned a lot since I moved here nearly 50 years ago! But I can still think warm thoughts as I go through my underwater photo galleries from tropical waters. Sigh.
© 2020 Dr. Bill Bushing. For the entire archived set of over 800 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Two color variants of the warty frogfish showing the mouth and modified pectoral fins; can you see the frogfish in this image and the jolly green giant froggie swimming away.
