DIVE DRY WITH DR. BILL #779: BETWEEN TWO WORLDS
Many years ago, almost before my memory cells kick in, one of my teaching assistants at the Catalina Island School made a very interesting observation. It involved communication between two different worlds. No, I'm not referring to SETI and a message from my friends on the planet Xanadu. I'm talking about an exchange between a largely "terrestrial" critter and a distinctly marine one.
Barry Aires had been one of my high school students and had one of the best eyes I've seen for noting unusual events in the marine world. He returned after graduation to serve as one of my teaching assistants along with another former student of mine, Packy Offield. They mainly helped with my many field trips around the island and out on the ocean.
One of my field ecology labs involved going out in the school launch, the venerable K.V. (named after the school's founder, Keith Vosburg), looking for drifting kelp (Macrocystis pyrifera) paddies. Now many anglers search for these hoping to hook a yellowtail or other fish following the kelp raft. We focused on capturing the kelp holdfasts in large plastic trash bags to take back to my marine biology lab at Toyon Bay.
Once back in the lab my students and I would "dissect" the kelp holdfast and tweeze out all the critters that were hitching a ride on it. Some traveled from the mainland to the island and several were on holdfasts of bull kelp (Nereocystis luetkeana), a species of kelp found only north of Pt. Conception. These rafts proved that kelp could transport critters over regional scales. My Kiwi mentor at Harvard, Dr. Barry Fell, had shown that kelp in the southern hemisphere could probably transport invertebrates over distances of thousands of miles!
One day Barry was out in the K.V. and observed something quite unusual. There was an ocean sunfish (Mola mola) at the surface flapping its dorsal fin. After doing so, the sunfish rotated 90° and laid horizontally at the surface. Barry saw a Heerman's gull (Larus heermanni) resting nearby. The gull paddled over to the sunfish and began using its beak on the Mola's fins. It was cleaning parasites off the fish!
The gull swam away and the sunfish repeated the flapping of its dorsal fin. The gull swam back and proceeded to clean again. When Barry described this to me back at the school, I was astounded. This was the first observation any of my team had made of communication between a marine fish and a largely terrestrial bird. It was later observed again on a few occasions.
Back then (mid- to late-1970s) I was working as a biologist on Jean-Michel Cousteau's Project Ocean Search Catalina program based at my school. Dr. Milton Love was also involved in the program and I told him about our observations. Milton later published a paper on a similar interaction he had observed. This indicated our sightings were not just some local fluke, but a more widespread phenomenon.
In my research for this column I noted that National Geographic's web site indicated ocean sunfish are hosts to a variety of skin parasites, as many as forty different species. That could be quite a feast for a hungry cleaner. Their website also had a brief video segment of a sunfish being cleaned by another species of gull near a kelp raft although it didn't show the fin flapping solicitation.
Now communication between cleaners and host species is not unusual. It happens in both terrestrial and aquatic environments. On almost every dive in our waters I've observed blacksmith (Chromis punctipinnis) and occasionally garibaldi (Hypsypops rubicundus) soliciting cleaning behavior from señorita (Oxyjulis californica) and rock wrasse (Halichoeres semicinctus). Solicitation between hosts and cleaners is also quite common in semi-tropical and tropical waters (where I prefer to dive in the harsh, cold southern California winters... tee hee).
While diving Farnsworth Bank back in June of 2007, I witnessed another episode with a Mola being cleaned. This time it wasn't by a seagull, but by another fish. I was on my safety stop about 40 ft above the highest pinnacle when I saw a pair of sunfish swimming near me. I was surprised to see a halfmoon (Medialuna californiensis) swim over to one of the sunfish, inspect it and begin picking what appeared to be parasites off it. I often see halfmoon soliciting cleaning from rock wrasse in the dive park. However, it was quite interesting to see the halfmoon kind of returning the favor by cleaning a Mola. Pay it forward.
So communication between the terrestrial and marine environments is possible, especially when the symbiotic interaction is beneficial to both species. If they can find a way to share information, why can't we? At times it seems humans can barely interact with other humans in a mutually respectful and beneficial way. If we can't do that, how are we going to do so with advanced civilizations like my friends from the planet Xanadu?
© 2018 Dr. Bill Bushing. For the entire archived set of more than 775 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Pair of Mola mola and halfmoon inspecting a Mola; Mola lying horizontally at the surface and Heerman's gull.
Many years ago, almost before my memory cells kick in, one of my teaching assistants at the Catalina Island School made a very interesting observation. It involved communication between two different worlds. No, I'm not referring to SETI and a message from my friends on the planet Xanadu. I'm talking about an exchange between a largely "terrestrial" critter and a distinctly marine one.
Barry Aires had been one of my high school students and had one of the best eyes I've seen for noting unusual events in the marine world. He returned after graduation to serve as one of my teaching assistants along with another former student of mine, Packy Offield. They mainly helped with my many field trips around the island and out on the ocean.
One of my field ecology labs involved going out in the school launch, the venerable K.V. (named after the school's founder, Keith Vosburg), looking for drifting kelp (Macrocystis pyrifera) paddies. Now many anglers search for these hoping to hook a yellowtail or other fish following the kelp raft. We focused on capturing the kelp holdfasts in large plastic trash bags to take back to my marine biology lab at Toyon Bay.
Once back in the lab my students and I would "dissect" the kelp holdfast and tweeze out all the critters that were hitching a ride on it. Some traveled from the mainland to the island and several were on holdfasts of bull kelp (Nereocystis luetkeana), a species of kelp found only north of Pt. Conception. These rafts proved that kelp could transport critters over regional scales. My Kiwi mentor at Harvard, Dr. Barry Fell, had shown that kelp in the southern hemisphere could probably transport invertebrates over distances of thousands of miles!
One day Barry was out in the K.V. and observed something quite unusual. There was an ocean sunfish (Mola mola) at the surface flapping its dorsal fin. After doing so, the sunfish rotated 90° and laid horizontally at the surface. Barry saw a Heerman's gull (Larus heermanni) resting nearby. The gull paddled over to the sunfish and began using its beak on the Mola's fins. It was cleaning parasites off the fish!
The gull swam away and the sunfish repeated the flapping of its dorsal fin. The gull swam back and proceeded to clean again. When Barry described this to me back at the school, I was astounded. This was the first observation any of my team had made of communication between a marine fish and a largely terrestrial bird. It was later observed again on a few occasions.
Back then (mid- to late-1970s) I was working as a biologist on Jean-Michel Cousteau's Project Ocean Search Catalina program based at my school. Dr. Milton Love was also involved in the program and I told him about our observations. Milton later published a paper on a similar interaction he had observed. This indicated our sightings were not just some local fluke, but a more widespread phenomenon.
In my research for this column I noted that National Geographic's web site indicated ocean sunfish are hosts to a variety of skin parasites, as many as forty different species. That could be quite a feast for a hungry cleaner. Their website also had a brief video segment of a sunfish being cleaned by another species of gull near a kelp raft although it didn't show the fin flapping solicitation.
Now communication between cleaners and host species is not unusual. It happens in both terrestrial and aquatic environments. On almost every dive in our waters I've observed blacksmith (Chromis punctipinnis) and occasionally garibaldi (Hypsypops rubicundus) soliciting cleaning behavior from señorita (Oxyjulis californica) and rock wrasse (Halichoeres semicinctus). Solicitation between hosts and cleaners is also quite common in semi-tropical and tropical waters (where I prefer to dive in the harsh, cold southern California winters... tee hee).
While diving Farnsworth Bank back in June of 2007, I witnessed another episode with a Mola being cleaned. This time it wasn't by a seagull, but by another fish. I was on my safety stop about 40 ft above the highest pinnacle when I saw a pair of sunfish swimming near me. I was surprised to see a halfmoon (Medialuna californiensis) swim over to one of the sunfish, inspect it and begin picking what appeared to be parasites off it. I often see halfmoon soliciting cleaning from rock wrasse in the dive park. However, it was quite interesting to see the halfmoon kind of returning the favor by cleaning a Mola. Pay it forward.
So communication between the terrestrial and marine environments is possible, especially when the symbiotic interaction is beneficial to both species. If they can find a way to share information, why can't we? At times it seems humans can barely interact with other humans in a mutually respectful and beneficial way. If we can't do that, how are we going to do so with advanced civilizations like my friends from the planet Xanadu?
© 2018 Dr. Bill Bushing. For the entire archived set of more than 775 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Pair of Mola mola and halfmoon inspecting a Mola; Mola lying horizontally at the surface and Heerman's gull.
