DIVE DRY WITH DR. BILL #773: SEXY SALPS
A few months ago, Catalina experienced an invasion of salps. What, you ask? Salps are invertebrates whose larvae possess a primitive nerve chord called a notochord. Due to this, they are classified as chordates along with fish, marine mammals... and human beings! Yes, they are our closest relatives that do not possess backbones.
To many, these salps resemble sea jellies (formerly known as jellyfish). Fortunately they do not possess stinging cells and are safe to touch (preferably when you find them dead on Catalina's beaches rather than while alive underwater). In fact I was able to collect a few from the beach and rinse them off in a salt water fountain so I could take pictures of them.
I've written previously of the giant pyrosome (Pyrosoma spinosum) observed in the dive park by several friends. Shortly after it was joined by the far more common fire salp known scientifically as Pyrosoma atlanticum. Now we biologists often come up with provocative, suggestive, libidinous, licentious and sometimes even lecherous names for marine critters. I'm no exception. My readers are probably aware that I refer to this species of fire salp as the "French tickler" for somewhat obvious reasons. Salps also have close relatives known as tunicates that live their lives attached to the ocean floor rather than drifting off to "see the world."
However, the dominant salp on that particular weekend was another species with the scientific name Thetys vagina (a name I'm not responsible for!). In my research on the scientific name, I noted a reference to a "sea monster" known as General Thetys on Wiki. However another source stated that the genus name Thetys came from Tethys of Greek mythology. A third source indicated it was derived from Thetis, a Naiad in Greek mythology that was the mother of Achilles. According to the first source, at the time of its discovery by Wilhelm Gottlieb Tilesius von Tilenau back in the very early 1800s, the word vagina also referred to a sheath as opposed to our common use of that word today. I was unaware of this species having a common name, but did find that some people call it an ocean gummy bear and others refer to it as the twin sailed salp.
T. vagina is found in warm oceans around the globe but can also be seen in cooler waters such as our own. Scripps indicates they can be found in the tropical and temperate waters of the Pacific, Atlantic and Indian Ocean. In my experience they are usually solitary or in small groups but in the recent case divers were saying there were up to a thousand in our dive park alone!
My research indicates that the species is the largest solitary salp, reaching a maximum length of about one foot, but I have actually observed chains of this species similar to the chains formed by other open water salps. Scripps confirmed that this species may be observed in both a solitary and an aggregate generation. Their barrel-shaped body is covered by a thick, somewhat rigid tunic. Their gut is located at the posterior end of the gelatinous body. Since they are translucent, divers can not only see into the gut but also observe the five bands of muscles ringing the body. There are two dark projections at the anterior end of the body.
This species chows down on single celled plankton and small crustaceans known as copepods. It filters them out as it cruises along in the water column, propelled by the muscular bands on the body. Water is sucked in the forward end and expelled out the other end. Although this is sufficient to feed, propulsion is somewhat weak and they generally drift along with the other plankton.
Although it may be orgasmic for them, the sex life of this salp is not very interesting compared to our mammalian mating mechanisms. However they do mix it up, reproducing by cloning and by sexual reproduction. The chained generation gets all the thrills while the solitary generation reproduces asexually (after all, it takes two to tangle). Of course there are a few lovely lady-go-divers I wish I could clone!
© 2018 Dr. Bill Bushing. For the entire archived set of nearly 775 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Solitary Thetys vagina (asexual generation, courtesy of Kathy Peper) and aggregate or colonial generation (sexual); soliary Thetys washed up on beach and colonial generation in open water.
A few months ago, Catalina experienced an invasion of salps. What, you ask? Salps are invertebrates whose larvae possess a primitive nerve chord called a notochord. Due to this, they are classified as chordates along with fish, marine mammals... and human beings! Yes, they are our closest relatives that do not possess backbones.
To many, these salps resemble sea jellies (formerly known as jellyfish). Fortunately they do not possess stinging cells and are safe to touch (preferably when you find them dead on Catalina's beaches rather than while alive underwater). In fact I was able to collect a few from the beach and rinse them off in a salt water fountain so I could take pictures of them.
I've written previously of the giant pyrosome (Pyrosoma spinosum) observed in the dive park by several friends. Shortly after it was joined by the far more common fire salp known scientifically as Pyrosoma atlanticum. Now we biologists often come up with provocative, suggestive, libidinous, licentious and sometimes even lecherous names for marine critters. I'm no exception. My readers are probably aware that I refer to this species of fire salp as the "French tickler" for somewhat obvious reasons. Salps also have close relatives known as tunicates that live their lives attached to the ocean floor rather than drifting off to "see the world."
However, the dominant salp on that particular weekend was another species with the scientific name Thetys vagina (a name I'm not responsible for!). In my research on the scientific name, I noted a reference to a "sea monster" known as General Thetys on Wiki. However another source stated that the genus name Thetys came from Tethys of Greek mythology. A third source indicated it was derived from Thetis, a Naiad in Greek mythology that was the mother of Achilles. According to the first source, at the time of its discovery by Wilhelm Gottlieb Tilesius von Tilenau back in the very early 1800s, the word vagina also referred to a sheath as opposed to our common use of that word today. I was unaware of this species having a common name, but did find that some people call it an ocean gummy bear and others refer to it as the twin sailed salp.
T. vagina is found in warm oceans around the globe but can also be seen in cooler waters such as our own. Scripps indicates they can be found in the tropical and temperate waters of the Pacific, Atlantic and Indian Ocean. In my experience they are usually solitary or in small groups but in the recent case divers were saying there were up to a thousand in our dive park alone!
My research indicates that the species is the largest solitary salp, reaching a maximum length of about one foot, but I have actually observed chains of this species similar to the chains formed by other open water salps. Scripps confirmed that this species may be observed in both a solitary and an aggregate generation. Their barrel-shaped body is covered by a thick, somewhat rigid tunic. Their gut is located at the posterior end of the gelatinous body. Since they are translucent, divers can not only see into the gut but also observe the five bands of muscles ringing the body. There are two dark projections at the anterior end of the body.
This species chows down on single celled plankton and small crustaceans known as copepods. It filters them out as it cruises along in the water column, propelled by the muscular bands on the body. Water is sucked in the forward end and expelled out the other end. Although this is sufficient to feed, propulsion is somewhat weak and they generally drift along with the other plankton.
Although it may be orgasmic for them, the sex life of this salp is not very interesting compared to our mammalian mating mechanisms. However they do mix it up, reproducing by cloning and by sexual reproduction. The chained generation gets all the thrills while the solitary generation reproduces asexually (after all, it takes two to tangle). Of course there are a few lovely lady-go-divers I wish I could clone!
© 2018 Dr. Bill Bushing. For the entire archived set of nearly 775 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Solitary Thetys vagina (asexual generation, courtesy of Kathy Peper) and aggregate or colonial generation (sexual); soliary Thetys washed up on beach and colonial generation in open water.
