DIVE DRY WITH DR. BILL #738: BENNY THE BLENNY GETS A BABE
Perhaps a year ago I reported on the discovery of a fish I had not seen in the dive park before. Other local divers had seen it and I tentatively identified it as a male largemouth blenny (Labrisomus xanti). Fish expert Dr. Milton Love confirmed it was most likely that species, although it could possibly be a related one. Dive buddy Catherine Ngo named it Benny the Blenny.
When I was able to resume my diving this year following my months in the hospital, I located other individuals believed to be of this species. Many of them appeared to be females with a more camouflaged appearance. Normally the largemouth blenny is a more southern species, found from Vizcaino Bay on the Pacific coast of Baja throughout the Sea of Cortez to Tenacatita Bay in Jalisco, Mexico. It apparently made the jump from south of the border to our waters during the recent warm water spell.
The species was first noted down in La Jolla back in July, 2015. Janna Nichols was the first to observe the largemouth blenny in Catalina waters in late October of that year. These fish are strongly territorial and stick close to the reef in shallow water. Since I'm such a "deep" guy, I didn't see it until the following spring.
Now range extensions such as this are not entirely unusual. When ocean temperatures change, critters may move north or south of their normal geographic range. After water temperature becomes more normal, they have to be able to survive the conditions in their new habitats. If so, a species may persist in a new location until the individuals die.
However to permanently extend its range, it must find conditions in the new location suitable for reproduction as well. Often individuals may survive in their newly colonized areas, but find conditions unsuitable to successfully mate. Dive instructor Ruth Harris and I have seen several pairs of largemouth blennies, so perhaps reproduction will occur in our waters!
The largemouth blenny frequents shallow water, which is where I've seen all the ones I've observed. While the male tends to be aggressive when I approach, the female is often skittish and seeks shelter in the rocks. I never knew I could be so intimidating to the ladies! Males are bolder and I often see them out in the open... at least until I press the record button on my video camera!.
These blennies are daytime predators, coming out of their nooks and crannies to feed on bottom dwelling crustaceans such as crabs. The red coloration that is common especially during breeding season probably serves to hide them at night as red light does not penetrate water to any great depth, thus making them appear dark.
This is a small fish, generally no longer than about seven inches. Although individuals may be greenish-brown in color with eight dark bars along the side, when they get "the urge to merge" males turn reddish in color and possess a large black spot between the second and fourth dorsal spines. I sometimes turn red when the subject of mating comes up myself!
© 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: Male largemouth blennies (top) and the ladies (bottom).
Perhaps a year ago I reported on the discovery of a fish I had not seen in the dive park before. Other local divers had seen it and I tentatively identified it as a male largemouth blenny (Labrisomus xanti). Fish expert Dr. Milton Love confirmed it was most likely that species, although it could possibly be a related one. Dive buddy Catherine Ngo named it Benny the Blenny.
When I was able to resume my diving this year following my months in the hospital, I located other individuals believed to be of this species. Many of them appeared to be females with a more camouflaged appearance. Normally the largemouth blenny is a more southern species, found from Vizcaino Bay on the Pacific coast of Baja throughout the Sea of Cortez to Tenacatita Bay in Jalisco, Mexico. It apparently made the jump from south of the border to our waters during the recent warm water spell.
The species was first noted down in La Jolla back in July, 2015. Janna Nichols was the first to observe the largemouth blenny in Catalina waters in late October of that year. These fish are strongly territorial and stick close to the reef in shallow water. Since I'm such a "deep" guy, I didn't see it until the following spring.
Now range extensions such as this are not entirely unusual. When ocean temperatures change, critters may move north or south of their normal geographic range. After water temperature becomes more normal, they have to be able to survive the conditions in their new habitats. If so, a species may persist in a new location until the individuals die.
However to permanently extend its range, it must find conditions in the new location suitable for reproduction as well. Often individuals may survive in their newly colonized areas, but find conditions unsuitable to successfully mate. Dive instructor Ruth Harris and I have seen several pairs of largemouth blennies, so perhaps reproduction will occur in our waters!
The largemouth blenny frequents shallow water, which is where I've seen all the ones I've observed. While the male tends to be aggressive when I approach, the female is often skittish and seeks shelter in the rocks. I never knew I could be so intimidating to the ladies! Males are bolder and I often see them out in the open... at least until I press the record button on my video camera!.
These blennies are daytime predators, coming out of their nooks and crannies to feed on bottom dwelling crustaceans such as crabs. The red coloration that is common especially during breeding season probably serves to hide them at night as red light does not penetrate water to any great depth, thus making them appear dark.
This is a small fish, generally no longer than about seven inches. Although individuals may be greenish-brown in color with eight dark bars along the side, when they get "the urge to merge" males turn reddish in color and possess a large black spot between the second and fourth dorsal spines. I sometimes turn red when the subject of mating comes up myself!
© 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: Male largemouth blennies (top) and the ladies (bottom).
