28. Jun, 2017

Profile of the Blenny

Blennies belong to the suborder of Blennioids, or ‘slimy’ fishes according to the Greek τό βλέννος that stands for mucus or slime. Together the Blennoids form a incredibly large number of small fish species, that are often hard to tell apart at first sight. No wonder one gets easily confused! One way for not getting lost in the labyrinth is to follow the taxonomy: Order--Family-- Genus--Species. The Blennoids consist of six families. The largest and best known family are the Blenniidae also known as Combtooth or Scaleless blennies, that contains around 50 genera and  400 known species.  They are followed by  two other large families:  the Clinidae or Scaled blennies found in all oceans, and the Chaenopsidae, a strictly tropical family, ranging from North to South America. Then we have the Tripterygiidae or threefin blennies  a family of blennies of which all members have a dorsal fin separated into three parts (hence the name); the first two are spinous.

The blenny resembles the goby, with one difference; the goby has fused pelvic fins that form a disc-shaped sucker. This sucker is functionally analogous to the dorsal fin sucker of the remoras. Another difference is that the  goby  has the habit of digging out his burrow and sifting sand, which the blenny' has not. 

Left: Tompot Blenny. Picture taken by Alex Tattersall (2007). In the UK, swanage pier dorset  is a favorite spot to meet the Tompot blennies. This blenny can get around 25 cm long.

 Anatomy    Combtooth blennies  have blunt heads and large eyes, with large continuous dorsal fins, which may have three to 17 spines.  The frontal part of the dorsal fin is often higher than the back part.  Their  name comes from  the comb-like teeth lining of  their jaws. Males and females are quite different, with the male being much more colourful particularly whilst breeding.  The swim bladder is usually absent in adults which will make them sink to the bottom. The bodies are compressed, elongated  and scaleless.  Most species  have two rays just anterior to their enlarged pectorals inserted near  the throath, and  a pair of branched tentacles above the eyes called cirri.  The  often branched tentacles  can vary widely in form and size dependent on the species.  Cirri could be  are an additional sensing organ that helps the blenny to read the current and know which way the food will be coming from, as well as to help them to anticipate the approach of predators. They could also function to impress its enemies or distract its prey.  The blennies eyes can function independently, giving them that goggle-eyed look that enables them to look in two directions at the same time, keeping careful track of both prey and predators.  

Pictures Their big eyes, colourful faces  and bizarre horn-like structures on their tiny heads make the blennies a favorite target for underwater macro photographers.  If… they are lucky to get a good  close shot of them, in particular of the head. Although I am not a blenny expert, I find the  best blenny shots those where the photographer  has succeeded to capture the blennies head with all its fine features and colours, in particular its eyes, crisp and sharp. Best opportunity is when the blenny is lying still, for example on a rock or peeping out of a tube or bottle against a neutral background. It is advised to bring the camera down to the level of the eyes of the blenny, and then patiently wait  for the moment when the blennny will look at you*. Macro should  be your first option, but if the blenny is not too small, a picture taken with a fish eye lense and mini dome  at close distance will probably also look nice. Good contrast is essential.  Using macro there are globally two ways to create a interesting contrast between your blenny and the background. One is using a narrow aperture and high shutter speed, which will create an almost black background. The other is a wide aperture (with high shutter speed), which will drastically reduce the depth of field and make the background blur (also called 'bokeh'). It will also make focusing a lot more difficult. To get at least one  sharp shot of your blenny, 'focus bracketing' is a handy method. Once the focus is set on your camera, rock slightly a little back and forth to achieve the sharpest focus while you keep on shooting. A wide aperture goes with the lowest intensity  of your strobes.

Behavior and habitat Combtooth blennies are found in tropical and subtropical waters in the Atlantic, Pacific and Indian Oceans; some species are also found in brackish  environments and in tide pools. They often spend their entire life cycle on one general location. For some species small crstiaceans, mollusks, and other sessile invertebras are the primary food items but others may eatalgae or plankton. Combtooth blennies spend much of their time on or near the bottom. They may inhabit the rocky crevices of reefs, burrows in sandy or muddy substrates, or even empty shells. Generally found in shallow waters, some combtooth blennies are capable of leaving the water for short periods during low tide, aided by their large pectoral fins to crawl around.  Blennies  have an undulating swimming style and strong teeth. Females lay eggs in shells or under rock ledges; males guard the nest of eggs until hatching. Most blennies  are voracious, mutually agonistical and curious.  If you watch long enough, you will often see a blenny dart out of its hole and grab a meal out of the water column. Often the blenny wil lie on a rock or sandy bottom, but some prefer  little crevices,  and even empty cans, bottles or  tubes to hide in.

Some species of combtooth blennies Some better  known combtooth blennies are (genus in Italics): the Molly Miller (Scartella christata), Tompot Blenny (Parablennius gattorugine: see picture above), the Butterfly Blenny (Blennius) with a big blueish-black spot on the frontal part of the dorsal fin,  the Adriatic Blenny (Microlippophrys adriaticus, no cirri) and the Blackhead Blenny (Microlippophrys nigriceps) from  the Mediterranean.  The Horned Blenny (Parablennius tentacularis)  is a  larger species often found in the Mediterranean (see frontpage for an example).

A particularly interesting group are the rockskippers (Salarius fasciatus). They are amphibious blennies, living in the surf and splash zone of rocky coasts. With twisting, jumping movements, they propel themselves over coastal rocky surfaces. These blenny species constitute a parallel evolutionary development to the mudskippers, amphibious gobies living in the mud out of the water. Similar ecological conditions have brought about similar adaptations.  Then we have the beautifully coloured Peacock Blenny (Salaria pavo)  and the False cleaner fish (Aspidontis taeniatus).  These  blennies have fang-like teeth with venom glands at their bases and are noted for their clever mimicry of cleaner  wrasses  Labroides dimidiatus.

Other families Scaled blennies belong to the large family of Clinidae that inhabit temperate oceans primarily south of the Equator. Dazzling and varied colors and markings differentiate the species. The largest clinid, one of the many pointy-headed blennies, is the 24-in (61 cm) giant kelpfish (Heterostichus rostratus), which inhabits the Pacific shoreline from British Columbia to Southern California. The 8-in (20-cm), blunt-headed, hairy blenny (Labrisomus nuchipinnis) belongs to the family of  Labrisomidae and lives in the tropical waters off both Atlantic coastlines. Another family is that of the Tripterygiidae or threefin blennies. This family contains some of the  smallest blennies —the female of the species  Tripterygion nanus found in the Marshall Islands, is fully grown at less than 0.75 in (1.9 cm) in length. Tripterygion tripteronotus (Black faced blenny, steep forehead, breeding males with red body up to 8 cm) is found in the Mediterranean. The Secretary and Spinyhead Blennies are tube blennies from the family of Chaenopsidae. Tube blenny lives in the vacated tubes of Calcareous Tube Worms and seem to prefer locations in plenty of light at the top of coral heads. At no more than two inches in length they are very hard to see and even harder to tell apart.The pike blenny (Chaenopsis ocellata) is a tube-dwelling species found in Florida. Male pike blennies jealously defend their territories from other intruding males by aggressively displaying a stiffly raised dorsal fin and a widely gaping mouth. Two males may literally face off, gaping mouths touching, until one snaps its mouth shut on the other. These blennies will often  create great photo opportunities. 

Source and links




Blennies - Species, Found, Fish, and Teeth - JRank Articles http://science.jrank.org/pages/960/Blennies.html#ixzz4lE5YqF4Y