Crustaceans

As you would expect there are many types of crustaceans living in our waters and along the shore line, so we will restrict ourselves here to the more unusual (or amusing) species.

The common feature of crustaceans is that they have an external skeleton (exoskeleton) which means that they have to moult in order to grow, leaving them temporarily vulnerable. Typically they have 10 legs, the front pair being adapted into claws or pincers.

Arrow crab

These funny-looking bright red, orange and yellow pointy-headed creatures are abundant in our waters and although tiny compared to humans they are quite fearless. They move quickly on their 8 legs, resembling a daddy-long-legs. If you get too close they will adopt an aggressive stance, waving their pincers at you. Towards other marine creatures, even their own kind, they are similarly aggressive and territorial to the extent that it is known amongst aquarium owners that you can’t keep more than one per aquarium. They feed on small creatures such as worms. In Tenerife they are frequently found alongside pink anemones.

Canary Island lobster
This small red lobster is native to the Canary Islands where it is quite common, especially in overhead environments with rocky or rocky-sandy bottoms.

Painted shiny lobster
This very decorative lobster is again common in our waters although on the critically endangered list. Its spotted back appears decorated with tiny pearls whilst its blue tail looks more fitting for a bird than a lobster!

Rock lobster
A fellow member of the critically endangered club, this brown lobster with tiny red dots and slashes of red visible at the joints of its skeleton favours rocky bottoms in sheltered spots such as caves and crevices.

Eels

There are several species of eel living in the waters around Tenerife. Those that we see most frequently are 3 types of moray eel (dotted, dark and tiger) plus garden conger eels.
 

Moray eels

Moray eels love the rocky habitats found in Canarian waters. The numerous crevices are ideal for their sedentary habits, although they do venture out at night to feed. Their diet is comprised of fish and cephalopods (octopus, cuttlefish and squid). Typically they grow to just under a metre in length. They have thick scale-less skin covered with protective mucus. The eyes are tiny, resulting in poor vision; they depend on their keen sense of smell for hunting. Even when stationary in their lairs during the daytime, the mouth is kept open, moving from side to side to help water circulate through the gills. So it may seem that you are being threatened by a wide open jaw full of long sharp teeth when, actually, it’s just breathing!

The dotted moray has a dark spotted (no!) body and is a species found only in the Azores, Madeira and Canary Islands. Dark morays are most commonly seen here and are a plain dark brown. Tiger morays have a longer more pointed snout than the other species but are most noted for their skin colouring which is not striped as its name would suggest, but spotted like a leopard. You just have to wonder whether something was lost in translation somewhere along the line…

Each of these species has a symbiotic relationship with lady scarlet shrimp, which clean the teeth of the eel whilst benefitting from the ‘ready meal’ that this represents.

For a dive with guaranteed sightings of moray eels, ask for Palm Mar Cave or Roncadores del Faro, though these creatures can be found at lots of our sites.

Garden conger eels

These form colonies in areas of flat sand to produce an amusing swaying garden of eels half buried in the sand and half exposed to catch plankton. From a distance you can observe them but if you go closer than about 2 metres they disappear into the sand like some synchronised disappearing act. Found at many of our sites including our local beach, Las Vistas.

Fishes

Roncador grunt fish
The name roncador means ‘snorer’ in Spanish, as these fish make a snoring or grunting sound as they are pulled from the water by fishermen. These silver-yellow fish grow to around 20cm and in themselves do not appear remarkable but they shoal in quite large groups and the sight of a shoal is mesmerising.

Typically they will ignore the diver, just responding to perceived threats in the water by suddenly all changing direction. But if a diver approaches the middle of the shoal it will part and then come back together as soon as the diver moves on. It is possible to take some dramatic photos in this way. We have several sites off the South West coast of Tenerife where we just know we are going to find shoals of roncadores as they are highly territorial, occupying in the same spot indefinitely, Palm Mar and El Faro being our favourite two. Curiously roncadores are abundant in 6 out of the 7 Canary Islands, but are not found in El Hierro.

Barracuda

It is usual that wherever we find a shoal of roncadores there will be a small group of silvery juvenile barracuda circling overhead looking for an opportunity to pick off a stray one for a snack.

This long, sleek and slender mean-looking creature is known to be a fierce predator, with its strong jaws and sudden speed, but divers have no need to be concerned as they are not known to attack humans. It’s the roncadores that need to look out!

Although they can grow to a length of 150cm, the juveniles that we see most regularly are around 60cm. Adults are more likely to be found in places with current, whilst the juveniles favour calmer waters.

Parrot fish
The parrot fish is so common in the Canaries that if we had a national fish then this should be it!

The female is unmissable with its bright orangey red colouring with patches of yellow and grey and of course the characteristic teeth, whereas the male is a much plainer grey with a black mark behind each gill. The typical size of an adult around Tenerife would be about 30cm although the male is always larger than the female. The teeth are important for dealing with its diet of small invertebrates.

Trumpetfish
The trumpetfish is unmistakeable with its elongated body topped with a long snout with an almost smiling mouth. A black spot is strategically situated either side of the body just before the tail so that it looks like another pair of eyes: hmmm, is that intended to confuse us about which end is the front?

They appear calm and benign, even friendly towards other fish unless, that is, you happen to be one of the small fish they feed on by suddenly sucking them in.

They can be seen at any of our sites but are most abundant at the wreck of El Condesito, where you will see specimens of up to 80cm in length. Individuals are sometimes seen swimming alongside a grouper, behaviour thought to both offer protection against predators and assistance in attacking prey.

Grouper
Grouper are found around the world, most especially in Florida. The species we see in Tenerife is the dusky grouper.

These chilled-out gentle giants are one of the favourites of our divers. They have stout bodies, brown with white markings, and a large down-turned mouth with fat lips. Not built for speed, they lie in wait for passing prey and therefore prefer sites with current. They have strong jaws which can crush their prey though the dusky grouper also has many small teeth, so a varied diet is no problem. They can grow to 1.5m, but it is more common to see them up to 1m. They are sequentially hermaphrodite which means that they start life as a female, in this case for approximately the first 8 years of life, then turn into a male.

Our favourite site for groupers is Barranco del Agua. As this is a 30m dive with current, this is only for experienced divers with the Advanced qualification or above.

Octopus and Cuttlefish

Along with squid these creatures are members of the species Cephalopod but, unlike squid which are highly pelagic, we frequently see octopus and cuttlefish, and we love them!

What’s wonderful about the octopus is that they are so curious, although a bit shy. But if you approach carefully so as not to scare them and tap gently on the rock you can tempt them to investigate with a tentacle or two – you will find them surprisingly strong! It’s worth keeping a lookout for cracks in the rock filled with small pebbles – this can be an indication of an octopus that has backed into an opening then pulled in pebbles after itself to complete the hideout. Take out one or two of those pebbles and you will likely see a suckered tentacle or arm.

What we also love about both the octopus and cuttlefish is the rapid colour change that they can perform in order to camouflage themselves against their background or to communicate with each other for mating purposes, for example. It is quite common to see this colour change occur as pairs of cuttlefish are swimming along; as the seabed beneath them changes from rock to sand to grass, so too does their colouring.

These Cephalopods have no protective shell; their head has 5 pairs of multi-purpose appendages around the mouth (the word Cephalopod is Greek for head-feet). One is a pair of tentacles that can extend rapidly in length and are important for catching prey. The others are pairs of arms and are used for holding and manipulating the prey. They are widely regarded as the most intelligent of the invertebrates and certainly have the largest brain:body ratio.

Most of the octopus we see are of the common brown variety although we are sometimes treated to the white spotted octopus, which is bright orange with, yes you got it, white spots. And the cuttlefish variety that we see is the African cuttlefish. Rather sadly, the female octopus stops feeding after spawning and dies after the eggs hatch. Nature can be so harsh! Cephalopods are not long-lived creatures, growing and maturing quickly and dying within 1-2 years. Local predators include groupers, pink dentex, dolphins and whales.

Rays and sharks

Rays and Sharks belong to the same group of marine creatures as each other: cartilaginous fish. The common characteristics are that they don’t have internal bones, but instead have a skeleton made of cartilage. They also generally have a thick skin without scales. And they give birth to live young, as the egg hatches inside the mother; it is possible to recognise when a shark or ray is pregnant.

Do we have sharks in Tenerife?
This is a really common question in our shop, and interestingly what people want to hear is split fairly evenly between those who really don’t want to encounter a shark and those who would love to. Well, Tenerife is surrounded by the Atlantic Ocean so of course we have sharks in our waters. However most sharks favour depths of 50 to 1000 metres, so we do not normally see them on recreational dives. So the answer is yes, but it might as well be no!

Angel sharks
A notable exception is the angel shark which, due to excessive hunting in the past, is now on the critically endangered list. We would expect to see these in fairly shallow water several times per week during the mating season, i.e. Spring, though they are also seen in Winter and sometimes Autumn. They remain here for the birth of the young so that we also get to see baby angel sharks in the Spring.

The angel shark has a flattened body, much like a ray, and grows up to 1.5 metres in length. To feed, it buries itself in the sand waiting for passing prey of fish, crustaceans and molluscs. It is not at all interested in humans but can be provoked into threatening behaviour, circling and even biting if someone has been really annoying, such as waking it by shaking its tail. You have been warned!

Obviously stingrays are thus named for the well known sting that they all have near the base of their tail which is for the purpose of defending itself against predators. We know of no occasion when a ray has shown aggressive behaviour towards humans.

Stingrays have similar body shapes to each other but the common stingray is the smallest and lightest in colour (sometimes called the yellow stingray).

The round stingray is dark in colour and can grow to over 1 metre from wingtip to wingtip. They are often seen in groups and can be found in caves and overhangs.

The roughtail stingray is not so frequent but is easily identified by ummm, you guessed it, its rough tail, which can grow up to 2 metres long.

The eagle ray has a similar body shape to the stingray but has a distinctive domed head. It can be easier to spot due to the fact that it does not spend so much time buried just under the surface of the sand but will be seen swimming freely.

The butterfly ray is fantastically well camouflaged against sand, having a mottled yellow colouring. It is triangular in shape, measuring up to 1.5 metres across, with a tiny tail with a sting. A pat on the back is due if you spot one of these beautiful creatures. The marbled electric ray has a round brown coloured body with light brown spots. It is the smallest of our rays, at up to 60 cm across. So named because it can deliver an electric shock, for defence or to stun its prey, it should not be approached too closely.

Did you know...
... that the local name for stingray is Chucho. Those of you old enough to have enjoyed a certain British TV puppet show in the 60’s may now be able to make the connection between the original name of our dive centre, Aqua-Marina, and the name of our boat, Chucho!

Sea Urchins: Vermin or victim?

The vermin argument:

Here in Tenerife some of our underwater volcanic rock surfaces have been colonised by black long-spined sea urchins which are believed to have originated from the Caribbean and inadvertently been transported here in trading vessels of the 19th century. They drastically alter the landscape that they inhabit by feeding on the algae that grows on the rocks, leaving the rocks scraped bare and depriving other species of both food and habitat. As they are not indigenous it is argued that they upset the natural balance and that their success is detrimental to native species.

An experiment at one of our dive sites, El Puertito, does seem to confirm this. For several years now this site has been cleared of sea urchins by one of the local dive centres (Ocean Dreams Factory). The University of La Laguna has been monitoring the resulting increase in both flora and fauna which indicates that in the absence of sea urchins, other species do indeed thrive.

This site is in fact now one of the most popular dive sites here as it is home to several green turtles, which may be due to the fact that they are mostly herbivores and their diet includes algae (though this may also be due to some surreptitious feeding by divers!)

The victim argument:

Sea urchins just get bad press because divers don’t like the nasty sting their spines can deliver. In fact they have every right to be here and have to take their chances with a number of predators, most notably starfish. The sight of a starfish attacking a sea urchin is something to watch: the starfish swings into action with its arms going in all directions while the sea urchin tries to make a run for it, usually unsuccessfully, though his close neighbours all make a getaway – not much solidarity there! If there are too many of them in places maybe it’s because the fishermen are catching too many of their predators such as the spotted burrfish – so it’s not the sea urchins’ fault, it’s the fishermen!

In some countries they are considered a delicacy on the seafood menu of restaurants, but for some reason they are not found on menus here. If we all just enjoyed eating them their numbers would be limited and our attitudes towards them would be very different.

Finally, they are actually rather splendid to view up close. An iridescent blue shines out from between the spines contrasting beautifully with the shiny black of the spines. Frequently tiny damsel fish of the same colours are darting in and out of the spine forest presumably enjoying the protection it affords. Symbiosis in action!

So what do you think? Vermin, or victims of bad press?

Some facts about Sea Urchins

• Sea urchins are found all over the globe in depths from 1 to 5000 metres. There are around 800 different species, some of which date back 450 million years.
• They are echinoids, which means that they have a skeleton composed of calcitic plates, usually bound together to form a solid structure called a test. This is the shell that can be frequently found in seaside gift shops.
• Their mouth is on the underside and they have teeth, so don’t get your fingers too close!
• They have tube feet with a suction disc at the end. These are mostly used for hanging on to surfaces, whilst the spines are used for motion. The tube feet also have an important role in feeding and respiration.
• They reproduce by releasing eggs and sperm into the water. It is very difficult to tell the difference between males and females.
• The young start out as larvae, feeding on microscopic plankton. After several weeks they undergo a metamorphosis into the adult form.
• They may live for 15 years or more.
• They can be eaten raw and are considered a great delicacy, particularly in Italy. The edible part is the organ that produces the eggs: it has a salty taste and light, soft and almost frothy consistency.

Starfish

Starfish are part of the same family as sea urchins, ie echinoderms, the name being derived from the Latin words for skin and spines. Usually they have 5 arms radiating from a central disc though there are species, also found here, with many arms.

For something that looks so pretty and inoffensive they are remarkably voracious feeders and highly talented at self preservation and recovery from attack.

Did you know...
...that a starfish can regenerate into its usual 5-armed shape from a single arm attached to the central disc?!

If you see a starfish with irregular arm lengths then it is in the process of regeneration. They can use this same system for reproduction – they just split into two and regenerate, although they also reproduce sexually.

For movement they depend on a water vascular system using many tube feet on the underside of the arms. There is a small eye on the end of each arm though sight is poor, distinguishing only light and dark. This is sufficient however to detect movement. The rough surface of the starfish prevents parasites from encrusting the body and the often bright colour is a deterrent to predators. They are able to feed on creatures larger than themselves because they have two stomachs, one of which can be expelled from the body and wrapped around the prey, digesting it with gastric juices before ingesting it. They can use their water vascular system to force open molluscs such as clams, insert their stomach and digest the clam in situ.

Their diet is largely made up of crustaceans and molluscs although they will feed on any animal, dead or alive, and they appear to love sea urchins.

Turtles

Turtles are reptiles that have been around for over 200 million years.

Of the 7 species of turtle found around the world, 2 are quite common in Tenerife waters: the green turtle and the loggerhead turtle. Sadly there are no signs that they breed in the Canary Islands so those that we see must be migrating to other shores for breeding.

We most regularly encounter turtles at the site called El Puertito (see the section on Sea urchins for more information on this), but they can be seen at other sites on random occasions. At El Puertito they are used to seeing divers and exhibit very friendly behaviour, sometimes acting as though they think they are part of your group, for example if we kneel in a circle to observe them, they might take their place in the circle.

A number of times we have found a turtle struggling at the surface after being caught up in fishing line or other rubbish when, of course, we are only too pleased to intervene to save them. But otherwise it is important not to touch and certainly not to hang on to them as this could prevent them from surfacing to breath. Also the beak, which is made of horn, can deliver a nasty nip!

Green Turtles

Although once common, green turtles are now an endangered species due to extensive hunting in the past which reached a peak with the popularity of turtle soup early in the 20th century. Happily, conservation efforts have resulted in a good recovery and there are some large populations in Costa Rica, Ascension Island, West Africa, Malaysia and Australia.

Young green turtles eat small marine creatures such as shrimp and jellyfish plus floating insects, sea grass and algae. As they mature they shift to a largely herbivore diet of just sea grass and algae, though some populations continue to feed on marine animals too. They are the second largest of the 7 species of turtles (after the leatherback) growing up to 1.5m in length and weighing in at up to 200kg.

Loggerhead Turtles

The name of this turtle is a result of its large head which in turn is due to its strong jaw muscles and large beak needed to crush crustaceans, its preferred diet. Unfortunately for the loggerhead it also enjoys jellyfish which is what plastic bags floating in the sea also look like.

Ingested plastic can be fatal, so we should all try to be careful to avoid littering the sea. Like the green turtle, the loggerhead is also endangered, threatened by tourism development at its nesting beaches and by bycatch in fishing, especially shrimp trawls and long lines set for tuna and swordfish.

Whales and dolphins

Whales
Although Tenerife is quite famously home to many resident pods of short-finned pilot whales, we are unfortunately not allowed to dive in the area where they are found, which is protected by local laws. If you wish to see these creatures then it will have to be from one of the many excellent licenced excursion boats – an excursion that we would recommend.

 

As it happens the pilot whales favour depths that far exceed recreational dive limits, as their favourite prey is giant squid. Also they blow bubbles as part of their communication repertoire, thought to signal aggressive or warning behaviour. They might not take too kindly to having a group of divers blowing bubbles at them! So maybe it’s for the best that we stick to the excursion. Most of the pilot whales we see around Tenerife are similar in size to dolphins, ie 2-3 metres.

Dolphins

Dophins are much more unpredictable in their whereabouts and we see pods of them on on the surface on a fairly regular basis but rarely whilst diving. Sometimes they are playful, breaching in the wake of the boat, for example, but sometimes they are just not feeling sociable and disappear as soon as we spot them. The species we see most regularly are the common and bottlenose, but there is also a small resident pod of Risso’s dolphins here which we were lucky enough to spot in April 2009 (see our Diving News).

The bottlenose seen around Tenerife usually grows to 2-3 metres, is grey in colour and has the distinctive snout so familiar to us all. It has a more flexible neck than other species as 5 of its 7 vertebrae are not fused together as in other species. (You can see that our picture of the Risso dolphin shows a much straighter-backed profile than the typical picture of a common dolphin). Its diet is a mix of fish, eels, squid and shrimp, which it swallows whole. No messing about! Risso´s dolphins are normally grey/brown as juveniles, acquiring more white patches as they mature. The tail splashing and waving that one dolphin was displaying when we spotted a pod is typical for this species.