Sea life: Blennies

More often than not, the horned blenny (Parablennius cornutus) will be seen in the attitude above – hiding (annoyingly) in a crevice or, as in this case, a vent on top of the superstructure of the wreck of the MV Aster.

Blenny hiding on the Aster
Blenny hiding on the Aster

On a dive on the Aster in mid February we spotted another specimen, lying on the deck towards the bow of the wreck. These fish are renowned for their skittishness, but this one was so relaxed that I had to check with Guido at SURG that I was in fact making the correct identification! Guido has written more than one volume on identifying marine life in the area and is working on a book project at the moment, so he’s the man to speak to.

Top view of loose-skin blenny, on the Aster
Top view of loose-skin blenny, on the Aster

Guido says that what has previously been thought to be a horned blenny (i.e. this fish) is actually something else. He says:

Instead, this species is Chaloderma capito, the loose-skin blenny. In many instances this is clearly visible, as especially around the head the skin has many folds. This is visible in your specimen as well.

Side view of loose-skin blenny on the Aster
Side view of loose-skin blenny on the Aster

In fact, horned blennies are really hard to find and see, and it turns out that several of the books on marine life in this area mistake the loose skinned blenny for the horned blenny. Guido sent me a picture of a real horned blenny, and instead of the fluffy tufts that this specimen has above its eyes, it has two very distinctive, long, pointy horns that give it its name.

Loose-skin blenny on the Aster
Loose-skin blenny on the Aster

Science in action! What would we do without SURG! I certainly wouldn’t know one tenth as much as I do about marine life in the Cape were it not for Guido and company’s frequent help with tricky questions of fish identification.

Sea life: White stumpnose

They’re hardly visible in the picture below, but there’s a school of tiny silvery fish swimming low over the sand. These are white stumpnose (Rhabdosargus globiceps), which spawn inshore in spring and summer. They grow up to 50 centimetres in length after about 21 years, and are found all around the South African coastline. In summer they come inshore, where they are exploited by anglers, but in winter they move offshore into water over 100 metres deep.

Juvenile white stumpnose on the sand at Long Beach
Juvenile white stumpnose on the sand at Long Beach

Juveniles feed first on zooplankton, then on algae, amphipods and isopods, and when their molars are big enough (at around 4 centimetres) they move on to molluscs, crab, shrimps and worms. The fish in these photos were each no more than about 5 centimetres long. Unlike Roman, stumpnose do not change sex as they mature.

White stumpnose juveniles at Long Beach
White stumpnose juveniles at Long Beach

I don’t think I’ve seen an adult white stumpnose in the wild. The closest I’ve gotten is to the red stumpnose on display in the Kelp Tank at the Two Oceans Aquarium. Which I suppose doesn’t count at all, since they’re a different kind of fish!

I’m grateful to Guido at SURG who helped me to identify these little fish. Here’s the same photo as above, but fixed with some image manipulation techniques to bring out the contrast more. Maybe it’ll help to spot the little fish!

White stumpnose (enhanced)
White stumpnose (enhanced)

Sea life: Flutemouth

In his post about Long Beach Tony has mentioned that it constantly serves up wonderful surprises in the form of creatures not usually seen elsewhere. Some of these are visitors who get washed into False Bay on eddies of the warm Agulhas current, and then end up behind the harbour wall through an accident of winds and current within the bay. In late January we were treated to two sightings (on the same dive) of some of these visitors.

Flutemouth at Long Beach
Flutemouth at Long Beach

Smooth flutemouth (Fistularia commersonii) are not usually seen further south than Mossel Bay. They can grow to 1.2 metres in length; since the ones we spotted were about 30 centimetres long, it’s safe to assume that they were juveniles. We saw them swimming in a loose group of 4-6, with grimly determined little faces. They are almost the same colour as the sand, so you have to look carefully in the picture above to spot them.

Flutemouth at Long Beach
Flutemouth at Long Beach

They feed on other fish – according to Coastal Fishes of Southern Africa their preferred prey includes moray eels (small ones, I guess!), snake eels, pilchards and damselfish. They stalk their prey, and when they are close enough draw their bodies back in an S shape to strike like a snake. They will sometimes use other herbivorous fish (such as parrotfish) as a stalking horse to approach its prey, swimming alongside the other fish in order to avoid spooking their target.

On the SURG website there are records of two other sightings of flutemouth in Cape waters (there have undoubtedly been others). There is another kind of flutemouth, the serrate flutemouth (Fistularia petimba), which is usually found in deeper water north of Walvis Bay. It is reddish brown on top, wheras the smooth flutemouth has an olive upper body (when fully grown) and blue lines or spots down the side of its body. I think these flutemouth are of the smooth variety – a blue line is visible running down the side of their bodies. Click the second picture to enlarge it.

This next image is the same as the one above, but with more contrast so you can see the colours of these little fish a bit better:

Flutemouth (enhanced)
Flutemouth (enhanced)

Sea life: Walking anemones

Walking anemone illuminated by Tony's strobe
Walking anemone illuminated by Tony's strobe

The walking anemone (or sock anemone, or hedgehog anemone – Preactis millardae) is endemic to Cape waters and I’ve only seen it on the Smitswinkel Bay wrecks so far. It has been seen as far east as Port Elizabeth.

Walking anemone on the SAS Good Hope
Walking anemone on the SAS Good Hope

It likes deeper water, 10-30 metres. Instead of being attached to a rock or the sand (sessile), these creatures walk about with a movement like a slinky or caterpillar.  Their favourite food is multicoloured sea fans, so instead of waiting for a snack to drift by (like most anemones do), walking anemones actually have to move about to find their next meal. If you look carefully you can see how the anemone in the picture above has eaten the red sea fan to its left down to the skeletal supports (like little twigs). They also like soft corals.

Multicoloured sea fans
Multicoloured sea fans

Their bodies can stretch out to resemble a sock, but in these pictures they are scrunched up. The mouth has red lines radiating outward from it. The first time I saw one of these I thought it was a grubby orange gas flame nudibranch, because I couldn’t see the mouth stripes. Revisiting that picture (below) in light of the new specimens I’ve seen since has confirmed that it was a walking anemone and not a nudibranch!

Walking anemone on the MV Rockeater
Walking anemone on the MV Rockeater

SURG has some information about walking anemones here and here.

Sea life: Horsefish

A pouty horsefish on the SAS Good Hope
A pouty horsefish on the SAS Good Hope

Tony and I have seen a horsefish at Long Beach on one occasion, languidly swimming near the sand in a fairly empty (at first glance) part of the beach. He was incredibly docile, and as we all gathered around him in awe, he merely flapped his pectoral fins at us gently. Unfortunately it was my third dive for the day and my camera battery had expired, so we had no photographic proof of this encounter.

Smooth horsefish at Tivoli Reef
Smooth horsefish at Tivoli Reef

Since then we’ve met horsefish on the SAS Good Hope in Smitswinkel Bay, and on Tivoli Reef, a newly discovered area east of Roman Rock lighthouse. These fish are often very calm and passive, which gives excellent opportunity to admire their very, very cute puckered up lips and steeply sloping foreheads. They are usually quite slow swimmers. When they extend their dorsal fins they’re quite impressive, and they can apparently grow to up to 75 centimetres in length. The ones I’ve seen were probably no more than 30 centimetres long.

Well camouflaged smooth horsefish at Tivoli Reef
Well camouflaged smooth horsefish at Tivoli Reef

There are two varieties found in Cape waters: the spine-nosed horsefish, and (we’ve only seen this one) the smooth horsefish (Congiopodus torvus). SURG has some horsefish information here and here.

Sea life: Worms

Worms may not seem to be a particulary alluring choice of topic to mull over, and I’m actually inclined to agree with you after listening to my sister (mother of an infant) recounting the tale of how a friend of a friend had to remove a roundworm from her toddler’s nose (DON’T ask)… But marine worms are somehow less repulsive than terrestrial ones, and certainly come in a huge variety of shapes and sizes. Fanworms are pretty, but all the rest have at least something interesting about them…

Most marine worms are segmented, from the phylum Annelida. The examples here, however, are not!

Peanut worm on the Clan Stuart
Peanut worm on the Clan Stuart

Peanut worms, which belong to the phulum Sipunculida, have a tubular portion called an introvert that can be squeezed out with muscular contractions. Very attractive. They are unsegmented and when threatened they can contract their bodies into the shape of a peanut by retracting the introvert.

Milky scaleworm at Long Beach
Milky scaleworm at Long Beach

I found this milky scaleworm at Long Beach, and thought it was a feather in the shallow water on the sand. When the feather ran away from me, my impression was corrected! These little worms often share burrows with sandprawns, which are quite copious at Long Beach. Milky scaleworms are Polychaetes, which implies that they have chitin protrusions (usually kind of furry) emanating from each of their body segments.

Underside of the milky scaleworm
Underside of the milky scaleworm

Glycerine worms live in the sand, and I sometimes see them moving vigorously. They are also Polychaetes. They have four sharp sets of jaws and is quite a vicious predator (as worms go), feeding on other worms and crustaceans.

Glycerine worm at Long Beach
Glycerine worm at Long Beach

Flatworms belong to the phylum Platyhelminthes. I was very excited to see my first carpet flatworm in April, but the sighting was immediately (minutes later) followed by several more, and again on subsequent dives over the next few weeks. These worms are often mistaken for nudibranchs, but they’re worms through and through. The knobs on its surface are for camouflage, and also to increase the worm’s surface area. This assists in respiration.

Carpet flatworm at Long Beach
Carpet flatworm at Long Beach
Head-on view of a carpet flatworm
Head-on view of a carpet flatworm

Hitch hikers

The idea for this post was prompted by a two recent dives. One we did at Partridge Point, where the life on the rocks is so prolific that in places it seemed to be stacked on top of itself for want of space. The other we did one evening at Long Beach, and on the way out at the end of the dive, in the first two metres of water off the beach, I spotted two tiny long-siphoned whelks, clearly juveniles. One was hitching a ride on the back of a hermit crab!

Baby long-siphoned whelk riding a hermit crab
Baby long-siphoned whelk riding a hermit crab

Returning the favour, here’s a close-up of part of the shell of a simply enormous long-siphoned whelk (probably over 30 centimetres long) at Partridge Point. He’s got a variety of creatures on his shell, most noticeably a bright red-chested sea cucumber!

Whelk with red chested sea cucumbers hitching a ride
Whelk with red chested sea cucumbers hitching a ride

Many of the brittle stars I’ve seen lately have been covered with very photogenic little crustaceans called ornate amphipods, looking a bit like wood lice in full party dress. They are common, but not often seen by divers as we tend to focus on the big stuff! They are scavengers and feed on whatever they can find as they travel over reefs (and, in this case, other marine life)!

Ornate amphipods riding on a brittle star
Ornate amphipods riding on a brittle star

Even though sea squirts don’t have thoughts or emotions as such, I was amused by this cluster of red bait that I saw at Long Beach. It’s been covered by another kind of colonial ascidian (the greyish blue mass with white siphons), leaving just the large siphons of the red bait visible.

Red bait under a colonial ascidian
Red bait under a colonial ascidian

Something similar has happened here:

Encrusted red bait
Encrusted red bait

Some of the hitch hikers we see aren’t entirely benign. I’ve already posted a picture of a puffadder shyshark with a copepod parasite sticking out of his gill covers – these parasites don’t cause the fish any noticeable discomfort, but they’re not without impact. Here’s another unfortunate shyshark we found at Long Beach early in February.

Shyshark with parasite in its gill cover
Shyshark with parasite in its gill cover

Fish lice tend to attach themselves just above the eye of fransmadam, hottentot and similar fish. The lice essentially drink the blood of their host fish – they’re horrible creatures and we’ve noticed that many of the fish affected by them tend to hang around divers and to swim very sluggishly. Guido of SURG has pulled off a louse before, from a very docile fish, and there was a big seeping hole in the fish’s head underneath where the louse was attached.

Fransmadam with fish louse at Fisherman's Beach
Fransmadam with fish louse at Fisherman's Beach

Tony and I have seen very small fish with lice attached, almost a quarter of their size, and fish with more than one fish louse in residence. Here’s a maasbanker, one of a school that followed us around for a couple of dives at Long Beach in March.

Juvenile maasbanker with fish louse
Juvenile maasbanker with fish louse

In the picture below, the fish second from left towards the top of the photo has a large louse on his head.

Hottentot at Sunny Cove
Hottentot at Sunny Cove

After all that depressing parasite stuff, here’s a picture I find absolutely hilarious. The starfish isn’t going anywhere fast, but looks as though he’s reclining in a plushy couch formed by his fellow marine creatures. He is begging to have a smile photoshopped on!

Happy starfish at Partridge Point
Happy starfish at Partridge Point

Magazine: African Diver

African Diver is a freely available South African diving magazine, that appears only in electronic format. You can subscribe to their newsletter which alerts you to new editions, which come out six times a year. The magazine has been running for about two and a half years.

African Diver issue 14
African Diver issue 14

The magazine covers a wide range of diving and ocean-related topics, from dive sites and dive travel, to conservation, safety (they have a close association with DAN), wrecks, photography and free diving. The focus is on diving in Africa. The photos are gorgeous and plentiful. Because it’s digital format, large photo spreads don’t cost the publishers anything extra, which makes for a fantastic full-screen experience.

That said, I don’t find the format of the magazine particularly user-friendly – you have to download a pdf file which can be up to 15MB in size, so it involves commitment – and I do struggle to commit to reading anything on a computer screen for a significant length of time (rich coming from a blogger who hopes you WILL commit to reading THIS on a computer screen!).

But the format enables the magazine to be free and it does mean you can change the font size to super ginormous if that’s what your eyes need. Also, you can zoom into those stunning photos to your heart’s content. There is also an option that enables you to read the magazine online, without downloading the whole thing.

There is an interesting blog on the African Diver site, that is updated more frequently than the magazine.

Latest issue (Issue 14)

Georgina Jones of SURG writes an article about local dive site Star Walls (in the Atlantic). There’s a final installment from a couple who drove cross-country from Betty’s Bay in the Western Cape to Japan, in order to highlight what humans are doing to our oceans. There’s an article on shark finning in Mozambique (by the same author who wrote an article on the identical topic for the latest issue of The Dive Site).

There’s a very interesting article about deep diving, and the independent attitude that is required by divers when they reach the Advanced qualification stage. The author, Debbie Smith, lists the aspects that an Advanced diver should be able to manage: their own kit, their buoyancy, tucking in their gear, getting down, safety stops, helping themselves on the boat, and so on. It’s a very salutary reminder that even though you can theoretically be qualified as an Advanced diver after doing only nine dives ever, there’s a lot more to it than that.

There’s a very inspiring article about disabled scuba divers, and a safety review from DAN of 2010.

Magazine: Divestyle

Divestyle January/February 2011
Divestyle January/February 2011

Until the advent of The Dive Site, there were two primary South African print edition diving magazines: Submerge, and Divestyle. We subscribe to both of these. Frankly, The Dive Site has set a new standard for diving magazines, but it’s early days yet and Submerge and Divestyle are well-established.

Of the two (Divestyle and Submerge), Divestyle has the most professional look, at least on the cover. Submerge looks a bit like an eighties throwback, a lot like the tacky photography magazines that rely on lurid fonts and neon colours on the cover to get attention.

To be honest, however, there’s not much to differentiate the two magazines. Sometimes they put out issues within weeks of each other, with identical topics for their cover stories. We’ve just received the latest Divestyle, though, so I can comment in detail on it.

The magazine is published by the husband and wife team who produced The Dive Spots of Southern Africa. Many of the articles in the magazine are written by one or both of them. Fiona McIntosh, author of the Atlas of Dive Sites of South Africa and Mozambique is also a regular (and much appreciated) contributor.

They do have a useful section near the front of the magazine where local dive centre owners and dive instructors can provide short updates on the current local dive conditions – this section was particularly interesting and active after the fire in Ponta do Ouro and has provided a good way to keep up to date with developments among the dive operators there.

I also enjoy the technical diving section (strangely enough, since I’m firmly in the recreational scuba camp!) for its contributions by greats such as Don Shirley, Peter Herbst and Nuno Gomes. The format here is that a question is posed, and several tech divers contribute their opinions. There is a regular column by a diving instructor, too, which provides interesting (and sometimes controversial) insights.

The dive travel aspect of the magazine is pretty good – we keep old issues of all our diving magazines for this very reason. Both local and international destinations are covered.

The photographs are generally of high quality, and there’s  a section where readers can send in their own photos for a bimonthly competition. I enjoy seeing what equipment others are using, and personally judging the results!

Tony enjoys the various bits and pieces of advertising leaflets that come with the magazine… He often wonders what sort of quality training a dive centre that offers a “buy one Open Water course, get one free” offer is willing to provide…

The Divestyle website is quite useful, with useful information on local and international travel destinations available free of charge. There are book and DVD reviews as well as a few dive gear and camera reviews too, but not as many as I’d expect. (The magazine has a regular section on cool new gadgets and toys for divers… Tony and I enjoy those pages particularly!)

The magazine comes out six times per year. There’s not much of a saving off the cover price for subscribing, and it doesn’t arrive earlier in my postbox than it does in the shops… But I do find it convenient to subscribe. You can get hold of it in local dive shops and (I think) at CNA and Exclusive Books.

Latest issue (January/February 2011)

This latest issue (cover pictured above) got up my nose because the editor commented that an article he’d published in the current issue concerning evolution didn’t sit well with his personal convictions. All well and good, but how does putting a bikini-clad woman on the cover sit with your convictions? It’s naive to think that there’s any deeper interpretation of the image that can be made, other than “sex sells”, and hypocritical to object to an article on evolution on religious grounds, but not to an almost naked covergirl! (Given my background, I know about this stuff… the religious side, not appearing almost naked on magazine covers, I mean… and can sympathise, but I can’t bear hypocrisy!)

There was also a vapid article about the broadnose sevengill cowsharks in False Bay. The image accompanying the piece could have been much improved (talk to Jacques, for example) and to say that the article said nothing useful would be quite complimentary. A local expert such as Georgina Jones, while acknowledging the shortcomings in our knowledge of these wonderful creatures, would have been able to provide a far more insightful and informative article.

That said (as I climb clumsily down off my high horse), I wouldn’t dissuade you from subscribing, and I will acknowledge that we did enjoy this issue about as much as we usually do!

Sea life: Nudibranchs

Gas Flame nudibranch on the SAS Pietermaritzburg
Gas Flame nudibranch on the SAS Pietermaritzburg

Nudibranchs are wildly colourful invertebrates that look like psychedelic underwater slugs. There are countless varieties but it takes a practiced eye to spot them. My excitement when I do find one is totally out of proportion, but I do love these little critters!

Gas Flame nudibranch on the SAS Pietermaritzburg
Gas Flame nudibranch on the SAS Pietermaritzburg

Nudibranch means “exposed (nudi) gills (branch)”, and on almost all varieties you can see little protrusions that are those very gills – looking like fronds. The visual extravagance of these creatures cannot be over-stressed… Their beauty is totally unncessary, and all the more delightful for that.

Gas Flame nudibranch on the SAS Pietermaritzburg
Gas Flame nudibranch on the SAS Pietermaritzburg

Their bright colours tend to warn predators that they aren’t tasty, and nudibranchs have some very ingenious defence mechanisms (thanks to the Two Oceans Aquarium for teaching me this!). They eat things that are unpalatable or indigestible to most other sea creatures, including sponges and hydroids with stinging cells. Some nudibranch species then retain the stinging cells in their bodies, piggybacking off their lunchtime snack’s defence tactics.

Crowned nudibranch
Crowned nudibranch on the wreck near the yellow buoy at Long Beach

We do see nudibranchs at Long Beach – I’ve seen three or four species there, most often the orange-clubbed nudibranch. These tend to be spotted feeding on kelp fronds. Other species can be seen on the rocky reef to the right of the pipeline, and in lesser-dived areas such as the wreck near the yellow buoy. A Frame is another good spot for finding them, particularly in the swim-through. Careful inspection will be rewarded. There are also several varieties unique to the Smitswinkel Bay wrecks – the mechanism of this differentiation astounds and fascinates me – but I haven’t as yet managed to spot any except for a gas flame nudibranch this past weekend on the MV Rockeater.

Gas Flame nudibranch on the SAS Pietermaritzburg
Gas Flame nudibranch on the SAS Pietermaritzburg

Another frequent sighting at Long Beach is the warty pleurobranch, a devastatingly cute and cuddly little slug. They seem to have such personality, with their little eye stalks and bulldozer front ends. They’re not colourful, but lots of fun to watch. We often swim over them in the beds of sea grass, and sometimes on the sand.

Warty pleurobranch
Warty pleurobranch at Long Beach

As a reference for identification you can go to Dennis King’s book – focused on the east and south coasts of Southern Africa, Georgina Jones’s book, or – the mother lode – Guido Zsilavecz’s book. Both of the latter two are concerned with the Cape Peninsula and False Bay. If you’re serious about these gorgeous creatures, I’d go for Guido’s book: Nudibranchs of the Cape Peninsula and False Bay.

Gas Flame nudibranch on the SAS Pietermaritzburg
Gas Flame nudibranch on the SAS Pietermaritzburg

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