Receding waters at low tide reveal sea life in the lee of onshore reefs and in shallow rock pools. Snorkeling along reefs in even shallow water reveals a dazzling display, and rock pools too provide insights into subaquatic worlds within worlds.
Following on from last week’s post featuring Sodwana Bay on the Maputaland coast, all photos in this post were taken at the rock pools off Jesser Point at the southern end of Sodwana Bay.
A view across Sodwana Bay from the rock pools off Jesser Point. Snorkelers and anglers stay close in near the rocks to stay out of the way of boats that launch parallel to the rock pools, which are exposed at low tide when this photo was taken
Although I enjoy snorkeling in the warm shallow waters at Jesser Point, when conditions are rough and underwater visibility is restricted another option is to amble along the edges of rock pools at low tide.
Visitors to the rock pools may become acquainted not only with the lifeforms clinging to the rocks and with some of the underwater residents, but also with other visitors to the rocky shores such as gulls and other birds.
A Greyheaded Gull with feathers ruffled by the wind, visits the tidal pools at Sodwana Bay
Instead of watching the impressive waves and the distant horizon, when walking round the rock pools I watch my step. The rocks are encrusted with Volcano Barnacles – the name no doubt reflecting the cone shape of these small crustaceans
Barnacles are uncomfortably sharp to walk on, and so it is sensible to wear appropriate non-slip soft-soled shoes when walking around the tidal rock pools. Although the barnacles may appear to be dead exoskeletons, in fact they are very much alive.
Adult Volcano Barnacles are adapted to being encased in their shells that are permanently attached to the rocks; they may be exposed above the water at low tide and most are completely submerged at high tide. When exposed to the air they withdraw completely into their shells and by closing small plates at the opening of their shells they seal themselves in. When they are under water, these remarkable creatures open these plates so that they can extend their feathery modified legs through the apex of the shell to comb the water for suspended food particles that they retrieve to eat.
Although when walking slowly I saw much of interest in the rock pools, I found that by picking a pool and waiting quietly next to it I was able to watch small inhabitants emerge from hiding places to go about their daily tasks. Common among the small fish in the pools are blennies and rockhoppers.
I think that this little fish in a shallow rock pool is a Horned Rockskipper
Waiting and watching allows one to see how animals move around as they seek or catch food, and perhaps one may even see unexpected interactions. I am aware that for many people exploring rock pools means prodding, poking, turning things over, picking creatures up or even catching them and placing them in containers so they can see them better or photograph them. I prefer less invasive forms of observation. Not only is there less potential to do actual harm, but one is able to observe natural behaviour rather than frightening creatures into hiding or stressing individuals that are handled or captured.
In general, codes of practice advise that visitors exploring rock pools should avoid treading on things that can be injured or damaged and recommend that people should not walk in or plunge into the small isolated rock pools. Creatures or plants that adhere to rocks or any other surfaces should not be removed. For instance, starfish (or seastars) cling to rock surfaces using tiny suction feet, so it is sobering to note that picking up a starfish can rip these tiny suction cups right off.
Although it is preferable not to touch anything, if one insists, then do that with wet hands/fingers and do it gently. But even so, touching is best avoided. For example, touching creatures like anemones can cause them to release their defensive chemicals, which become so depleted that they may not be able to defend themselves from natural foes or capture prey.
If rocks are turned over this must be done carefully and a removed rock should be replaced in exactly the same place and orientation it was originally. Some creatures routinely return to precisely the same spot and turning over a rock can destroy habitat for small creatures and disrupt shelter, breeding, brooding eggs or young, and disturb feeding. If one insists on removing a creature from the water then it should be returned to the exact same spot as soon as possible.
I watched this large crab apparently being observed by two rockskippers. I am not certain, but I think that the crab might be a xanthid crab, and if so its main prey animals are molluscs. With their powerful nippers they are able to crush the shells of many species of mollusc
Besides those who obtain subsistence foods from tidal pools, recreational fishing takes its toll on some forms of life in rock pools – for example some rock pool inhabitants are collected and used for bait. And also there are shell collectors who remove live shells and other specimens from tidal pools as well as from deeper waters. Most of the shells and all of the dehydrated creatures that are sold in beach and curio shops were taken alive from the sea.
Sadly, the removal of species and shells for the aquarium trade threatens many types of reef fish, corals and other animals, and entails a high mortality rate.
Besides these forms of utilization, visitors exploring the rock pools, especially in areas visited by lots of people and where curious visitors indulge in invasive practices, are also a threat to marine life. For more see here.
Submerged in tidal pools at Sodwana Bay are colonies of anemone-like zoanthids – well I think these are zoanthids rather than honeycomb coral. Can anyone advise?
This photo of fish in shallow water is confusing – the dark fish shapes are in fact shadows of the mostly silver fish visible at the top left-hand side of the photograph
Scoured by sand and water, these smooth pebbles and fragments of shells dappled by light filtering through clear shallow water form a pleasing natural collage of colour and texture
Submerged seaweed is fractured by ripples in the water that refract light to make a geometric abstract reminiscent of coloured glass
Like polished metal, these organisms cover submerged rocks. I am not sure what they are and wonder if anyone can identify them?
Perhaps this slightly longer shot conveys how shallow and small some of the pools are
Looking from the rock pools towards the breakers of the open sea
I recall how on one visit when a friend and I were engrossed in watching minute life forms in the pools, people on the beach struggled to get our attention as they shouted to tell us to look up beyond the breakers where three whales were gently floating and blowing. The contrast in size of the spectacular whales we were ignoring compared to the tiny creatures we were focussing on made people laugh at us. I did not have my camera with me, but you get the idea I am sure.
The tide is starting to come in and fill the pools. Time to depart to drier ground
While I was rock-pooling, scuba diving not far away out at sea, my husband took this photo of fish and coral at a very shallow reef. Many similar fish can also be seen by snorkelers in channels close to the shore
Sources:
Branch, G M, Griffiths, C L, Branch ML & Beckley L E. 2005. Two Oceans a Guide to the Marine Life of Southern Africa. Cape Town: David Phillip; Goldberg, Jenifer. 2005. Aliwal Shoal: Dive Guide. Durban: Jenifer Goldberg in association with The Green Trust (a partnership between WWF and Nedbank); Hilltromper. 2013. 10 Tips for Happy Tidepooling. http://hilltromper.com/article/10-tips-happy-tidepooling; Kennedy, Jennifer. 2018. Intertidal Zone Characteristics, Challenges, and Creatures. ThoughtCo. https://www.thoughtco.com/what-is-the-intertidal-zone-2291772
Posted by Carol
October 23, 2019 at 12:39 am
I’ve been out in the desert for 3 weeks and trying desperately to catch up. It’s almost embarrassing to admit how many pictures I took and what fantastic fun we had. Your post was a refreshing pause from the parched earth.
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November 7, 2019 at 7:38 pm
I have also been away. Glad you had a great time away in the desert and I look forward to catching up with your photos.
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October 15, 2019 at 7:03 pm
Thanks very much 🙂
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October 15, 2019 at 12:42 pm
It was an Interesting read about intertidal animals.Nice pictures!
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October 8, 2019 at 6:29 am
Tide pools are so much fun to explore. All kinds of activity going on which is easy to miss. I particularly like your almost abstract photos, whether from the light or shapes within the pools. Your polished metal organisms might be some kind of zoanthid, though I’d hestitate to try and say which one.
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October 8, 2019 at 8:37 pm
Thanks Graham, yes I also thought it most likely to be some kind of zoanthid, but no idea which. You are most fortunate to live near a warm and snorkeler-friendly seaside with so much to see and explore.
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October 6, 2019 at 6:05 pm
I echo what has been mentioned by one of your readers – rock pools share so much in common regardless of where in the world we find them. There are many rockpools near us. They seem like miniature worlds and are so rewarding to watch quietly. Your gorgeous photos reflect all that beauty, Carol.
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October 6, 2019 at 8:03 pm
They definitely do seem like miniature worlds – it is hard to reconcile these small tranquil pools with them being submerged under often pounding surf for much of each day!
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October 6, 2019 at 7:12 am
Again you have opened up a new world for me. I must go down to the sea again …
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October 6, 2019 at 7:37 pm
Oh that poem – how it imprints itself! On a par with “What is this life, if full of care …”. Perhaps its easy to understand why!
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October 7, 2019 at 7:35 am
I had to look up the poem by William Henry Davies. Exceptional advice
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October 7, 2019 at 7:10 pm
I think so too. Both poems are unfashionable and some may say trite, but they do have a certain something 🙂
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October 5, 2019 at 3:31 pm
I really like rockpools, and you have a wonderful series of most interesting and beautiful life forms here Carol.
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October 5, 2019 at 7:15 pm
Thanks very much Pete. I don’t often take the camera to the beach because of the sand, gritty wind and the salt, but I am always glad when I do.
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October 4, 2019 at 2:46 pm
It’s remarkable how tidal pools there look much like their counterparts here on the Maine coast. Gulls and crabs and barnacles are all common here. We don’t have the coral in our cold waters, though. I’m rather jealous of that! 🙂
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October 5, 2019 at 7:13 pm
Given the huge temperature differences it is surprising there is so much in common!
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October 6, 2019 at 3:59 pm
I know, it’s crazy!
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October 4, 2019 at 12:56 pm
Rock pools are the best. Never know what u are going to see!!
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October 5, 2019 at 6:54 pm
So true – they are filled with enchantment and sometimes mystery 🙂
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October 4, 2019 at 7:58 am
Lovely! I’m off to Pondoland next week so will carefully explore those marvellous rock pools and perhaps a blog will follow…
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October 5, 2019 at 6:50 pm
Have a great time in Pondoland Nikki. I look forward to your blogging about it.
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October 4, 2019 at 4:32 am
You provide sage advice. As a landlubber, I used to be enchanted by rock pools on the few occasions we visited the South Coast during childhood holidays, It is still an alien, yet beautiful, world for me.
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October 5, 2019 at 6:40 pm
I also recall childhood holidays to the South Coast and spending many hours gazing into rock pools. The seaweed alone could be magical.
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October 4, 2019 at 1:57 am
Another exceptional post, Carol, both for its content and beautiful images!
I must admit that I know far too little of the intertidal ecosystem and I would love to know more. Perhaps that’s exactly why I find it so enthralling to explore the rock pools on the few occasions we are at destinations where these are accessible, all the while being careful not to disturb the inhabitants too much – it messes with mu photo opportunities! 😀
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October 5, 2019 at 6:38 pm
I too would like to know more about the fascinating intertidal ecosystems.
It is so true what you say about how being ‘invasive’ can mess with photo opportunities. I am sure you have had times when patient waiting has been voided by unaware visitors just wading in – figuratively or literally.
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October 6, 2019 at 2:34 am
That too does happen occasionally!
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October 6, 2019 at 7:32 pm
🙂
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October 3, 2019 at 8:34 pm
The world between land and sea is so mesmerizing, I can see why you were engrossed, not seeing the whales. Great, informative post, Carol, and per usual, terrific photos.
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October 3, 2019 at 8:39 pm
Thanks very much Eliza. Yes that kind of edge in the littoral zone is very special, and for us humans it can really feel … edgy 🙂
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October 3, 2019 at 8:29 pm
Watching and waiting at rockpools. Perfect words and photos, Carol. Evoked an instant sense of ‘relax’, ‘let go’, see what’s really happening in these miraculous small worlds.
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October 3, 2019 at 8:36 pm
Thanks Tish. I suppose that kind of watching gives us permission to let go and enter into another kind of dimension. It really is like another world.
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October 4, 2019 at 1:51 pm
A sort of eyes-wide-open meditation.
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October 5, 2019 at 6:54 pm
Absolutely 🙂
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October 3, 2019 at 8:15 pm
I think that observing rock pool life may have been one of the early experiences that got my children interested in the natural world. The variety of life to be witnessed, from slow starfish to gently swaying anemones, hermit crabs … and son and so on entranced them. And yes, the only things we picked up on the beach were obviously no-longer-living shells. And now they watch their own children’s wonder and engagement. Brilliant stuff.
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October 3, 2019 at 8:25 pm
It is interesting, Margaret, how rock pools draw us in and are so entrancing. So lovely that your children and their children too have been and continue to be so captivated. There is something about rock pools that can be simultaneously grounding and transporting.
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October 3, 2019 at 7:17 pm
How marvelous to see these sea treasures right at your feet, Carol. Fantastic images to accompany your interesting descriptions. There are some great tide pool areas on the California coast that are such fun to explore. Thank you for reminding me how special it is.
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October 3, 2019 at 7:58 pm
Thanks very much Jane. It is good to remember how small can be so beautiful and intriguing 🙂
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