TAKING A CLOSER LOOK: ROCK POOLS ON ABACO


Rock Pool, Abaco 2

TAKING A CLOSER LOOK: ROCK POOLS ON ABACO

Here’s a promising-looking rocky outcrop a short distance south of Crossing Rocks. The action of the sea over centuries has eroded and pitted it – ideal for the formation of pools in which marine life can thrive.Rock Pool, Abaco 1

Time to clamber up to see if the theory holds good… the prospects are encouraging. There are certainly plenty of sea urchins here.Rock Pool, Abaco 4

Let’s zoom in on the nearest pool. There are clearly 2 different-coloured sea urchins here, but I’m not sure if that’s an age thing or a species thing. Rock Pool, Abaco 6

Apart from the sea urchins, there are some shells and other things that need a closer look…Rock Pool, Abaco 5

At the bottom of these photos, you can see that a zebra-marked nerite is quite happy to share a hole with an urchin. There are two brownish accretions on or in the rock. My tentative suggestion is that these are the shells of some sort of worm, perhaps petaloconchus.

UPDATE Rick Guest helpfully comments “Yes, it’s quite the invertebrate hotel mostly due to the urchin’s talent for scouring out protective “rooms”. Of interest is the Magpie shell (Livona pica) in frames 4 and 5. The rather ubiquitous Livona’s very thick shell, (Up to 5″ diameter) and ability to withstand most attempts at removal by predators, including Homo sapiens, assures their continued presence on littoral shore lines. They are edible, but not particular tasty to my palet. All these “Condo” residents “party” at night and will even leave the rock in search of food and perhaps romance, so a flash pic of the condo at night would be an interesting contrast to a daylight shot”.ROCK POOLS, ABACO 11

In a snug little cave (top right) just above the water-level of the pool is a primitive-looking chiton, a species that has been around for millions of years. Below, there’s a clearer image of one from a different pool. These creatures always remind me of school projects on prehistoric trilobites.Rock Pool, Abaco 7Rock Pool, Abaco 10

The rough rocky surfaces close to the pool are covered in shells. The stripey nerites are small, the grey shells really are miniature.  They are mostly littorines/ periwinkles and perhaps ceriths, I think.Rock Pool, Abaco 9Rock Pool, Abaco 12

Close-up views of nerites showing their distinctive markings and spiralsRock Pool, Abaco 13Rock Pool, Abaco 14

BEACHCOMBING WITH KASIA: EXPLORING A ROCKY SHORE


Kasia’s back! She recently explored a rather unpromising-looking stretch of Abaco coastline, and it proved to be anything but… Kasia writes: The story goes: one day I took myself for a walk and a bit of beachcombing. I usually don’t bring my camera with me but luckily this time I did. This particular beach looks very barren but on close inspection and a patient eye there are some lovely treasures to be found. Here are some of the treasures I captured!

A tangle of 3 bleached trees, with their roots apparently intertwined

CHITONS

Great close-ups… are those eggs behind this first one? There’s a similar image in the Macmillan ‘Marine Life of the Caribbean’ but unfortunately neither the caption nor the text refers to them. ADDENDUM: Colin Redfern writes: The “eggs” behind the chiton are fecal pellets

NERITES (Nerita)

 

WEST INDIAN TOP-SHELLS (Cittarium Pica) 

In this image, several very small chitons can also be seen on the rock

It looks as if someone… or something… has been having a Nerite feast on the shore. A bird maybe?  I had taken the shells above and below to be another variety of Nerite, but as so often scientist and shell expert Colin Redfern has kindly corrected the error. He writes: “Very nice photos. The “nerite feast” is actually a pile of broken West Indian Top-shells (Cittarium pica). The photo immediately above shows a live group of the same species. This is what Bahamians call a whelk (or wilk), and in the lower photo they have been harvested, probably for a stew.

 ROCK POOL MISCELLANY

I am trying to ID a much as I can in this pool. All suggestions welcome via ‘Leave a Comment’. So far, the corals are Brain Coral and Pink Coral (I think) but I am going see what else can be given a name…

These are my favourite! :) Kasia

COMET SEA STAR (possibly juvenile, with 3 such short stubs?)

A SPONGE (?) OF SOME SORT (any help with ID appreciated…)

                RED ROCK URCHINS