Paul Naylor discovers a world of diversity in a small patch of seabed in the sheltered water of a Scottish sea loch
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Sea loch diversity on display
‘ On the Spot ’ in Loch Creran
Paul Naylor discovers a world of diversity in a small patch of seabed in the sheltered water of a Scottish sea loch
Scottish sea lochs are a regular port of call for my occasional ‘ On the Spot ’ pieces where I look at the marine animal species you can see in a single photograph . Not only do they often boast impressive biodiversity and different habitats in a relatively small area , but their calm and clear diving conditions lend themselves to slowing right down and appreciating the wealth of life . This time , the focus is on a little patch of rocky outcrop in the inner basin of lovely Loch Creran near Oban .
Impressive large common sunstar on a Loch Creran reef
Common sunstar ( Crossaster papposus ) – it is front and centre of the photograph , but the wide-angle perspective is deceptive and this is only a youngster , a few cm across . These impressive predators can reach a diameter of over 30cm and engulf a wide variety of victims , with smaller starfish a particular favourite . Loch Creran is the only place where I have seen them spawn , a wonderful sight as they arch up onto their arm tips and , depending on the individual ’ s sex , release eggs or sperm . The eggs are unusually large , carrying yolky sustenance for the resulting larvae as these don ’ t feed while in the plankton , unlike the larvae of most starfish .
Cowrie ( Trivia sp .) – there are two common species of these attractive small molluscs in our waters . From close examination of the image , I suspect this is the Arctic cowrie ( Trivia arctica ) with no spots on the shell and a plain , unstriped ‘ tail ’. Cowries feed on colonial sea squirts and are often partly hidden among their prey rather than being out in the open . Looking at the photograph now , I wonder if this cowrie was about to be snaffled by the sunstar !
Close-up of a spawning common sunstar , showing the large orange eggs
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