As our waters warm we should expect to see changes in the fish and other life in our seas. Shellfish are a common and varied form of life along our coast. Are they showing signs of climate change yet? Maybe.
Shell collector, Wayne King of Bodalla, talked me through some of his large collection from which some specimens are pictured below.
Wayne rightly advises caution about attributing appearances or disappearances of certain shells to climate change. Sometimes a new species is discovered only recently even though it has been around for a long time. It’s simply that no-one has looked for it within living memory. Or perhaps a species disappears from a harbour area because of pollution or because a favoured food is in short supply.
Yet there are indications that shellfish species and populations are responding to climate-altered ocean ecology.
The bailer shell above at close to 12 centimetres long is a half-grown specimen. It is so named as it often grows big enough to use for bailing water out of boats. It is a tropical species, not known before in Eurobodalla waters.
Maybe it is moving south because of warming waters and/or a stronger East Australian Current, itself strengthening because of warming oceans, … or maybe there were bailer shells here all the time, just unnoticed.
Keep your eyes peeled for more of these to shed further light on Wayne’s unusual find.
These mid-sized guys (Cymbiola pulchra) are now found further south than Wollongong, the previous southern extent of their range. Is this due to climate change? Watch for these to answer that for yourself.
The humble limpets pictured above feed on algae growing on inter-tidal rocks. Whereas bigger shellfish can move to deeper therefore cooler water as surface water temperatures warm, these little folk have to stay in the inter-tidal zone and are therefore susceptible to warmth. Watch the humble ones.
The blue siphon shell (Siphonaria tasmanicus), which are the blu-tinged ones in the middle of the photo above the right-hand end of the ruler, will disappear from our coast if waters warm much more.
Jack Egan spoke with Wayne King in 2020
WOOEE 2022
