THE SEASHORE AQUARIOLOGIST
A month by month survey of the
Sussex coast seashore fauna, from our native
marines expert, Andy Horton
(Photographs by the author)
One of the attractions of keeping British marine life found on the coast and in the shallow seas surrounding these isles, is that the aquarist can obtain firsthand knowledge of the conditions in which the fish and invertebrates live. I spent over two years fossicking on the seashore, exploring and studying wildlife, before I embarked on my first aquarium in which I endeavoured to provide conditions as near as possible to those found in the wild.
Rocky shores are the most interesting in terms of the variety of creatures suitable to keep for more than one year. Fish found on sandy shores rarely make good long-term tank inhabitants in the smaller home aquar-iums. The Flatfish quickly grow too large, and the small sandy coloured Gobies have a short natural lifespan of less than 18 months.
In Sussex, where the chalk cliffs have eroded over the centuries, the sea has channelled deep gullies in the soft rock, and broken large pieces of chalk into smaller fragments, providing numerous hiding places.
SUSSEX COAST REPORT (MONTH BY MONTH)
Shoreline: Rottingdean (Brighton) to Worthing.
This is a barren and unproductive month. The regular sessile inhabitants, the mollu-scs, mussels and winkles, are often covered in silt. Chitons are more noticeable on the underside of rocks. Even the Beadlet Anemones, Actinia equina, will have dwindled in size because of food shortages. Most fish and crabs will be found in the warmer offshore waters.
commonest and most widespread chiton found on British rocky shores is Lepidochitonacinerea.
On many shores it is the only species to be found.
In February, the sea temperature falls to 9°C (48°F), the lowest of the year. Nudibranchs, the orange and white Onchidoris bilamellata, and the white or black Acanihodoris pilosa, will migrate inshore and lay white coils of spawn on the underside of I small rocks near the low water mark. These sea slugs will die shortly afterwards. Look for the cream eggs of the Bullhead, Taurulus bubalis, on undisturbed shores. If you have waders and can brave the cold, February is the best month for shrimping.
At the Vernal Equinox for 1989, when the alignment of the earth, sun and moon produce the highest and lowest tides of the first half of the year. This enables the terrestrial aquarist to reach rock pools that are only uncovered at the equinoctial lows.
The Grey Sea Slug, Aeolidia papillosa, lays white spirals of spawn and then dies. In very small pools under rocks, the first fish begin to stay inshore. Butterfish, Pholis gunnellus, and the 5-Bearded Rockling, Ciliata mustela, are the most common, but juveniles of the Rock Goby, Gobius paganellus, are present in some localities.
Long-clawed Porcelain Crab, Pisidia longicornis
In areas with sand, the two species of Porcelain Crabs, Porcellana sp., tiny filter-feeding anomurans, cling tightly to the underside of boulders. The Common Starfish, Asterias rubens, and the attractive purple-tipped green Shore Urchin, Psammechinus miliaris, are colourful additions. They are not always to be found.
Early April is noted for the presence of the typical rock pool fish of British shores. The Blenny, Lipophiys pholis, will breed in the deeper intertidal pools. Congregations of this fish are likely to be present throughout the summer. The Common Goby, Pomatoschistus microps, abound in there thousands in shallow sandy-bottomed pools, in a frantic breeding season that continues until June.
All March visitors will remain. The Hairy Crab, Pilumnus hirtellus, and undersize Edible Crabs, Cancer pagurus, will wedge themselves in piddock holes and bury themselves in soft sand under rocks.
This month is characterised by the first extensive growths of weed in the pools. Large brown wracks drape themselves over chalk outcrops making the passage slippery and dangerous.
A veritable predator, the voracious smallish fish known as the Bullhead or Sea Scorpion, Taurulus bubalis, will be increasingly found preying upon young Gobies and Blennies, crabs and prawns. It hides in ambush for its prey, and is easy to catch in a small net.
This is not a particularly good month. Blennies and Bullhead should be present, but fish like the Rockling, may have moved into cooler waters just offshore.
A dramatic increase in the Shore Crab, Carcinus maenas, population is most noticeable. This abundant crustacean has a natural lifespan of about two years, but most of the young will perish before the end of the summer.
Prawns, Paleamon serratus, of edible size, will migrate inshore. Thousands will hide among the weed in the rock pools.
July heralds the first indications of an explosion of life. Under rocks the Squat Lobster, Galathea squamifera, can be present in tens of thousands. Sharing their living space will be starfish, urchins, numerous crabs, other crustaceans, anemones and small fish.
In pools and shallow water at the margins of sea and shore, four species are specially noticeable. The Bullhead will prey upon the ample prawns. A large pond or prawn net will also catch the fry of the Corkwing Wrasse, Crenilabrus melops, averaging 3 cm (1.2 in) in length. Fish of 5 cm (2 in) plus are the most successful in aquaria.
If you search carefully you are likely to discover the long-legged Spider Crab Macropodia rostrata, its long legs tangled in a mass, and resembling a clump of weed. It must be kept apart from aggressive predators, Blennies, Wrasse, and other crabs
Flounders and Common Gobies enter estuaries and swim into areas of low salinity.
The sea temperature rises to 17°C during this month, the highest of the year. It is the most prolific month for the seaside aquariologist. Almost all the fish have completed their breeding season and the pools abound with the young of Wrasse, Gobies, Blennies, Bullheads and Rocklings.
Invertebrates include small Hermit Crabs, Pagurus bernhardus, the ubiquitous prawns and crabs.
The remaining 6 months will be published later.
Wet Thumb (Marine Aquaria)