Most people start collecting shells by finding them themselves. This is often a very satisfying way whose only drawbacks are that it can be very time-consuming and that travel can be expensive.
Beachcombing is certainly the most common method of collecting shells: almost everybody has picked up shells from the beach at one time or another, while vacationing on the coast.In Europe, beachcombing gives good results along the beaches of the Atlantic Ocean, but it is often a waste of time for the collector visiting Mediterranean sandy beaches. This is mainly due to the absence of tides. However, virtually every beach can be productive at one time or another, especially after storms. You will probably find only badly worn remains of large shells on stony or pebble beaches. Of great interest is "shell grit" which is deposited along the tide lines. In this grit or "shell sand" you can find several thousands of small shells. Using a rake just before and after low tide, you may be able to find many of the species that live buried in sand. You may also find buried shells, such as Natica, Nassarius and Solen by recognizing the tracks they leave on the surface.
A close examination of mud flats exposed at low tide can produce many shells not found in any other environment. Like on sand, on the mud flat the collector can use a rake or hand dredge, as well as a spade to dig out the deep burrowing bivalves. Being able to recognize the tracks left by crawling or digging mollusks plays an even greater role here than on the sandy beaches. A word of warning, mud can be a deadly trap and it is advisable to find out about the site and the tides.
While sand and mud is better suited to bivalves, rocky coasts are often the home to many gastropod species. The collector can expect the best finds during the low spring tides. A flat knife and a long steel bar, slightly curved at one end, are standard equipment for hunting shells along rocky coasts. The knife will help you to prise shells such as limpets off the rocks, and the steel bar is useful to reach animals which are hidden in rock crevices. Examine all the tide pools, the small caves and the algae. Do not forget to look under rocks.
THE OPEN SEA
Diving, dredging, and fishing for shells are very good methods to collect species that live out of the tidal range. However, all these methods require experience and often much expense.
DIVING AND SNORKELING
In shallow water you can "snorkel" with a minimum of standard equipment snorkel, mask, and flippers. Good lungs are important: the working depth is generally limited to 12 m. Better results are usually obtained by scuba-diving. Air tanks permit the diver to explore the sea bottom thoroughly after suitable training. This method allows the shell collector to dive down to depths of 80 m, but 40 m is usually the limit for safe diving.
A dredge usually consists of a special net, which is designed to be pulled by a boat and dragged on the sea bottom. This can be a very productive way of collecting down to 60 m with a small boat. Museums and major institutions with proper research ships can dredge to depths of several kilometers and, in this way, can build up collections of deep sea fauna which is otherwise impossible to obtain.
Many mollusks are edible and thus are important to the fishing industry. Specimen shells are often a by-product of this industry. In the Mediterranean, many of the larger species, from Natica to Charonia are eaten, so a visit to the local fish-market is often useful. While in the Mediterranean it is often possible to find shells in nets that are being cleaned in the port, the fishing industry on Atlantic coast tends to be of a different type, and most of the ships arrive in the harbor, perfectly clean and without any shells.
From Poppe & Goto, European Seashells, Vol. I.