On a fairly regular basis, collectors of specimen shells are accused of being environmentally insensitive. Many people not involved in conchology are surprised to learn that the large majority of collectors are great believers in preserving ecosystems and avoiding damage to any population of organisms. In fact, a large proportion of our customers have degrees in biological sciences and many are actively engaged in scientific work for museums or similar institutions. Specimen shells get bought and sold and traded, and traded again, but most will eventually end up in the scientific collections of the major museums and will therefore contribute directly to our understanding of the ecosystems from which they came. This is one reason why collectors of specimen shells do not feel they are doing environmental damage.

But the major defence of specimen shell collecting – as opposed to commercial shelling or commercial fishing – is to do with the methods of selection. In any population of living molluscs, only a very small proportion are going to be what we'd call collectable condition. Responsible, modern collectors take only those individuals that they know they can use, and leave the rest as breeding stock. The impact on the population is therefore minimal, and is quickly made back up again. This contrasts with the commercial harvesting of some molluscs for food (eg abalones), or for use in industry (eg Trochus niloticus for buttons), or as tourist items (eg Strombus gigas), where there is no need to select for quality and no human resources available to do so anyway. Any of those activities can have significant local effects on molluscan populations and can unbalance ecosystems. By comparison, we believe that the effects of collecting specimen shells are negligible.

There are examples of irresponsible collecting techniques which are now thankfully outlawed or illegal. These include breaking apart live coral heads (using a crowbar or dynamite); collecting juveniles which haven't had the opportunity to procreate; and systematically eliminating a species from a locality by deliberately collecting every specimen. The responsible collector, on the other hand, takes great care to preserve the environment that he/she is collecting in – for instance, by carefully replacing every rock that has been turned over in the quest for shells. Most of our suppliers rely on shells for their livelihood and therefore have a strong vested interest in preserving populations of the shells.

The tangle net system is simple in theory, amazingly inefficient in practice, and yet is the only way to collect shells from many deep-water habitats short of hiring a mini-sub. A long net of wide-mesh line is dropped to the sea bottom using buoys at both ends to mark the position. It is put down in the evening in the hope that nocturnal molluscs will crawl into the net overnight; when it is hauled up in the morning they may become tangled and can be retrieved. The reality is that few specimens actually get tangled, and many of those that do simply drop out as the net is brought to the surface. Nevertheless, tangle nets have been responsible for the discovery of hundreds and maybe thousands of new species from depths of 300ft down to over 1000ft, particularly in the Philippines. The tangle net has minimal environmental effect because it totally relies on molluscs crawling into the net and getting trapped; therefore it can only ever collect a tiny proportion of the shells in the proximity. It is completely different from trawling with a net, or pulling a dredge behind a boat.

Our data labels always follow a standard format. They state the family, genus and species; the author(s) who described the species and the date. Where we have the information available, they include the habitat data (eg 'on sand', 'under rock' etc), the depth in feet, and the method of collecting (eg SCUBA, snorkeller etc). They always include the geographical data, although the degree of precision inevitably varies – some of our suppliers supply data that define a locality to within a few feet, while other suppliers are reluctant to give out detailed information. For more than half the shells we sell, we also give the date of collection (month and year).

Without a label giving the locality data for a shell, the shell has no scientific worth. The majority of specimen shells will eventually end up in museum collections (or at least we hope that they will!) and no museum will accept a shell without data. It's often said that the locality data are more important than the ID of the shell, since the ID can always be determined at a later date provided that the locality data are accurate.

Most of our shells are live-collected, and sometimes we make specific mention of this because live-collected specimens of some species are rare. The locality data for live-collected shells are much more valuable than for dead-collected or empty shells, and so live-collected shells are sought out by scientists. For instance, the data for a live-collected shell can provide important information about the habitat (eg buried in sand, or on an algae-covered rock); on the other hand, a dead-collected shell could be found hundreds of miles from where the mollusc actually lived.

Fake shells have been around for centuries, but it was only in the 1990s that they started to become a serious concern to collectors. Most fakes and doctored shells originate in the Philippines, but we are aware that some shells from elsewhere are exported to the Philippines and then 'doctored' by the local craftsmen there. The skill of these so-called 'Cebu doctors' is amazing, and their techniques continuously evolve. We examine all Philippine shells very closely before we offer them for sale, and we think you are as safe buying from us as from any dealer worldwide. Although some dealers sometimes offer repaired shells and describe them as such, which is not itself dishonest, we never accept any repaired shells sent to us because we don't want to encourage this practice.

Fishermen around the world have a habit of 'smoothing' the lips of some shells, most notably Conus, and this is infuriating to the vast majority of serious collectors. We constantly try to eliminate this, since it changes the shape of the lip and therefore the characteristics of the shell. Nevertheless, you'll occasionally see Conus advertised on our list with smoothed lips. We don't regard this as 'doctoring', but we try to make it clear on our list because many collectors won't want these shells. The price of the shell will always reflect this alteration.

Absolutely. We will keep your list for as long as you want, and inform you if shells become available.

Certainly. It is best if you tell us a minimum size for the shells you want to buy, a maximum price per single shell, and tell us what features you find most satisfying – spines, bright colours, eye-catching patterns etc. We'd like to know if there are some groups in which you aren't interested – bivalves or landsnails for instance. And, of course, you need to tell us if there are particular families that you like.

It really is entirely up to you. We know collectors who want examples of every molluscan family and whose collections even include non-shelled species such as slugs and nudibranchs. Some collectors eventually narrow themselves down to a group of related families (eg Cassidae, Ranellidae, Personidae and Bursidae) or collect the 'big four' gastropod families (Cypraeidae, Conidae, Muricidae, Volutidae). Others are amazingly specialised and try to obtain every named colour form of a particular family or genus. There's no 'right way' to do it. In financial terms, if you remain a general collector you can continue buying large quantities of shells for many years and always be adding new species to your collection, whereas the specialist collector eventually has to spend large sums of money on single specimens of the rare species.

I'm asked this all the time, and like for many shell enthusiasts it's not terribly easy to answer. In the early 1990s I was fortunate enough to live close to the Delaware Museum of Natural History, which houses one of America's finest scientific collections of shells. I became involved with the Wilmington Shell Club that is based at that museum, and then started working in the museum collection as a volunteer Research Associate. By then I was well and truly 'hooked'. By coincidence, my professional life overlapped with malacology rather nicely: my background is in pharmaceutical research and at that time I was doing experimental work with Conus toxins for a drug company.

Since I sell such a variety of shells, I am not supposed to have favourites! But I confess a particular affection for the Volutidae, Conus, and some of the deep-water groups such as Columbarium. I like landsnails, the 'odd' families that hardly anyone collects, and all kinds of freak specimens. I tend towards specimens with superb colour rather than large size – a preference that you'll often see reflected in the list.