Hi Shireen, Well, my methods of picking dredging sites are not very sophisticated - it pretty much depends on where I can find boat-launching facilities, in an area where the bottom is not too rocky. As you said, coral reef bottoms would not be suitable for dredging - but here in the northeastern United States we don't have to worry about that. There is only one species of coral here, and it grows in little flat patches on rocks - no branches or brambles, and no reefs. The rocks themselves are the main problem to be avoided. Here in New England (for those who might not know, New England is a collective term for six states located at the northeast corner of the USA) there are many rocky shorelines. In some cases, the rocks are fairly small (egg size to fist size) and smooth. But in other cases the beach is covered with rough boulders ranging from basketball size to truck size. Usually (though not always) the nature of the substrate just offshore resembles that of the intertidal area - rocky bottoms off rocky beaches, sandy bottoms off sandy beaches, muddy boittoms off muddy beaches. Even off rocky beaches though, you can usually find sandy or muddy bottom if you get far enough offshore. A good quality depth finder or "fish finder" is useful in assessing the bottom type, as well as the depth. I don't have one however. I get my depth information the same way Columbus did - with a weighted "sounding line". Specifically I use a fishing reel with braided nylon line that I have marked at intervals with various colors of fluorescent paint. A 16 ounce (450 gram) lead weight takes it straight to the bottom, and I can read the depth by the colored marks where the line enters the water. Trying to dredge on a rocky bottom is not usually worthwhile. The dredge bounces and bangs along, often gets damaged, gets hung up on large rocks, and may become irretrievable either by filling with rocks, or more likely by getting wedged between two large boulders. Actually it is the chain which leads the dredge that is most likely to get wedged somewhere. There was one fellow I corresponded with years ago who did have some success dredging brachiopods ("lampshells") off rocky bottoms in the northwest. Brachiopods look superficially like bivalve mollusks, but they live very differently. They attach to rocks by means of a stalk, and the shell sits atop the stalk like a golf ball on a tee. Apparently they were quite abundant in his locale, and the dredge would clip off enough of them as it bounced over the rocks to make the effort worthwhile. However, he also told me that he carried three dredges on the boat, and at least once he lost all three of them on one trip. I only lost one dredge ever, while dredging on a flat mud bottom, 80 feet deep. I'm not sure what I "caught" (or rather what caught me) but I suspect it may have been a sunken fishing boat known to be in the area. Dredging on grass beds can be somewhat productive. A small dredge like I described in my previous posting won't rip up grass by the roots like a large commercial dredge or trawl would. On the contrary, it just bends the grass down as it moves along. This prevents the dredge from digging into the bottom, and actually even from touching the bottom. Therefore you won't pick up many burrowing bivalves; and, you won't get many gastropods that crawl on the surface of the sediment. What you will get is small snails that live on the actual blades of grass (in some areas there are amazing numbers of these), and also bivalves that swim, and come to rest on the grass, or attach to it by a byssus (in this area, primarily pectens and small mussels). Dredging isn't just for deep water. You can snorkle over a sand or mud bottom in a few feet of water and not see a thing. Yet a small dredge towed along the same path may yield many interesting specimens that were hidden just below the surface of the sediment. In such shallow water you don't necessarily even need a boat - you can tow the dredge manually if necessary. Make a large loop and put it around your waist - or tie the tow rope to the middle of a sturdy pole, and two or more people can work together, holding the pole horizontally and pushing on it like a yoke of oxen. Two variations on this theme are - a hand dredge (sort of a mesh scoop attached to a pole, that you can use manually, with a raking action); or screening - shoveling sediment onto a flat screen of suitable mesh, and sifting it through by shaking the screen (easier if the screen is held in the water while sifting). With either method, as in dredging, you don't have to dig in deep - most specimens of interest are in the top inch or two of sediment. What are you likely to get besides shells? Here's a partial list from my experience - sand dollars, seaurchins, sea cucumbers, sandworms, lugworms, tube worms, bloodworms, scaleworms, starfishes, brittle stars, sea robins, toadfish, pipefish, sculpins, flounders, cunners, skates, lobsters, spider crabs, hermit crabs, green crabs, rock crabs, blue crabs, horseshoe crabs, sea spiders, barnacles, amphipods, mantis shrimp, grass shrimp, coral, sea anemones, jellyfish, comb jellies, sea squirts, sea porks, sponges, seaweeds, dead shells, rocks, bricks, broken glass, bottles, cans, plastic bags, wood, a grapefruit, a Batman action figure, a pair of pliers, a Boston Red Sox hat - I guess you get the idea. That's why I recommend rubber gloves while picking through the catch. Note: before you toss back the wood, check for Piddocks and shipworms. Before discarding dead shells and bottles, check them inside and out for limpets of various kinds, and chitons. Regards, Paul M. Providence, Rhode Island, USA