Dear Alfonso;-
    A "tide line" is the line of the last high tide. It is somewhat variable.
It is usually marked with a line of very light debris that looks like coffee
grounds. A number of small light shells may be found there: Dentalum, Olivella,
Epitonium, etc.
    The intertidal zone is the area between low and high tide.
    "Shallow" and "deep" waters is also up for grabs. I would assume "shallow"
to mean water not too deep to stand up in. A diver may consider 60 feet
"shallow".
    I will not attempt to translate meters into fathoms. I still don't know how
many square feet there are in an acre.
        Art

Alfonso Pina wrote:

> Dear CONCHLers,
> I have some troubles in the translation of some usual english terms
> referred to the depth in wich molluscs could be found. I think I understand
> them more or less, but I wnat not to make some mistake.
> What is the diference between tide line and intertidal zone? Is this tide
> line upper tide or lower tide line? or something between?
> When you use the term offshore, are you pointing just the line where water
> and land contact or something more? (let´s say two feet deep)
> What depth do you consider "shallow waters" and "deep waters"?
> And after all that, could somebody tell me the equivalence in meters of a
> fathom?
> Tank you very much.
> >From a sunny Malaga (17º C),
>
> Alfonso Pina
> Malaga
> Spain