Editing Shellfish (section)

==Terminology==
[[File:Rheinische Muscheln.jpg|thumb|180px|right|Cooked [[Mussel#As food|mussel]]s]]The term "shellfish" is used both broadly and specifically. In common parlance, as in "having shellfish for dinner", it can refer to anything from clams and oysters to lobster and shrimp. For regulatory purposes it is often narrowly defined as filter-feeding [[molluscs]] such as clams, mussels, and oyster to the exclusion of [[crustacean]]s and all else.<ref>[http://textonly.mde.state.md.us/CitizensInfoCenter/FishandShellfish/harvesting_notices/index.asp Maryland Shellfish Harvesting Areas] {{webarchive|url=https://web.archive.org/web/20061011102911/http://textonly.mde.state.md.us/CitizensInfoCenter/FishandShellfish/harvesting_notices/index.asp |date=11 October 2006 }}, Maryland Department of the Environment</ref>

Although the term is primarily applied to [[Marine (ocean)|marine]] species, edible [[freshwater]] invertebrates such as [[crayfish]] and river [[mussels]] are also sometimes grouped under the umbrella term "shellfish".

Although their shells may differ, all shellfish are invertebrates.  As non-mammalian animals that spend their entire lives in water they are "fish" in an informal sense; however, the term ”finfish" is sometimes used to distinguish [[fish]], animals defined by having [[vertebrate|vertebrae]], from shellfish in modern terminology.

The word "shellfish" is both singular and plural; the rarely used "shellfishes" is sometimes employed to distinguish among various types of shellfish.<ref>{{cite book | title=Fishermen: A Community living from the Sea | page=119 | last1=Festing | first1=Sally | year=1999 | location=Stamford | publisher=Shaun Tyas | isbn=978-1-900289-22-1 | edition=Revised}}</ref>