Are river fish considered "seafood" [closed]

I am confused whether river fish can be categorised under "seafood".

Welcome to EL&U. You are not the only person who is confused, looking around the internet there are a number of different definitions of 'seafood', even sources which can normally be considered reliable differ on this point.

For instance the Online Oxford Dictionary defines seafood as:

Shellfish and sea fish, served as food

which would include freshwater shellfish like freshwater clams and mussels, include sea fish like herring, tuna and cod but exclude freshwater fish like trout.

The Collins online dictionary on the other hand defines it as

shellfish such as lobsters, mussels, and crabs, and sometimes other sea creatures that you can eat

This excludes all freshwater creatures and says that fin fish are only included sometimes.

also Merriam Webster says it is

edible marine fish and shellfish

which includes sea fin fish but is not clear as to whether freshwater shellfish are included.

On the other hand Britannica.com says it is

edible aquatic animals, excluding mammals, but including both freshwater and ocean creatures

which definitely includes shellfish and fin fish from both salt water and fresh water. By the Britannica definition lobster, herring, freshwater clams, marine clams, cockles, prawns, trout, salmon and a whole host of other creatures are included and only mammals, birds and land dwelling creatures are excluded.

The California Department of Public Health defines shellfish as

seafood products, which include all fish and fishery products intended for human consumption

it then goes on to list all sorts of creatures, both freshwater and saltwater and including frogs an alligators as seafood!

Interestingly this cookery website compares various definitions including a very broad one from the US Department of Agriculture and a much narrower one from the Larousse Gastronomique. The discussion is worth reading but is far to long to copy here. However it ends with what I consider a very good summary of the argument from a cookery point of view which is

Generally, if someone sits down in a restaurant and orders a Seafood Antipasto, or a Seafood Salad, they are not expecting to see a hunk of salmon on it: they are expecting calamari, scallop, shrimp, shellfish, etc.

Unfortinately, when it comes to 'seafood' there does not seem to be a universal definition or any agreement as to whether fin fish of any kind or freshwater shellfish are included or not. It seems that many organisations use definitions that suit their own purposes.

It might be interesting to note that "sea-food" is predominantly an Amercian word. The Oxford English Dictionary lists a quote from Baugh's 1935 history of the English language that reflects this:

A writer in the London Daily Mail recently complained that an Englishman would find ‘positively incomprehensible’ the American words..sea-food,..and hired-girl.

The oldest citation in the OED is from 1836, but Google Ngram Viewer shows that the term "sea-food" has become more prevalent only since the 1940s:

Another citation from the OED illustrates this rise in the use of the term in the mid 20th century:

Twenty or thirty years ago..fish was upgraded to seafood. (K. Hudson, Jargon of Professions, 1978)

So maybe "sea-food" is as ill defined as @BoldBen has expounded in their answer because it is not the term used to speak of fish, shellfish, and such by most native English speakers.

Here's another quote from the OED for your delectation:

‘I hope you like sea-food.’.. ‘Sea-food?.. Fish, that is? Oh yes, I do, indeed.’ (..True enough, though this ‘sea-food’ set Charles thinking that he also enjoyed ‘land~food’.) (J. Hilton, Time & Time Again, 1953)