Seing as all the seas are connected, why does the Torah refer to them as "Yamim" (plural)?
Rashi: Because the taste of fish that one catches in Acco is not the same of fish that one catches in Spain.
Why does the Torah refer to the seas as "Mikveh Mayim"?
Parah 8:3: To teach us that the seas are not eligible for the Tevilah of Zavim and Metzora'im, or to mix with the ashes of the Mei Chatas - all of which require spring-water. 1
See Torah Temimah, note 43.
QUESTIONS ON RASHI
Rashi writes: "'Seas' - Is [the ocean] not [just] one sea? Rather, [because] the taste of fish that emerges from [various locations] is distinct." But perhaps the plural is used merely because of the various rivers and water sources that flow into the ocean?
Gur Aryeh: That cannot be the reason, for upon reaching the ocean, the various waters blend together. The fish, however, retain the distinct taste of their waters of origin.
Rashi writes: "... The taste of fish... in Akko, is distinct from ... in Aspamya." Mizrachi asks - we are trying to explain the plural word "seas" that is used in regard to the ocean, but these locations are not on the ocean!
Gur Aryeh: The fish travel, along with the waters, from these locations to the ocean, yet they retain their distinct tastes. That is why the verse uses the word "seas" in plural. 1
Chazal specifically use these two places as examples, to teach that the ocean contains water from numerous sources, whose various identities are retained in the tastes of the fish they bring.
