Ishmael describes the “brit,” or bright krill-like organism that runs in long “fields” in the oceans. This brit is fed upon by the right whales that follow the Pequod—for the right whale is not good for oil, and is therefore not hunted. Ishmael closes the chapter by noting that the right whales are like lawn mowers, mowing the “grass” of the ocean and skimming off the brit as nourishment. Ishmael then muses that the sea is “subtle,” as it holds in its depths a great number of monsters not visible to the naked eye. The sea is filled with danger, and land is a place of serenity—and Ishmael notes that, in human souls, the same is true—that there is an “island” of peace surrounded by an “ocean” of fear and anxiety.
Ishmael describes right whales almost as if they are domesticated. But he uses this observation to then muse on something else, the fact that the beneath the peaceful right whales in the depths of the ocean live unseen monsters. He sees the ocean—unlike the land—as being a place defined by the unknown. That which is known is an island, surrounded by what isn't known. And once again Ishmael deftly connects this metaphor to men and life, which is similarly rich and dangerous with a surrounding unknown.