The plural of moose is moose. Not meese, not moosen, not mooses. Just moose.
Most words in English came from other languages. The word goose is German, and did this fancy thing called strong declension to change into geese as a plural. Moose is a Native American word, and came into English around the 17th century, thousands of years after goose. This means strong declension was never applied.
In English, mass nouns like meat typically don't change as plurals. This includes animals like deer and salmon, meats like beef and pork, and other nouns like sand and mud. In English, you'd say “would you like some more salmon?” and not “would you like some more salmons?” The same concept applies to moose.