Malan, have you perhaps tried looking in our dictionary? If you look up repertoire, it says:
1. all the plays, songs, operas, or other works collectively that a company, actor, singer, dancer, etc, has prepared and is competent to perform
2. the entire stock of things available in a field or of a kind
3. in repertoire ⇒ denoting the performance of two or more plays, ballets, etc, by the same company in the same venue on different evenings over a period of time: ``Nutcracker'' returns to Covent Garden over Christmas in repertoire with ``Giselle''
The first sense is the relevant one. The author has extended that meaning so it is as if baleen whales had a number of things they can perform. If their repertoire is limited, there isn't much that they can perform!
So the sencence "Large baleen whales primarily use the lower frequencies and are often limited in their repertoire." actually means that lower frequencies limite the baleen whales to perform all kinds of shows?
Got it! Thank you sooo much!
btw, My mom always citisize me begin with " malan, have you.......or malan,why don't you...." ,so you'r a kind of feeling like my mom, dispite your age and gender!
Really appreciate your help!