I think your best bet, if the account is a main type of account, would definately be to do Swan Song. From what I could tell while fishing on my pure, only ever got to like 79, was that sharks were really slow. I have heard it is only really great money to start sharks around 92-95. However, monkfish are much faster money overall and are easily botted, as are sharks. Tuna/Swordies were always a good option if I wanted to auto some cooking.