答案：

S1  mysterious S2  coupled S3  ruining S4  percent S5  species S6  ensure S7  average S8  When you consider that equals of a quarter the world catch you begin to see the size of the problem  S9 some countries are beginning to deal with this problem,but it's vital we find rational ways of fishing  S10 It would make sense to give the fish enough time to recover,grow to full size and reproduce