此题问,当考虑海洋保护区到底是否能enhance fisheries(改善捕鱼业),作者这里说的改善主要指的是什么?根据题干26行我们找不到对应的改善指标,但是往后读一句我们找到了“higher density”,“greater catch per unit effort”,这些都是让渔业获益的指标。所以同义改写,选B:bolster the fishpopulations residing within fishing grounds。A选项:cause marine habits to revert to an unspoiled condition,没有提及未被破坏的状态,不符合。C选项:stimulate healthy competition among commercial fishing operation,没有提及刺激竞争。D选项:create demand for previously unharvested fish species,没有提及之前未被收获的鱼。