The reviewer is right. The first sector is a macro conception of agriculture. It indeed includes fishery. However, the data of output and employment are both collected on this level - the first sector. Hence, we assume the quotient of the two variables is a proxy to agriculture labor productivity. Meanwhile, they are the only available data on the prefectural level to calculate agricultural labor productivity. Therefore, we think this calculation is still helpful.
On the other hand, in the same line of text (pg. 4 line 3), the authors define the denominator of the agricultural labor productivity as the employed labors in the first sector. What does this first sector mean? Is it a synonymous of agricultural sector? If this “first sector” includes the fish workers, the agricultural labor productivity measures are not correct in the regions with sea access. In this case, it would be the primary sector labor productivity. The authors should also clarify if this sector included the forest products and labor.