One of the great things about doing research are the little aha! moments that come when you find something interesting–in this case, a clipping from a 1956 article in Pacific Fisherman, about the Japanese fishery for tuna in the Indian Ocean.
The article is about the expansion of tuna fishing into the Indian Ocean, and it quotes a tuna fisherman as saying that “the weight of the tuna population of the seas exceeds that of the human population of the world’s land masses.”
Asked about the presence of sharks in the water, Mr. Shinomiya admits there were severe shark depredations when the boats first started fishing.
“However, he finds that the shark population dwindles rapidly under the effect of the fishery, and becomes negligible by the time an area has been long-lined for three months. Thereafter it can be fished only with nominal damage from the in-coming sharks.”
We know now that sharks are very slow to mature and they are not a very fecund species. We have learned a lot since 1956.