Montesquieu

In sea­ports, where men expose them­sel­ves to a thou­sand dan­gers and go to die or live in remote cli­mes, there are fewer men than women, yet we see more chil­dren there than elsew­here : this is owing to the ease of sub­sis­tence. It could even be that the oily parts of fish are bet­ter at sup­plying the mate­rial that goes into gene­ra­tion. That would be one of the cau­ses for the infi­nite popu­la­tion there is in Japan1 and in China,2 where they live almost exclu­si­vely on fish.3 If so, cer­tain monas­tic rules which require living on fish would be contrary to the spi­rit of even the legis­la­tor.

Japan is made up of islands ; there are many shores, and the sea is rich in fish.

China has innumerable streams.

See Father du Halde, vol. II, p. 139, 142 and following.