In the present essay I have endeavoured to bring together the most precise and reliable evidences available as to the recent and present condition of the great trawl and line fisheries of England and Wales. Both these fisheries depend for their success upon the same fundamental conditions, viz. the abundance of fish upon the bed of the sea. They may rightly, therefore, be grouped together under the single head of “bottom fisheries,” in contrast to the fisheries for herrings, mackerel, and pilchards, which are “surface fisheries.” From the nature of the case, even great fluctuations in the annual produce of the latter fisheries scarcely excite surprise, but a fairly constant yield is tacitly expected of the bottom fisheries, when the same apparatus is employed, owing to the greater uniformity in the conditions of life on the sea-floor.