The Mackerel Purse-Seine Fishery - Seine-boat and crew
Seine-boat and crew "pursing the seine." The net has been rowed around the mackerel school to entrap it, and now the fishermen are hauling it in. The dory on the left pulled the seine around the school while the net was fed out.
Once they have the seine pursed up, the schooner will come alongside, hoist the net further, and dip out the mackerel.
This image is from G. Brown Goode's The Fisheries and Fishery Industries of the United States,1884-1887, Section V, Plate 63. The book can be found on line at: http://celebrating200years.noaa.gov/rarebooks/fisheries/welcome.html