New England Salmon Hatcheries and Salmon Fisheries in the Late 19th Century

by Various

The salmon placed in this inclosure had to be carted in tanks of water overland about a mile in addition to transportation in floating cars from 3 to 5 miles; they were transferred suddenly from the salt water of the river (about two-thirds as salt as common sea-water) into the entirely fresh water of the lake. To all the supposed unfavorable circumstances must be added the high summer temperature of the water. During August the mean was generally above 70 degrees Fahrenheit at the bottom and several degrees warmer at the surface. Occasionally there was observed a midday temperature of 74 degrees F. and once 75 degrees at the bottom. Yet this proved an excellent place for our purpose, a satisfactory percentage of the salmon remaining in perfect health from June to November.

No. 4. The inclosure in use since 1870 at Dead Brook, Bucksport. It is located in a gently running stream bordered by marshy ground, with a bottom in part of gravel but mostly of mud, crowded with aquatic vegetation. The water, supplied by two small lakes among the hills, is cleaner than the average of Maine rivers, but does not in that respect approach the water of inclosure No. 1. The greatest depth is about 8 feet, but in the greater part of the inclosure it is from 3 to 5 feet. The width of the stream is from 2 to 4 rods, and the portion inclosed is 2,200 feet long. The barriers to retain the fish are in the form of wooden gratings, with facilities for speedily clearing them of debris brought down by the stream.

Better results were expected from this inclosure than from No. 3, but have not been realized. The percentage of salmon dying in confinement has been greater, amounting commonly to about 25 percent of those introduced, and this notwithstanding the salmon are conveyed to the inclosure by water carriage the entire distance (7 miles) instead of being carted in tanks.

The cause of the trouble has not yet been discovered, but there is good reason for thinking that it lies in some of the circumstances attending the transfer of the fish from the place of capture, and that the inclosure itself is perfectly suited to its purpose. This view is supported by the fact that nearly all the losses occur within a few weeks after the introduction of the salmon and almost wholly cease by the end of July. If the cause of disease was located in the inclosure, we should expect it to be more fatal after a long than a short duration of the exposure of the fish to its action, and that with the smaller volume and higher temperature of August it would be more active than in June and July.

The above description will, I think, give Dr. Bottemanne a sufficiently correct idea of the character of the inclosures we have tried. There are, however, several other points to be touched upon to put him in possession of the practical results of our experience.

The facilities for the recapture of the salmon when the spawning season approaches must be considered. In the lake at Bucksport village (No. 3) we hoped at first that their desire to reach a suitable spawning ground would induce them all to enter the small brook that forms the outlet, which was within the limits of the inclosure. In this matter our expectations were but partially realized. Many of the fish refused to leave the lake through the narrow opening that was afforded them, and were only obtained by pound-nets, seines, and gill-nets, all of which involved a considerable expenditure of labor and material.

The drawing of a seine in a large body of fresh water is likely to be a serious undertaking unless the bottom has been previously cleared of snags. In this respect the long and narrow inclosure at Dead Brook possesses great advantages, since it can be swept with a comparatively short seine. However, the influx and efflux of a considerable volume of water is of great advantage in enticing the gravid fish into traps that can readily be contrived for them by any ingenious fisherman.

The existence of a gravelly bottom in the inclosure must be considered a positive disadvantage, inasmuch as it affords the fish a ground on which they may lay their eggs before they can be caught; but the danger of such an occurrence is less as the bounds of the inclosure are more contracted and the facilities for capturing the fish are better.

As to the number of fish to a given area, I think we have never approached the maximum. I should have no hesitation in putting 1000 salmon in the inclosure at Dead Brook, which covers an area of less than 3 acres. Of course the renewal of the water supply, or its aeration by winds, is of importance here.

The capture and transport of the fish in June involves methods requiring some explanation. The salmon fisheries about the mouth of the Penobscot River are pursued by means of a sort of trap termed a "weir." It is constructed of fine-meshed nets hung upon stakes, arranged so as to entrap and detain the fish without insnaring them in the meshes. They swim about in the narrow "pound" of the weir until the retreating tide leaves them upon a broad floor.