The Salmon Fishery

Salmon migrate towards the upstream waters of aa river where the rapid current maintains high dissolved oxygen levels that are necessary around the eggs.  The best location for fishing migrating fish like the Atlantic salmon are near falls or rapids.  This is also where most of the first human settlements occurred along the Merrimack.  For example, at the Amoskeag Falls, where the river falls fifty-four feet in the space of a mile, the fish tend to congregate behind large rocks to seek shelter against the force of the falls.  This has made them easy prey for fishermen.

The salmon were extremely abundant at the time of European settlement.  Since the foundation of Boston in 1630, huge wagon loads of fish were brought from the Merrimack River fishery to the Boston markets (Dunfield, 1985).  Demand was very high.  But soon enough, periodic declines in the stock were experienced.  Good runs were almost annually guaranteed until the end of the 17^th century.  However, this abundance decreased by the 1700s.  By the late 1720's seasonal failures were commonplace and by the 1750's the Merrimack fishery was beginning to show a considerable decline.

In addition to the growing domestic and especially commercial fishery, the fish encountered a greeter menace - dams.  By 1815 the waterways were being rendered inaccessible due to these man made barriers.  Hence after 1846, the American markets became increasingly dependent on imports from British North American waters.  These imports had grown from 0.75 million pounds per year in 1832 to 1.25 million pounds in 1843 and 2.25 million pounds per year in 1848, with demand still growing.  An 1867 assessment of the fishery reported that salmon and other freshwater species that were abundant half a century prior, furnished abundant and wholesome food to the people; but due to the impassable dams, pollution in the ponds and rivers as well as unregulated fishing, the population of these fish had plummeted.  Because of these reasons, fisheries on the Merrimack River came to a stop by the middle of the nineteenth century.  Though the pollution was an important contributing factor, it was the gigantic Lawrence dam that was most decisive.  The fish were stopped dead in their tracks right before the dam, unable to pass upstream to their spawning grounds.  Before the dams came in the only obstacles for the fish were natural barriers like waterfalls which the Atlantic salmon were able to pass.  The Atlantic salmon can clear a height of up to eleven feet.  The dams succeeded in obstructing the path of the less powerful swimmers as well as the smolts that passed downstream.

In addition to overfishing, and the fish not being able to spawn, there are other factors that could influence the Atlantic salmon populations.  The physical characteristics of the river like temperature, volume, chemical balance all affect the reproductive ability of the fish.  Temperatures above 27^o C could kill the eggs and higher temperatures could cause the fish to develop more rapidly and migrate to the ocean earlier than expected (Steinberg, 1991).  Pollution by the adjacent industries could cause temperature fluctuations.  The volume of the water also affects the population size.  A low volume, perhaps because of low rainfall or other human induced causes, could result in a tendency toward smaller surviving populations.  The upstream migration of the salmon is dependent on there being a certain flow regime available.  The restraining of water by the dam decreases this downstream flow which could obstruct the upstream migration of the salmon.

The economy of the United States has always been one that is market driven with fish as a cash valued commodity.  Fishing played an important role in the economy of New England.  Also the importance and value for private property in the US has made other areas common resource areas free for exploitation by anybody and everybody who had the resources (Steinberg, 1991).  The same is true for the fisheries which experienced a tragedy of the commons ultimately leading to their over exploitation and complete decline.

The survival and maintenance of the Atlantic Salmon is dependent on man providing them with clean and passable waters, nursery grounds, and controlled fishing.
 
 
 

Back to Atlantic Salmon Introduction Page