4.1.2 Abundance

The Penobscot River continued to support a substantial wild population during the late 1800's, with a reported commercial catch of over 10,000 salmon in 1880 (Baum 1997). In subsequent years, a new artificial propagation program initiated in Maine influenced population abundance and distribution. However, the abundance of Atlantic salmon generally continued to decline in all remaining rivers with salmon populations through the last half of the 19th Century and first half of the 20th Century. By the mid 20th Century, the total adult run of Atlantic salmon to U.S. rivers had declined from hundreds of thousands of fish in the early part of the previous century to a probable range of 500-2000 fish, mostly in rivers in eastern Maine (estimated from data reported in the Maine Atlantic Sea-Run Salmon Commission's River Management Report series published in 1983). One of the best years for angling harvest during the period from 1948 through 1970 was 1959 when a total recreational catch of 479 salmon was reported. Of these, 450 (94%) were caught in five rivers in Washington County (Baum 1997). The recreational catch reported for the Penobscot that year was only 2 fish. The primary distribution of Atlantic salmon in the U.S. by the mid-20th Century was, except for a few remnant populations, limited to the eastern third of Maine's coast.

4.2 HISTORIC STOCKING (1866 to 1970)

4.2.1 Stocks Used for Artificial Propagation

Artificial salmon propagation in Maine continued to use Penobscot-origin fish purchased from commercial trap-netters as the source of eggs into the 20th Century, when declining runs and pricing disputes resulted in a decline in availability of Penobscot salmon for brood stock. Canadian salmon stocks were increasingly used as a source of eggs for the Craig Brook Hatchery in East Orland, Maine, with the Miramichi and Gasp‚ Rivers becoming the primary sources in the 1920's and 1930's. The use of Canadian eggs declined in the 1940's when the Machias River and, for a brief time, the Penobscot again became a source of brood stock. During the 1950's and 1960's, the lack of Penobscot River fish resulted in Canadian salmon again providing a major source of eggs, supplemented with eggs from Machias and Narraguagus brood stock. Hatchery-produced juveniles were stocked as fry and parr, with poor results. The stocking of hatchery-reared smolts of mostly Miramichi and Narraguagus stock origin in the late 1960's brought about the successful rebuilding of the salmon run in the Penobscot (Baum 1997). The resultant adult returns enabled the Penobscot River propagation program to become self-sufficient for eggs and to support the egg needs of all artificial propagation in Maine by the 1970's. Later, this same stock of fish were transplanted into the Union River and comprised essentially the entire source of brood stock for the contemporary (post-1970) Atlantic salmon stocking program in Maine, until the advent of the river-specific propagation program in 1992. This same contemporary Penobscot stock is also the foundation of essentially all Atlantic salmon stocks now used for artificial propagation in the restoration of runs in historic salmon rivers outside of Maine.

4.2.2 Numbers and Life Stages Stocked in Key Rivers

The stocking strategy from the start of the artificial propagation program in the 1870's through the 1930's in the United States depended heavily on releasing fry. Most records indicate that early fry stocking methods were dominated by cluster stocking of large numbers of fry in limited areas of a river. Numbers released through artificial propagation programs prior to 1970 were greatest during the 40-year period from 1896 through 1936. These fish were released predominantly as fry. After a 60-year period of predominantly fry releases, the strategy shifted to focus on releasing parr and remained so through the 1950's. By the mid-1960's, the production and stocking of smolts replaced parr as the basic strategy of enhancement and conservation stocking programs (Baum 1997).

Numbers produced and stocked changed greatly, undoubtedly out of logistic necessity, when the target life stage for release changed from fry to parr or smolt. Fry production in the millions annually was common when fry were the focus. Numbers declined by an order of magnitude when hatcheries started to retain fry for rearing to the parr stage. The annual stocking of 1-3 million fry fell to 100,000-300,000 parr during and after the transitional decade of the 1930's. The artificial propagation program had only just started to focus on smolt production prior to the initiation of the contemporary salmon restoration program circa 1970. The production of smolts was on the same general level of numbers as parr at the only major facility in the U.S. producing Atlantic salmon at that time, Craig Brook National Fish hatchery in East Orland, Maine.

4.3 CONTEMPORARY STOCKING (1970-1992)

4.3.1 Stocks Used for Artificial Propagation

4.3.2 Numbers and Life Stages Stocked in DPS Rivers

The BRT acknowledges that historic stocking practices may have had an adverse effect upon the genetic integrity of local stocks. However, the capabilities of these early programs were limited in technology, distribution capabilities, and knowledge of stocking strategies. Available evidence suggests that these efforts resulted in only negligible adult returns from stocking. In fact, some reports document an increase in small salmon returns during stocking (Kendall 1935) that quickly reversed after broodstock were changed to native stocks. Poor hatchery return rates coupled with remnant natural stocks led the BRT to conclude that while some negative effects upon the genetic integrity of these stocks are possible, introgression could not have supplemented native genotypes within the Gulf of Maine DPS.