Native alewives deserve a fair shake

In his May 3-4 outdoors column, Tom Hennessey reported his fishing success at Hermon Pond has declined in recent years. He attributed this decline to the removal of two dams on the Souadabscook Stream in 1998 and 1999 that allowed native, sea-run alewives to free-swim from the Penobscot River to the various ponds on the Souadabscook.

Hennessey should exercise caution in attributing his recent spell of poor fishing at Hermon Pond to sea-run alewives. There are numerous other factors that can affect angling success from day-to-day, month-to-month and year-to-year on any given water.

For example, increased difficulty in “rousting a smallmouth bass from its spawning bed” at Hermon Pond, as Hennessey reported, is more likely due to an increase in the amount and sophistication of angling pressure on these bass. Smallmouth bass, being a long-lived species in northern climates, become “educated” over time and increasingly sensitive to human disturbance, especially while nesting, as interactions with anglers increase.

Furthermore, any recent decline in smallmouth bass populations at Hermon Pond, if occurring at all, is more likely due to competition with the recent illegal introductions of black crappie and largemouth bass. Unlike sea-run alewives, these exotic fish species are closely related to smallmouth bass and share a similar life history.

Hennessey further indicates that angling success for these recently introduced exotic species has also declined since 2000. However, considering the short period these species have inhabited Hermon Pond, any changes in abundance, if indeed occurring, are more likely a product of the classic “boom and bust” situation that often follows the introduction of exotic fish species. Eventually, natural forces will shape and balance the populations of these “new” species, and they will stabilize at some future intermediate level. This balancing can take up to 20 years or more depending on the species and habitat involved.

Recognition of complicating factors such as these is why most experienced fisheries managers, while routinely monitoring angler success both directly and through voluntary record keepers, utilize such information extremely carefully in terms of drawing conclusions about changes in populations of fish. Instead, such information is more often used to point managers to particular waters where more scientific and controlled population studies may be needed to determine what is actually happening there. Hennessey’s mention that some anglers had good success at Hermon Pond, during the period when he experienced lesser success, illustrates the danger of selectively using angler success data alone to draw conclusions about fish populations.

The only scientifically credible study of the sea-run alewife issue in Maine waters, that I am aware of, is the recently completed ten-year effort conducted by the Maine Departments of Inland Fisheries and Wildlife, Marine Resources, and Environmental Protection at Lake George in Canaan, which drains into the Kennebec River. Lake George was chosen as an appropriate site to study the interactions of sea-run alewives on both cold and warm water game fish and their prey.

The study failed to find any negative impacts of sea-run alewives, stocked at six adult fish per acre, on populations or growth rates of smallmouth bass, chain pickerel, yellow perch, brown trout, rainbow smelt or other fish studied. The study did find increased abundance of species of plankton preferred by smelt as forage, and increased growth rates for young smelt, during the period when sea-run alewives were present in Lake George.

Finally, Hennessey’s column seeks to lump management issues that may be related to restoring sea-run alewives to their native habitat, with issues related to “landlocked” alewives occurring in lakes where they never occurred historically, such as the Great Lakes. Considering the vast differences in life history between these two “forms” of alewife, this is an apples and oranges comparison and is an inappropriate approach for evaluating effects of sea-run alewife restoration.

Sea-run alewives, and their larger cousins, the American shad, once ascended the Penobscot River by the millions each spring. However, over the past 150 years, alewives and shad have almost completely disappeared, due primarily to water pollution and inadequate or nonexistent fish passage at the many dams constructed over the past two centuries. Because of this disappearance, alewives and shad have also been lost from our riverine culture and traditions.

The Penobscot Indian Nation views the successful restoration of native alewives to Souadabscook Stream as a small but important step in restoring all native sea-run fish species of the Penobscot to their historic place of prominence and abundance, and restoring the lost historical connections between the ocean, the river, and the fish, wildlife, and people that inhabit the Penobscot River watershed.

Clem Fay is a fisheries scientist who serves as fisheries manager for the Penobscot Indian Nation at Indian Island in Old Town.