Rangeley Lake Fishery Management

FISHERY INTERIM SUMMARY REPORT SERIES NO. 02-1

by Forrest R. Bonney

Maine Dept. of Inland Fisheries & Wildlife
Fisheries and Hatcheries Division
Augusta, Maine

January, 2002

JOBS F-103 & F-104

INTERIM SUMMARY REPORT NO. 8 (2001)

Summary

Rangeley Lake, located in Western Maine’s Franklin County, provides an exceptional fishery for landlocked salmon. This 6,000-acre lake has a one-salmon daily bag limit, and is closed to ice fishing. The fishery is primarily dependent on annual stockings though wild fish make up a meaningful portion of the catch.

The salmon population was monitored by annual fall trap nettings at the Outlet and by annual voluntary angler surveys. Voluntary angler records indicated continued excellent catch rates of 1.3 legal salmon per angler in 2001; 69% of the anglers caught at least one legal-size fish, and they continued to release a high proportion of the legal catch. Both voluntary angler data and samples from the Outlet indicated that salmon growth rates declined moderately in 2001. Wild salmon accounted for 22% of the trapnetting catch at the Outlet; older salmon (age IV+ and greater) accounted for 30% of the catch.

Spring-yearling brook trout have been stocked in relatively small numbers at Rangeley Lake in recent years. Voluntary angler records confirm that these fish are continuing to contribute to the fishery, and we will continue to stock them as long as smelt, the primary forage base, remain abundant.

JOBS F-101

INTERIM SUMMARY REPORT NO. 8 (2001)

This report summarizes results of the 2001 Rangeley Lake voluntary angler records for both Rangeley Lake and Rangeley River as well as the 2001 landlocked salmon fall trapnetting at Rangeley Outlet. The results are compared to those of previous years. Season-long clerk surveys and angler counts are conducted every-other-year at Rangeley Lake; the last such survey was conducted in 2000 and the results were reported in Interim Summary Report No. 7.

Forage status is evaluated annually through qualitative assessment of post-spawning smelt egg abundance in the tributaries. Evaluations are typically conducted the second week of May by walking the streams after spawning is considered to be complete. The tributaries surveyed include Long Pond Stream, Dodge Pond Stream, Swains Brook, Nile Brook, and several smaller unnamed brooks. The 2001 egg-drop was considered to be moderate in terms of overall distribution of eggs and egg density.

Voluntary anglers reported average of 85 fishing trips per year from 1997-2001 (Table 1). Their data confirm that salmon fishing quality at Rangeley Lake remained high in 2001 with 69 % of the anglers successful in catching a legal-size salmon and a catch rate of 1.27 salmon per angler (Table 2). The salmon they caught averaged 18 inches in length. The proportion of legal-size salmon voluntarily released has exceeded 60% since 1997 but was lowest when growth rates were the best. It seems likely that anglers reject fewer legal-size salmon before choosing one to harvest when growth rates are excellent.

Voluntary angler records summarizing the Rangeley River fishery (Table 3) indicate a decrease in the number of sublegal salmon caught and an increase in the number of legal salmon caught. Of the legal-size fish caught, salmon and brook trout averaged 19 and 10 inches in length, respectively, in 2001. Variations in the number and size of fish caught within the last 5 years are attributed to the small sample sizes rather than changes in the population.

Data collected during fall trapnetting at the Outlet (Tables 4, 5, and 6) indicate a moderate decrease in salmon growth rates in 2001. The 2001 condition factor (a weight-to-length ratio that measures robustness) of 0.89 for all salmon sampled at the Outlet was less than that for 2000 or 2001, which were 1.01 and 0.99 respectively. Statistical comparison of average salmon weights by origin and age (Table 7) indicates a significant decline from those sampled in 1999 and 2000 for most categories. In an effort to maintain the excellent salmon growth rates experienced in 1999 and 2000, the salmon stocking rate will be reduced by 500 fish in 2002.

The number of salmon trapnetted at the Outlet of Rangeley Lake has remained high since the one-salmon limit was imposed in 1988. Typically, salmon move into the Outlet the first or second week of October and remain there throughout the fall. The trapnet catch rate of salmon at the Outlet in the falls of 2000 and 2001 were later than usual due to low flows resulting from dry weather. Nonetheless, we sampled 173 salmon in 2000 and 172 salmon in 2001 over an extended trapnetting season.

The proportion of older-age (age IV+ and greater) salmon in the trapnet catch increased from an average of 17% from 1989-1992 to 29% from 1993-1996 but declined moderately to 26% from 1997-2001 (Tables 8, 9, & 10). Older-age wild salmon accounted for an average of 44% of those sampled from 1997-2001 compared to 19% of the hatchery-reared fish; wild salmonids typically have greater longevity than those that are hatchery reared. The presence of a total of seven age VII+ salmon in the 2000 and 2001 trapnetting samples is noteworthy given that fish of this age have been sampled infrequently in the past; in those few years that age VII+ salmon were sampled, no more than one fish has been taken since 1984 when five were captured. The abundance of older-age fish is important both to provide a quality fishery and to maximize reproductive potential.

The superior longevity of the wild fish is explained in part by the relative ages at which the two groups are recruited into the fishery. Hatchery-reared fish, which have a size-advantage at stocking, attain legal-size at age II+, while wild fish do not become vulnerable to harvest until age III+. Hatchery-reared salmon are therefore vulnerable to harvest, on the average, a year earlier than their wild counterparts.

Although a few precocious age I+ males were captured at the Outlet, the youngest age group sampled in large numbers was age II+ male salmon (Table 11). Of the males, age II+ and III+ fish were most abundant; of the females, age III+ and age IV+ fish were most abundant. There were substantial numbers of age V+ fish of both sexes. A combination of the current regulations and angler propensity to voluntarily release legal-size fish are allowing a relatively large proportion of the salmon to survive to older ages.

The percentage of wild (unmarked) salmon captured at the Outlet was 11% from 1963 to 1974 (Howatt 1995) and increased from 19% in 1989 to 43% in 1996. Since then, the percentage of wild fish has varied between 20 and 36%; it was 29% in 2001. The increased proportion of wild salmon probably resulted from increased spawning success in the tributaries as more adult fish escaped harvest in recent years, though there may have also been some successful spawning downstream of the screens for several years while they were in disrepair.

Virtually all of the salmon sampled at the Outlet are sexually mature (Table 12). Substantial numbers of mature males – of both wild and hatchery origin – are present as age II+ fish. There are substantial numbers of mature age III+ female hatchery fish, but the majority of the wild female fish do not mature until age IV+.

Salmon originating from eggs taken at Sebago Lake were stocked in Rangeley from 1987 to 1994 and from West Grand Lake from 1995 to 2000; both strains were stocked in equal numbers in 2001. The mean proportion of older-age Sebago salmon stocked from 1985 to the present is 19%, less than the 22% for West Grand fish stocked from 1995 to the present (Table 13). Expressed as a percentage of the number stocked, numerically higher proportions of the West Grand fish have been sampled at ages III+, IV+, and V+ (Table 14).

Hooking injuries were documented for the first time in 2000 and will be documented in the future as an indicator of whether the increasing tendency toward catch and release is resulting in more injuries. The percentage of hooking injuries increased from 22% in 2000 to 38% in 2001 (Table 15).

Long-term management goals for brook trout include the stocking of spring yearlings when forage is abundant and investigating the feasibility of restoring the wild brook trout population through habitat improvement measures on South Bog Stream, the lake’s primary historical brook trout nursery. Additional measures include limiting brook trout stocking to the Kennebago strain, which is indigenous to the drainage. Future stockings of brook trout will be marked by fin excision to assist in age determination and to differentiate between stocked and wild fish.

Written by Forrest Bonney

For more information, please contact:

Forrest Bonney, Regional Fishery Biologist
689 Farmington Road
Strong, Maine 04983-9419
Telephone: (207) 778-3322 Ext. 22
Email: forrest.bonney@maine.gov