Inland Seas Angler
GREAT LAKES BASIN REPORTÓ
A Publication of the Great Lakes Sport Fishing Council May 2004
http://www.great-lakes.org Vol. 15, No. 5
Highlights of the Great Lakes Fishery Commission's Lake Committee Meetings
Following are highlights of the Annual Lake Committee Meetings for Lakes Ontario and Superior for 2004. We will report on the Lake Committee of Huron in an upcoming issue; reports Erie and Michigan were reported in the April issue.
upper lake committee meetings — for Lakes Michigan, Huron and Superior— were
held in Ann Arbor, MI, March 22-25. The lake committee meeting for Lakes
Erie, Huron and Ontario was held in Grand Island, NY, March 29-April 1.
Status of Major Prey Fish Stocks
USGS studies, U.S. Waters of Lake Ontario, 2003
Adult alewives (age-2 and older) were somewhat more abundant than in spring 2002. Abundance of age-1 alewives was above the long-term average and similar to that in 2002. Despite two successive years of better than average age-1 abundance, adult alewives increased sharply during summer 2003. Numbers and biomass of age-1 and older rainbow smelt in 2003 were much lower than the record lows recorded during 2000-02. Abundance of slimy sculpins along the south shore at depths >70 m decreased slightly in 2003, and remained well below the 1991 peak. No deepwater sculpins were collected in 2003.
Alewife and rainbow smelt are the most
abundant pelagic planktivores in Lake Ontario, and the most important prey
for salmon and trout. Alewife are also important prey for warm water
predators, notably, walleye, and for cormorants. The abundance of alewife
and smelt has declined over the past decade, likely due to reduced nutrient
loading, proliferation of non-native dreissenid mussels, and the buildup of
stocked salmon and trout predators. Coincident with this decline, threespine
sticklebacks have become more prominent. These recent observations may
signal a change in the pelagic fish community.
In 2003, the number of trawl hauls made for assessment of alewives, rainbow smelt, and slimy sculpins totaled 236. The alewife population can now be indexed more reliably with fewer trawl hauls than in the past because the geographic and bathymetric distribution of alewives narrowed after Dreissena spp. colonized the lake in the early 1990s. Regardless of changes in fish distribution, however, an accurate index still requires a survey not only with wide spatial coverage of U.S. waters but also with seasonal timing that coincides with earlier surveys.
continued on page 2
History and Trends
Predominant prey fish in 2003 included, in order of dominance by biomass, whitefish, herring, bloater, and smelt. These four species represented 58% of the total fish community biomass compared to 70% in 2002, and prey fish biomass has continued to decline since the 1990 peak and is now near the low levels observed in 1978-1979.
Reasons for the decline can be linked to weak recruitment of age-1 herring, bloater, and smelt, as indicated by low densities of these species. Of the less important prey fish, slimy sculpin and ninespine stickleback have continued a long-term trend of decline while trout perch continued to fluctuate at levels above those observed in 1978-1983.
Status and Trends – Lk Superior
continued on page 13
Nominations are open for all offi-cer and director positions of the GLSFC for the ’05-’06 term. Nomi-nations will be accepted via e-mail, fax or snail mail through Aug. 31.
Interested in getting involved? Want to participate in the advocacy process of building and supporting our recreational fishery – and at the same time working more closely with government agencies? Get involved - get nominated.
Voting will again be conducted by First Class mail only. Ballots will be mailed in September, votes counted and results announced in late October.
Send nominations to: Nominating Committee, 630-941-1196-Fax, P.O. Box 297, Elmhurst, IL 60126 - Snail mail, [email protected]. ²
continued from page 1
The abundance of YAO alewife in 2003 was estimated to be 0.123 billion fish, or 2360 metric tons. This is the lowest estimate since the start of the current data series in 1997. The biomass estimate represents only 14% of the average 1997-2002 level, and 19% of the lowest level observed in 1998. The condition of the alewife was also significantly lower than any year since the start of the series, with a typical 120 mm (4.7 in.) (fork length) alewife weighing only 15.1 grams, which is 22% less than the 1997-2002 average.
The extremely low hydroacoustic estimate of YAO alewife abundance appears at odds with observations from bottom trawling surveys conducted earlier in the year, which suggested a slight upturn in the abundance of mature fish
Indices of numbers and biomass of adult alewives in April-May 2003 were 100% and 50% higher, respectively, than those of the previous year. The increase was fueled by strong recruitment of age-2 fish from the 2001 year class. Age-2 fish comprised 28% of the adult catch and age-5 fish, from the record 1998 year class, comprised 39% of the catch. The third most numerous age group was four (25%, 1999 year class).
The abundance index for age-1 alewives (2002 year class) was similar to that of the previous year and about 10% above the long-term mean. Although only a moderately strong cohort, the 2002 year class should have provided sufficient age-2 recruits to maintain adult abundance on an upward trajectory. However, the initial decline was likely from a spring die-off precipitated by the near record low condition of the fish and the decline was perhaps exacerbated during the summer months by predation.
Size of alewife year classes
age-1 is positively linked to nearshore water temperatures during May-July
and negatively linked to the number of
Status of Prey Fish
continued on page 3
? Established 1972 ?
Daniel N. Thomas, Illinois
Robert Mitchell, Michigan
Michael D. Sanger, Wisconsin
Thomas G. Couston, Illinois
Illinois – Robert Gaik
Indiana – Mike Schoonveld
Michigan - Ronald Dubsky
Minnesota - Dave Koneczny
New York – Jay Levy
Ohio - Thomas Mayher
Ontario – Darryl Choronzey
Pennsylvania - Ed Kissell
Wisconsin – Louis Kowieski
Representing a major interest in the aquatic resources of the Great Lakes states and the province of Ontario, the Great Lakes Sport Fishing Council is a confederation of organizations and individuals with a concern for the present and future of sport fishing, our natural resources and the ecosystem in which we live. We encourage the wise use of our resources and a search for the truth about the issues confronting us.
Inland Seas Angler
Great Lakes Basin Report
Dan Thomas, 630/941-1351
Bob Schmidt, 773/283-7871
Robert James, 630/530-7760
Ó Copyright 2002 by Great Lakes Basin Publications, the Inland Seas Anglers-Great Lakes Basin Report is the newsletter of the Great Lakes Sport Fishing Council, a federally recognized not-for-profit 501(c)(3) organization, and recognized for tax-deductible giving by the federal government.
Opinions expressed are those of the authors and not necessarily those of GLSFC, its officers or staff. Reproduction of any material by paid-up members is encouraged, but appropriate credit must be given. Reproduction by others without written permission is prohibited.
Address Change: Please send six weeks in advance with old mailing label to Great Lakes Basin Report, P.O. Box 297, Elmhurst, IL 60126, (630) 941-1351; Fax (630) 941-1196; [email protected]
continued from page 2
days nearshore water is <4º C (39º F) during the first winter after hatch. Year class size is also influenced by the abundance of spawners in a curvilinear manner ― weak year classes are produced by large and small spawning stocks whereas strong year classes are produced by intermediate spawning stocks. In spring 2003, the size of the spawning stock was intermediate. May-July water temperatures, however, were cooler than average indicating unfavorable conditions for reproduction and the duration of winter, although currently uncertain, is apparently going to be longer than average indicating low survival of juvenile alewives.
Prognosis for the Lake Ontario alewife population returning to previous abundance levels is poor. The population apparently was unable to return to the moderate abundance levels of the early 1990s despite the fact that reproductive success was better than average in 2001 and 2002. The process of food web disruption, mediated by exotic species, may well have eroded lower trophic level support for the Lake Ontario alewife population to below that of the early 1990s. With the carrying capacity of the lake reduced, the alewife population at a low level, and environmental conditions unfavorable for production of age-1 alewives, we expect the index of adult alewife abundance to be at, or below, the record low of 1998-1999 through 2005.
The 2003 population estimate of YAO rainbow smelt was 90 million fish or 602 metric tons. This is also the lowest abundance observed since the start of the series in 1997, and represents approximately 23% of the average biomass observed during the recent low-abundance period starting in 1999. The condition of smelt was not assessed in 2003 because only a few fish were caught in the trawls, although visual examination suggested that the condition in 2003 was not obviously different from that in 2001.
The record low hydroacoustic abundance estimate of YAO smelt is consistent with the bottom trawl estimate made earlier in the year, which was the lowest since the start of the bottom trawling program in 1978.
Number and biomass indices of age-1 and older rainbow smelt were lower than in 2000-2002, setting new record lows (numbers=92/tow). Abundance of rainbow smelt has been at or near 26-year lows for four consecutive years with biomass at 10-20% of the long-term average of 4.58 kg (10.1 lb)/tow.
Rainbow smelt year classes generally alternate between strong and weak in Lake Ontario apparently due to cannibalism, primarily by yearling smelt on young-of-year. The catch of yearling rainbow smelt in 2003 was lower than in 2002, thus breaking the alternating pattern in year class strength that had been intact since 1983. Because abundance of yearling rainbow smelt was low in 2003, we would expect to see an increase in yearling abundance in 2004. However, during our trawling survey in autumn 2003, few young-of-year rainbow smelt were observed indicating that should an increase in yearling abundance occur in 2004, it will not be large.
The mean weight of rainbow smelt caught during the June 2003 survey increased to 3.9 g (0.14 oz.) from 3.0 g (0.11 oz.) in June 2002, because yearling rainbow smelt (the youngest age group in the catch) were less abundant in 2003 than in 2002. The heaviest mean weight for rainbow smelt was 13.8 g (0.49 oz.) in 1979. Abundance of large smelt remained low in 2003. Large smelt made up less than 3% of the population during 1989-2002 and in 2003 they made up <1% of the population. The stratified mean catch per tow of large rainbow smelt ranged from 1 to 14 during 1989-2002 and was only 1 in 2003. In contrast, during 1978-1983, large rainbow smelt were 10 to 26% of the population and mean catch per tow ranged from 55 to 205.
Along the south shore of Lake Ontario, from Olcott to Oswego, slimy sculpin numbers at depths >70 m (230 ft.) decreased slightly from 1338 per tow in 2002 to 1277 per tow in 2003. In southeastern Lake Ontario near Oswego, abundance of slimy sculpin showed some evidence of recovering from the 65% drop that occurred between 1991 and 1992. Indeed, catches at a few depths exceeded 4,000 fish, the largest catches of slimy sculpins since 1991.
In 1996, we lost our ability to index the sculpin populations at depths <70 m (230 ft.). In the future, unless we encounter a notable dieoff of Dreissena, we will no longer be able to index slimy sculpins at depths >70 m (230 ft.) with our traditional trawling gear due to the steady expansion of the dreissenid population into deeper water.
We did not capture any deepwater sculpin in 2003 and we did not conduct additional trawling to attempt to capture deepwater sculpin. During 1998-2000, we caught five deepwater sculpin at depths of 110-150 m (361-492 ft.), two while conducting long-term assessment trawling, and three while conducting short-term assessment trawling that targeted deepwater prey fishes in mid lake, along the international boundary. Prior to 1998, the last documented record of a deepwater sculpin being captured in U.S. waters of Lake Ontario was over 50 years ago. ²
2003 NYSDEC Lake Ontario Report
In 1996, anglers fishing Lake Ontario and its tributaries contributed over $75 million to the New York State economy.
In recent years, the Lake Ontario ecosystem has undergone dramatic changes resulting primarily from the introduction of exotic zebra and quagga mussels (Dreissena polymorpha and D. bugensis, respectively). In addition, improve-ents in wastewater treatment have reduced excessive nutrient concen-rations to historic, more natural levels, thereby lowering the productive capacity of the Lake Ontario ecosystem. Surveys conducted by the USGS in 2002 and 2003 documented further deterior-tion in abundance and distribution of the deepwater amphipod, Diporeia. This phenomenon is thought to be directly linked to the continued range expansion of quagga mussels into deeper waters, as is the recent concern regarding potential shifts in the abundance and distribution of the opossum shrimp, Mysis.
The exotic round goby (Neogobius melanostomus) was first documented in the New York waters of Lake Ontario in 2001, and numerous reports now confirm the presence of this species from the Lower Niagara River in the west to the Thousand Islands region of the St. Lawrence River in the east. The first gobies documented in a U.S. fisheries assessment program were collected by the Research Vessel Kaho at 55 m depth off Olcott. Round gobies were documented for the first time in the diets of cormorants from Pigeon and Snake Islands in 2002, and became the dominant prey of Snake Island cormorants in 2003.
Based on spring 2003 bottom trawling, adult alewife abundance was somewhat more abundant than in 2002, however, fish condition was low. A summer 2003 hydroacoustic preyfish survey, however, indicated that alewife numbers had declined dramatically, and alewife condition deteriorated further. While a relatively thin and not fully developed thermocline during the July survey may have biased survey results, a number of independent observations support the hypothesis that alewife numbers declined between spring and summer. First, mean length and weight of age-3 Chinook salmon declined to record low levels in 2003, while Chinook fishing success (catch per hour) reached record high levels.
These observations suggest that the primary prey of Chinook salmon (alewife) was in limited abundance. Alewife condition between spring and fall 2003 improved at a record high rate, indicating fewer alewives competing for food or an abundance of available food. The presence of the exotic zooplankter Bythotrephes (spiny water flea) in alewife stomachs during the fall of 2003 suggests that the former is more likely, as Bythotrephes abundance is typically suppressed through alewife predation.
Coldwater Fisheries Management
· Fish stocking included 1.62 million Chinook salmon, 256,000 coho salmon, 681,000 rainbow trout, 500,000 lake trout, 452,000 brown trout, and 82,000 Atlantic salmon .
· In 2003, 420,000 lake trout and 181,050 brown trout were stocked offshore by military landing craft in a continuing effort to reduce predation on newly stocked fish by cormorants and predatory fish.
· Initial results evaluating the performance of shore-stocked vs. barge-stocked brown trout at Sodus Bay (Salmon River hatchery reared) and Oak Orchard (Caledonia hatchery reared) in 2001 and 2002 suggested that shore-stocked brown trout outperformed barge-stocked fish in both open lake and tributary fisheries, and that nearly nine times more fish returned to the creek from the Oak Orchard stockings,. Due to the larger size of Caledonia Hatchery brown trout relative to Salmon River Hatchery, stocking locations by hatchery were reversed in 2003 to evaluate the influence of size at stocking on post-stocking survival, and this experimental stocking will continue in 2004. Evaluations will continue through 2006.
· Mean lengths of age-1 and age-2 Chinook salmon sampled in the open lake fishery were below average, although the differences in lengths between many years were not statistically significant. Reductions in Chinook salmon growth in 2003 were most evident in age-3 fish. Mean lengths of age-3 fish in 2003 were record lows, and were significantly different from all other years compared (e.g., mean length of age-3 Chinook in August 2003 was 35.57 inches, 1.64 inches and approximately 3.9 lbs less than August 2002).
· Mean weights of age-3 male and female Chinook salmon returning to the Salmon River hatchery in 2003 were at record low levels, as was mean weight of age-1 males (jacks). The predicted weight of a 900 mm (34.5 in.) total length Chinook (15.5 lbs.) increased slightly from the record low observed in 2002. Mean weights of age-2 coho were also low in 2003. Growth of steelhead was intermediate among years sampled, however, they are surveyed in the spring of the year and therefore do not reflect growth during 2003.
· Since the institution of seasonal base flows in the Salmon River, a dramatic increase in natural reproduction of Chinook salmon has been documented. Densities of young-of-year Chinook salmon were markedly lower in 2003, likely due to reduced baseflows resulting from prolonged drought conditions in the fall of 2002.
· A three-year tagging study was initiated in 1999 to address the effects of stocking method on the recent, relatively poor survival of Salmon River stocked Washington steelhead. Considerable differences exist in numbers returned between fish stocked in different years and among fish stocked in a given year returning in different years, and evaluations will continue in 2004.
· 225,000 pre-smolt Chinook salmon and 65,720 rainbow trout were reared by cooperating sportsmen in net pens within Lake Ontario tributaries.
· Evaluations of the performance of steelhead pen-reared at Oswego Harbor are very favorable. To date, 80 coded wire-tagged steelhead have been collected from the Oswego River, Salmon River, and the open-lake fishery. Sixty-eight of the 80 returns were pen-reared fish. Also, there was no significant difference between stocking method (pen-reared vs. direct stocked) and return location (open lake, Salmon River, Oswego River).
· Separate lots of marked Chinook salmon from the Salmon River and Caledonia Hatcheries (40,000 each) were stocked into the Lower Niagara River (2000 and 2002) and Oak Orchard Creek (1999 and 2001) to assess differential effects of hatchery origin and pen rearing vs. traditional stocking on performance in the fishery.
Returns of the 1999 year class stocked at Oak Orchard in 2001 and 2002 suggest that pen-reared Salmon River Hatchery origin Chinook returned the greatest yield to Oak Orchard Creek. Direct-stocked Caledonia fish returned at an intermediate level, and direct-stocked Salmon River fish returned the poorest. Returns of the 2000 and 2002 year classes stocked at the Niagara River are in contrast with the Oak Orchard study. Returns to the stocking site from the 2000 stocking slightly favor the Salmon River direct stocked fish over the pen reared fish. The Caledonia direct stocked fish returned the poorest.
With only age-1 returns from the 2002 stocking available, the pattern of pen reared fish and direct stocked Salmon River fish returning better than the direct stocked Caledonia fish is similar to that observed with the 2000 year class. Evaluations will continue through 2005.
Catch of age-2 lake trout in 2003 declined, and was the third lowest on record. Trends in numbers of age-2 lake trout caught in trawls and age-3 fish caught in gill nets for the 1975 to 1995 year classes suggested that recruitment of hatchery fish to the population was governed by survival during their first year after stocking. Subsequent to the 1995 year class, this relationship has deteriorated, suggesting increased mortality of stocked lake trout during their second year in the lake.
· A total of 702 adult lake trout were captured in the September 2003 gill net survey. Catch rates for mature lake trout remained remarkably stable from 1986 to 1998. The catch per unit of effort (CPUE) of mature fish, however, declined by 30% between 1998 and 1999. Poor survival of hatchery fish was likely responsible for declining abundance of immature lake trout since 1989 and current declines in adult numbers. The CPUE for mature lake trout in 2003 increased, but was 34% below the 1986-1998 average.
· Accurate calculation of the average age of mature, female lake trout is no longer possible due to a lack of funding for coded-wire tags. Average age of mature female lake trout has been increasing steadily since the mid 1980s. The average age of 9.55 years in 2001 reflects a population comprised of the oldest group of mature females since the rehabilitation program was initiated.
· In 2003, a total of 6 naturally produced lake trout (108 to 404 mm or 4.25 to 16 in. total length) were caught with bottom trawls. Survival of naturally produced lake trout to the fingerling stage in summer and fall occurred each year during 1993-2002. Further, survival to older ages has also been apparent. The distribution of catches of wild fish suggests that lake trout are reproducing throughout New York waters.
· The estimated annual harvest of lake trout since the slot limit (635 – 762 mm or 25 to 30 in.) was reinstated in 1992 has been more than 4 times lower than previous years when no size limits were in effect. Harvest reached its lowest recorded level in 2003 with an estimated 4,711 lake trout harvested. The percentage of lake trout harvested by anglers that were of trophy size (>762 mm or >30 in.) reached a record high 48.5% in 2003.
· A study evaluating the effect of location (onshore vs. offshore) and timing (May vs. June) of stocking on the survival of lake trout is being conducted at Olcott and Sodus, New York. Preliminary results suggest that offshore stocking substantially enhances catches of stocked, age-1 lake trout in bottom trawl surveys, however, catches at older ages indicate that stocking method affects distribution of fish as well as survival. Although early catches of experimental fish were encouraging, the returns at age-2 and older remain insufficient to discern with certainty which, if any, stocking method conveys the best survivorship.
· 211,480 fingerling walleye were stocked into Lake Ontario embayments and the Lower Niagara River.
· Total catch of warmwater fish in the 2003 Eastern Basin gill netting program increased slightly for the second year since the record low levels observed in 2001, as did smallmouth bass abundance. Three year moving average catches for walleye, yellow perch, and pumpkinseed are increasing, whereas the same for smallmouth bass is relatively stable. Growth of smallmouth bass has increased in recent years. Lake sturgeon have been collected in seven of the last nine years, suggesting improvement in population status.
· Index gill netting in the Thousand Islands region of the St. Lawrence River revealed continued low abundance of smallmouth bass and northern pike.
· Yellow perch abundance in Lake St. Lawrence index gill netting remained fairly stable in 2003. Smallmouth bass abundance fell below the long-term average. Walleye abundance decreased 27% from 2003, but remains above the long-term average.
· Total trout and salmon fishing success (catch rate per hour) reached record high levels in 2003 for both charter and non-charter boats.
· Total fishing boat trips, and trips targeting trout and salmon, have declined significantly since the 1990 peak. Largest declines in effort occurred between the 1990-91 seasons and the 1991-92 seasons, before reductions in the Lake Ontario stocking program were discussed.
· In 2003, total effort was estimated at 79,958 fishing boat trips, a record low among the 19 years surveyed. Total fishing boat effort in 2003 was down 15.8% compared to the 1998-2002 boat trip average, and down 63.3% compared to the 1990 peak.
· An estimated 47,874 boat trips targeted trout and salmon in 2003, a record low effort estimate for trout and salmon anglers among the years censused. Trout and salmon fishing effort in 2003 was down 22.6% compared to its 1998-2002 average, and down 74.0% compared to the 1990 peak year.
· The number of lampreys observed per 1,000 trout and salmon caught was estimated at 23.98 in 2003, a 96.8% increase compared to the 1998-2002 average, and the highest value observed among the 18 years that sea lamprey observations have been specifically asked for.
· Trips targeting smallmouth bass during the open season show a variable but statistically significant upward trend over the years censused, averaging 3.4% per year. An estimated 27,754 boat trips targeted smallmouth bass abundance in the Eastern Basin as measured in index gill nets remains low. In addition, harvest rates of smallmouth bass in the Eastern Basin remain below the lakewide average. Smallmouth bass in 2003, the 5th highest estimate for bass anglers, but a 0.9% decrease compared to the 1998-2002 average bass effort.
· Data on smallmouth bass fishing in Lake Ontario collected from the 1985-2003 censuses were analyzed in more detail as part of the evaluation of the impacts of double-crested cormorant predation on fisheries. From 1985-90, harvest rates at Henderson Harbor were nearly equal to or greater than the lakewide average harvest rates and averaged 1.16 smallmouth bass harvested/ angler hour. From 1991-2003, smallmouth bass harvest rates at Henderson Harbor, adjacent to the Little Gallo Island cormorant colony, were all below the lakewide average. The Henderson Harbor site continues to be the only localized bass fishery that has experienced a decline in harvest rate.
· A creel census directed at characterizing steelhead angler effort and success in the Salmon River estimated 6,183 angler days in 2003, the lowest level of effort recorded since the survey began in 1997. High water conditions during the survey period likely contributed to the reduced effort.
· A creel census was conducted in 1998 in the Eastern Basin of Lake Ontario as part of an overall study to assess impacts of double-crested cormorants on sportfish populations. This census was repeated in 2003, and indicated a 40.1% reduction in angler effort relative to 1998. While the targeted smallmouth bass harvest rate in 2003 was unchanged from 1998, the 2003 catch rate was substantially lower.
Diets of Double-crested Cormorants and Impacts on Sportfish Populations
· For the fifth consecutive year, cormorant population control was continued through oiling of eggs with food grade vegetable oil at the Little Galloo Island colony.
· Round gobies were first documented in the diets of cormorants from Snake and Pigeon Islands in 2002, and gobies dominated the diets of Snake Island cormorants in 2003.
· Estimated consumption of smallmouth bass by cormorant colony (Lake Ontario only) in 2003 was: Little Galloo Island – 500,000, Pigeon Island – 10,000, and Snake Island – 110,000.
· Estimated consumption of yellow perch by colony (Lake Ontario only) in 2003 was: Little Galloo Island – 4.25 million, Pigeon Island – 160,000, and Snake Island – 2.34 million.
· Egg oiling on Little Galloo Island reduced cormorant chick production by approximately 98%, thereby reducing the number of cormorant feeding days by 690,000. The resulting reduction in fish consumption was estimated at 340,000 smallmouth bass and 1.19 million yellow perch.
· Smallmouth bass abundance in the Eastern Basin as measured in index gill nets remains low. In addition, harvest rates of smallmouth bass in the Eastern Basin remain below the lakewide average.
· Modeling suggests that an overall reduction in cormorant numbers within the eastern basin can be expected as a result of egg oiling on Little Galloo Island. To reach the objective of 15,00 nesting pairs of cormorants, oiling of all nests on Little Galloo island would need to occur through 2008. A less intensive maintenance program would begin in 2009. Residual effects would carry into the year 2010, at which time the target population of 1,500 pairs would be achieved. From 2010 on, the eastern basin cormorant population would be predicted to again increase slowly if Canadian colonies continued to grow. Cormorant populations have continued to grow on Lake Ontario over the past several years with the exception of 2003, but less predictably than in the 1980s and early 1990s.
· Estimated fish consumption by cormorants from three upper St. Lawrence River colonies (Ontario waters) in 2003 (6.35 million fish) was within the range (4.79 to 6.64 million) reported for the four previous years. Average annual fish consumption by cormorants from Griswold, McNair, and Strachan Islands since 1999 is 5.97 million fish. Total, combined cyprinids, 520,000 pumpkinseeds, and 40,000 smallmouth bass.
Highlights of the 2003 Lake Ontario Fishing Boat Census
Fishing Boat Effort
· Total fishing boat trips, and trips targeted at trout and salmon, have declined significantly since the 1990 peak. Largest declines in effort occurred between the 1990-91 seasons and the 1991-92 seasons, before reductions in the Lake Ontario stocking program were even discussed.
· In 2003, total effort was estimated at 79,958 fishing boat trips, a record low among the 19 years surveyed. Total fishing boat effort in 2003 was down 15,8% compared to the 1998-2002 boat trip average, and down 63.3% compared to the 1990 peak. The largest reductions in yearly percent contributions have occurred in the months of April and May, and in the west and west/central areas.
· An estimated 47,873 boat trips targeted trout and salmon in 2003 (59.9% of total trips), a record low effort estimate for trout and salmon anglers among the years censused. Trout and salmon fishing effort in 2003 was down 22.6% compared to its 1998-2002 average, and down 74.0% compared to the 1990 peak year. The largest reductions in yearly percent contribution among trout and salmon anglers have occurred in the month of April and in the west/central area.
· Trips targeted at smallmouth bass during the open season show a variable but statistically significant upward trend over the years censused, averaging 3.4% per year. An estimated 27,754 boat trips targeted at smallmouth bass in 2003 (34.7% of total trips), the 5th highest estimate for bass anglers, but a 0.9% decrease compared to the 1998-2002 average bass effort. Effort targeted at smallmouth bass has always been highest in the east/central and east areas, averaging 46.0% and 26.2%, respectively, over the years censused.
· Excursions by non-fishing power boats were estimated at just 87,783 in 2003, the third lowest estimate among the years censused, and down 53.9% from the peak observed in 1988. Excursions by sail boats were estimated at just 17,872 in 2003, the lowest among the years censused, and down 63.0% from the peak observed in 1987.
Charter Boat Trips
· The number of charter fishing boat trips peaked between 1988 and 1991, and then declined to a low of just 8,790 boat trips in 2003, similar to the pattern described for total fishing boat trips and trips targeting trout and salmon.
· The relative importance of charter boats to the fishery has shown a pattern of increase over the years censused, and in 2003 charter boats contributed 11.0% of the total fishing boat trips. Since charter boats typically carry more anglers, fish for a longer period of time, have higher harvest rates, and harvest a higher percent of the fish caught, their significance is even greater when using other statistics. In 2003, charter fishing boats contributed 20.6% of the total boat angler trips, 29.9% of the total boat angler hours, and harvested 55.5% of all trout and salmon kept within the area censused. By species, charter boats harvested 67.3% of the lake trout kept in 2003, 60.3% of coho salmon, 59.0% of rainbow trout, 58.6% of brown trout, and 50.0% of Chinook salmon.
2003 Harvest and Catch Summary:
Chinook Salmon – Chinook salmon was the most commonly harvested salmonine in 2003 (43.9% of total) with an estimate of 31,525 fish, a 72.2% increase compared to the 2002 Chinook harvest, and a 24.2% increase compared to the 1998-2002 average harvest.
Brown Trout – Brown trout was the 2nd most commonly harvested salmonine in 2003 (31.0% of total) with an estimate of 22,277 fish, a 32.5% increase compared to the 2002 brown trout harvest, but a 6.8% decrease compared to the 1998-2002 average harvest.
The 2003 seasonal harvest rate among boats seeking trout and salmon was 0.457 brown trout per boat trip, the 3rd highest seasonal harvest rate among the years censused, and a 20.1% increase compared to the 1998-2002 average rate. Brown trout harvest rates in 2003 were above their respective 1998-2002 averages for the months of April and July-September, and in the west and east/central areas.
Rainbow Trout – Rainbow trout was the 3rd most commonly harvested salmonine in 2003 (11.5% of total) with an estimate of 8,245 fish. This represents a 20.1% increase compared to 2002, but still the 2nd lowest harvest estimate among the years censused.
Coho Salmon – Following a record low in 2002, coho salmon harvest rebounded in 2003, with a modest estimate of 5,079 fish. The 2003 seasonal harvest rate among boats seeking trout and salmon was 0.106 fish per boat trip, similar to the average harvest rates of previous years. Compared to their respective 1998-2002 averages, 2003 harvest rates were substantially lower in the months of April and August, but substantially higher in the month of September. Coho salmon was the 4th most commonly harvested salmonine in 2003 (7.1% of total) with an estimate of 5,079 fish. As in all previous years, the 2003 coho salmon harvest was dominated by age-2 fish.
Lake Trout – Lake trout was the 5th most commonly harvested salmonine in 2003 (6.6% of total) with a record low estimate of just 4,711 fish (58.7% decrease compared to the 1998-2002 average harvest). The 2003 seasonal harvest rate among boats seeking trout and salmon was 0.098 lake trout per boat trip, the lowest seasonal harvest rate among the years censused, and a 47.8% decrease compared to the 1998-2002 average harvest rate. Harvest rates in 2003 were below their respective 1998-2002 averages.
Total Trout & Salmon – A total of 71,854 trout and salmon were harvested in 2003 within the area censused. This is a 20.3% increase compared to the record low recorded in 2002, but a 14.7% decrease compared to the 1998-2002 average harvest. The 2003 seasonal harvest rate among boats seeking trout and salmon was 1.491 trout and salmon per boat trip, up 32.1% compared to the 2002 harvest rate, and up 10.5% compared to the 1998-2002 average harvest rate. Since poor harvest in one species is often offset by higher harvest in another, the total trout and salmon harvest rates were more consistent between months and areas.
Among charter boats, the 2003 harvest rate was 4.813 trout and salmon per boat trip, up 13.3% compared to the 1998-2002 average. Aggregate 3-fish limits of coho-chinook-rainbow-brown for the party were harvested on 16.5% of the charter boats in 2003. Lake trout 3-fish limits for the party were harvested on only 0.6% of the charter boats.
Among noncharter boats, the 2003 harvest rate was 0.795 per boat trip, up just 5.6% compared to the 1998-2002 average. Aggregate 3-fish limits of coho-chinook-rainbow-brown for each angler were harvested on only 1.7% of the noncharter boats in 2003, while lake trout 3-fish limits were harvested on only 0.1% of the noncharter boats.
Smallmouth Bass – Smallmouth bass has been the most commonly harvested species in recent years (42.9% of the total in 2003). An estimated 65,633 were harvested in 2003, only 1.7% higher than the 1998-2002 average harvest.
Smallmouth bass catch and catch rates are very impressive, and both have increased in recent years. An estimated 405-723 smallmouth bass were caught within the area censused in 2003, the 4th highest catch among the years censused, and 2.0% higher than the 1998-2002 average. The smallmouth bass catch rate among boat anglers targeting smallmouth bass in 2003 was 13.7 fish per boat trip. This was the 2nd highest seasonal catch rate among the years censused, and 7.5% above the 1998-2002 average.
The Henderson site (Stony Creek and Association Island Cut) was the only localized smallmouth bass fishery along New York’s Lake Ontario shoreline, which shows a downward trend in harvest rate ratios in recent years. Since 1991, Henderson harvest rates have been consistently lower than the lakewide rates (13-year average ratio 0.72). The timing corresponds with the period when relative mortality of young smallmouth bass increased significantly in the eastern basin of Lake Ontario, presumably in response to predation by double-crested cormorant.
Yellow Perch and Walleye – An estimated 8,171 yellow perch were harvested in 2003; a 77.8% increase compared to 2002, but a 2.5% decrease compared to the 1998-2002 average harvest. Walleye harvest in 2003 was estimated at 560 fish; a 28.6% decrease compared to the 1998-2002 average harvest.
Lake Sturgeon Stocking Summary, 2001-2003
No sturgeon were stocked in 2001 or 2002. Egg mortality claimed the entire 2001 year class, possibly due to bacterial contamination. Egg collection protocol now includes prophylactic decontamination on site with Erythromycin Phosphate prior to transport to the hatchery.
In 2002, mechanical failures in the adult lake sturgeon holding system resulted in termination of adult collection. In 2003, adult sturgeon were captured over a three day period from 28-30 May, with 45 sturgeon captured.
Three of 7 fish identified as females were kept for egg take. All females retained were relatively large from the perspective of this project history (24-28 kg). A total of 9 males, ranging from 12-20 kg, were kept as sperm donors.
Two females contributed approximately 33,000 eggs, which were fertilized and distributed between the NYSDEC Oneida Fish Culture Station, the USFWS Pittsford National Fish Hatchery (Vermont), and three research facilities. One hundred percent mortality was reported for eggs and larvae from female #13 during the first 7 days post fertilization.
Total fingerling production for 2003 was 2,572. A single female (#18) was the sole provider of progeny despite efforts to increase genetic variability of stocked fish. ²
2003 Ontario Fisheries of Lake Ontario
Status of Major Species
Catch rates in the boat angling fishery indicated that Chinook salmon abundance in Lake Ontario has been relatively stable from 1988 to 2003, despite stocking reductions in 1993. Natural reproduction after 1995 and density dependent survival of young Chinook salmon may have contributed to these steady catch rates. Growth (in length) remains good, but observed drastic declines in the weight of spawning females in the Credit River run are cause for concern.
Counts of rainbow trout at the Ganaraska River fishway remain low. This may indicate that adult returns to other Ontario tributaries are low, too. The long-term harvest rates of rainbow trout from the boat fishery in Lake Ontario reflect the counts at the Ganaraska Fishway, since wild rainbow trout are a significant component of the population. Recent year-to-year variation in rainbow trout harvest rates appears to be related to spring temperature. The low rainbow trout harvest rate in 2003 was consistent with the average air temperature in April 2003, which was the lowest in at least 20 years. Condition of rainbow trout in the Ganaraska River in 2003 was similar to the long-term average. These fish were sampled during spring, and their condition reflected growth in Lake Ontario in 2002.
The decline in abundance of mature lake trout appeared to continue in 2003, although past changes in strains and geographical patterns of stocking make unbiased assessment of the status of the lake trout population difficult. Survival of young stocked fish has stabilized in the recent past after a period of decrease, and this should lead to a stable albeit low adult population. The condition of large lake trout continued to decline, and lamprey wounding remained at low levels.
Adult lake whitefish abundance remains low with little new recruitment. Summer distribution of adult fish, as indicated by assessment gillnets, appears to have contracted to a relatively small area in the vicinity of Point Traverse. Reproduction was successful in 2003 after five consecutive very poor year-classes; this 2003 year-class will be monitored closely in the years ahead in terms of distribution, growth and survival. The commercial harvest of lake whitefish has declined significantly in recent years.
The numbers of eel migrating upstream at the ladder, located at the R.H. Saunders Hydroelectric Dam on the St. Lawrence River, remain at a very low level. Commercial harvest of eel below the dam (Quota Zone 1-7) remains relatively stable; however, harvest above the dam (all other quota zones) has declined in an unprecedented fashion. The low upstream migration suggests that the commercial harvest of eel in the upper St. Lawrence River and Lake Ontario will remain low for at least the next decade. Ontario is continuing to work with the local commercial fishery and with management agencies from other jurisdictions to address the decline in eel abundance. Sustainable management practices throughout the range of this species (Labrador to the Caribbean) will be required to restore eel abundance.
The eastern Lake Ontario smallmouth bass population remains at low but stable abundance. In the Bay of Quinte the abundance is low, declining further in 2003. The current low abundance levels in eastern Lake Ontario and the Bay of Quinte are not consistent with recent mid-summer water temperatures; mid-summer water temperatures had been driving smallmouth bass abundance prior to the mid-1990s. In the St. Lawrence River (Thousand Islands), smallmouth bass abundance increased in 2003 and approached levels observed in the early-1990s.
Largemouth bass have increased in recent years in the Bay of Quinte; their abundance now rivals that of walleye in littoral zone areas during summer. A recreational fishery (including increased tournament angling) targeting largemouth bass has developed over the last several years.
Yellow perch abundance in eastern Lake Ontario and in the Thousand Island area of the St. Lawrence River remains low but stable. In the Bay of Quinte, abundance remains high but is in decline. The commercial harvest of yellow perch has declined since the late-1990s.
Walleye remain the most important species for recreational fisheries and are valued by the First Nation's fishery and non-native commercial fishery in eastern Lake Ontario. Currently, the population comprised of fish age-3 and older appears to be in a relatively steady state, with numbers hovering around 400,000 fish. Reproduction appears to have improved slightly—the strongest two year-classes since 1995 occurred in the last three years. Age-2 fish represented the bulk of the recreational fishery in 2003. This 2001 year-class should cause the age-3 and older population to increase in 2004. Simulations suggest that given the most recent reproduction observations and the current level of mortality from all sources, the age-3 and older walleye population will remain at about 400,000 fish until 2006.
Whole-lake hydroacoustic assessment of the two principal prey fish species in Lake Ontario, alewife and smelt, suggested record low population levels in 2003. The abundance estimates of yearling-and older fish of both species were approximately one-fifth of the average levels observed in recent years. Furthermore, the body condition of alewives was also the lowest observed in the recent years.
Data from index bottom trawling program suggests that in 2003 the round goby has completed its spread throughout the Bay of Quinte, and may be reaching abundances that are comparable to those of all other species combined at some locations in the lower bay. Gobies have also been reported in western Lake Ontario since the late-1990s. Their presence in other areas is poorly documented, but absence of reports from the Canadian side of central Lake Ontario suggests that this area remained free of gobies in 2003.
Hydroacoustic Assessment of Prey Fish
The 2003 survey consisted of five shore-to-shore north-south transects in the main lake, and one U-shaped transect in the Kingston basin. The 2003 population estimate of yearling-and-older (YAO) alewife was 123 million fish or 2360 metric tons. This is the lowest abundance since the start of the current data series in 1997, and the biomass only 14% of the 1997-2002 average level. The condition of the alewife was significantly poorer than in any year since 1997.
The 2003 population estimate of YAO rainbow smelt was 90 million fish or 602 metric tons. This is also the lowest abundance observed since 1997, and represents approximately 23% of the average biomass observed during the recent low abundance period starting in 1999. The condition of smelt was not assessed in 2003 due to insufficient sample size.
Threespine sticklebacks are not currently assessed from the acoustic data, but midwater trawls conducted during the hydroacoustic surveys provide some information on their population trends. In 2003 the catches of threespine sticklebacks were among the lowest since the mid 1990s when this species came into prominence.
St. Lawrence River Fish Community
The overall catch from 48 gillnet sets in the 2003 Thousand Islands project was 1,574 fish comprising 20 species. The average number of fish captured per net set during 2003 (39.9 fish per net, both netting types combined) was higher than was observed in the 2001 survey, however the numbers of fish remain lower than those observed during the late 1980s. As was the case in 2001, average catches were higher in mono-filament nets than in multi-filament nets. For this reason, a correction factor of 1.58 was applied. See the 2001 annual report for discussion of the statistical treatment of the two net types.
Yellow Perch – Yellow perch continue to be the most abundant fish captured in the Thousand Islands gillnet program. The total catch in 2003 increased from 2001 levels. Age analysis of fish sampled during the 2003 netting program estimated the average age of the yellow perch community to be 3.5 years.
Centrarchids – Six centrarchid species were captured in the netting program: rock bass, pumpkinseed, bluegill, smallmouth bass, largemouth bass and black crappie. Rock bass catches were lower in 2003 than 2001, yet still very high relative to other species. Pumpkinseed and smallmouth bass populations appear to have followed similar trends until 2003, where smallmouth numbers increased and pumpkinseed declined slightly. Smallmouth bass catches increased in 2003 to levels previously seen in the early-1990s. Strong age-1 and age-4 age groups were likely responsible for the upward smallmouth bass abundance trend observed in 2003. Although catches of pumpkinseed increased during 1999, they resumed their overall declining trend in 2001 and 2003.
Northern Pike – For the first time since 1989, the catch of northern pike increased. A decline in northern pike catches through the 1990s has also been reported over the same time period in the New York waters of the Thousand Islands, with weak fluctuations since 1997.
Sea Lamprey Management in Lake Ontario
Lampreys Observed – 3,370 lam-preys were estimated attached to angler caught trout and salmon within the area censused in 2003, up 100.4% compared to the 1998-2002 average, and the highest yearly number estimated since 1990. Wounding rates in Lake Ontario have been remarkably stable during 1985-2003, ranging from 1-3 marks per 100 fish.
During 1983-2003, the USFWS (Service) and Dept. of Fisheries and Oceans (Department) annually have trapped spawning-phase sea lampreys in an average of 15 tributaries, and have estimated lakewide abundance of spawning. Estimated lakewide abundance averaged 72,000 during 1981-1990, and was reduced to an average of 33,000 during 1991-2000. During 1984-2003, abundance of spawners has shown a significant negative linear trend.
· Lake Ontario has 659 tributaries (405 Canada, 254 U.S.).
· 59 tributaries (30 Canada, 29 U.S.) have historical records of production of sea lamprey larvae.
· 43 tributaries (22 Canada, 21 U.S.) have been treated with lampricide at least once during 1994-2003.
· Of these, 29 tributaries (13 Canada, 16 U.S.) are treated on a regular cycle.
· Treatments were completed in 13 tributaries (7 Canada, 6 U.S.) scheduled for treatment.
· South Sandy Creek, treated in 2002, was added to the stream treatment list after a quantitative assessment was conducted in 2003.
· The treatment of Duffins Creek was conducted from above the sea lamprey barrier due to the presence of larvae in this portion of the stream. Adult sea lampreys were observed above the barrier during the treatment.
· A new seasonal stop log sea lamprey barrier was constructed in Wesleyville Creek during 2003 under a partnership agree-ment between Ontario power Generation, Ganaraska Conserva-tion Authority and the Great Lakes Fishery Commission.
· Feasibility studies, detailed design, and tendering for remedial works on an existing dam on the Credit River were completed. Negotiations regarding property agreements with the dam owner delayed construction, which is now scheduled for summer 2004.
· A new construction project is being developed for Bronte Creek.
· Presently, 13 streams have sea lamprey barriers or components of barriers that are operated and maintained by agent staff. ²
MNR Recreational Fishery Surveys
During 2003, Chinook salmon dominated the catch and harvest in the boat angler fishery in Ontario's waters of Lake Ontario, followed by rainbow trout. Together they represented over 90% of the catch and harvest. Declines in catch over the past decade have paralleled a decline in effort. The effort of launch daily anglers and all boat anglers was estimated at 190,015 and 346,766 angler-hours, respectively. This is the lowest effort in all of the years surveyed since 1977, and continues a long-term gradual decline.
Catch rates for the time series from 1977 to 2003 show major shifts in the salmon and trout population in Lake Ontario. Coho salmon was the dominant salmonid in Lake Ontario during the 1970s. Catch rates of rainbow trout and Chinook salmon increased as more were stocked in the 1980s.
Growth of Chinook salmon declined slightly however, 2 year-olds and 3 year-olds were just 10 mm and 16 mm smaller, respectively, than the long-term average length at age.
The commercial harvest comes primarily from the Canadian waters of Lake Ontario east of Brighton (including the Bay of Quinte) and the St. Lawrence River. Commercial harvest statistics for 2003 were compiled from daily catch report (DCR) records managed by the Ministry of Natural Resources in partnership with the Ontario Commercial Fisheries Association (OCFA).
The total harvest of all species was 447,643 lb. ($324,320) in 2003, and has declined 65% since 1996. The majority of this decline can be accounted for by a decline in whitefish harvest (see below). The top five species in terms of landed value in 2003 were yellow perch, whitefish, brown bullhead, sunfish and eel; compared to lake whitefish, yellow perch, eel, brown bullhead and walleye in 1994.
Eel –Eel harvest was 7,452 lb., 8% of the quota. Eel harvest has declined dramatically in the last decade, while the value (price per lb.) has increased.
Yellow perch – Yellow perch harvest was 99,919 lb., 22% of the quota. Yellow perch harvest had increased significantly from 1996 to 1999 but declined by over 60% between 1999 and 2003.
Walleye – Walleye harvest was 6,063 lb., 12% of the quota. The walleye harvest was the lowest it has been since commercial fishing for this species was reestablished in 1989.
Other species – Commercial harvest of brown bullhead, sunfish, black crappie, freshwater drum and suckers declined in 2003, while that of white perch and rock bass increased.
St. Lawrence River
The total harvest of all species was 211,255 lb. ($203,710), and has declined 44% since 1998. The top three species in terms of landed value were yellow perch, eel, and brown bullhead compared to eel, yellow perch, and brown bullhead in 1994.
Eel – Eel harvest was 21,693 lb., 47% of the quota. Of note, 58% of the total eel harvest from Lake Ontario and the St. Lawrence River was taken in Quota Zone 1-7. This quota zone has only 23% of the total quota.
Yellow perch – Yellow perch harvest was 54,148 lb., 35% of the quota.
Other species – Commercial harvest of black crappie, sunfish and brown bullhead declined in 2003.
Lake Whitefish Commercial Catch
Sampling of commercially harvested lake whitefish for biological attribute information occurs annually. In 2003, biological sampling took place to obtain samples for a lake whitefish bioenergetics study. In total, fork length was measured for 5,134 fish and age was interpreted (otoliths) for 414 fish.
Lake Ontario – Mean fork length and age were 490 mm and 10.8 years, respectively. Fish ranged from age-7 to age-17 years. Age-11 (1992 year-class) fish were the most abundant. Fish age-8 to 12 comprised over 90% of the harvest. Mean age of the commercial lake whitefish harvest increased steadily after 1995 as the strong 1991 and 1992 year-classes “moved through” the fishery, and as age-at-first recruitment to the fishery increased over the same time-period.
Bay of Quinte – Mean fork length and age were 488 mm and 10.6 years, respectively. Fish ranged from age-4 to age-20 years. Age-12 fish were the most abundant. This represents the 10th consecutive year that the 1991 year-class was the most numerous year class in Quota Zone 1-3 commercial harvest. Age-8 and age-9 fish also figured prominently in the harvest. As for Lake Ontario, mean age of the commercial lake whitefish harvest in the Bay of Quinte increased steadily after 1995 as the 1991 year-class “moved through” the fishery, and as age at first recruitment to the fishery increased over the same time-period.
This is the first time an enforcement update has been included in the Lake Ontario Management Unit Annual Report. The enforcement program consists of six full-time staff positions, with an Enforcement Supervisor and three Conservation Officers (COs) based out of Glenora. Two other Conservation Officers are based out of Darlington Provincial Park in Bowmanville.
The Glenora COs are primarily responsible for commercial fish management and enforcement, sport fish enforcement, and other enforcement duties as required. Commercial fish management involves the issuance and maintenance of approximately 175 commercial fishing licences for Eastern Lake Ontario, Western Lake Ontario, the Bay of Quinte and some Inland Lakes and waters. Commercial fish duties also include inspecting commercial fish documents from both fishers and local wholesalers to ensure compliance with seasons, quotas, size limits and compliance with legislation governing the purchase and sale of commercial fish.
Darlington COs are primarily responsible for the management and enforcement of commercial fish wholesale and retail outlets in the Greater Toronto Area. The Officers inspect documents from both retail and wholesale outlets to ensure compliance with the Fish and Wildlife Conservation Act and O. Reg 664 as they relate to the purchase and sale of fish.
All Lake COs are responsible for Sport Fish Enforcement on Lake Ontario from Cornwall to the Niagara River. The Lake Ontario Management Unit Enforcement Section usually enters into an agreement with Kemptville District to cover the sport fish enforcement on the St. Lawrence River.
In 2003, the Lake Ontario Enforcement Program entered into joint forces work with Fisheries Officers from the Federal Department of Fisheries and Oceans (DFO). The joint forces work included vessel patrols, market inspections, and intelligence and investigative work. The joint forces work provides a training opportunity to DFO Fisheries Officers and provides additional manpower to MNR. The joint forces work will continue into 2004.
Other enforcement duties for Lake Unit COs involve supporting Provincial enforcement initiatives, assisting other Districts / Lake Units and enforcement of ancillary legislation such as the Off Road Vehicles Act, the Motorized Snow Vehicle Act, etc. In future years this update will include enforcement statistics.
MNR Stocking Lake Ontario
In 2003, OMNR stocked about 1.8 million salmon and trout into Lake Ontario. Just over 500,000 Chinook salmon spring fingerlings were stocked at various locations to provide put-grow-and take fishing opportunities.
About 20,000 Chinook salmon were held in pens at two embayment sites in eastern Lake Ontario for a short period of time prior to stocking. This project was done in partnership with a local community group to determine whether these fish would successfully imprint on the embayments. It is hoped that pen-imprinting will help improve returns of mature adults to this area in the fall, thereby enhancing local nearshore fishing opportunities. Follow-up monitoring is planned.
About 95,000 coho salmon yearlings were stocked into the Credit River. A poor run of coho in the fall of 2002 resulted in a shortfall of 55,000 fish this year.
OMNR stocked about 112,000 Atlantic salmon spring fingerlings and 84,000 fall fingerlings, in support of an ongoing program to restore self sustaining populations of this native species to the Lake Ontario watershed. Partners stocked out about 39,000 Atlantic salmon eggs in incubation boxes, as well as about 15,000 fry.
About 410,000 lake trout yearlings were also stocked. Lake trout stocking is focused in eastern Lake Ontario where most of the historic spawning shoals are found.
About 146,000 rainbow trout yearlings were stocked by OMNR. In addition, local community groups reared about 186,000 rainbow trout fry and 31,000 fall fingerlings. About 181,000 brown trout yearlings were stocked at various locations to provide shore and boat fishing opportunities.
New York State DEC also stocked 3.6 million salmon and trout into Lake Ontario in 2003.
The numbers of eel migrating upstream at the ladder, located at the R.H. Saunders Hydroelectric Dam, remain at a very low level. Commercial harvest of eel below the dam remains relatively stable; however harvests above the dam (upper St. Lawrence River and Lake Ontario) have declined in an unprecedented fashion. The low levels of upstream eel migration suggest that the commercial harvest of eel in the upper St. Lawrence River and Lake Ontario will remain low for at least the next decade.
Actions taken by the Lake Ontario Management Unit to address the declining abundance of eel include:
1) no new commercial licenses issued;
2) commercial quotas for eel reduced by 50% in 2001 and 50% more in 2002;
3) continued operation of the eel ladder at the Saunders Hydroelectric Dam;
4) development of a management plan for American eel in Canadian waters in cooperation with DFO and the Province of Quebec;
5) contributed to the American Fisheries Society eel symposium held during August 2003.²
Status and Trends – Lk Superior
continued from page 1
There continues to be sharp differences in biomass of prey fish populations among jurisdictions. The greatest concentrations of biomass of herring, bloater, smelt and lake whitefish were observed in Wisconsin waters. Prior to 2001, the greatest biomass of bloater was taken in Michigan waters, however, sharp declines in Michigan bloater populations coupled with increases in Wisconsin waters has shifted the area of concentration.
Biomass of prey fishes in Minnesota waters continues to be the lowest among U.S. jurisdictions. Trends in prey fish biomass in Canadian waters followed patterns and levels for U.S. waters and biomass for herring, bloater, whitefish, smelt was substantially greater in western Ontario waters. However, biomass in Canadian waters continues to remain at near record low levels in 2003. Overall, trends in Lake Superior prey fish populations are of continuing decline since the mid-1990s. The 1998 cohorts of herring and bloater produced moderate year classes in 2002, and if another is produced in 2003, prey fish biomass may increase in subsequent years over the present relatively low levels.
During the 26 years of monitoring, strong year-classes occurred during only three intervals, 1984, 1988-1990, and 1998. Most of the adult herring population present in the lake is the result of growth and recruitment of the 1998 year-class. The new, moderate 2002 year class was produced by the 1998 cohort. Lake herring mean biomass in U.S. waters during 1978-2002 was higher than any other species captured, accounting for 22% of the total community biomass. Trends in biomass of lake herring appear to be linked to recruitment of strong year classes and reproductive failures.
Rainbow smelt biomass in U.S. waters during 1978-2003 was ranked second behind lake herring and accounted for 20% of the total biomass. In 1978-1979 smelt was the dominant prey fish, representing 40-50 % of the total biomass. Prior to the monitoring period, smelt populations were at record levels in Lake Superior. In 1978-1979, the beginning of the monitoring period, smelt biomass in U.S. waters peaked but subsequently dropped by more than 85% by 1981.
Between 1986 - 1995, biomass fluctuated and then declined steadily after 1995, reaching record low levels in 2002 and 2003. Unlike lake herring, strong year classes of smelt did not fluctuate so widely. Estimates of total mortality show that loss of adult fish >3 years of age increased sharply after 1978 and mortality rates have remained high ever since, such that fish 4 years and older have represented less than 1.3% of the total population since 1981. Trends in smelt biomass were similar among jurisdictions in U.S. waters.
During the 1989-2003 monitoring period, trends in smelt biomass in Canadian waters shared features with those in U.S. waters, but biomass levels were consistently much higher in Canadian waters until 2001. In 2002, smelt biomass in Canadian waters plummeted similar to the low levels observed in U.S. waters.
Bloater mean biomass in U.S. waters during 1978-2003 ranked fourth behind lake herring, rainbow smelt, and lake whitefish, and accounted for 11.9% of the total community biomass. In U.S. waters, bloater biomass was low during 1978-1983, then more than doubled in 1984-1986 and remained relatively high through 1993. After the peak in 1992, biomass declined to low levels in 1994-1995, but recovered partially by 1998. Trends in biomass in U.S. and Canadian jurisdictions between 1989-2001 were very similar.
Whitefish biomass in U.S. waters during 1978-2003 was second only to lake herring and accounted for 19% of the total community biomass. During 1978-1983, biomass of whitefish was low in U.S. waters, then increased during 1984-1986 and then fluctuated to the present time. Year class strength in U.S. waters varied by a factor of 9 over the 25 year monitoring period, which was much less than that for other coregonids. As a result, there were numerous moderate to strong year classes, especially after 1987 when population levels and biomass had fully recovered. Trends in whitefish biomass in Canadian waters were similar during 1989-2003, but dropped to record lows in 1999-2003.
Ninespine stickleback was a relatively minor species in U.S. and Canadian waters during 1978-2003, and accounted for 2% of the total community biomass.
Trout-perch was another relatively minor species in U.S. and Canadian waters during 1978-2003; mean biomass accounted for 1.4% of the total community biomass.
Slimy sculpin, another minor species, was the most abundant sculpin species in U.S. waters during 1978-2003. In Canadian waters, slimy sculpin biomass has tended to be higher than in U.S. waters, but the trends for the 1989-2003 period were similar. Like that in U.S. waters, slimy sculpin biomass in Canadian waters declined to the lowest levels in the time series during the 2000-2002 interval.
Lakewide trawl assessments indicate that total community biomass, including lake trout, has been in decline since the mid-1990s, which has occurred despite what appears to be an ample food base. Further increases in lake trout biomass in Lake Superior depend heavily on increasing stocks of lake herring. The key, then to further restoration of the Lake Superior fish community is to fully recover lake herring, the principal prey species
Sea Lampreys in Lake Superior 2003
· Lake Superior has 1,566 (833 Canada, 733 U.S.) tributaries.
· 139 (47 Canada, 92 U.S.) tributaries have historical records of production of sea lamprey larvae.
· 68 (29 Canada, 39 U.S.) tributaries have been treated with lampricides at least once during 1993-2003.
· Of these, 51 (19 Canada, 32 U.S.) tributaries are treated on a regular cycle.
Lampricide treatments are system-atically scheduled for tributaries harboring larval sea lampreys to eliminate or reduce the populations of larvae before they recruit to the lake as parasitic adults. USFWS (Service) and Department of Fisheries and Oceans Canada (Department) treatment units apply formulations of the lampricides TFM and Bayluscide to scheduled tributaries and lentic areas. Specialized equipment and techniques are employed to provide concentrations of lampricides that eliminate about 95% of the lamprey larvae and minimize the risk to non-target species. Service and Department treatment units administer and monitor doses of the lampricide TFM, sometimes augmented with Bayluscide 70% Wettable Powder, to scheduled tributaries.
Treatments with TFM were completed in 12 tributaries (6 Canada, 6 U.S.).
· Treatments of all Canadian tributaries were considered successful with the exception of the Batchawana River. Low discharge conditions may have compromised treatment effectiveness in the lower 10% of the watershed.
· Bayluscide granules were applied to lentic areas of Lake Helen. One area, located off the mouth of the upper Nipigon River, was treated in conjunction with the TFM application of the upper Nipigon River to take advantage of the reduced flows required for the river treatment.
· The Dead River was eliminated from the lampricide treatment schedule when an extensive flood destroyed all infested habitat.
· The Marengo River (Bad River) was treated further upstream than ever previously treated to eliminate a source of residual larvae.
Male sea lampreys are captured during their spawning migrations in 20 tributaries to lakes Superior, Michigan, Huron, and Ontario, and the St. Marys River and transported to the sterilization facility at the Hammond Bay Biological Station. At the facility sea lampreys are sterilized with the chemosterilant bisazir. They are then delivered and released into the St. Marys River. Laboratory and field studies have shown that treated male sea lampreys are sterile, sexually competitive, and numbers of eggs that hatch in sterile male nests are reduced. A total of 666 spawning-phase male sea lampreys were transported to the facility from the Brule River.
· A new seasonal stop log barrier was constructed in Furnace Creek during 2003.
· New construction projects are in various stages of development on the Sucker and Bad Rivers and Harlow Creek.
· Assessments of populations of sea lamprey larvae were conducted in 81 tributaries (38 Canada, 43 U.S.) and offshore of 6 tributaries (1 Canada, 5 U.S.).
· 4,838 sea lampreys were trapped in 24 tributaries during 2003.
· The estimated population of spawning-phase sea lampreys for 2003 was 86,778 (western U.S. 30,107, eastern U.S. 56,671 and Canada). ²
Wisconsin Lake Superior Fishery
Mean catch-per-unit-effort (CPUE) of lake trout in WI-1 and WI-2 decreased in 2003. Although hatchery fish have been decreasing gradually, the decrease in native fish CPUE was inconsistent with recent trends. Lake trout stocking is no longer necessary in WI-2 and the 1994 year class was the last to be stocked. Lake trout will continue to be stocked in WI-1 until the stocking protocol established by the Lake Superior Technical indicates otherwise.
Spawning assessments were conducted on two reefs in October to monitor trends in abundance. The population at Gull Island Shoal declined in the 1950s and by 1961, no females were sampled during annual assessments. Spawning lake trout abundance has continually increased due to sea lamprey control, sport and commercial harvest restrictions and the creation of the Gull Island Refuge in 1976. The Gull Island Shoal stock-recruitment relationship is linear, indicating the population still has the capacity to increase. Spawning lake trout abundance has remained stable at Sand Cut Reef.
Lake Herring Assessment – Lake herring abundance increased dramatically during the late 1980s due to the exceptional year class in 1984 and several in the late 1980s. Those strong year classes are now declining in abundance and are being replaced with the 1998 year class, which accounted for 64% of the spawners in 2003. Spawner abundance declined in 2003 despite the strong 1998 year class.
An annual creel survey was conducted at all major ports along the Wisconsin shoreline. In 2003, an estimated 42,597 individual angler trips were made on Lake Superior, resulting in 201,132 angling hours. The harvest was estimated at 23,058 salmonids. 26 charter fishing operations were active in 2003, down from a peak of 50 licenses in 1990.
Wisconsin has 10 State licensed commercial fishers operating in Lake Superior. Whitefish and lake trout are primary targets. Other commercial species harvested include lake herring, siscowet lake trout, deep-water chubs (cisco) and smelt.
Wisconsin DNR operates three sea lamprey barriers on Lake Superior. The Middle River barrier has been in operation since 1984, the Iron River barrier since 2002 and the Brule River barrier/fishway since 1985. In 2003, 1,975 sea lamprey were captured at the Brule River barrier.
Lake Trout 45,154
Brown Trout 98,452
2004 Proposed Salmonid Stocking
Lake Trout 89,400
Brown Trout 80,000
Chinook 200,000 ²
Minnesota Lake Superior Fishery 2003
The Minnesota waters of Lake Superior encompass three statistical districts. In 2003 marking rates in MN-1 decreased, while in MN-2 and MN-3 they increased when compared to 2002. Total marks per 100 lake trout in 2003 were highest in MN-3. Compared to 2002, lamprey marks per 100 lake trout in 2003 increased for the two larger size groups and decreased slightly for the two smaller size groups. Total marking rate increased slightly from 6.2 to 6.6 marks per 100 lake trout.
Lake Trout – The catch per unit effort (CPUE) of stocked lake trout decreased from 2002 to 2003. The total CPUE of stocked lake trout in the May assessment generally increased from 1976-1982, then stabilized at about 50 lake trout/1,000 m of net through 1991, and has since generally declined to a low of 7.8 lake trout/1,000 m in 2003. The average total CPUE of stocked lake trout during the 1992-2003 period was well below the 1976-1991 average. There has also been a lakewide decline in survival of stocked lake trout.
Total CPUE of wild lake trout declined in 2003 to 21.1 lake trout/1,000 m, but is still about three times the catch rate for stocked lake trout. The rate of decline was not as large as that reported in 2002 when the CPUE decreased by about half. Unusually high numbers of wild fish were captured in 2000 and 2001.
Lake herring – Lake herring abundance has increased substantially in the commercial catch since 1985. In 2003, harvest of herring in the gill net fishery was 292,966 lbs., down from 375,946 lbs. in 2002. The adult lake herring stock vulnerable to the commercial fishery appears to be decreasing in Minnesota waters, as indicated by the commercial catch statistics from 1995-2003. However, a very strong 1998 year class which was well represented in the USGS 1999 spring forage survey has started recruiting to the fishery as indicated by the occurrence of many younger, smaller fish in the 2003 harvest. The 1998 year class of lake herring was the strongest recorded in Minnesota waters since 1990 and now accounts for much of the harvest.
Rainbow smelt – In 2003, the spring rainbow smelt spawning run along the Minnesota shore of Lake Superior remained at a very low level, and few fish were captured in the dip net fishery, compared to the pre-1980 period. From 1980-1990, commercial harvest had stabilized at approximately 15% of the average harvest during the 1970s. Commercial harvest in the 2002 pound net fishery was 18,180 lb. and decreased to 2,037 lb. in 2003. In 2003 there was only one smelt fisherman in the pound net fishery. No commercial trawling for smelt occurred in 2003.
In 2004, Minnesota plans to produce and stock three species of trout and salmon. Two strains of rainbow trout will be produced: steelhead and Kamloops. All steelhead will originate from Minnesota stocks. The Chinook salmon program was revised in 1998. Because of extremely low Chinook salmon returns to the French River Trap, not enough gametes could be collected to sustain a program. The decision was made to obtain gametes from the Swan River, Lake Huron. The new quota for Chinook salmon is 355,000 fingerlings. From 1998-2001 Minnesota secured eggs from Lake Huron. Starting in 2002, gametes were again collected at the French River Trap and used to produce Chinook salmon fingerlings for the stocking program. In 2004, Minnesota plans to stock approximately 270,000 lake trout. In 2003, lake trout stocking was discontinued in statistical district MN-3 because the criteria to discontinue stocking was met. ²