Comprehensive watershed planning in New York State: The Conesus Lake example

Conesus Lake and its agricultural watershed exemplify many of the challenges of effectively managing land and water resources for multiple uses. One of the smaller of New York's Finger Lakes, Conesus Lake is eutrophic with abundant growth of rooted aquatic plants and algae. The trophic condition of the lake has been relatively stable for decades as measured by phosphorus concentrations and hypolimnetic dissolved oxygen depletion rates. However, recent changes to the lake ecosystem have led to diminished water clarity, higher density of macrophytes in shallower water, and the proliferation of nearshore macroalgae. These water quality changes caused serious concern regarding the ultimate causes of the degradation; community conflict was evident between the upland agricultural producers and shoreline residents. With funding from the New York State Department of State, Livingston County Planning Department led a successful effort to engage the community in a science-based assessment of the interrelationship of land use and lake water quality. The planning process was designed to develop consensus that the lake is a shared resource and that effective solutions require changes by many stakeholders. The outcome of this effort was the Conesus Lake Watershed Management Plan. An intermunicipal Conesus Lake Watershed Council was formed to implement the plan's recommendations. The Council has been active for 5 years and has weathered two local elections with full community support. Although many factors contribute to the success of this watershed planning initiative, the importance of a science-based foundation and ongoing efforts to build political consensus cannot be overstated.     

Population Characteristics and Movements of Lake Sturgeon in the Sturgeon River and Lake Superior

A 2.6-km reach of the Sturgeon River, containing two sets of rapids, is an important spawning site to a native population of lake sturgeon, Acipenser fulvescens, which ranges widely into southern Lake Superior. Similar spawning areas in other Great Lake tributaries may also be important to the protection and rehabilitation of lake sturgeon throughout this region. Information on range and habitat needs of this species, which is considered “threatened” in the State of Michigan, was obtained from the Sturgeon River spawning population from 1987 to 1995. Radio-tracking was employed to determine movements and habitat use by post-spawning lake sturgeon. Telemetry data from 25 fish were supplemented with data obtained through identification tag returns. During the study 925 lake sturgeon were handled; 86 returned to spawn 1 time and 12 returned 2 times. Spawning intervals for male lake sturgeon were commonly 2, 3, or 4 years; yearly spawning by males was never observed. Females returned to spawn after 3 to 7 years. From 1991 to 1995 the male:female sex ratio at the spawning site was 1.25 to 2.7. In 1990 13 of 18 adults fitted with transmitters moved out of the river within 9 days. Upon reaching Portage Lake nine individuals spent time in shallow (maximum depth, 6 m) Pike Bay. After 3 to 53 days (mean, 22) tagged fish moved into the deeper water of Portage Lake (maximum depth, 17 m) and ranged more widely. Three fish were located in Keweenaw Bay, Lake Superior by late August. Identification tag returns reveal that lake sturgeon traveled 70 to 280 km from the spawning site throughout southern Lake Superior.     

Deepwater Spawning by Lake Trout (Salvelinus namaycush) in Keuka Lake,New York

Egg deposition in deep water by a self-sustaining lake trout population is reported for Keuka Lake, one of the Finger Lakes of New York. Deep water spawning may be a critically important component to the restoration of lake trout in the Great Lakes. In 2002, spawning occurred on or about December 6 at a water temperature of 6.7°C at depths ranging from 24.6 to 27.7 m, with an average egg abundance of 1,318 eggs·m⁻². The population, presumably the native strain, spawned on a steep slope (30–40°) on small shale substrate with little interstitial space. Abundance of egg predators was low and limited to slimy sculpins (6.9 sculpins·m⁻²). Early mortality syndrome (EMS), associated with an alewife diet-mediated thiamine deficiency in parents, was detected in larvae reared from the wild-caught eggs, but was of insufficient magnitude to eliminate natural reproduction in Keuka Lake.     

Lake Trout (Salvelinus Namaycush) Spawning Habitat in Seneca Lake,New York

Lake trout from Seneca Lake provide an important source of stock for Great Lakes rehabilitation but the lake trout in Seneca Lake have been hatchery supported, themselves, for many years. Hatchery catch data show a continued decline in lake trout population and this is assumed to reflect changes in hatchery stocking, fishing pressure, and lamprey predation. A commensurate increase in the smelt population, since 1973, may have also contributed to the decrease of natural recruitment by lake trout. No indication of reduced egg survival was found in the hatchery which might be related to lake contamination effects. Our survey observations (1980–81) indicate that the lower parts of deep water cobble gravels have become much degraded by fine particulates, making such sites unsuitable for spawning lake trout. It is thought that natural replacement in Seneca Lake is strongly dependent on successful hatch of eggs laid at depths of 25 to 35 m, but the observed relationship between egg deposition and optimal thermal conditions seems to be anomalous. Since no controlling relationship was found between long-term decline of the lake trout population and climatic variation, it is believed that degradation of lake spawning sites has strongly influenced natural recruitment.     

An Economic Analysis of Integrated Fisheries Management: The Case of the Lake Michigan Alewife and Salmonid Fisheries

Intense predator-prey relationships exist between stocks of alewives and salmonids in Lake Michigan. In this paper, the economic implications of these biological interactions are explored and suggestions regarding efficient fisheries management options are made. A theoretical optimal control model is developed which delineates conditions for optimizing alewife and salmonid harvest rates. Model results indicate that the indirect effects which harvesting in one fishery have on harvest costs and returns in the other must be considered if economic efficiency in alewife/salmonid management is to be achieved. Furthermore, marginal net social values associated with alewife and salmonid harvests must be equated. It is estimated that alewives currently have a marginal net social value close to zero compared to $4.10 per salmonid. These findings strongly suggest that utilization of alewife biomass as a forage base for predatory salmonids is more efficient than direct harvesting of alewives in a commercial fishery.     

Lake Sturgeon (Acipenser fulvescens) in Goulais Bay,Lake Superior: Cohort strength determinants and population viability

Lake Sturgeon (Acipenser fulvescens) is a species of conservation concern throughout North America, and healthy populations are rare. Earlier sampling efforts identified the Goulais Bay population in Lake Superior as a potentially healthy population after three years of sampling. With seven additional years of sampling, we updated the earlier analysis and developed a matrix population model to conduct a population viability analysis (PVA). We identified a non-linear relationship between cohort strength and May river discharge rate which was incorporated into the population model to evaluate the influence of future discharge scenarios on population persistence. Population size was estimated, with an open-population mark-recapture model, at approximately 5,200 juvenile Lake Sturgeon. This estimate equates to approximately 440 mature females and 625 mature males in the population. A population of this size has a probability of extinction of 4 % and 18 % over 250 and 1000 years under status quo conditions. If the May river discharge were to decrease in the future, which may represent the most likely scenario under future climate conditions, our model predicts an increased risk of population extirpation. This indicates that increased management actions may be required to ensure this population remains resilient.     

Seasonal Food of Juvenile Lake Trout in U.S. Waters of Lake Ontario

Stomach contents of 3,554 lake trout (Salvelinus namaycush), 100 to 449 mm in total length, captured with bottom trawls during April through October 1978–81 along the south shore of Lake Ontario were examined. Invertebrates appeared to be an important food of lake trout less than 200 mm long but were only occasionally eaten by larger fish. For all seasons and size groups of juvenile lake trout combined, the slimy sculpin (Cottus cognatus) was the principal forage fish, making up 42% (by weight) of identifiable fish remains. Young-of-the-year slimy sculpins were a major food of recently stocked yearling lake trout during July through October. Alewives (Alosa pseudoharengus) were the principal forage during April and May, and made up 28% (by weight) of the identifiable fish remains. They were rarely eaten during July and August, however, when lake trout remained in the hypolimnion and alewives were above it. Over 99% of the alewives eaten from April through August were yearlings and over 99% eaten during October were young-of-the-year. Rainbow smelt (Osmerus mordax) were the primary forage during July and August, but contributed only a small part of the diet during other seasons; overall, they made up 25% of identifiable fish remains. Johnny darters (Etheostoma nigrum) made up 4% of identifiable fish remains and were most common in stomachs of small lake trout during October.     

Characteristics of a Lake Sturgeon Spawning Population Sampled a Half Century Apart

A lake sturgeon spawning assessment study conducted in the late 1940s below a dam on the Ottawa River, Canada was repeated over a 3-year period in 2001–2004. The objectives of the survey were to determine whether lake sturgeon, a long-lived species, continue to congregate at this location during the spawning period and to assess changes in the characteristics of the spawning population since 1949. Eighty-three lake sturgeon were caught, including 10 recaptures, over the 3-year survey with the majority of sturgeon sampled in 2003. The Schnabel population estimate for the 2003 spawning stock was 202 (93–378; 95% C.I.). Mean size of lake sturgeon sampled in the current survey (118.0 ± 12.8 S.D.) was greater than in the historical survey (101.7 ± 11.5 S.D.). However, lake sturgeon < 110 cm TL comprised only 31.1% of the sturgeon sampled in this survey whereas they comprised the majority of the catch in 1949 (69.9%), suggesting the population is experiencing a recruitment problem. Weight-length relationships of lake sturgeon did not vary between studies. Growth differed between studies which may be a function of aging error.     

Nearshore Spatial Distribution of Fishes in Gill Net Samples,Cayuga Lake,New York

Cayuga Lake fishes were collected monthly with experimental gill nets at depths of 2 to 31.5 m. Horizontally-placed nets were arranged to allow determinations of vertical and inshore-offshore variation in fish distribution and occupied temperatures. Warmwater species concentrated in inshore and surface waters at 19-23° C during the summer. Coldwater species concentrated in hypolimnetic waters at 9-15° C during the summer. Seasonal inshore-offshore movements were evident with all species except those which were captured only close to shore (northern pike, carp, smallmouth bass, white sucker). Depth ranges in which greatest numbers of common species occurred in the summer (July-September) were: alewife, inshore and surface to 15.3 m; lake trout, 15.3 to 30.5 m or more; northern pike, inshore and surface to 15.3 m; rainbow smelt, 7.6 to 30.5 m or more; spottail shiner, inshore and 7.6 m; trout-perch, inshore and 7.6 to 15.3 m; yellow perch, inshore and 7.6 to 15.3 m. Mean occupied temperatures (° C) of common species during the summer were: alewife 18.4 to 20.9; lake trout, 12.5 to 13.6; northern pike, 19.4; rainbow smelt, 10.4-14.4; spottail shiner, 19.6 to 21.5; trout-perch, 18.7-21.3; yellow perch, 19.4 to 21.0. Depth distribution was obviously influenced by temperature preferences and also by availability of food in certain species. Catch size was directly related to water temperatures in several species.     

Distribution of Benthic Macroinvertebrates in Canadian Waters of Northern Lake Superior

Approximately 30 genera comprising 39 macroinvertebrate species have been identified in northern Lake Superior, including Nipigon Bay and Thunder Bay. The dominant taxa were the crustacean Pontoporeia affinis, the insect Chironomus spp., the oligochaete Aeolosoma beddardi and the pelecypod Pisidium spp.Intra-phyletic relationships were fairly common along molluscan taxa, probably resulting from their mutual affinity for warm shallow water conditions, but were negligible among the arthropods and annelids.     

Benthic Community Structure and Composition Among Rocky Habitats in the Great Lakes and Keuka Lake,New York

Benthic invertebrates were collected from 12 rocky sites in Lake Michigan, Lake Superior, and Keuka Lake, New York. Proportionate abundances of benthic components occurring in rock scrape (131 spp.) and pumped (167 spp.) samples (190 spp. total) were compared using coefficient of community (CC) and percent similarity of community (PSc). Pumped samples were judged better estimators of benthic community structure and composition than were rock scrape samples because they more thoroughly and instantaneously sampled the benthos. Rock scrape samples in particular were subject to loss of Amphipoda. Comparisons among sites using CC, PSc, and cluster analysis indicated two major clusters of sites, one dominated by Chironomidae and the other dominated for the most part by the amphipod Hyalella azteca. No water chemistry differences of biological importance were noted during the fall and no biological interactions, such as fish predation, could explain observed benthic community differences. The factor which best accounted for differences in the benthic community among sites was physical characteristics such as water temperature, shelter from excessive wave activity, and rock configuration. However, despite differences, the most remarkable feature among rock sites was their similarity since dominant taxa of Amphipoda, Chironomidae, Acarina, and to some extent Naididae, were quite predictable, although rank order of dominance changed from site to site. Similarity among sites was attributed to similar trophic conditions, while dissimilarity was attributed to physical characteristics acting within and upon each site.     

Potential for Fisheries Rehabilitation in the Hamilton Harbour-Cootes Paradise Ecosystem of Lake Ontario

Present and historical information on the status of the Hamilton Harbour-Cootes Paradise ecosystem is synthesized to evaluate the potential for fisheries rehabilitation. Although the Hamilton ecosystem is seriously degraded, it is the largest and most important warmwater fish habitat in western Lake Ontario. Habitat losses, hypolimnetic anoxia, contaminated sediments, nutrients, and sediment inputs are impediments to rehabilitation. Rehabilitation should focus on the warmwater fish assemblage as restoration of the historic coldwater fishery appears unlikely in the foreseeable future. Carroll's Point has the best potential for rehabilitation, the south shore does not have any potential, and the remaining areas fall in between these extremes. Cootes Paradise, which has moderate potential, is adversely affected by sediment inputs from Spencer Creek, nutrients from the Dundas sewage treatment plant, and a large carp population.     

Biogeochemical cycling of manganese in Oneida Lake, New York: whole lake studies of manganese

Oneida Lake, New York is a eutrophic freshwater lake known for its abundant manganese nodules and a dynamic manganese cycle. Temporal and spatial distribution of soluble and particulate manganese in the water column of the lake were analyzed over a 3-year period and correlated with other variables such as oxygen, pH, and temperature. Only data from 1988 are shown. Manganese is removed from the water column in the spring via conversion to particulate form and deposited in the bottom sediments. This removal is due to biological factors, as the lake Eh/pH conditions alone can not account for the oxidation of the soluble manganese Mn(II). During the summer months the manganese from microbial reduction moves from the sediments to the water column. In periods of stratification the soluble Mn(II) builds up to concentrations of 20 micromoles or more in the bottom waters. When mixing occurs, the soluble Mn(II) is rapidly removed via oxidation. This cycle occurs more than once during the summer, with each manganese atom probably being used several times for the oxidation of organic carbon. At the end of the fall, whole lake concentrations of manganese stabilize, and remain at about 1 micromole until the following summer, when the cycle begins again. Inputs and outflows from the lake indicate that the active Mn cycle is primarily internal, with a small accumulation each year into ferromanganese nodules located in the oxic zones of the lake.     

Nearshore Benthic Invertebrates of the Ontario Waters of Lake Ontario

Benthic invertebrates were collected by divers along 25 transects (depths of 2, 5, 10, and 20 m) between the Niagara River and Kingston during July 1981. Total standing stocks, which ranged from 1,600 m⁻² to 314,200 m⁻², were greatest on silt and clay, especially near the mouth of the Humber River, and smallest on rock. Of the 196 taxa which were recognized, Vejdovskyella intermedia, immature Tubificidae, Chaetogaster diaphanus, Potamothrix vejdovskyi, Tanytarsus, Pontoporeia hoyi, and Gammarus fasciatus were the most abundant and most frequently collected. Both inspection of the distributions of common taxa and ordination based on abundances of all taxa found at >5 stations indicated that organic enrichment, depth, and susceptibility to upwelling were the primary factors influencing the composition of invertebrate communities. Exposure to wave action was less important, and type of substratum had little effect. Overall, the nearshore fauna of Lake Ontario was less diverse, but more abundant than that of Lake Huron.     

Mercury and Zinc in the Sediments of Seneca Lake,Seneca River,and Keuka Outlet,New York

Levels of total mercury and total zinc in the sediments of Seneca Lake, New York, and of its principal tributary and outflow, show a pattern of industrial and municipal pollution in a predominantly rural environment. An interpolation technique based on the relationship of heavy metal concentration to overlying water depth is used to estimate the total mercury content of the upper 2 cm of Seneca Lake sediments, and the increment of mercury above an assumed unperturbed distribution. An approximate mass balance suggests that defunct industry and a 200 megawatt coal-burning power plant represent comparable pollution sources, and that most of the emitted mercury leaves the watershed in aqueous solution or as vapor. The distribution of zinc parallels that of mercury, with a relatively constant Zn/Hg ratio in the lake sediments.     

Distribution and Abundance of Larval Fish in the Nearshore Waters of Western Lake Huron

Ichthyoplankton was collected at 17 nearshore (bottom depth ≥5 m but ≤10 m) sites in western Lake Huron during 1973–75 with a 0.5-m net of 351-micron mesh towed at 99 m/min. Larvae of rainbow smelt (Osmerus mordax) dominated late spring and early summer catches and larvae of alewives (Alosa pseudoharengus) the midsummer catches. Larval yellow perch (Perca flavescens) were caught in early summer but were rarely the dominant species. The time of spawning and hatching, and thus occurrence of larvae, differed between areas but was less variable for alewives than for yellow perch. The appearance of larvae in Saginaw Bay was followed successively by their appearance in southern, central, and northern Lake Huron. Rainbow smelt were most abundant in northern Lake Huron and yellow perch and alewives in inner Saginaw Bay. Densities of either rainbow smelt or alewives occasionally exceeded 1/m³, whereas those of yellow perch never exceeded 0.1/m³. Abundance of alewives was usually highest 1 to 3 m beneath the surface and that of rainbow smelt 2 to at least 6 m beneath the surface. Important nursery areas of rainbow smelt were in bays and off irregular coastlines and those of yellow perch were in bays. All nearshore waters seemed equally important as nursery areas of alewives.     

Distribution of Mutagens and Toxicants in Lake Ontario Waters as Assessed by Microbiological Procedures

Water samples collected from inshore and offshore waters in Lake Ontario, Toronto waterfront and Hamilton Bay were tested for mutagenic activity (Ames’ Test) and presence of acute toxicants (Spirillum volutans test). Data indicate many inshore waters contain mutagenic compounds which cause reversion of Salmonella tester strain TA 1535. The majority of samples tested did not contain acute toxicants based on the Spirillum volutans test.