Danny K. Tanner

Habitat Fingerprints for Lake Superior Coastal Wetlands Derived from Elemental Analysis of Yellow Perch Otoliths

Abstract Assessing the ecological importance of coastal habitats to Great Lakes ecosystems requires an understanding of the ecological linkages between coastal and offshore waters. Elemental analysis of fish otoliths has emerged as a powerful technique that can provide a natural tag for determining nursery area affiliation, population structure, and movement of individual fish. Since the elemental composition of fish otoliths reflects some of the environmental conditions under which a fish was reared, otolith chemistry can record differences in ambient water conditions specific to habitats used during a fishs life history. Although few studies have been conducted in freshwaters, trace element analysis of marine fish otoliths has proven useful in identifying the chemical signatures unique to particular spawning and nursery habitats. To examine the utility of this method in freshwater, sagittae were removed from 275 young-of-the-year yellow perch Perca flavescens captured from eight wetlands in western Lak...

Toxicity of selected controlled release and corresponding unformulated technical grade pesticides to the fathead minnow Pimephales promelas

Fathead minnows were exposed to three encapsulated slow-release pesticide formulations and three corresponding technical grade products used in their manufacture. Static 4-day LC50 values derived from aged stock solutions indicate increased toxicity with time for encapsulated methyl parathion, diazinon and their technical grades. The technical grades, however, were more toxic than the encapsulated. Encapsulated Dursban was less toxic with time, whereas toxicity remained similar with time for the technical grade. Flow-through 4-day LC50 values for methyl parathion, Penncap-M, Dursban, Dursban 10 CR and diazinon are 5·36, 6·91, 0·14, 0·12 and 6·9 mb litre−1, respectively. In general, long-term toxicity was similar for both pesticide forms. Growth (weight) was the most sensitive parameter measured in the 32-day embryo-larval tests, except for the Dursban 10 CR study where it was equally as sensitive as survival. Growth effects occrred at >0·31– 0·38– 0·0016– 0·0022– 0·050–<0·090 and .0·040–<0·076 mg litre-1 for methyl parathion, Penncap-M, Dursban, Dursban 10 CR, diazinon and Knox Out 2 FM, respectively. Water solubilities were slightly lower for the encapsulated compounds. Estimated half-lives were 18 days for methyl parathion and 15 days for Penncap-M; 41 days for Dursban and > 200 days for Dursban 10 CR and approximately 30 days for diaznom and > 230 days for Knox Out 2 FM.

Toxicity of chlorpyrifos, endrin, or fenvalerate to fathead minnows following episodic or continuous exposure

Fathead minnow larvae (Pimephales promelas) were exposed to three individual pesticides during brief or continuous exposure in 96-hr and 28- to 30-day toxicity tests. Continuous exposure 96-hr LC50 values for chlorpyrifos, endrin, and fenvalerate were 122.2, 0.7, and 0.85 micrograms/liter, respectively. Continuous exposure chronic effect concentrations were chlorpyrifos, 2.1 micrograms/liter (increased deformities); endrin, 0.38 micrograms/liter (reduction in growth); and fenvalerate, 0.36 micrograms/liter (reduction in survival and growth). Brief exposure chronic test results indicated that fathead minnow exposure to chlorpyrifos for as few as 5 hr at a concentration similar to a continuous exposure 96-hr LC50 value resulted in increased deformities and a reduction in growth, whereas a 48-hr exposure at a concentration similar to a continuous exposure 96-hr LC50 value was required to cause a reduction in growth for endrin and a reduction in survival and growth for fenvalerate. It is suggested that although constant exposure laboratory tests are essential for hazard assessment, the relationships of exposure duration and toxicant intensity to ecotoxic effects are necessary for reliable risk assessments and implementation of water quality standards.

The acute toxicity of kelthane, dursban, disulfoton, pydrin, and permethrin to fathead minnows Pimephales promelas and rainbow trout Salmo gairdneri

Abstract Flow-through acute lethal toxicity tests were conducted with kelthane, dursban disulfoton, pydrin and permethrin using rainbow trout Salmo gairdneri and fathead minnows Pimephales promelas in Lake Superior water. Pydrin was the most toxic pesticide tested to both species of fish and was followed in order of decreasing toxicity by permethrin, dursban, kelthane and disulfoton. Rainbow trout were more sensitive than fathead minnows to all five pesticides. The 96-h LC 50 values (μg litre −1 ) for rainbow trout and fathead minnows, respectively, were: pydrin, 2·1 and 5·4; permethrin, 7·0 and 15·6; dursban, 8·0 and 203·0; kelthane, 210·0 and 510·0 and disulfoton, 3020·0 and 4000·0.

Toxicity of the synthetic pyrethroids, permethrin and AC 222, 705 and their accumulation in early life stages of fathead minnows and snails

Abstract Early life stages of fathead minnows ( Pimephales promelas ) were exposed to permethrin and AC 222, 705 and snails ( Helisoma trivolvis ) were exposed to permethrin in continuous flow-through exposures for approximately 30 days. Saturated solutions of each pesticide were used to avoid the use of solvents. Survival of newly hatched larvae and early juveniles was found to be the most sensitive measure of effect on fathead minnows of both pesticides. AC 222, 705 was approximately 20 times more toxic to fathead minnows than permethrin by the end of the test period. Based on the chronic limits, as defined in these tests, the predicted chronic no-effect concentrations for fathead minnows were between 0.66 and 1.4 μ/l for permethrin and 0.03 and 0.07 μ/l for AC 222, 705. The no-effect concentration for permethrin and snails was ≥ 0.33 μ g/l. The chronic values for these compounds were approximately one-sixteenth and one-fourth of the corresponding 96-h LC 50 values, respectively, for fathead minnows in Lake Superior water. The mean bioconcentration factors (BCFs) for permethrin were 2800 for fathead minnows and 800 for snails. The mean BCF for AC 222, 705 and fathead minnows was 4000. Residue concentrations for both pesticides increased with increased water concentrations.

Acute and chronic toxicity of triphenyltin hydroxide to fathead minnows (Pimephales promelas) following brief or continuous exposure.

Fathead minnow larvae (Pimephales promelas) were exposed to triphenyltin hydroxide (TPTH) during brief (single pulse) or continuous exposure in 96-h and 30-day toxicity tests. The continuous exposure 96-h LC(50) value was 7.1 microg litre(-1). Brief exposures for 12 to 72-h gave 96-h LC(50) values that ranged from 61.8 to 6.0 microg litre(-1), respectively. The continuous exposure 30-day chronic effect concentration, based upon reduced growth, was 0.23 microg litre. Survival was significantly reduced at 2.0 microg litre(-1). Brief exposures for 24, 48, and 72-h in 30-day tests significantly reduced survival and growth at 13.0, 13.0 and 60.0 microg litre(-1) respectively. It is suggested that both toxicant concentration and exposure duration are important factors to consider in the risk assessment of potential pesticide hazards in the environment.

Reconstructing Habitat Use and Wetland Nursery Origin of Yellow Perch from Lake Superior using Otolith Elemental Analysis

Abstract The use of otolith elemental composition as a natural tag has emerged as a powerful tool for managing and understanding the ecology of marine fish populations. The approach remains relatively untested in fresh waters, so we examined its utility for reconstructing habitat use and wetland nursery origin in Lake Superior. We analyzed the otolith margin of adult yellow perch, Perca flavescens , as an indicator of recently occupied habitat, and the juvenile region of the otolith core as an indicator of nursery area. To characterize elemental fingerprints, all otolith samples were analyzed for Ca and 13 minor and trace elements using mass spectrometry. We found differences in the otolith concentrations of several elements between yellow perch inhabiting coastal wetlands and those inhabiting the adjacent nearshore waters of Chequamegon Bay. The most striking difference was the high concentration of Sr in the sagittal margins of wetland-caught fish relative to those captured in the bay. Based on differences in otolith Sr concentrations alone, fish from bay and wetland habitats could be distinguished with 100% accuracy. We also found that elemental fingerprints derived from otolith cores of adult yellow perch were similar among fish captured from wetlands adjacent to Chequamegon Bay but quite distinct for one site outside of the bay, suggesting these fish came from a separate population from those in Chequamegon Bay. Overall, these results encourage us that elemental fingerprinting techniques will be useful for estimating the relative importance of different coastal wetland habitats to wetland-dependent species in the Great Lakes.

Effects of esfenvalerate on the reproductive success of the bluegill sunfish, Lepomis macrochirus in littoral enclosures

Adult bluegills were exposed to the synthetic pyrethroid esfenvalerate, during a reproduction study conducted in six littoral enclosures located in a 2-ha pond near Duluth, Minnesota. Bluegill reproductive success was determined after two applications of esfenvalerate at nominal concentrations of 0.0, 0.01, 0.08, 0.20, 1.0, and 5.0 μg/L. Responses measured were adult behavior and spawning, embryo hatchability, larval survival until swim-up, young-of-the-year (Y-O-Y) growth, and total biomass. All adult bluegills died within one day following the first application at 5.0 μg/L. Successful spawning and resulting hatching of offspring were observed at all esfenvalerate concentrations except 5.0 μg/L. Following exposure at 1.0 μg/L, spawning was delayed for 15 days and few or no larvae survived. Bluegill Y-O-Y growth was reduced by 62, 57, and 86% in the 0.08, 0.20, and 1.0 μg/L esfenvalerate treated enclosures. Delayed adult spawning and reduced Y-O-Y growth may result in poor Y-O-Y overwinter survival which would result in a diminished or extirpated year class.

Turbidity Tolerances of Great Lakes Coastal Wetland Fishes

Abstract Despite recent interest in assessing the condition of fish assemblages in Great Lakes coastal wetlands and a concern for increasing turbidity as a major stressor pathway influencing these ecosystems, there is little information on fish tolerance or intolerance to turbidity on which to base wetland assessment metrics. Existing studies have borrowed tolerance designations from the stream literature, but they have not confirmed that the designations apply to Great Lakes wetlands or that designations based on tolerance to degradation in general apply to turbidity in particular. We used a published graphical method to determine turbidity tolerances of Great Lakes fishes based on their pattern of occurrence and relative abundance across coastal wetlands spanning a turbidity gradient. Fish composition data were obtained from fyke-net and electrofishing surveys of 75 wetlands along the U.S. shoreline of the Laurentian Great Lakes, representing a turbidity range of approximately 0–110 nephelometric turbid...

Relative Abundance and Distribution of Ruffe (Gymnocephalus cernuus) in a Lake Superior Coastal Wetland Fish Assemblage

Fish assemblages from Allouez Bay Wetland in the St. Louis River estuary were sampled with fyke-nets from May to October, 1995, to characterize typical use patterns in different seasons and microhabitats. The relative abundance and distribution of ruffe (Gymnocephalus cernuus) in these habitats was of interest because their recent invasion into the Great Lakes has the potential to disrupt native fish assemblages. A total of 15,867 fish comprised of 34 species were captured in 2,300 h of netting. The majority offish over the whole study were caught in the outer marsh (63%, 9,957 individuals), and seasonally during late June (7,384 individuals/4 net-nights) and early May (2,281 individuals). Yellow perch (Perca flavescens), brown bullhead (Ameiurus nebulosus), emerald shiner (Notropis atherinoides), and silver redhorse (Moxostoma anisurum) were the most abundant species, comprising 85 percent of the total catch. Ruffe was the seventh most abundant species captured (294 individuals), comprising only two percent of the total catch. They were the fifth most abundant species in the outer marsh, but only thirteenth most abundant in the inner marsh. Ninety-one percent of all ruffe (268 individuals) were caught in the outer marsh. Of the 75 species by life-stage combinations derived by classifying all individuals captured into one of 3 life stage categories (YOY, yearling, and adult), yearling ruffe were the twelfth most abundant, adult ruffe were sixteenth, and YOY ruffe were twenty-seventh. While ruffe have been the most abundant fish captured in bottom trawls in St. Louis River estuary during the 1990s, our results indicate the invasion of ruffe in shallow, heavily vegetated areas like those in Allouez Bay has been much less successful. Our results also suggest further degradation of coastal wetlands and other vegetated habitats would eliminate significant refugia from ruffe competition and could lead to increased dominance of ruffe in shallow water habitats in the Great Lakes.