Thomas E. Lauer

Changes in Mottled Sculpin and Johnny Darter Trawl Catches after the Appearance of round Gobies in the Indiana Waters of Lake Michigan

Abstract We investigated the response of the mottled sculpin Cottus bairdi and the johnny darter Etheostoma nigrum to the invasion and proliferation of the round goby Neogobius melanostomus at three near-shore locations in southern Lake Michigan. Fish were collected by trawling from June through August, 1984–2002. Mean annual catches of mottled sculpin in trawl samples ranged from 0 to 4.4 fish/h from 1984 to 1998, whereas mean annual johnny darter catches ranged from 0 to 29 fish/h in the same period. Round gobies were first sampled in 1998, and the relative population abundance increased in the following years, ranging up to 371 fish/h at one site by 2001. From 1999 to 2002, only a single mottled sculpin and only 12 johnny darters were collected in 72 h of trawling. This study documents the rapid decline of the mottled sculpin and johnny darter following the round goby invasion to this portion of the lake.

Impacts of Channelization on Stream Habitats and Associated Fish Assemblages in East Central Indiana

Abstract The objective of this study was to determine the relationship between fish assemblage and habitat in streams dominated by an agricultural landscape. Fishes from 20 natural and 20 channelized streams were sampled using electrofishing gear in east central Indiana. Streams that had been channelized had a lower quality fish assemblage when compared to natural streams as measured by the Indiana V. Eastern Corn Belt Plain Index of Biotic Integrity (IBI). Stream habitat was evaluated using the Ohio EPA Qualitative Habitat Evaluation Index (QHEI), which indicated that channelized streams had lower quality primarily due to a loss of heterogeneous habitat. Pearson correlation analysis relating IBI and QHEI was positive and significant and demonstrated that a reduction in riffle and pool areas associated with channelization was the most significant factor influencing the fish assemblage. Furthermore, species lost when streams were channelized were predictable and often represented environmentally sensitive species. The results of this study suggested that stream channelization has a negative influence on the fish assemblage which should be recognized before any stream development.

Detection of pharmaceuticals and personal care products (PPCPs) in near-shore habitats of southern Lake Michigan

Pharmaceuticals and personal care products (PPCPs) have been documented throughout the United States freshwaters but research has focused largely on lotic systems. Because PPCPs are designed to have a physiological effect, it is likely that they may also influence aquatic organisms. Thus, PPCPs may negatively impact aquatic ecosystems. The objectives of this research were to quantify PPCP abundance in near-shore habitats of southern Lake Michigan and identify factors related to PPCP abundance. Stratified sampling was conducted seasonally at four southern Lake Michigan sites. All sites and depths had measurable PPCP concentrations, with mean individual compound concentrations of acetaminophen (5.36 ng/L), caffeine (31.0 ng/L), carbamazepine (2.23 ng/L), cotinine (4.03 ng/L), gemfibrozil (7.03 ng/L), ibuprofen (7.88 ng/L), lincomycin (4.28 ng/L), naproxen (6.32 ng/L), paraxanthine (1,7-dimethylxanthine; 46.2 ng/L), sulfadimethoxine (0.94 ng/L), sulfamerazine (0.92 ng/L), sulfamethazine (0.92 ng/L), sulfamethoxazole (26.0 ng/L), sulfathiazole (0.92 ng/L), triclocarban (5.72 ng/L), trimethoprim (5.15 ng/L), and tylosin (3.75 ng/L). Concentrations of PPCPs varied significantly among sampling times and locations (river mouth vs offshore), with statistical interactions between the main effects of site and time as well as time and location. Concentrations of PPCPs did not differ with site or depth. Temperature, total carbon, total dissolved solids, dissolved oxygen, and ammonium concentrations were related to total pharmaceutical concentrations. These data indicate that PPCPs are ubiquitous and persistent in southern Lake Michigan, potentially posing harmful effects to aquatic organisms.

Hydrological variation and fish assemblage structure in the middle Wabash River

Two years of fish assemblage data from 28 sites in the Wabash River Indiana, were examined for relationships with environmental variables using a multivariate approach, correspondence analysis. Upstream sites had lower mean daily discharge and lower coefficient of variation of daily discharge when compared to downstream sites. Although the fish assemblage changed along this 230-km river distance gradient, patterns were in contrast to the patterns in streams with unaltered flow regimes. We compared functional variables of fish species (species traits that describe habitat, trophic, morphological, and tolerance characteristics) by examining the proportion of their occurrences along the hydrological variability gradient (upstream–downstream). The general pattern showed assemblages from hydrologically stable (upstream) sites had higher proportions of generalist species that tend to occur in small to medium streams, prefer fast current velocities, generally occur over rocky, gravel, and sand substrates, and have low silt tolerance. In addition, there was a pattern relating the hydrological/longitudinal regime and the overall morphology of species: species with higher caudal peduncle/caudal fin ratios and more fusiform body shapes occurred in higher proportion in upstream sites.

Density-Dependent Growth of Yellow Perch in Southern Lake Michigan, 1984–2004

Abstract The relationship between the growth rates and abundance of yellow perch Perca flavescens was evaluated in the Indiana waters of Lake Michigan from 1984 to 2004. Relative abundance values were taken from trawl catch per unit effort, while growth rates were determined by back-calculation. Abundance was approximately one order of magnitude higher during the mid-1980s than in 1990–2004. Growth rates were negatively related to relative abundance and were sexually dimorphic (females grew faster than males). Regression analysis indicated that approximately one-half of the observed variation in growth was related to abundance; this was most apparent with smaller and younger fish. Lees phenomenon was shown to be present during periods of high exploitation and not present during periods of low exploitation. Both intraspecific competition and physiological changes associated with age at maturity are plausible explanations for these relationships.

Response of Yellow Perch Diet to a Changing Forage Base in Southern Lake Michigan, 1984–2002

ABSTRACT This study evaluated yellow perch (Perca flavescens) diet in southern Lake Michigan to determine whether prey consumed fluctuated with abundance of zooplankton, benthic invertebrates, and fish species during the period 1984 to 2002. Some change in benthic community abundance was evident from samples collected in the region during the period, including the naturalization of the round goby and the zebra mussel between 1993 and 2002. In addition, changes in fish abundance were evident from 1984 to 2002, when spottail shiner (Notropis hudsonius) and alewife (Alosa pseudoharengus) increased, while yellow perch, and rainbow smelt (Osmerus mordax) declined. Non-indigenous species eaten by yellow perch in 2002 included spiny water fleas (Bythotrephes longimanus), round gobies, and alewives with the latter two species dominating the diet by volume. Yellow perch did exhibit prey preferences, although they consumed a variety of different organisms over the period of study. This euryphagous characteristic of yellow perch is expected to promote its persistence in southern Lake Michigan, despite a changing prey base.

Yellow Perch Length–Fecundity and Length–Egg Size Relationships in Indiana Waters of Lake Michigan

Abstract This study was undertaken to quantify the length–fecundity and length–egg size relationships for yellow perch Perca flavescens in the Indiana waters of Lake Michigan. Data were pooled from gill-net collections made in 1985, 1986, and 1999, resulting in a wide length range of mature female yellow perch (172–332 mm total length (TL)). The length–fecundity relationship was log10 F = −3.220 + 3.223·log10TL (r 2 = 0.89), where F is fecundity. The mean preserved egg volume (V; mL) increased with yellow perch TL and was represented by the following equation: log10 V = −2.06 + 1.10·log10TL (r 2 = 0.48). These results reveal that larger females produced both more and larger eggs than did smaller females. Therefore, the intense harvest targeting large yellow perch (primarily females) in the 1980s and 1990s may have had an effect on the quantity and quality of eggs spawned by the population, possibly resulting in reduced recruitment.

Impact of Zebra Mussels (Dreissena polymorpha) on Fingernail Clams (Sphaeriidae) in Extreme Southern Lake Michigan

The demography of the zebra mussel (Dreissena polymorpha) and its impacts on native fingernail clams (Sphaeriidae) in Lake Michigan near Michigan City, Indiana were studied from 1992 to 1997 at 5, 10, and 15 m depths. Zebra mussel densities ranged from 0 to 6,209/m2, and were greatest at deeper stations. Size-frequency distributions suggest that initial colonization of the Michigan City area occurred in 1991, with adults typically living for 2 to 3 years. Abundance of adult populations may be limited by the sandy habitat typical of the areas studied and the occasional high-energy wave action in the shallow (5 m) near-shore zone of this area. Densities of fingernail clam ranged from 0 to 1,312/m2 and were also greatest at deeper stations. Approximately half of the fingernail clams shells between 1 and 2 mm in size were used as substrate for attachment by juvenile and adult zebra mussels, while over 90% of the clams > 2 mm showed attachment by zebra mussels. Overall median densities of Sphaeriidae decreased from 832/m2 to 13/m2 at the 15 m depth and from 234/m2 to 0/m2 at the 10 m depth during the study. It appears that zebra mussel colonization caused a dramatic reduction of Sphaeriidae density by 1997 that may eventually result in their loss from the area.

Habitat Influence on Fish Community Assemblage in an Agricultural Landscape in Four East Central Indiana Streams

ABSTRACT The objective of this study was to relate the quality of the fish community with habitat using the Index of Biotic Integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) in four agriculturally influenced streams in east central, Indiana. A total of 48 species was collected from 42 sites. IBI scores ranged from 14 to 48, and QHEI scores ranged from 29 to 83. There was a significant positive correlation between IBI and QHEI scores. Furthermore, we found significant positive correlations between IBI scores and four individual QHEI metrics (channel morphology, substrate, poollglide and riffletrun quality, and in-stream cover). Habitat influenced the fish assemblages with channelization and substrate being the primary structuring factors. The land use in this area is 70% agriculture, which has heavily influenced lotic character through anthropogenic practices.

Space as a limiting resource in freshwater systems: competition between zebra mussels (Dreissena polymorpha) and freshwater sponges (Porifera)

Species interactions between two types of sessile benthic invertebrates, the zebra mussel (Dreissena polymorpha) and freshwater sponges (Porifera), were evaluated in Michigan City IN Harbor in southern Lake Michigan during 1996. The study objective was to define whether competition plays a role in structuring benthic communities using experimental techniques commonly employed in marine systems. Sponges were uninhibited by zebra mussel presence and overgrew zebra mussel shells on hard vertical substrata. In contrast, zebra mussels did not overgrow sponge colonies, but did show an ability to re-capture hard substrata if relinquished by the sponge. The negative affect of sponges on zebra mussels through overgrowth and recruitment suggests interactions that could eventually displace zebra mussels from these benthic communities. However, seasonal reduction of sponge biomass from autumn through winter appears to allow the zebra mussel a periodic respite from overgrowth, preventing exclusion of zebra mussels from the community and allowing these two taxa to co-exist.