S.Lochmann Research

CHANGES IN LIPID AND FATTY ACID COMPOSITION OF WILD FRESHWATER ZOOPLANKTON DURING ENRICHMENT AND SUBSEQUENT STARVATION Steve E. Lochmann, Kelly J. Goodwin, and Christopher L. Racey
ABSTRACT: Concentrated wild zooplankton, harvested from freshwater ponds, has been used to feed hybrid striped bass larvae in tanks. However, growth and survival were superior when cultured rotifers and brine shrimp nauplii were offered as first feeds. We hypothesized that wild freshwater zooplankton could be enriched with HUFA in a manner similar to cultured zooplankton, which would enhance the nutritional value of the wild zooplankton. Wild zooplankton was enriched with Super Selco for 24 h. The lipid and fatty acid composition of wild zooplankton were monitored during the enrichment period and during the subsequent 72 h. Wild zooplankton had an initial total lipid level of 38 mg/g dry weight (DW), but lipid level rose to 72 mg/g DW after enrichment. Wild zooplankton was initially deficient in highly unsaturated fatty acids (HUFA), but after enrichment, wild zooplankton had a HUFA level of 10.41 mg/g DW. This was above a level recommended for good growth and survival of hybrid striped bass larvae. Nutritional state of wild zooplankton had returned to a pre-enrichment level 24 h after termination of enrichment. Therefore, harvesting and concentrating wild zooplankton from culture ponds, followed by 24 h of enrichment, offers producers another option for providing nutrition to early life history stages of hybrid striped bass larvae.
GOLDEN SHINER EGG SIZE, LIPID, FATTY ACID, AND AMINO ACID COMPOSITION DURING A SPAWNING SEASON Steve E. Lochmann, Kelly J. Goodwin, Rebecca T. Lochmann, Nathan M. Stone, and Troy Clemment
ABSTRACT: The Arkansas baitfish industry leads the nation in production of golden shiner Notemigonus crysoleucas. We examined egg volume and the lipid, fatty acid, and amino acid composition of golden shiner eggs, produced by a group of captive brood stock, over a season, as a means of suggesting nutritional requirements for brood stock diets. Average egg volume was 0.67 (+ 0.117) mm3 and egg volume declined during the spawning season. Golden shiner egg total lipid averaged 15.67 (+2.99) g per egg, and triacylglyceride (TAG) concentration was 6.82 (+1.81) g per egg. Based on the stability of egg total lipid, the percent neutral lipid, the consistent contribution of TAG to neutral lipid, the consistent TAG concentration, and the stable fatty acid and amino acid profiles, we conclude that lipid and amino acids in eggs from the experimental group were stable. The eggs should be equally sufficient for embryological development throughout the spawning season, but specific indices of egg and fry quality must be measured to confirm the links among egg size, biochemical composition, and egg and fry quality.
MORTALITY OF FISH LARVAE EXPOSED TO VARYING CONCENTRATIONS OF CYCLOPOID COPEPODS Emmanuel A. Frimpong and Steve E. Lochmann
ABSTRACT: Cyclopoid copepods can prey on freshwater fish larvae. The magnitude of predation is related to cyclopoid copepod size, cyclopoid copepod concentration, and larval size, and is also likely to be specific to certain species. We studied 5-d-old larvae of sunshine bass Morone chrysops x M. saxatilis (female white bass x male striped bass), golden shiner Notemigonous crysoleucas, fathead minnow Pimephales promelas, and goldfish Carassius auratus in four separate experiments. Larvae were stocked at 20/L into 2 L of water containing varying concentrations of the cyclopoid copepods Cyclops vernalis and Mesocyclops vericans to ascertain the effect of predation on mortality. We also compared predation rates observed in this study to rates predicted by an empirical model of crustacean predation on fish larvae from the literature. Sunshine bass alone were susceptible to predation mortality at the cyclopoid copepod concentrations used in this study. Mortality at 400 cyclopoids/L was significantly higher than mortality at 0-100 cyclopoids/L. Mortality at 500 cyclopoids/L was significantly higher than mortality at any other treatment concentration. Observed predation rates were much lower than predation rates predicted by the model. Stocking 4.11 mm TL or larger sunshine bass larvae into ponds with fewer than 300 cyclopoids/L probably represents a low risk of predation. Golden shiner, fathead minnow, and goldfish larger than 5 mm TL, stocked in ponds with less than 500 cyclopoids/L would likely experience little cyclopoid copepod predation.
RESPONSES OF BROOK AND BROWN TROUT TO STREAM REHABILIATION IN A MICHIGAN FOREST STREAM Veronica Bullock, A.J. Cline, and Steve E. Lochmann
ABSTRACT: The White River is located in west central Michigan, partially within the Huron-Manistee National Forests. The White River is one of the “Blue Ribbon” trout streams in the Lake Michigan drainage. It is wadeable, and the bottom consists of a combination of cobble, gravel, and sand. Developments, road construction, and crossings generally increase the amount of sand in the river and can negatively effect trout reproduction. Fisheries biologists with the Huron-Manistee National Forest undertook a stream rehabilitation project to minimize sand accumulation. Instream features were added to provide habitat, capture sand, increase pool depth and frequency, and minimize sand accumulation in the stream channel. Chapman’s mark/recapture estimates of population abundance were calculated in 2001 for brown Salmo trutta and brook Salvalenis fontinalis trout, prior to construction of instream structures, in two reaches of the river. Trout were collected with a barge electroshocker, identified, measured for total length, fin-clipped to mark the fish, and released downstream of the area being sampled. Subsequently, instream features (lunkers, deflectors, brush bundles, and platform structures) were put in place in the White River. In 2005, the two reaches were again sampled with the barge electro-fisher. Species were identified, measured, and fin-clipped as before. Chapman’s mark/recapture estimates of abundance were calculated for both trout species. We compared the size distributions prior to, and following the instream work using chi-square tests (=0.05). We also compared the abundance of both trout species prior to and following the rehabilitation work. Abundance of brown trout increased 1.5 to 2.5 times following instream work. Abundance of brook trout remained the same in one reach and increase 1.4 times in the second reach. Brown trout size distributions significantly increased in both stream reaches. Brook trout size distribution increased in the reach that did not exhibit a significant increase in abundance, but did not change in the reach that exhibited a significant increase in abundance. Trout populations exhibited improvements in either abundance or size structure, or both, following the instream work. This stream habitat management strategy may be a model for improvement of habitat in other Michigan trout streams.
THE FISH COMMUNITY OF MADDOX BAY RUNOUT Steven Mondragon, Richard Hines, and SteveE. Lochmann
ABSTRACT: Maddox Bay Runout connects Maddox Bay and Indian Bayou to the main channel of the White River. Concerns about stream crossings of Maddox Bay Runout for logging activities led to a survey of ichthyofauna. We sampled five randomly selected 0.1-mile segments of the 1.5-mile long stream. Ichthyofauna was sampled with one 10-minute backpack electrofishing sample per stream segment. We conducted two seine hauls per segment with a 30 x 6-ft knotless nylon seine with 3/16-inch mesh. We also set one minifyke net overnight in each of the stream segments. We collected 1763 specimens representing 48 species and 13 families. The two most prominent families were cyprinids and percids. Cypress minnow, blacktail shiner, weed shiner and ribbon shiner made up 80% of the individual fish collected during the study. The darter community in Maddox Bay Runout appears intermediate between Indian Bayou and the main channel of the White River.
EVALUATION OF SHORELINE SEINING AND MINI-FYKE NETS IN FLOODPLAIN LAKES S.J. Clark, John R. Jackson, and Steve E. Lochmann
ABSTRACT: Mini-fyke nets (MFN) were compared with shoreline seining (SS) to assess their relative abilities to describe littoral fish assemblages in 14 White River, AR floodplain lakes. Lakes ranged in size from 1 ha to 48 ha. Lakes greater than 2.4 ha were sampled using three MFN, while those smaller than 2.4 ha were sampled using two MFN. MFN were set for a 24-hour period. SS effort depended on the amount of open shoreline with a minimum of one seine haul and a maximum of 30 seine hauls conducted per lake. MFN were deployable in all of the 14 sample lakes; whereas SS could only be used in10 lakes due to woody vegetation. MFN collected more fish (3148) than SS (777). Overall, MFN species richness was 42 with 18 unique species. SS species richness was 25 with one unique species. In lakes sampled using both gears, Cyprinidae (42%), Centrarchidae (31%), and Clupeidae (9%) were most commonly caught in MFN whereas Poeciliidae (43%), Centrarchidae (30%), Cyprinidae (12%) were most commonly caught in SS. MFN were more efficient at sampling littoral fish assemblages than SS, required less manpower, and were fishable in all lakes.
INFLUENTIAL ENVIRONMENTAL/HYDROLOGICAL GRADIENTS AND SPATIOTEMPORAL PATTERNS IN FISH ASSEMBLAGES IN THE LOWER WHITE RIVER, ARKANSAS S.J. Clark, John R. Jackson, and Steve E. Lochmann
ABSTRACT: Five floodplain lakes within the White River National Wildlife Refuge were sampled in 2002, 2004, and 2005 to assess temporal variation of fish assemblages and lake environmental/hydrological variables. Lakes were sampled using boat electrofishing, experimental gill nets, and mini-fyke nets. Hydrologic variables were calculated by obtaining river stage that each lake connected to the river. Lakes sampled were highly diverse and provided a gradient of habitats allowing for shifts in fish assemblages but not drastic changes. A shift from cyprinid dominated lakes to cyprinid/centrarchid-dominated lake occurred. Relative abundance of cyprinids was highest during 2002. In 2004, a decrease in cyprinids abundance and increase in centrarchids abundance was observed and by 2005 relative abundance of cyprinids and centrarchids were nearly equal. Over the 3-year period, the decrease in the mean days lakes were connected to the river decreased. Catches in 2002 were dominated by emerald shiners, which are documented as preferring water with current. As the number of days connected decreased, the abundance of emerald shiners decreased while the relative abundance of more lentic species such as bluegill increased. Even though shifts in fish assemblages occurred within lakes, overall changes in the system were not evident.
EFFECTS OF DOUBLE-CRESTED CORMORANTS ON LARGEMOUTH BASS AND CRAPPIE IN LAKE CHICOT, ARKANSAS Christopher L. Racey, Amy Fenech, and Steve Lochmann

ABSTRACT: The mortality of crappie Pomoxis spp. and largemouth bass Micropterus salmoides populations due to depredation by double-crested cormorants (DCCOs) was quantified and the diet overlap of DCCOs and largemouth bass was evaluated for fall, winter, spring, and all seasons combined in Lake Chicot. The DCCOs consumed between 85 and 863 crappie and between 91 and

1032 largemouth bass per year. The DCCOs consumed an estimate of between 0.002% and 0.02% of the crappie population per year when using rotenone data to estimate population abundance or between 0.01% and 0.32% of the population when using creel survey data to estimate population abundance. The DCCOs consumed between 0.26% and 3.00% of the largemouth bass population using rotenone data to estimate population

abundance and between 0.03% and 1.53% using creel survey data to estimate population abundance. Diet overlap was biologically significant (greater than or equal to 60%) in the fall using percentage of total number and weight of prey, and relative importance index values for prey items. However, diet overlap was insignificant for diet measures used in all other seasons and for all seasons combined. Over-wintering DCCOs had little or no negative effects on largemouth bass and crappie populations in Lake Chicot.

TOXICITY OF ISOPROPYL METHYLPHOSPHONIC ACID TO EGGS OF
GOLDEN SHINER AND CHANNEL CATFISH

Chris Green and Steve Lochmann

Abstract: The Pine Bluff Arsenal has been ordered to incinerate a number of the chemical weapons currently stored at the facility in accordance with the Chemical Weapons Convention Treaty of 1997. Sarin is a nerve agent that acts as an acetylcholinesterase inhibitor. In the event of an accident during incineration, Sarin has the potential to be expelled into the environment. Isopropyl methylphosphonic acid (IMPA) is the main hydrolysis product of Sarin. Golden shiner Notemigonus crysoleucas and channel catfish Ictalurus punctatus eggs were exposed to IMPA. Fifteen fertilized eggs were placed in 250-mL test tubes containing 200 mL of water with five different concentrations of IMPA ranging from 35 to 75 mg/L for golden shiner and 115 to 175 mg/L for channel catfish. There were four replicates per treatment and a

control. Each test tube was aerated with air stones and maintained at a temperature of 25 ºC. The LC50 for eggs was determined by estimating the concentration of IMPA in which half of the individualsfailed to hatch. The LC50 for golden shiner egg hatchability was 60 mg/L (upper 95% C.I. 68 mg/L, lower 95% C.I. 53 mg/L). The LC50 for channel catfish was 157 mg/L (upper 95% C.I. 179 mg/L, lower 95% C.I. 144 mg/L). These results are critical in understanding the toxicological properties of this potential environmental contaminant. They are also important in conducting risk assessments relative to activities at the PBA.

Fluctuating Asymmetry and Relative Condition in Golden Shiner (Notemigonus crysoleucas) and Channel Catfish (Ictalurus punctatus) Reared in Sublethal Concentrations of Isopropyl Methylphosphonic Acid

C. C. Green and S. E. Lochmann

ABSTRACT: Stress during embryological development can result in small random differences between left and right sides of a bilateral trait. This fluctuating asymmetry (FA) has been proposed as a measure of the level of stress a group of organisms experienced during embryological development. Toxicants have been shown to increase FA among groups with increasing exposure during development. Studies have shown a relationship between asymmetry and indices of condition. The Pine Bluff Arsenal (PBA) has been ordered to incinerate a number of the chemical weapons currently stored at the facility in accordance

with the Chemical Weapons Convention Treaty of 1997. In the event of an accident during incineration, sarin or its decomposition products have the potential to be expelled into the environment. Isopropyl methylphosphonic acid (IMPA) is the main hydrolysis product of Sarin. This study examines the use of FA as an indicator of developmental stress due to sublethal exposures to a toxicant. We compared FA in fourteen morphological characters among groups of golden shiner (Notemigonus crysoleucas) and channel catfish (Ictalurus punctatus) exposed to sublethal concentrations of IMPA during embryological development. The relationship between relative condition and asymmetry are also examined.

Evaluation of Population Dynamics and Stocking Contribution of Largemouth Bass in Two Pools of the Arkansas River

Elizabeth Heitman, Chris Racey, and Steve Lochmann

Abstract: Largemouth bass stock characteristics and population dynamics in two pools of the McClellan-Kerr Arkansas River Navigation System were assessed. We evaluated the initial results of a fingerling stocking effort initiated by the Arkansas

Game and Fish Commission. Approximately 500,000 fingerling largemouth bass (app. 50 mm) were stocked into 10 pools of the Arkansas River. Largemouth bass were collected with a SmithRoot 7.5 GPP electrofisher, set at 60 cycles per second and voltage was adjusted between 4 and 5 amps of electricity. For pool 5, proportional stock density (PSD) was 47% and relative stock density preferred (RSD-P) was 16%.

For pool 9, PSD was 31% and RSD-P was 11%. Total annual mortality was 57% and 81 % for pools 5 and 9, respectively. Contribution of stocked largemouth bass fingerlings was evaluated by examining oxytetracycline marks.

POSSIBLE EFFECTS OF DOUBLE-CRESTED CORMORANTS AND LARGEMOUTH BASS PREDATION ON CRAPPIE IN AN ARKANSAS OXBOW LAKE.

Amy S. Fenech (G)*, Steve Lochmann, Andrew Radomski, David Wooten, and Mike Hoy

ABSTRACT: Mortality rates of age-0 to age-1 crappie (Pomoxis sp.) in Lake Chicot, an oxbow lake of the Mississippi River have been estimated to be approximately 90% in recent years. Increasing numbers of Double-crested cormorants (Phalacrocorax auritus) feeding on Lake Chicot are suspected by many anglers to be the cause of high mortality rates in sportfish populations.

However, Arkansas Game and Fish Commission report an increase in the density of largemouth bass (Micropterus salmoides) which may be having an affect on crappie survival. Collections of largemouth bass and cormorants will be taken seasonally with an additional collection of largemouth bass taken in the summer months. The diet and potential impact of largemouth bass and wintering cormorants will be investigated over a one-year period. We will attempt to use bioenergetic models to determine which of these factors is having a greater impact on the mortality of young sportfish in Lake Chicot.

An Evaluation of Stocking Crappie in Lake Chicot Arkansas

Christopher L. Racey and Steve E. Lochmann

ABSTRACT: Crappies (Pomoxis spp.) are the most sought after game fishes in Arkansas and their management is becoming more important. The Arkansas Game and Fish Commission (AGFC) received reports from local anglers in the early 1990s that crappie densities were declining in Lake Chicot, a 2024-ha natural

oxbow lake of the Mississippi River. In response, the AGFC initiated a stocking effort beginning in 1998. White crappie (P. annularis) fingerlings were marked by immersion in a 6-h bath of 500 mg/L of oxytetracycline-hydrochloride buffered with 2000 mg/L of dibasic sodium phosphate. Marking efficacy was 97%. Handling mortalities ranged from 20 to 72%. Initial contribution of stocked fish to the year classes was 9 and 15% for the 1998 and 1999 year classes, respectively. Trap nets were used subsequently to sample wild and stocked crappie. Stocked crappie contributed 0.8% to the 1998 year class at the time the fish entered the fishery. Stocked crappie did not contribute to the 1999 year class. Differential survival rates between wild and stocked fish may have accounted for the difference between initial and final contributions. We recommend that crappie be stocked only when the following conditions are met: 1) all fish should be marked prior to stocking; 2) 72-h handling mortality should be 20% or less; 3) stocked fish should make up at least 10% of the year class at recruitment; and 4) the cost-benefit ratio associated with stocking should be acceptable to the natural resource agency and the public.

USE OF RELATIVE ABUNDANCE AND CONDITION TO PREDICT SURVIVAL OF HYBRID STRIPED BASS (Morone chrysops x M. saxatilis) FINGERLINGS.

Chao Mwatela, Steve Lochmann* and Jerry Ludwig

ABSTRACT: Survival of palmetto bass during fingerling production averages about 35%, but survival of sunshine bass is usually lower and more variable. Reasons for variability include poor zooplankton management, handling mortality associated with stocking, or water quality problems. We hypothesized that survival could be predicted early in a fingerling production run by combining estimates of relative abundance with measures of nutritional condition.

Twelve 0.1-acre ponds were filled with well water and fertilized five days before being stocked with five-day-old sunshine bass fry. To induce variability in condition and survival, the twelve ponds were divided into a control and three treatment levels according to fertilization rate. The three treatments were twice, three times, and four times the control fertilization rate.
Fry were sampled from each pond once/week for three weeks. Fry that were concentrated in an area illuminated by a propane lantern were collected using a small plankton net (30 cm diameter mouth, 150 micron mesh). Fry were videotaped for morphometric analysis and preserved. After five weeks, ponds were seined twice and survival was determined. Morphometric measures, including body depth at the pectoral fin insertion (BDP) and body depth at the anus (BDA), were collected from the images.
Preliminary results suggest that abundance during the first week explained 60% of the variability in survival at five weeks. Abundance and a morphometric measure of condition (BDP/BDA) explained about 70% of the variability in survival. We concluded that relative abundance and condition may be useful together as a management tools during production of sunshine bass.

AN EVALUATION OF TREATMENTS AFFECTING ZOOPLANKTON POPULATIONS FOR WATER RE-USE AND EFFLUENT REDUCTION

Emmanuel Frimpong (G), and Steve Lochmann*

ABSTRACT: Regulation of aquaculture effluents in the United States is imminent. High potential costs are associated with effluent treatment, monitoring, and reporting. To circumvent strict compliance monitoring, and as a water conservation technique in response to declining aquifer levels, re-use of pond water is becoming a trend in the Arkansas baitfish industry. The biggest challenge to this practice is predation on fry by cyclopoid copepods present in this old water. The aim of this study was to evaluate methods of restarting the zooplankton bloom in pond water held from previous production operations.

The succession and abundance of zooplankton namely, rotifers, copepod nauplii, adult copepods and cladocerans in ponds containing old water, old water treated with 0.25 mg/L dimethyl(2,2,2-trichloro-1-hydroxyethyl)phosphate (Dylox), and mechanically filtered old water were compared to ponds filled with new well water. All ponds were fertilized twice a week with cottonseed meal and inorganic liquid fertilizer (N: P = 10:30) at the commercial rate. Zooplankton were sampled and water quality was monitored daily for 6 weeks.

It took 8 days to reach the peak (~1000/liter) of the rotifer bloom in new water. Compared with new water, mechanically filtered and chemically treated water had comparable numbers of rotifers by day 8 (see figure). Chemical treatment had the highest rotifer and copepod blooms (P<0.05). Filtration removed copepods and cladocerans, followed immediately by increased nauplii. Chemical treatment removed only cladocerans, resulting in rising and stabilizing copepod numbers. Mechanical filtration improved rotifer and nauplii abundance in early days, and greatly reduced and delayed copepod abundance. Mechanical filtration improved old water quality more than chemical treatment.