Steve Lochmann | University of Arkansas (original) (raw)
Papers by Steve Lochmann
Journal of the Southeastern Association of Fish and Wildlife Agencies, 2010
Journal of Applied Ichthyology, Mar 22, 2016
Summary Local adaptation may cause thermal tolerance to vary between nearby but distinct populati... more Summary Local adaptation may cause thermal tolerance to vary between nearby but distinct populations of a species. During the summer of 2013, alligator gar Atractosteus spatula spawned from broodstock collected from three populations within the Mississippi River drainage separated by a 5° latitudinal gradient were acclimated to three temperatures (25, 30, and 35°C). Ten fish from each population were acclimated at each temperature. CTMax was determined at each temperature for each population, using five fish for each population-acclimation temperature pairing. CTMax for each population-acclimation temperature pairing was compared using two-factor anova. CTMax increased significantly with acclimation temperature (F2,40 = 600.5, P < 0.001) but population had no significant effect (F2,40 = 1.882, P = 0.166). Temperature tolerance appears to be consistent across populations of alligator gar, with no evidence of local adaptation.
Journal of the Southeastern Association of Fish and Wildlife Agencies, 2020
Journal of the Southeastern Association of Fish and Wildlife Agencies, 2005
Abstract: Fisheries managers and anglers are concerned about the effects that increas-ing over-wi... more Abstract: Fisheries managers and anglers are concerned about the effects that increas-ing over-wintering populations of piscivorous double-crested cormorants Phalacro-corax auritus have on sport fishes across North America. We estimated the mortality of the largemouth ...
North American Journal of Aquaculture, Apr 1, 2003
A new method for surveying and comparing the prevalence of drainage ditches on aquaculture farms ... more A new method for surveying and comparing the prevalence of drainage ditches on aquaculture farms was tested with blocks of ponds on six baitfish farms in Arkansas. The method used a global positioning system, farm maps, and descriptive statistics to illustrate the relation of pond acreage to drainage ditch length. The distributions of ditch lengths and proportions of pond acreage
Canadian Journal of Fisheries and Aquatic Sciences, 1997
In November and December 1992, Atlantic cod (Gadus morhua) larvae were most abundant at a converg... more In November and December 1992, Atlantic cod (Gadus morhua) larvae were most abundant at a convergent front located at the periphery of a well-mixed gyrelike water mass rotating near the crest of Western Bank (outer Scotian Shelf). Zooplankton wet biomass and plankton abundance (272 and 529 µm size-classes) were also higher in the frontal region relative to the adjacent water masses. We used the frontal feature to test the hypothesis that larvae in frontal regions are in better condition than larvae elsewhere. No significant differences in triacylglycerol content (an index of nutritional condition), Fulton's K condition index, nor in the daylight feeding ratio were found between larvae in the frontal region and those in the adjacent waters. The convergent front acted as a larval collector, but exchange with other water masses eliminated measurable differences in larval condition. Our observations indicate that physically driven retention, not differential mortality (approximated by condition), was responsible for high abundances of cod larvae at this front. Résumé : En novembre et décembre 1992, les larves de morue (Gadus morhua) étaient les plus abondantes dans un front convergent situé à la périphérie d'une masse d'eau bien brassée en rotation, semblable à un tourbillon, près de la crête du banc Western (plate-forme Scotian extérieure). La biomasse humide de zooplancton et l'abondance du plancton (classes de taille de 272 et 529 µm) étaient également plus élevées dans la région frontale par rapport aux masses d'eau adjacentes. Nous avons utilisé la caractéristique frontale pour vérifier l'hypothèse que les larves dans les régions frontales sont en meilleur état physique que les larves vivant ailleurs. Aucune différence statistiquement significative dans la teneur en triacylglycérol (un indice de l'état nutritionnel) dans l'indice K de l'état physique de Fulton ni dans le rapport d'alimentation à la lumière naturelle n'a été observée entre les larves vivant dans la région frontale et celles qui vivent dans les eaux adjacentes. Le front convergent a agi comme collecteur de larves, mais l'échange avec d'autres masses d'eau a éliminé les différences mesurables touchant l'état des larves. Nos observations ont indiqué que la rétention à motivation physique, et non la mortalité différentielle (telle qu'établie de manière approximative par l'état), était responsable de l'abondance élevée de morues dans ce front. [Traduit par la Rédaction]
North American Journal of Fisheries Management
Population parameter estimates from mark-recapture studies are dependent on individuals retaining... more Population parameter estimates from mark-recapture studies are dependent on individuals retaining marks or tags. Therefore, tag retention estimates are needed for different tag types and anatomical tagging locations. Few studies have empirically quantified the bias from tag retention on fish population parameters that are derived from mark-recapture studies. We examined differences in retention between T-bar anchor tags and PIT tags as well as among digitalcommons.unl.edu
Supplemental stocking of sport fish has been an important management tool used by fisheries manag... more Supplemental stocking of sport fish has been an important management tool used by fisheries management agencies, but published accounts of stocking success are infrequent. Both black crappie (Pomoxis nigromaculatus) and white crappie (P. annularis) have been stocked throughout the southeastern United States with over one million stocked annually in Arkansas alone. Stocking contribution was determined for six impoundments that ranged in size from 58 to 503 ha. In October 2010 and 2011, crappies were marked with oxytetracycline hydrochloride and stocked at rates that ranged from 53 to 246 fish ha–1. Age-0 crappies were collected using trap nets each month for three months following the 2010 stocking but size selective gear bias precluded accurate short-term contribution estimates. Trap net collections in 2011 and 2012 produced no marked age-1 crappies in any impoundment. Low stocking contribution may be related to a combination of the presence of a strong natural year class, high mort...
North American Journal of Aquaculture, 2005
Recent changes in techniques for producing farm‐raised baitfish include spawning and hatching ind... more Recent changes in techniques for producing farm‐raised baitfish include spawning and hatching indoors, advances that provide better control over these steps during the production cycle. However, developing embryos experience different conditions indoors than in the traditional outdoors pond production technique. Stress during embryological development can result in small random differences between the left and right sides of a bilateral trait. For characters influenced by the environment, the degree of asymmetry can be a measure of the level of stress experienced during embryological development. Asymmetry was compared in morphological characters between two groups of golden shiners Notemigonus crysoleucas representing indoor and outdoor spawning and hatching techniques. Relative weight was also compared in fingerlings produced by the two techniques. There were no differences in asymmetry between the two groups for seven characters. Two characters were significantly more asymmetric in the group produced indoors, but one character was significantly more asymmetric in the group produced outdoors. Relative weight did not differ between the two groups. Based on the assumption that these characters are influenced by the environment and on observed similarities in asymmetry and relative weight, no consistent differences in embryological stress resulting from the two different production techniques were found.
Environmental Toxicology and Chemistry, 2006
Fluctuating asymmetry (FA; small, random differences between the left and right sides of a bilate... more Fluctuating asymmetry (FA; small, random differences between the left and right sides of a bilateral character) has been related to embryological stress during development. Some populations exhibit positive relations between FA and exposure to toxicants during development. The United States has agreed to demilitarize chemical warfare agents in accordance with the Chemical Weapons Convention Treaty. Isopropyl methylphosphonic acid (IMPA), the main hydrolysis product of sarin, could be introduced accidentally into the environment during demilitarization. The present study examined the use of FA as a biomarker of developmental stress caused by sublethal exposures to IMPA. A suite of morphometric and meristic traits were measured in two fish species exposed to IMPA. Significant differences were found in composite FA among groups of channel catfish (Ictalurus punctatus) exposed to sublethal concentrations of IMPA during development. No differences were found in composite FA among groups of golden shiner (Notemigonus crysoleucas) exposed to IMPA. No relation was found between individual relative condition and FA in channel catfish or golden shiner.
Environmental Biology of Fishes, 2020
The Strawberry Darter Etheostoma fragi is endemic to the Strawberry River drainage in northcentra... more The Strawberry Darter Etheostoma fragi is endemic to the Strawberry River drainage in northcentral Arkansas, where its distribution and status have not been assessed since the mid-1990s. A status survey was conducted during the summers of 2015 and 2016. Sixty-four sites were sampled (32 each summer) within the Strawberry River drainage. Sites were surveyed 4 times each using a kick-seine. A total of 236 E. fragi were observed during the study. E. fragi were observed at 24 of 64 sites, including 15 tributary and 9 main stem sites. Strawberry Darters were observed at sites with a median (range) dissolved oxygen of 9.2 (5.7-11.9) mg/L, median stream flow of 0.2 (0.1-0.7) m/s, median pH of 8.1 (6.7-9.4), median water temperature of 22.0 (13.9-29.3)°C, and median depth of 0.2 (0.1-0.7) m. Presence/absence data were analyzed with occupancy modeling, which estimates informed occupancy rate (hereafter, occupancy) and probability of detection. The drainage-wide occupancy (± SE) was 0.41 ± 0.06 and the probability of detection was 0.56 ± 0.06. A reach covariate model fit our data the best (209.81 AIC c). This model estimated an occupancy of 0.54 ± 0.09 and a probability of detection of 0.64 ± 0.06 in the upper reach, an occupancy of 0.20 ± 0.11 and a probability of detection of 0.51 ± 0.17 in the middle reach, and an occupancy of 0.39 ± 0.31 and a probability of detection of 0.19 ± 0.16 in the lower reach The drainage-wide occupancy was lower (0.32 difference) than an occupancy based on historical data (0.73 ± 0.11). These results suggest a decline in the status of E. fragi and justify conservation measures to preserve this species.
North American Journal of Fisheries Management
Environmental Particles, 2018
Stocking fish, regulating harvest and improving habitat are three common management tools. Manage... more Stocking fish, regulating harvest and improving habitat are three common management tools. Managers stock fish into new lakes to create fishing opportunities or into renovated lakes following a managed fish kill. Managers also stock fish to supplement natural production. Stock enhancement is when a manager puts fish from a hatchery into a lake or stream where a population of this fish already exists. This document is a review of the practice of largemouth bass stock enhancement. Stock enhancement of largemouth
Environmental Particles, 2018
North American Journal of Aquaculture, 2006
... 19962. Baird, DJ, Beveridge, MCM, Kelly, LA and Muir, JF, eds. 1996. ... [Web of Science ®], ... more ... 19962. Baird, DJ, Beveridge, MCM, Kelly, LA and Muir, JF, eds. 1996. ... [Web of Science ®], [CSA] View all references). Other common names for this insecticide are Triclorfon (Brandal and Egidius 19794. Brandal, PO and Egidius, E. 1979. ...
Journal of the World Aquaculture Society, 2004
Effluents from aquaculture facilities vary between species and among production systems. Drainage... more Effluents from aquaculture facilities vary between species and among production systems. Drainage ditches commonly convey effluents from central Arkansas baitfish ponds. Ditches could potentially reduce suspended solids prior to effluent release into receiving streams through settling. We characterized suspended solids in effluents from baitfish ponds and evaluated changes in suspended solids in drainage ditches. We also characterized drainage ditches based on width, depth, slope, and percent vegetation cover. Average (2 SD) total suspended solids (TSS) at the point of discharge was 52 (2 41) mi&, while volatile suspended solids (VSS) averaged 22 (2 23) m&. Screening effluents did little to alter their composition. Approximately 76% of TSS were less than 5 pm. There were no significant changes in effluent solids along drainage ditches 100 m from the point of discharge and no significant correlations between ditch .characteristics and changes in either TSS or VSS. Existing ditches are quite variable and are not necessarily effective in removing solids present in baitfish effluents. Screening and use of ditches as settling basins seem impractical for effluent treatment given the characteristics of solids in baitfish eftluents.
Journal of the World Aquaculture Society, 2004
Scientific information on baitfish effluents is important to provide a basis for the development ... more Scientific information on baitfish effluents is important to provide a basis for the development of appropriate and cost-effective management practices that minimize environmental impacts. Effluents from 10 commercial golden shiner Notemigonus crysoleucus ponds in central Arkansas were sampled December 2000 through June 2001. Grab samples of the first and last 10% of pond volume were collected during intentional draining events. Effluents were sampled as they exited pond drainpipes and at the ends of drainage ditches just prior to stream discharge. Concurrent receiving stream samples were collected upstream and downstream of the discharge point. Total nitrogen (TN), total phosphorus (TP), 5-d biochemical oxygen demand (BOD,), and total suspended solids (TSS) of each sample were measured. Mean whole effluent concentrations for the first 10% were 36 mg TSSL, 9 mg/L BOD5, 2 mg TNL, and 0.5 mg TPL. The water quality of the first and last 10% of pond effluent were not significantly different (P c 0.05). Filtering effluents through a 5-pm mesh screen did not significantly reduce nutrient concentrations. Serial fractionation of effluents resulted in small but significant decreases in TSS concentrations in samples filtered through the 10, 8, and 5-pw meshes (P c 0.05). Eftluent discharge through farm ditches generally did not improve effluent water quality. Effluents collected at ditch ends were significantly less than drainpipe samples in BOD, concentrations only (P < 0.05). Limited data on receiving stream water quality indicated that only TP concentrations were greater in pond effluents than in receiving streams. Overall, baitfish pond effluents are similar in composition to effluents of other phytoplankton-based pond production systems.
Fisheries Oceanography, 1998
Gut contents were obtained from 1406 cod larvae from 94 stations in seven water masses related to... more Gut contents were obtained from 1406 cod larvae from 94 stations in seven water masses related to a gyre around Western Bank, Scotian Shelf, 22 November± 16 December 1992. Initial samples were from: wellmixed water over the bank crest (CW); a surrounding convergent FRONT; relatively cold, fresh water (CFW) largely east of CW; warmer, salty water (WSW) west of CW and FRONT. After a storm on 3±6 December, samples were from CW and CFW displaced southeast on the bank and, after further winds 11±12 December, from CW displaced northwest off the bank. Zooplankton biomass (300±333 lm mesh, mostly Calanus copepodids) did not differ among water masses, but larval concentrations were signi®cantly higher in FRONT than elsewhere. The small-copepod diets of larvae varied among water masses, partly attributable to larval growth during the sampling period. Numbers of prey in guts, and indices of fullness and digestion, varied among water masses. More reliably, after ANCOVAs signi®cant independent variables were: overwhelmingly time of day (maximum prey numbers and fullness at $19:00) and larval size; water mass; weaker interactions of the above among themselves and with sample depth and date; a very weak negative turbulence-index effect on gut prey numbers in depth-strati®ed samples. After ANCOVAs, larvae from prestorm CW had signi®cantly higher prey numbers and fullness than did those from FRONT, WSW, and CFW. Larvae in CFW were signi®cantly fuller when sampled closer to sites of former CW after the storm. Although numbers of prey in larvae advected off the bank in CW decreased signi®cantly, prey averaged larger, so that gut fullness did not decrease. We conclude that larvae were best fed in the`centre' of the Western Bank gyre, but not greatly affected by subsequent displacement off the bank.
Journal of the Southeastern Association of Fish and Wildlife Agencies, 2010
Journal of Applied Ichthyology, Mar 22, 2016
Summary Local adaptation may cause thermal tolerance to vary between nearby but distinct populati... more Summary Local adaptation may cause thermal tolerance to vary between nearby but distinct populations of a species. During the summer of 2013, alligator gar Atractosteus spatula spawned from broodstock collected from three populations within the Mississippi River drainage separated by a 5° latitudinal gradient were acclimated to three temperatures (25, 30, and 35°C). Ten fish from each population were acclimated at each temperature. CTMax was determined at each temperature for each population, using five fish for each population-acclimation temperature pairing. CTMax for each population-acclimation temperature pairing was compared using two-factor anova. CTMax increased significantly with acclimation temperature (F2,40 = 600.5, P < 0.001) but population had no significant effect (F2,40 = 1.882, P = 0.166). Temperature tolerance appears to be consistent across populations of alligator gar, with no evidence of local adaptation.
Journal of the Southeastern Association of Fish and Wildlife Agencies, 2020
Journal of the Southeastern Association of Fish and Wildlife Agencies, 2005
Abstract: Fisheries managers and anglers are concerned about the effects that increas-ing over-wi... more Abstract: Fisheries managers and anglers are concerned about the effects that increas-ing over-wintering populations of piscivorous double-crested cormorants Phalacro-corax auritus have on sport fishes across North America. We estimated the mortality of the largemouth ...
North American Journal of Aquaculture, Apr 1, 2003
A new method for surveying and comparing the prevalence of drainage ditches on aquaculture farms ... more A new method for surveying and comparing the prevalence of drainage ditches on aquaculture farms was tested with blocks of ponds on six baitfish farms in Arkansas. The method used a global positioning system, farm maps, and descriptive statistics to illustrate the relation of pond acreage to drainage ditch length. The distributions of ditch lengths and proportions of pond acreage
Canadian Journal of Fisheries and Aquatic Sciences, 1997
In November and December 1992, Atlantic cod (Gadus morhua) larvae were most abundant at a converg... more In November and December 1992, Atlantic cod (Gadus morhua) larvae were most abundant at a convergent front located at the periphery of a well-mixed gyrelike water mass rotating near the crest of Western Bank (outer Scotian Shelf). Zooplankton wet biomass and plankton abundance (272 and 529 µm size-classes) were also higher in the frontal region relative to the adjacent water masses. We used the frontal feature to test the hypothesis that larvae in frontal regions are in better condition than larvae elsewhere. No significant differences in triacylglycerol content (an index of nutritional condition), Fulton's K condition index, nor in the daylight feeding ratio were found between larvae in the frontal region and those in the adjacent waters. The convergent front acted as a larval collector, but exchange with other water masses eliminated measurable differences in larval condition. Our observations indicate that physically driven retention, not differential mortality (approximated by condition), was responsible for high abundances of cod larvae at this front. Résumé : En novembre et décembre 1992, les larves de morue (Gadus morhua) étaient les plus abondantes dans un front convergent situé à la périphérie d'une masse d'eau bien brassée en rotation, semblable à un tourbillon, près de la crête du banc Western (plate-forme Scotian extérieure). La biomasse humide de zooplancton et l'abondance du plancton (classes de taille de 272 et 529 µm) étaient également plus élevées dans la région frontale par rapport aux masses d'eau adjacentes. Nous avons utilisé la caractéristique frontale pour vérifier l'hypothèse que les larves dans les régions frontales sont en meilleur état physique que les larves vivant ailleurs. Aucune différence statistiquement significative dans la teneur en triacylglycérol (un indice de l'état nutritionnel) dans l'indice K de l'état physique de Fulton ni dans le rapport d'alimentation à la lumière naturelle n'a été observée entre les larves vivant dans la région frontale et celles qui vivent dans les eaux adjacentes. Le front convergent a agi comme collecteur de larves, mais l'échange avec d'autres masses d'eau a éliminé les différences mesurables touchant l'état des larves. Nos observations ont indiqué que la rétention à motivation physique, et non la mortalité différentielle (telle qu'établie de manière approximative par l'état), était responsable de l'abondance élevée de morues dans ce front. [Traduit par la Rédaction]
North American Journal of Fisheries Management
Population parameter estimates from mark-recapture studies are dependent on individuals retaining... more Population parameter estimates from mark-recapture studies are dependent on individuals retaining marks or tags. Therefore, tag retention estimates are needed for different tag types and anatomical tagging locations. Few studies have empirically quantified the bias from tag retention on fish population parameters that are derived from mark-recapture studies. We examined differences in retention between T-bar anchor tags and PIT tags as well as among digitalcommons.unl.edu
Supplemental stocking of sport fish has been an important management tool used by fisheries manag... more Supplemental stocking of sport fish has been an important management tool used by fisheries management agencies, but published accounts of stocking success are infrequent. Both black crappie (Pomoxis nigromaculatus) and white crappie (P. annularis) have been stocked throughout the southeastern United States with over one million stocked annually in Arkansas alone. Stocking contribution was determined for six impoundments that ranged in size from 58 to 503 ha. In October 2010 and 2011, crappies were marked with oxytetracycline hydrochloride and stocked at rates that ranged from 53 to 246 fish ha–1. Age-0 crappies were collected using trap nets each month for three months following the 2010 stocking but size selective gear bias precluded accurate short-term contribution estimates. Trap net collections in 2011 and 2012 produced no marked age-1 crappies in any impoundment. Low stocking contribution may be related to a combination of the presence of a strong natural year class, high mort...
North American Journal of Aquaculture, 2005
Recent changes in techniques for producing farm‐raised baitfish include spawning and hatching ind... more Recent changes in techniques for producing farm‐raised baitfish include spawning and hatching indoors, advances that provide better control over these steps during the production cycle. However, developing embryos experience different conditions indoors than in the traditional outdoors pond production technique. Stress during embryological development can result in small random differences between the left and right sides of a bilateral trait. For characters influenced by the environment, the degree of asymmetry can be a measure of the level of stress experienced during embryological development. Asymmetry was compared in morphological characters between two groups of golden shiners Notemigonus crysoleucas representing indoor and outdoor spawning and hatching techniques. Relative weight was also compared in fingerlings produced by the two techniques. There were no differences in asymmetry between the two groups for seven characters. Two characters were significantly more asymmetric in the group produced indoors, but one character was significantly more asymmetric in the group produced outdoors. Relative weight did not differ between the two groups. Based on the assumption that these characters are influenced by the environment and on observed similarities in asymmetry and relative weight, no consistent differences in embryological stress resulting from the two different production techniques were found.
Environmental Toxicology and Chemistry, 2006
Fluctuating asymmetry (FA; small, random differences between the left and right sides of a bilate... more Fluctuating asymmetry (FA; small, random differences between the left and right sides of a bilateral character) has been related to embryological stress during development. Some populations exhibit positive relations between FA and exposure to toxicants during development. The United States has agreed to demilitarize chemical warfare agents in accordance with the Chemical Weapons Convention Treaty. Isopropyl methylphosphonic acid (IMPA), the main hydrolysis product of sarin, could be introduced accidentally into the environment during demilitarization. The present study examined the use of FA as a biomarker of developmental stress caused by sublethal exposures to IMPA. A suite of morphometric and meristic traits were measured in two fish species exposed to IMPA. Significant differences were found in composite FA among groups of channel catfish (Ictalurus punctatus) exposed to sublethal concentrations of IMPA during development. No differences were found in composite FA among groups of golden shiner (Notemigonus crysoleucas) exposed to IMPA. No relation was found between individual relative condition and FA in channel catfish or golden shiner.
Environmental Biology of Fishes, 2020
The Strawberry Darter Etheostoma fragi is endemic to the Strawberry River drainage in northcentra... more The Strawberry Darter Etheostoma fragi is endemic to the Strawberry River drainage in northcentral Arkansas, where its distribution and status have not been assessed since the mid-1990s. A status survey was conducted during the summers of 2015 and 2016. Sixty-four sites were sampled (32 each summer) within the Strawberry River drainage. Sites were surveyed 4 times each using a kick-seine. A total of 236 E. fragi were observed during the study. E. fragi were observed at 24 of 64 sites, including 15 tributary and 9 main stem sites. Strawberry Darters were observed at sites with a median (range) dissolved oxygen of 9.2 (5.7-11.9) mg/L, median stream flow of 0.2 (0.1-0.7) m/s, median pH of 8.1 (6.7-9.4), median water temperature of 22.0 (13.9-29.3)°C, and median depth of 0.2 (0.1-0.7) m. Presence/absence data were analyzed with occupancy modeling, which estimates informed occupancy rate (hereafter, occupancy) and probability of detection. The drainage-wide occupancy (± SE) was 0.41 ± 0.06 and the probability of detection was 0.56 ± 0.06. A reach covariate model fit our data the best (209.81 AIC c). This model estimated an occupancy of 0.54 ± 0.09 and a probability of detection of 0.64 ± 0.06 in the upper reach, an occupancy of 0.20 ± 0.11 and a probability of detection of 0.51 ± 0.17 in the middle reach, and an occupancy of 0.39 ± 0.31 and a probability of detection of 0.19 ± 0.16 in the lower reach The drainage-wide occupancy was lower (0.32 difference) than an occupancy based on historical data (0.73 ± 0.11). These results suggest a decline in the status of E. fragi and justify conservation measures to preserve this species.
North American Journal of Fisheries Management
Environmental Particles, 2018
Stocking fish, regulating harvest and improving habitat are three common management tools. Manage... more Stocking fish, regulating harvest and improving habitat are three common management tools. Managers stock fish into new lakes to create fishing opportunities or into renovated lakes following a managed fish kill. Managers also stock fish to supplement natural production. Stock enhancement is when a manager puts fish from a hatchery into a lake or stream where a population of this fish already exists. This document is a review of the practice of largemouth bass stock enhancement. Stock enhancement of largemouth
Environmental Particles, 2018
North American Journal of Aquaculture, 2006
... 19962. Baird, DJ, Beveridge, MCM, Kelly, LA and Muir, JF, eds. 1996. ... [Web of Science ®], ... more ... 19962. Baird, DJ, Beveridge, MCM, Kelly, LA and Muir, JF, eds. 1996. ... [Web of Science ®], [CSA] View all references). Other common names for this insecticide are Triclorfon (Brandal and Egidius 19794. Brandal, PO and Egidius, E. 1979. ...
Journal of the World Aquaculture Society, 2004
Effluents from aquaculture facilities vary between species and among production systems. Drainage... more Effluents from aquaculture facilities vary between species and among production systems. Drainage ditches commonly convey effluents from central Arkansas baitfish ponds. Ditches could potentially reduce suspended solids prior to effluent release into receiving streams through settling. We characterized suspended solids in effluents from baitfish ponds and evaluated changes in suspended solids in drainage ditches. We also characterized drainage ditches based on width, depth, slope, and percent vegetation cover. Average (2 SD) total suspended solids (TSS) at the point of discharge was 52 (2 41) mi&, while volatile suspended solids (VSS) averaged 22 (2 23) m&. Screening effluents did little to alter their composition. Approximately 76% of TSS were less than 5 pm. There were no significant changes in effluent solids along drainage ditches 100 m from the point of discharge and no significant correlations between ditch .characteristics and changes in either TSS or VSS. Existing ditches are quite variable and are not necessarily effective in removing solids present in baitfish effluents. Screening and use of ditches as settling basins seem impractical for effluent treatment given the characteristics of solids in baitfish eftluents.
Journal of the World Aquaculture Society, 2004
Scientific information on baitfish effluents is important to provide a basis for the development ... more Scientific information on baitfish effluents is important to provide a basis for the development of appropriate and cost-effective management practices that minimize environmental impacts. Effluents from 10 commercial golden shiner Notemigonus crysoleucus ponds in central Arkansas were sampled December 2000 through June 2001. Grab samples of the first and last 10% of pond volume were collected during intentional draining events. Effluents were sampled as they exited pond drainpipes and at the ends of drainage ditches just prior to stream discharge. Concurrent receiving stream samples were collected upstream and downstream of the discharge point. Total nitrogen (TN), total phosphorus (TP), 5-d biochemical oxygen demand (BOD,), and total suspended solids (TSS) of each sample were measured. Mean whole effluent concentrations for the first 10% were 36 mg TSSL, 9 mg/L BOD5, 2 mg TNL, and 0.5 mg TPL. The water quality of the first and last 10% of pond effluent were not significantly different (P c 0.05). Filtering effluents through a 5-pm mesh screen did not significantly reduce nutrient concentrations. Serial fractionation of effluents resulted in small but significant decreases in TSS concentrations in samples filtered through the 10, 8, and 5-pw meshes (P c 0.05). Eftluent discharge through farm ditches generally did not improve effluent water quality. Effluents collected at ditch ends were significantly less than drainpipe samples in BOD, concentrations only (P < 0.05). Limited data on receiving stream water quality indicated that only TP concentrations were greater in pond effluents than in receiving streams. Overall, baitfish pond effluents are similar in composition to effluents of other phytoplankton-based pond production systems.
Fisheries Oceanography, 1998
Gut contents were obtained from 1406 cod larvae from 94 stations in seven water masses related to... more Gut contents were obtained from 1406 cod larvae from 94 stations in seven water masses related to a gyre around Western Bank, Scotian Shelf, 22 November± 16 December 1992. Initial samples were from: wellmixed water over the bank crest (CW); a surrounding convergent FRONT; relatively cold, fresh water (CFW) largely east of CW; warmer, salty water (WSW) west of CW and FRONT. After a storm on 3±6 December, samples were from CW and CFW displaced southeast on the bank and, after further winds 11±12 December, from CW displaced northwest off the bank. Zooplankton biomass (300±333 lm mesh, mostly Calanus copepodids) did not differ among water masses, but larval concentrations were signi®cantly higher in FRONT than elsewhere. The small-copepod diets of larvae varied among water masses, partly attributable to larval growth during the sampling period. Numbers of prey in guts, and indices of fullness and digestion, varied among water masses. More reliably, after ANCOVAs signi®cant independent variables were: overwhelmingly time of day (maximum prey numbers and fullness at $19:00) and larval size; water mass; weaker interactions of the above among themselves and with sample depth and date; a very weak negative turbulence-index effect on gut prey numbers in depth-strati®ed samples. After ANCOVAs, larvae from prestorm CW had signi®cantly higher prey numbers and fullness than did those from FRONT, WSW, and CFW. Larvae in CFW were signi®cantly fuller when sampled closer to sites of former CW after the storm. Although numbers of prey in larvae advected off the bank in CW decreased signi®cantly, prey averaged larger, so that gut fullness did not decrease. We conclude that larvae were best fed in the`centre' of the Western Bank gyre, but not greatly affected by subsequent displacement off the bank.