Differences in early developmental rate and yolk conversion efficiency in offspring of trout with alternative life histories          下载免费PDF全文

Travis E. Van Leeuwen  Shaun S. Killen  Neil B. Metcalfe  Colin E. Adams 《Ecology of Freshwater Fish》2017,26(3):371-382

Partial migration, in which some individuals of a population migrate while other individuals remain resident, is generally associated with ontogenetic shifts to better feeding areas or as a response to environmental instability, but its underlying mechanisms remain relatively unknown. Brown trout (Salmo trutta) exhibit partial migration, with some individuals remaining in freshwater (freshwater resident) while others undertake an anadromous migration, where they spend time at sea before returning to breed in freshwater (migrant). We reared full‐sibling groups of offspring from freshwater‐resident and anadromous brown trout from the same catchment in the laboratory under common garden conditions to examine potential differences in their early development. Freshwater‐resident parents produced eggs that were slower to hatch than those of anadromous parents, but freshwater‐resident offspring were quicker to absorb their yolk and reach the stage of exogenous feeding. Their offspring also had a higher conversion efficiency from the egg stage to the start of exogenous feeding (so were larger by the start of the fry stage) than did offspring from anadromous parents despite no difference in standard metabolic rate, maximal metabolic rate or aerobic scope. Given these differences in early development, we discuss how the migration history of the parents might influence the migration probability of the offspring.  相似文献   

Demonstration of alternative feeds for the Pacific white shrimp, Litopenaeus vannamei, reared in low salinity waters of west Alabama     

Luke A Roy  ré Bordinhon  Daranee Sookying  D Allen Davis  Travis W Brown  & Gregory N Whitis 《Aquaculture Research》2009,40(4):496-503

The replacement of marine proteins with vegetable proteins or terrestrial animal byproducts in aquaculture diets has been gaining momentum. This study examines the viability of replacing fish meal in shrimp production diets with alternative protein sources (combinations of vegetable proteins) in inland low salinity waters of west Alabama. The test diets were formulated to contain 36% protein and 8% lipid. The basal diet contained 10% fish meal. The fish meal was then replaced (on a weight to weight basis) with poultry meal (PM), pea meal or distiller's dried grain with solubles (DDGS). Two separate experiments (laboratory trial and farm trial) were devised to test the efficacy of the diets for Litopenaeus vannamei reared in low salinity waters. The laboratory trial was conducted at the E. W. Shell Fisheries Research Station in Auburn, Alabama, USA, whereas the farm trial examined the same diets in an outdoor flow-through system at a low salinity shrimp farm in west Alabama. Results indicate no significant differences in shrimp growth, weight gain, survival or feed conversion ratio among dietary treatments, suggesting that PM, pea meal and DDGS can serve as alternatives to fish meal as a protein source for shrimp reared in low salinity environments.  相似文献   

Space use and inferred spawning activity of three exploited gamefish species on a large artificial reef     

Ryan K. Logan  Christopher G. Lowe 《Fisheries Management and Ecology》2019,26(6):558-569

Intense fishing pressure has led to changes in species composition, demography and the over‐exploitation of many coastal fishes. To restore populations, artificial reefs (ARs) are used with the assumption that new habitat will increase fish productivity. Kelp bass (Paralabrax clathratus), barred sand bass (P. nebulifer) and California sheephead (Semicossyphus pulcher) are three important recreational gamefish species in southern California. Home ranging behaviour, space use and spawning‐related activity of these three species were quantified on a large AR. Kelp bass used the largest amount of area, but space use was similar among species. While no spawning behaviour could be determined for sheephead, kelp bass exhibited two different activity patterns during spawning months and barred sand bass migrated (indicative of spawning). Results of this study indicate that this large AR is providing suitable habitat for these species, and spawning‐related activity could be a sign that this AR is meeting essential life history demands.  相似文献   

A novel attempt at artificial spawning of captive bonefish (Albula spp.)     

Sahar Mejri  William R. Halstead  Cameron A. Luck  Christopher Robinson  Travis E. Van Leeuwen  Aaron J. Adams  Jon Shenker  Matthew J. Ajemian  Paul S. Wills 《Aquaculture Research》2019,50(9):2718-2723

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Machine vision smart sprayer for spot-application of agrochemical in wild blueberry fields     

Travis Esau  Qamar Zaman  Dominic Groulx  Aitazaz Farooque  Arnold Schumann  Young Chang 《Precision Agriculture》2018,19(4):770-788

An essential part of the wild blueberry cropping system is the proper management of agrochemical inputs including herbicides, fungicides and insecticides. A machine vision system was developed and mounted on the rear sprayer boom 0.18 m in front of the sprayer nozzles capable of targeting the agrochemical application on an as-needed basis. The three-point hitch mounted sprayer featured 27 nozzles over a 13.7 m boom width and a storage tank capacity of 1135 l. Nine digital color cameras continually take images in real-time while computer software processes the images in 0.15 s to determine the target locations where the nozzles open and spray at speeds up to 1.77 m s^?1. Two wild blueberry fields in central Nova Scotia were selected for smart sprayer performance testing with spot-application (SA) of agrochemical as compared to control and uniform application techniques. Chateau^® herbicide was applied in a field with an infestation of hair cap moss. Spray droplet comparison showed moss patches were properly targeted using the smart sprayer. SA provided the same coverage performance as compared to uniform on the moss targets with herbicide application savings of 78.5% using the smart sprayer. Harvestable yield results were similar for all application tracks. TruPhos Magnesium and ZincMax foliar fertilizers were tank mixed with Bravo^® and Proline^® fungicides and applied to compare the difference of SA, control and uniform application. Results showed SA of foliar fertilizer and fungicide led to less premature leaf drop and increased the blueberry stem height, number of branches, stem diameter and fruit buds. SA of foliar fertilizer and fungicide also increased the percent of healthy wild blueberry plants by 57.8% and the harvestable yield by 137.8%. Fungicide application savings using the smart sprayer for SA were 11.6%.  相似文献   

Site fidelity,survival and conservation options for the threatened flapper skate (Dipturus cf. intermedia)          下载免费PDF全文

Francis Neat  Cecilia Pinto  Ian Burrett  Lewis Cowie  Justin Travis  James Thorburn  Fiona Gibb  Peter J. Wright 《水产资源保护:海洋与淡水生态系统》2015,25(1):6-20

Prevalence of Concentrated Flow Paths in Agricultural Fields in Southern Illinois     

Prabisha Shrestha  Karl W. J. Williard  Jon E. Schoonover  Logan Park 《Water, air, and soil pollution》2018,229(6):198

Literature on prevalence of concentrated flow paths (CPFs) in agricultural fields are limited at field scale with only few studies that address occurrence of CFPs at large geographic extent. This study used high-resolution Light Detection and Ranging (LiDAR) data to identify CFPs in agricultural fields and calculate the percentage of the fields drained by CFPs at a county scale. In 389 agricultural fields across Jackson County, southern Illinois, this study also investigated the association between field characteristics and CFP formation using multiple regression and CART analysis. The mean number of CFPs in a field was 5 with a minimum of 0 and maximum of 17 CFPs. The majority of the CFPs fell under the large category for CFP length and drainage area that corresponds with high mean percent (81%) of field area drained by the CFPs. Further, 85% of the fields had more than 70% of their area drained by CFPs. The multiple regression and CART analysis showed slope as an important factor influencing CFP characteristics such as number of CFPs and CFP length. Both analyses also indicated physical soil properties such as bulk density, soil erodibility factor, saturated hydraulic conductivity, LS factor, organic matter, and percent sand were also predictors of the CFP characteristics. However, these factors explained only 2 to 12% of the variation observed. The significant presence of CFP’s has important implications for water quality since current conservation practices such as riparian buffers were not designed to address concentrated flow from agricultural fields.  相似文献   

Clinical Phenotype of Musladin‐Lueke Syndrome in 2 Beagles          下载免费PDF全文

R.A. Packer  M.A. Logan  L.T. Guo  S.S. Apte  H. Bader  D.P. O'Brien  G. Johnson  G.D. Shelton 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2017,31(2):532-538

Musladin‐Lueke syndrome (MLS), previously termed Chinese Beagle syndrome, is an autosomal‐recessive connective tissue disorder characterized by extensive fibrosis of the skin and joints that was first identified in Beagles in the 1970s. Recent research identified a founder mutation (c.660C>T; p.R221C) in the ADAMTSL2 gene in Beagles with MLS. Here, we report the detailed clinical phenotype and laboratory findings in 2 Beagles affected with MLS. We discuss these findings in relation to the human disorder geleophysic dysplasia (GD), which also arises from recessive ADAMTSL2 mutations, and recent findings in Adamtsl2‐deficient mice.  相似文献   

Archaeology. Archaeologists see big promise in going molecular     

Travis J 《Science (New York, N.Y.)》2010,330(6000):28-29

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Systemic granuloma observed in Atlantic salmon Salmo salar raised to market size in a freshwater recirculation aquaculture system          下载免费PDF全文

Christopher Good  David P Marancik  Timothy J Welch  Travis May  John Davidson  Steven Summerfelt 《Aquaculture Research》2016,47(11):3679-3683

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