Introduction to Aquaculture Effluents: overview of EPA guidelines and standards and BMPs for ponds, raceways, and recycle systems

Aquaculture is the production of aquatic organisms, both plant and animal under controlled or semi-controlled conditions. The “controlled or semi-controlled conditions” distinguishes aquaculture from traditional “hunt-and-capture” fishing of wild stocks of marine and freshwater fish, shrimp, and shellfish. The combination of world aquaculture and commercial catches (wild stocks) have grown from 98.6 million metric tons (mmt) in 1990 to 126.2 mmt in 1999, but in 1990 aquaculture was only 13.2% of the total compared with 26.4% in 1999

A White Paper on the status and needs of walleye aquaculture in the North Central Region

Walleye has been recognized as a species with substantial aquaculture potential in the National Aquaculture Plan of 1983 (Joint Subcommittee on Aquaculture 1983). NCRAC\u27s Industry Advisory Council and the Technical Committee, have also identified walleye one of the most promising species for aquaculture in the North Central Region (NCR) since the first joint meeting, May 1988

Proceedings: Aquaculture Effluents: Overview of EPA Guidelines and Standards and BMPs for Ponds, Raceways, and Recycle Culture Systems

Aquaculture is the production of aquatic organisms, both plant and animal under controlled or semi-controlled conditions. The “controlled or semi-controlled conditions” distinguishes aquaculture from traditional “hunt-and-capture” fishing of wild stocks of marine and freshwater fish, shrimp, and shellfish. The combination of world aquaculture and commercial catches (wild stocks) have grown from 98.6 million metric tons (mmt) in 1990 to 126.2 mmt in 1999, but in 1990 aquaculture was only 13.2% of the total compared with 26.4% in 1999

Toxicity of pesticides adsorbed to suspended sediment to larval fish in the Cedar River

How do suspended sediment and pesticides introduced into Iowa streams and rivers by erosion of agricultural soil affect warm water fish? This study looks at how chlorpyrifos, a widely used pesticide, and suspended sediment interact with each other in river water and their effects on the survival of larval walleye

Toxicity of Cedar River Water and Sediment to Larval Walleye

Although all anthropogenic stressors affecting aquatic ecosystems have not been isolated, suspended solids, sediment, and pesticides are believed to be major factors in agroecosystems. In the spring of 1998 and 1999, static 48-h tests were conducted to determine the toxicity of water and sediment collected from the Cedar River to prolarval, postlarval I, and postlarval II walleye (Sttzostedzon vitreum). River water and sediment were not more toxic to any larval stage of walleye than reference water and sediment. Cedar River sediments, suspended solids, and water were examined for occurrence of the most common herbicides and insecticides in Iowa. No pesticides were found in sediments or suspended solids, but metolachlor, desethyl atrazine, acetochlor, and parathion were detected in water samples. However, no adverse effects were observed in larval walleye exposed to Cedar River water containing these pesticides. In addition, cholinesterase (ChE) activity in postlarvae I walleye exposed to Cedar River water containing parathion was not significantly different from postlarvae I exposed to control water. At the time of the study, the results indicated that pesticides were not a threat to survival of larval walleye in the Cedar River

Assessing the Spatial Relationship Between Fixation and Foveal Specializations

Increased cone photoreceptor density, an avascular zone (FAZ), and the displacement of inner retinal neurons to form a pit are distinct features of the human fovea. As the fovea provides the majority of our vision, appreciating how these anatomical specializations are related is important for understanding foveal development, normal visual function, and retinal disease. Here we evaluated the relationship between these specializations and their location relative to the preferred retinal locus of fixation (PRL). We measured foveal pit volume, FAZ area, peak cone density, and location of the PRL in 22 subjects with normal vision using optical coherence tomography and adaptive optics scanning light ophthalmoscopy. Foveal pit volume was positively correlated with FAZ area; however, peak cone density was not correlated with pit volume. In addition, there was no systematic offset of the location of any of these specializations relative to PRL, and there was no correlation between the magnitude of the offset from PRL and the corresponding foveal specialization measurements (pit volume, FAZ area, peak cone density). The standard deviation of our PRL measurements was consistent with previous measurements of fixational stability. These data provide insight into the sequence of events during foveal development and may have implications for visual function and retinal disease

Occurrence of Ovotestes and Plasma Vitellogenin in Feral Male Fathead Minnows from Lagoons of Municipal Wastewater Treatment Facilities in Central Iowa

Since the early 1990s, endocrine disrupting compounds have been recognized as an important environmental threat. Male fish exposed to effluent from large, metropolitan municipal wastewater treatment facilities (WWTFs) have developed reproductive abnormalities including ovotestes and elevated levels of plasma vitellogenin (Vtg), a plasma protein typically produced by egg-laying females. In the summer of 2000, gonads and plasma Vtg concentrations were examined in feral male fathead minnows (Pimephales promelas) collected from lagoons of 11 small, rural municipal WWTFs and a reference site (a national wildlife refuge) in Iowa. Fathead minnows were captured in traps from five of the 33 lagoons (three per WWTF) sampled. No other fish species were captured. The five lagoons with fathead minnows were found at three WWTFs. Gonad histology indicated only one of 65 (1.5%) male fish living in the lagoons had ovotestes, which was similar to the incidence at a reference site (1 of 29, 3.4%). Plasma Vtg, however, was substantially higher in fish from four of the five lagoons than in fish from the reference site, indicating that fish in lagoons were exposed to estrogenic substances

The Role of Mechanical Injury in an Experimental Transmission of Flexibacter columnaris to Fingerling Walleye

The role of mechanical injury in transmission of Flexibacter columnaris to walleye fingerlings (Stizostedion vitreum vitreum) was investigated. Two groups (1 and 2) of 10 fish each, 7 to 9 cm total length, were exposed to a suspension of F lexibacter columnaris containing 3 X 105 cfu/ mL; fish in group 1 were injured with a scratch along their flank; fish in group 2 were not injured. Two control groups (3 and 4) of 5 fish each were exposed to a sterile broth; group 3 was injured with a scratch and group 4 was not. In 72 h, morbidity was obvious in 7 of 10 fish in group 1, 1 of 10 in group 2, but none of the controls (groups 3 and 4). F. columnaris was isolated on cytophaga agar from swabs taken from moribund fish in groups 1 and 2, but not from healthy fish in any groups. In moribund fish, of group 1, F. columnaris was isolated from skin lesions of all 7 fish, from the gills of 2 fish, and from the kidney of 1 fish. Tissue damage in moribund fish in group 1 included extensive necrosis of the skin and underlying musculature; gill damage included epithelial separation, infarcts, and, in the most severe case, a secondary fungal infection. The inflammatory response included a substantial increase in relative abundance of lymphocytes in infected fish compared with healthy fish. In a plate culture, antibiotic sensitivity test, oxytetracycline was the most effective among the seven antibacterials examined

Microscopic Inner Retinal Hyper-reflective Phenotypes in Retinal and Neurologic Disease

Purpose. We surveyed inner retinal microscopic features in retinal and neurologic disease using a reflectance confocal adaptive optics scanning light ophthalmoscope (AOSLO). Methods. Inner retinal images from 101 subjects affected by one of 38 retinal or neurologic conditions and 11 subjects with no known eye disease were examined for the presence of hyper-reflective features other than vasculature, retinal nerve fiber layer, and foveal pit reflex. The hyper-reflective features in the AOSLO images were grouped based on size, location, and subjective texture. Clinical imaging, including optical coherence tomography (OCT), scanning laser ophthalmoscopy, and fundus photography was analyzed for comparison. Results. Seven categories of hyper-reflective inner retinal structures were identified, namely punctate reflectivity, nummular (disc-shaped) reflectivity, granular membrane, waxy membrane, vessel-associated membrane, microcysts, and striate reflectivity. Punctate and nummular reflectivity also was found commonly in normal volunteers, but the features in the remaining five categories were found only in subjects with retinal or neurologic disease. Some of the features were found to change substantially between follow up imaging months apart. Conclusions. Confocal reflectance AOSLO imaging revealed a diverse spectrum of normal and pathologic hyper-reflective inner and epiretinal features, some of which were previously unreported. Notably, these features were not disease-specific, suggesting that they might correspond to common mechanisms of degeneration or repair in pathologic states. Although prospective studies with larger and better characterized populations, along with imaging of more extensive retinal areas are needed, the hyper-reflective structures reported here could be used as disease biomarkers, provided their specificity is studied further

The Midwest Feeds Consortium: Final Report

The strategic intent of the Midwest Feeds Consortium (MFC) was to decrease the dependence of the U.S. agriculture and aquaculture feed industries on imported marine protein meals and to increase the utilization and export of plant and animal coproduct protein meals to the international aquaculture industry. Replacement of marine meals in feeds traditionally dependent on these protein sources with grains, oilseed, and animal coproduct protein meals common to the U.S. Midwest would be accomplished through innovative, value-added ingredient processing technology. Through systematic, integrated, industry-directed research to develop ingredient composition, quality, digestibility, and economic values, the U.S. and international feed industry would then be able to rapidly incorporate the findings into their ingredient and equipment-purchasing decisions. The work described herein drew heavily upon recommendations developed by the MFC workshop, which was the first United States Department of Agriculture (USDA)-funded undertaking by the Consortium. The priority activities were industry linkages, ingredient processing, ingredient testing, and technology transfer. After the initial workshop, the Consortium underwent several changes in management structure, participants, and directions, which slowed progress considerably. In May 1997, a focus meeting was held in Des Moines, Iowa, between principal Consortium participants to modify priorities and reestablish timelines. The project reemerged with objectives designed to meet the priority issues of the project