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At least 73 records · Page 4Linked to original sources
USGS2010

Perspectives: Gene Expression in Fisheries Management

Functional genes and gene expression have been connected to physiological traits linked to effective production and broodstock selection in aquaculture, selective implications of commercial fish harvest, and adaptive changes reflected in non-commercial fish populations subject to human disturbance and climate change. Gene mapping using single nucleotide polymorphisms (SNPs) to identify functional genes, gene expression (analogue microarrays and real-time PCR), and digital sequencing technologies looking at RNA transcripts present new concepts and opportunities in support of effective and sustainable fisheries. Genomic tools have been rapidly growing in aquaculture research addressing aspects of fish health, toxicology, and early development. Genomic technologies linking effects in functional genes involved in growth, maturation and life history development have been tied to selection resulting from harvest practices. Incorporating new and ever-increasing knowledge of fish genomes is opening a different perspective on local adaptation that will prove invaluable in wild fish conservation and management. Conservation of fish stocks is rapidly incorporating research on critical adaptive responses directed at the effects of human disturbance and climate change through gene expression studies. Genomic studies of fish populations can be generally grouped into three broad categories: 1) evolutionary genomics and biodiversity; 2) adaptive physiological responses to a changing environment; and 3) adaptive behavioral genomics and life history diversity. We review current genomic research in fisheries focusing on those that use microarrays to explore differences in gene expression among phenotypes and within or across populations, information that is critically important to the conservation of fish and their relationship to humans.

Current Zoology↗
USGS2014

Susceptibility of Koi and Yellow Perch to infectious hematopoietic necrosis virus by experimental exposure

Infectious hematopoietic necrosis virus (IHNV) is a novirhabdoviral pathogen that originated in western North America among anadromous Pacific salmonids. Severe disease epidemics in the late 1970s resulting from IHNV's invasion into farmed Rainbow Trout Oncorhynchus mykiss in North America, Asia, and Europe emphasized IHNV's ability to adapt to new hosts under varying rearing conditions. Yellow Perch Perca flavescens and Koi Carp Cyprinus carpio (hereafter, “Koi”) are aquaculture-reared fish that are highly valued in sport fisheries and the ornamental fish trade, respectively, but it is unknown whether these fish species are vulnerable to IHNV infection. In this study, we exposed Yellow Perch, Koi, and steelhead (anadromous Rainbow Trout) to IHNV by intraperitoneal injection (10 6 PFU/fish) and by immersion (5.7×10 5 PFU/mL) for 7 h, and monitored fish for 28 d. The extended immersion exposure and high virus concentrations used in the challenges were to determine if the tested fish had any level of susceptibility. After experimental exposure, Yellow Perch and Koi experienced low mortality (<6%) compared with steelhead (>35%). Virus was found in dead fish of all species tested and in surviving Yellow Perch by plaque assay and quantitative reverse transcription polymerase chain reaction (qPCR), with a higher prevalence in Yellow Perch than Koi. Infectious virus was also detected in Yellow Perch out to 5 d after bath challenge. These findings indicate that Yellow Perch and Koi are highly resistant to IHNV disease under the conditions tested, but Yellow Perch are susceptible to infection and may serve as possible virus carriers.

Journal of Aquatic Animal Health↗
USGS1999

Nesting populations of double-crested cormorants in the United States and Canada

Double-crested cormorants ( Phalacrocorax auritus ) are receiving increasing attention in North America because of depredations at aquaculture facilities and alleged impacts on sport and commercial fisheries. We obtained recent (most since 1994) estimates for the number of nesting double-crested cormorants in the United States and Canada from published references and by conducting telephone interviews with State and Provincial biologists. Using published data, we also determined annual rates of change in the number of cormorants since about 1990. The estimated minimum number of nesting pairs (colonies) of double-crested cormorants was 372,000 (852). Most cormorants nested in the Interior region (68 percent). Overall, double-crested cormorants increased about 2.6 percent annually during the early 1990’s. The greatest decline (−7.9-percent annual change) was in the West Coast–Alaska region. The greatest increase (6.0-percent annual change) was for the Interior region. The increase there was primarily a consequence of a 22-percent annual increase in Ontario and U.S. States bordering the Great Lakes. These baseline population data are essential for monitoring trends in nesting populations and for developing informed management decisions. However, the completeness, quality, and timing of surveys varied substantially among jurisdictions. Population estimates and rates of change should, therefore, be used with caution. Methods and timing of future surveys should be coordinated among political jurisdictions (at least within regions) to improve accuracy of estimates and allow more meaningful comparisons of population status.

Conference Paper↗
USGS2010

Emerging viral diseases of fish and shrimp

The rise of aquaculture has been one of the most profound changes in global food production of the past 100 years. Driven by population growth, rising demand for seafood and a levelling of production from capture fisheries, the practice of farming aquatic animals has expanded rapidly to become a major global industry. Aquaculture is now integral to the economies of many countries. It has provided employment and been a major driver of socio-economic development in poor rural and coastal communities, particularly in Asia, and has relieved pressure on the sustainability of the natural harvest from our rivers, lakes and oceans. However, the rapid growth of aquaculture has also been the source of anthropogenic change on a massive scale. Aquatic animals have been displaced from their natural environment, cultured in high density, exposed to environmental stress, provided artificial or unnatural feeds, and a prolific global trade has developed in both live aquatic animals and their products. At the same time, over-exploitation of fisheries and anthropogenic stress on aquatic ecosystems has placed pressure on wild fish populations. Not surprisingly, the consequence has been the emergence and spread of an increasing array of new diseases. This review examines the rise and characteristics of aquaculture, the major viral pathogens of fish and shrimp and their impacts, and the particular characteristics of disease emergence in an aquatic, rather than terrestrial, context. It also considers the potential for future disease emergence in aquatic animals as aquaculture continues to expand and faces the challenges presented by climate change.

Veterinary Research↗
USGS2025

Fisheries dependent and independent data inform a capture technique for an emerging invasive fish species in the mainstem Mississippi River; Black Carp Mylopharyngodon piceus

Black Carp Mylopharyngodon piceus were imported into the United States in the 1970s and 1980s for use in aquaculture; escape occurred and reported wild captures increased. Lacking species-specific capture methods, we assessed fisheries dependent incidental Black Carp catches for a common method, hoop nets, by kernel density analysis to identify an area of increased reporting and compare frequency of reports for water temperature, river stage, and capture date to identify seasonality. We then used fisheries independent effort to identify co-occurrence of species via non-metric multi-dimensional scaling and fit Black Carp catch and environmental covariates by generalized linear models to assess site-specific environmental covariates facilitating capture. The best approximating distribution was refitted for predictions and inference. The greatest density of fisheries dependent hoop net captures (39 %) was near the confluence of the Missouri and Mississippi rivers, primarily from July-September. Captures were characterized by median water temperature 26.7°C, river stage 5.02 m, and 223 day-of-year (DOY; mid-August). Ordination of fisheries independent catch identified similarity in environmental covariates of Smallmouth Buffalo Ictiobus bubalus and Black Carp. The probability of capturing ≥ 1 Black Carp increased with DOY, decreased with increasing current velocity, and increased with depth. Most captures occurred in outside bends (87 %) or side channels (12 %). Probability of Black Carp capture was low but increased in summer and early fall when stage is lower, facilitating reduced current velocity and access to deeper areas. Results may be validated beyond this river segment to test if site-specific hydrology or habitat characteristics facilitated increased commercial and biologist capture and for replication.

Illinois, Missouri↗
USGS2007

The atlantic salmon: Genetics, conservation and management

Atlantic Salmon is a cultural icon throughout its North Atlantic range; it is the focus of probably the World’s highest profile recreational fishery and is the basis for one of the World’s largest aquaculture industries. Despite this, many wild stocks of salmon are in decline and underpinning this is a dearth of information on the nature and extent of population structuring and adaptive population differentiation, and its implications for species conservation. This important new book will go a long way to rectify this situation by providing a thorough review of the genetics of Atlantic salmon. Sponsored by the European Union and the Atlantic Salmon Trust, this book comprises the work of an international team of scientists, carefully integrated and edited to provide a landmark book of vital interest to all those working with Atlantic salmon.

Book↗
USGS2017

Using carbon dioxide in fisheries and aquatic invasive species management

To restore native fish populations, fisheries programs often depend on active removal of aquatic invasive species. Chemical removal can be an effective method of eliminating aquatic invasive species, but chemicals can induce mortality in nontarget organisms and persist in the environment. Carbon dioxide (CO 2 ) is an emerging alternative to traditional chemical control agents because it has been demonstrated to be toxic to fish, but is naturally occurring and readily neutralized. In addition, CO 2 is a commercially available gas, is highly soluble, and has high absorption efficiency. When these characteristics are paired with advances in modern, large-scale gas delivery technologies, opportunities to use CO 2 in natural or artificial (e.g., canals) waters to manage fish become increasingly feasible. Our objective is to describe the history of CO 2 use in fisheries and outline potential future applications of CO 2 to suppress and manipulate aquatic species in field and aquaculture settings.

Fisheries↗
USGS2023

Stocking fish in inland waters: Opportunities and risks for sustainable food systems

Stocking is one of the foremost tools in the inland fisheries management toolbox, but it comes with both opportunities and risks. Stocking is often used as compensation for depleted wild populations, particularly where recruitment processes have been disrupted, but it can introduce disease, disrupt community structures, reduce genetic integrity, and cause conflicts between fishery stakeholders. Despite its widespread use, examples of effective stocking for food fisheries in inland waters are sparse in the peer-reviewed literature. Nevertheless, it is well established that stocking is frequently used to maintain fish yield, so there is a need to conduct the practice in a robust manner that minimises the potential risks. This paper serves as the front matter for a special section of Fisheries Management and Ecology focused on fresh waters feeding the world, which resulted from two panel sessions, one focused on aquaculture and one focused on stocking, hosted by the international InFish research network ( https://infish.org/ ). The paper highlights current practices of fish stock enhancement in inland waters for food, examines potential synergies and interactions of stock enhancement programmes with aquaculture, and provides an outline framework for responsible management of fish stock enhancement.

Fisheries Management and Ecology↗
USGS2024

Assessing habitat use and population dynamics of fisheries resources at Kaloko Fishpond

Throughout Hawai'i, fishponds are considered by their local communities as important cultural touchstones, a source of local, sustainably produced food, and an important component to the development of community-based management for nearshore fisheries. Within Kaloko-Honokōhau National Historical Park, the restoration of Kaloko Fishpond for traditional aquaculture management is a goal of both the National Park Service (NPS) and Hui Kaloko-Honokōhau, a community-based group of kia'i, i.e., caretakers and native Hawaiian cultural practitioners. However, existing data on the demographics and condition of the fish populations within the pond, and the fish-habitat quality are poor to non-existent. Therefore, the objectives of this study were to: catalog fish species composition and distribution in the pond; estimate the abundance of focal species/taxonomic groups; and evaluate the occupancy patterns of the invasive algae Acanthophora spicifera and Upside-down Jellyfish Cassiopea andromeda. As part of these objectives, a survey protocol and analysis framework were designed and evaluated to ensure that the NPS and community group would be able to refine and implement them to continue their monitoring efforts. We conducted dual-observer shore-based visual surveys multiple times per week during September-October 2020 and April-September 2022. A total of 41 species/taxonomic groups were recorded over the course of the surveys. The largest number of species/taxonomic groups were observed at survey stations located on or near the kuapā, or wall separating the fishpond from the ocean. N-mixture models fitted to the data estimated a total population of 353 – 392 mullets, 134 – 192 flagtails (āholehole), and 189 – 277 Milkfish (Awa) Chanos chanos occurring within the 1.2-ha portion of Kaloko Fishpond that could be surveyed visually from the shoreline. Multi-season occupancy models fitted to the surveyed presence of A. spicifera and Upside-down Jellyfish indicted sites throughout most of the pond exhibited moderate and consistent occupancy (ψ = 0.30 – 0.40) throughout much of the pond, except for the northeast corner of the pond (Kaloko Iki) where colonization rates were lower and extinction rates higher than other areas within Kaloko. The visual survey method developed for this study provides a low-cost and effective starting point for the development of methodology that can be used both by NPS personnel and volunteers from the community group. However, we were only able to estimate fish populations for approximately 24% of the area of Kaloko Fishpond with this method. Given that the deeper areas of Kaloko Fishpond are completely inaccessible to the visual survey method used, generating population estimates for the entire pond based on the parameters estimated in the current study is not recommended without further investigation into fish movement and habitat use. Various means to refine this protocol to better meet the needs and abilities of the NPS and community group are proposed.

Hawaii↗
USGS1998

Use of a subsurface plankton layer to benefit a cage-culture fishery in Lake Phewa, Nepal

The Nepalese government and some 225 families in the private sector are engaged in an expanding aquaculture program in lakes Phewa, Begnas and Rupa in the Pokhara Valley, Nepal (Swar & Pradhan 1992). Bighead carp ( Aristichthys nobilis ) and silver carp ( Hypopthalmichthys molitrix ) are propagated in hatchery ponds and are raised to market size in mesh enclosures (having sides, tops and bottoms) suspended to a depth of 2 m. Some 300 cages are presently in use, with annual production varying from 3.4 kg/m 3 Lake Phewa to about 5 kg/m 3 in lakes Begnas and Rupa (Swar & Pradhan 1992). These cage-reared fish are an important source of animal protein and revenue (Swar 1981). Tourism in the region provides growers a continuous market for their fish.

Lake Begnas, Lake Phewa, Lake Rupa↗
USGS2023

Coproduction and modeling spatial contact networks prevent bias about infectious hematopoietic necrosis virus transmission for Snake River Basin salmonids

Much remains unknown about variation in pathogen transmission across the geographic range of a free-ranging fish or animal species and about the influence of movement (associated with husbandry practices or animal behavior) on pathogen transmission. Salmonid hatcheries are an ideal system in which to study these processes. Salmonid hatcheries are managed for endangered species recovery, supplementation of threatened or at-risk fish stocks, support of fisheries, and ecosystem stability. Infectious hematopoietic necrosis virus (IHNV) is a rhabdovirus of significant concern to salmon aquaculture. Landscape IHNV transmission dynamics previously had been estimated only for salmonid hatcheries in the Lower Columbia River Basin (LCRB). The objectives of this study were to estimate IHNV transmission dynamics in a unique geographic region, the Snake River Basin (SRB), and to quantitatively estimate the effect of model coproduction on inference because previous assessments of coproduction have been qualitative. In contrast to the LCRB, the SRB has hatchery complexes consisting of a main hatchery and ≥1 satellite facility. Knowledge about hatchery complexes was held by a subset of project researchers but would not have been available to project modelers without coproduction. Project modelers generated and tested multiple versions of Bayesian susceptible-exposedinfected models to realistically represent the SRB and estimate the effect of coproduction. Models estimated the frequency of transmission routes, route-specific infection probabilities, and infection probabilities for combinations of salmonid hosts and IHNV lineages. Model results indicated that in the SRB, avoiding exposure to IHNV-positive adult salmonids is the most important action to prevent juvenile infections. Migrating adult salmonids exposed juvenile cohort-sites most frequently, and the infection probability was greatest following exposure to migrating adults. Without coproduction, the frequency of exposure by migrating adults would have been overestimated by 70 cohort-sites, and the infection probability following exposure to migrating adults would have been underestimated by∼0.09. The coproduced model had less uncertainty in the infection probability if no transmission route could be identified (Bayesian credible interval (BCI) width = 0.12) compared to the model without coproduction (BCI width = 0.34). Evidence for virus lineage MD specialization on steelhead and rainbow trout (both Oncorhynchus mykiss) was apparent without model coproduction. In the SRB, we found a greater probability of virus lineage UC infection in Chinook salmon (Oncorhynchus tshawytscha) compared to in O. mykiss, whereas in the LCRB, UC more clearly exhibited a generalist approach. Coproduction influenced estimates that depended on transmission routes, which operated differently at main hatcheries and satellite sites within hatchery complexes. Hatchery complexes are found outside of the SRB and are not specific to salmonid hatcheries alone. There is great potential for coproduction and modeling spatial contact networks to advance understanding about infectious disease transmission in complex production systems and surrounding free-ranging animal populations.

Idaho, Oregon, Washington↗
USGS1998

Vertical distribution of the chloromonad flagellate Heterosigma carterae in columns: Implications for bloom development

Blooms of the marine flagellate Heterosigma carterae have been associated with catastrophic fish kills at mariculture facilities around the world. The precise cause(s) of the sudden appearance and disappearance of Heterosigma surface blooms has not been completely described or understood. Environmental data from prior studies of blooms indicate the presence of vertical stratification of the water column that is often induced by freshwater runoff. We report the relatively rapid concentration of Heterosigma cells at the surface of tubes shortly after the addition of distilled water to the surface. This phenomenon of cell concentration in surface waters may partially explain the sudden appearance of Heterosigma cells near the surface and subsequent disappearance when vertical stratification is lost due to turbulence or mixing. The results may lead to bloom mitigation techniques for net pen aquaculture.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2005

Use of prepositioned grid electrofishers for the collection of robust redhorse broodstock

We investigated the potential of prepositioned grid electrofishers as a means of collecting broodstock for the rare robust redhorse Moxostoma robustum. We found that combined with visual observation, this technique allowed for the efficient capture of fish in breeding condition. We were able to harvest eggs in the field and bring only fertilized eggs into the hatchery. There was no need to induce spawning hormonally. Although their use is limited by water depth and clarity, prepositioned grid electrofishers used in conjunction with visual observation warrants further consideration as an effective tool for the collection of reproductively active broodstock for conservation purposes. ?? Copyright by the American Fisheries Society 2005.

North American Journal of Aquaculture↗
USGS2012

Assessing consumption of bioactive micro-particles by filter-feeding Asian carp

Silver carp Hypophthalmichthys molitrix (SVC) and bighead carp H. nobilis (BHC) have impacted waters in the US since their escape. Current chemical controls for aquatic nuisance species are non-selective. Development of a bioactive micro-particle that exploits filter-feeding habits of SVC or BHC could result in a new control tool. It is not fully understood if SVC or BHC will consume bioactive micro-particles. Two discrete trials were performed to: 1) evaluate if SVC and BHC consume the candidate micro-particle formulation; 2) determine what size they consume; 3) establish methods to evaluate consumption of filter-feeders for future experiments. Both SVC and BHC were exposed to small (50-100 μm) and large (150-200 μm) micro-particles in two 24-h trials. Particles in water were counted electronically and manually (microscopy). Particles on gill rakers were counted manually and intestinal tracts inspected for the presence of micro-particles. In Trial 1, both manual and electronic count data confirmed reductions of both size particles; SVC appeared to remove more small particles than large; more BHC consumed particles; SVC had fewer overall particles in their gill rakers than BHC. In Trial 2, electronic counts confirmed reductions of both size particles; both SVC and BHC consumed particles, yet more SVC consumed micro-particles compared to BHC. Of the fish that ate micro-particles, SVC consumed more than BHC. It is recommended to use multiple metrics to assess consumption of candidate micro-particles by filter-feeders when attempting to distinguish differential particle consumption. This study has implications for developing micro-particles for species-specific delivery of bioactive controls to help fisheries, provides some methods for further experiments with bioactive micro-particles, and may also have applications in aquaculture.

Journal of Aquaculture Research & Development↗
USGS2003

Comparative hydraulics of two fishery research circular tanks and recommendations for control of experimental bias

Hydraulic characteristics inside two research circular tanks (1.5-m and 1.2-m diameter) with the same volume of water were studied to understand how they might affect experimental bias by influencing the behavior and development of juvenile fish. Water velocities inside each tank were documented extensively and flow behavior studied. Surface inflow to the 1.5-m tank created a highly turbulent and aerated surface, and produced unevenly distributed velocities within the tank. A low-flow velocity, or "dead" zone, persisted just upstream of the surface inflow. A single submerged nozzle in the 1.2-m tank created uniform flow and did not cause undue turbulence or introduce air. Flow behavior in the 1.5-m tank is believed to have negatively affected the feeding behavior and physiological development of a group of juvenile fall chinook salmon, Oncorhynchus tshawytscha. A new inflow nozzle design provided comparable flow behavior regardless of tank size and water depth. Maintaining similar hydraulic conditions inside tanks used for various biological purposes, including fish research, would minimize experimental bias caused by differences in flow behavior. Other sources of experimental bias are discussed and recommendations given for reporting and control of experimental conditions in fishery research tank experiments.

Journal of Applied Aquaculture↗
USGS2017

In memoriam - William Toshio (Tosh) Yasutake, 1922-2016

William Toshio (Tosh) Yasutake, 1922-2016 passed away peacefully at home on December 12, 2016, at the age of 94. He is survived by Fumi, his wife of 66 years, as well as four children and six grandchildren. With his death, the fish health community has lost an outstanding scientist as well as a kind, unassuming, and wonderful human being. Tosh was born on June 10, 1922, in Seattle, Washington, to Jack and Hide Yasutake. He was in his first year of studies at the University of Washington when Pearl Harbor was attacked by Imperial Japan on December 7, 1941. Following the attack, Tosh and his family (father, mother, sister, and two brothers) were among the 110,000–120,000 people of Japanese ancestry who were forced from their homes on the Pacific coast and incarcerated in internment camps in the interior. In June 1942, Tosh enlisted in the U.S. Army, serving as an unarmed combat medic in the famed 442nd Regimental Combat Team, the most decorated unit for its size and length of service in the history of American warfare. Wounded in October 1944 during the Vosges Mountains campaign near Bruyères, France, Tosh was evacuated and missed the ensuing battle to rescue the “Lost Battalion,” at which his replacement was killed. Tosh returned to action in Italy in February 1945 and served until the end of the war in Europe, earning both a Purple Heart and a Bronze Star for bravery. In October 2010, the Congressional Gold Medal was awarded to the 442nd Regimental Combat Team, and in 2012 the surviving members were made chevaliers of the French Légion d’Honneur for actions contributing to the liberation of France in World War II. After the war, Tosh returned to the University of Washington on the GI Bill and received a B.S. degree in zoology in 1951. In 1953 he began his research career at the U.S. Fish and Wildlife Service’s Western Fish Nutrition Laboratory at Cook, Washington, where he conducted pioneering research on nutritional fish diseases with John Halver. Tosh was one of the first to recognize hepatomas in hatchery-reared Rainbow Trout and helped to trace the disease to an aflatoxin produced by the mold Aspergillus flavis , which grew during the storage of ingredients for fish diets. In 1960, he transferred to the Western Fisheries Research Center (WFRC) in Seattle (then called the Western Fish Disease Laboratory) to start a fish pathology diagnostic laboratory. There he described the histopathology of diseases of economically important fishes, identified etiologic agents, and worked with hatchery biologists to improve the health, quality, and survival of salmonids released from federal and state hatcheries. Tosh was instrumental in recognizing that the viruses of Oregon sockeye disease and Chinook Salmon virus disease were one entity and in giving the disease its present name: infectious hematopoietic necrosis. In recognition of his pioneering research, Tosh was awarded a doctorate in fish pathology by the University of Tokyo in 1980, the first American to have been so honored. In 1983, he published his classic textbook The Microscopic Anatomy of Salmonids: An Atlas , which quickly became a standard reference work in fish pathology and is still in wide use today. For his outstanding career achievements, in 1987 Tosh received the S. F. Snieszko Distinguished Service Award, the highest honor bestowed by the American Fisheries Society’s Fish Health Section (AFS–FHS). Tosh retired in 1988 but continued his research at the WFRC as a senior scientist emeritus, providing technical assistance to federal and state agencies and to the aquaculture industry worldwide. His culminating project was to digitize his lifetime collection of photomicrographs and prepare an atlas, “Histopathology of Selected Parasitic Salmonid Diseases: A Color Atlas,” that is now posted on the Web sites of the WFRC and the AFS–FHS. Although his presence will be sorely missed, his research contributions have become part of the foundation of today’s knowledge of fisheries biology and have assured him a place in history.

Journal of Aquatic Animal Health↗
USGS2005

Examining Neosho madtom reproductive biology using ultrasound and artificial photothermal cycles

We examined whether extended laboratory simulation of natural photothermal conditions could stimulate reproduction in the Neosho madtom Noturus placidus, a federally threatened species. For 3 years, a captive population of Neosho madtoms was maintained under simulated natural conditions and monitored routinely with ultrasound for reproductive condition. Female Neosho madtoms cycled in and out of spawning condition, producing and absorbing oocytes annually. Internal measurements made by means of ultrasound indicated the summer mean oocyte size remained consistent over the years, although estimated fecundity increased with increasing fish length. In the summer of 2001, after 3 years in the simulated natural environment, 13 out of 41 fish participated in 10 spawnings. Simulation of the natural photothermal environment, coupled with within-day temperature fluctuations during the spring rise, seemed important for the spawning of captive Neosho madtoms. The use of ultrasound to assess the reproductive status in Neosho madtoms was effective and resulted in negligible stress or injury to the fish. These procedures may facilitate future culture of this species and other madtoms Noturus spp., especially when species are rare, threatened, or endangered. ?? Copyright by the American Fisheries Society 2005.

North American Journal of Aquaculture↗
USGS2005

Efficacy of hydrogen peroxide versus formalin treatments to control mortality associated with saprolegniasis on lake trout eggs

We compared the efficacy of hydrogen peroxide versus formalin treatments to control fungal infections on eggs of lake trout Salvelinus namaycush incubated at a hatchery in Wisconsin. Four strains of lake trout eggs were incubated in six vertical-flow Heath incubators; three replicate incubators for each chemical. Each incubator had 13 trays containing approximately 25,000-30,000 eggs/tray. Formalin (1,667 mg/L) or hydrogen peroxide (1,000 mg/L) treatments were administered once daily for 15 min up to the development of visible eye spots in the eggs (eyed egg stage). Eyed and dead eggs were separated using a photoelectric egg sorter, and the number of live and dead eggs was determined volumetrically. In the hydrogen peroxide test group, the bottom trays of each incubator had fungus present on the eggs, whereas no fungus was observed on eggs treated with formalin. The mean percentage of eyed eggs for an incubator treated with formalin (75%) was significantly greater than an incubator treated with hydrogen peroxide (70%). Formalin was the most efficacious therapeutant; however, both therapeutants were effective in increasing lake trout egg survival up to the eyed egg stage. ?? Copyright by the American Fisheries Society 2005.

North American Journal of Aquaculture↗