USGS Science⌕ Search

SEARCH · USGS Science

Results for “Fisheries Research”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources
USGS1973

Age, growth, spawning season, and fecundity of the trout-perch (Percopsis omiscomaycus) in southeastern Lake Michigan

Growth of trout-perch ( Percopsis omiscomaycus ) in the first 2 years of life was somewhat slower in southeastern Lake Michigan (average length at end of second year, 83 mm) than in Lower Red Lake, Minnesota (90 mm), but considerably faster than in Lake Superior (58 mm); size differences in later years were slightly less pronounced. Young fish began growing earlier in the year (some before June 20) than older ones (as late as August). Females tended to live longer than males, as they do in Lower Red Lake and Lake Superior. Trout-perch spawned from late June or early July until late September, somewhat later than in Lower Red Lake (May to August) or Lake Erie (June to August). Fecundity was similar to that in Lake Erie; mature females 94-146 mm long contained from 126 to 1329 yolked eggs.

Journal of the Fisheries Research Board of Canada↗
USGS1973

Computer program for sample sizes required to determine disease incidence in fish populations

A computer program is described for generating the sample size tables required in fish hatchery disease inspection and certification. The program was designed to aid in detection of infectious pancreatic necrosis (IPN) in salmonids, but it is applicable to any fish disease inspection when the sampling plan follows the hypergeometric distribution.

Journal of the Fisheries Research Board of Canada↗
USGS1973

Fish viruses: Isolation and identification of infectious hematopoietic necrosis in eastern North America

Infectious hematopoietic necrosis virus (IHNV) was isolated from diseased fingerling rainbow trout ( Salmo gairdneri ) from a hatchery in West Virginia. Clinical signs, histopathologic findings, and origin of eggs provided a basis for diagnosis, and virus was isolated and presumptively identified by plaque characteristics. Serum neutralization tests provided positive identification of the agent as IHNV, and electronmicroscopy showed its rhabdovirus morphology. Experimental infections resulted in signs of IHNV and death; test fish had characteristic histopathologic alterations and appropriate virus titers. This is the first completely documented occurrence of IHNV beyond the Pacific Northwest.

Journal of the Fisheries Research Board of Canada↗
USGS1973

Endrin uptake and release by fingerling channel catfish (Ictalurus punctatus)

Fingerling channel catfish ( Ictalurus punctatus ) offered diets containing 0.04–4.0 μg endrin/g food (dry weight) rapidly accumulated the pesticide. Amounts in the tissues were directly proportional to amounts in the food. Dietary endrin had no measurable effect on growth or mortality. After endrin was withdrawn from the diet, it rapidly disappeared and could not be detected after 41 days. In fish exposed to 0.5 μg endrin/liter of water, mortalities began at tissue levels of 0.7 μg endrin/g of wet whole fish and total mortality occurred at levels near 1.0 μg/g.

Journal of the Fisheries Research Board of Canada↗
USGS1973

Open-jaw syndrome in chinook salmon ( Oncorhynchus tshawytscha ) at a hatchery

Nearly 0.5% of the yearling spring chinook salmon ( Oncorhynchus tshawytscha ) at a national fish hatchery were observed with mouth agape, the condition occurring in two of 16 ponds. X-radiographs and histological preparations indicated that the articular bone of the lower jaw was malformed and dislocated dorsal and posterior to its normal point of attachment. The bone appeared to be embedded in the mandibular muscle and surrounded by an extensive fibrous tissue network. Genetic aberration, environmental interaction, and teratogenic substances are discussed as possible causes of the anomaly.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Myxosoma cerebralis: Isolation and concentration from fish skeletal elements - Sequential enzymatic digestions and purification by differential centrifugation

An effective sequential procedure for recovery of Myxosoma cerebralis spores from infected trout was developed, and quantification of spores was carried out at each step of release and concentration. Methods are described for fresh and frozen material. Effective concentration of from 1100- to 9000-fold and an estimated efficiency of recovery of about 80% has been achieved. Tabular and graphic data are presented with recommendations for diagnostic applications. The immediate applications of these procedures are in implementing more effective detection and in preparing antigen for the immunologic studies that should provide the most sensitive detection.

Journal of the Fisheries Research Board of Canada↗
USGS1974

In vitro and in vivo efficacy of potentiated sulfonamide in control of furunculosis in salmonids

In vitro and in vivo efficacy of a potentiated sulffonamide, Ro5–0037, for inhibition of Aeromonas salmonicida , causative agent of fish furunculosis was determined. The components of the potentiated sulfonamide, sulfadimethoxine, and ormetoprim were tested alone and in combination. In vitro results showed that both sulfonamide-resistant and sensitive strains of A . salmonicida had greater sensitivity to Ro5–0037 than to either of its components. Also, sulfonamide-sensitive strains developed resistance to ormetoprim and sulfadimethoxine more rapidly than to Ro5–0037. Efficacy studies with small numbers of artificially infected trout revealed that Ro5–0037 effectively controlled furunculosis at 50 mg/kg of fish/day, one fourth the usual sulfonamide dosage level. Extensive field trials also showed the 50 mg/kg level of Ro5–0037 gave effective control of hatchery outbreaks of furunculosis. As found in the in vitro studies, all in vivo trials indicated the combination of ormetoprim and sulfadimethoxine was more efficient in inhibiting A . salmonicida than either component alone.

Journal of the Fisheries Research Board of Canada↗
USGS1973

Stress of formalin treatment in juvenile spring chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Salmo gairdneri>)

The physiological stress of 200 ppm formalin treatments at 10 C is more severe in the juvenile steelhead trout ( Salmo gairdneri ) than in the spring chinook salmon ( Oncorhynchus tshawytscha ). In the steelhead, a marked hypochloremia follows a 1-hr treatment and recovery requires about 24 hr. During longer treatments, hypercholesterolemia together with reduced regulatory precision, hypercortisolemia, alkaline reserve depletion, and hypocapnia unaccompanied by a fall in blood p H occur — suggestive of compensated respiratory alkalosis. In the spring chinook, hypochloremia and reduced plasma cholesterol regulatory precision are the significant treatment side effects but recovery requires only a few hours. Formalin treatments also cause epithelial separation, hypertrophy, and necrosis in the gills of both fishes but again, consistent with the physiological dysfunctions, these are more severe in the steelhead.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Residues of DDT in lake trout (Salvelinus namaycush) and coho salmon (Oncorhynchus kisutch) from the Great Lakes

Concentrations of DDT residues were higher in lake trout ( Salvelinus namaycush ) from southern Lake Michigan in 1966–70 (average 18.1 ppm in fish 558–684 mm long) than in lake trout of the same size-class from Lake Superior in 1968–69 (4.4 ppm), and higher in adult coho salmon ( Oncorhynchus kisutch ) from Lake Michigan in 1968–71 (averages for different year-classes, 9.9–14.0 ppm) than in those from Lake Erie in 1969 (2.2 ppm). Residues were significantly higher in lake trout from southern Lake Michigan than in those from the northern part of the lake. In lakes Michigan and Superior, the levels increased with length of fish and percentage oil. In Lake Michigan coho salmon, the residues remained nearly stable (2–4 ppm) from September of the 1st yr of lake residence through May or early June of the 2nd yr, but increased three to four times in the next 3 mo. Residues in Lake Erie coho salmon did not increase during this period, which preceded the spawning season. Although the concentrations of total residues in whole, maturing Lake Michigan coho salmon remained unchanged from August 1968 until near the end of the spawning season in January 1969, the residues were redistributed in the tissues of the spawning-run fish; concentrations in the loin and brain were markedly higher in January than in August. This relocation of DDT residues accompanied a marked decrease in the percentage of oil in the fish, from 13.2 in August to 2.8 in January. Concentrations of residues were relatively high in eggs of both lake trout (4.6 ppm) and coho salmon (7.4–10.2 ppm) from Lake Michigan. The percentage composition of the residues ( p , p ′DDE, o , p ′/DDT, p , p ′DDT, and p , p ′DDT) did not differ significantly with life stage, size, age, or locality, or date of collection of lake trout or coho salmon.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Comparison of protection in rainbow trout (Salmo gairdneri) inoculated with and fed Hagerman redmouth bacterins

Rainbow trout ( Salmo gairdneri ) fed 1.0 mg Hagerman redmouth bacterin per fish for 2 wk had no detectable specific, circulating, agglutinating antibody. In fish given a single subcutaneous inoculation of 1.0 mg of bacterin per fish, antibody was present from 3 wk later until 3 mo later, when the final sample was taken. Median lethal doses at various intervals after the bacterins were administered indicated that the inoculated fish could withstand a greater challenge by subcutaneous inoculation of the virulent bacteria than the orally immunized fish. The fish fed the vaccine lost their protection within 6 wk, whereas the inoculated fish had high levels of protection through 3 mo. The degree of protection was also confirmed by a "natural" exposure challenge.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Pathophysiology of infectious hematopoietic necrosis virus disease in rainbow trout (Salmo gairdneri): early changes in blood and aspects of the immune Response after Injection of IHN Virus

Juvenile rainbow trout ( Salmo gairdneri ) were injected with infectious hematopoietic necrosis (IHN) virus and various hematological and blood chemical changes were monitored over 9 days. The packed cell volume, hemoglobin, red blood cell count, and plasma bicarbonate were significantly depressed by day 4. Plasma chloride, calcium, phosphorus, total protein, and blood cell types did not change during the 9 days. Furthermore, plasma LDH isozyme was significantly increased by the fourth day, and fish infected with infectious pancreatic necrosis virus, Vibrio anguillarum , Aeromonas salmonicida , and redmouth bacterium did not show specific LDH isozyme alterations. Acid-base alterations occurred at 10 C but not at 18 C. The acid-base imbalance and elevation of the LDH isozyme were consistently associated with the early development of the disease.The immune response after injection of IHN virus was determined and protection from disease was tested by passive immunization. Actively immunized fish developed IHN-neutralizing antibodies within 54 days after injection of virus, and the antibodies were protective when juvenile fish were passively immunized and experimentally challenged with IHN virus.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Fish sporozoa: Extraction of antigens from Myxosoma cerebralis spores which mimic tissue antigens of rainbow trout (Salmo gairdneri)

This is the first report of an antigenic preparation from the spore stage of any histozoic sporozoan parasite. The method for successful extraction of the antigens is presented. This antigenic preparation is active in rabbits, but not salmonid fish. The detection of asymptomatic carrier fish using the spore antigens was not successful and evidence is presented to show that the parasite is successful because its antigens mimic those of trout. Immunoelectrophoresis indicates the parasite and trout antigens are different proteins.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Effect of acclimation temperature and heat shock on vulnerability of fry of lake whitefish ( Coregonus clupeaformis ) to predation

Fry of lake whitefish ( Coregonus clupeaformis ) acclimated to 10, 15, and 18 C were exposed to temperatures of 24.5, 25, and 28 C for 1 min and then immediately returned to water at their acclimation temperature, in test tanks containing yearling yellow perch ( Perca flavescens ). The number of attacks on the fry and the number captured and eaten in 30 min were recorded in separate tests of shocked and unshocked (control) whitefish.Significantly more whitefish were captured per attack (data for shocked and unshocked fry combined) at 15 and 18 C than at 10 C; and shocked fry were significantly more vulnerable to capture by the perch than were unshocked controls.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Myxosoma cerebralis: Comparative sensitivity of spore detection methods

Physical and biophysical methods of detecting spores of Myxosoma cerebralis were used in sequence on 87 individual fingerling rainbow trout ( Salmo gairdneri ) from two populations with a low incidence of infection. Physical methods of releasing spores from the organs of equilibrium, gill arches, or the axial skeleton gave an estimated rate of infection of 2.3–4.6%. Each succeeding step — pepsin digestion, trypsin digestion, and differential centrifugation through 55% dextrose solution — revealed additional infected fish. The final step of the sequence detected 10.5 times more infected fish than were found by examination of the organs of equilibrium or the axial skeleton with physical means; the true incidence was at least 24.1%. Procedures are described for using biophysical methods on 60-fish pools for hatchery inspection work and also on the more bony skeletons of mature fish.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Effect of temperature on accumulation of methylmercuric chloride and p,p'DDT by rainbow trout (Salmo gairdneri)

Amounts of mercury and DDT residues accumulated from water by yearling rainbow trout ( Salmo gairdneri ) in the laboratory increased as water temperature increased. Fish exposed to methylmercuric chloride at concentrations of 234&ndash;263 parts per trillion for 12&ensp;wk at 5, 10, and 15&ensp;C accumulated 1.19, 1.71, and 1.96&ensp;ppm; fish exposed to p , p &prime;DDT at concentrations of 133&ndash;176 parts per trillion accumulated 3.76, 5.93, and 6.82&ensp;ppm. Concentrations of mercury accumulated by the fish were significantly different ( P &ensp;<&ensp;0.01) at each of the three temperatures, and the concentrations of DDT were significantly different at 5 and 10 and 5 and 15&ensp;C. Throughout the period of exposure, the concentration factors (concentration of contaminant in the fish/concentration in water) at each of the three temperatures were far higher for p , p &prime;DDT than for methylmercuric chloride.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Effect of feeding brown trout (Salmo trutta) a diet pelleted in dry and moist forms

Growth rate, body composition, and intake of either dry matter or energy did not differ significantly ( P > 0.05) between two groups of juvenile brown trout ( Salmo trutta ) fed either a low- or high-moisture semipurified diet at different rates to compensate for a diet energy density gradient. Feed/gain efficiency, on an as-fed basis, was significantly greater ( P < 0.01) in fish fed the low-moisture diet, but did not differ ( P > 0.05) when compared on the basis of dry matter or energy intake.

Journal of the Fisheries Research Board of Canada↗