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PubMedDate not supplied

Fish consumption advisories and outreach programs for Southeast Asian immigrants.

Southeast Asian immigrants and refugees, in particular the Hmong people of Laos, have settled in large numbers in metropolitan areas of Minnesota. These communities, accustomed to hunting and fishing for food in Laos, now fish in some of the most contaminated waters of Minnesota. Fishing and fish-preparation customs of their homeland emphasize using all fish caught and discarding very little waste. These practices result in a potentially high exposure to PCBs and mercury. Educational outreach efforts to inform this population of the potential health hazards from consuming the fish are hindered by language and cultural barriers. While most Hmong anglers welcome information about contaminants and fishing, the typical press releases and mailings that convey fish advisory information to the public do not reach this community. The Minnesota Department of Health and the Minnesota Department of Natural Resources collaborated to determine the health messages and communication methods that would best meet the needs of these communities. Using the results of interviews and a behavioral survey, the Minnesota Department of Health has tailored fish consumption advisories to meet the unique needs of Southeast Asian anglers. Over the past four years, educational programs involving specialized advisories, translations, signs, a Hmong language video, and workshops have been used to inform Hmong anglers and other Southeast Asians about fish contaminants.

Asia, Southeastern↗
PubMed2004

Larvae of gryporhynchid cestodes (Cyclophyllidea) from fish: a review.

Larvae (metacestodes) of tapeworms of the cyclophyllidean family Gryporhynchidae (previously included in the Dilepididae) occur in different internal organs of fresh- and brackish water fish (110 fish species of 27 families in 12 orders reported), which serve as the second intermediate hosts. The species composition, spectrum of fish hosts, sites of infection, and geographical distribution of gryporhynchids recorded from fish are reviewed here on the basis of literary data and examination of extensive material from helminthological collections. Metacestodes of the following genera have been found in fish: Amirthalingamia Bray, 1974 (1 species), Ascodilepis Guildal, 1960 (1), Cyclustera Fuhrmann, 1901 (4), Dendrouterina Fuhrmann, 1912 (1), Glossocercus Chandler, 1935 (3), Neogryporhynchus Baer et Bona, 1960 (1), Paradilepis Hsü, 1935 (5), Parvitaenia Burt, 1940 (2), and Valipora Linton, 1927 (3). However, most published records concern only three species, namely Neogryporhynchus cheilancristrotus (Wedl, 1855) from the intestinal lumen, Paradilepis scolecina (Rudolphi, 1819) from the liver and mesenteries, and Valipora campylancristrota (Wedl, 1855) from the gall bladder of cyprinids and other fish in the Palaearctic Region. Data on other species as well as reports from other regions are very scarce and almost no information is available from Australia, tropical Asia and South America. A recent study of gryporhynchid metacestodes from Mexico (Scholz and Salgado-Maldonado 2001), which reported 13 species, suggested that they may be more common than indicated by records in the literature. Although only a few cases of pathogenic influence of larvae on fish hosts have been reported, the veterinary importance of gryporhynchids remains to be assessed on the basis of more detailed studies. The data available indicate a strict host and site specificity of some species whereas others occur in a wide spectrum of fish hosts and are not strictly site-specific. Evaluation of Paradilepis larvae from the liver of salmonid fish from British Columbia, Canada, identified as P. simoni Rausch, 1949 by Ching (1982), has shown that they probably belong to two species, P. simoni and P. rugovaginosus Freeman, 1954. Metacestodes of the latter species and those of Cyclustera magna (Baer, 1959) from the intestinal wall of Tilapia zillii (Gervais) from Kenya are reported from fish for the first time.

Animals↗
PubMed2006

Alternative approaches can greatly reduce the number of fish used for acute toxicity testing.

Acute toxicity tests with algae, daphnids, and fish are required for the classification and environmental risk assessment of chemicals. The degree of risk is determined by the lowest of these acute toxicity values. Many ecotoxicological programs are seeking to reduce the numbers of fish used in acute toxicity testing. The acute threshold test is a recently proposed strategy that uses, on average, only 10 (instead of 54) fish per chemical. We examined the consequences of reducing the number of fish used in toxicity testing on the ultimate outcome of risk assessments. We evaluated toxicity data sets for 507 compounds, including agrochemicals, industrial chemicals, and pharmaceuticals from our internal database. Theoretical applications of the acute threshold test gave similar results to those obtained with the standard fish median lethal concentration (LC50) test but required only 12% as many fish (3195 instead of 27,324 fish used for all compounds in the database). In 188 (90%) of the 208 cases for which a complete data set was available, the median effect concentration for algae or daphnids was lower than the LC50 for fish. These results show that replacement of the standard fish LC50 test by the acute threshold test would greatly reduce the number of fish needed for acute ecotoxicity testing without any loss of reliability.

Animals↗
PubMed2001

Combined effects of predatory fish and sublethal pesticide contamination on the behavior and mortality of mayfly nymphs.

We evaluated the potential interaction of pesticide effect and predatory fish on behavior and mortality of a stream mayfly. Experiments in laboratory stream microcosms compared the activity, drift, and mortality of Baetis mayfly nymphs in the absence of fish with that in the presence of Cape galaxias (Galaxias zebratus), both species inhabiting the same stream environments in the Western Cape of South Africa. These two predator treatments were combined with exposure either to no pesticide or to 0.2 microg/L of the organophosphate insecticide azinphos-methyl (AZP) or 0.2 microg/L of the pyrethroid insecticide fenvalerate (FV). Such pesticide levels are known from transient spraydrift- or runoff-related pesticide input into running waters. Each of the six combinations was replicated six times as 30-min trials during the day and effects were analyzed using 2 x 2 factorial analysis of variance (ANOVA). A single exposure to either fish or pesticide significantly increased the absolute activity of mayflies, measured as number of animals visible on top of stones, and the absolute mayfly drift in the fish treatment and in the FV treatment but did not increase the mortality above 0.8%. The combination of predator presence and sublethal pesticide exposure resulted in a significant increase in the mortality rate, to about 9% in the AZP x fish and 25% in the FV x fish treatment, although the activity and drift rates were not increased compared with the single-stressor treatments. Two-by-two factorial ANOVA and the comparison of expected and measured responses indicated that the mortality resulted from a synergistic interaction of the two stressors. The observed mortality was without exception caused by predation of the fish on drifting mayflies. The relative drift rate in the FV x fish treatment was decreased, again due to a synergistic interaction, which suggests an active drift avoidance reaction of the mayflies exposed to the combined pesticide x fish treatment, in contrast with those exposed just to FV. We conclude that the drift response of mayflies to transient sublethal pesticide exposure results in a synergistically increased adverse effect in the presence of predatory fish.

Animals↗
PubMed2001

Higher intakes of fish protein are related to a lower risk of microalbuminuria in young Swedish type 1 diabetic patients.

OBJECTIVE: To examine the influence of dietary intake from various protein and fat sources on the occurrence of microalbuminuria in type 1 diabetic patients. RESEARCH DESIGN AND METHODS: In this nested case control study, 1,150 patients with diabetes duration >5 years reported dietary habits for the previous 12 months and submitted urinary samples for the analysis of albumin excretion rate (AER). A total of 75 cases of albuminuria (overnight AER > or = 15 microg/min) were identified and compared with 225 duration-matched control subjects. RESULTS: Neither mean protein, fat intake, average fish protein intake (control subjects 4.56 +/- 3.83 g/day and cases 3.82 +/- 2.87 g/day; P = 0.12), nor intake of meat and vegetable protein differed between the cases of albuminuria and the control subjects. High consumers of fish protein (greater than the 75th percentile) (12 cases and 63 control subjects, mean intake 9.35 g fish protein/day, i.e., approximately 53 g fish/day) had lower odds ratios (ORs) for microalbuminuria than individuals consuming less fish protein (mean 2.72 g/day) (crude OR 0.49 and 95% CI 0.25-0.97). When adjusted for known confounding factors, such as HbA1c, mean arterial pressure, diabetes duration, age, sex, smoking, BMI, country region, and total energy, individuals with a high intake of fish protein and fish fat showed a reduction in the risk for microalbuminuria (OR 0.22 and 0.31, respectively; 95% CI 0.09-0.56 and 0.13-0.76, respectively). When fish protein and fat were adjusted for each other, a high intake of fish protein but not of fish fat was still significantly associated with a decrease in the risk for microalbuminuria. CONCLUSIONS: Total protein and fat intake were not associated with the presence of microalbuminuria, but a diet including a high amount of fish protein seemed to lessen the risk.

Albuminuria↗
PubMedDate not supplied

Allergic reactions following skin contact with fish.

We evaluated the clinical characteristics found in 29 children who showed allergic symptoms after direct and/or indirect contact with fish, from 197 children diagnosed with IgE-mediated fish hypersensitivity. Allergic reactions to fish through ingestion began in most patients (79%) within the first 24 months of life. All the patients showed cutaneous symptoms, either alone or associated with other clinical manifestations. Whiff and hake were the species more frequently implicated in eliciting clinical manifestations upon ingestion. After diagnosis, all patients were placed on a strict fish avoidance diet. During this period of avoidance, 29 patients reported allergic reactions (mean age 5 years, 6 months; SD 4 years, 2 months) after incidental skin contact with fish. Clinical manifestations after touching fish were only cutaneous in 28 of the 29 studied patients. One showed local urticaria with wheezing. The majority reported two or more episodes. Incidental skin contact with fish could play an important role in accidental encounters with fish particles in children on a fish avoidance diet for fish IgE-mediated hypersensitivity. Such exposures could result in immunologic immediate contact reactions and in some cases could lead to systemic reactions (contact urticaria syndrome).

Animals↗
PubMed2000

Influence of dietary fish oil on conjugated linoleic acid and other fatty acids in milk fat from lactating dairy cows.

Lactating cows were fed menhaden fish oil to elevate concentrations of conjugated linoleic acid, transvaccenic acid, and n-3 fatty acids in milk. Twelve multiparous Holstein cows at 48+/-11 DIM were assigned randomly to a replicated 4 x 4 Latin square. Each treatment period was 35 d in length, with data collected d 15 to 35 of each period. On a dry matter (DM) basis, diets contained 25% corn silage, 25% alfalfa hay, and 50% of the respective concentrate mix. Fish oil was supplemented at 0, 1, 2, and 3% of ration DM. Linear decreases were observed for DM intake (28.8, 28.5, 23.4, and 20.4 kg/d) and milk fat (2.99, 2.79, 2.37, and 2.30%) for 0 to 3% dietary fish oil, respectively. Milk yield (31.7, 34.2, 32.3, and 27.4 kg/d) increased as dietary fish oil increased from 0 to 1% but decreased linearly from 1 to 3% dietary fish oil. Milk protein percentages (3.17, 3.19, 3.21, and 3.17) were similar for all treatments. When the 2% fish oil diet was fed, concentrations of conjugated linoleic acid and transvaccenic acid in milk fat increased to 356% (to 2.2 g/ 100 g of total fatty acids) and 502% (to 6.1 g/100 g), respectively, of amounts when 0% fish oil was fed. There were no additional increases in these fatty acids when cows were fed 3% fish oil. The n-3 fatty acids increased from a trace to over 1 g/100 g of milk fatty acids, when the 3% fish oil diet was fed. Fish oil supplementation to diets of dairy cows increased the conjugated linoleic acid, transvaccenic acid, and n-3 fatty acids in milk.

Animal Feed↗
PubMed2001

Composition and properties of milk and butter from cows fed fish oil.

A control diet and a fish oil diet were fed to 12 multiparous Holstein cows to determine how the incorporation of Menhaden fish oil in the diet would influence the fatty acid composition, especially the conjugated linoleic acid and transvaccenic acid, contents of milk and butter. The control diet consisted of a 50:50 ratio of forage to concentrate, and the fish oil diet consisted of the control diet with 2% (on a dry matter basis) added fish oil. Milk from cows fed the control diet contained higher average concentrations of milk fat (3.37%) compared with milk from cows fed the fish oil diet (2.29%). Milk from cows fed fish oil contained higher concentrations of conjugated linoleic acid, transvaccenic acid, and total unsaturated fatty acids (0.68 and 2.51; 1.42 and 6.28; and 30.47 and 41.71 g/100 g of fat, respectively). Butter made from the fish oil diet milk also had higher concentrations of conjugated linoleic acid, transvaccenic acid, and unsaturated fatty acids. Penetrometer readings indicated fish oil diet butters were softer at 4 and 20 degrees C than the control diet butters. Acid degree values were similar in the fish oil butters compared with the control butters. No significant difference was found in the flavor characteristics of milk and butter from cows fed the control and fish oil diets. Production of milk and butter with increased amounts of conjugated linoleic acid, transvaccenic acid, and other beneficial fatty acids may have a desirable impact on the health of consumers and lead to increased sales.

Animals↗
PubMed2001

Composition and flavor of milk and butter from cows fed fish oil, extruded soybeans, or their combination.

Milk was collected from eight multiparous Holstein and four multiparous Brown Swiss cows that were distributed into four groups and arranged in a randomized complete block design with four 4-wk periods. The four treatments included a control diet of a 50:50 ratio of forage-to-concentrate; a fish oil diet of the control diet with 2% (on dry matter basis) added fat from menhaden fish oil; a fish oil with extruded soybean diet of the control diet with 1% (on dry matter basis) added fat from menhaden fish oil and 1% (on dry matter basis) added fat from extruded soybeans; and an extruded soybean diet of the control diet with 2% (on dry matter basis) added fat from extruded soybeans. Milk from cows fed control, fish oil, fish oil with extruded soybean, and extruded soybean diets contained 3.31, 2.58, 2.94, and 3.47% fat, respectively. Concentrations of conjugated linoleic acid in milk were highest in the fish oil (2.30 g/100 g of fatty acids) and fish oil with extruded soybean (2.17 g/100 g of fatty acids) diets compared with the control (0.56 g/100 g fatty acids) diet. Milk, cream, butter, and buttermilk from the fish oil, fish oil with extruded soybean, and extruded soybean diets had higher concentrations of transvaccenic acid and unsaturated fatty acids compared with the controls. Butter made from the extruded soybean diet was softest compared with all treatments. An experienced sensory panel found no flavor differences in milks or butters.

Animal Feed↗
PubMed2005

Studies on the development of potential biomarkers for rapid assessment of copper toxicity to freshwater fish using Esomus danricus as model.

Living in an environment that has been altered considerably by anthropogenic activities, fish are often exposed to a multitude of stressors including heavy metals. Copper ions are quite toxic to fish when concentrations are increased in environmental exposures often resulting in physiological, histological, biochemical and enzymatic alterations in fish, which have a great potential to serve as biomarkers. Esomus danricus was chosen as model in the present study and the metabolic rate, gill morphology, total glycogen, total protein, superoxide dismutase and catalase were critically evaluated. The 96h LC50 value was found to be 5.5mg/L (Cu as 1.402 mg/L). Fish groups were separately exposed to lethal (5.5 mg/L) and sub lethal concentrations (0.55 mg/L) of copper sulphate over a period of 96h to examine the subtle effects caused at various functional levels. Controls were also maintained simultaneously. Significant decrease in the metabolic rate (p<0.001) of the fish was observed in both the concentrations studied. Studies employing Automated Video Tracking System revealed gross changes in the architecture of gill morphology like loss, fusion, clubbing of secondary gill lamellae, and detachment of gill rakers following softening of gill shaft in fish under lethal exposures indicating reduced respiratory surface area. Biochemical profiles like total glycogen and total protein in gills and muscle of fish exposed to 5.5 mg/L showed appreciable decrease (p<0.05 to 0.001) from control. Significant inhibition of superoxide dismutase (60.83%), catalase (71.57%) from control was observed in fish exposed to 5.5 mg/L at the end of 96h exposure only. Interestingly, in fish exposed to 0.55 mg/L enzyme activity is not affected except for catalase. Toxic responses evaluated at various functional levels are more pronounced in fish exposed to 5.5 mg/L and these can serve as potential biomarkers for rapid assessment of acute copper toxicity in environmental biomonitoring.

Animals↗
PubMed1989

[Effect of fish oil diet on activities of lipogenic enzymes and glucose-6-phosphatase in rat liver and adipose tissue].

In order to evaluate the effect of fish oil on lipid hydrogenase(G6PDH), malic enzyme(ME), glucose-6-phosphatase(G6Pase) activities were measured in liver and adipose tissue of rats fed 13 days supplemented fish oil at the level of 10% (W/W). Two other groups of rats were fed 10% soybean oil or lard to compare with the effect of fish oil. In all groups, activities of hepatic G6PDH and ME were depressed from the beginning of feeding. This effect was greatest (50%) in fish oil group. Hepatic G6Pase was highest in rats fed lard. When the level of fish oil was reduced to half, as total fat content was maintained at the level of 10% by complementary lard, lipogenic enzyme depressing effect of fish oil was as significant as shown in 10% fish oil diet. Hepatic G6PDH was depressed significantly (14%) in rats fed fish oil as low as 2%. On the other hand, changes in adipose tissue G6PDH and ME activities were small. Adipose tissue G6PDH activity increased slightly in rats fed with increasing fish oil(above 0.5%). It is suggested that fish oil alter, more markedly than either soybean oil or lard, cellular lipid metabolism by reducing activities of hepatic lipogenic enzymes.

Adipose Tissue↗
PubMed2002

Short-term effects of fish oil treatment on urinary excretion of high- and low-molecular weight proteins in patients with IgA nephropathy.

AIMS: Recently, it was shown that fish oil treatment improved renal survival in patients with IgA nephropathy. The precise mechanisms of this protective effect remained unclear. Omega-3 polyunsaturated fatty acids (PUFAs), important active substances of fish oil, are able to attenuate inflammatory responses. Thus, the renoprotective effects of fish oil may be the result of mitigation of glomerular or tubulo-interstitial inflammation. We hypothesized that such a decrease in glomerular or tubulo-interstitial inflammation could result in an improvement of glomerular permselectivity as reflected by the urinary excretion of IgG, or of tubular reabsorption capacity as reflected by the urinary excretion of low-molecular weight proteins (LMWPs), or a decrease of the excretion of the inflammatory mediators MCP-1 and TNF-alpha. METHODS: Twelve patients with a biopsy-proven IgA nephropathy, a persistent proteinuria of > 0.5 g/24 h, and an impairment of renal function (creatinine clearance 44 ml/min/1.73 m2, range 19-72) were treated with fish oil for 6 months. The daily dosage of PUFAs amounted to 3.0 g. Before start of treatment (month 0), at the end of treatment (month 6), and 6 months off treatment (month 12), renal measurements were carried out. Creatinine clearance (ECC) was measured after pretreatment with cimetidine. In timed urine samples albumin, IgG, the LMWPs beta2-microglobulin and alpha1-microglobulin, and both MCP-1 and TNF-alpha were measured. RESULTS: Six months of fish oil treatment had no effect on creatinine clearance (44 ml/min/1.73 m2 vs 42 ml/min/1.73 m2), the urinary excretion of albumin (1,594 +/- 284 vs 1,370 +/- 337 microg/min), IgG (84 +/- 16 vs 82 +/- 20 microg/min), beta2-microglobulin (medians: 1.0 vs 0.8 microg/min), alpha1-microglobulin (38 +/- 9 vs 53 +/- 15 microg/min), MCP-1 (medians: 720 vs 782 microg/min), or TNF-alpha (medians: 31 vs 27 microg/min). Mean arterial pressure gradually decreased from 102 +/- 4 to 96 +/- 4 mmHg at the end of the treatment (n.s.), however, the lowest value was observed after fish oil had been stopped for 6 months (93 +/- 3 mmHg, p < 0.05). Changes in the excretion of the urinary proteins during the 12-month study period were correlated to changes in blood pressure (r = 0.57, p < 0.01), independent of fish oil treatment. The course of the disease over the 12-month study period in our fish oil-treated patients was comparable to that of an untreated control group. CONCLUSIONS: Fish oil treatment in patients with IgA nephropathy, renal insufficiency and proteinuria did not affect the excretion of low- or high-molecular weight proteins, MCP-1 or TNF-alpha. Our data do not provide arguments for beneficial effects of fish oil treatment on glomerular permselectivity of tubulo-interstitial inflammation.

Adult↗
PubMed1999

Fish p53 as a possible biomarker for genotoxins in the aquatic environment.

The p53 gene is a tumour suppressor gene which has a fundamental role in cell cycle control and division, and in mammals certain genotoxic agents induce specific mutations in p53, leading to tumourigenesis. Fish have been investigated as models for studying carcinogens, but as yet very little data exists that links exposure to specific chemicals with the aetiology of tumours found in wild populations. In this study, p53 was sequenced from five species of fish with a view to the possible use of mutations in the highly conserved domains of p53 to identify genotoxins in the aquatic environment. A 0.8 kb fragment of the cDNA encompassing the conserved DNA-binding domain of p53 was sequenced in three Oncorhynchus salmonid fish: coho (O. kisutch), chum (O. keta), and chinook (O. tshawytscha) and full-length p53 cDNAs were sequenced in the puffer fish (Tetraodon miurus) and the barbel (Barbus barbus). The full-length puffer fish and barbel p53 cDNAs were 1834 bp and 1790 bp in length, encoding a 367 aa protein and a 369 aa protein, respectively. The deduced aa sequences of the p53 cDNA in the Oncorhynchus salmon shared a 100% identity in the five conserved regions (I-V). Comparisons of the deduced aa sequences for puffer fish and barbel p53 with other fish p53s revealed a high homology within the conserved DNA binding domain (68-86% for puffer fish and between 66-88% for barbel). "Conserved" domain I was not highly conserved in fish, as it is in mammals, and, therefore, conserved domains II-V are most likely to provide the valuable sequences in fish p53 for use in mutational studies to fingerprint genotoxins in the aquatic environment.

Amino Acid Sequence↗
PubMed2002

Lamina-associated polypeptide 2 (LAP2) expression in fish and amphibians.

Somatic and germinal cells of 15 fish and 33 amphibian species were examined by SDS-PAGE followed by immunoblotting to determine the expression of LAP2 (lamina-associated polypeptide 2). LAP2 expression in frogs, salamanders and fish does not vary with the mode of reproduction. In fish and frog cells, a rim-like LAP2 positive region was detected around the nucleus by indirect immunofluorescence microscopy. The cell distribution and expression patterns of LAP2 in fish, frogs and salamanders are comparable with those found in Xenopus and zebrafish. The mammalian somatic cell pattern, which may also occur in gymnophione amphibians, includes LAP2alpha, beta and gamma as major isoforms, whereas LAP2alpha does not occur in cells of fish, frogs and salamanders. In fish, LAP2gamma is the major isoform of somatic cells, suggesting that LAP2gamma may be ancestral. However, in the rainbow trout, as in frogs and salamanders, LAP2beta was the major somatic isoform. Fish and frog sperm only express low molecular weight polypeptides. In contrast, fish and frog oocytes express an oocyte-specific LAP2 isoform of high molecular weight. In the toad Bufo marinus this isoform becomes upregulated in pre-vitellogenic oocytes of 150-200 microm in diameter. The absence of LAP2alpha and the differential expression of LAP2 isoforms in somatic and germ cells, as found in fish and frogs, may be ancestral vertebrate characters. In spite of differences in developmental time, the LAP2 isoforms of somatic cells are upregulated during gastrulation, suggesting that LAP2 may be implicated in the early development of fish and frog.

Animals↗
PubMed2002

Long-term effect of fish oil diet on basal and stimulated plasma glucose and insulin levels in ob/ob mice.

In this study, the ob/ob mouse model was used to investigate epidemiological evidence linking fish intake to relative reduction in incidence of Type 2 diabetes mellitus and glucose. We have investigated, in comparison to low and high fat diets, the effect of a fish oil diet on basal and stimulated plasma glucose and insulin levels in male and female ob/ob mice. Mice were fed for 12 months with a saturated fat diet containing 25% lard, with a low fat diet containing 5% soybean oil, with a polyunsaturated fat diet containing 25% safflower seed oil (n-6) or with polyunsaturated fat diet containing 23% fish oil (n-3). Total body weight increased to approximately 100 g at the end of the experiment, with the highest increase in the order of lard > safflower oil > fish oil > soybean oil diet. Intercurrent deaths were found especially in the fish oil diet group. Compared to the other diet groups, plasma insulin levels of the fish oil diet group were significantly increased 3 months after the start of the diet and remained higher for another 3 months. Thereafter, the level declined to those of the other diet groups. Glucose-tolerance tests at 3, 6, 8 and 10 months showed a tendency of more efficient tissue glucose uptake in the fish oil group compared to the other groups, which was in accordance with a higher plasma insulin levels. At 12 months, microscopy revealed an increased severity of hepatic brown pigment accumulation and extramedullary haematopoiesis in the spleen of mice fed with fish oil. We conclude that fish oil diet in ob/ob mice reduced the body weight gain and increased the glucose-induced insulin secretion. Fish oil diet also increased intercurrent mortality. However, a consistent course of death could not be established using morphological parameters.

Animals↗
PubMed2002

Modeling fish community dynamics in the Florida Everglades: role of temperature variation.

Temperature variation is an important factor in Everglade wetlands ecology. A temperature fluctuation from 17 degrees C to 32 degrees C recorded in the Everglades may have significant impact on fish dynamics. The short life cycles of some of Everglade fishes has rendered this temperature variation to have even more impacts on the ecosystem. Fish population dynamic models, which do not explicitly consider seasonal oscillations in temperature, may fail to describe the details of such a population. Hence, a model for fish in freshwater marshes of the Florida Everglades that explicitly incorporates seasonal temperature variations is developed. The model's main objective is to assess the temporal pattern of fish population and densities through time subject to temperature variations. Fish population is divided into 2 functional groups (FGs) consisting of small fishes; each group is subdivided into 5-day age classes during their life cycles. Many governing sub-modules are set directly or indirectly to be temperature dependent. Growth, fecundity, prey availability, consumption rates and mortality are examples. Several mortality sub-modules are introduced in the model, of which starvation mortality is set to be proportional to the ratio of prey needed to prey available at that particular time step. As part of the calibration process, the model is run for 50 years to ensure that fish densities do not go to extinction, while the simulation period is about 8 years. The model shows that the temperature dependent starvation mortality is an important factor that influences fish population densities. It also shows high fish population densities at some temperature ranges when this consumption need is minimum. Several sensitivity analyses involving variations in temperature terms, food resources and water levels are conducted to ascertain the relative importance of temperature dependence terms.

Animals↗
PubMed1992

Rapid facile solid-phase immunobead assay for screening ciguatoxic fish in the market place.

The precision of the solid-phase immunobead assay (Ciguatect) to detect toxins associated with ciguatera poisoning have been evaluated through analysis of toxic and non-toxic fish obtained from fishing areas around the Hawaiian Islands. The Ciguatect test kit has been optimized for application to field/marketplace screening of ciguatoxic fish. Twelve parrot, surgeon, and amberjack fish fillet and fish extract test portions containing various concentrations of toxins were distributed to participating laboratories for analysis. The presence or absence of ciguatera-related toxins is determined by binding the toxins to a membrane attached to a plastic strip and exposing the toxin ladened membrane to a monoclonal antibody-colored latex bead complex which has a high specificity for ciguatera-related toxins. The intensity of the color on the membrane denotes the presence of the toxins in the fish or fish extract. Toxic components in the fish were confirmed by extraction, column purification, and toxicity testing using the brine shrimp (Artemia sp.) assay. Okadaic acid was used to standardize both the S-PIA and brine shrimp assays. For determination of ciguatoxin and related polyether toxins in parrot, surgeon, and amberjack fish fillets, the relative standard deviations for repeatability (RSDR) were 13.5, 9.0 and 4.3%, respectively, and the relative standard deviations for reproducibility (RSDR) were 44.4, 29.7 and 14.3%, respectively, for concentrations ranging from 1-4 ng/test strip. For determination of ciguatoxin and related polyether toxins in parrot, surgeon, and amberjack fish extracts, the RSDR were 5.8, 4.8, and 3.7%, respectively, and the RSDR were 11.9, 9.9, and 7.6%, respectively, for concentrations ranging from 3-5 ng/test strip.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

[Correlation of mercury, selenium and other elements in the tissues of fishes from the regions at different mercury exposure level].

The contents of selenium and other elements in fish liver and muscle tissues collected from mercury polluted area of Wanshan, Guizhou province of China and non-known mercury polluted one of Beijing were determined with instrumental neutron activation analysis, and that of mercury was determined with atomic fluorescence spectrometry. The correlation among the determined elements, especially between mercury and selenium, in the fish tissues were studied. For most of the elements significant difference of elemental content was found between tissues of liver and muscle, and mostly the content in liver was higher than that in muscle. It was interesting to note that the average content of mercury in Guizhou fish liver was 25-fold higher than that in Beijing one, and 5-fold higher in Guizhou fish muscle than that in Beijing one. For most of the elements no significant difference on the average content was found between the same tissues of the two areas. The molar ratio of Hg/Se increased with the increasing of Hg content at the low Hg level, but the alteration trend became gently and reached to a higher constant value (about 0.2) at the higher Hg level. Only the element of bromine and rubidium was found to have strong linear correlation between the two different tissues of liver and muscle. Though certain correlation existed among the different elements of fish tissues from the two areas, the most significant and the closest one existed between the mercury and selenium of muscle tissue of Guizhou fishes. A closer correlation was also found between them of liver tissue of Guizhou fishes. As for Beijing fish tissues, the correlation of mercury and selenium only existed in liver but no correlation of them was found in muscle. Our results confirm the fact that a certain interaction exists between mercury and selenium in organisms including fish, and it is more evident as the mercury-exposed level is higher. Some significant correlation was also observed between other elements, such as potassium and sodium, cesium and rubidium, iron and zinc, in fish tissues and it could be well explained by their similar chemical and physical properties or their different biological functions.

Animals↗