Total Fish Consumption Research Articles

Habitual fish consumption and risk of incident stroke: the European Prospective Investigation into Cancer (EPIC)–Norfolk prospective population study

To examine the association between fish consumption and stroke risk. Prospective population cohort study. Norfolk, UK cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk). Subjects were 24 312 men and women aged 40-79 years who had no previous history of stroke at baseline. Fish consumption was assessed using a food-frequency questionnaire at baseline in 1993-1997 and stroke incidence ascertained to 2004. A total of 421 incident strokes were identified (mean follow-up=8.5 years, total person-years=209 238). There were no significant relationships between total fish, shellfish or fish roe consumption and risk of stroke in men and women after adjusting for age, systolic blood pressure, body mass index, smoking, cholesterol, diabetes, physical activity, alcohol consumption, fish oil supplement use and total energy intake using Cox regression analyses. Oily fish consumption was significantly lower in women who subsequently had a stroke (odds ratio (OR) for consumers vs. non-consumers=0.69, 95% confidence interval (CI) 0.51-0.94, P=0.02). The trend in men was similar but not significant (OR for consumers vs. non-consumers=0.88, 95% CI 0.65-1.19, P=0.41). There was no consistent relationship between fish consumption and stroke in this British population. Inconsistencies in the observed health effects of fish consumption in different populations may reflect different patterns and type of fish consumed and preparation methods.

Maternal fish consumption, mercury levels, and risk of preterm delivery.

BackgroundPregnant women receive mixed messages about fish consumption in pregnancy because unsaturated fatty acids and protein in fish are thought to be beneficial, but contaminants such as methylmercury may pose a hazard.MethodsIn the Pregnancy Outcomes and Community Health (POUCH) study, women were enrolled in the 15th to 27th week of pregnancy from 52 prenatal clinics in five Michigan communities. At enrollment, information was gathered on amount and category of fish consumed during the current pregnancy, and a hair sample was obtained. A segment of hair closest to the scalp, approximating exposure during pregnancy, was assessed for total mercury levels (70–90% methylmercury) in 1,024 POUCH cohort women.ResultsMercury levels ranged from 0.01 to 2.50 μg/g (mean = 0.29 μg/g; median = 0.23 μg/g). Total fish consumption and consumption of canned fish, bought fish, and sport-caught fish were positively associated with mercury levels in hair. The greatest fish source for mercury exposure appeared to be canned fish. Compared with women delivering at term, women who delivered before 35 weeks’ gestation were more likely to have hair mercury levels at or above the 90th percentile (≥ 0.55 μg/g), even after adjusting for maternal characteristics and fish consumption (adjusted odds ratio = 3.0; 95% confidence interval, 1.3–6.7).ConclusionThis is the first large, community-based study to examine risk of very preterm birth in relation to mercury levels among women with low to moderate exposure. Additional studies are needed to see whether these findings will be replicated in other settings.

Organochlorines in Danish women: Predictors of adipose tissue concentrations

Organochlorines (OCs) are ubiquitously present in the environment, and food of animal origin is currently reported as the major source of exposure. Carcinogenicity in animals raises concern, and OCs may also be a risk factor for both neurological and immunological effects. Our primary objective was to study predictors of adipose tissue levels of dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) in Danish women. We showed that adipose tissue concentrations of DDE and PCBs were consistently positively associated with age and the consumption of fish with a high fat content, while total lifetime duration of lactation had an inverse relationship. The direction of the association with body mass index (BMI) depended on the OC studied. The consumption of meat, fruit, lean fish, medium-fat-content fish, poultry, and eggs was not associated with OC concentrations in our study. We classified fish according to fat percentage, which seems more relevant than considering only total fish consumption. When PCBs were subdivided according to their chemical structure, similar results were obtained for the mono-, di-, and tri- ortho PCBs, indicating that PCBs can be treated as a homogenous group when studying predictors of concentrations in humans. In conclusion, the present study shows that age, lactation, and BMI are consistent predictors of human adipose tissue concentrations of DDE and PCBs and that dietary factors other than fish with a high fat content are not important predictors of these concentrations.

FISH CONSUMPTION AND FOOD SECURITY: A DISAGGREGATED ANALYSIS BY TYPES OF FISH AND CLASSES OF CONSUMERS IN SELECTED ASIAN COUNTRIES

ABSTRACT This paper discusses fish consumption and preference patterns for fish species by income groups, and by urban/rural divide in Bangladesh, China, India, Indonesia, the Philippines, Thailand, and Vietnam. The analysis is based on primary data collected by the WorldFish Center and its partner institutes by means of a survey of 5,931 households in the selected countries. The FAO database and other published materials were also used to analyze trends in fish consumption. Freshwater fish species constitute a major share in total per capita fish consumption in most of these countries. Pelagic and demersal marine fish are the main contributor to per capita total fish consumption in the countries with longer coastal boundaries (such as Indonesia, the Philippines and Thailand), and in the coastal regions within each country. Results suggest that fish contributes between 15% and 53% of the total animal protein intake in these countries. Fish consumption varies widely with economic position of the households, in terms of both per capita consumption and type of fish species. Per capita fish consumption increases with increase in income. The share of fish protein in total animal protein expenditure is higher for lower income groups, demonstrating their dependence on fish as a source of animal protein. Poor people consume mostly low-price fish and rich people spend a significant portion of their fish budget on expensive fish. Per capita fish consumption is substantially higher in rural areas than in urban areas.

Methyl mercury exposure in Swedish women with high fish consumption

We studied the exposure to methyl mercury (MeHg) in 127 Swedish women of childbearing age with high consumption of various types of fish, using total mercury (T-Hg) in hair and MeHg in blood as biomarkers. Fish consumption was assessed using a food frequency questionnaire (FFQ), including detailed information about consumption of different fish species, reflecting average intake during 1 year. We also determined inorganic mercury (I-Hg) in blood, and selenium (Se) in serum. The average total fish consumption, as reported in the food frequency questionnaire, was approximately 4 times/week (range 1.6–19 times/week). Fish species potentially high in MeHg, included in the Swedish dietary advisories, was consumed by 79% of the women. About 10% consumed such species more than once a week, i.e., more than what is recommended. Other fish species potentially high in MeHg, not included in the Swedish dietary advisories, was consumed by 54% of the women. Eleven percent never consumed fish species potentially high in MeHg. T-Hg in hair (median 0.70 mg/kg; range 0.08–6.6 mg/kg) was associated with MeHg in blood (median 1.7 μg/L; range 0.30–14 μg/L; r s=0.78; p<0.001). Hair T-Hg, blood MeHg and serum Se (median 70 μg/L; range 46–154 μg/L) increased with increasing total fish consumption ( r s=0.32; p<0.001, r s=0.37; p<0.001 and r s=0.35; p=0.002, respectively). I-Hg in blood (median 0.24 μg/L; range 0.01–1.6 μg/L) increased with increasing number of dental amalgam fillings. We found no statistical significant associations between the various mercury species measured and the Se concentration in serum. Hair mercury levels exceeded the levels corresponding to the EPA reference dose (RfD) of 0.1 μg MeHg/kg b.w. per day in 20% of the women. Thus, there seems to be no margin of safety for neurodevelopmental effects in fetus, for women with high fish consumption unless they decrease their intake of certain fish species.

Reliability of sport fish consumption in the New York State Angler Cohort Study

This paper examines the reliability of sport fish consumption data from the New York State Angler Cohort Study (NYSACS). NYSACS is a prospective cohort study conducted among New York State registered sportsmen and fishermen. Sport fish consumption information for New York State waters including the Great Lakes between June 1990 and June 1991 were collected through self-administered questionnaires, Spouses of male anglers were asked to provide their husbands’ fish consumption during the same time period. A short telephone interview after the cohort was ascertained was also conducted among about 100 study participants for the purpose of quality control. Percentage agreement, kappa, and weighted kappa were calculated to evaluate the reliability of the interview using spousal data and reinterview data. Overall, for the total fish consumption between June 1990 and June 1991, percentage agreement, kappa, and weighted kappa between spousal data and primary response were 67.28%, 0.5087, and 0.6157, respectively. For reinterview data, weighted kappa ranged from 0.4510 to 0.5285 for season-specific analysis and kappa ranged from 0.4615 to 0.7006 for fish species-specific analysis. Spouses may be a good source of proxy data for fish consumption. The reliability of sport fish consumption data for the NYSACS study is acceptable, suggesting that the food frequency measuring methods employed are a viable approach to obtain retrospective sport fish consumption data from sportsmen and subsistence anglers.

Exposure assessment and initial intervention regarding fish consumption of tribal members of the Upper Great Lakes Region in the United States

The Ojibwe Health Study (OHS) has concluded 10 years of data collection and exposure assessment. Eight hundred and twenty-two participants from tribes in the states of Wisconsin, Michigan, and Minnesota (USA) completed fish consumption and environmental risk perception questionnaires. Many participants provided hair and blood samples for mercury and polychlorinated biphenyl (PCB) residue analyses as body burden indicators of these persistent environmental pollutants. Fish were collected by the tribal organizations and contaminants were analyzed for numerous tribal reports and professional environmental journal articles, these data were used by the Great Lakes Indian Fish and Wildlife Commission to produce tribal-specific geographic information systems maps as part of a public health intervention strategy. These maps are currently available at www.glifwc.org for six Wisconsin tribes that regularly harvest walleye. To determine the health impacts (if any) of pollutants on cancer, diabetes, and reproduction, it was necessary to know the recent trends in key indicators such as cancer mortality ratios and birth gender ratios. The Great Lakes Inter-Tribal Council provided the OHS and each participating tribe in Wisconsin and Michigan with a health profile. Total fish consumption (estimated by recall) for 720 tribal participants was self-reported as 60 g/day, but the highest actual consumption was measured as 11.2 g/day in one of the tribal groups. The highest blood concentrations in tribal participants were 18.6 ppb total serum PCBs and 11.8 ppb total blood mercury. Ninety percent of the participants had less than 3.8 ppb total serum PCBs and 2.6 ppb total blood mercury. Compared to other studies of subsistence fishing populations, these exposures were only moderately elevated and not high enough to warrant widespread restrictions on diets. Furthermore, the benefits of eating a fish diet must be continually emphasized. However, sport fishermen and their families who consume larger and more contaminated fish should abide by their state fish consumption advisories to minimize their health risks.

Fish-seafood consumption, obesity, and risk of type 2 diabetes: an ecological study

There is substantial evidence that type 2 diabetes increases with the degree and duration of obesity. This study was conducted to examine the association, at the international level, between fish and seafood consumption and the prevalence of type 2 diabetes, taking into account the prevalence of obesity. An ecological study of 41 countries in five continents with different socio-demographic characteristics and sanitary conditions was carried out. Data on the prevalence of diabetes and obesity as well as food balance sheets were collected from websites. Correlations between the variables studied were followed by an exploration of their interaction. After adjustment for total energy intake, there was a significant correlation (rho=0.81, P<0.0001) between the prevalence of type 2 diabetes in the 20- to 44- and 45- to 64-year age groups. Type 2 diabetes in the 45- to 64-year age group was about 5 times higher than in the 20- to 44-year age group. Obesity was positively associated with type 2 diabetes in both age groups (rho=0.39; P=0.012 and rho=0.48; P=0.002 in the 20- to 44- and 45- to 64-year age groups, respectively). An interaction effect was found between diabetes, obesity and total fish and seafood consumption. In countries with low fish and seafood consumption, the prevalence of type 2 diabetes increased significantly with obesity (0.8 +/- 0.3% vs. 2.5 +/- 1.8%; P=0.002 and 3.3 +/- 2.6% vs. 11.0 +/- 3.9%; P<0.0001 for the 20- to 44- and 45- to 64-year age groups, respectively). In countries with a greater prevalence of obesity, there was evidence of significantly reduced type 2 diabetes with high fish and seafood consumption (2.5 +/- 1.8% vs. 0.9 +/- 0.7%; P=0.007 and 11.0 +/- 3.9% vs. 6.2 +/- 4.1%; P=0.041 for the 20- to 44- and 45- to 64-year age groups, respectively). The results of this study suggest that high fish and seafood intake may reduce the risk of type 2 diabetes in populations with a high prevalence of obesity.

Small Indigenous Fish Species in Bangladesh: Contribution to Vitamin A, Calcium and Iron Intakes

Fish play an important role in the Bangladeshi diet, constituting the main and often irreplaceable animal source food in poor rural households. Fish consumption is dominated by wild small (length <25 cm) indigenous fish species (SIS). The vitamin A content in SIS varies, from <100 microg of retinol equivalents (RE)/100 g raw edible parts, to >2,500 microg RE/100 g raw edible parts in mola (Amblypharyngodon mola). The study addressed the dietary contribution of fish to vitamin A, calcium and iron intakes and the potential of integrating SIS, including mola, into existing carp polyculture ponds. Fish consumption (wild and cultured fish) was surveyed by 5-d recall interviews in 84 poor rural households in Kishoreganj district in 1997-1998. Fifty-nine of the households cultured carp and SIS in small (mean size 400 m2) domestic ponds. Total household fish consumption was unaffected by the domestic aquaculture production. SIS from wild sources contributed 84% of the total fish consumption. In the peak season (October), SIS contributed 40% (median 23%) of the recommended vitamin A intake at the household level (n = 84). Thirty-four households cultured mola along with carp. Cultured mola used for household consumption contributed 20% (median 18%) of the recommended intake of vitamin A at the household level. Wild SIS is an important source of vitamin A and calcium in Bangladesh. Mola can be integrated in existing carp culture without negative effects and can contribute to increased vitamin A intake in rural households.

Decline in fish consumption among pregnant women after a national mercury advisory.

A well-publicized January 2001 federal advisory recommended that pregnant women limit consumption of certain fish because of concerns about mercury contamination. We endeavored to estimate the extent to which pregnant women changed fish consumption habits after dissemination of this national advisory. We performed interrupted time series analysis of data from a cohort of pregnant women (2235 who completed at least one dietary questionnaire) visiting obstetric offices in a multispecialty group practice in eastern Massachusetts, surveyed before the advisory from April 1999 through December 2000 and after the advisory from April 2001 through February 2002. Main outcome measures were consumption of total fish and of four fish types: canned tuna, dark meat fish, shellfish, and white meat fish. Subjects reported fish consumption on semiquantitative food frequency questionnaires administered at each trimester of pregnancy. We observed diminished consumption of dark meat fish, canned tuna, and white meat fish after the national mercury advisory. These decreases resulted in a reduction in total fish consumption of approximately 1.4 servings per month (95% confidence interval 0.7, 2.0) from December 2000 to April 2001, with ongoing declines through the end of the study period. There was no change in shellfish intake. After dissemination of federal recommendations, pregnant women in this cohort reported reduced consumption of fish, including tuna, dark meat fish, and white meat fish. Because these fish may confer nutritional benefits to mother and infant, public health implications of these changes remain unclear.

Decline in Fish Consumption Among Pregnant Women After a National Mercury Advisory

In Brief OBJECTIVE A well-publicized January 2001 federal advisory recommended that pregnant women limit consumption of certain fish because of concerns about mercury contamination. We endeavored to estimate the extent to which pregnant women changed fish consumption habits after dissemination of this national advisory. METHODS We performed interrupted time series analysis of data from a cohort of pregnant women (2235 who completed at least one dietary questionnaire) visiting obstetric offices in a multispecialty group practice in eastern Massachusetts, surveyed before the advisory from April 1999 through December 2000 and after the advisory from April 2001 through February 2002. Main outcome measures were consumption of total fish and of four fish types: canned tuna, dark meat fish, shellfish, and white meat fish. Subjects reported fish consumption on semiquantitative food frequency questionnaires administered at each trimester of pregnancy. RESULTS We observed diminished consumption of dark meat fish, canned tuna, and white meat fish after the national mercury advisory. These decreases resulted in a reduction in total fish consumption of approximately 1.4 servings per month (95% confidence interval 0.7, 2.0) from December 2000 to April 2001, with ongoing declines through the end of the study period. There was no change in shellfish intake. CONCLUSION After dissemination of federal recommendations, pregnant women in this cohort reported reduced consumption of fish, including tuna, dark meat fish, and white meat fish. Because these fish may confer nutritional benefits to mother and infant, public health implications of these changes remain unclear. Pregnant women reported reduced consumption of fish after dissemination of a federal advisory about the potential risks from mercury in seafood.

Variability of fish consumption within the 10 European countries participating in the European Investigation into Cancer and Nutrition (EPIC) study.

To describe and compare the consumption of total fish (marine foods) and the fish sub-groups - white fish, fatty fish, very fatty fish, fish products and crustacea, in participants from the European Investigation into Cancer and Nutrition (EPIC) study. Cross-sectional analysis of dietary intake using a computerised standardised 24-hour recall interview. Crude means, means and standard errors adjusted by age, season and day of the week were calculated, stratified by centre and gender. Twenty-seven redefined centres in the 10 European countries participating in the EPIC study. In total, 35 955 subjects (13 031 men and 22 924 women), aged 35-74 years, selected from the main EPIC cohort. A six- to sevenfold variation in total fish consumption exists in women and men, between the lowest consumption in Germany and the highest in Spain. Overall, white fish represented 49% and 45% of the intake of total fish in women and men, respectively, with the greatest consumption in centres in Spain and Greece and the least in the German and Dutch centres. Consumption of fatty fish reflected that of total fish. However, the greatest intake of very fatty fish was in the coastal areas of northern Europe (Denmark, Sweden and Norway) and in Germany. Consumption of fish products was greater in northern than in southern Europe, with white fish products predominating in centres in France, Italy, Spain, The Netherlands and Norway. Intake of roe and roe products was low. The highest consumption of crustacea was found in the French, Spanish and Italian centres. The number of fish types consumed was greater in southern than in northern Europe. The greatest variability in consumption by day of the week was found in the countries with the lowest fish intake. Throughout Europe, substantial geographic variation exists in total fish intake, fish sub-groups and the number of types consumed. Day-to-day variability in consumption is also high.

Dietary intakes and plasma organochlorine contaminant levels among Great Lakes fish eaters.

Nutritional intakes and contaminant burdens should be assessed jointly in individuals who are at high risk of environmental exposures to contaminants through food. In this study, the authors used shore surveys and community contacts to recruit 91 individuals who frequently consumed Great Lakes fish. These individuals provided dietary intake information and fasting blood samples for lipid and contaminant analyses. Participants ate an annual median of 88 meals of Great Lakes fish. Asian-Canadians consumed more total fish meals (i.e., Great Lakes, non-Great Lakes, and other) (medians = 213.0 females, 223.0 males) than Euro-Canadians (medians = 131.0 females, 137.5 males). The higher total fish consumption by Asian-Canadians was associated with a lower percentage of energy derived from fat, higher protein and iron intakes, and higher plasma concentrations of omega-3 essential fatty acids (e.g., median docosahexaenoic acid levels [microgram/l] in Asian-Canadian females = 5.48, males = 4.38; in Euro-Canadian females = 2.93, males = 2.27). Plasma organochlorine contaminant lipid weight concentrations varied by country of origin and by gender (e.g., median total polychlorinated biphenyls [microgram/kg] in Asian-Canadian females = 490.6, males = 729.0; in Euro-Canadian females = 339.6, males = 355.5). Age was the most consistent predictor (+ve) of contaminant concentrations, followed by years spent in Canada (for Asian-Canadians). Associations with sport fish consumption variables were less consistent than for the aforementioned predictors. Given both the health benefits and potential risks of fish consumption, policies that address diverse ethnocultural groups should support continued consumption of sport fish, but from less-contaminated sources than are currently used.

Changes in piscivory associated with fishing induced changes to the finfish community on Georges Bank

There are many ecologically and commercially important piscivores in the Georges Bank fish community. There has been a noticeable shift in the abundance of these predators during the last four decades which is generally attributed to fishing pressure. Although many fish persist as piscivores in this system, not only has their relative abundance changed but their size composition has also changed. Both factors influence the total magnitude of piscivory by these fish. To ascertain the cascading effects of fishing on fish predation, we examined relative abundance, total stomach contents, diet composition, consumption rates, and total food consumption of fish for several species across the time period. The proportion of the diet comprised by fish for piscivores on Georges Bank has remained remarkably consistent. However, the composition of specific fish prey has changed across the time series. Total fish consumption generally tracked predator abundance, but two species demonstrated compensating consumption rates as larger size classes declined. Contrary to our initial hypothesis, total fish consumption by six major predators has remained generally constant despite changes in predator size, structure and abundance. One reason for constant systemic piscivory is the dominant piscivore in this ecosystem has shifted from cod to spiny dogfish. We assert that a major effect of intense fishing pressure is a shift in energy flow for marine ecosystems.

A pooled analysis of case-control studies of thyroid cancer. VI. Fish and shellfish consumption.

To better understand the role of fish and shellfish on thyroid cancer risk, we systematically re-analyzed the original data from 13 case-control studies conducted in the US, Japan, China, and Europe. A total of 2497 cases (2023 women, 474 men) and 4337 controls (3268 women, 1069 men) were considered. Odds ratio (OR) and corresponding 95% confidence interval (CI) were estimated for each study by logistic regression models, conditioned on age and sex, and adjusted for history of goiter, thyroid nodules or adenomas, and radiation. Combined ORs were computed as the weighted average of the estimates from each study. The ORs for the highest level of total fish consumption (three or more times per week) as compared to the lowest one (less than once per week) was above unity in Hawaii, Connecticut, Japan, Norway, Tromsø, and Vaud. Conversely, the ORs for the studies in Los Angeles. Shanghai, southeastern Sweden, Uppsala, northern Sweden, northern Italy, and Athens were below one. The pattern of risk for salt water fish and shellfish was not substantially different from that of total fish. Fish was not associated with thyroid cancer risk in all studies combined (OR = 0.99, 95% CI 0.85-1.2 for moderate, and OR=0.88, 95% CI 0.71-1.1 for high total fish consumption), but there was a suggestion of a protective effect in endemic goiter areas (OR = 0.65, 95% CI 0.48-0.88). This combined analysis indicates that relatively elevated fish consumption does not appreciably increase thyroid cancer risk, and may have a favorable influence in areas where iodine deficiency is, or was, common.

An analysis of iodine deficiency disorder and eradication strategies in the high atlas mountains of morocco

The population of the Ounein Valley in the High Atlas Mountains in Morocco is at high risk of iodine deficiency. Food consumption habits, iodine deficiency and goiter patterns in local children were investigated through regression analysis using data from a household survey. Median urinary iodine content and goiter analysis both reflected moderate iodine deficiency in the population. Total fish consumption had a statistically significant, positive effect on urinary iodine content. Fish consumption, like that of salt, was closely related to market access. Respondents were generally unaware of the dietary etiology of goiter. An effective strategy to reduce the high incidence of iodine deficiency disorder among children in the valley must attend to four crucial issues: fish consumption, salt iodization, nutrition education, and market access.

Estimated Fish Consumption by Hooded Seals (Cystophora cristata), in the Gulf of St. Lawrence

Fish consumption by hooded seals (Cystophora cristata) in the Gulf of St. Lawrence was estimated by bringing together information on individual energy requirements, population size, distribution and diet composition. Aerial surveys indicated that pup production had increased from 2 006 (SE = 190) in 1991 to 3 978 (SE = 974) in 1994. A Leslie Matrix population model suggested that the population had increased from 10 000– 11 000 animals in 1991 to 11 000–16 000 animals in 1995, depending on the mortality rates used in the model. Individual daily energy requirements were estimated using the daily energy requirement, a daily growth increment, and the basal metabolic rate. Summing individual energy requirements over the period that hooded seals are thought to be in the Gulf of St. Lawrence, gave an increase in total fish consumption from 5 100–5 600 tons in 1991 to 5 600–8 400 tons in 1995. Assuming that the diet of the Gulf of St. Lawrence hooded seals was similar to that of animals collected off the Newfoundland coast, much of this consumption would have probably consisted of Greenland halibut (Reinhardtius hippoglossoides) and redfish (Sebastes sp.).

Comparison of Food Related Behavior of Individuals Based on Their Fat Intake

LEARNING OUTCOME: To examine the food-related behavior including food choices and practices of individuals with different levels of fat in diet.The main-meal planners of the U.S. Department of Agriculture 1989-91 Continuing Survey of Food Intake by Individuals /Diet and Health Knowledge Survey were used to study food related behavior in relation to fat intake. 4078 individuals with 3 day intake were categorized into three groups based on percent calories from fat There were 963 with 30% or less calories, 1548 between 30 and 37% calories, and 1567 over 37% calories from fat. Linear contrasts were used to test continuous variables (p < .015) and categorical variables were tested using chi-square (p < .05). SUDAAN software was used.There were no significant differences (p < .015) in total milk products, fish, poultry and total vegetable consumption among the three groups. However those with 30% or less calories from fat consumed significantly less whole milk, beef, sausages, luncheon meats, eggs, potatoes and table fats; and significantly more skim milk, yogurt, deep yellow vegetables, fruits, fruit juices, grains including rice and pasta than the other two groups. Higher percent of respondents with 30% or less fat calories “often” read food labels: 42% of them read label information on fat, 39% on cholesterol, 35% on sodium and 22% on fiber contents of the foods. They avoided whole milk (39%), red meat (21%), eggs (32%), and cheese (15%) in their diet; and replaced whole milk with low-fat or skim milk (73%), and whole eggs with egg whites (32%) in cooking (p < .05). This study shows individuals who have succeeded in lowering the fat level in their diet, read food labels more often than others, chose foods low in fats, eat more grains and fruits, and use low-fat food preparation methods. These strategies are useful to nutrition educators.

Seasonal patterns in the mortality of &lt;I&gt;Daphnia &lt;/I&gt; species in a shallow lake

To assess the impact of predation by young-of-the-year (0+) fish on the population dynamics of Daphnia species, we made independent estimations of the mortality of Daphnia species during the year, and of the predation pressure exerted by the juvenile fish. Mortality of daphnids was computed using a model that allowed us to differentiate between different size- classes, while total fish consumption was estimated from the temperature-dependent daily weight increase and the population development of the 0+ fish. The predation pressure on the different size-classes of Daphnia species was estimated by combining the total fish consumption with estimates of the selective feeding behaviour of the fish. To make the estimates of fish consumption independent of our current (1989-1991) zooplankton data set, we estimated fish species-specific and fish length-dependent selectivity indices on zooplankton using a different data set (1976-1977). Daphnia population densities usually increased in spring and decreased rapidly in early summer. Predation by 0+ fish was not severe enough to explain the large mortality that caused the summer decline; later in the year most of the mortality in the larger size-classes of the daphnids (>1.0 mm) could be explained by fish predation. [KEYWORDS: Young yellow perch; clear-water phase; body size; planktivorous fish; leptodora-kindti; neusiedler-see; eutrophic lake; hyalina leydig; birth-rate; zooplankton]

The production and trophic ecology of shallow-water fish assemblages in southern Australia II. Diets of fishes and trophic relationships between fishes and benthos at Western Port, Victoria

A total of 5113 fishes belonging to 91 species was collected from seagrass and unvegetated habitats at Western Port for dietary analysis between August 1989 and November 1990, with 720 animals having empty guts. None of the common species was found to have a highly specialised diet. Crustaceans were the dominant component in the diets of the majority (69%) of the 88 species with non-empty guts, with five species (a girellid, a mugilid, a monacanthid and two gobiids) consuming large amounts of algal material, and only one species [the garfish Hyporhamphus melanochir (Valenciennes)] ingesting seagrass in any quantity. In general, dietary differences between juveniles and adults of a species were as great as dietary differences between fish belonging to different species when at the same body size. Amongst the crustacean feeders, diets generally changed from predominantly copepods to predominantly peracarids (amphipods, isopods and mysids) at ≈0.1 g wet body weight, and from predominantly peracarids to predominantly crabs and shrimps at ≈100 g. Across the range of species examined, there was a close relationship between the size of ingested prey and fish biomass. Prey length averaged 7.5% of predator length. The dominant species in gillnet catches, the mullet Aldrichetta forsteri (Cuvier & Valenciennes), possessed an unusual diet because prey were smaller than for other fishes of the same body size and large quantities of algal material were also consumed. Similar trophic pathways leading to fishes were found in different habitats, with the major linkages being from benthic microalgae and detritus through epifaunal crustaceans to the smaller fishes. The major predators of small fishes were locally-resident species, the rock flathead Platycephalus laevigatus Cuvier & Valenciennes in seagrass beds and the sand flathead Platycephalus bassensis Cuvier & Valenciennes at unvegetated sites. Crustaceans supplied most of the dietary intake for the small fish communities at all sites, with molluscs and polychaetes also important but supplying >25% of food consumed at only two sites. When daily rates of consumption were compared with daily production of food, the production of crustaceans >1 mm sieve size was calculated to be all consumed by fish. The production of the non-crustacean benthos was an order of magnitude higher than that consumed by fish predators. These results indicate that the availability of high quality crustacean prey may limit the production of fishes, and that fishes are likely to compete diffusively for crustacean prey. Additional support for this hypothesis is provided by the observations that the condition of seagrass-associated fish declined, and mortality rates were high, during the autumn season when total fish consumption could not be supported by crustacean production.