Search results for "Herring"
showing 10 items of 34 documents
Effect ofMicrocystis aeruginosa andNodularia spumigena on survival ofEurytemora affinis and the embryonic and larval development of the Baltic herrin…
2003
Laboratory experiments were carried out to investigate the effect of two strains of Microcystis aeruginosa and a strain of Nodularia spumigena on the survival of Eurytemora affinis (Copepoda) and on the embryonic and larval development of the Baltic spring-spawning herring Clupea harengus membras. The trials were made in water taken from Parnu Bay, at a salinity of 3.7–5.1 psu, a constant temperature (15°C ± 1°C in trials with Eurytemora and herring embryos; 18°C ± 2°C with herring larvae), and an oxygen concentration of 8.8–10.4 ppm. The strains tested had a negative impact on the survival of Eurytemora, as well as on the embryonic development and hatching regime of the Baltic herring. In …
Human Dietary Intake of Organochlorines from Baltic Herring: Implications of Individual Fish Variability and Fisheries Management
2007
This study examines the extent to which Finnish human dietary intake of organochlorines (PCDD/Fs and PCBs) originating from Northern Baltic herring can be influenced by fisheries management. This was investigated by estimation of human intake using versatile modeling tools (e.g., a herring population model and a bioenergetics model). We used a probabilistic approach to account for the variation in human intake of organochlorines originating from the variation among herring individuals. Our estimates were compared with present precautionary limits and recommendation for use. The results show that present consumption levels and frequencies of herring give a high probability of exceeding recom…
Biomagnification of organohalogens in Atlantic salmon (Salmo salar) from its main prey species in three areas of the Baltic Sea
2012
Abstract Factors affecting the biomagnification of organohalogens in Baltic salmon from sprat, herring and three-spined stickleback were assessed in three feeding areas. Second sea-year salmon contained (in fresh weight of whole fish) 79–250 ng g− 1 polychlorinated biphenyls (ΣPCB), 0.9–2.7 pg g− 1 dibenzo-p-dioxins (ΣPCDD), 8–19 pg g− 1 dibenzofurans (ΣPCDF), 96–246 pg g− 1 coplanar PCBs, 2.4–3.6 ng g− 1 polybrominated diphenylethers (ΣPBDE), and 39–136 ng g− 1 Σindicator PCB6. The EU limits for WHO toxic equivalent concentrations in fish feed were already exceeded in one-year-old sprat and herring and were exceeded many-fold in older age groups. The differences in the biomagnification rat…
Growth and food utilisation of rainbow trout (Oncorhynchus mykiss) fed low-fat herring and dry diets enriched with fish oil
1998
Two-year-old rainbow trout (initial weight 695 g) were fed for 15 weeks low-fat Baltic herring diets either with or without lipid enrichment. For comparison, similar groups of trout were fed dry pellets with and without top-dressing with fish oil. Inclusion of lipid increased growth rate in a similar manner for both types of diets. For the herring-based diet, increased lipid resulted in increased dry matter consumption but for the dry diet, feed efficiency (dry weight growth per dry weight food consumption) was improved by channelling more nutrients to lipid deposition. If compared within a stated lipid level, fish fed the herring-based diets grew at a slower rate than fish fed the dry diet…
Potential predation pressure of littoral mysids on herring (Clupea harengus membras L.) eggs and yolk-sac larvae
2008
The predation potential of littoral mysid shrimps (Mysidacea) on Baltic herring (Clupea harengus membras L.) eggs and yolk-sac larvae was studied experimentally. The results showed that littoral mysids feed actively on both eggs and yolk-sac larvae. It was shown that Neomysis integer preys on eggs, which are not attached to the substrate. Alternative food (yolk-sac larvae or zooplankton) did not decrease feeding rate on eggs. Only gravel as a bottom material lowered the ingestion rate to nearly zero. The largest of the mysid species Praunus flexuosus ate yolk-sac larvae more than other mysids and most efficiently. Mysids switched to feed on eggs when larvae and eggs were offered simultaneou…
Redescription and new records of the monotypic genus Trynocoris Herring, 1976 (Heteroptera: Miridae: Cylapinae: Fulviini).
2019
Trynocoris lawrencei Herring, the only representative of the genus Trynocoris and only known from Barro Colorado Island, Canal Zone, Panama, is recorded for the first time from Mexico, Nicaragua, Panama: Chinqui and Ecuador. Redescription of the genus and species are given along with color photographs of the adults, scanning electron micrographs of selected structures of T. lawrencei. Illustrations of the tarsi and male genitalia are presented for the first time.
Effects of gender, diet, exogenous melatonin and subchronic PCB exposure on plasma immunoglobulin G in mink
2002
Abstract Effects of different fish-based diets (freshwater smelt, Baltic herring, marine herring/cod offal or their mixtures), gender, β-glucan supplement, exogenous melatonin, and PCB exposure (Aroclor 1242®, 1 mg per animal per day in feed) on plasma immunoglobulin G (IgG) in the mink (Mustela vison) were studied. The aims of the study were to find out whether plasma IgG of the mink is affected by the subchronic PCB exposure, and whether biological, nutritional and hormonal effects are large enough to mask the possible IgG response. The concentration of IgG was determined using enzyme-linked immunosorbent assay (ELISA). Sexual dimorphism was detected, the males having higher levels of pla…
Seasonal dynamics of atlantic herring (Clupea harengus L.) populations spawning in the vicinity of marginal habitats
2014
Published version of an article from the journal PLoS One. Also available from the publisher: http://dx.doi.org/10.1371/journal.pone.0111985 Gillnet sampling and analyses of otolith shape, vertebral count and growth indicated the presence of three putative Atlantic herring (Clupea harengus L.) populations mixing together over the spawning season February–June inside and outside an inland brackish water lake (Landvikvannet) in southern Norway. Peak spawning of oceanic Norwegian spring spawners and coastal Skagerrak spring spawners occurred in March–April with small proportions of spawners entering the lake. In comparison, spawning of Landvik herring peaked in May–June with high proportions f…
Growth and emigration of third-stage larvae of Hysterothylacium aduncum (Nematoda: Anisakidae) in larval herring Clupea harengus
2000
The growth and emigration of Hystherothylacium aduncum in laboratory-reared herring larvae Clupea harengus was studied. Experimental infections of 36-day-old herring larvae resulted in 126 hosts infected with 306 H. aduncum larvae. Regression analyses showed a significant worm emigration from the rectum to the head of the fish, accompanied by an increase in worm body length. The emigration was independent of worm intensity, which suggests an ontogenetic process. Some worms departed from this pattern by moving posteriorly or by penetrating into the muscle, and in 5 cases, the larvae were observed to leave living fish. This individual variation has not been observed in previous studies and mi…
Ring species – Do they exist in birds?
2007
Abstract According to current theory, the splitting of a single species into two is best observed by a ring of intergrading populations which occupy a ring-shaped distribution area and whose terminal populations not only meet but overlap and co-occur without or with only little hybridization. The three most discussed examples in birds are revisited here. The great tit complex ( Parus major s. l.) turned out to be an assemblage of four subspecies groups forming a secondary ring of population. The herring gull/lesser black-backed gull complex ( Larus argentatus s. l.) forms a circumpolar circle of intergrading populations, but lacks the crucial cornerstone, the geographical overlap. The green…