Search results for "herring"
showing 10 items of 34 documents
Eight decades of adaptive changes in herring reproductive investment: the joint effect of environment and exploitation
2021
Abstract Reproductive investment is a central trait for population dynamics and productivity. Fishing and environmental variations are major drivers affecting population structure, dynamics, and adaptation of life-history and behavioural traits. However, those factors are often considered independently, and few studies take into account their joint effect. In this study, we investigate the contribution of environment, fishing pressure, and intra-specific competition to variation in the reproductive investment of the Norwegian spring-spawning herring (Clupea harengus), a stock that has been fished for centuries, and monitored for decades. Reproductive investment and post-spawning weight were…
Long-Term Data Reveal the Associations of the Egg Quality With Abiotic Factors and Female Traits in the Baltic Herring Under Variable Environmental C…
2021
In fish, the lipid resources of the female form a link between the environment and progeny, contributing to the contents of the egg yolk. Variation of the environmental conditions is therefore expected to affect the egg quality via maternal pathways, reflecting the female’s response to the environmental factors before spawning. We investigated the content of lipids and thyroid hormones in the ovary and eggs of the Baltic herring during 1988–2019, when salinity of the Baltic Sea first declined and then stabilized to a lower level, and winters varied between severe and mild. The total lipid resources of spawning females decreased by 40–50% during the study, and the ovarian lipid concentration…
Vergleich der prognostischen Aussagefähigkeit der Catterall- und Herring-Klassifikation bei Patienten mit Morbus Perthes
2008
QUESTION Investigation of the predictive value of the Catterall- as compared to the Herring-classification in patients with Perthes disease. METHOD A radiological follow-up study including 53 patients with a total of 59 affected hips was carried out. In the initial diagnosis the Catterall-, Waldenstrom- and Herring-stages were assessed. The epiphyseal ratio, the head-neck ratio and the lateral subluxation were measured and compared at the time of diagnosis, fragmentation stage and in a follow-up examination, which was carried out 4, 9 years after diagnosis on the average. The results of the follow-up examination were assessed using the Mose-classification and compared as well. In addition t…
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.
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…
Changes in crustacean mesozooplankton and some environmental parameters in the Archipelago Sea (Northern Baltic) in 1976-1984
1990
Abstract The abundance of crustacean mesozooplankton was monitored by monthly sampling in the Archipelago Sea (Northern Baltic) during the years 1976-1984. Changes in the abundance of crustacean mesozooplankton species are compared with changes in water temperature, nutrient levels, chlorophyll-a, salinity and population densities of the Baltic herring (Clupea harengus membras L.). There was a rise of water temperature during the study period (about laC on average). The chlorophyll values were increasing, as were the nutrient levels in winter. Salinity was decreasing (on average 0.5‰ S). The biomass and abundance ofplanktivorous Baltic herring were increasing by about 30 and 50 per cent, re…
Swimbladder filling in herring larvae: effects of food oil on the water surface
2020
There has been a recent interest in exploring the possibility of oil and gas production in the Lofoten-Vesterålen area along the Norwegian coast. Since this is an important drift area for offspring of several important commercial fish species, such an activity could potentially have adverse effects on fish early life survival. A potential surface oil spill could coincide in time with swimbladder filling in herring larvae originating from major spawning grounds in Møre, upstream of Lofoten-Vesterålen. A laboratory experiment was carried out to determine possible effects on growth and survival of herring larvae by adding an oil slick to the water surface. The presence of food oil on the water…
High Lipid Content of Prey Fish and n−3 PUFA Peroxidation Impair the Thiamine Status of Feeding-Migrating Atlantic Salmon (Salmo salar) and Is Reflec…
2022
Signs of impaired thiamine (vitamin B1) status in feeding-migrating Atlantic salmon (Salmo salar) were studied in three Baltic Sea areas, which differ in the proportion and nutritional composition of prey fish sprat (Sprattus sprattus) and herring (Clupea harengus). The concentration of n−3 polyunsaturated fatty acids (n−3 PUFAs) increased in salmon with dietary lipids and n−3 PUFAs, and the hepatic peroxidation product malondialdehyde (MDA) concentration increased exponentially with increasing n−3 PUFA and docosahexaenoic acid (DHA, 22:6n−3) concentration, whereas hepatic total thiamine concentration, a sensitive indicator of thiamine status, decreased with th…
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…
Sensitivity of different early developmental periods of Baltic herring (Clupea harengus) to water-accommodated fraction of crude oil
2013
The probability for the oil accident to occur at the Gulf of Finland has been increasing last ten years and it is predicted to continue so. The risk is high based on the accident probability and the probable harm caused; some spawning areas of the Baltic herring (Clupea harengus membras) are located in the vicinity of ports and ship fairways with heavy traffic, so any oil spillage there could affect recruitment of this commercially important species. In this study, newly fertilized embryos, the older embryos and the hatched larvae of Baltic herring were exposed to water-accommodated fraction (WAF) made from crude oil. Oil exposure increased most the mortality of the hatched larvae, and larv…