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  • ICES  (6)
  • Copernicus Publications (EGU)  (2)
  • 1
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    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 8 . pp. 3697-3707.
    Publikationsdatum: 2020-10-16
    Beschreibung: Due to atmospheric accumulation of anthropogenic CO2 the partial pressure of carbon dioxide (pCO2) in surface seawater increases and the pH decreases. This process known as ocean acidification might have severe effects on marine organisms and ecosystems. The present study addresses the effect of ocean acidification on early developmental stages, the most sensitive stages in life history, of the Atlantic herring (Clupea harengus L.). Eggs of the Atlantic herring were fertilized and incubated in artificially acidified seawater (pCO2 1260, 1859, 2626, 2903, 4635 μatm) and a control treatment (pCO2 480 μatm) until the main hatch of herring larvae occurred. The development of the embryos was monitored daily and newly hatched larvae were sampled to analyze their morphometrics, and their condition by measuring the RNA/DNA ratios. Elevated pCO2 neither affected the embryogenesis nor the hatch rate. Furthermore the results showed no linear relationship between pCO2 and total length, dry weight, yolk sac area and otolith area of the newly hatched larvae. For pCO2 and RNA/DNA ratio, however, a significant negative linear relationship was found. The RNA concentration at hatching was reduced at higher pCO2 levels, which could lead to a decreased protein biosynthesis. The results indicate that an increased pCO2 can affect the metabolism of herring embryos negatively. Accordingly, further somatic growth of the larvae could be reduced. This can have consequences for the larval fish, since smaller and slow growing individuals have a lower survival potential due to lower feeding success and increased predation mortality. The regulatory mechanisms necessary to compensate for effects of hypercapnia could therefore lead to lower larval survival. Since the recruitment of fish seems to be determined during the early life stages, future research on the factors influencing these stages are of great importance in fisheries science.
    Materialart: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
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  • 2
    Publikationsdatum: 2017-01-06
    Beschreibung: Herring larvae were sampled during the lllLS in the ICES area IVa from 1990 to 1997. Larval growth was determined based on otolith microstructure analysis from larvae of 7-25mm standard length. The data were correlated to the North Atlantic Oscillation (NAO) and the intlow of Atlantic water (AW) at the same period. The study showed a strong correlation between positive NAO years with a higher inflow of AW and subsequently higher larval growth rates. which could be an indication of favorable growth conditions
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
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    ICES
    In:  [Paper] In: ICES Annual Science Conference 1991, 26.09.1991, La Rochelle, France .
    Publikationsdatum: 2017-01-06
    Beschreibung: The usefulness of multivariate morphometrics to distinguish between fed and starved fish larvae was tested on laboratory reared herring larvae (Clupea harengus ). Linear Discriminant Analysis was used to obtain a linear function which separates the two groups of larvae maximally. The calculations were based on twelve morphometric characters, taken individually by means of an image analysing system. A statistically significant separation of fed and starved larvae was obtained. The most important characters and the number of characters necessary for separation are outlined.
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
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    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 7 . pp. 3915-3919.
    Publikationsdatum: 2020-10-16
    Beschreibung: Ocean acidification, as a consequence of increasing marine pCO2, may have severe effects on the physiology of marine organisms. However, experimental studies remain scarce, in particular concerning fish. While adults will most likely remain relatively unaffected by changes in seawater pH, early life-history stages are potentially more sensitive – particularly the critical stage of fertilization, in which sperm motility plays a central role. In this study, the effects of ocean acidification (decrease of pHT to 7.55) on sperm motility of Baltic cod, Gadus morhua, were assessed. We found no significant effect of decreased pH on sperm speed, rate of change of direction or percent motility for the population of cod analyzed. We predict that future ocean acidification will probably not pose a problem for sperm behavior, and hence fertilization success, of Baltic cod.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Publikationsdatum: 2017-01-06
    Beschreibung: One of the effects of fishing is a reduction in average age and size in exploited fish stocks, leading to an increasing proportion of recruit spawners in the stock. Current management practice assumes equal viability of offspring from first time spawners and from repeat spawners, despite the fact that that first time spawners often produce smaller eggs than older spawners. The aim of this EU-project is to follow offspring from families of first time spawning and older cod, reared under identical and semi-natural conditions in marine enclosures (mesocosms). The parental origin of the larvae is identified using microsatellite DNA methodology. The advantage of this approach, compared to traditional laboratory rearing, is that rearing conditions are close to natural conditions, and all larvae are reared in the same environment. This eliminates the tank-to-tank variability often observed in traditional rearing experiments. The fish are reared from hatching, through the larval and juvenile stages, until sexual maturity. Growth rates, survival and nutritional condition will be measured using methods such as RNA/DNA ratio and otolith micro increment analysis. The results will be related to parental origin and quality measures of the eggs. It is intended to incorporate the results into management models for improvement of fishery management strategies. In this paper we will focus on a description of the project
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
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    ICES
    In:  [Paper] In: ICES Annual Science Conference , 21.09.2011, Gdansk, Poland .
    Publikationsdatum: 2017-01-09
    Beschreibung: Growth rate has been shown to effect survival and recruitment of marine fishes. How growth rates in the field are affected by larval development and environmental variability is poorly understood. Recent growth rates of sprat larvae, a key species in the Baltic Marine ecosystem, were determined by converting RNA/DNA ratios determined from individual larvae into recent growth based on a laboratory calibrated RNA/DNA temperature growth model. Several factors (larval size, temperature and photoperiod) that may contribute to the observed variability in recent growth sampled in the spawning seasons 2002 through 2004 were analyzed with a variety of models. Best fit was found for the Generalized Additive Models (GAMs). Larval size (dry weight), photoperiod and temperature terms explained 29 % and 36 % of the variability observed in recent growth of sprat larvae in the Baltic Sea, respectively.
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
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    ICES
    In:  [Paper] In: ICES Annual Science Conference 1989, 05.10.1989, Den Haag, Netherlands .
    Publikationsdatum: 2017-01-06
    Beschreibung: To estimate the importance of starvation induced mortality for recruitment of marine fish larvae three distinct methods were applied to determine the nutritional condition of fish larvae in situ. In addition to highly sensitive fluorescence techniques for analysing RNA/DNA ratios and tryptic enzyme activities histological standard methods were used to compare the nutritional status of fish larvae of the genus Vinciguerria (Photichthyidae) caught in two ecologically different areas of the Indian Ocean: In the central Arabian Sea and on the continental shelf of Pakistan. A comparison of the results elaborated by the distinct methods shows a trend towards better nutritional conditions for fish larvae from the offshore region.
    Materialart: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
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    ICES | Oxford Univ. Press
    In:  Journal du Conseil / Conseil Permanent International pour l'Exploration de la Mer, 43 . pp. 122-128.
    Publikationsdatum: 2019-08-08
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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