Investigations on 0-group herring

“…The MIK net surveys provide an index of year class strength, but this series has historically had poor spatial resolution in the southern North Sea in the 1990s. The IBTS has been used as an indicator of Downs herring abundance by using the length of herring (Wood 1959, ICES 2009; there are many untested assumptions in this procedure, but it has been generally accepted as suitable. …”

mentioning

confidence: 99%

Variability in transport of fish eggs and larvae. II. Effects of hydrodynamics on the transport of Downs herring larvae

Dickey‐Collas¹,

Bolle²,

Beek³

et al. 2009

Mar. Ecol. Prog. Ser.

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A 10-layered, finite-volume advection-dispersion model with real-time meteorological and freshwater runoff drivers investigated the interannual differences in the transport of Downs herring Clupea harengus L. larvae in the southern North Sea. Simulations were carried out for the winters of 1989 and 1996 to 2003. As they grew, the concentrations of herring larvae developed vertical behaviour. Meteorological forcing transported Downs herring larvae to the nursery grounds in the eastern North Sea with large interannual differences. Diel vertical movement was relatively unimportant in the transport of larvae in the hydrographically mixed southern North Sea. Year classes with less transport of larvae from the hatching area (which was generally warmer) were associated with greater abundances of young Downs herring in the ICES International Bottom Trawl Survey. This implies that retention, rather than dispersal or delivery of larvae to nursery grounds, is associated with the determination of year class strength in Downs herring.KEY WORDS: Clupea harengus · Biophysical models · Downs · Recruitment · Nursery · Drift Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 390: [183][184][185][186][187][188][189][190][191][192][193][194] 2009 1995). Most of the dispersive drift from the spawning grounds of herring stocks in western European waters is in an easterly direction , although other studies have suggested that retention of larvae is important for recruitment success (Iles & Sinclair 1982, Sinclair & Tremblay 1984. On the continental shelf, the local hydrography is highly influenced by meteorological forcing through wind, pressure and runoff, with additional far-field effects (Otto et al. 1990), whilst near the shelf, edge hydrography is also influenced by large-scale basin effects and oceanographic currents (Fernand et al. 2006). Most of the previous studies (e.g. Bartsch et al. 1989, Nichols & Brander 1989 of North Sea herring larval drift were carried out prior to the use of geostrophic (densitydriven) real-time models and thus failed to replicate most of the interannual variability. In addition, they did not account for the influence of freshwater runoff, which is important in the southern North Sea.In the present study we modelled the transport of substances (larvae) as a function of advective and dispersive transport in order to investigate the interannual variability in transport. The larvae were assigned behaviour in the vertical plane, which is different from individual-based modelling approaches or particle tracking of ichthyoplankton , Hinrichsen et al. 2003. We did not model behaviour in the horizontal plane, as this is less important for herring prior to the onset of metamorphosis (Henderson 1987, Gallego & Heath 1994. The sensitivity of the modelled transport to many of the assumptions about diel vertical behaviour was tested, and the final results were compared to empirical data and indices of recruitment in Downs herring. DATA AND METHODSHydrodyna...

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“…Bowers (1964) suggested that the bimodality of the Irish Sea herring is a function of two distinct spawnings in autumn, presumably from the Manx stock and a spring stock of uncertain origin. Different spawnings creating bimodal distributions have also been found in the North Sea (Wood, 1959). Very few fish over one year old were caught, the majority of these in spring before their migration out of the estuary into deeper waters (Parrish & Saville, 1965).…”

Section: Resultsmentioning

confidence: 97%

Disused docks as habitats for estuarine fish: a case study of Preston dock

Conlan

Hendry

White

et al. 1988

Journal of Fish Biology

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A netting and hydrographic study of Preston dock was undertaken between May 1987 and April 1988. Fish populations were assessed using Lundgren monofilament multimesh gillnets. The dock was a low-salinity environment regularly replenished with estuarine water on spring tides. Influxes of higher-salinity water caused intennittent saline wedges in the deeper regions. The dock water was poorly mixed in the summer, resulting in bottom water anoxia. The water was eutrophic, and blue-green algal blooms were common for much of the year.Fourteen freshwater, marine-estuarine, anadromous and catadromous species were present in the dock. No seasonal patterns in diversity were apparent, due to the dominance of the herring population. Changes in species composition and abundance seem to relate to seasonal migratory patterns and, in the case of the freshwater fish, estuarine salinity, rather than to water quality. The suitablity of docks for sampling estuarine fish assemblages is discussed.

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Investigations on 0-group herring

Cited by 8 publications

References 0 publications

Biological and Hydrographic Changes in British Seas During the Last Thirty Years

Biological and Hydrographic Changes in British Seas During the Last Thirty Years

Variability in transport of fish eggs and larvae. II. Effects of hydrodynamics on the transport of Downs herring larvae

Disused docks as habitats for estuarine fish: a case study of Preston dock

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