Do protozoa contribute significantly to the diet of larval fish in the Irish Sea?

2007 ◽  
Vol 87 (4) ◽  
pp. 843-850 ◽  
Author(s):  
Gisela M. de Figueiredo ◽  
Richard D.M. Nash ◽  
David J.S. Montagnes
Keyword(s):  
Prey Availability ◽  
Larval Fish ◽  
Food Limitation ◽  
Irish Sea ◽  
Gut Contents ◽  
Fish Feed ◽  
Fish Diet ◽  
Fish Diets ◽  
The Irish Sea ◽  
Taxonomic Groups

This study evaluates the role of protozoa in larval fish feeding by describing protozoa in larval fish diets and testing the hypothesis that, in the Irish Sea, larval fish feed on protozoan prey at rates that potentially sustain their food requirements. Gut contents of 11 taxonomic groups of larval fish were examined, and protist prey occurred in the diet of all of them. Protozoan prey were identified, which provided an insight into their trophic role. Most of the protozoan prey were autotrophic or mixotrophic. In general, larval fish diets were constant over the spring/summer period, regardless of prey availability in the field and the composition of larval fish assemblage (taxonomy and size). A laboratory experiment on ingestion rates of flounder larvae as a function of ciliates concentration was conducted. Combined laboratory and field data showed that, in the Irish Sea, it is unlikely that ciliates are often the primary food source of flounder larvae, and, by implication, other larval fish as well. However, ciliates and other protozoa could be a substantial component of the larval fish diet, and they may potentially prevent food limitation.

The role of the generally unrecognised microprey source as food for larval fish in the Irish Sea

2005 ◽  
Vol 148 (2) ◽  
pp. 395-404 ◽  
Author(s):  
Gisela M. de Figueiredo ◽  
Richard D. M. Nash ◽  
David J. S. Montagnes
Keyword(s):  
Larval Fish ◽  
Irish Sea ◽  
The Irish Sea

The source of bromophenols in some species of Australian ocean fish

1995 ◽  
Vol 31 (11) ◽  
pp. 113-120 ◽  
Author(s):  
F. B. Whitfield ◽  
F. Helidoniotis ◽  
D. Svoronos ◽  
K. J. Shaw ◽  
G. L. Ford
Keyword(s):  
Marine Algae ◽  
Eastern Coast ◽  
Gut Contents ◽  
Fish Diet ◽  
Benthic Organisms ◽  
Important Species ◽  
Relative Contribution ◽  
Fish Diets ◽  
Commercially Important ◽  
Total Concentrations

The carcass and gut contents of 10 species of fish caught along the eastern coast of Australia were analysed by gas chromatography-multiple ion detection-mass spectrometry for a range of bromophenols including 2- and 4-bromophenol, 2,4- and 2,6-dibromophenol and 2,4,6-tribromophenol. These bromophenols, the cause of iodoform-like off-flavours in seafoods, were found in eight of the above species; the largest total concentrations of bromophenols occurred in the commercially important species Nemadactylus douglasii (40 ng/g). The concentrations of bromophenols in another three species Branchiostegus wardi, Rhabdosargus sarba, and Girella tricuspidata, were found to exceed 10 ng/g while in a further four species their concentrations varied between 3 and 8 ng/g. However, these compounds were not identified in the remaining two species at a detection limit of 0.05 ng/g. The variations among fish diets suggest that the bromophenol content of individual fish can be explained by the relative contribution of benthic organisms and marine algae to the fish diet. Bromophenols were found in all of the benthic carnivores and diverse omnivores examined but were not detected in pelagic carnivorous fish.

scholarly journals Effects of bottom trawling on fish foraging and feeding

2015 ◽  
Vol 282 (1799) ◽  
pp. 20142336 ◽  
Author(s):  
Andrew Frederick Johnson ◽  
Giulia Gorelli ◽  
Stuart Rees Jenkins ◽  
Jan Geert Hiddink ◽  
Hilmar Hinz
Keyword(s):  
Body Condition ◽  
Prey Availability ◽  
Management Strategies ◽  
Mitigation Measures ◽  
Irish Sea ◽  
Foraging Efficiency ◽  
Bottom Trawling ◽  
Prey Biomass ◽  
Reduced Body ◽  
The Irish Sea

The effects of bottom trawling on benthic invertebrates include reductions of biomass, diversity and body size. These changes may negatively affect prey availability for demersal fishes, potentially leading to reduced food intake, body condition and yield of fishes in chronically trawled areas. Here, the effect of trawling on the prey availability and diet of two commercially important flatfish species, plaice ( Pleuronectes platessa ) and dab ( Limanda limanda ), was investigated over a trawling intensity gradient in the Irish Sea. Previous work in this area has shown that trawling negatively affects the condition of plaice but not of dab. This study showed that reductions in local prey availability did not result in reduced feeding of fish. As trawling frequency increased, both fish and prey biomass declined, such that the ratio of fish to prey remained unchanged. Consequently, even at frequently trawled sites with low prey biomass, both plaice and dab maintained constant levels of stomach fullness and gut energy contents. However, dietary shifts in plaice towards energy-poor prey items were evident when prey species were analysed individually. This, together with a potential decrease in foraging efficiency due to low prey densities, was seen as the most plausible cause for the reduced body condition observed. Understanding the relationship between trawling, benthic impacts, fish foraging and resultant body condition is an important step in designing successful mitigation measures for future management strategies in bottom trawl fisheries.

The medieval cultures of the Irish sea and the North Sea: Manannan and his neighbors [Book Review]

2019 ◽  
Vol 15 ◽  
pp. 142-144
Author(s):  
John Kennedy
Keyword(s):  
North Sea ◽  
Irish Sea ◽  
The North ◽  
The North Sea ◽  
The Irish Sea

Review(s) of: The medieval cultures of the Irish sea and the North Sea: Manannan and his neighbors, by MacQuarrie, Charles W., and Nagy, Joseph Falaky Nagy (eds), (Amsterdam: Amsterdam University Press, 2019) hardcover, 212 pages, 1 map, 4 figures, RRP euro99; ISBN 9789462989399.

scholarly journals Morphological abnormality in thornback ray Raja clavata in the Irish Sea

2021 ◽  
Author(s):  
L. J. Clarke
Keyword(s):  
Irish Sea ◽  
Beam Trawl ◽  
Morphological Abnormality ◽  
Free Swimming ◽  
Pectoral Fins ◽  
North Wales ◽  
Head Section ◽  
Thornback Ray ◽  
Raja Clavata ◽  
The Irish Sea

AbstractA free-swimming thornback ray Raja clavata specimen demonstrating significant morphological abnormality is reported, captured by beam trawl in the Irish Sea off north Wales, UK. The anterior sections of both pectoral fins were separated from the head section for a length of approximately 140 mm extending from the rostrum tip to a point posterior of the spiracles, along with abnormal morphology of the gill slits. This phenomenon has been observed elsewhere but is the first documented example of this abnormality in the eastern Irish Sea, despite widespread targeting of the species across the region by commercial and recreational fishers. Possible causes and consequences of the observed abnormality are discussed.

A detailed comparison of measured and modeled wind-driven currents in the North Channel of the Irish Sea

2001 ◽  
Vol 106 (C9) ◽  
pp. 19683-19713 ◽  
Author(s):  
Alan M. Davies ◽  
Philip Hall ◽  
M. John Howarth ◽  
Philip Knight ◽  
Rose Player
Keyword(s):  
Detailed Comparison ◽  
Irish Sea ◽  
The North ◽  
The Irish Sea ◽  
Wind Driven Currents

scholarly journals Temporal trends in stock origin and abundance of juvenile herring (Clupea harengus) in the Irish Sea

2009 ◽  
Vol 66 (8) ◽  
pp. 1749-1753 ◽  
Author(s):  
Nóirín Burke ◽  
Deirdre Brophy ◽  
Pieter-Jan Schön ◽  
Pauline A. King
Keyword(s):  
Temporal Trends ◽  
Clupea Harengus ◽  
Irish Sea ◽  
First Year ◽  
Juvenile Abundance ◽  
Abundance Estimates ◽  
Otolith Microstructure Analysis ◽  
Celtic Sea ◽  
The Irish Sea ◽  
First Year Of Life

Abstract Burke, N., Brophy, D., Schön, P-J., and King, P. A. 2009. Temporal trends in stock origin and abundance of juvenile herring (Clupea harengus) in the Irish Sea. – ICES Journal of Marine Science, 66: 1749–1753. Celtic Sea herring (Clupea harengus) larvae partly disperse into the Irish Sea, where they mix with the resident stock during their first year of life. This affects the reliability of the use of acoustic estimates of juvenile abundance on the Irish Sea nursery grounds as a recruitment index for use in stock predictions. Otolith microstructure analysis can be used to distinguish between autumn-spawned and winter-spawned individuals. Because winter spawners do not occur in the Irish Sea, this component can be assigned to Celtic Sea immigrants. We used this method to estimate the proportion of winter-spawned individuals in samples of age-1 herring from the western Irish Sea over a 10-year period (1993–2003), and subtracted a corresponding proportion from the acoustic age-1 abundance estimates. The adjusted index for autumn-spawned (supposedly Irish Sea) juveniles was significantly correlated with the abundance of age-3 fish from the same year class in commercial catches and in the acoustic surveys (p < 0.05 and <0.01, respectively), whereas the correlations for unadjusted indices were not significant. These findings are discussed in relation to the monitoring and assessment of herring in the two areas.

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