Stomach contents of bottlenose dolphins (Tursiops truncatus) in Scottish waters

2001 ◽  
Vol 81 (5) ◽  
pp. 873-878 ◽  
Author(s):  
M.B. Santos ◽  
G.J. Pierce ◽  
R.J. Reid ◽  
I.A.P. Patterson ◽  
H.M. Ross ◽  
...  
Keyword(s):  
Salmo Salar ◽  
Tursiops Truncatus ◽  
Gadus Morhua ◽  
Feeding Habits ◽  
Bottlenose Dolphins ◽  
Stomach Contents ◽  
Melanogrammus Aeglefinus ◽  
North East ◽  
Moray Firth ◽  
Merlangius Merlangus

Data on stomach contents of ten bottlenose dolphins (Tursiops truncatus) stranded and by-caught around Scotland (UK) between 1990 and 1999 are presented. Although the species is resident in the Moray Firth (north-east Scotland), little previous information exists on the feeding habits of the species in Scottish waters. Cod (Gadus morhua), saithe (Pollachius virens) and whiting (Merlangius merlangus) were found to be the main prey eaten although several other fish species were also found, including salmon (Salmo salar) and haddock (Melanogrammus aeglefinus), and also cephalopods.

Diet overlap and prey selection through metamorphosis in Irish Sea cod (Gadus morhua), haddock (Melanogrammus aeglefinus), and whiting (Merlangius merlangus)

2008 ◽  
Vol 65 (7) ◽  
pp. 1297-1306 ◽  
Author(s):  
William Ll. Rowlands ◽  
Mark Dickey-Collas ◽  
Audrey J. Geffen ◽  
Richard D.M. Nash
Keyword(s):  
Gadus Morhua ◽  
Prey Selection ◽  
Stomach Contents ◽  
Irish Sea ◽  
Melanogrammus Aeglefinus ◽  
Prey Preferences ◽  
Merlangius Merlangus ◽  
The Irish Sea ◽  
Haddock Melanogrammus Aeglefinus ◽  
Calanus Species

Copepods in the genus Calanus are usually considered to be the preferred prey of gadoid larvae in many areas; however, in the Irish Sea, the abundances of these Calanus species are low and highly variable. We use this situation to test whether Calanus species are still actively selected by gadoid larvae in Calanus -poor environments. Diets of Irish Sea cod ( Gadus morhua ), haddock ( Melanogrammus aeglefinus ), and whiting ( Merlangius merlangus ) were studied from the yolk-sac stage to the juvenile stage. Prey from stomach contents were compared with in situ abundance via an index of prey preference. As expected, all larvae selected copepod nauplii at the onset of feeding. As the larvae developed, their prey preferences changed and varied with species. Cod and whiting showed a similar transition of prey species preference, with a clear preference for Calanus species after metamorphosis, even in this area of low abundance of these Calanus species. The diet composition of haddock differed from that of cod and whiting, as nauplii remained in their diet later into development and there was little preference for individual copepod species detected. The differences in prey selectivity suggested between these gadoids may be attributed to their population variability through the known variability of their preferred prey items.

Seasonal and between-year variations in the diet of harbour seals in the Moray Firth, Scotland

1996 ◽  
Vol 74 (6) ◽  
pp. 1110-1121 ◽  
Author(s):  
D. J. Tollit ◽  
P. M. Thompson
Keyword(s):  
Diet Composition ◽  
Gadus Morhua ◽  
Prey Species ◽  
Temporal Variations ◽  
Short Term ◽  
Harbour Seals ◽  
Faecal Samples ◽  
Poor Indicator ◽  
Moray Firth ◽  
Merlangius Merlangus

Predictions concerning the effect of seals upon prey stocks require an understanding of temporal variations in diet composition. This study examined the extent of between-year and seasonal variations in the diet of harbour seals (Phoca vitulina) from the Moray Firth, Scotland, between 1989 and 1992. Analyses of fish otoliths and cephalopod beaks collected from 1129 faecal samples were used to derive estimates of the contribution made by each of 35 prey species, based on the number and mass consumed. The key prey, by mass, were sand eels (Ammodytidae) (47%), lesser octopus (Eledone cirrhosa) (27%), whiting (Merlangius merlangus) (6%), flounder (Platichthys flesus) (5%), and cod (Gadus morhua) (4%). Between-year and seasonal fluctuations in the contributions of these species were observed. Sand eels contributed 86–20% in summer and 91–49% in winter. Lesser octopus contributed 0–62% in summer and < 5% in winter, whilst whiting and cod contributed 2–34% in winter and 1–4% in summer. In contrast to 1988, clupeids were unimportant in winter. Differences in diet composition appeared to reflect local changes in the availability of food, especially overwintering clupeids. Results indicate that dietary information obtained from short-term studies can be a poor indicator of subsequent diet composition and should be treated with caution when used to predict the effect of seals on prey populations.

scholarly journals The vertical separation of fish in the aft end of a demersal trawl

2009 ◽  
Vol 66 (4) ◽  
pp. 772-777 ◽  
Author(s):  
Ludvig Ahm Krag ◽  
René Holst ◽  
Niels Madsen
Keyword(s):  
Vertical Distribution ◽  
Gadus Morhua ◽  
Melanogrammus Aeglefinus ◽  
Multinomial Model ◽  
Vertical Separation ◽  
Commercially Important ◽  
Merlangius Merlangus ◽  
The Vertical Distribution ◽  
Haddock Melanogrammus Aeglefinus ◽  
Important Fish

Abstract Krag, L. A., Holst, R., and Madsen, N. 2009. The vertical separation of fish in the aft end of a demersal trawl. – ICES Journal of Marine Science, 66: 772–777. Two multi-compartment separator frames were used to study the vertical separation of some commercially important fish species in the aft end of a trawl, with the aim of separating cod (Gadus morhua) from other species. A non-linear multinomial model with random effects was used to analyse the data and to compare the performance of the two frames. The vertical distribution of cod in the aft end of the trawl was close to uniform, whereas haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), and lemon sole (Microstomus kitt) showed more uneven distributions. The use of guiding bars in the separator frame significantly (p < 0.05) increased the catch of cod, plaice, and lemon sole in the upper compartment. The vertical separation of cod was density-dependent; high densities of fish resulted in a more uniform distribution of cod. The species separations found differ from those reported from the studies of species separation in the region of the trawl mouth.

Feeding of tub gurnard Chelidonichthys lucerna (Scorpaeniformes: Triglidae) in the north-east Mediterranean

2011 ◽  
Vol 92 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Marco Stagioni ◽  
Stefano Montanini ◽  
Maria Vallisneri
Keyword(s):  
Diet Composition ◽  
Foraging Behaviour ◽  
Adriatic Sea ◽  
Feeding Habits ◽  
Feeding Activity ◽  
Stomach Contents ◽  
East Mediterranean ◽  
North East ◽  
The North ◽  
Important Prey

The stomach contents of 1096 specimens of Chelidonichthys lucerna were examined in order to analyse their diet composition according to fish size, sex, depth and season. Sampling was carried out from May 2005 to March 2007 during several bottom trawl surveys in the Adriatic Sea (north-east Mediterranean). Feeding activity was more intense in juveniles than in adults. The most important prey was Crustacea (mainly Decapoda: Brachyura, such as Goneplax rhomboides, Liocarcinus spp., Philocheras spp.) and Teleostei (mainly European anchovy Engraulis encrasicolus and black goby Gobius niger). There was no difference between male and female diet. Feeding habits varied with size, with fish dominating the stomach contents of larger specimens. Finally, fish increased in winter and crustaceans in summer. Chelidonichthys lucerna shows a generalist and opportunistic foraging behaviour, preying mainly epibenthic and nectobenthic organisms.

Discarding practices for commercial gadoids in the North Sea

1998 ◽  
Vol 55 (7) ◽  
pp. 1632-1644 ◽  
Author(s):  
Yorgos Stratoudakis ◽  
Robert J Fryer ◽  
Robin M Cook
Keyword(s):  
North Sea ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Melanogrammus Aeglefinus ◽  
The North ◽  
The North Sea ◽  
Merlangius Merlangus ◽  
Using Data ◽  
Species Specific ◽  
Catch Composition

Understanding fishers' discarding behaviour, and anticipating their reactions to changes in the biological or regulatory characteristics of a fishery, are important for dealing with the problem of discarding. In this paper, we investigate the discarding of haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), and Atlantic cod (Gadus morhua) in the North Sea, using data collected by scientific observers onboard Scottish demersal vessels. We describe discarding on each trip by species-specific discard curves and explore how these curves depend on biological and regulatory variables. There are large differences in the size of discarded fish between inshore and offshore areas, with offshore-operating vessels discarding larger fish (high-grading). Increases in legal landing size correspond to immediate increases in the size of discarded fish, particularly for haddock and cod in inshore areas. In general, discarding practices for haddock and cod are similar over time and consistent across gears, whereas decisions for the lesser valued whiting are more variable and can be affected by the catch composition.

scholarly journals Feeding habits of the Robber Frog Pristimantis paulodutrai (Bokermann, 1975) in northeastern Brazil

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Thales Francisco S. S. Alves-dos-Santos ◽  
Lucas Rodriguez Forti ◽  
Marcelo Felgueiras Napoli
Keyword(s):  
Feeding Habits ◽  
Stomach Contents ◽  
Dry Mass ◽  
Northeastern Brazil ◽  
Generalist Predators ◽  
Predator Prey ◽  
North East ◽  
The North ◽  
Generalist Diet ◽  
Ecological Dominance

Abstract: Studying feeding habits is crucial to understand complex predator-prey interactions. Even though anurans play a fundamental role in the control of arthropods populations, the diet of several Neotropical species is poorly known. We describe the frequency and occurrence of prey items and their dry mass in stomach contents of the Robber Frog Pristimantis paulodutrai in the north east of the state of Bahia, Brazil. Based on the stomach contents of 30 individuals, Araneae, Isopoda, and Formicidae were found to be the most important food items. The generalist diet of this frog, which seems to be phylogenetically conserved among Pristimantis, is likely to be linked to its ecological dominance in the habitats surveyed. Our study corroborates the high trophic relevance of Robber Frogs in tropical forests as generalist predators.

Feeding of Atlantic salmon (Salmo salar L.) postsmolts in a fjord in central Norway

1994 ◽  
Vol 72 (5) ◽  
pp. 834-839 ◽  
Author(s):  
C. D. Levings ◽  
N. A. Hvidsten ◽  
B. Ø. Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Larval Fish ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Calanoid Copepods ◽  
Atlantic Salmon Salmo Salar

The feeding habits of postsmolt Atlantic salmon (Salmo salar) caught by two-boat trawling were studied in Trondheimsfjord in central Norway. Fish caught in the inner fjord near the estuaries of the Orkla and Gaula rivers had recently fed on food produced in freshwater and estuarine habitats, namely stonefly and mayfly nymphs and gammarid amphipods. Stomach contents of postsmolts caught farther seaward were dominated by adult insects, with smaller proportions of the food volume originating from marine pelagic (larval fish, hyperiid amphipods, calanoid copepods) and nearshore (gammarid amphipods) habitats.

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