Diet of minke whales Balaenoptera acutorostrata in Scottish (UK) waters with notes on strandings of this species in Scotland 1992–2002

Author(s):  
G.J. Pierce ◽  
M.B. Santos ◽  
R.J. Reid ◽  
I.A.P. Patterson ◽  
H.M. Ross

During 1992–2002 approximately 110 strandings of minke whales Balaenoptera acutorostrata were recorded in Scotland (UK). Most strandings were recorded between April and November, with a peak of strandings of males in July and August. There were two length modes at 4–6 m and 7–10 m. Stomach contents samples were obtained from ten animals. The diet comprised mainly sandeels (Ammodytidae, around two-thirds of the diet by number or weight) and clupeids (herring Clupea harengus and sprat Sprattus sprattus). Results on diet are consistent with results from whaling catches in the North Sea. The possibility that minke whales compete with fisheries is discussed.

Polar Biology ◽  
2002 ◽  
Vol 25 (12) ◽  
pp. 907-913 ◽  
Author(s):  
Erik W. Born ◽  
Henning Dahlgaard ◽  
Frank F. Riget ◽  
Rune Dietz ◽  
Nils Øien ◽  
...  

2019 ◽  
Vol 20 (3) ◽  
pp. 537-551 ◽  
Author(s):  
Juan Estrella‐Martínez ◽  
Bernd R. Schöne ◽  
Ruth H. Thurstan ◽  
Elisa Capuzzo ◽  
James D. Scourse ◽  
...  

Author(s):  
Lindsay R. McPherson ◽  
Konstantinos Ganias ◽  
C. Tara Marshall

Macroscopic maturity staging data are widely used to distinguish between reproductive and non-reproductive individuals. The implicit assumption is that these data are accurate. The accuracy of macroscopic maturity staging of North Sea herring (Clupea harengus) has not been checked since the macroscopic scale was produced in 1961. The aim of this study was to assess the accuracy of macroscopic maturity staging of female North Sea herring by comparison to histological staging and the gonadosomatic index (GSI). Ovary samples were collected during the North Sea Herring Acoustic Survey in 2006 on-board FRV ‘Scotia’ (Scotland) and in 2007 on-board FRV ‘Scotia’ and RV ‘Johan Hjort’ (Norway). Commercial samples were also collected by Marine Scotland, Aberdeen in both years. The maturity staging error was relatively low in 2006 (21% error) but was much higher on-board FRV ‘Scotia’ (57%) and RV ‘Johan Hjort’ (47%) in 2007. There was estimated to be a 27% under-estimation of the spawning stock biomass (SSB) in 2007 due to the differences in the proportion mature but no change in SSB estimates in 2006. GSI cut-off scores, estimated by means of multinomial regression models were successfully able to separate immature females from both mature-active and recovering females; however, there was some overlap between the mature-active and recovering individuals. We conclude that an effective and low-cost means of reducing error in herring maturity studies is the combined use of a four-point macroscopic maturity scale with routinely collected GSI data, the latter acting to validate and fine tune macroscopic staging.


2000 ◽  
Vol 57 (12) ◽  
pp. 2363-2367 ◽  
Author(s):  
Sara A Adlerstein ◽  
Henny C Welleman

Results show that the weight of cod (Gadus morhua) stomach contents sampled in the North Sea varies significantly within 24 h. To determine whether feeding varied with time, over 1100 cod stomachs were collected around the clock between 7 and 18 May 1984 in two areas in the central North Sea thought to be representative for feeding studies. Here we investigate temporal feeding patterns based on the analysis of stomach-content data, using generalized additive models (GAMs). Results show significant variation of content weight and indicate morning and evening peaks. The relative peak importance differed between and within areas. We propose that differences are due to diet composition, namely, prey size and diel availability. Cod fed primarily on molluscs, mainly ocean quahog (Cyprina islandica), crustaceans, sandeels (Ammodytes spp.), haddock (Melanogrammus aeglefinus), herring (Clupea harrengus), and several flatfish species. In one area, the diet was dominated by fish, relatively large prey that perform diel vertical migration, and in the other by invertebrates, smaller prey that are digested faster. The diel pattern was more pronounced where invertebrate prey were dominant. Generalisation of results and implications for predation-mortality estimates based on data from the North Sea Stomach Content Database, used to implement multispecies models in the region, are discussed.


1991 ◽  
Vol 11 (12) ◽  
pp. 1425-1452 ◽  
Author(s):  
M. Heath ◽  
K. Brander ◽  
P. Munk ◽  
P. Rankine

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