scholarly journals A note on stomach contents of minke whales (Balaenoptera acutorostrata) in Icelandic waters

2000 ◽  
Vol 2 ◽  
pp. 82 ◽  
Author(s):  
Jóhann Sigurjónsson ◽  
Anton Galan ◽  
Gísli A Víkingsson
Keyword(s):  
Food Habits ◽  
Gadus Morhua ◽  
Prey Species ◽  
Stomach Contents ◽  
Clupea Harengus ◽  
Balaenoptera Acutorostrata ◽  
Minke Whales ◽  
Capelin Mallotus Villosus ◽  
Available Information ◽  
Icelandic Waters

There is limited available information on food habits of minke whales (Balaenoptera acutorostrata) in coastal Iceland. Sixty-eight minke whales were examined for stomach contents; 51.5% contained fish only, 22.1 % krill (Euphausiacea) only, 25.0% fish and krill together, and one animal (l.5%) had no food remains in the stomach. The fish species identified were capelin (Mallotus villosus), sandeel (Ammodytidae), cod (Gadus morhua) and herring (Clupea harengus). Two species of krill were identified; Thysanoessa raschii and Meganyctiphanes norvegica. Sandeel was the dominant prey species in the western and southwestern areas, while capelin and krill were more frequently found in animals sampled in North Iceland.

scholarly journals In vitrodigestibility of different prey species of minke whales (Balaenoptera acutorostrata)

1993 ◽  
Vol 70 (2) ◽  
pp. 485-489 ◽  
Author(s):  
Erling S. Nordøy ◽  
Wenche Sørmo ◽  
Arnoldus Schytte Blix
Keyword(s):  
Gadus Morhua ◽  
Prey Species ◽  
Initial Step ◽  
Common Species ◽  
Clupea Harengus ◽  
Melanogrammus Aeglefinus ◽  
Balaenoptera Acutorostrata ◽  
Minke Whales ◽  
Digestion Technique

Information on diet composition, daily energy expenditure, energy storage and the utilization of energy in the prey are important factors when evaluating the food consumption of minke whales (Balaenoptera acutorostrata) during their summer stay in northern waters. The purpose of the present study was in this context to obtain information on the digestible energy (DE) of different prey selected by minke whales. Anin vitrothree-stage digestion technique, simulating the different compartments of the digestive system, has been developed. The initial step simulated the anaerobic microbial fermentation of substrate in the fortestomach. The next stage included the addition of pepsin (EC3.4.23.1)–HCI, simulating ventricle enzymic decomposition, and finally, in the third step, fresh extract from duodenal contents was used to simulate enzymic intestinal degradation of the remaining components of the food. The inoculum was normally obtained from animals which had recently eaten the prey to be tested. In such tests we obtained a dry matter disappearance (DMD) and a DE for herring (Clupea harengus) of 80·4 (SD 5·0)% (n18) and 92·1 (SD 3·7) % (n16) respectively, and a DMD of krill (Thysanoessasp.) of 83·4 (SD 4·9)% (n6). The DMD of krill was reduced to 73·8 (SD 7·3)% (n8) while the DE was 70·6 (SD 10·4) % (n7) when inoculum from whales which had recently eaten cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) was used. These results indicate a high digestibility of the most common species of prey in these animals, and also that the whales have little difficulty in changing from one prey species to another.

scholarly journals Direct and indirect effects of minke whale abundance on cod and herring fisheries: A scenario experiment for the Greater Barents Sea

2000 ◽  
Vol 2 ◽  
pp. 120 ◽  
Author(s):  
Tore Schweder ◽  
Gro S Hagen ◽  
Einar Hatlebakk
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Minke Whale ◽  
Clupea Harengus ◽  
Prey Abundance ◽  
Balaenoptera Acutorostrata ◽  
Time Step ◽  
Minke Whales ◽  
Spawning Stock ◽  
Capelin Mallotus Villosus

To study the pattern of interaction between minke whale (Balaenoptera acutorostrata) abundance and the main fisheries in the Greater Barents Sea, a simulation experiment was carried out. The population model involves 4 species interconnected in a food web: cod (Gadus morhua), capelin (Mallotus villosus), herring (Clupea harengus) and minke whales. Minke whales are preying on cod, capelin andherring; cod are preying on (young) cod, capelin and herring; herring in the Barents Sea are preying on capelin; while capelin is a bottom prey in the model. The consumption function for minke whales is non-linear in available prey abundance, and is estimated from stomach content data and prey abundance data. The model is dynamic, with a time step of one month, and there are two areas: the BarentsSea and the Norwegian Sea. Minke whale abundances are kept on fixed levels, while recruitment in fish is stochastic.Cod and herring fisheries are managed by quotas targeting fixed fishing mortalities, while capelin is managed with a view to allow the cod to have enough food and leaving a sufficient spawning stock of capelin. The model is simulated over a period of 100 years for a number of fixed levels of minke whaleabundance, and simulated catches of cod, herring and capelin are recorded.The experiment showed interactions between whale abundance and fish catches to be mainly linear. For cod catches, both the direct effect of whales consuming cod, and the indirect effect due to whales competing with cod for food and otherwise altering the ecosystem, are linear and of equal importance. The net effect on the herring fishery is of the same magnitude as the net effect on the cod fishery, witheach extra whale reducing the catches of both species by some 5 tonnes. These conclusions are conditional on the model and its parameterisation.

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

2004 ◽  
Vol 84 (6) ◽  
pp. 1241-1244 ◽  
Author(s):  
G.J. Pierce ◽  
M.B. Santos ◽  
R.J. Reid ◽  
I.A.P. Patterson ◽  
H.M. Ross
Keyword(s):  
North Sea ◽  
Stomach Contents ◽  
Clupea Harengus ◽  
Balaenoptera Acutorostrata ◽  
Sprattus Sprattus ◽  
The North ◽  
Minke Whales ◽  
The North Sea

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.

scholarly journals The diet of the minke whale in Greenland - A short review

2000 ◽  
Vol 2 ◽  
pp. 92 ◽  
Author(s):  
Pia Barner Neve
Keyword(s):  
Prey Item ◽  
Stomach Contents ◽  
Short Review ◽  
Coastal Areas ◽  
Minke Whale ◽  
Balaenoptera Acutorostrata ◽  
Mallotus Villosus ◽  
Minke Whales ◽  
Capelin Mallotus Villosus

Information on the diet of minke whales (Balaenoptera acutorostrata) in Greenland waters is reviewed. The knowledge is based on reports by whale catchers in Greenland, supplemented by limited scientific studies of stomach contents. The available material indicates that capelin (Mallotus villosus) is the predominant prey item in Greenland waters, particularly in coastal areas. In offshore areas, sand eel (Ammodytes spp) is consumed rather frequently, and krill (euphausids) appears to play a certain role in some areas or periods.

Diet of harp seals (Phoca groenlandica) in nearshore waters of the northwest Atlantic during 1990 – 1993

1995 ◽  
Vol 73 (10) ◽  
pp. 1805-1818 ◽  
Author(s):  
John W. Lawson ◽  
Garry B. Stenson ◽  
Dave G. McKinnon
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stomach Contents ◽  
Clupea Harengus ◽  
Relative Importance ◽  
Northwest Atlantic ◽  
Arctic Cod ◽  
Diet Diversity ◽  
Phoca Groenlandica ◽  
Capelin Mallotus Villosus

The nearshore diet of northwest Atlantic harp seals (Phoca groenlandica) was determined by reconstructing the contents of 1167 prey-containing stomachs (78.3% of 1490) collected from 1990 to 1993. Although harp seals consumed at least 62 species, 6 accounted for most of the mass consumed and their relative importance varied by area. Based on percent wet mass, sculpins (Cottidae) and Arctic cod (Boreogadus saida) were the main components of the diet of older seals (> 1 year old) off Labrador, whereas Arctic cod and Atlantic herring (Clupea harengus) were the main prey of seals from northeastern Newfoundland. A more diverse diet was observed in seals taken off the west coast of Newfoundland, where capelin (Mallotus villosus), herring, Atlantic cod (Gadus morhua), redfish (Sebastes spp.), and Arctic cod were the main species. Redfish and Atlantic cod were important to seals along the south coast of Newfoundland. Eighty percent of fish consumed were less than 18 cm long, smaller than those taken by commercial fisheries. Pups (less than 1 year old) consumed fewer and smaller prey of a less varied assortment. Annual and seasonal variation in the diets was observed in the collection from northeastern Newfoundland. Arctic cod was the major prey consumed throughout the year by seals of all ages, although the relative importance of herring, capelin, and squid (Teuthoidea) increased during the summer. Invertebrates and capelin made up a greater proportion of the diet in 1992, owing to a decline in consumption of Arctic cod. This finding was associated with a decrease in the mass of stomach contents. Diet diversity did not change significantly over the study period.

Stomach contents of harbour porpoises, Phocoena phocoena (L.), from the Bay of Fundy

1989 ◽  
Vol 67 (9) ◽  
pp. 2140-2146 ◽  
Author(s):  
Cheri A. Recchia ◽  
Andrew J. Read
Keyword(s):  
Gadus Morhua ◽  
Prey Species ◽  
Atlantic Cod ◽  
Caloric Intake ◽  
Stomach Contents ◽  
Clupea Harengus ◽  
Spatial And Temporal Variation ◽  
Bay Of Fundy ◽  
Phocoena Phocoena ◽  
Total Caloric Intake

We examined contents from stomachs of 127 harbour porpoises (Phocoena phocoena) caught in groundfish gill nets in the western Bay of Fundy during June to September, 1985–1987. Relative importance of prey species was assessed using both numerical and caloric measures. Atlantic herring (Clupea harengus) was the most important prey species, contributing 80% of the total caloric intake, with some spatial and temporal variation. Silver hake (Merluccius bilinearis) and Atlantic cod (Gadus morhua) were also important, but together comprised only 17% of the total caloric intake. No differences were found in relative prey importance between adult porpoises of different reproductive conditions, but lactating females ingested more fish and had a significantly higher total caloric intake than nonlactating females or mature males. The diet of porpoises collected from the same area in 1969–1972 consisted of a higher proportion of pelagic prey species and a lower proportion of demersal species. This may be attributed to differences in capture method, as the earlier sample of porpoises was collected at the surface, while the present animals were captured at depths of 45–100 m.

Comparison of harbour seal diets in two inshore habitats of Atlantic Canada

1996 ◽  
Vol 74 (1) ◽  
pp. 125-135 ◽  
Author(s):  
W. D. Bowen ◽  
G. D. Harrison
Keyword(s):  
Gadus Morhua ◽  
Prey Species ◽  
Atlantic Cod ◽  
Atlantic Coast ◽  
Clupea Harengus ◽  
Harbour Seal ◽  
Bay Of Fundy ◽  
Alosa Pseudoharengus ◽  
Pseudopleuronectes Americanus ◽  
Capelin Mallotus Villosus

We studied the composition of harbour seal (Phoca vitulina) diets in two areas, the lower Bay of Fundy and along the northeastern coast of Nova Scotia, that differ in prey species diversity, bottom type, and physical oceanography. Prey remains were found in 250 of 470 harbour seal stomachs collected mainly from May to September between 1988 and 1992. Although 23 taxa were identified, four species, Atlantic herring (Clupea harengus), Atlantic cod (Gadus morhua), pollock (Pollachius virens), and short-finned squid (Illex illecebrosus), accounted for 84% of the estimated biomass of prey consumed in the two areas combined. Species, such as herring and squid, that dominated the diets in both habitats, also tended to be abundant in both habitats during the summer. Atlantic cod was the principal gadoid in the Bay of Fundy, whereas pollock was most important along the Atlantic coast. Differences in prey distribution and abundance appeared to account for differences in the contribution of the alewife (Alosa pseudoharengus), winter flounder (Pseudopleuronectes americanus), hake (Urophycis spp.), and capelin (Mallotus villosus) in the diet. Pronounced interannual variation in the species composition of diets was evident in both habitats. This variation was associated with broad-scale changes in prey abundance in some cases (e.g., squid and capelin) but not in others (e.g., Atlantic cod and pollock).

scholarly journals Estimated food consumption of minke whales Balaenoptera acutorostrata in Northeast Atlantic waters in 1992-1995

2000 ◽  
Vol 2 ◽  
pp. 65 ◽  
Author(s):  
Lars P Folkow ◽  
Tore Haug ◽  
Kjell T Nilssen ◽  
Erling S Nordøy
Keyword(s):  
Barents Sea ◽  
Regional Distribution ◽  
Clupea Harengus ◽  
Mortality Factor ◽  
Point Estimate ◽  
Melanogrammus Aeglefinus ◽  
Balaenoptera Acutorostrata ◽  
Northeast Atlantic ◽  
Minke Whales ◽  
Prey Items

Data on energy requirements, diet composition, and stock size were combined to estimate the consumption of various prey species by minke whales (Balaenoptera acutorostrata) in Northeast Atlantic waters. In the period 1992-1995, the stock of 85,000 minke whales appeared to have consumed more than 1.8 million tonnes of prey per year in coastal waters off northern Norway, in the Barents Sea and around Spitsbergen during an assumed 6 month stay between mid-April and mid-October.Uncertainties in stock estimates suggest a 95% confidence range of 1.4 - 2.1 million tonnes. The point estimate was composed of 602,000 tonnes of krill Thysanoessa spp., 633,000 tonnes of herring Clupea harengus, 142,000 tonnes of capelin Mallotus villosus, 256,000 tonnes of cod Gadus morhua, 128,000 tonnes of haddock Melanogrammus aeglefinus and 54,500 tonnes of other fish species, including saithe Pollaehius virens and sand eel Ammodytes sp. Consumption of various prey items by minke whales may represent an important mortality factor for some of the species. For example, the estimated annual consumption of herring corresponds to about 70% of the herring fisheries in the Northeast Atlantic in 1995. Minke whale diets are subject to year-to-year variations due to changes in the resource base in different feeding areas. Thus, the regional distribution of consumption of different prey items is highly dynamic.

scholarly journals Marine mammals' influence on ecosystem processes affecting fisheries in the Barents Sea is trivial

2009 ◽  
Vol 5 (2) ◽  
pp. 204-206 ◽  
Author(s):  
Peter J Corkeron
Keyword(s):  
Marine Mammal ◽  
Marine Mammals ◽  
Gadus Morhua ◽  
Fishery Management ◽  
Barents Sea ◽  
Scientific Evidence ◽  
Primary Component ◽  
Clupea Harengus ◽  
Balaenoptera Acutorostrata ◽  
The Barents Sea

Some interpretations of ecosystem-based fishery management include culling marine mammals as an integral component. The current Norwegian policy on marine mammal management is one example. Scientific support for this policy includes the Scenario Barents Sea (SBS) models. These modelled interactions between cod, Gadus morhua , herring, Clupea harengus , capelin, Mallotus villosus and northern minke whales, Balaenoptera acutorostrata . Adding harp seals Phoca groenlandica into this top-down modelling approach resulted in unrealistic model outputs. Another set of models of the Barents Sea fish–fisheries system focused on interactions within and between the three fish populations, fisheries and climate. These model key processes of the system successfully. Continuing calls to support the SBS models despite their failure suggest a belief that marine mammal predation must be a problem for fisheries. The best available scientific evidence provides no justification for marine mammal culls as a primary component of an ecosystem-based approach to managing the fisheries of the Barents Sea.

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