scholarly journals Feeding habits of harp and hooded seals in Greenland waters

2000 ◽  
Vol 2 ◽  
pp. 50 ◽  
Author(s):  
Finn O Kapel

Results of stomach contents analyses of harp and hooded seals collected in West Greenland waters in the period 1986-1993 are reviewed, and compared with published data and circumstantial information from local hunters. The diet of harp seals in this region is variable but consists mainly of pelagic crustaceans (Thysanoessa spp. and Parathemisto libellula) and small fish species like capelin (Mallotus villosus), sandeel (Ammodytes spp.), polar cod (Boreogadus saida) and Arctic cod (Arctogadus glacialis). Species of importance for commercial fisheries in Greenland, such as Northern prawn (Pandalus borealis), Atlantic cod (Gadus morhua), and Greenland halibut (Reinhardtius hippoglossoides) play a minor role in the diet of harp seals in this area.Variation in the diet of hooded seals is less well documented, but in addition to the species also taken by harp seals, larger demersal fishes like Greenland halibut, redfish (Sebastes spp.), cod, and wolffish (Anarhichas minor) are apparently important prey items.

Author(s):  
Laura Busin Campos ◽  
Xênia Moreira Lopes ◽  
Ednilson da Silva ◽  
Marcos César de Oliveira Santos

AbstractThis study evaluated the feeding habits of the franciscana dolphin (Pontoporia blainvillei) in south-eastern Brazil. Stomach contents were collected from a total of 145 dead specimens found incidentally caught by fishing vessels or stranded between 2005 and 2015. Fish otoliths, cephalopod beaks and whole non-digested prey were used for prey species identification. A total of 9337 prey items were identified, including 26 species of teleost fishes and three species of cephalopods. The most important prey families were Sciaenidae among fish and Loliginidae among cephalopods. Franciscana dolphins tended to feed on small fish (mean = 5.25 cm) and cephalopods (mean = 8.57 cm). The index of relative importance (IRI) showed that Pellona harroweri and Doryteuthis plei were the most important prey for both males and females. The PERMANOVA test confirmed that there is no significant difference between the feeding habits of different sexes, but detected a significant difference among seasons. Overall, our results show that franciscana dolphins are predominantly ichthyophagous and non-selective in relation to the type of prey, feeding on pelagic, demersal and pelagic-demersal prey.


Oecologia ◽  
1996 ◽  
Vol 108 (1) ◽  
pp. 192-196 ◽  
Author(s):  
Elisabeth M. DeBlois ◽  
George A. Rose

2014 ◽  
Vol 43 (3) ◽  
Author(s):  
Ewa Sobecka ◽  
Beata Więcaszek ◽  
Ewa Łuczak ◽  
Artur Antoszek

AbstractThe research was conducted on the parasite fauna and food composition of Eutrigla gurnardus caught as by-catch in commercial catches of the Atlantic cod Gadus morhua near the Shetland Islands. Thirteen species and two genera of pathogens were identified, including six species and one genus recorded for the first time in this host. Copepoda — Euphausiacea dominated in the stomach contents (they are also the intermediate hosts for most of the parasites found), while Gadidae dominated among the fish. A checklist of E. gurnardus parasites is included.


2008 ◽  
Vol 65 (7) ◽  
pp. 1191-1197 ◽  
Author(s):  
A. Bang ◽  
P. Grønkjær ◽  
B. Lorenzen

Abstract Bang, A., Grønkjær, P., and Lorenzen, B. 2008. The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua. – ICES Journal of Marine Science, 65: 1191–1197. Trace metals in the ovaries of fish are transferred from the female via the yolk to the offspring, which makes the early life stages susceptible to deleterious effects of potentially toxic elements contained in the ovaries. Here, the concentrations of 13 elements from the ovaries of 133 ripe female North Sea cod Gadus morhua weighing 0.2–18 kg were correlated with female size, accounting for differences in maturity and condition. Most elements were negatively correlated with the size variables weight, length and, especially, ovarian dry weight. Further, they were negatively correlated with maturity and condition. Many of the trace elements showed true size-dependence, but the correlations were generally weak. A linear discriminant analysis separated “small” and “large” fish at a length of 85 cm based on concentrations of Co, Mn, Se, and Zn, and correctly assigned 78 of 102 small fish and 23 of 31 large fish to their respective size category. This corresponds to an overall classification success of 75.9%. The results suggest that embryos and early larvae from small females are exposed to higher levels of potentially harmful metals. If the differences in trace element concentration influence survival success, this will add to the negative effects of size distribution truncation and declines in size-at-maturity experienced by many populations of cod.


2014 ◽  
Vol 71 (4) ◽  
pp. 784-793 ◽  
Author(s):  
Darrell R. J. Mullowney ◽  
George A. Rose

Abstract The slow recovery of the “northern” Atlantic cod (Gadus morhua) stock off Newfoundland and Labrador has been ascribed to many factors. One hypothesis is poor feeding and condition as a consequence of a decline in capelin (Mallotus villosus), their former main prey. We compared the growth and condition of cod from known inshore (Smith Sound) and offshore (Bonavista Corridor) centres of rebuilding in wild subjects versus captive subjects fed an unlimited diet of oily rich fish. Wild fish in these areas have had different diets and population performance trends since stock declines in the early 1990s. Captive cod from both areas grew at the same rates and achieved equivalent prime condition, while their wild counterparts differed, with smaller sizes, lower condition in small fish, and elevated mortality levels in the offshore centre. Environmental temperature conditions did not account for the differences in performance of wild fish. Our results suggest that fish growth and condition, and hence rebuilding in the formerly large offshore spawning components of the northern cod, have been limited by a lack of capelin in their diet. Furthermore, we suggest that these groups are unlikely to rebuild until a recovery in capelin occurs.


Polar Biology ◽  
2016 ◽  
Vol 39 (6) ◽  
pp. 1137-1153 ◽  
Author(s):  
Kristina Lore Kunz ◽  
Stephan Frickenhaus ◽  
Silvia Hardenberg ◽  
Torild Johansen ◽  
Elettra Leo ◽  
...  

Author(s):  
C.D. MacLeod ◽  
M.B. Santos ◽  
G.J. Pierce

This study reviewed published data on dietary preferences of beaked whales (Ziphiidae) from stomach contents analysis. Detailed data were only available for three of the six beaked whale genera (Hyperoodon, Mesoplodon and Ziphius). Stomach samples of these three beaked whale genera primarily contained cephalopod and fish remains, although some also contained crustaceans. Mesoplodon spp. were found to contain the most fish, with some species containing nothing but fish remains, while the southern bottlenose whale (Hyperoodon planifrons) and Cuvier's beaked whale (Ziphius cavirostris) rarely, if ever, contained fish. Of cephalopods identified, Histioteuthid, Gonatid, Cranchiid and Onychoteuthid species usually contributed most to prey numbers and biomass for all beaked whale genera. There was a wide range of species and families of cephalopods recorded from stomach contents, with no obvious preference for bioluminescent prey species, vertical migrating prey species or prey species with specific body compositions. Whales of the genus Mesoplodon generally contained smaller prey, such as cephalopods under 500 g in weight, compared with other beaked whales. Hyperoodon and Ziphius frequently contained much larger cephalopods with many important prey species having a mean weight of over 1000 g. This suggests that Mesoplodon occupies a separate dietary niche from Hyperoodon and Ziphius, which may be an example of niche segregation. In contrast, Hyperoodon and Ziphius appear to occupy very similar dietary niches but have geographically segregated distributions, with Hyperoodon occupying cold-temperate to polar waters and Ziphius occupying warm-temperate to tropical waters.


Author(s):  
Marco Stagioni ◽  
Stefano Montanini ◽  
Maria Vallisneri

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.


Author(s):  
k.m. norderhaug ◽  
h. christie ◽  
j.h. fosså ◽  
s. fredriksen

predator–prey interactions between fish and macrofauna in kelp (laminaria hyperboea) forest were examined. fish were caught in gill-nets and fish traps at two sites and throughout the diurnal cycle. their stomach contents were analysed. the most abundant fish species, except pollachius virens, were caught in larger numbers at night than during daytime. the examined fish fed throughout the diurnal cycle and kelp-associated fauna were found to be important prey. pollachius virens was caught in the same numbers throughout the diurnal cycle and contained mainly pelagic prey, in larger numbers during the day than at night. small labrids were specialists, feeding mainly on the two numerically dominant kelp-associated gastropods rissoa parva and lacuna vincta. the larger labrus bergylta, gadus morhua and myoxocephalus scorpius were generalists, feeding on a large range of kelp-associated invertebrates. some fish species showed preference for particular vertical levels when feeding in the kelp forest. the most mobile and/or the largest invertebrates were most heavily preyed upon.


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