Recent changes in the winter diet of murres (Uria spp.) in coastal Newfoundland waters

2000 ◽  
Vol 78 (3) ◽  
pp. 495-500 ◽  
Author(s):  
Sherrylynn Rowe ◽  
Ian L Jones ◽  
John W Chardine ◽  
Richard D Elliot ◽  
Brian G Veitch

We investigated the winter diet of murres (Uria spp.) in coastal Newfoundland waters in relation to environmental and ecological changes that have occurred in the Northwest Atlantic since the 1980s. We analyzed the contents of 371 stomachs (311 from Thick-billed Murres, Uria lomvia, and 60 from Common Murres, Uria aalge) of birds shot by hunters around the Newfoundland coast during the winters of 1996-1998. We observed that the frequency of empty stomachs was greater in our study than in a similar study conducted during 1984-1986. We found no difference in the proportion of fish in the diet between the 1980s and the 1990s, however, Arctic cod (Boreogadus saida; from 55 to 12%) and capelin (Mallotus villosus; from 28 to 6%) decreased in frequency of occurrence. The proportion of stomachs containing crustaceans and squid did not change between the 1980s and 1990s, but hyperiid amphipods (Parathemisto spp.) replaced euphausiids (Thysanoessa spp.) as the predominant crustacean. Changes in murre winter diet off the coast of Newfoundland corroborate other sources of information indicating that major changes in the distribution and biology of marine organisms occurred in the Northwest Atlantic during the 1990s.

1987 ◽  
Vol 65 (7) ◽  
pp. 1638-1649 ◽  
Author(s):  
T. R. Birkhead ◽  
D. N. Nettleship

A simultaneous comparison of the foods of Common Murre, Uria aalge, and Thick-billed Murre, Uria lomvia, chicks at the same location showed that the species composition of fish fed to chicks of the two murre species differed significantly. In both years of the study, Common Murre chicks were fed predominantly capelin, Mallotus villosus (78–80% by weight), whereas Thick-billed Murre chicks were fed mainly daubed shanny, Lumpenus maculatus (61–70% by weight). Thick-billed Murres tended to feed their chicks more frequently than Common Murres, probably because in both years the mean caloric value of their prey was lower than that of the Common Murre's. No other statistically significant interspecific differences were consistent between years. Prey lengths and weights overlapped considerably between the murre species, and the caloric intake of chicks showed no consistent interspecific difference. Marked interyear differences in feeding rate, prey size, and caloric intake occurred in both species. In 1982 ice breakup was late, and the murres' breeding seasons were delayed; this appeared to result in poor synchronization between the temporal pattern of food availability and the timing of each species' chick-rearing period, and the caloric intakes of chicks of both species were lower in that year than in 1983.


1993 ◽  
Vol 71 (2) ◽  
pp. 264-272 ◽  
Author(s):  
Knud Falk ◽  
Jan Durinck

The diet of thick-billed murres (Uria lomvia) wintering in coastal western Greenland was studied by analyzing the stomach contents of 202 birds supplied by local hunters in four regions, from October 1988 to March 1989. Fish and crustaceans were present in 68 and 71% (frequency of occurrence), respectively, of all stomachs containing prey remains (n = 195). Fish made up 81% wet weight, and crustaceans most of the remaining 19%, except for < 1% squid (Gonatus sp.) and polychaetes (Nereis sp.). Capelin (Mallotus villosus) was the dominant prey species (61% wet weight), followed by Thysanoessa spp. (17%), Parathemisto spp. (1%), and Meganyctiphanes norvegica (1%). Euphausiids were the most abundant crustaceans (95% wet weight of all crustaceans), except in October, when hyperid amphipods were dominant (89%). Crustaceans were important in the murres' diet only in the northern part of the survey area; birds in the southern part preyed almost exclusively upon capelin. Most birds were in good body condition (based on the amount of body fat), but murres from the southern area had a slightly higher mean fat index than those from the northern area (7.19 vs. 5.35). We suggest that differences in body condition may be related to the higher proportion of fish, which is of higher caloric value, in the diet of murres in the southern area.


Author(s):  
Flemming Ravn Merkel ◽  
Jannie Fries Linnebjerg ◽  
Ole Norden Andersen ◽  
Nicholas Per Huffeldt ◽  
Teunis Jansen ◽  
...  

Southwest Greenland constitutes an internationally important wintering area for seabirds, including thick-billed murres (Uria lomvia Linnaeus, 1758), but their prey may be affected by the general warming of this sub-Arctic region. We compare murre diet collected in winter in the 1990s and 2010s around Nuuk. Fish made up 36% of the diet (wet mass) and crustaceans 63% in the 1990s, changing to 22% and 78% in the 2010s, respectively. Capelin (Mallotus villosus Müller, 1776) was the dominant fish species, and the smaller contribution in the 2010s coincided with declining densities of capelin around Nuuk. The crustaceans were dominated by two krill species, Meganyctiphanes norvegica M. Sars, 1857, and Thysanoessa inermis Krøyer, 1846. However, M. norvegica was only important in the 2010s (51% wet mass), while T. inermis was dominating the 1990s with 62% wet mass and only 23% in 2010s. The dominance of M. norvegica in the 2010s confirmed our expectations of a gradual “borealization” of this region due to the generally warming sub-Arctic. The smaller contribution of fish in the diet may also support the hypothesis of deteriorating winter conditions for murres. Apart from the diet, plastic was found in 15% of the birds and 53% had parasitic nematods.


1999 ◽  
Vol 77 (8) ◽  
pp. 1278-1287 ◽  
Author(s):  
Rachel Bryant ◽  
Ian L Jones ◽  
J Mark Hipfner

We quantified Common Murre (Uria aalge) and Thick-billed (Uria lomvia) Murre chick diets, chick-feeding rates, breeding success, chick growth, adult masses, and pair members' time spent together at site at the Gannet Islands, Labrador, in 1996 and 1997, after a decline in capelin (Mallotus villosus) abundance along the coast of southern and central Labrador. These results, with the exception of time spent at the site, were compared with those collected by other researchers at the Gannet Islands in 1981-1983, before the capelin decline. The two species responded similarly to the decline. After the decline, murres fed their chicks up to 75% fewer capelin and up to 65% more daubed shannies (Lumpenus maculatus). Feeding rates of both murre species varied among years, without respect to changes in the proportion of capelin. We found no evidence for declines in colony attendance, breeding success, chick growth, and adult mass. No data on time spent at the site were available before the decline in capelin abundance, but after the decline, off-duty murres of both species spent a mean of 10 min at their sites per feeding visit. This amount of time was short with respect to that recorded for Common Murres elsewhere, suggesting that murres' foraging effort at the Gannet Islands was high and buffered the effects of prey availability on other parameters measured. Taken together, our results suggest that murres responded to changing capelin abundance by changing their chicks' diet, but were otherwise little affected.


Author(s):  
S.R. Flynn ◽  
B.S. Nakashima ◽  
M.P.M. Burton

Assessment of spawning survival for female capelin Mallotus villosus (Pisces: Osmeriformes) greater than 12 cm in length was made in the autumn of 1995–1997 comparing a histological technique with existing methods. An intensive macroscopic visual assessment of selected samples from 1995, 1996 and 1997 revealed that 10, 20 and 40% of the females were recovering from spawning respectively each year. Histological assessments of the same fish revealed that 20% in 1995, and nearly 60% of the fish in 1996 and 1997 showed physiological evidence of previous spawning. The proportion of recovering spawners increased with both length and age of the fish. One sample from the Northwest Atlantic Fisheries Organization area of 2J during October 1997 contained nearly 90% recovering fish. The potential impact of the fishery in light of the variability in post-spawning survival of the iteroparous female capelin is discussed.


2012 ◽  
Vol 69 (7) ◽  
pp. 1234-1241 ◽  
Author(s):  
Gail K. Davoren ◽  
Paulette Penton ◽  
Chantelle Burke ◽  
William A. Montevecchi

Abstract Davoren, G. K., Penton, P., Burke, C., and Montevecchi, W. A. 2012. Water temperature and timing of capelin spawning determine seabird diets. – ICES Journal of Marine Science, 69: . The capelin (Mallotus villosus) is the focal forage fish in many northern marine ecosystems. Its capacity to respond to changes in ocean climate is explored and the usefulness of seabird diets as indicators evaluated by integrating the timing of capelin spawning and temperature (0–150 m) during gonadal development (February–June) with colony-based measures of prey deliveries to chicks of common murres (Uria aalge) and northern gannets (Morus bassanus) on the east coast of Newfoundland during the years 1991–1993 and 2003–2010. Great variation was observed in the timing of spawning, with similar annual trends in different regions of coastal Newfoundland. Spawning was later in years of colder-than-average temperature, although the importance of other variables (e.g. fish size) could not be ruled out. The relationship between temperature during gonadal development and timing of spawning was weak at demersal spawning sites, suggesting that timing may be regulated by other factors (e.g. temperature at spawning sites). When spawning was early in warmer years relative to chick-rearing, common murres delivered a lower percentage of energy-rich gravid capelin to their chicks and northern gannets delivered a lower percentage of capelin. Integrating multiple data sources will be important to monitor marine ecosystem health as ocean climate changes.


2001 ◽  
Vol 58 (1) ◽  
pp. 73-85 ◽  
Author(s):  
J E Carscadden ◽  
K T Frank ◽  
W C Leggett

Capelin (Mallotus villosus), an important forage and commercial fish in the Northwest Atlantic, has exhibited dramatic changes in its biology during the 1990s, coincident with extreme oceanographic conditions and the collapse of major groundfish stocks. Commercial exploitation has not been a serious factor influencing the population biology of capelin in the area. The overall consumption of capelin has declined as predator stock abundances have changed. Data on plankton are sparse, but there appears to have been a decline in zooplankton abundance during the 1990s, and at the same time, a phytoplankton index increased. The impact of the changes in the physical environment has been the subject of previous studies and these are reviewed. The relative impacts of four factors, commercial exploitation, predation, food availability, and the physical environment, on the changes in capelin biology are discussed in the context of capelin as a single species and in the context of the ecosystem. The overall patterns suggest the existence of a "trophic cascade" within the distributional range of capelin in the Northwest Atlantic during the 1990s primarily driven by declines in major finfish predators.


2015 ◽  
Vol 93 (6) ◽  
pp. 447-460 ◽  
Author(s):  
L. McFarlane Tranquilla ◽  
W.A. Montevecchi ◽  
A. Hedd ◽  
P.M. Regular ◽  
G.J. Robertson ◽  
...  

To study the influence of inter- and intra-specific interactions on patterns of ecological segregation in nonbreeding habitat, we used geolocators to track year-round movements of congeneric and partially sympatric Thick-billed Murres (Uria lomvia (L., 1758)) and Common Murres (Uria aalge (Pontoppidan, 1763)) from seven Canadian colonies during 2007–2011. Locations from 142 individuals were (i) examined for species- and colony-specific spatiotemporal patterns, (ii) mapped with environmental data, and (iii) used to delineate core wintering areas. Compared with Common Murres, Thick-billed Murres dispersed across a wider range of latitudes and environments, had larger winter ranges, and showed greater variation in seasonal timing of movements. These interspecific differences were consistent at two scales: among colonies spanning a wide latitudinal range and at a sympatric colony. Intraspecifically, nonbreeding ecological segregation was more pronounced among colonies of Thick-billed Murres than of Common Murres: colonies of Thick-billed Murres tended to follow distinct movement patterns and segregate by latitude, whereas colonies of Common Murres segregated very little; moreover, the extent of segregation was more variable among Thick-billed Murres than Common Murres. For Thick-billed Murres, rather than complete divergence of winter ecological niche from Common Murres, we found a “widening” of an overlapping niche. This strategy of increased movement flexibility may enable Thick-billed Murres to mitigate competition both intra- and inter-specifically; we propose this movement strategy may have played a role in species divergence.


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