Diving depths, diet, and underwater foraging of Rhinoceros Auklets in British Columbia

1993 ◽  
Vol 71 (12) ◽  
pp. 2528-2540 ◽  
Author(s):  
Alan E. Burger ◽  
Rory P. Wilson ◽  
Don Garnier ◽  
Marie-Pierre T. Wilson
Keyword(s):  
British Columbia ◽  
Prey Availability ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Ammodytes Hexapterus ◽  
Bite Marks ◽  
Important Prey ◽  
Cerorhinca Monocerata ◽  
Pacific Sand Lance ◽  
The Mean

Rhinoceros Auklets (Cerorhinca monocerata) were studied at Triangle Island, Cleland Island, and Seabird Rocks, British Columbia, in 1986–1989. Epipelagic schooling fish were consistently the most common prey delivered to auklet chicks at all three localities. Pacific sand lance (Ammodytes hexapterus), Pacific herring (Clupea harengus), juvenile salmon (Onchorhyncus spp.), Pacific saury (Cololabis saura), and juvenile rockfish (Sebastes spp.) were important prey. Bite marks on the fish showed that 73% were attacked from below. The mean deepest depth recorded for 16 auklets was 30 m (range 12–60 m). Eleven time-at-depth records showed that the auklets were epipelagic foragers: 90% of the mean underwater time was spent in the upper 10 m, although most birds had a few deeper dives of 20–60 m. Shipboard transects showed that Rhinoceros Auklets usually foraged in water considerably deeper than 15 m. A model of diving efficiency indicated that a relatively large proportion (> 40%) of the average dive cycle was spent foraging rather than travelling or resting, and prolonged dives invoking anaerobic glycolysis were avoided. We discuss the implications of diving limitations on foraging behaviour and the use of Rhinoceros Auklets as indicators of prey availability.

Rhinoceros Auklet (Cerorhinca monocerata) Nestling Diet May Gauge Pacific Sand Lance (Ammodytes hexapterus) Recruitment

1993 ◽  
Vol 50 (9) ◽  
pp. 1908-1915 ◽  
Author(s):  
Douglas F. Bertram ◽  
Gary W. Kaiser
Keyword(s):  
British Columbia ◽  
Sand Lance ◽  
Ammodytes Hexapterus ◽  
Nestling Diet ◽  
Cerorhinca Monocerata ◽  
Pacific Sand Lance ◽  
Term Monitoring ◽  
Rhinoceros Auklet ◽  
Seabird Colonies

We studied (1984–86) the diet of rhinoceros auklet (Cerorhinca monocerata) nestlings at three colonies on the British Columbia coast (Lucy islands, Pine Island, and Triangle Island). On the Lucy Islands, Pacific sand lance (Ammodytes hexapterus) dominated nestling food loads in all years. In 1985, 0+ sand lance dominated the nestling diet on all colonies. Concurrent measures of nestling growth rate, independent indexes of ocean production, and the proportion of sand lance in groundfish stomach samples were also highest in 1985. This suggests a linkage between ocean production, 0+ sand lance abundance, and events on seabird colonies over a broad geographic range. We emphasize the importance of sand lance to temperate seabirds and contrast British Columbia with areas where sand lance are commercially exploited. Rhinoceros auklet nestling diet, growth, and other data collected on colonies suggest that long-term monitoring on seabird colonies can contribute timely and inexpensive information on the recruitment of sand lance stocks in Canadian waters.

Factors Affecting the Distribution, Abundance, and Measurement of Pacific Herring (Clupea harengus pallasi) Spawn

1987 ◽  
Vol 44 (6) ◽  
pp. 1181-1194 ◽  
Author(s):  
D. E. Hay ◽  
A. R. Kronlund
Keyword(s):  
Survey Methods ◽  
Abiotic Factors ◽  
Early Years ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Biological Factors ◽  
Factors Affecting ◽  
Clupea Harengus Pallasi ◽  
The Mean ◽  
Stock Abundance

Records of the date, location, and magnitude of Pacific herring (Clupea harengus pallasi) spawnings in British Columbia, collected since 1928, were compiled and analysed. In the early years of spawn surveys, adjacent spawnings were often reported as single events. Gradually, this practice has changed so that each spawning has a separate record. As a consequence of this change in methods, the mean length of spawnings has decreased in recent years but the total numbers of records has increased. Estimates of mean spawning width and intensity have also changed, partly due to changing survey methods as well as changing spawning distributions. A spawn abundance index is developed to account for these temporal changes. Abiotic factors affecting the distribution and abundance of spawn deposition include sea surface temperatures and the fishery. Biological factors affecting spawn distribution and abundance are not as well defined, but it is shown that in some situations, spawn dimensions may change as a function of stock abundance.

Predation by Medusae on Pacific Herring (Clupea harengus pallasi) Larvae

1982 ◽  
Vol 39 (11) ◽  
pp. 1537-1540 ◽  
Author(s):  
Mary Needler Arai ◽  
Douglas E. Hay
Keyword(s):  
British Columbia ◽  
Coastal Waters ◽  
Laboratory Tests ◽  
Clupea Harengus ◽  
Aurelia Aurita ◽  
Pacific Herring ◽  
Aequorea Victoria ◽  
Clupea Harengus Pallasi

In laboratory tests young Pacific herring (Clupea harengus pallasi) larvae were eaten by several species of hydromedusae common in coastal waters off British Columbia, including the previously controversial Sarsia tubulosa and by the scyphomedusa Aurelia aurita. Field collections and observations confirmed that the distributions of medusae and larvae overlap and that some medusae feed on herring larvae in nature. In coastal waters and bays of British Columbia, the hydromedusae Sarsia tubulosa or Aequorea victoria may be most abundant during the time of peak herring larvae abundance.Key words: herring, larvae, Clupea, Sarsia, Aequorea, predation, medusae

Feeding ecology of the ancient and marbled murrelets near Langara Island, British Columbia

1975 ◽  
Vol 53 (4) ◽  
pp. 418-433 ◽  
Author(s):  
Spencer G. Sealy
Keyword(s):  
British Columbia ◽  
Feeding Ecology ◽  
Prey Availability ◽  
Breeding Cycle ◽  
Marbled Murrelet ◽  
Ammodytes Hexapterus ◽  
Queen Charlotte Islands ◽  
Early Portion ◽  
Marbled Murrelets

Two field seasons (1970 and 1971) were spent studying the feeding ecology of the ancient murrelet (Synthliboramphus antiquus) and the marbled murrelet (Brachyramphus marmoratus) near Langara Island, Queen Charlotte Islands, British Columbia. The relatively offshore-feeding ancient murrelet nests in colonies, lays two-egg clutches, and has truly precocial young. The inshore-feeding marbled murrelet is apparently a solitary nester, has one-egg clutches, and semiprecocial young. The ancient murrelet feeds predominantly on two species of euphausiid crustaceans, Euphausia pacifica and Thysanöessa spinifera, during the early portion of the terrestrial phase of its breeding cycle (early April to late May), but takes a fish, Ammodytes hexapterus, toward the end of the cycle. It is believed that this change in diet as the season progresses reflects a change in prey availability. The apparent patchy distribution of the prey of the ancient murrelet, which requires more time to locate the food source, has probably promoted the evolution of the 72-h incubation shifts found in this species.During the terrestrial phase of the marbled murrelet's breeding cycle (early May to late August), the fish Ammodytes hexapterus and Cymatogaster aggregata are predominantly taken. During the very early part of its breeding season, Thysanöessa spinifera constitutes a considerable part of its diet.

A Record of Pacific Herring (Clupea harengus pallasi) Feeding on Juvenile Chinook Salmon (Oncorhynchus tshawytscha) in a British Columbia Estuary

1971 ◽  
Vol 28 (12) ◽  
pp. 1921-1921 ◽  
Author(s):  
Jun Ito ◽  
R. R. Parker
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Predator Prey ◽  
Juvenile Chinook Salmon ◽  
Clupea Harengus Pallasi ◽  
Juvenile Chinook

An occurrence of Pacific herring (Clupea harengus pallasi) predation on juvenile chinook salmon (Oncorhynchus tshawytscha) is described. This is the first recorded incidence of this particular predator–prey relation.

Stream salmonids as opportunistic foragers: the importance of terrestrial invertebrates along a stream-size gradient

2011 ◽  
Vol 68 (12) ◽  
pp. 2146-2156 ◽  
Author(s):  
J. Syrjänen ◽  
K. Korsu ◽  
P. Louhi ◽  
R. Paavola ◽  
T. Muotka
Keyword(s):  
Diet Composition ◽  
Aquatic Invertebrates ◽  
Prey Availability ◽  
Deciduous Forests ◽  
Terrestrial Invertebrates ◽  
Important Prey ◽  
Stream Salmonids ◽  
The Mean ◽  
Forest Streams ◽  
Size Gradient

Terrestrial invertebrates have been reported to be positively selected by stream salmonids. We assessed the importance of terrestrial and aquatic invertebrates to salmonid diets in 25 streams in Finland, with the hypothesis that terrestrial prey would be important in only the smallest forest streams. Several measures of prey availability were used, including proportional abundance in benthic or drift samples, compared with a trait-based approach, to predict diet composition. Across all 25 streams in autumn, blackfly and caddis larvae were the most important prey items. Terrestrial invertebrates were of moderate importance in all streams, including the smallest. Pure availability predicted diet best and provided, in most cases, a significant fit with the observed diet. In a quantitative literature review, the mean proportion of terrestrial prey in salmonid diets was 17%, being highest for the largest fish (≥15 cm). Species of the genus Salmo consumed significantly less terrestrials than did other salmonid genera. The proportion of terrestrial prey was highest in streams flowing through deciduous forests, but it was only weakly correlated with channel width.

scholarly journals Diet of the Pacific Sand Lance (Ammodytes hexapterus) in the Salish Sea, British Columbia, in the 1960s

2014 ◽  
Vol 128 (1) ◽  
pp. 57 ◽  
Author(s):  
J. Mark Hipfner ◽  
Moira Galbraith
Keyword(s):  
British Columbia ◽  
Stomach Contents ◽  
Salish Sea ◽  
Sand Lance ◽  
Strait Of Georgia ◽  
Ammodytes Hexapterus ◽  
Saanich Inlet ◽  
The Pacific ◽  
Pacific Sand Lance ◽  
Calanus Marshallae

The diet of the Pacific Sand Lance (Ammodytes hexapterus) was quantified from the stomach contents of 115 Pacific Sand Lance caught in the Strait of Georgia and Saanich Inlet (Vancouver Island) in the Salish Sea, British Columbia, in the spring and summer of 1966, in the Strait of Georgia in the spring and summer of 1967, and in the Strait of Georgia and Saanich Inlet in the spring and summer of 1968. There were 12 major taxa of prey in diets, 8 of which were Crustacea. Based on an index of relative importance, copepods were the dominant prey in 1966 and 1968, but not in 1967, when cladocerans, larvaceans, and teleosts also were common. The copepods Pseudocalanus spp. and Calanus marshallae were the only taxa to appear in diets in all three years. Pseudocalanus dominated the copepod component of diets in 1966, when sampling occurred in July; unspecified copepod nauplii (an early larval stage) were dominant in 1967 and 1968, when sampling occurred earlier (April to June). With the profound changes that have occurred in the Salish Sea over recent decades, these data can serve as a baseline for comparison.

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