Diel Vertical Movements and Feeding of Underyearling Sockeye Salmon and the Limnetic Zooplankton in Babine Lake, British Columbia

1970 ◽  
Vol 27 (2) ◽  
pp. 281-316 ◽  
Author(s):  
David W. Narver
Keyword(s):  
British Columbia ◽  
Surface Waters ◽  
Sockeye Salmon ◽  
Lower Layer ◽  
Standing Stock ◽  
Vertical Movement ◽  
Vertical Movements ◽  
The North ◽  
Bosmina Coregoni ◽  
Terrestrial Insects

The use of a high frequency echo sounder and a midwater trawl in Babine Lake, British Columbia, in 1967 revealed a precise diel vertical movement of underyearling sockeye salmon. From early July to September, from about 1.5 hr after sunrise to 1.5 hr before sunset, the young sockeye were in two distinct layers at about 20 and 35 m, each layer about 6 m thick. About 1.5 hr before sunset the two layers began to ascend. About 0.5 hr after sunset all fish were within 3 m of the surface, and during darkness they were dispersed throughout the top 5–15 m with most fish being below the thermocline. Soon after the first light of dawn the fish usually tended to move toward the lake surface and then descended rapidly to the daytime depths.By early October the pattern had changed markedly. During daylight the fish were still found in roughly two layers at about 24 and 40 m. However, the evening ascent did not commence until about 0.5 hr before sunset, the ascent was much slower, and the fish did not come to the surface but were dispersed between 9 and 27 m. This change in behaviour was temporally associated with a cooling of the epilimnion and a decrease in intensity of feeding.Although the zooplankton of Babine Lake is composed of eight major species, only Bosmina coregoni and the calanoid copepod Heterocope septentrionalis displayed pronounced diel vertical movements. The former inhabited the surface waters during the day and were found in maximum abundance at 12–21 m at night. The latter was found at 21–30 m during the day and the surface waters at night. The major part of the zooplankton standing stock was found above 9 m.Young sockeye fed most intensively in the evening as they approached the surface and again at dawn just as they commenced the descent. At those times the most common food item was Daphnia longispina, followed by B. coregoni and H. septentrionalis. These three species were strongly selected by young sockeye, since they were numerically much less abundant than other limnetic zooplankton species. In August, terrestrial insects were occasionally of major importance. At midday the upper layer of sockeye (about 20 m) was feeding on H. septentrionalis whereas the lower layer (about 35 m) was not feeding or was feeding at a low intensity.The double layer of young sockeye during daylight occurred at least in the North Arm of Babine Lake and may be related to feeding. In July and August the fish in the upper layer had less food in the pyloric section of the stomach from 0900 to 1300 hr than did fish in the lower layer, whereas the volumes of food were similar in the two layers by late afternoon. Fish in the upper layer had much more fresh H. septentrionalis in the cardiac section from 1200 to 1800 hr than did fish in the lower layer. The ecological significance of the diel vertical movement is discussed briefly.

scholarly journals Horizontal and Vertical Movement Patterns and Habitat Use of Juvenile Porbeagles (Lamna nasus) in the Western North Atlantic

2021 ◽  
Vol 8 ◽  
Author(s):  
Gregory Skomal ◽  
Heather Marshall ◽  
Benjamin Galuardi ◽  
Lisa Natanson ◽  
Camrin D. Braun ◽  
...  
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Gulf Stream ◽  
Gulf Of Maine ◽  
Habitat Preferences ◽  
Fork Length ◽  
Vertical Movement ◽  
Vertical Movements ◽  
The North ◽  
History Of

The porbeagle (Lamna nasus) is a large, highly migratory endothermic shark broadly distributed in the higher latitudes of the Atlantic, South Pacific, and Indian Oceans. In the North Atlantic, the porbeagle has a long history of fisheries exploitation and current assessments indicate that this stock is severely overfished. Although much is known of the life history of this species, there is little fisheries-independent information about habitat preferences and ecology. To examine migratory routes, vertical behavior, and environmental associations in the western North Atlantic, we deployed pop-up satellite archival transmitting tags on 20 porbeagles in late November, 2006. The sharks, ten males and ten females ranging from 128 to 154 cm fork length, were tagged and released from a commercial longline fishing vessel on the northwestern edge of Georges Bank, about 150 km east of Cape Cod, MA. The tags were programmed to release in March (n = 7), July (n = 7), and November (n = 6) of 2007, and 17 (85%) successfully reported. Based on known and derived geopositions, the porbeagles exhibited broad seasonally-dependent horizontal and vertical movements ranging from minimum linear distances of 937 to 3,310 km and from the surface to 1,300 m, respectively. All of the sharks remained in the western North Atlantic from the Gulf of Maine, the Scotian Shelf, on George's Bank, and in the deep, oceanic waters off the continental shelf along the edge of, and within, the Gulf Stream. In general, the population appears to be shelf-oriented during the summer and early fall with more expansive offshore radiation in the winter and spring. Although sharks moved through temperatures ranging from 2 to 26°C, the bulk of their time (97%) was spent in 6-20°C. In the summer months, most of the sharks were associated with the continental shelf moving between the surface and the bottom and remaining < 200 m deep. In the late fall and winter months, the porbeagles moved into pelagic habitat and exhibited two behavioral patterns linked with the thermal features of the Gulf Stream: “non-divers” (n = 7) largely remained at epipelagic depths and “divers” (n = 10) made frequent dives into and remained at mesopelagic depths (200–1000 m). These data demonstrate that juvenile porbeagles are physiologically capable of exploiting the cool temperate waters of the western North Atlantic as well as the mesopelagic depths of the Gulf Stream, possibly allowing exploitation of prey not available to other predators.

Primary Productivity in the Babine Lake System, British Columbia

1967 ◽  
Vol 24 (10) ◽  
pp. 2045-2052 ◽  
Author(s):  
David W. Narver
Keyword(s):  
British Columbia ◽  
Primary Productivity ◽  
Sockeye Salmon ◽  
Carbon Fixation ◽  
Euphotic Zone ◽  
High Rate ◽  
The North ◽  
Lake Region ◽  
Rate Of Photosynthesis ◽  
Main Lake

Primary productivity in Babine Lake, British Columbia, as measured by the C14 in situ method in 1966 was slightly lower in the North Arm (outlet) and Morrison Arm (an inlet) than in the main lake region. An unusually high rate of photosynthesis at one part of the main lake in September may have been related to the decomposition of salmon carcasses in a nearby stream. Morrison Lake, a major tributary, was much lower in rate of photosynthesis, pH, alkalinity, compensation depth, and total dissolved solids than any part of Babine Lake. The rate of carbon fixation of Babine Lake was much less on a per unit area basis than those reported by other workers for the majority of 24 sockeye salmon lakes in southwestern Alaska but was similar to most per unit volume of the euphotic layer. Much of this difference is attributable to a shallower euphotic zone in Babine Lake. Ranked with the 24 Alaskan lakes, Babine was first in alkalinity, third in TDS, and fifth in pH.The productivity measurements suggest that the carrying capacity for sockeye salmon per unit of nursery area of the main lake region is at least as great as that of the North Arm.

Age-specific effects of sockeye abundance on adult body size of selected British Columbia sockeye stocks

1995 ◽  
Vol 52 (5) ◽  
pp. 1050-1063 ◽  
Author(s):  
Skip McKinnell
Keyword(s):  
British Columbia ◽  
Pacific Ocean ◽  
North Pacific ◽  
Sockeye Salmon ◽  
North Pacific Ocean ◽  
Common Factor ◽  
Bristol Bay ◽  
The North ◽  
Skeena River ◽  
The North Pacific

Annual mean body lengths of adult sockeye salmon (Oncorhynchus nerka) covary systematically from year to year in major northern and central British Columbia stocks (Nass River, Skeena River, and Rivers Inlet). These positive correlations are greatest between sexes within rivers, followed by age-classes among rivers. A common factor or factors affecting sockeye length in the North Pacific Ocean is suggested. The mean length of age 1.3 sockeye salmon but not age 1.2 sockeye caught annually in these B.C. fisheries was negatively correlated with the magnitude of Bristol Bay (western Alaska) sockeye catches. During the spring of maturation, age 1.3 sockeye from these B.C. stocks were further from their natal streams, and likely subject to more intense competition with Bristol Bay sockeye than age 1.2 sockeye. The pattern of annual marine growth measured from Skeena River sockeye scales collected during the 1960s provides additional evidence that the length of age 1.3 sockeye was related to Bristol Bay sockeye abundance in the year of maturation. No such correlation was evident in scales collected from age 1.2 sockeye. These results suggest that sockeye populations have more systematic distributions in the North Pacific Ocean than has been previously reported.

SHAPE AND HYDRODYNAMIC PROPERTIES IN RELATION TO SIZE IN MARINE MACRO-CRUSTACEA

Crustaceana ◽  
1999 ◽  
Vol 72 (2) ◽  
pp. 203-214 ◽  
Author(s):  
Keyword(s):  
Aquatic Environment ◽  
Geometric Model ◽  
Vertical Movement ◽  
Hydrodynamic Properties ◽  
Friction Coefficients ◽  
Vertical Movements ◽  
Size And Shape ◽  
The North ◽  
Physical Independence ◽  
Ellipsoid Of Revolution

AbstractIn an aquatic environment, the hydrodynamic properties of animals strongly determine their transport and distribution. In macro-crustaceans, lacking well developed capabilities for regulating their specific gravity, hydrodynamic properties are to a large extent determined by their body size and body shape. For 96 macroscopic crustacean species, commonly occurring in the North Sea and eastern Atlantic, data regarding their (adult) body dimensions were fitted into a simple geometric model (an ellipsoid of revolution), which permitted the assessment of their hydrodynamic friction for horizontal and vertical movements. Friction coefficients for horizontal and vertical movement appear to be closely related to each other, vertical friction always being higher. Friction coefficients increase in species with size, but the volume-specific friction coefficients decrease, confirming a higher locomotory freedom in larger species. In the aquatic environment physical freedom is strongly limited by hydrodynamic factors. Certain changes in size and shape can increase physiological and physical independence. In this way crustaceans found many ways to escape the hydrodynamical limitations of their environment. A large variation in size and shape within the subphylum is still preserved. Dans un environnement aquatique, les proprietes hydrodynamiques des aminaux determinent fortement leur transport et leur distribution. Chez les macro-crustaces, qui manquent de capacites bien developpees pour la regulation de leur gravite specifique, les proprietes hydrodynamiques sont dans une large mesure determinees par la taille et la forme de leur corps. Pour 96 especes macroscopiques de crustaces, communement presentes dans la mer du Nord et l'est de l'Atlantique, les donnees relatives aux dimensions de leur corps (chez les adultes) on ete entrees dans un modele geometrique simple (ellipso de de revolution), ce qui a permis d'evaluer leur friction hydrodynamique pour des mouvements vertical et horizontal. Les coefficients de friction pour les mouvements vertical et horizontal apparaissent comme etroitement lies l'un a l'autre, la friction verticale etant toujours plus elevee. Les coefficients de friction croissent avec la taille, mais les coefficients de friction en volume specifique decroissent, ce qui confirme une plus grande liberte locomotrice chez les plus grandes especes. Dans l'environnement aquatique, la liberte physique est fortement limitee par des facteurs hydrodynamiques. Certains changements dans la taille et la forme peuvent accro tre l'independance physique et physiologique. Ainsi, les crustaces ont trouve beaucoup de moynes pour echapper aux limitations hydrodynamiques de leur environnement. Une large variation dans la taille et la forme est encore preservee a l'interieur du subphylum.

scholarly journals Physiological resilience of pink salmon to naturally occurring ocean acidification

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Andrea Y Frommel ◽  
Justin Carless ◽  
Brian P V Hunt ◽  
Colin J Brauner
Keyword(s):  
British Columbia ◽  
Elevated Co2 ◽  
Condition Factor ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Hypoxia Tolerance ◽  
High Co2 ◽  
The North ◽  
Naturally Occurring ◽  
Co2 Levels

Abstract Pacific salmon stocks are in decline with climate change named as a contributing factor. The North Pacific coast of British Columbia is characterized by strong temporal and spatial heterogeneity in ocean conditions with upwelling events elevating CO2 levels up to 10-fold those of pre-industrial global averages. Early life stages of pink salmon have been shown to be affected by these CO2 levels, and juveniles naturally migrate through regions of high CO2 during the energetically costly phase of smoltification. To investigate the physiological response of out-migrating wild juvenile pink salmon to these naturally occurring elevated CO2 levels, we captured fish in Georgia Strait, British Columbia and transported them to a marine lab (Hakai Institute, Quadra Island) where fish were exposed to one of three CO2 levels (850, 1500 and 2000 μatm CO2) for 2 weeks. At ½, 1 and 2 weeks of exposure, we measured their weight and length to calculate condition factor (Fulton’s K), as well as haematocrit and plasma [Cl−]. At each of these times, two additional stressors were imposed (hypoxia and temperature) to provide further insight into their physiological condition. Juvenile pink salmon were largely robust to elevated CO2 concentrations up to 2000 μatm CO2, with no mortality or change in condition factor over the 2-week exposure duration. After 1 week of exposure, temperature and hypoxia tolerance were significantly reduced in high CO2, an effect that did not persist to 2 weeks of exposure. Haematocrit was increased by 20% after 2 weeks in the CO2 treatments relative to the initial measurements, while plasma [Cl−] was not significantly different. Taken together, these data indicate that juvenile pink salmon are quite resilient to naturally occurring high CO2 levels during their ocean outmigration.

Phthalate Esters and Other Industrial Organic Chemicals in the North and Irish Seas

1991 ◽  
Vol 24 (10) ◽  
pp. 127-134 ◽  
Author(s):  
R. J. Law ◽  
T. W. Fileman ◽  
P. Matthiessen
Keyword(s):  
Surface Waters ◽  
Phthalate Esters ◽  
Organic Chemicals ◽  
Ion Detection ◽  
Ecotoxicological Assessment ◽  
Industrial Activities ◽  
The North ◽  
Detection Mode

Concentrations of a range of industrial organic chemicals (xylene, styrene, chlorobenzene and five phthalate esters) have been determined in surface waters near the Humber, Mersey, Tamar, Tees and Tyne estuaries. Analyses were conducted using GC/MS in the multiple ion detection mode. In general, the highest concentrations (in the ng to µg dm−3 range) for all determinands were found at sites within the estuaries. Selected samples were also analysed by scanning GC/MS and other compounds tentatively identified. There was only minor overlap between the compounds found at each of the estuaries, presumably a reflection of the industrial activities in the area. A preliminary ecotoxicological assessment was made of both datasets.

scholarly journals Gitksan

2016 ◽  
Vol 46 (3) ◽  
pp. 367-378 ◽  
Author(s):  
Jason Brown ◽  
Henry Davis ◽  
Michael Schwan ◽  
Barbara Sennott
Keyword(s):  
British Columbia ◽  
The South ◽  
The West ◽  
The North

Gitksan (git) is an Interior Tsimshianic language spoken in northwestern British Columbia, Canada. It is closely related to Nisga'a, and more distantly related to Coast Tsimshian and Southern Tsimshian. The specific dialect of Gitksan presented here is what can be called Eastern Gitksan, spoken in the villages of Kispiox (Ansbayaxw), Glen Vowell (Sigit'ox), and Hazelton (Git-an'maaxs), which contrasts with the Western dialects, spoken in the villages of Kitwanga (Gitwingax), Gitanyow (Git-anyaaw), and Kitseguecla (Gijigyukwhla). The primary phonological differences between the dialects are a lexical shift in vowels and the presence of stop lenition in the Eastern dialects. While there exists a dialect continuum, the primary cultural and political distinction drawn is between Eastern and Western Gitksan. For reference, Gitksan is bordered on the west by Nisga'a, in the south by Coast Tsimshian and Witsuwit'en, in the east by Dakelh and Sekani, and in the north by Tahltan (the latter four of these being Athabaskan languages).

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