Differential use of zooplankton prey by Ancient murrelets and Cassin's auklets in the Queen Charlotte Islands

The distribution at sea and the food of two similar sized plankton-feedingalcids were examined during the 1981 breeding seasons in thenorthwestern Queen Charlotte Islands, British Columbia. Thetwo alcids, the Ancient murrelet (Synthliboramphus antiquus)and the Cassin's auklet (Prychoramphus aleuticus) have differentchick-rearing strategies. Both species fed predominantly atthe shelf break, although the Cassin's auklet also foraged overseamounts. The feeding distributions of the species appear tobe related to those of their prey. Zooplankton sampling indicatedthat each alcid selects a small and different portion of thezooplankton available in surface waters. The Ancient murrelet'smain foods were euphausiids (Thysanoessa spinifera and Euphausiapacifica) and larval and juvenile fishes. The Cassin's aukletchicks fed chiefly on calanoid copepods (Neocalanus cristatus).euphausiids (mostly Thysanoessa longipes in 1981, but in otheryears also Thysanoessa spinifera), and larval and juvenile fishes.The Cassin's auklets took smaller prey than the Ancient murrelet.Differences in the diets of the two alcid species were associatedwith differences in morphology and chick-rearing strategies.     

Olfactory navigation to the nesting burrow in Leach's petrel (oceanodroma leucorrhoa)

Visual, auditory, and olfactory navigation in the homing behaviour of Leach's petrel to the nesting burrow were investigated. Petrels returning to their burrows at night hovered above the thick spruce-fir canopy in the vicinity of the burrow before plummeting to the forest floor a few metres downwind of their burrows. They then walked upwind to their burrows. Birds landed closer to, and followed more circuitous routes to, their burrows in still air than in a wind. They failed to avoid obstacles in the path to burrows, often failed to locate accurately burrow entrances on first trial, and vocalized only after entering the burrow. In a Y-maze olfactorium, captive breeding petrels chose an air current coming from their own nest material in preference to one from similar materials collected on the forest floor. In the same apparatus, birds did not respond positively to air currents from their own stomach oil or preen gland oil. Petrels taken from burrows and released that same night did not return within a week if their external nares were plugged or if their olfactory nerves were transected. They did return if not operated on or if only subjected to sham operations. These results support an olfactory guidance system in burrow location and argue against visual or auditory guidance.     

The importance of bark products in the aboriginal economies of Northwestern British Columbia,Canada

In the coniferous forest dominated landscape of northwestern British Columbia, bark products were used to fill many needs which in less heavily forested environments were filled by herbaceous plants. Bark from woody shrubs and trees was used for carbohydrate food, medicine, fiber, and structural material. Use of the bark of twenty one species of woody plants is documented for the Gitksan, Wet’suwet’en and Haisla peoples of Northwest British Columbia. Approximately half of the woody species named by these peoples were used for bark resources. Today, most bark derived products have been replaced with manufactured and agricultural products.     

Rapid evolution in the Nebria gregaria group (Coleoptera: Carabidae) and the paleogeography of the Queen Charlotte Islands

Morphological differentiation in the ground beetles of the Nebria gregaria group, found on the Queen Charlotte Islands, has been used as support for the glacial refugium proposed for the northwest coast of North America. Two members of this species group, N. charlottae and N. louiseae, are restricted to cobble beaches in this archipelago. A third, N. haida, is found only in alpine regions of the archipelago and the adjacent mainland. The remaining two species of the gregaria group, N. lituyae and N. gregaria, show highly restricted distributions in the mountains of the Alaska panhandle and on the beaches of the Aleutian Islands, respectively. To determine the relationships of the five species, we conducted phylogenetic analyses on nucleotide sequence data obtained from five regions of the mitochondrial DNA. In total, 1835 bp were analyzed. The results suggest that one species, N. lituyae, does not belong in the gregaria group, and that only seven mutations separated the two most divergent of the four remaining species. We also conducted random amplified polymorphic DNA fingerprinting analyses on genomic DNA extracted from the five species. Analyses of genetic diversity revealed a lack of molecular differentiation among the Queen Charlotte species, suggesting that these populations may be postglacial in origin and that together N. gregaria, N. charlottae, N. louiseae, and N. haida might represent local variations of a single species. These results are consistent with conclusions derived for the morphological and genetical differentiation among Gasterosteus populations in the archipelago.     

Nutrient and phytoplankton dynamics in the Queen Charlotte Islands (Canada) during the summer upwelling seasons of 2001-2002

The Queen Charlotte Islands, Canada, lie at the northern extremeof the coastal upwelling system of the eastern North PacificOcean (51–54°N). In this study, the first observationsof spatial and inter-annual patterns in nutrient inventories,chlorophyll (Chl) a and phytoplankton assemblages are reportedand related to oceanographic conditions in near-shore watersof the island archipelago. Stronger and more persistent upwellingin 2002 coincided with higher nutrient and Chl a standing stockscompared to 2001 and a higher proportion of diatoms. Dinoflagellateswere more prevalent in 2001, including several potentially harmfulspecies. At sub-seasonal scales, Chl a concentrations were greatestduring downwelling conditions and smallest during upwellingconditions. On the west coast, weak water column stratification,high relative proportions of diatoms and large nutrient inventoriesaccompanied upwelling-favourable conditions, whereas on theeast coast, there was no direct relationship between the BakunUpwelling Index and water column stability. According to redundancyanalysis, variability in species composition was best explainedby sea surface temperature, the depth of the euphotic zone andnutrient inventories. The east coast supported blooms of coccolithophoreswithin protected bays, confirming previous satellite observationsthat showed bright patches in these areas. The data illustratethat moderate upwelling can have an important influence on near-shorealgal standing stocks and species composition at the northernextreme of the upwelling system off the west coast of NorthAmerica, and that topographical complexity may be importantfor the development of phytoplankton blooms.     

A comparison of growth and abundance for tidal pool fishes in California and British Columbia

A qualitative comparison of species compositions, relative abundances, diversity and growth was made between tidal pool fishes collected in Port Renfrew, British Columbia and Bruels Point, California. The two most preponderant cottid species Oligocottus maculosus and Clinocottus globiceps were aged using vertebrae, from which back calculated growth values were obtained. Species from Port Renfrew were found to have a higher diversity index, greater species composition and abundance. No growth differences were found between the two localities despite the 1120 km (700 miles) separating then.     

Evidence of luminous bacterial symbionts in the light organs of myctophid and stomiiform fishes

The myctophids and stomiiforms represent two common groups of luminous fishes, but the source of luminescence in these animals has remained undetermined. In this study, labeled luciferase gene fragments from luminous marine bacteria were used to probe DNA isolated from specific fish tissues. A positive signal was obtained from skin DNA in all luminous fishes examined, whereas muscle DNA gave a weaker signal and brain DNA was negative. This observation is consistent with luminous bacteria acting as the light source in myctophids and stomiiforms and argues against the genes necessary for luminescence residing on the fish chromosomes. To confirm the location of this signal, a bacterial probe was hybridized in situ to sections of a stomiiform. A strong signal was generated directly over specific regions of the fish light organs, whereas no signal was found over other internal or epidermal tissues of the fish. Taken together, these data provide the first indication that luminous bacterial symbionts exist in myctophids and stomiiforms and that these symbionts account for luminescence in these fishes.     

Modelling Infectious Hematopoietic Necrosis Virus Dispersion from Marine Salmon Farms in the Discovery Islands,British Columbia,Canada

Finite volume ocean circulation and particle tracking models are used to simulate water-borne transmission of infectious hematopoietic necrosis virus (IHNV) among Atlantic salmon (Salmo salar) farms in the Discovery Islands region of British Columbia, Canada. Historical simulations for April and July 2010 are carried out to demonstrate the seasonal impact of river discharge, wind, ultra-violet (UV) radiation, and heat flux conditions on near-surface currents, viral dispersion and survival. Numerical particles released from infected farm fish in accordance with IHNV shedding rates estimated through laboratory experiments are dispersed by model oceanic flows. Viral particles are inactivated by ambient UV radiation levels and by the natural microbial community at rates derived through laboratory studies. Viral concentration maps showing temporal and spatial changes are produced and combined with lab-determined minimum infectious dosages to estimate the infective connectivity among farms. Results demonstrate that neighbouring naïve farms can become exposed to IHNV via water-borne transport from an IHNV diseased farm, with a higher risk in April than July, and that many events in the sequence of farm outbreaks in 2001-2002 are consistent with higher risks in our farm connectivity matrix. Applications to other diseases, transfers between farmed and wild fish, and the effect of vaccinations are also discussed.     

The Abundance and Distribution of Wolverines in British Columbia,Canada

ABSTRACT The abundance and distribution of carnivores and their habitat are key information needed for status assessment, conservation planning, population management, and assessment of the effects of human development on their habitat and populations. We developed a habitat quality rating system, using existing wolverine (Gulo gulo) distribution, wolverine food, ecosystem mapping, and human development data. We used this and empirically derived estimates of wolverine density to predict wolverine distribution and abundance at a provincial scale. Density estimates for wolverines in high-quality habitat averaged 6.2 wolverines/1,000 km² (95% CI = 4.2–9.5). We predicted mean densities ranging from 0.3/1,000 km² in rare-quality habitat to 4.1/1,000 km² in moderate-quality habitat. Our predicted population estimate for wolverines in British Columbia was 3,530 (95% CI = 2,700-4,760). We predicted highest densities of wolverines in interior mountainous regions, moderate densities in interior plateau and boreal forest regions, and low densities in mainland coastal regions and drier interior plateaus. We predicted that wolverines would be rare on Vancouver Island, along the outer mainland coast, and in the dry interior forests, and absent from the Queen Charlotte Islands, interior grassland environments, and areas of intensive urban development.     

Seasonal and annual variation in the diet of breeding and non-breeding Wilson's storm-petrels on King George Island, South Shetland Islands

The diet of breeding and non-breeding Wilson's storm-petrels (Oceanites oceanicus) was analysed over four breeding seasons on King George Island, South Shetland Islands, in order to test if there are changes in diet composition within and between seasons. Krill was the most important food item, followed by myctophid fish and amphipods. Breeding birds showed a clear seasonal pattern of diet, with krill decreasing and alternative prey increasing from the incubation to the chick-rearing period. Non-breeders were not found to change their diet composition. The data suggest that Wilson's storm-petrels selectively choose alternative prey to krill in order to meet the nutrient demands of their chicks. In years of low food availability, Wilson's storm-petrels may have a limited option of prey choice.     

The inshore fishes of Heard and McDonald Islands, Southern Indian Ocean

Using histological and cytological criteria, it has been shown that in the ovotestis of Serranus hepatus , a synchronous hermaphrodite, the differentiation of the ovary is earlier than that of the testis. Primordial germ cells (PGC) exhibit the same ultrastructural features in the ovary and the testis. These cells migrate from the ovary to colonize the testicular anlage.     

The scarcer freshwater fishes of the British Isles

This, the first of two papers on the scarcer freshwater fishes of the British Isles, gives an account of the introduced species. Nineteen species are included. The natural distribution of these fishes, the history of their introduction, their success in acclimatization, and their present distribution in the British Isles are given. A brief discussion on the introduction of exotic fishes to aquatic ecosystems follows.     

Plant communities and plant production in the western Queen Elizabeth Islands

A study of soils, plant communities, and net annual plant production was conducted with 41 stands at 3 sites on 3 arctic islands. Twelve additional sites were studied in less detail on Ellef Ringnes, King Christian and Melville islands and on four other islands. Through polar ordination five groupings were recognized. Alopecurus and Puccinellia barrens on sand to silty soils and on silty soils, high in sodium salts respectively. Species richness averaged 2.6 ± 2.0 and total plant cover 6.8 ± 2.7%. The Phippsia barrens occur on sheet eroded surfaces and in gulleys with deep winter snow. Species richness was 9.8 ± 5.0 and total plant cover 14.8 ± 9.6%. The graminoid steppes on sandy soils averaged 7.6 ± 2.4 species and total plant cover 40.0 ± 2.8%. Eight stands were dominated by moss-graminoids, mostly on loam soils. Species richness was 24.9 ± 3.4 and total plant cover 77.7 ± 16.1%. Plant producion was 8.0 g m⁻² in a Puccinellia barren and 9.4 g m⁻² in a Luzula confusa graminoid steppe. Net annual production ranged from 18.8 to 58.7 in 6 other stands. The 13 stands within the cryptogam-herb community complex occur on sandy loam to clay-loam soils. Species richness averaged 26.3 ± 6.2 and total plant cover 61.2 ± 24.7%.
Mosses and lichens play a significant role in the establishment and maintenance of communities with a greater species richness and plant production of vascular plant species. The ability of mosses to hold moisture and the presence of limited bluegreen algae that fix nitrogen appear essential to the maintenance of greater species richness, plant cover and plant production compared with the barren polar deserts that are often nearby.     

Status and management of white sturgeon in the Columbia River in British Columbia, Canada: an overview

White sturgeon ( Acipenser transmontanus ) in the Columbia River in Canada have recently been listed as Endangered/Critically Imperiled, based on a shift in size and age-class composition from a population dominated by juveniles in the early 1980s to one presently dominated by adults. This shift has been attributed to a poor survival of early life stages. To determine the causes for this poor survival, investigations conducted annually since 1990 have focussed on identifying white sturgeon movement patterns, population dynamics, reproductive biology, and critical habitats. The reasons for the low recruitment remain poorly understood but river regulation and reservoir formation due to dam construction and pollution from municipal and industrial effluent inputs are suspected as contributing factors.
The history of dam development on the Columbia River and implications to white sturgeon are discussed from a historical perspective. A synopsis of post-1990 study results is provided and discussed in the framework of management strategies that include: 1) angling regulations, 2) flow enhancement strategies during spawning, 3) development of a population stabilization plan, 4) investigations into the feasibility of artificial stock supplementation, and 5) proposed future study programs to identify factors limiting recruitment.