Central British Columbia Coast Research Articles

Population Structure of Dungeness Crab (Cancer magister) in British Columbia

Population structure of Dungeness crab (Cancer magister) from British Columbia was evaluated from a survey of variation of eight microsatellite loci in eight populations. Genetic differentiation among the populations surveyed was observed, with the mean Fst for all loci 0.031 (SD ¼ 0.007). The Alison Sound population in the British Columbia central coast displayed less genetic variation and was distinct from all other populations in British Columbia, with pairwise Fst values>0.12, over 20 times the differentiation in other comparisons. The results were consistent with a high level of retention of larval crabs within Alison Sound, owing to reduced water exchange between the sound and adjacent waters. There was no evidence for an isolation by distance model of population structure of Dungeness crab in British Columbia, but there was some indication of differentiation between a west coast Vancouver Island population and a population adjacent to the southern Strait of Georgia.

Estimating Carrying Capacity for Sea Otters in British Columbia

ABSTRACT We estimated carrying capacity for sea otters (Enhydra lutris) in the coastal waters of British Columbia, Canada, by characterizing habitat according to the complexity of nearshore intertidal and sub‐tidal contours. We modeled the total area of complex habitat on the west coast of Vancouver Island by first calculating the complexity of the Checleset Bay‐Kyuquot Sound (CB‐KS) region, where sea otters have been at equilibrium since the mid‐1990s. We then identified similarly complex areas on the west coast of Vancouver Island (WCVI model), and adapted the model to identify areas of similar complexity along the entire British Columbia coast (BC model). Using survey data from the CB‐KS region, we calculated otter densities for the habitat predicted by the 2 models. The density estimates for CB‐KS were 3.93 otters/km2 and 2.53 otters/km2 for the WCVI and BC models, respectively, and the resulting 2 estimates of west coast of Vancouver Island complex habitat carrying capacity were not significantly different (WCVI model: 5,123, 95% CI = 3,337–7,104; BC model: 4,883, 95% CI = 3,223–6,832). The BC model identified the region presently occupied by otters on the central British Columbia coast, but the amount of coast‐wide habitat it predicted (5,862 km2) was relatively small, and the associated carrying capacity estimate (14,831, 95% CI = 9,790–20,751) was low compared to historical accounts. We suggest that our model captured a type of high‐quality or optimum habitat prevalent on the west coast of Vancouver Island, typified by the CB‐KS region, and that suitable sea otter habitat elsewhere on the coast must include other habitat characteristics. We therefore calculated a linear, coast‐wide carrying capacity of 52,459 sea otters (95% CI = 34,264–73,489)—a more realistic upper limit to sea otters in British Columbia. Our carrying capacity estimates are helping set population recovery targets for sea otters in Canada, and our habitat predictions represent a first step in Critical Habitat identification. This habitat‐based approach to estimating carrying capacity is likely suitable for other nonmigratory, density‐dependent species.

APPARENT LATERALIZED BEHAVIOR IN GRAY WHALES FEEDING OFF THE CENTRAL BRITISH COLUMBIA COAST

AbstractA digital acoustic recording tag was used to examine the 3‐D orientation of gray whales feeding along the central British Columbia coast. A total of 96 feeding dives were recorded from six different whales. More than half (53.1%) of the whales' bottom time was spent rolled at an angle greater than 45°. Whales rolled an average of 2.9 times per feeding dive, and rolling behavior was often accompanied by a negative pitch angle. Out of 282 recorded rolls, 274 (97.2%) were to the right. Likewise, 98.5% of the total time spent rolled at an angle greater than 45° was spent rolled to the right. The gray whales in this study showed a significant right‐side bias on both an individual (P≤ 0.009) and group level (P < 0.001). Based on the findings of this study and previous reports of uneven baleen wear (Kasuya and Rice 1970), it is proposed that gray whales exhibit a population‐wide right‐side rolling bias similar in character to the 90/10 split of right handedness in humans.

Strategic reserve design in the central coast of British Columbia: integrating ecological and industrial goals

Few conservation reserves worldwide have been created in ways that are likely to promote the persistence of species, ecosystems, and ecological processes regarded as being representative of biological diversity. We demonstrate the application of newer approaches to systematic reserve design that could help stakeholders find designs that maximize simultaneously ecological, societal, and industrial goals. We created example reserve designs using the simulated annealing algorithm of SITES 1.0 and then contrasted these designs with a proposed reserve design negotiated as a multi stakeholder process for British Columbia's central coast. Our strategic approach recommended reserve designs that included greater proportions of key conservation elements identified by stakeholders without increasing the land area or timber volume in reserves currently under consideration for protection. Our examples demonstrate that strategic approaches to reserve design can facilitate the repeatable and efficient allocation of land to conservation and development and, therefore, represent an improvement on ad hoc methods. Readily available software facilitates the exploration of alternative conservation and societal values, incorporate the interests of multiple stakeholders, and provides a focus and catalyst for discussion at the planning table.

The Shoreline Fringe Forest and Adjacent Peatlands of the Southern Central British Columbia Coast

Four distinct vegetation types are found in close proximity along an exposed section of the southern central coast of British Columbia. A coastal fringe of coniferous forest a few hundred metres wide is separated by a steep ecotone from an inland peatland-forest complex. The objectives of this study were (1) to describe the plant communities along the transition from forest to peatland, and (2) to identify some of the major environmental factors associated with those communities using indicator plant analysis. The coastal forest is dominated by Thuja plicata, Tsuga heterophylla, Picea sitchensis, and Chamaecyparis nootkatensis. Characteristic understory species include Gaultheria shallon and Blechnum spicant. Inland from the coastal forest are transitional forest stands with a species-rich understory including Cornus canadensis, Hylocomium splendens, and Vaccinium parvifolium. The peatlands are poor fens characterized by thickets of Pinus contorta and Chamaecyparis nootkatensis among open areas dominated by species such as Sphagnum sp., Empetrum nigrum, Juniperus communis, and bogs characterized by Myrica gale, Eriophorum angustifolium, and Sanguisorba officinalis. Indicator plant analysis identified differences in the ground surface materials, soil moisture and nutrient regime between the vegetation types. The general trend is for an increase in soil moisture from the forest vegetation to the peatlands and a concurrent change from the Mor humus forms that dominate the coastal forest floor to the surface groundwater table of the peatlands. These environmental differences between forest and peatland are likely related to the steeper slopes typically found in the fringe forest vegetation.

Seasonal movements and foraging behaviour of northern resident killer whales (Orcinus orca) in relation to the inshore distribution of salmon (Oncorhynchusspp.) in British Columbia

The hypothesis that northern resident killer whales (Orcinus orca) move in response to the seasonal availability of salmon (Oncorhynchus spp.) was tested using sightings and acoustic recordings of whales and data on the timing and abundance of salmon in Johnstone Strait, off Vancouver Island, between 1984 and 1988, and from King Island, on the central British Columbia coast, for a 2-month period in 1989. Whales were most abundant in Johnstone Strait between July and October when salmon migrate through the strait. Individual whales seen in the strait during summer were observed around King Island in spring 1989, coinciding with local sockeye and chinook salmon runs. In Johnstone Strait during summer 1988, whales foraged along the shore and in areas of strong current, where salmon occur in high densities. However, less than half of the 16 pods in the northern resident community were present on more than 15% of summer days (1984–1988). The occurrence of 6 pods (A1, A4, A5, C1, D1, and H1) in Johnstone Strait during summer was positively and significantly associated with sockeye and pink salmon abundance, whereas pod G1 was positively and significantly associated with chum salmon. Although we demonstrate an association between certain pods and certain salmon species, we cannot determine whether this reflects the true preference of pods or represents differences in the whales' arrival times in Johnstone Strait that are related to other factors. Our data suggest that within the northern resident community, pods may have seasonal ranges.

A reconnaissance survey of late Quaternary sea levels, Bella Bella/Bella Coola region, central British Columbia coast

A preliminary relative sea level curve that covers the last 10 200 years is derived for the area of the islands and outer mainland centered on Bella Bella and Namu, the central coast of British Columbia. The curve shows postglacial emergence of 17 m over this period. The rate of emergence was ~0.6 m/100 year about 9000 BP, and present sea level was attained between 7000 and 8000 BP. Relative sea level continued to fall until the last few hundred to one thousand years BP when a marine transgression led to a rise of sea level and resultant erosion of many coastal Indian middens. Marine limits on the outer islands may reach 120 m asl, whereas in the middle part of the fiord country observed delta surfaces are lower (54–75 m asl). Elevations of raised deltas then attain ~150 m at fiord heads. A readvance of the ice front ≤ 12 210 ± 330 BP (GSC-1351) is suggested by the stratigraphy of one section.

Ocean Growth and Mortality of Pink and Chum Salmon

Records of length of pink and chum salmon computed from scale annuli are summarized, and are converted to show rate of growth in weight. Information is available on 11 pink stocks or groups of stocks originating at points from the Strait of Georgia to Sakhalin and Primorye, and for 7 chum stocks taken from Tillamook Bay to the Amur River and Sakhalin. Estimates of increase in weight from the time of formation of the final annulus to time of capture near shore vary from 190% to 590% for pinks maturing at age 1+, and from 60% to 92% for chums maturing at age 3+. At the end of the first year, pinks are computed to average 356 g in weight, and chums 287 g. Average instantaneous rate of growth per month in the final year is 0.28 for pinks and 0.12 for chums, each available locality being given equal weight. The seasonal distribution of growth in the final year has been estimated for pink salmon of the Bering Sea (by Birman) and for those of the central British Columbia coast (by LeBrasseur and Parker); for chum salmon an approximate seasonal distribution can be deduced from comparisons of growth rates. Combining these with the best available estimate of natural mortality (0.02 per month for salmon more than 30 cm long), calculations of net yield from high-seas fishing can be made for any desired date, and compared with the yield from a purely coastal fishery (the same escapement being provided in both cases). In all situations the catch taken on the high seas is less than that taken from the survivors of the same fish in coastal waters. The loss of yield exceeds 50% for pinks taken early in their final season, and also for chums taken early in their penultimate season.

The Trophic Status of Port John Lake, British Columbia

Port John Lake is situated on King Island on the central British Columbia coast. Area is about 0.35 square miles (910,000 sq. m.). The drainage basin is 3.6 square miles (9.3 sq. km.) with an igneous foundation supporting a coniferous forest. Annual precipitation is 116 inches (295.5 cm.). An oligotrophic lake, it has a volume development of 1.53 and a mean depth of 82.2 feet (25.1 m.). The thermal stratification is second order, temperate, of the Whipple classification. The summer heat income is approximately 11,000 gram-calories per sq. cm. The ratio of O2 in the hypolimnion to O2 in the epilimnion is 6.58. Total dissolved solids are 39 ppm. at the lake surface.Large amounts of organic matter are washed into the lake imposing a potential stress on its oligotrophy. However, dredge and net collections, which are dominated by chironomids and cladocerans, respectively, contained very few organisms. Plankton was most abundant in the surface water.Low production of organisms is partly the result of the heavy rainfall which dilutes the trophic stratum above the hypolimnion, and the small amount of sunlight reaching the lake.