A New Method for Allotting Effort to Individual Species in a Mixed-Species Trawl Fishery

1983 ◽  
Vol 40 (3) ◽  
pp. 352-360 ◽  
Author(s):  
S. J. Westrheim
Keyword(s):  
British Columbia ◽  
Fishing Effort ◽  
New Method ◽  
Individual Species ◽  
Western Canada ◽  
Species Comparison ◽  
Mixed Species ◽  
Important Species ◽  
Trawl Fishery ◽  
Rank 2

A new method is described which allots fishing effort to individual species in a multi-species trawl fishery in northern Hecate Strait, British Columbia. All-species effort and individual species' landings are arranged by depth in selected area–time cells. In each area–time cell, each species is allotted the all-species effort expended in the depth intervals containing the rank-1 (most) and rank-2 (next-most) landings of that species. Comparison of the new option method with the conventional qualification method indicated that the latter method underestimated expended effort, particularly for less important species. Trends in effort and CPUE did not differ appreciably among methods. The new option method is deemed to be superior to the conventional qualification method.Key words: effort allotment, multispecies trawl fisher, Hecate Strait, western Canada

Review of the Ocalea group of genera (Coleoptera, Staphylinidae, Aleocharinae) in Canada and Alaska: new taxa, bionomics, and distribution

2004 ◽  
Vol 136 (4) ◽  
pp. 443-500 ◽  
Author(s):  
Jan Klimaszewski ◽  
Georges Pelletier
Keyword(s):  
United States ◽  
British Columbia ◽  
Type Species ◽  
First Record ◽  
Yukon Territory ◽  
Western Canada ◽  
Nominal Species ◽  
Mixed Species ◽  
Nomen Novum ◽  
Nearctic Region

AbstractA review of the Nearctic genera and Canadian and Alaskan species of the Ocalea group is presented. Ten genera are treated, with five erected as new: Alfocalea Klimaszewski gen. nov. (type species: A. montana Klimaszewski sp. nov.), Betocalea Klimaszewski gen. nov. (type species: B. pacifica Klimaszewski sp. nov.), Gennadota Casey (reinstated), Longipeltina Bernhauer, Megocalea Klimaszewski gen. nov. (type species: M. lemieuxi Klimaszewski sp. nov.), Metocalea Klimaszewski gen. nov. (type species: M. lindgreni Klimaszewski sp. nov.), Neoisoglossa (Casey) (nomen novum), Neothetalia Klimaszewski gen. nov. (type species: N. nimia (Casey)), Ocalea Erichson (restricted definition), and Parocalea Bernhauer. Twenty-four species of the Ocalea group are here recognized in the Nearctic region, fourteen of which occur in Canada. Six new species are described from western Canada and Alaska: Neothetalia smetanai Klimaszewski sp. nov. (Canada: British Columbia), Neothetalia canadiana Klimaszewski sp. nov. (Canada: British Columbia, Yukon Territory; United States: Alaska), Betocalea pacifica (Canada: British Columbia), Alfocalea montana (Canada: Alberta, British Columbia), Metocalea lindgreni (Canada: British Columbia), and Megocalea lemieuxi (Canada: British Columbia). The first record of Neoisoglossa agnita (Casey) in Alberta is provided. Two nominal species, Atheta (Athetalia) bicarniceps Casey (= Neoisoglossa) and Isoglossa grandicollis (Casey) (= Neoisoglossa), are here synonymized with Neoisoglossa arcuata (Casey). Aleochara pallitarsis Kirby has been transferred to the genus Neothetalia and is newly recorded from Alaska and British Columbia. Ocalea columbiana Klimaszewski has been transferred to Neothetalia and is newly recorded from Alaska. Neothetalia pallitarsis was formerly recorded from an unknown locality in North America and Neothetalia columbiana from the Carmanah Valley on Vancouver Island. Neothetalia nimia is newly recorded from Alaska. A new generic classification is proposed to accommodate species of the Nearctic Ocalea group. New data are provided on the systematics, relationships, bionomics, and distribution of the Nearctic species and genera of America north of Mexico. Diagnoses, colour images of entire bodies, and line illustrations of genital features are provided for those Canadian and Alaskan species that were not formerly illustrated, and their collection localities are plotted on maps. A key to Nearctic genera of the Ocalea group and the species occurring in Canada and Alaska is presented. The lectotypes have been designated for the following nominal species because the original series consisted of syntypes or represented mixed species or both sexes but with males bearing a better diagnostic set of characters: Aleochara picata Stephens (= Ocalea), Atheta (Athetalia) bicarniceps, Atheta (Athetalia) nimia Casey (= Neothetalia), Atheta (Athetalia) repensa Casey (= Neoisoglossa), Isoglossa arcuata Casey (= Neoisoglossa), Ocalea agnita Casey (= Neoisoglossa), Ocalea franciscana Casey (= Neoisoglossa), Ocalea fusca Fenyes (= Neoisoglossa), Ocalea grandicollis Casey (= Neoisoglossa), Pyroglossa grossa Bernhauer, Rheobioma disjuncta Casey (= Neoisoglossa), Rheobioma marcida Casey (= Neoisoglossa), and Rheobioma terrena Casey (= Neoisoglossa).

Numerical Definition of Groundfish Assemblages Caught Off the Coasts of Oregon and Washington Using Commercial Fishing Strategies

1992 ◽  
Vol 49 (12) ◽  
pp. 2648-2656 ◽  
Author(s):  
Jean Beyer Rogers ◽  
Ellen K. Pikitch
Keyword(s):  
Single Species ◽  
The Other ◽  
Commercial Fishing ◽  
Mixed Species ◽  
Important Species ◽  
Trawl Fishery ◽  
Fishing Strategies ◽  
Management Plans ◽  
Recorded Data ◽  
Definition Of

Numerical definition of species caught together by the groundfish trawl fishery operating off the Oregon and Washington coasts during 1985–87 indicated six major assemblages of species. Observers on commercial vessels recorded data allowing estimation of the weights of commercially important species caught in each tow. Assemblages were selected based on consistencies in three types of analysis of the species weights: detrended correspondence ordination, two-way indicator species clustering, and Bray–Curtis group average clustering. Two of the assemblages were dominated by a single species, one consisting largely of smooth pink shrimp (Pandalus jordani) and the other primarily of widow rockfish (Sebastes entomelas). The other assemblages identified were a deepwater rockfish assemblage, a deepwater Dover sole assemblage, a nearshore mixed-species assemblage, and a bottom rockfish assemblage. These assemblages of commercially cooccurring species may be treated as units in developing mixed-species management plans. The deepwater rockfish assemblage we identify has not been previously described.

SEASONAL ACTIVITY OF DUNG BEETLES (COLEOPTERA: SCARABAEIDAE) ASSOCIATED WITH CATTLE DUNG IN SOUTHERN ALBERTA AND THEIR GEOGRAPHIC DISTRIBUTION IN CANADA

1998 ◽  
Vol 130 (2) ◽  
pp. 131-151 ◽  
Author(s):  
K.D. Floate ◽  
B.D. Gill
Keyword(s):  
British Columbia ◽  
Exotic Species ◽  
Geographic Distribution ◽  
Native Species ◽  
Dung Beetles ◽  
Cattle Dung ◽  
Individual Species ◽  
Western Canada ◽  
Seasonal Activity ◽  
Southern Alberta

AbstractDung beetles (Scarabaeidae) were pitfall trapped at two sites in southern Alberta from 1993 to 1995. A 3-year total of 156 500 specimens representing 17 species was collected. Local assemblages were dominated, in descending order, by the exotic species Onthophagus nuchicornis (Linné), Aphodius prodromus (Brahm), Aphodius distinctus (O.F. Müller), and Aphodius fimetarius (Linné). Aphodius vittatus Say was the most common native species. Although adults were collected from mid-March to mid-November, the activity of individual species either peaked in the spring and again in the fall, or peaked once in spring to midsummer. Maps showing the Canadian distributions for 15 of these species were compiled from examination of collections and published records and identify 10 new provincial records. Most distributions are transcontinental, with the distribution of O. nuchicornis likely expanding only in the last 20–30 years to include Alberta and Saskatchewan. Aphodius erraticus (Linné) and Aphodius ruricola Melsheimer have not been previously reported from British Columbia. Aphodius pinguellus W.J. Brown, Canthon praticola LeConte, and Aphodius coloradensis Horn are restricted to western Canada.

Deriving optimal fishing effort for managing Australia's Moreton Bay multispecies trawl fishery with aggregated effort data

2014 ◽  
Vol 72 (5) ◽  
pp. 1278-1284 ◽  
Author(s):  
Na Wang ◽  
You-Gan Wang ◽  
Anthony J. Courtney ◽  
Michael F. O'Neill
Keyword(s):  
Optimal Allocation ◽  
Spatial Information ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Individual Species ◽  
Target Species ◽  
Daily Cost ◽  
Trawl Fishery ◽  
Moreton Bay ◽  
Total Effort

Abstract Deriving an estimate of optimal fishing effort or even an approximate estimate is very valuable for managing fisheries with multiple target species. The most challenging task associated with this is allocating effort to individual species when only the total effort is recorded. Spatial information on the distribution of each species within a fishery can be used to justify the allocations, but often such information is not available. To determine the long-term overall effort required to achieve maximum sustainable yield (MSY) and maximum economic yield (MEY), we consider three methods for allocating effort: (i) optimal allocation, which optimally allocates effort among target species; (ii) fixed proportions, which chooses proportions based on past catch data; and (iii) economic allocation, which splits effort based on the expected catch value of each species. Determining the overall fishing effort required to achieve these management objectives is a maximizing problem subject to constraints due to economic and social considerations. We illustrated the approaches using a case study of the Moreton Bay Prawn Trawl Fishery in Queensland (Australia). The results were consistent across the three methods. Importantly, our analysis demonstrated the optimal total effort was very sensitive to daily fishing costs—the effort ranged from 9500–11 500 to 6000–7000, 4000 and 2500 boat-days, using daily cost estimates of $0, $500, $750, and $950, respectively. The zero daily cost corresponds to the MSY, while a daily cost of $750 most closely represents the actual present fishing cost. Given the recent debate on which costs should be factored into the analyses for deriving MEY, our findings highlight the importance of including an appropriate cost function for practical management advice. The approaches developed here could be applied to other multispecies fisheries where only aggregated fishing effort data are recorded, as the literature on this type of modelling is sparse.

Multispecies spatial assessment models for the British Columbia groundfish trawl fishery

1999 ◽  
Vol 56 (4) ◽  
pp. 601-628 ◽  
Author(s):  
Carl J Walters ◽  
Ramón Bonfil
Keyword(s):  
British Columbia ◽  
Protected Areas ◽  
Gravity Model ◽  
Marine Protected Areas ◽  
Management Strategies ◽  
Fishing Effort ◽  
Catch Per Unit Effort ◽  
Trawl Fishery ◽  
Spatial Redistribution ◽  
Quota Management

A multispecies spatial model is proposed for evaluation of trawl management strategies and tested with data from British Columbia groundfish. Minimum stock sizes are estimated for 16 species using spatial catch per unit effort data; these data indicate that only small proportions of most stocks are exposed to fishing at any time and that exchange rates of fish between the grounds and other habitats are rapid. A gravity model for spatial effort allocation predicts substantial side effects of marine protected areas or discarding of particular species on nontarget species/grounds due to redistribution of fishing effort. Multispecies, multiground delay-difference models are used in conjunction with the gravity model for spatial effort distribution to predict long-term population responses to various regulatory strategies. This simulation suggests that species composition and spatial structure of the fishery are changing slowly due to reduction in abundance of long-lived species, but rapid collapses of target stocks are unlikely due to spatial redistribution of effort in response to local declines. We question whether quota management (individual vessel quotas) can be safely implemented due to extreme uncertainty about current stock sizes and suggest that a better strategy may be to simply denominate fishing rights as individual effort quotas while providing protection for sensitive stocks through carefully placed marine protected areas.

scholarly journals Spore Dispersal by Dothistroma septosporum in Northwest British Columbia

2015 ◽  
Vol 105 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Kennedy Boateng ◽  
Kathy J. Lewis
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Summer Precipitation ◽  
Disease Spread ◽  
Spore Dispersal ◽  
Mixed Species ◽  
Inoculum Sources ◽  
Pine Trees ◽  
Dothistroma Septosporum ◽  
Needle Blight

We studied spore dispersal by Dothistroma septosporum, causal agent of a serious outbreak of red band needle blight in lodgepole pine plantations in northwest British Columbia. Spore abundance was assessed at different distances and heights from inoculum sources and microclimatic factors were recorded during two consecutive years. Conidia were observed on spore traps from June to September during periods of rainfall. It was rare to detect spores more than 2 m away from inoculum sources. The timing and number of conidia dispersed were strongly tied to the climatic variables, particularly rainfall and leaf wetness. Should the trend toward increased spring and summer precipitation in the study area continue, the results suggest that disease spread and intensification will also increase. Increasing the planting distances between lodgepole pine trees through mixed species plantations and overall reduction in use of lodgepole pine for regeneration in wet areas are the best strategies to reduce the spread of the disease and enhance future productivity of plantations in the study area.

scholarly journals Challenging the Stereotypes: Unexpected Features of Sexual Exploitation among Homeless and Street-Involved Boys in Western Canada

2021 ◽  
Vol 18 (11) ◽  
pp. 5898
Author(s):  
Elizabeth M. Saewyc ◽  
Sneha Shankar ◽  
Lindsay A. Pearce ◽  
Annie Smith
Keyword(s):  
British Columbia ◽  
Sexual Exploitation ◽  
Western Canada ◽  
Youth Health

Research about the sexual exploitation of homeless and street-involved boys is limited and often combined with that of girls. As aggregation can distort unique issues among genders which are exploited, this study provides information about the context of exploitation for homeless boys. Boys participated in the anonymous, multi-city British Columbia (BC), Canada Homeless and Street-Involved Youth Health paper surveys of 2006 and 2014. Measures included questions about trading sex for money, shelter, or other consideration; age first exploited; for whom; where they were living when first traded sex; gender of exploiters; and demographics. Analyses, separately for younger/older boys, explored the prevalence, timing of exploitation vs. homelessness, and ANOVAs to evaluate the patterns of the age of first exploitation by the genders of exploiters. Just over one in four boys reported exploitation (n = 132), with a median age of 14–15 in most groups. Most were runaway or homeless before their first exploitation, but 25.5% (2006) and 41% (2014) were living with family. Most boys were exploited by women (78%–85%), with 62%–65% were exclusively exploited by women.

Impact of cultivars and herbicides on weed management in alfalfa

2006 ◽  
Vol 86 (3) ◽  
pp. 875-885 ◽  
Author(s):  
J. R. Moyer ◽  
S. N. Acharya
Keyword(s):  
British Columbia ◽  
Weed Control ◽  
Weed Management ◽  
Forage Quality ◽  
Western Canada ◽  
Downy Brome ◽  
Weed Species ◽  
Standard Type ◽  
Southern Alberta ◽  
Medicago Sativa L

Weeds, especially dandelion (Taraxacum officinale Weber in F.H. Wigg.), tend to infest a forage alfalfa (Medicago sativa L.) stand 2 to 4 yr after establishment. To develop better weed management systems, experiments were conducted at Lethbridge, Alberta, from 1995 to 2002 and Creston, British Columbia, from 1998 to 2001, which included the alfalfa cultivars Beaver (standard type) and AC Blue J (Flemish type) and annual applications of metribuzin and hexazinone. These herbicides are registered for weed control in irrigated alfalfa in Alberta and alfalfa grown for seed. In addition, two sulfonylurea herbicides, metsulfuron and sulfosulfuron, and glyphosate were included. All of the herbicides except glyphosate controlled or suppressed dandelion and mustard family weeds. Metsulfuron at 5 g a.i. ha-1 almost completely controlled dandelion at both locations. However, after metsulfuron application at Lethbridge, dandelion was replaced with an infestation of downy brome, which is unpalatable for cattle. None of the herbicides increased total forage (alfalfa + weed) yield, and in some instances herbicides reduced forage quality by causing a shift from a palatable to an unpalatable weed species. However, it was observed that AC Blue J consistently yielded more than Beaver, and weed biomass was consistently less in the higher-yielding cultivar. AC Blue J was developed primarily for the irrigated area in southern Alberta and for southern British Columbia. Therefore, additional experiments should be conducted to determine which alfalfa cultivars have the greatest ability to compete with weeds in other regions of western Canada. Key words: Alfalfa yield, dandelion, forage quality, weed control

The Caragana Aphid, Acyrthosiphon caraganae (Cholod.) in Western Canada, and its Separation from the Pea Aphid

1962 ◽  
Vol 94 (10) ◽  
pp. 1075-1077 ◽  
Author(s):  
A. G. Robinson ◽  
G. A. Bradley
Keyword(s):  
British Columbia ◽  
North America ◽  
Chemical Control ◽  
Pea Aphid ◽  
Annual Reports ◽  
Western Canada ◽  
Forest Insect ◽  
Disease Survey ◽  
Caragana Arborescens

Except for occasional references in the Annual Reports of the Forest Insect and Disease Survey of infestations of an aphid on caragana (Caragana arborescens Lam.) in Western Canada and a note on chemical control (Bradley, 1952), there is no published record known to the authors of the occurrence of the caragana aphid, Acyrthosiphon caraganae (Cholod.), in North America. MacNay (1953) summarized reports that severe infesrations of aphids, “probably mainly the caragana aphid”, occurred on caragana in 1952 in the East Kootenays of British Columbia, and at several places in Alberta and Saskatchewan. At some localities 100 per cent defoliation was reported.

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