We estimated humpback and blue whale abundance from 1991 to 1997 off the west coast of the U.S. and Mexico comparing capture-recapture models based on photographically identified animals and line-transect methods from ship-based surveys. During photo-identification research we obtained 4,212 identifications of 824 humpback whales and 2,403 identifications of 908 blue whales primarily through no...

The conventional line transect approach of estimating effective search width from the perpendicular distance distribution is inappropriate in certain types of surveys, e.g., when an unknown fraction of the animals on the track line is detected, the animals can be observed only at discrete points in time, there are errors in positional measurements, and covariate heterogeneity exists in detectab...

Systematic aerial line-transect surveys of beluga whales, Delphinapterus leucas, were conducted in James Bay, eastern Hudson Bay, and Ungava Bay from 14 August to 3 September 2001. An estimated 7901 (SE = 1744) and 1155 (SE = 507) belugas were present at the surface in the offshore areas of James Bay and Hudson Bay, respectively. An additional 39 animals were observed in estuaries during the co...

Nacrtak Assessment of disturbance can provide forest managers with information to make appropriate decisions on site rehabilitation and monitoring. This paper evaluates the accuracy of successive estimates of site disturbance using two ground survey methods. The results from the point transect and grid point transect and grid point intercept methods were compared with the results from an intens...

The effects of the colonization of an abandoned grassland by forest trees and the associated microenvironmental changes on soil properties and the microbial activity of soil were studied along a 170 m transect established on a former pasture colonized by Norway spruce (Picea abies Karst.) in Central Slovakia. The transect with a 5×5 m grid of sampling points crosses all successional stages from...

Marine debris is one of the environmental problems in Indonesia's coastal and marine areas, especially macroplastics. One areas with macroplastic tourist beach, which may adversely affect ecosystem, biota, reduce quality environment. The purpose this study was to identify type composition, calculate total weight, determine difference density two different periods. This conducted March August 20...

The responses of pine forest to changing climate and environmental chemistry were studied along two transects following the pollution and continentality gradients in Poland. One axis begins on the western border of Poland, crosses the country along the 52nd parallel, and ends on the eastern border of Poland in the area of Bialowieza National Park, Biosphere Reserve. The second axis begins in in...

—The North American Breeding Bird Survey (BBS) is an annual transect point-count survey of >500 species and >3,500 survey routes (transects). Observers drive and record birds seen and heard within a radius of 400 m of 50 survey points (“stops”) evenly spaced along a 39.4-km survey route. Thus, the land area along both sides of a route composes a linear or curvilinear landscape. Although BBS dat...

Cox's method depends on tallying observed distances within f ixed intervals away from the transect line. Thus all of the observations within a dis tance,∆ , on either side of the line are added up and used to estimate the t r u e proportion of all observations, denoted p(0,∆ ), that fall in that interval. H e n c e if there are k1 observations within the distance ∆ , we estimate p(0,∆ ) = k 1 /...