Physical Sciences and Mathematics Commons^™

Spatial Variation In Rna:Dna Ratios Of Diporeia Spp. In The Great Lakes Region, Daniel J. Ryan, Maria S. Sepúlveda, Thomas F. Nalepa, Tomas O. Höök

United States Department of Commerce: Staff Publications

Over the past two decades, Diporeia in all of the Laurentian Great Lakes, except Superior, have declined dramatically. These declines have seemingly coincided with expansion of invasive Dreissena polymorpha and D. bugensis, however the exact mechanisms underlying decreasing Diporeia densities are obscure. We explored the use of RNA:DNA (R/D) ratios as a conditional index for Diporeia by experimentally demonstrating that Diporeia R/D responds to periods of starvation. Moreover, during 2008–2009 we collected Diporeia from throughout the Great Lakes and Cayuga Lake (New York, USA), and used R/D ratios to index condition of these in situ collected animals. We evaluated …

Chilean Blue Whales As A Case Study To Illustrate Methods To Estimate Abundance And Evaluate Conservation Status Of Rare Species, Rob Williams, Sharon L. Hedley, Trevor A. Branch, Mark B. Bravington, Alexandre N. Zerbini, Ken P. Findlay

United States Department of Commerce: Staff Publications

Often abundance of rare species cannot be estimated with conventional design-based methods, so we illustrate with a population of blue whales ( Balaenoptera musculus) a spatial model-based method to estimate abundance. We analyzed data from line-transect surveys of blue whales off the coast of Chile, where the population was hunted to low levels. Field protocols allowed deviation from planned track lines to collect identification photographs and tissue samples for genetic analyses, which resulted in an ad hoc sampling design with increased effort in areas of higher densities. Thus, we used spatial modeling methods to estimate abundance. Spatial models are increasingly …

Humpback Whale Abundance In The North Pacific Estimated By Photographic Capture-Recapture With Bias Correction From Simulation Studies, Jay Barlow, John Calambokidis, Erin A. Falcone, C. Scott Baker, Alexander M. Burdin, Phillip J. Clapham, John K. B. Ford, Christine M. Gabriele, Richard Leduc, David K. Mattila, Terrance J. Quinn Ii, Lorenzo Rojas-Bracho, Janice M. Straley, Barbara L. Taylor, Jorge Urbán R., Paul Wade, David Weller, Briana H. Witteveen, Manami Yamaguchi

United States Department of Commerce: Staff Publications

We estimated the abundance of humpback whales in the North Pacific by capture recapture methods using over 18,000 fluke identification photographs collected in 2004–2006. Our best estimate of abundance was 21,808 (CV=0.04). We estimated the biases in this value using a simulation model. Births and deaths, which violate the assumption of a closed population, resulted in a bias of +5.2%, exclusion of calves in samples resulted in a bias of−10.5%, failure to achieve random geographic sampling resulted in a bias of −0.4%, and missed matches resulted in a bias of +9.3%. Known sex-biased sampling favoring males in breeding areas did …

Design And Field Methods For Sighting Surveys Of Cetaceans In Coastal And Riverine Habitats, Steve Dawson, Paul Wade, Elisabeth Slooten, Jay Barlow

United States Department of Commerce: Staff Publications

1. Dolphins and porpoises in coastal and/or riverine habitats face serious conservation threats, yet surveys of their abundance are often especially difficult due to the challenges imposed by the habitats. Because many of these species occur in developing countries, lack of resources imposes a further set of challenges.

2. We offer advice on designing and conducting line-transect surveys with a focus on sound, practical, design rather than analytical sophistication, and we attempt, where possible, to offer simple, inexpensive solutions.

3. We guide the reader through the questions of what kind of survey should be done, whether by boat or aircraft, …

Cetacean Abundance In Hawaiian Waters Estimated From A Summer/Fall Survey In 2002, Jay Barlow

United States Department of Commerce: Staff Publications

Cetacean abundance is estimated for the U.S. Exclusive Economic Zone (EEZ) around the Hawaiian Islands based on a ship line-transect survey from August to November, 2002. Sighting detection functions are estimated from this and other NOAA research surveys from 1986 to 2002 using a new, multiple-covariate approach. Twenty-four species were seen on this survey, including two species (Fraser’s dolphin [Lagenodelphis hosei] and sei whale [Balaenoptera borealis]) that had not been previously documented to occur in Hawaiian waters. The most abundant large whales are sperm whales (Physeter macrocephalus) and Bryde’s whales (Balaenoptera edeni). The most …

Estimates Of Sperm Whale Abundance In The Northeastern Temperate Pacific From A Combined Acoustic And Visual Survey, Jay Barlow, Barbara L. Taylor

United States Department of Commerce: Staff Publications

We estimate the abundance of sperm whales in a 7.8 million km² study area in the eastern temperate North Pacific using data from a ship-based acoustic and visual line-transect survey in spring 1997. Sperm whales were detected acoustically using a hydrophone array towed at 15 km/h and 100 m depth. The hydrophone array was towed for 14,500 km, and locations were estimated acoustically for 45 distinct sperm whale groups. Whales producing slow clicks (>2-s period) were detected at greater distance (up to 37 km), and the estimation of effective strip widths was stratified based on initial click period. …

Abundance Of Blue And Humpback Whales In The Eastern North Pacific Estimated By Capture-Recapture And Line-Transect Methods, John Calambokidis, Jay Barlow

United States Department of Commerce: Staff Publications

We estimated humpback and blue whale abundance from 1991 to 1997 off the west coast of the US. 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 4,2 12 identifications of 824 humpback whales and 2,403 identifications of 908 blue whales primarily through non-systematic small-boat surveys along the coast of California, Oregon, and Washington. Line-transect surveys from NOAA ships in 1991, 1993, and 1996 covered approximately 39,000 km along the coast of Baja California, California, Oregon, and Washington out to 555 km from shore. The nearshore and clumped …

Seasonal Patterns In The Abundance And Distribution Of California Cetaceans, 1991-1992, Karin A. Forney, Jay Barlow

United States Department of Commerce: Staff Publications

This study presents a detailed seasonal comparison of the abundance and distribution of cetaceans within 100-150 nmi (185-278 km) of the California coast during 1991 and 1992. The results of a shipboard line-transect survey conducted in July-November 1991 (“summer”) were compared to those from aerial line-transect surveys conducted in March-April 1991 and February-April 1992 (“winter”). Using a confidence-interval-based bootstrap procedure, abundance estimates for six of the eleven species included in the comparison exhibited significant (a = 0.05) differences between the winter and summer surveys. Pacific white-sided dolphins (Lagenorhynchus obliquidens), Risso’s dolphins (Grampus griseus), common dolphins ( …

Distribution And Abundance Of The Amazon River Dolphin (Inia Geoffrensis) And The Tucuxi (Sotalia Fluviatilis) In The Upper Amazon River, Omar Vidal, Jay Barlow, Luis A. Hurtado, Instituto Tecnológico Y De Estudios Superiores De Monterrey (Itesm), Patricia Cendón, Zully Ojeda

United States Department of Commerce: Staff Publications

A boat survey was conducted from 5 to 26 June 1993 to estimate the abundance of the Amazon river dolphin (Inia geoffrensis) and the tucuxi (Sotalia fluviatilis) along ca. 120 km of the Amazon River bordering Colombia, Peru, and Brazil. Two survey methods were used: line transects during 5 d and strip transects during 15 d. The line transects were used to estimate the abundance of both species in the main channels of the Amazon at distances greater than 200 m from river banks and islands, and strip transects were used to estimate abundance in the …

First Estimates Of Vaquita Abundance, Jay Barlow, Tim Gerrodette, Greg Silber

United States Department of Commerce: Staff Publications

The abundance of the only population of vaquitas, Gulf of California harbor porpoise (Phocoena sinus), is estimated from four surveys conducted in Mexico between 1986 and 1993, using a variety of methods. A line-transect approach was applied, using some parameters estimated from a related species, the harbor porpoise (Phocoena phocoena). Vaquita abundance is estimated as 503 (CV = 0.63) from 1986-1988 boat surveys, 885 (CV = 0.50) from 1988-- 1989 aerial surveys, 572 (CV = 1.43) from a 1991 aerial survey, and 224 (CV = 0.39) from a 1993 ship survey. A weighted log-linear regression in …