| loss of genetic diversity in the endemic hector's dolphin due to fisheries-related mortality. | the endemic new zealand hector's dolphin is considered the rarest species of marine dolphin with a total abundance of less than 4000. the species is listed as vulnerable because of fisheries-related mortality due to entanglement in set nets. the vulnerability of this species is further increased by its fidelity to local natal ranges and the genetic isolation of regional populations. here we present evidence, based on 108 contemporary samples and 55 historical samples dating back to 1870, of a si ... | 2000 | 10670959 |
| pcbs and organochlorine pesticides in hector's (cephalorhynchus hectori hectori) and maui's (cephalorhynchus hectori maui) dolphins. | polychlorinated biphenyls (pcbs) and organochlorine (oc) pesticide levels were determined in blubber samples collected from stranded and incidentally by-caught hector's (cephalorhynchus hectori hectori) and maui's (cephalorhynchus hectori maui) dolphins from new zealand waters between 1997 and 2009. pcbs (45 congeners) and a range of oc pesticides including dieldrin, hexachlorocyclohexane (hch) and dichlorodiphenyltrichloroethane (ddt), along with its metabolites dde and ddd were determined. oc ... | 2010 | 20226477 |
| confronting socially generated uncertainty in adaptive management. | as more and more organizations with responsibility for natural resource management adopt adaptive management as the rubric in which they wish to operate, it becomes increasingly important to consider the sources of uncertainty inherent in their endeavors. without recognizing that uncertainty originates both in the natural world and in human undertakings, efforts to manage adaptively at the least will prove frustrating and at the worst will prove damaging to the very natural resources that are th ... | 2010 | 20965642 |
| an atypical genotype of toxoplasma gondii as a cause of mortality in hector's dolphins (cephalorhynchus hectori). | hector's dolphins (cephalorhynchus hectori) are a small endangered coastal species that are endemic to new zealand. anthropogenic factors, particularly accidental capture in fishing nets, are believed to be the biggest threat to survival of this species. the role of infectious disease as a cause of mortality has not previously been well investigated. this study investigates toxoplasma gondii infection in hector's dolphins, finding that 7 of 28 (25%) dolphins examined died due to disseminated tox ... | 2013 | 23207018 |
| trace elements, pcbs and organochlorine pesticides in new zealand common dolphins (delphinus sp.). | trace elements, polychlorinated biphenyls (pcbs) and organochlorine (oc) pesticide levels were determined in tissues collected from stranded and bycaught common dolphins (delphinus sp.) from new zealand waters between 1999 and 2005. the concentrations of mercury (hg), selenium (se), chromium (cr), zinc (zn), nickel (ni), cadmium (cd), cobalt (co), manganese (mn), iron (fe), copper (cu), tin (sn), lead (pb), arsenic (as) and silver (ag) were determined in blubber, liver and kidney tissue. pcbs (4 ... | 2007 | 17644163 |
| origin and radiation of southern hemisphere coastal dolphins (genus cephalorhynchus). | the genus cephalorhynchus (gray 1846) consists of four species of small coastal dolphins distributed in cool temperate waters around the southern hemisphere. each species is sympatric with other members of the subfamily lissodelphininae but widely separated from other congeners. to describe the origin and radiation of these species, we examined 442 bp of mitochondrial dna control region sequences of 307 individuals from the genus cephalorhynchus and compared these to sequences from other members ... | 2001 | 11555263 |
| brucellosis in endangered hector's dolphins (cephalorhynchus hectori). | brucella spp infections of marine mammals are often asymptomatic but have been associated with reproductive losses and deaths. zoonotic infections originating from marine isolates have also been described. hector's dolphins (cephalorhynchus hectori) are an endangered species with a declining population, and the role of infectious disease in population dynamics is not fully understood. in this study, 27 hector's dolphins found dead around the new zealand coastline between november 2006 and octobe ... | 2017 | 28494705 |
| feeding at a high pitch: source parameters of narrow band, high-frequency clicks from echolocating off-shore hourglass dolphins and coastal hector's dolphins. | toothed whales depend on echolocation for orientation and prey localization, and source parameters of echolocation clicks from free-ranging animals therefore convey valuable information about the acoustic physiology and behavioral ecology of the recorded species. recordings of wild hourglass (lagenorhynchus cruciger) and hector's dolphins (cephalorhynchus hectori) were made in the drake passage (between tierra del fuego and the antarctic peninsular) and banks peninsular (akaroa harbour, new zeal ... | 2009 | 19275335 |
| high concentrations of isovaleric acid in the fats of odontocetes: variation and patterns of accumulation in blubber vs. stability in the melon. | isovaleric acid (iso5:0) is an unusual fatty acid that is important for echolocation and hearing in acoustic tissues of some odontocetes, but its functional significance in blubber is unknown. we examined patterns of accumulation of this compound in blubber in 30 species of odontocetes ( n=299). iso5:0 concentrations in blubber varied with phylogeny, ontogeny and body topography. iso5:0 accumulated in greater quantities in superficial/outer blubber than in deep/inner blubber. in the outer blubbe ... | 2003 | 12743728 |
| bayesian inference for small-sample capture-recapture data. | we consider data on the survival of a population of cephalorhynchus hectori, hector's dolphins, in a marine area of new zealand. to estimate survival probabilities of animal populations, a multiple capture-recapture sampling scheme can be used. in this paper, we propose a practical methodology to derive approximations to posterior distributions based on laplace methods. we show how to calculate bayes estimates and credible intervals in this setting. | 1999 | 11314999 |
| a method for testing association patterns of social animals. | association indices were originally developed to describe species co-occurrences, but have been used increasingly to measure associations between individuals. however, no statistical method has been published that allows one to test the extent to which the observed association index values differ from those of a randomly associating population. here, we describe an adaptation of a test developed by manly (1995, ecology, 76, 1109-1115), which uses the observed association data as a basis for a co ... | 1998 | 9784222 |
| intrinsic echolocation capability of hector's dolphin, cephalorhynchus hectori. | a sonar system's echolocation capabilities can be inferred from the ambiguity distribution (defined here in terms of the conventional signal response function) of each of its transmitted signals. several records of sounds emitted by hector's dolphin are analyzed. the computed ambiguity distributions indicate that the sonar clicks of hector's dolphins should be capable of resolving the ranges of targets as close together as 2 cm apart, but that target velocities cannot be resolved to any useful d ... | 1991 | 1787235 |