scholarly journals Abundance of East coast Australian humpback whales (Megaptera novaeangliae) in 2005 estimated using multi-point sampling and capture-recapture analysis

2020 ◽  
pp. 253-259
Author(s):  
David A. Paton ◽  
Lyndon Brooks ◽  
Daniel Burns ◽  
Trish Franklin ◽  
Wally Franklin ◽  
...  
Keyword(s):  
East Coast ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Migration Route ◽  
Closed Population ◽  
Breeding Stock ◽  
Abundance Estimate ◽  
Abundance Estimates ◽  
Capture Recapture ◽  
Near Extinction

The humpback whales (Megaptera novaeangliae) that migrate along the east coast of Australia were hunted to near extinction during the lastcentury. This remnant population is part of Breeding Stock E. Previous abundance estimates for the east Australian portion of Breeding Stock Ehave been based mainly on land-based counts. Here we present a capture-recapture abundance estimate for this population using photo-identificationdata. These data were collected at three locations on the migration route (Byron Bay – northern migration, Hervey Bay and Ballina – southernmigration) in order to estimate the population of humpback whales that migrated along the east coast of Australia in 2005. The capture-recapturedata were analysed using a variety of closed population models with a model-averaged estimate of 7,041 (95% CI 4,075–10,008) whales.

scholarly journals Absolute and relative abundance estimates of Australian east coast humpback whales (Megaptera novaeangliae)

2020 ◽  
pp. 243-252
Author(s):  
Michael J. Noad ◽  
Rebecca A. Dunlop ◽  
David Paton ◽  
Douglas H. Cato
Keyword(s):  
Data Analysis ◽  
East Coast ◽  
Humpback Whales ◽  
Absolute Abundance ◽  
Abundance Estimate ◽  
Abundance Estimates ◽  
Rate Of Increase ◽  
Migratory Population ◽  
Australian Coastline ◽  
Near Extinction

The humpback whales that migrate along the east coast of Australia were hunted to near-extinction in the 1950s and early 1960s. Two independentseries of land-based surveys conducted over the last 25 years during the whales’ northward migration along the Australian coastline havedemonstrated a rapid increase in the size of the population. In 2004 we conducted a survey of the migratory population as a continuation of theseseries of surveys. Two methods of data analysis were used in line with the previous surveys, both for calculation of absolute and relative abundance.We consider the best estimates for 2004 to be 7,090±660 (95% CI) whales with an annual rate of increase of 10.6±0.5% (95% CI) for 1987–2004.The rate of increase agrees with those previously obtained for this population and demonstrates the continuation of a strong post-exploitationrecovery. While there are still some uncertainties concerning the absolute abundance estimate and structure of this population, the rate of annualincrease should be independent of these and highly robust.

scholarly journals Population growth of Australian East coast humpback whales, observed from Cape Byron, 1998 to 2004

2020 ◽  
pp. 261-268
Author(s):  
David A. Paton ◽  
Rric Kniest
Keyword(s):  
Population Growth ◽  
Confidence Intervals ◽  
East Coast ◽  
Megaptera Novaeangliae ◽  
Annual Rate ◽  
Humpback Whales ◽  
Survey Period ◽  
Group V ◽  
Breeding Stock ◽  
Rate Of Increase

Humpback whales (Megaptera novaeangliae) that migrate past the east coast of Australia comprise part of Group V (E(i) breeding stock). From1995 to 2004 an annual 16 day survey was conducted from Cape Byron (28°37’S, 153°38’E), the most easterly point on the Australian mainland,monitoring the peak of the humpback whale northern migration. The annual rate of increase between 1998 and 2004 of humpback whales observedoff Cape Byron is 11.0% (95% CI 2.3–20.5%). This rate of increase is consistent with that recorded from other studies of the humpback whalepopulation off the east coast of Australia. The large confidence intervals associated with this estimate are due to considerable inter-annual variationin counts. The most likely explanation for this being the short survey period, which may not have always coincided with the peak of migration, andin some years a large proportion of whales passed Cape Byron at a greater distance out to sea, making sightability more difficult.

scholarly journals Abundance estimates of Southern Hemisphere Breeding Stock ‘D’ humpback whales from aerial and land-based surveys off Shark Bay, Western Australia, 2008

2020 ◽  
pp. 209-221
Author(s):  
Sharon L. Hedley ◽  
John L. Bannister ◽  
Rebecca A. Dunlop
Keyword(s):  
Southern Hemisphere ◽  
Western Australia ◽  
Aerial Survey ◽  
Humpback Whales ◽  
Line Transect ◽  
Breeding Stock ◽  
Abundance Estimate ◽  
Shark Bay ◽  
Abundance Estimates ◽  
Rate Of Increase

Single platform aerial line transect and land-based surveys of Southern Hemisphere Breeding Stock ‘D’ humpback whales Megaptera novaeangliaewere undertaken off Shark Bay, Western Australia to provide absolute abundance estimates of animals migrating northward along the westernAustralian coast. The aerial survey flew a total of 28 flights, of which 26 were completed successfully, from 24 June–19 August 2008. The landbased survey was undertaken from Cape Inscription, Dirk Hartog Island, Shark Bay, during the expected peak of the whales’ northward migration,from 8–20 July. During the first week of the land-based survey, some double count effort was undertaken to provide information on the numbersof pods missed from the land station. The assumed period of northward migration was 2 June–7 September. Estimated abundance of northwardmigrating whales during that time is 34,290 (95% CI: (27,340–53,350)), representing an annual rate of increase of 12.9% (CV = 0.20) since anestimate of 11,500 in 1999. This estimate is based on an estimate of relative abundance of surface-available whales of 10,840 (8,640–16,860), andan estimated g(0) of 0.32. There were considerable practical difficulties encountered during the land-based survey which reduced the effectivenessof the dual-survey approach for estimating g(0) for the aerial survey. Furthermore only about 15% of whales were estimated to be within the visualrange of the land-based station. Alternative approaches for estimating g(0) from these data are therefore also presented, resulting in considerablyhigher estimates of around 0.6–0.7, and yielding a conservative abundance estimate of 17,810 (14,210–27,720).

Errors in identification using natural markings: rates, sources, and effects on capture–recapture estimates of abundance

2001 ◽  
Vol 58 (9) ◽  
pp. 1861-1870 ◽  
Author(s):  
Peter T Stevick ◽  
Per J Palsbøll ◽  
Tim D Smith ◽  
Mark V Bravington ◽  
Philip S Hammond
Keyword(s):  
Error Rate ◽  
Large Scale ◽  
False Negative ◽  
Parametric Bootstrap ◽  
Humpback Whales ◽  
The North ◽  
Abundance Estimates ◽  
Capture Recapture ◽  
Quality Rating ◽  
Estimation Of Variance

The results of a double-marking experiment using natural markings and microsatellite genetic markers to identify humpback whales (Megaptera novaeangliae) confirm that natural markings are a reliable means of identifying individuals on a large scale. Of 1410 instances of double tagging, there were 414 resightings. No false positive and 14 false negative errors were identified. The rate of error increased with decreasing photographic quality; no errors were observed among photographs of the highest quality rating, whereas an error rate of 0.125 was identified in sightings for which only part of the area used for identification was visible. There was also a weaker relationship between error rate and the distinctiveness of markings, which may result from non-independence in coding for image quality and distinctiveness. A correction is developed for the Petersen two-sample abundance estimator to account for false negative errors in identification, and a parametric bootstrap procedure for estimation of variance is also developed. In application to abundance estimates from the North Atlantic, the correction reduces the bias in estimates made using poorer quality photographs to a negligible level while maintaining comparable precision.

scholarly journals A spatially explicit approach for estimating space use and density of common genets

2014 ◽  
Vol 37 (1) ◽  
pp. 23-33
Author(s):  
P. Sarmento ◽  
◽  
J. Cruz ◽  
C. Eira ◽  
C. Fonseca ◽  
...  
Keyword(s):  
Spatial Model ◽  
Environmental Variables ◽  
Camera Trap ◽  
Grid Size ◽  
Future Research ◽  
Spatially Explicit ◽  
Density Estimates ◽  
Closed Population ◽  
Abundance Estimates ◽  
Capture Recapture

Many species that occur at low densities are not accurately estimated using capture–recapture methods as such techniques assume that populations are well–defined in space. To solve this bias, spatially explicit capture–recapture (SECR) models have recently been developed. These models incorporate movement and can identify areas where it is more likely for individuals to concentrate their activity. In this study, we used data from camera–trap surveys of common genets (Genetta genetta) in Serra da Malcata (Portugal), designed to compare abundance estimates produced by SECR models with traditional closed–capture models. Using the SECR models, we observed spatial heterogeneity in genet distribution and density estimates were approximately two times lower than those obtained from the closed population models. The non–spatial model estimates were constrained to sampling grid size and likely underestimated movements, thereby overestimating density. Future research should consider the incorporation of cost–weighed models that can include explicit hypothesis on how environmental variables influence the distance metric.

Bayesian estimation of humpback whale (Megaptera novaeangliae) population abundance and movement patterns in southeastern Alaska

2012 ◽  
Vol 69 (11) ◽  
pp. 1783-1797 ◽  
Author(s):  
A.N. Hendrix ◽  
J. Straley ◽  
C.M. Gabriele ◽  
S.M. Gende
Keyword(s):  
Deviance Information Criterion ◽  
Information Criterion ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Observation Error ◽  
Movement Model ◽  
Abundance Estimate ◽  
High Area ◽  
Rate Of Increase ◽  
Competing Models

We used a mechanistic movement model within a Bayesian framework to estimate survival, abundance, and rate of increase for a population of humpback whales ( Megaptera novaeangliae ) subject to a long-term photographic capture–recapture effort in southeastern Alaska, USA (SEAK). Multiple competing models were fitted that differed in movement, recapture rates, and observation error using deviance information criterion. The median annual survival probability in the selected model was 0.996 (95% central probability interval (CrI): 0.984, 0.999), which is among the highest reported for this species. Movement among areas was temporally dynamic, although whales exhibited high area fidelity (probability of returning to same area of ≥0.75) throughout the study. Median abundance was 1585 whales in 2008 (95% CrI: 1455, 1644). Incorporating an abundance estimate of 393 (95% confidence interval: 331, 455) whales from 1986, the median rate of increase was 5.1% (95% CrI: 4.4%, 5.9%). Although applied here to cetaceans in SEAK, the framework provides a flexible approach for estimating mortality and movement in populations that move among sampling areas.

Fluctuating abundance of humpback whales (Megaptera novaeangliae) in a calving ground off coastal Brazil

2008 ◽  
Vol 88 (6) ◽  
pp. 1229-1235 ◽  
Author(s):  
Maria E. Morete ◽  
Tatiana L. Bisi ◽  
Richard M. Pace ◽  
Sergio Rosso
Keyword(s):  
Generalized Linear Models ◽  
Count Data ◽  
Linear Models ◽  
East Coast ◽  
General Pattern ◽  
Time Of Day ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Breeding Ground ◽  
Increasing Trend

The humpback whale (Megaptera novaeangliae) population that uses Abrolhos Bank, off the east coast of Brazil as a breeding ground is increasing. To describe temporal changes in the relative abundance of humpback whales around Abrolhos, seven years (1998–2004) of whale count data were collected during July through to November. During one-hour-scans, observers determined group size within 9.3 km (5 n.m.) of a land-based observing station. A total of 930 scans, comprising 7996 sightings of adults and 2044 calves were analysed using generalized linear models that included variables for time of day, day of the season, years and two-way interactions as possible predictors. The pattern observed was the gradual build-up and decline in whale counts within seasons. Patterns and peaks of adult and calf counts varied among years. Although fluctuation was observed, there was generally an increasing trend in adult counts among years. Calf counts increased only in 2004. These fluctuations may have been caused by some environmental conditions in humpback whales' summering grounds and also by changes in spatial–temporal concentrations in Abrolhos Bank. The general pattern observed within the study area mirrored what was observed in the whole Abrolhos Bank. Knowledge of the consistency with which humpback whales use this important nursing area should prove beneficial for designing future monitoring programmes especially related to whale watching activities around Abrolhos Archipelago.

Local and migratory movements of Hawaiian humpback whales tracked by satellite telemetry

1998 ◽  
Vol 76 (5) ◽  
pp. 863-868 ◽  
Author(s):  
Bruce R Mate ◽  
Robert Gisiner ◽  
Joseph Mobley
Keyword(s):  
Satellite Telemetry ◽  
Gulf Of Alaska ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Migration Route ◽  
Screening Criteria ◽  
Average Speed ◽  
Migratory Movements ◽  
Magnetic North ◽  
Travel Distances

We examined inter-island movements and offshore migrations of six humpback whales (Megaptera novaeangliae) tagged during March and April 1995 with satellite-monitored radio tags off Kaua´i, Hawai´i. The tags transmitted 0.5-17 days ( x bar = 8.5 ± 2.7 days) and produced 1-66 locations that met our screening criteria. Total travel distances per individual ranged from 30 to 1860 km. After screening criteria were applied, satellite-acquired locations ranged from 1.8 to 3.9/day for individuals (group average 2.7/day). One adult traveled 250 km to O´ahu in 4 days. Another visited Penguin Bank and five islands (820 km) in 10 days, suggesting faster inter-island movement than had been previously thought. Three whales traveled independent, parallel courses toward the upper Gulf of Alaska on north-northeast headings. A female with a calf was the fastest: 670 km in 4.5 days (150 km/day). Two whales traveled for 14.7 and 17 days, an average speed of 110 km/day (4.5 km/h). A 4200-km migration to the upper Gulf of Alaska at that speed would take 39 days. If the fastest whale's speed was maintained on a straight course, the entire migration could be accomplished in as little time as 28 days. Based on the two longest tracks, the first third of the migration route is within 1° of magnetic north. These data represent the first route and travel speeds for humpbacks migrating from Hawai´i toward Alaska.

scholarly journals Abundance estimates and trends for humpback whales (Megaptera novaeangliae) in Antarctic Areas IV and V based on JARPA sightings data

2020 ◽  
pp. 75-94
Author(s):  
Koji Matsuoka ◽  
Takashi Hakamada ◽  
Hiroshi Kiwada ◽  
Hiroto Murase ◽  
Shigetoshi Nishiwaki
Keyword(s):  
Selection Criterion ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Base Case ◽  
Line Transect ◽  
Point Estimates ◽  
Abundance Estimates ◽  
Eastern Australia ◽  
The Antarctic ◽  
Additional Variance

Sighting survey data from the Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) are analysed to obtain abundanceestimates for humpback whales (Megaptera novaeangliae) south of 60°S. The surveys were conducted during the 1989/90–2004/05 austral summerseasons (mainly in January and February); the survey areas alternated between Area IV (70°E–130°E) and Area V (130°E to 170°W) each year.Primary sighting effort totalled 293,811 n.miles over 6,188 days. Abundance estimates are obtained using standard line transect analysis methodsand the program DISTANCE. Estimated densities of humpback whales were highest east of the Kerguelen Plateau (80°E–120°E). Abundanceestimates for Area IV range from 2,747 (CV = 0.153) in 1993/94 to 31,134 (CV = 0.123) in 2001/02, while those for Area V range from 602 (CV= 0.343) in 1990/91 to 9,342 (CV = 0.337) in 2004/05. The estimates are similar to those obtained from the International Whaling Commission’sIDCR-SOWER surveys, which were conducted in Area IV (in 1978/79, 1988/89 and 1998/99) and in Area V (in 1980/81, 1991/92 and 2001/02–2003/04). Estimated annual rates of increase for Area IV (16.4%; 95% CI = 9.5–23.3%) and Area V (12.1%; 95% CI = 1.7–22.6%) are also similarto those obtained from the IDCR-SOWER surveys. The total abundance in Areas IV and V based on the most recent JARPA surveys (2003/04 and2004/05 combined) is 37,125 (95% CI = 21,349–64,558); the confidence interval incorporates estimated additional variance. Results of severalsensitivity tests are presented that suggest that estimates of abundance and trends are not appreciably affected by factors such as different approachesto deal with survey coverage (which in some cases was poor or included gaps). Changes in the order in which survey strata were covered andpotential effects are investigated using a nested GLM approach; a QAIC model selection criterion suggests a preference for not attempting to adjustfor such changes. Under various sensitivity approaches, the point estimates of increase rates are not greatly affected for Area IV. Although theydrop by typically a half for most approaches for Area V, they nevertheless remain within the confidence limits of the base case estimate of 12.1%per year (95% CI = 1.7–22.6%). The presented results thus suggest that the estimated abundance of humpback whales in Area IV has increasedrapidly. Although there is also an increase indicated for Area V, it is neither as rapid nor as precisely estimated. Taking these results together withthe similar rates of increase estimated from coastal surveys off western and eastern Australia for Breeding Stocks D and E respectively, and givendemographic limitations on the increase rates possible for closed populations of humpback whales, the hypothesis is advanced that whales fromBreeding Stock E may have shifted their feeding distribution westward as their numbers have increased, perhaps to take advantage of the higherdensities of krill to be found to the west.

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