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 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 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).

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 Group IV humpback whales: their status from aerial and landbased surveys off Western Australia, 2005

2020 ◽  
pp. 223-234
Author(s):  
Charles G.M. Paxton ◽  
Sharon l. Hedley ◽  
John l. Bannister
Keyword(s):  
Aerial Survey ◽  
Group Iv ◽  
Humpback Whales ◽  
Reliable Estimate ◽  
Line Transect ◽  
Absolute Abundance ◽  
Density Estimates ◽  
Abundance Estimates ◽  
Short Period ◽  
Land Station

Single platform aerial line transect and land-based surveys of Southern Hemisphere Group IV humpback whales were undertaken to provide absoluteabundance estimates of animals migrating northward along the western Australian coast during June–August 2005. The aerial survey was designedto cover the whole period of northward migration but the resulting estimates from that survey alone could only, at best, provide relative abundanceestimates as it was not possible to estimate g(0), the detection probability along the trackline, from the data. Owing to logistical constraints, theland-based survey was only possible for a much shorter period (two weeks during the expected peak of the migration in mid-July). This paperproposes three methods that utilise these complementary data in different ways to attempt to obtain absolute abundance estimates. The aerial linetransect data were used to estimate relative whale density (for each day), allowing absolute abundance from the land-based survey to be estimatedfor the short period of its duration. In turn, the land-based survey allowed estimation of g(0) for the aerial survey. Absolute estimates of abundancefor the aerial survey were obtained by combining the g(0) estimate with the relative density estimates, summing over the appropriate number ofdays. The most reliable estimate of northward migrating whales passing the land station for the period of the land-based survey only was 4,700(95% CI 2,700–14,000). The most reliable estimate for the number of whales passing through the aerial survey region for the duration of that survey(55 days from June through to August) was 10,300 (95% CI 6,700–24,500). This is a conservative estimate because the duration of the aerial surveywas almost certainly shorter than the period of the migration. Extrapolation beyond the end of this survey was considered unreliable, but abundancefrom the estimated start of the migration to the end of the survey (87 days from mid-April to August) was estimated to be 12,800 (95% CI 7,500–44,600). The estimated number of whales depends crucially on the assumed migration and period of migration. Results for different migrationparameters are also presented. The point estimates of abundance, whilst higher than those from a previous survey in 1999 (when adjusted for surveyduration) are not significantly so. The peak of the whales’ distribution was found at c.90m water depth.

Changes in the abundance of New Zealand fur seals, Arctocephalus forsteri, in Western Australia

2000 ◽  
Vol 27 (2) ◽  
pp. 165 ◽  
Author(s):  
N. J. Gales ◽  
B. Haberley ◽  
P. Collins
Keyword(s):  
New Zealand ◽  
Western Australia ◽  
South Australia ◽  
Rate Of Change ◽  
Population Increase ◽  
Absolute Abundance ◽  
Abundance Estimate ◽  
Fur Seals ◽  
Fur Seal ◽  
Rate Of Increase

New Zealand fur seals, Arctocephalus forsteri, have been increasing in abundance in South Australia for at least the past three decades. A survey of New Zealand fur seals during the 1989/90 breeding season determined that about 20% of the Australian population bred at 16 sites in Western Australia, amounting to 1429 pups and an absolute abundance estimate of 7100 fur seals. A further survey of all fur seal colonies in Western Australia to determine current pup production and abundance estimates, and trends in pup production since the previous survey was undertaken in January 1999. Of the 17 breeding sites now known in Western Australia, 16 were surveyed and pup production had increased at all but one. The rate of change in pup production at the one unsurveyed site (West Island), was estimated as being equivalent to the mean rate of change at other sites. The estimated mean annual, exponential rate of increase (r) for all sites was 0.09, equivalent to a 9.8% annual increase in pup production and an overall increase in pup production in Western Australia of 113.3% between surveys. Total annual pup production has increased to 3090. The estimate of absolute abundance of New Zealand fur seals in Western Australia is now 15 100, in contrast to the 7100 estimated for the 1989/90 season. Mortality of pups at the time of the survey was estimated to be at least 1.3%. It is predicted that New Zealand fur seal populations will continue to increase in Western Australia. This is likely to have important management implications regarding aquaculture and fisheries activities. The increase in fur seal populations appears to be in contrast to populations of Australian sea lions, Neophoca cinerea, for which preliminary data show no evidence for a population increase. It is unknown whether the dynamics affecting these two species are related.

scholarly journals Population estimate and rate of increase of southern right whales Eubalaena australis in southeastern Australia

2020 ◽  
Vol 41 ◽  
pp. 373-383
Author(s):  
K Stamation ◽  
M Watson ◽  
P Moloney ◽  
C Charlton ◽  
J Bannister
Keyword(s):  
South Australia ◽  
Population Estimate ◽  
Abundance Estimate ◽  
Right Whale ◽  
Eubalaena Australis ◽  
Southeastern Australia ◽  
Rate Of Increase ◽  
Right Whales ◽  
Southern Right Whales ◽  
Australian Coastline

In Australian waters, southern right whales Eubalaena australis form 2 genetically distinct populations that have shown contrasting patterns of recovery since whaling ceased: a western population in South Australia and Western Australia and an eastern population in southeastern Australia (Tasmania, Victoria and New South Wales). Here, we provide an abundance estimate derived from a breeding female superpopulation mark-recapture model for the southeastern southern right whale population. The population comprises 268 individuals (68 breeding females) and has increased at a rate of 4.7% per annum between 1996 and 2017. There has been no significant change in the annual abundance of mother-calf pairs sighted at the only calving ground (Logans Beach in Victoria) over the last 3 decades. The total number of southern right whales (i.e. all adults and calves) using the southeastern Australian coastline has increased by 7% since 1985. Unlike the population estimate (which was restricted to breeding females sighted prior to the post-breeding southward migration), this estimate is likely to include transiting whales from the southwestern population. The theoretical population model predicts 19 breeding females at Logans Beach in 2018 and 28 in 2028; the actual number of breeding females, as of 2018, is 14. This study provides the first complete estimate of population size and rate of increase of southern right whales along the southeastern Australian coastline. This knowledge is critical for assessing population status and recovery of southern right whales in Australia. It provides a basis for monitoring persistence and responses of the population to environmental stressors.

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.

scholarly journals Humpback whale abundance south of 60°S from three complete circumpolar sets of surveys

2020 ◽  
pp. 53-69
Author(s):  
T. A. Branch
Keyword(s):  
Ross Sea ◽  
Austral Summer ◽  
Polar Front ◽  
Humpback Whales ◽  
Antarctic Polar Front ◽  
Breeding Ground ◽  
Abundance Estimates ◽  
Rate Of Increase ◽  
Latitudinal Position ◽  
The Antarctic

Austral summer estimates of abundance are obtained for humpback whales (Megaptera novaeangliae) in the Southern Ocean from the IWC’s IDCR and SOWER circumpolar programmes. These surveys have encircled the Antarctic three times: 1978/79–1983/84 (CPI), 1985/86–1990/91 (CPII) and 1991/92–2003/04 (CPIII), criss-crossing strata totalling respectively 64.3%, 79.5% and 99.7% of the open-ocean area south of 60°S. Humpback whales were absent from the Ross Sea, but were sighted in all other regions, and in particularly high densities around the Antarctic Peninsula, in Management Area IV and north of the Ross Sea. Abundance estimates are presented for each CP, for Management Areas, and for assumed summer feeding regions of each Breeding Stock. Abundance estimates are negatively biased because some whales on the trackline are missed and because some humpback whales are outside the survey region. Circumpolar estimates with approximate midpoints of 1980/81, 1987/88 and 1997/98 are 7,100 (CV = 0.36), 10,200 (CV = 0.30) and 41,500 (CV = 0.11). When these are adjusted simply for unsurveyed northern areas, the estimated annual rate of increase is 9.6% (95% CI 5.8–13.4%). All Breeding Stocks are estimated to be increasing but increase rates are significantly greater than zero only for those on the eastern and western coasts of Australia. Given the observed rates of increase, the current total Southern Hemisphere abundance is greater than 55,000, which is similar to the summed northern breeding ground estimates (~60,000 from 1999–2008). Some breeding ground abundance estimates are far greater, and others far lower, than the corresponding IDCR/SOWER estimates, in a pattern apparently related to the latitudinal position of the Antarctic Polar Front.

Biology, Management, and Protection of North American Sturgeon

2002 ◽  
Keyword(s):  
New York ◽  
South Carolina ◽  
Chesapeake Bay ◽  
Hudson River ◽  
Delaware Bay ◽  
Late Nineteenth Century ◽  
Atlantic Sturgeon ◽  
Preparation Methods ◽  
Abundance Estimate ◽  
Abundance Estimates

<em>Abstract.</em>—This paper analyzes historical abundances of spawning stocks of Atlantic sturgeon <em>Acipenser oxyrinchus</em> during the late nineteenth century, when peak United States harvest of Atlantic sturgeon occurred (3,200 metric tons in 1888). The advent of preparation methods for caviar, transportation networks that allowed export of caviar to Europe, improvements in fishing technology, and development of a domestic smoked sturgeon market caused rapid emergence of an Atlantic sturgeon industry after the Civil War. The industry originated and was centered in the Delaware Bay, which supported the most abundant population on the U.S. East Coast. Important fisheries also developed in the Chesapeake Bay, the Carolinas, and Georgia. Caviar was the principal marketable product of the fishery and large females were targeted, resulting in fisheries collapse at the turn of the century. No substantial resurgence of Atlantic sturgeon landings has occurred in the twentieth century. A previous analysis of U.S. Fish Commission catch and effort records for the Delaware Bay fishery provided an estimate of 180,000 females prior to 1890. The Delaware Bay abundance estimate was extrapolated to other states by calculating the mean level of each state’s contribution to U.S. yields during the period 1880–1901. This approach led to abundance estimates of 29,000 for the Southern States (North Carolina, South Carolina, Georgia, Florida), 20,000 for the Chesapeake Bay (Maryland, Virginia), 180,000 for the Delaware Bay, and 6,000 for the Hudson River (New York). Although the approaches used to estimate historical biomass and abundance contain untested assumptions and biases, the dominance of the Delaware Bay population in comparison to others is in part confirmed by the industry that developed there. Given the uncertainty in abundance estimates, conservative benchmarks are proposed of 10,000 females each, for systems that previously supported important fisheries.

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