Cetacean diversity of the continental shelf and slope off southern australia

Gill, Peter C.; Pirzl, Rebecca; Morrice, Margaret G.; Lawton, Kieran

doi:10.1002/jwmg.867

Cited by 15 publications

(9 citation statements)

References 45 publications

(48 reference statements)

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“…g . aerial vs ship-based surveys), species richness (n≥21) was similar to other productive areas worldwide such as the temperate waters of southern Australia (n≥15, [ 4 ]) and the California current system (n = 21, [ 44 ]), the tropical waters of Gulf of Mexico (n = 28, [ 6 ]), the eastern Pacific (n = 30, [ 45 ]) and the cold waters in the Pacific sub-Arctic gyres (n = 24, [ 46 ]). The fact that 90% of the species richness was recorded within the first four cruises indicates that the area was properly surveyed.…”

Section: Discussionmentioning

confidence: 63%

“…Oceanic productive areas are known to aggregate high species richness and abundance of top predators, such as cetaceans, and are usually situated near hydrographic fronts and abrupt topographies which are characterized by strong sea surface temperature gradients and high chlorophyll concentrations [ 1 , 2 , 3 ]. In southern Australia, for example, the most common cetacean species were associated to upwelling season and migration cycles [ 4 ]. In the oceanic waters of Gulf of Mexico species appeared to concentrate near the slope or around eddies, where the amount of potential prey for cetaceans may be consistently greater in some seasons [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

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Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope

et al. 2016

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Temporal and spatial patterns of cetacean diversity and distribution were investigated through eight ship-based surveys carried out during spring and autumn between 2009 and 2014 on the outer continental shelf (~150m) and slope (1500m) off southeastern and southern Brazil (~23°S to ~34°S). The survey area was divided into southeast and south areas according to their oceanographic characteristics. Twenty-one species were observed in 503 sightings. The overall number of species was similar between the two areas, though it was higher in the spring in the south area. Five species were dominant and diversity varied more seasonally than spatially. ANOVA and kernel analyses showed that overall cetacean densities were higher in spring compared to autumn. Physeter macrocephalus, the most frequent species, concentrated throughout the south area at depths over 1000m in both seasons. Despite the overlapped occurrence at a broader scale, small delphinids presented latitudinal and in-offshore gradients as well as seasonal variation in distribution patterns, which could indicate habitat partitioning between some species. Delphinus delphis was only recorded in the south and its density decreased in areas where the presence of Stenella frontalis increased, mainly beyond the 250m isobath. Densities of S. longirostris and S. attenuata increased in lower latitudes and beyond the shelf break. The large delphinids Tursiops truncatus and Globicephala melas formed mixed groups in many occasions and were observed along the study area around depths of 500m. Grampus griseus was twice as frequent in the south area and densities increased in waters deeper than 600m. As expected, densities of both small and large migratory whales were higher during spring, over the continental slope, in the southeast area. The results presented here provided strong evidence on the importance of the outer continental shelf and slope to a diverse community of cetaceans occurring in the subtropical Southwestern Atlantic.

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Section: Discussionmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope

et al. 2016

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“…A number of marine mammal species are known to take advantage of this convergence, which is associated with areas of high primary productivity. Sightings surveys off the coast of south Australia have detected several beaked whales (Gill et al, 2015) with one particular sighting involving a single group of 20 unidentified mesoplodonts largely fitting the description of Gray's beaked whales (P. Gill, pers. comm.).…”

Section: Discussionmentioning

confidence: 70%

Bucking the trend: genetic analysis reveals high diversity, large population size and low differentiation in a deep ocean cetacean

et al. 2015

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Understanding the genetic structure of a population is essential to its conservation and management. We report the level of genetic diversity and determine the population structure of a cryptic deep ocean cetacean, the Gray's beaked whale (Mesoplodon grayi). We analysed 530 bp of mitochondrial control region and 12 microsatellite loci from 94 individuals stranded around New Zealand and Australia. The samples cover a large area of the species distribution (~6000 km) and were collected over a 22-year period. We show high genetic diversity (h = 0.933-0.987, π = 0.763-0.996% and R s = 4.22-4.37, H e = 0.624-0.675), and, in contrast to other cetaceans, we found a complete lack of genetic structure in both maternally and biparentally inherited markers. The oceanic habitats around New Zealand are diverse with extremely deep waters, seamounts and submarine canyons that are suitable for Gray's beaked whales and their prey. We propose that the abundance of this rich habitat has promoted genetic homogeneity in this species. Furthermore, it has been suggested that the lack of beaked whale sightings is the result of their low abundance, but this is in contrast to our estimates of female effective population size based on mitochondrial data. In conclusion, the high diversity and lack of genetic structure can be explained by a historically large population size, in combination with no known exploitation, few apparent behavioural barriers and abundant habitat.

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“…Other than observational effort, the oceanographic characteristics of an area are often attributed to the differences observed in cetacean distribution and diversity [44, 45]. In this study the OTW region demonstrated the highest diversity and the highest stranding rate of cetaceans along the open ocean coastal regions.…”

Section: Discussionmentioning

confidence: 73%

Cetacean biodiversity, spatial and temporal trends based on stranding records (1920-2016), Victoria, Australia

Foord¹,

Rowe

Robb³

2019

PLoS ONE

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Cetacean stranding records can provide vital information on species richness and diversity through space and time. Here we collate stranding records from Victoria, Australia and assess them for temporal, spatial and demographic trends. Between 1920 and 2016, 424 stranding events involving 907 individuals were recorded across 31 Cetacea species from seven families, including five new species records for the state. Seven of these events were mass strandings, and six mother and calf strandings were recorded. Importantly, 48% of the species recorded are recognised as data deficient on the IUCN Red List. The most commonly recorded taxa were Tursiops spp. (n = 146) and Delphinus delphis (common dolphins, n = 81), with the greatest taxonomic richness (n = 24) and highest incidence of stranding events documented within the Otways mesoscale bioregion. We found no seasonal stranding patterns anywhere in the state. While our findings improve understanding of the spatial and temporal patterns of cetacean diversity within Victoria, we suggest greater effort to collect demographic data at stranding events in order to better study state-wide patterns through time. We conclude with guidelines for minimum data collection standards for future strandings to maximise information capture from each event.

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Cetacean diversity of the continental shelf and slope off southern australia

Cited by 15 publications

References 45 publications

Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope

Diversity and Distribution Patterns of Cetaceans in the Subtropical Southwestern Atlantic Outer Continental Shelf and Slope

Bucking the trend: genetic analysis reveals high diversity, large population size and low differentiation in a deep ocean cetacean

Cetacean biodiversity, spatial and temporal trends based on stranding records (1920-2016), Victoria, Australia

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