Comparison of odontocete populations of the Marquesas and Society Islands (French Polynesia)

2008 ◽  
Vol 89 (5) ◽  
pp. 931-941 ◽  
Author(s):  
Alexandre Gannier
Keyword(s):  
Relative Abundance ◽  
Bottlenose Dolphin ◽  
Bottlenose Dolphins ◽  
Sperm Whale ◽  
French Polynesia ◽  
Society Islands ◽  
Spotted Dolphin ◽  
Abundance Indices ◽  
Beaked Whales ◽  
Using Data

Small boat surveys were organized to study cetaceans of the Marquesas (9°S and 140°W) and the Society Islands (17°S and 150°W) in French Polynesia. Prospecting took place from 12–15 m sailboats, between 1996 and 2001 with systematic visual searching. Boats moved according to sea conditions, at a mean speed of 10 km/h. Effective effort of 4856 km in the Marquesas and 10,127 km in the Societies were logged. Relative abundance indices were processed for odontocetes using data obtained with Beaufort 4 or less. In the Marquesas, 153 on-effort sightings were obtained on 10 delphinids species including the spotted dolphin, spinner dolphin, bottlenose dolphin, melon-headed whale and rough-toothed dolphin. In the Societies, 153 sightings of 12 odontocetes included delphinids (spinner, rough-toothed and bottlenose dolphins, short-finned pilot and melon-headed whales, Fraser's dolphin, Risso's dolphin and pygmy killer whale) and two species of beaked whales, the sperm whale and dwarf sperm whale. Relative abundance indices were higher in the Marquesas than in the Societies both inshore (0.93 ind/km2 against 0.36 ind/km2) and offshore (0.28 ind/km2 against 0.14 ind/km2). Differences in remote-sensed primary production were equally important, the Marquesas waters featuring an annual average of 409 mgC.m−2 · day−1 and the Societies of only 171 mgC · m−2 · day−1. The presence of a narrow shelf around the Marquesas also accounted for differences in odontocete populations, in particular the delphinids.

scholarly journals Observations of cetaceans off southern Sri Lanka, April 2007–2013

2019 ◽  
Vol 20 (1) ◽  
pp. 13-25
Author(s):  
R. C. Anderson ◽  
A. Alagiyawadu
Keyword(s):  
Sri Lanka ◽  
Bottlenose Dolphin ◽  
Sperm Whale ◽  
Abundant Species ◽  
Sperm Whales ◽  
Spotted Dolphin ◽  
Common Bottlenose Dolphin ◽  
Westward Movement ◽  
Number Of Individuals ◽  
Blue Whales

Cetaceans were observed off the South coast of Sri Lanka in the month of April, every year over a seven-year period, 2007–13. During 48 days atsea a total of 290 cetacean sightings were recorded. Blue whales were abundant, accounting for 61% (n = 177) of all sightings. This concentrationof blue whales was predicted and discovered based on a migration hypothesis and there was evidence of the expected net westward movement inApril. Nevertheless, most blue whales seen were not obviously on passage and many appeared to be feeding. Mothers with calves and likelyreproductive behaviour (breaching and rushing) were also observed. There were five sightings of Bryde’s-type whales (B. brydei/edeni); four wereidentified as B. brydei, one was identified as B. edeni. Sperm whales were sighted 16 times within a narrow band centred just outside the 1,000misobath. Modal group size was 10–12; based on size most individuals appeared to be mature females or immatures. Spinner dolphin (n = 35 sightings)was the most abundant species, accounting for 67% of all cetaceans seen by number of individuals. They were frequently associated with tuna andseabirds. Risso’s dolphin was only seen once, despite being reported as common around Sri Lanka in the early 1980s. They were taken in largenumbers by local fisheries, which may have reduced local abundance. Other species recorded were: dwarf sperm whale (n = 3 sightings); shortfinnedpilot whale (n = 3); common bottlenose dolphin (n = 9); Indo-Pacific bottlenose dolphin (n = 3); pantropical spotted dolphin (n = 4); andstriped dolphin (n = 4). Since the discovery of blue whales off southern Sri Lanka, commercial whale watching centred on the fishing port of Mirissahas developed rapidly, bringing new revenue to the region but also the potential for disturbance to the whales.

Seasonal variation of striped dolphins, fin- and sperm whales' abundance in the Ligurian Sea (Mediterranean Sea)

2007 ◽  
Vol 87 (1) ◽  
pp. 345-352 ◽  
Author(s):  
Sophie Laran ◽  
Violaine Drouot-Dulau
Keyword(s):  
Relative Abundance ◽  
Sperm Whale ◽  
Line Transect ◽  
Physeter Macrocephalus ◽  
Monthly Basis ◽  
Ligurian Sea ◽  
Stenella Coeruleoalba ◽  
Abundance Indices ◽  
Fin Whales ◽  
Acoustic Sampling

In order to investigate seasonal changes in cetacean relative abundance, a series of surveys were conducted between the French mainland and Corsica. From February 2001 to February 2004, thirty similar transects were conducted monthly, using the same dedicated boat and a consistent sampling protocol, including visual observation and passive acoustic sampling. A total effort of 5759 km was sampled, conducted at the same speed and in good sighting conditions. Relative abundances of striped dolphins (Stenella coeruleoalba) and fin whales (Balaenoptera physalus) were determined using standard line-transect methodology. The relative abundance of striped dolphins peaked in May and September (>1.3×10-2 ind.km-1), while a consistent minimum value (<0.6×10-2 ind.km-1) was obtained from December to April. A maximum relative abundance of fin whales occurred in August with 5.6×10-2 ind.km-1 and decreased to almost zero from November to January. For sperm whale (Physeter macrocephalus), a long diver species, frequency and abundance indices were determined using acoustic sampling. The highest acoustic relative abundance was observed from August to October, with more than 2×10-2 ind.km-1. Environmental parameters (sea surface temperature and chlorophyll) were computed for the sampling area from remote sensing imagery and pooled on a monthly basis, to correlate with relative abundance indices of the three species.

scholarly journals Prevalencia y abundancia relativa de balanos Xenobalanus globicipitis presentes en poblaciones de delfín nariz de botella Tursiops truncatus en el Golfo de México Sur

2020 ◽  
Vol 55 (2) ◽  
pp. 172
Author(s):  
Imelda Gómez-Hernández ◽  
Arturo Serrano ◽  
Cecilia Becerril-Gómez ◽  
Agustín Basañez-Muñoz ◽  
Celina Naval-Ávila
Keyword(s):  
Gulf Of Mexico ◽  
Relative Abundance ◽  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Dry Season ◽  
Winter Storm ◽  
Host Interaction ◽  
Xenobalanus Globicipitis

Xenobalanus globicipitis is a commensal barnacle located on cetacean fin edges. The commensal-host interaction between Xenobalanus globicipitis and the bottlenose dolphin (Tursiops truncatus) has been poorly studied in Mexico. The main objective was to estimate the relative barnacle prevalence and abundance in bottlenose dolphins in three areas and seasons of the Gulf of Mexico. Tamiahua zone showed the higher prevalence (42.4%) and relative abundance (0.60 barnacles/individual/hr-1)compared to Tuxpan and Nautla zones. Whereas, in dry season there were higher prevalence (55.6%) and relative abundance (0.53 barnacles/individual/hr-1)than rainy and winter storm seasons. Therefore, zones and seasons of the Gulf of Mexico influence the barnacle-dolphin interactions.

scholarly journals Malignant Seminoma with Metastasis, Sertoli Cell Tumor, and Pheochromocytoma in a Spotted Dolphin (Stenella frontalis) and Malignant Seminoma with Metastasis in a Bottlenose Dolphin (Tursiops truncatus)

2005 ◽  
Vol 42 (3) ◽  
pp. 357-359 ◽  
Author(s):  
J. S. Estep ◽  
R. E. Baumgartner ◽  
F. Townsend ◽  
D. A. Pabst ◽  
W. A. Mclellan ◽  
...  
Keyword(s):  
Sertoli Cell ◽  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Cell Tumor ◽  
Adult Males ◽  
Sertoli Cell Tumor ◽  
Stenella Frontalis ◽  
First Report ◽  
Spotted Dolphin

Seminoma with metastasis was diagnosed in a spotted dolphin ( Stenella frontalis) and an Atlantic bottlenose dolphin ( Tursiops truncatus). Sertoli cell tumor and pheochromocytoma were also diagnosed in the spotted dolphin. The spotted and bottlenose dolphins were adult males that stranded and died on the coasts of northwest Florida and southeast North carolina, respectively. Neoplasia is infrequently reported in cetaceans. This is the first report of seminoma, Sertoli cell tumor, and pheochromocytoma in a dolphin, the first report of three distinct neoplasms in a dolphin, and one of the few reports of malignant neoplasia in dolphins.

scholarly journals Directionality of Sexual Activities During Mixed-Species Encounters between Atlantic Spotted Dolphins (Stenella frontalis) and Bottlenose Dolphins (Tursiops truncatus)

2013 ◽  
Vol 26 (2) ◽  
Author(s):  
Denise L. Herzing ◽  
Cindy R. Elliser
Keyword(s):  
Social Interactions ◽  
Adult Male ◽  
Bottlenose Dolphin ◽  
Bottlenose Dolphins ◽  
Aggressive Behaviors ◽  
Mixed Species ◽  
The Bahamas ◽  
Stenella Frontalis ◽  
Spotted Dolphin ◽  
Atlantic Spotted Dolphins

In the Bahamas, interspecific groups of Atlantic spotted dolphins, Stenella frontalis, and bottlenose dolphins, Tursiops truncatus, have been observed underwater since 1985 on Little Bahama Bank. Mixed-species groups engage in associative behaviors and aggression on a regular basis. Because of their complex cognitive behaviors and large brain encephalization, dolphins are likely capable of complex social interactions, even between species.Between 1993-2003, 177 Mixed-Species Encounters (MSE) were categorized by the age class of male spotted dolphins, the ratio of spotted dolphins to bottlenose dolphins, behavior as Associative (traveling, babysitting, play) or Aggressive (chases, mounting, head to heads) and by directionality of sexual behavior. The majority (68%) of MSE involved adult spotted dolphin. Associative behaviors were observed more than aggressive behaviors in groups where no adult male spotted dolphin, only male calves, or male juvenile spotted dolphins were present. Aggressive behaviors were observed more frequently than associative behaviors in adult male spotted dolphin groups. When groups were unbalanced in favor of one species or the other, differences in social interactions occurred. Male spotted dolphins were never observed attempting to mount male bottlenose dolphin although they chased them. Despite the larger ratio of male spotted dolphins to bottlenose dolphins during MSE, directionality of male-to-male sexual contact was primarily one-way. Male bottlenose dolphin mounted and copulated with male spotted dolphins but not the reverse. Opportunities for cross-species mating and hybridization clearly occurred. Male bottlenose dolphins copulated with female spotted dolphins and male spotted dolphins copulated with female bottlenose dolphins. These sympatric dolphins in the Bahamas have a complex and dynamic relationship that varies with sex and age and revolves around potential reproductive isolation issues.

Current status of Odontocetes in the Antarctic

1995 ◽  
Vol 7 (4) ◽  
pp. 365-379 ◽  
Author(s):  
Fujio Kasamatsu ◽  
Gerald G. Joyce
Keyword(s):  
Sperm Whale ◽  
Current Status ◽  
Line Transect ◽  
Sperm Whales ◽  
Killer Whales ◽  
Northern Regions ◽  
Beaked Whales ◽  
Pilot Whales ◽  
Using Data ◽  
The Antarctic

The current status of Antarctic Odontocetes – sperm whales Physeter catodon, killer whales Orcinus orca, long-finned pilot whales Globicephala melaena, hourglass dolphins Lagenorhynchus cruciger and poorly known species of beaked whales (family Ziphiidae)–were studied in Anatarctic waters using data gathered in sighting surveys conducted from 1976/77 to 1987/88. Temporal variation in density demonstrated the different migration patterns by species, especially between sperm whale and killer whale. Spatial distributions during mid-summer demonstrated different peaks of occurrence for each species by latitude that suggest possible segregation between the species. Killer whales occur mainly in the very southernmost areas, sperm whales in the southern half of the study area, beaked whales (mostly southern bottlenose whales Hyperoodon planifrons) ranged over a wide area, and long-finned pilot whales and hourglass dolphins were mainly in the northern regions of Antarctic waters. Several longitudinal peaks of occurrence and apparent distribution gaps were identified for sperm, beaked and killer whales. Abundance estimates for south of the Antarctic Convergence in January are based on line transect theory and were 28 100 animals (coefficient of variation CV 0.18) sperm whales, 599 300 (0.15) beaked whales (mostly southern bottlenose whales), 80 400 (0.15) killer whales, 200 000 (0.35) long-finned pilot whales, and 144 300 (0.17) hourglass dolphins. Based on this, biomass of these species were estimated as 0.77 (sperm whales), 2.70 (beaked whales), 0.32 (killer whales), 0.16 (long-finned pilot whales) and 0.01 (hourglass dolphins) million tonnes. Consumption of food (mostly squid) by the Odontocetes is estimated as 14.4 million tonnes with 67% of the total consumed by beaked whales. Indirect consumption of Antarctic krill through the predation of squid by beaked whales is estimated to be c. 24 million tonnes. This value is similar to the estimate of krill consumption by penguins in the Antarctic (33 million tonnes). Odontocetes, especially southern bottlenose whales, are suggested to have a much greater role in the Antarctic ecosystem than has previously been considered.

scholarly journals Cetaceans observed in Suriname and adjacent waters

2015 ◽  
Vol 10 (1) ◽  
pp. 2-19 ◽  
Author(s):  
Marijke Nita De Boer
Keyword(s):  
Bottlenose Dolphin ◽  
Sperm Whale ◽  
Seismic Survey ◽  
Marine Biodiversity ◽  
Common Dolphin ◽  
Cetacean Species ◽  
Spotted Dolphin ◽  
Common Bottlenose Dolphin ◽  
Delphinus Capensis ◽  
Guiana Dolphin

Very little information exists about the cetaceans in the Guianas: Suriname and its neighboring countries Guyana and French Guiana. During a dedicated cetacean survey carried out from a geophysical seismic survey vessel in the offshore waters of Suriname (May-September 2012), the occurrence of 13 cetacean species was documented and of those, 11 were newly documented for this area. The species observed by the author included sperm whale (Physeter macrocephalus), Bryde’s whale (Balaenoptera edeni), false killer whale (Pseudorca crassidens), melon-headed whale (Peponocephala electra), roughtoothed dolphin (Steno bredanensis), long-beaked common dolphin (Delphinus capensis), Fraser’s dolphin (Lagenodelphis hosei), pantropical spotted dolphin (Stenella attenuata) and spinner dolphin (Stenella longirostris). During transit to the survey area (Trinidad to Suriname) incidental sightings were recorded which included common bottlenose dolphin (Tursiops truncatus) off Trinidad, Stenella sp. off Guyana and Guiana dolphin (Sotalia guianensis) at the entrance of the Suriname River. Opportunistic records originating from the periods December 2008-March 2009 and August-October 2012 were forwarded to the author. These records included common bottlenose dolphin, Atlantic spotted dolphin (Stenella frontalis) and short-finned pilot whale (Globicephala macrorhynchus). There is a growing need to identify critical areas for marine biodiversity conservation, both locally and regionally. This paper describes the general occurrence of the cetacean community encountered in Suriname waters in summer. The study revealed that the offshore cetacean community in Suriname is best described as primarily a tropical community, dominated by odontocetes (dolphins and sperm whales). Although the species diversity was relatively high, the overall cetacean relative abundance index (number of animals per 100km effort) was low, which is consistent for tropical equatorial offshore waters. Apart from the sperm whale and the Guiana dolphin, all the other species recorded represent new species records for Suriname. It is recommended that more continuous monitoring in different seasons be carried out in order to gain a better understanding of the occurrence, distribution and status of the different cetacean species within the region. 

First record of the superfamily Proctotrupoidea from French Polynesia (Hymenoptera)

2020 ◽  
Vol 125 (4) ◽  
pp. 404-406
Author(s):  
Thibault Ramage
Keyword(s):  
First Record ◽  
French Polynesia ◽  
Society Islands ◽  
First Time

A Helorid wasp, Helorus ruficornis Förster, 1856, is reported for the first time on Tahiti (Society Islands), which is also the first record of both Proctotrupoidea and family Heloridae in French Polynesia. The potential hosts of Helorus ruficornis in French Polynesia are discussed.

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