Age and growth of franciscana dolphins, <i>Pontoporia blainvillei</i> (Cetacea: Pontoporiidae) incidentally caught off southern Brazil and northern Argentina

Botta, Silvina; Secchi, Eduardo R.; Muelbert, Mônica M. C.; Danilewicz, Daniel; Negri, María Fernanda; Cappozzo, Humberto Luis; Hohn, Aleta A.

doi:10.1017/s0025315410001141

Cited by 27 publications

(37 citation statements)

References 29 publications

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“…P. blainvillei is the only extant species of the family Pontoporiidae (May-Collado and Agnarsson, 2006;McGowen et al, 2009), and is one of the smallest cetaceans, maximum body length reported is 171 and 152 cm for females and males, respectively (Kasuya and Brownell, 1979;Botta et al, 2010). P. blainvillei, together with Inia geoffrensis, form the sister group to the Delphinoidea, which includes monodontids, porpoises, and ocean dolphins (Yan et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Ontogenetic development and sexual dimorphism of franciscana dolphin skull: A 3D geometric morphometric approach

Castillo

Flores

Cappozzo

2014

Journal of Morphology

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The aim of this work was to study the postnatal ontogenetic development of Pontoporia blainvillei skull, identifying major changes on shape, and relating them to relevant factors in the life history of the species. We analyzed a complete ontogenetic series (73♂, 83♀) with three-dimensional geometric morphometric techniques. Immature dolphins showed a very well-developed braincase and a poorly developed rostrum, and the principal postnatal changes affected the rostrum and the temporal fossa, both structures implied functionally to the feeding apparatus, thus suggesting a specialized mode for catch fast prey in P. blainvillei. Osseous elements associated with sound production were already well developed on immature dolphins, suggesting the importance of this apparatus since the beginning of postnatal life. Sexual dimorphism was detected on both shape and size variables. Females were bigger than males, in accordance with previous studies. Shape differences between sexes were found on the posterior part of premaxillaries and external bony nares (P < 0.01), suggesting that this sexual dimorphism is related to differences on vocalization capabilities.

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Section: Introductionmentioning

confidence: 99%

Ontogenetic development and sexual dimorphism of franciscana dolphin skull: A 3D geometric morphometric approach

Castillo

Flores

Cappozzo

2014

Journal of Morphology

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“…Because the bay is formed by an estuary characterized by calm and shallow waters, an absence of large predators and is resource rich, it represents a high quality natural habitat were dolphins feed, rest, and reproduce, and where both dolphin populations show a high degree of residency (Cremer and Simões‐Lopes , Botta et al . , Hardt et al . ).…”

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confidence: 99%

Breathing synchrony in franciscana (Pontoporia blainvillei) and Guiana dolphins (Sotalia guianensis) in Southern Brazil

Actis

Danilewicz

Cremer

et al. 2018

Marine Mammal Science

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Synchronous breathing may be a useful proxy for studying other, and perhaps more complex, aspects of cetacean behavior. Here we describe a study conducted in Babitonga Bay, southern Brazil, where we investigated the synchrony of breathing in two small populations of franciscana (Pontoporia blainvillei) and Guiana dolphins (Sotalia guianensis). The bay is affected by different sources of anthropogenic disturbances, such as boat activity and point-source pollution. We assumed breathing synchrony to be the inverse of the time between breathing surfacing displays of dolphins within a swimming pair, which we refer to as lag. The relationship between lag and anthropogenic and animal-related variables was evaluated with generalized additive models. For franciscana dolphins, breathing synchrony was only positively related to the proximity between animals. Breathing synchrony in Guiana dolphins was positively related to both the proximity between animals and to group size, and varied significantly depending on the research boat used. Proximal characteristics (i.e., of individuals or of the group) of these dolphin species seem to be more related to the synchronization in breathing than are the environmental variables assessed here. Results presented expand the current knowledge of these two dolphin species and provide general insights into the breathing synchrony for cetaceans.

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“…), although further unpublished studies exist. This species is one of the smallest odontocetes; estimates of asymptotic length range from 129 to 158 cm for females and 113 to 136 cm for males, with long recognition that females are larger than males (Barreto & Rosas, 2006;Botta et al, 2010). Age at sexual maturation (ASM) reported in the above-mentioned studies range from 2.7 to 5 years for females at average lengths of 122-140 cm.…”

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confidence: 99%

Reproductive parameters of franciscana dolphins (Pontoporia blainvillei) of Southeastern Brazil

Silva

Barbosa

Conversani

et al. 2020

Marine Mammal Science

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Reproductive parameters of 168 franciscana dolphins, Pontoporia blainvillei (73 females and 95 males) incidentally caught (n = 163) or stranded (n = 5) between 2005 and 2016 in southeastern Brazil are presented. Ovarian macroscopic analysis revealed 55 immature (75.3%) and 18 mature (24.7%) females. Annual pregnancy rate was estimated to be 0.36, with a calving interval of 2.8 years. Testicular histology revealed 66 immature (69.5%) and 29 mature (30.5%) males. Males with combined testis weight above 4 g were mature, and 1-year-old mature males and a 2-year-old pregnant female are reported for the first time for the species. Reproductive seasonality does not seem to occur in the study area. Mean age and length at sexual maturation were estimated to be at 2.7 years and 128.5 cm for females, and 2.7 years and 114.0 cm for males. These estimates are lower than most of the estimates for this species. These results add novel and valuable information on the reproductive patterns of this endangered species, threatened by high levels of mortality in gill net fisheries. The information presented here represents an important effort to obtain more reliable parameter estimates for the studied area, needed for a better assessment of its current conservation status.

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Age and growth of franciscana dolphins, Pontoporia blainvillei (Cetacea: Pontoporiidae) incidentally caught off southern Brazil and northern Argentina

Cited by 27 publications

References 29 publications

Ontogenetic development and sexual dimorphism of franciscana dolphin skull: A 3D geometric morphometric approach

Ontogenetic development and sexual dimorphism of franciscana dolphin skull: A 3D geometric morphometric approach

Breathing synchrony in franciscana (Pontoporia blainvillei) and Guiana dolphins (Sotalia guianensis) in Southern Brazil

Reproductive parameters of franciscana dolphins (Pontoporia blainvillei) of Southeastern Brazil

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