Demography of the bottlenose dolphin<i>Tursiops truncatus</i>(Mammalia: Delphinidae) in the Eastern Ligurian Sea (NW Mediterranean): quantification of female reproductive parameters

Rossi, Alessia; Scordamaglia, E.; Bellingeri, M.; Gnone, G.; Nuti, S.; Salvioli, F.; Manfredi, Piero; Santangelo, Giovanni

doi:10.1080/24750263.2017.1334839

Cited by 11 publications

(13 citation statements)

References 24 publications

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“…We assumed that a calf stayed with its mother until its third year (Mann et al, 2000), and that a given female could not have several young at the same time. This is corroborated by studies on calving intervals, which are estimated to be around 3-4 years in the bottlenose dolphin (Fruet, Genoves, Möller, Botta, & Secchi, 2015;Mann et al, 2000;Rossi et al, 2017;Steiner & Bossley, 2008). We defined four events that were coded in the capture histories:…”

Section: Multievent Capture-recapture Modelsmentioning

confidence: 88%

“…The notable difference in observation probability in these two age classes is a little perplexing, as the detection probability for a female with a YOY was higher than for a female with a calf. It is possible that this could be explained by the fact that “sighted” in this study meant in reality “identified in pictures.” While observers made a greater effort to take pictures of females with a YOY (as reflected by the higher detection probability for these females), because of their small size (Rossi et al, ) and their proximity to their mother, which can mask them, YOY may remain unobserved in the pictures.…”

Section: Discussionmentioning

confidence: 99%

“…It is possible that this could be explained by the fact that "sighted" in this study meant in reality "identified in pictures." While observers made a greater effort to take pictures of females with a YOY (as reflected by the higher detection probability for these females), because of their small size (Rossi et al, 2017) and their proximity to their mother, which can mask them, YOY may remain unobserved in the pictures.…”

Section: Re Sultsmentioning

confidence: 99%

“…In this study, we were particularly interested in estimating the reproductive parameters of a population of bottlenose dolphins (Tursiops truncatus) with a new approach which could be used for other cetacean species. In wild cetacean populations, methods aiming at providing estimates of the reproductive rate, reproductive success, calf survival, and proportion of breeding female usually relied on raw count of breeding and nonbreeding adults, newborns, and juveniles, for purely descriptive statistics (see, for instance, Herzing, 1997;Rossi et al, 2017). Other studies used inferential statistical methods, like linear regression (Baker, O'Brien, McHugh, & Berrow, 2018) or general linear mixed models (Brough, Henderson, Guerra, & Dawson, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Joint estimation of survival and breeding probability in female dolphins and calves with uncertainty in state assignment

Couet

Gally

Canonne

et al. 2019

Ecology and Evolution

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While the population growth rate in long‐lived species is highly sensitive to adult survival, reproduction can also significantly drive population dynamics. Reproductive parameters can be challenging to estimate as breeders and nonbreeders may vary in resighting probability and reproductive status may be difficult to assess. We extended capture–recapture (CR) models previously fitted for data on other long‐lived marine mammals to estimate demographic parameters while accounting for detection heterogeneity between individuals and state uncertainty regarding reproductive status. We applied this model to data on 106 adult female bottlenose dolphins observed over 13 years. The detection probability differed depending on breeding status. Concerning state uncertainty, offspring were not always sighted with their mother, and older calves were easier to detect than young‐of‐the‐year (YOY), respectively, 0.79 (95% CI 0.59–0.90) and 0.58 (95% CI 0.46–0.68). This possibly led to inaccurate reproductive status assignment of females. Adult female survival probability was high (0.97 CI 95% 0.96–0.98) and did not differ according to breeding status. Young‐of‐the‐year and 1‐year‐old calves had a significantly higher survival rate than 2‐year‐old (respectively, 0.66 CI 95% 0.50–0.78 and 0.45 CI 95% 0.29–0.61). This reduced survival is probably related to weaning, a period during which young are exposed to more risks since they lose protection and feeding from the mother. The probability of having a new YOY was high for breeding females that had raised a calf to the age of 3 or lost a 2‐year‐old calf (0.71, CI 95% 0.45–0.88). Yet, this probability was much lower for nonbreeding females and breeding females that had lost a YOY or a 1‐year‐old calf (0.33, 95% CI 0.26–0.42). The multievent CR framework we used is highly flexible and could be easily modified for other study questions or taxa (marine or terrestrial) aimed at modeling reproductive parameters.

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Section: Multievent Capture-recapture Modelsmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Re Sultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Joint estimation of survival and breeding probability in female dolphins and calves with uncertainty in state assignment

Couet

Gally

Canonne

et al. 2019

Ecology and Evolution

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“…The reproductive output of wild bottlenose dolphins Tursiops truncatus has been extensively explored worldwide (Fruet et al 2015, Rossi et al 2017, Baker et al 2018, especially for resident populations inhabiting estuary areas of sub-tropical regions (Shane et al 1986, Steiner & Bossley 2008, Bezamat et al 2020; however, it remains largely undocumented in the Mediterranean Sea, where bottlenose dolphins have been studied only in relatively small areas (Gol'din & Gladilina 2015, Rossi et al 2017. Bottlenose dolphins live in fission− fusion societies characterized by ex tensive maternal investment, with prolonged mother− infant relationships and juveniles occasionally associating with their mothers post-weaning (Oftedal 1997, Mann & Smuts 1998.…”

Section: Introductionmentioning

confidence: 99%

Female reproductive output in a Mediterranean bottlenose dolphin Tursiops truncatus population

Blasi¹,

Bruno²,

Boitani

2020

Aquat. Biol.

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The reproductive output of wild bottlenose dolphins Tursiops truncatus has extensively been investigated; nevertheless, it remains widely unexplored in the Mediterranean Sea. We investigated the reproductive history of female bottlenose dolphins in the Aeolian Archipelago (Italy). Thirteen years of photo-identification data were used to track the reproductive pattern of 7 females and their 16 calves. The birth period was accurately estimated within 1 mo for 6 calves (37.5%), peaking in June/July. The mean number of calves for females was 2.3 ± 1.1 (SD), ranging from 1 to 4. The mean interbirth interval was 3.5 ± 1.6 yr, ranging from 2 to 7 yr. The mean weaning age was 3.2 ± 0.6 yr, although 1 calf may have been weaned as late as its fifth birthday. Mother-calf postweaning associations were tracked for 9 calves and ranged from 4 to 10 yr of residence in the maternal group of the calf. The age of first pregnancy was 7.5 yr. The number of calves was influenced by the mean maternal group size, with females that were sighted in larger groups having more calves. However, the number of calves was not influenced by the strength of the associations of mothers with other females. Calf mortality by age 1 was high (12.5%). Two juveniles also died postweaning within 6 yr of their birth. Finally, 2 females may have died during the study, as they were not re-sighted at the end of the study. Our results highlight the need to implement urgent conservation actions to protect this bottlenose dolphin population.

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37 Demography and Conservation of Deep Corals: The Study of Population Structure and Dynamics

Bramanti¹,

Santangelo²,

Benedetti³

et al. 2019

Mediterranean Cold-Water Corals: Past, Present and Future

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Demography of the bottlenose dolphinTursiops truncatus(Mammalia: Delphinidae) in the Eastern Ligurian Sea (NW Mediterranean): quantification of female reproductive parameters

Cited by 11 publications

References 24 publications

Joint estimation of survival and breeding probability in female dolphins and calves with uncertainty in state assignment

Joint estimation of survival and breeding probability in female dolphins and calves with uncertainty in state assignment

Female reproductive output in a Mediterranean bottlenose dolphin Tursiops truncatus population

37 Demography and Conservation of Deep Corals: The Study of Population Structure and Dynamics

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