Alimentación del delfín costero, Sotalia guianensis (Cetacea: Delphinidae), en la bahía Norte al sur de Brasil

The stomach contents of 18 Guiana dolphins stranded or accidentally caught by fishing around Norte Bay of Santa Catarina Island between 1990 and 2006 were examined. The small population of Guiana dolphins studied showed a varied diet, and prey was caught disproportionately. The stomach contents of these dolphins consisted of 448 prey remains coming from 18 species and 10 families. Their diet primarily consisted of fish, but also shrimp and squid. The most important species were cutlass fish (Trichiurus lepturus) and white mouth croaker (Micropogonias furnieri), which together comprised 75% of the total biomass. Although prey size ranged widely from 1.4 to 92.8 cm, a prevalence of prey smaller than 20 cm was observed. There was a predominance of prey living in moderate or large schools. The prey also had a wide vertical distribution in the water column. Our results support the opportunistic feeding habit of the Guiana dolphin, since its diverse diet was clearly guided by the availability and accessibility of resources in its habitat.Se estudiaron los contenidos del estómago de 18 delfines costeros capturados accidentalmente por redes de pesca o encontrados encallados alrededor de la bahía Norte de la isla de Santa Catarina entre 1990 y 2006. La composición de la dieta de los delfines fue variada, pero con predominio de algunas presas. Los contenidos estomacales consistieron en 448 restos de presas, que correspondieron a 18 especies y 10 familias. La mayoría de las presas fueron principalmente peces, pero también estuvieron representados cefalópodos y crustáceos. Las especies más importantes fueron el pez sable (Trichiurus lepturus) y la corvina rubia (Micropogonias furnieri), que juntos representaron un 75% de la biomasa total. Aunque el tamaño medio de las presas varió entre 1.4 y 92.8 cm, hubo una prevalencia de presas más pequeñas de 20 cm. Se observó un predominio de presas que viven agregadas en cardúmenes de mediano a gran tamaño y con amplia distribución vertical en la columna de agua. Nuestros resultados apoyan el hábito alimenticio oportunista de Sotalia guianensis, ya que su variada dieta está claramente guiada por la disponibilidad y accesibilidad de los recursos en su hábitat

Dolphin population specialized in foraging with artisanal fishers requires zero-bycatch management to persist

This study was conducted as part of a PhD thesis in the Graduate Programme in Ecology at the Federal University of Santa Catarina, with funding provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – 407190/2012-0) and Fundação de Amparo à Pesquisa e Inovação do Estado de Santa Catarina (FAPESC – TR2012000295). This study is also part of the SELA Long-Term Ecological Research Programme (PELD CNPq – 445301/2020-1). C.B. received a doctoral scholarship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); P.C.S.L. received a research grant from CNPq (305573/2013-6); F.G.D.J. received a research grant from CNPq (308867/2019-0).1. The small population paradigm assumes that populations with low numbers of individuals intrinsically have a high probability of extinction. The small population of Lahille's bottlenose dolphins Tursiops truncatus gephyreus that specializes in foraging with artisanal fishers in Laguna, southern Brazil, faces human pressures including bycatch in fishing gear. The viability of this population was modelled over 30 and 100 years under different levels of bycatch, including the current scenario of two bycatches every year, two scenarios with higher incidence of bycatches and three management scenarios. The sensitivity of predicted growth rates to fixed-proportion and observed-variation changes in life history parameters was explored. 2. The current scenario predicted a declining population (r = -0.014; λ = 0.986) with a high probability of extinction in the long term (PE = 0.71). A small increase in bycatches would result in a marked increase in the probability of extinction. Management scenarios seem promising, but only the zero-bycatch management scenario would make the difference between a declining and an increasing population. 3. As expected for slow-growing species, population growth rate was most sensitive to proportional changes in adult female and juvenile survival. However, considering observed variation in vital rates, population dynamics were most influenced by variation in reproductive rates. 4. To determine the highest priority for management action, another simulation was made of how additional threat scenarios of recognized human activities (i.e. bycatch influencing adult survival and increased underwater noise or pollution influencing calf survival) would affect population dynamics. Population growth rate was very sensitive to changes in adult bycatch (especially females), as expected, and only subtly sensitive to a reduction in calf survival. 5. The current level of bycatch is unsustainable. Bycatch needs to be eliminated to maximize the probability of long-term persistence of this dolphin population. However, this population's persistence could be threatened by natural variation in reproductive rates.PostprintPeer reviewe

Bottlenose dolphin ecotypes of the western South Atlantic: the puzzle of habitats, coloration patterns and dorsal fin shapes

Phenotypic variations occur in several cetacean species, including common bottlenose dolphins Tursiops truncatus, which can also be distinguished as coastal and offshore ecotypes. In the western South Atlantic, these ecotypes have been described based on skeletal morphology and genetics. However, there is still no clear description to recognize them in the field. Here we searched for external diagnostic patterns that may facilitate their visual distinction and investigated their habitat use. We examined dorsal fin shapes and coloration of photo-identified dolphins distributed in a wide geographic range off the coast of southern and southeastern Brazil. A strong differentiation in the dorsal fin shape was observed, with a more falcate shape for offshore dolphins. We also found that offshore individuals have a darker color pattern, while coastal dolphins show 2 wider striped bands at the throat region and a longer rostrum, revealing that the ecotypes can be well distinguished in the field. We also detected differential habitat use. The coastal ecotype inhabits shallow waters (up to 18 m deep) close to the shore (up to 3 km). The offshore ecotype has a wider distribution and more flexible habitat use. It was usually found in coastal and deeper waters (maximum depth of 758 m and >200 km from the coast). Although we observed a small area of overlap in the distribution of the 2 ecotypes, both forms were not seen together. Therefore, our results reinforce the presence of a parapatric distribution and distinct morphology between the ecotypes, supporting their prior description as different subspecies

Nestedness across biological scales

Biological networks pervade nature. They describe systems throughout all levels of biological organization, from molecules regulating metabolism to species interactions that shape ecosystem dynamics. The network thinking revealed recurrent organizational patterns in complex biological systems, such as the formation of semi-independent groups of connected elements (modularity) and non-random distributions of interactions among elements. Other structural patterns, such as nestedness, have been primarily assessed in ecological networks formed by two non-overlapping sets of elements; information on its occurrence on other levels of organization is lacking. Nestedness occurs when interactions of less connected elements form proper subsets of the interactions of more connected elements. Only recently these properties began to be appreciated in one-mode networks (where all elements can interact) which describe a much wider variety of biological phenomena. Here, we compute nestedness in a diverse collection of one-mode networked systems from six different levels of biological organization depicting gene and protein interactions, complex phenotypes, animal societies, metapopulations, food webs and vertebrate metacommunities. Our findings suggest that nestedness emerge independently of interaction type or biological scale and reveal that disparate systems can share nested organization features characterized by inclusive subsets of interacting elements with decreasing connectedness. We primarily explore the implications of a nested structure for each of these studied systems, then theorize on how nested networks are assembled. We hypothesize that nestedness emerges across scales due to processes that, although system-dependent, may share a general.Facultad de Ciencias Naturales y Muse

Nestedness across biological scales

Biological networks pervade nature. They describe systems throughout all levels of biological organization, from molecules regulating metabolism to species interactions that shape ecosystem dynamics. The network thinking revealed recurrent organizational patterns in complex biological systems, such as the formation of semi-independent groups of connected elements (modularity) and non-random distributions of interactions among elements. Other structural patterns, such as nestedness, have been primarily assessed in ecological networks formed by two non-overlapping sets of elements; information on its occurrence on other levels of organization is lacking. Nestedness occurs when interactions of less connected elements form proper subsets of the interactions of more connected elements. Only recently these properties began to be appreciated in one-mode networks (where all elements can interact) which describe a much wider variety of biological phenomena. Here, we compute nestedness in a diverse collection of one-mode networked systems from six different levels of biological organization depicting gene and protein interactions, complex phenotypes, animal societies, metapopulations, food webs and vertebrate metacommunities. Our findings suggest that nestedness emerge independently of interaction type or biological scale and reveal that disparate systems can share nested organization features characterized by inclusive subsets of interacting elements with decreasing connectedness. We primarily explore the implications of a nested structure for each of these studied systems, then theorize on how nested networks are assembled. We hypothesize that nestedness emerges across scales due to processes that, although system-dependent, may share a general.Facultad de Ciencias Naturales y Muse

Nestedness across biological scales

Biological networks pervade nature. They describe systems throughout all levels of biological organization, from molecules regulating metabolism to species interactions that shape ecosystem dynamics. The network thinking revealed recurrent organizational patterns in complex biological systems, such as the formation of semi-independent groups of connected elements (modularity) and non-random distributions of interactions among elements. Other structural patterns, such as nestedness, have been primarily assessed in ecological networks formed by two non-overlapping sets of elements; information on its occurrence on other levels of organization is lacking. Nestedness occurs when interactions of less connected elements form proper subsets of the interactions of more connected elements. Only recently these properties began to be appreciated in one-mode networks (where all elements can interact) which describe a much wider variety of biological phenomena. Here, we compute nestedness in a diverse collection of one-mode networked systems from six different levels of biological organization depicting gene and protein interactions, complex phenotypes, animal societies, metapopulations, food webs and vertebrate metacommunities. Our findings suggest that nestedness emerge independently of interaction type or biological scale and reveal that disparate systems can share nested organization features characterized by inclusive subsets of interacting elements with decreasing connectedness. We primarily explore the implications of a nested structure for each of these studied systems, then theorize on how nested networks are assembled. We hypothesize that nestedness emerges across scales due to processes that, although system-dependent, may share a general.Facultad de Ciencias Naturales y Muse

Safeguarding human–wildlife cooperation

Human–wildlife cooperation occurs when humans and free-living wild animals actively coordinate their behavior to achieve a mutually beneficial outcome. These interactions provide important benefits to both the human and wildlife communities involved, have wider impacts on the local ecosystem, and represent a unique intersection of human and animal cultures. The remaining active forms are human–honeyguide and human–dolphin cooperation, but these are at risk of joining several inactive forms (including human–wolf and human–orca cooperation). Human–wildlife cooperation faces a unique set of conservation challenges, as it requires multiple components—a motivated human and wildlife partner, a suitable environment, and compatible interspecies knowledge—which face threats from ecological and cultural changes. To safeguard human–wildlife cooperation, we recommend: (i) establishing ethically sound conservation strategies together with the participating human communities; (ii) conserving opportunities for human and wildlife participation; (iii) protecting suitable environments; (iv) facilitating cultural transmission of traditional knowledge; (v) accessibly archiving Indigenous and scientific knowledge; and (vi) conducting long-term empirical studies to better understand these interactions and identify threats. Tailored safeguarding plans are therefore necessary to protect these diverse and irreplaceable interactions. Broadly, our review highlights that efforts to conserve biological and cultural diversity should carefully consider interactions between human and animal cultures. Please see AfricanHoneyguides.com/abstract-translations for Kiswahili and Portuguese translations of the abstract