This thesis examines the characteristics of dusky dolphin (Lagenorhynchus obscurus) nursery groups and ontogeny of dusky dolphin calves. Data were collected via boat-based group focal follows of nurseries from October 2006-May 2007. A total of 87 nursery groups were encountered. Data were analyzed according to age category (infant or yearling) and season (early or late). Nursery group membership was lowest in the early season and when yearlings were present. The average number of yearlings in a nursery group was less than that of infants. The predominant activity of calves was rest. Early infants rested the most, while travel seemed most important for late infants, and early yearlings were most likely to forage. With the exception of early infants, all calves were more likely than adults to interact with boats. When taking month into account, yearlings were more social in general than infants. Infants showed a positive trend in sociality, while yearling sociality remained relatively stable. Nursery groups are markedly segregated by calf age, and 80% of nursery groups contained calves of only one age group. Dusky dolphin calves show a similar trend in preference for position in relation to the mother as that in bottlenose dolphins (Tursiops sp.), with echelon swim decreasing with age. However, all calves appear to prefer echelon swim when nursery groups are traveling. Calves were more likely to swim independently in the late part of the season and while foraging or socializing, and were more likely to be in close proximity to their mothers while resting or traveling. Calves learned noisy leaps, followed by clean, coordinated, and acrobatic leaps, in that order. There was no clear relationship between behavioral state and types of leaps performed by calves. Early infants leapt less often than older calves, but leap frequency did not differ among the older calves. The overall pattern in the ontogeny of dusky dolphin leaps indicates that the physical development of leaps is learned individually, while the context in which the leaps are performed is learned from conspecifics. These results indicate that nursery groups represent an important environment for healthy physical and social development of calves.

This thesis examines the characteristics of dusky dolphin (Lagenorhynchus obscurus) nursery groups and ontogeny of dusky dolphin calves. Data were collected via boat-based group focal follows of nurseries from October 2006-May 2007. A total of 87 nursery groups were encountered. Data were analyzed according to age category (infant or yearling) and season (early or late). Nursery group membership was lowest in the early season and when yearlings were present. The average number of yearlings in a nursery group was less than that of infants. The predominant activity of calves was rest. Early infants rested the most, while travel seemed most important for late infants, and early yearlings were most likely to forage. With the exception of early infants, all calves were more likely than adults to interact with boats. When taking month into account, yearlings were more social in general than infants. Infants showed a positive trend in sociality, while yearling sociality remained relatively stable. Nursery groups are markedly segregated by calf age, and 80% of nursery groups contained calves of only one age group. Dusky dolphin calves show a similar trend in preference for position in relation to the mother as that in bottlenose dolphins (Tursiops sp.), with echelon swim decreasing with age. However, all calves appear to prefer echelon swim when nursery groups are traveling. Calves were more likely to swim independently in the late part of the season and while foraging or socializing, and were more likely to be in close proximity to their mothers while resting or traveling. Calves learned noisy leaps, followed by clean, coordinated, and acrobatic leaps, in that order. There was no clear relationship between behavioral state and types of leaps performed by calves. Early infants leapt less often than older calves, but leap frequency did not differ among the older calves. The overall pattern in the ontogeny of dusky dolphin leaps indicates that the physical development of leaps is learned individually, while the context in which the leaps are performed is learned from conspecifics. These results indicate that nursery groups represent an important environment for healthy physical and social development of calves.

I characterized dusky dolphin (Lagenorhynchus obscurus) underwater bait-balling behaviors and acoustic signals, and compared data between Argentina and New Zealand (NZ) to investigate the roles of ecology versus social learning. I quantified prey herding and capturing behaviors from video footage, and I analyzed acoustic signals from narrowband recordings. In both locations, I related bait-balling behaviors and acoustic signals to group and prey ball sizes. In NZ, I also related dolphin behaviors to prey ball escape behaviors and acoustic signal parameters to examine proximate functions. Observed herding behaviors typically involved dolphins swimming around or under a prey ball using a side body orientation, while dolphins typically captured fish from the side of a prey ball using a ventral orientation. Coordinated prey-capture behaviors may have made it easier for dolphins to capture fish by trapping fish between dolphins. Signals were categorized as click trains, burst pulses, and combinations due to a bimodal inter-click interval distribution. I observed 3 whistle-like chirp-screams, but no whistles. Sequences of burst pulses also occurred that contained 2-14 burst pulses that aurally and visually appeared closely matched. Similarities between locations suggest that ecological context related to broad behavioral and acoustic parameters, while social learning differences may occur on a finer scale. In NZ, prey balls exhibited horizontal and vertical movements, but the only behavior that preceded escape was “funneling”, the brief formation of a ball shape where the height was at least twice the width. Dolphin behaviors that related to prey balls ascending were type of herding pass, location of prey-capture attempts, and body orientation during attempts. These behavioral parameters may also be used to counter vertical prey escape behaviors. In NZ, all signal categories had a direct or indirect role in capturing prey. Click train-burst pulses were likely used for echolocating on prey, burst pulses and sequences appeared to have communication roles, and the role of click trains was ambiguous. No signal categories appeared to have a herding function, but the sheer number of signals emitted may have caused fish to cluster together more tightly and therefore facilitated capture.

O presente estudo teve como objetivo investigar a influência da incorporação da dieta com óleo de peixe (OP), rico em 22:6n3 (DHA) e 20:5n3 (EPA); óleo de linhaça (OL), rico em 18:3n3 (LNA); e óleo de coco (OC), rico em ácidos graxos saturados, no metabolismo lipídico de fêmeas adultas de Epinhephelus marginatus (garoupa verdadeira). Adicionalmente foi realizado o sequenciamento e montagem de novo do transcriptoma do tecido hepático de E. marginatus por Next Generation Sequence, e as sequências obtidas foram utilizadas como ferramenta para validar genes relacionados com o metabolismo lipídico. Os resultados mostraram que, após 5 meses de experimento, a concentração de lipídios no tecido muscular foi superior nos animais do grupo controle (alimentado apenas com sardinha) devido possivelmente a uma menor digestibilidade dos ácidos graxos incorporados na dieta dos demais grupos experimentais. Em geral os triglicerídios (TG) refletiram mais a dieta do que os fosfolipídios (PL), e foram marcados pelo alto percentual de 18:3n3 nos animais do grupo OL em todos os tecidos, e DHA na musculatura dos animais do grupo OP. Aparentemente os resultados observados para os ácidos graxos saturados e monoinstaruados sugerem um potencial autorregulatório para processos de retenção e oxidação de ácidos graxos para esta espécie, já que em geral os tecidos não refletiram diretamente a composição da dieta. A suplementação da dieta com diferentes óleos interferiu de forma direta na expressão dos genes relacionados com a síntese e β-oxidação de ácidos graxos. A expressão do gene ELOVL5 presumivelmente influenciou na deposição de ácidos graxos intermediários nos tecidos dos animais de todos os grupos experimentais, que não foram observados, ou foram pouco representativos nas dietas experimentais. O sequenciamento dos transcritos do tecido hepático de E. marginatus gerou 92.887 contigs de alta qualidade, e foi observado maior número de anotações funcionais contra o banco de proteínas de zebrafish (Danio rerio), comparado ao banco de proteínas de fugu (Takifugu rubripes) . Foram selecionadas as sequências dos genes de interesse no banco de dados local de E. marginatus, e todas as sequências utilizadas apresentaram alto grau de similaridade e foram consideradas adequadas para a realização das análises de PCR em tempo real / This study aimed to investigate the influence of dietary supplementation with fish oil (OP), rich in 22:6n3 (DHA) and 20:5n3 (EPA); linseed oil (OL), rich in 18:3n3 (LNA); and coconut oil (OC), rich in saturated fatty acids in the lipid metabolism of Epinephelus marginatus (dusky grouper) adult female. Additionally it was performed sequencing and de novo assembly of the E. marginatus liver transcriptome by Next Generation Sequence, and sequences obtained were used as a tool to validate lipid-relevant genes. The results showed that the lipid concentration in the liver was higher in the control group (fed only with sardine) possibly due to a reduced digestibility of the incorporated fatty acids in the diet from the other experimental groups. In general the triglycerides (TG) of tissues reflected more the diet profile than phospholipids (PL), and were characterized by the high percentages of 18:3n3 in the OL group in all tissues, and DHA in the muscles of the OP group. Apparently the results for the saturated and monounsaturated fatty acids suggest a self-regulatory potential for retention and oxidation processes for this species, since in general the tissues did not directly reflect the fatty acid diet composition. The ELOVL5 expression presumably influenced in the fatty acids intermediate deposition in the animal tissue from all experimental groups, which were not seen or not representative in the experimental diets. The sequencing of the transcripts from E. marginatus liver generated 92,887 high quality contigs, and it was observed a higher number of functional annotations against zebrafish (Danio rerio) proteins database, compared to the fugu Takifugu rubripes) proteins database. It was selected sequences of interest genes in the local database of E. marginatus, and all sequences used showed a high similarity degree with another teleosteo species, and were considered adequate to run the real time PCR analyze