Orientador: Edmir Daniel Carvalho / Banca: João Henrique Pinheiro Dias / Banca: Marcos Gomes Nogueira / Resumo: Não disponível / Abstract: Not available / Mestre

Orientador: Francisco Langeani / Banca: Cláudio Henrique Zawadzki / Banca: Edson Henrique Lopes Pereira / Resumo: Neoplecostomus Eigenman & Eigenmann, (1888), Neoplecostominae, abriga espécies de cascudo de pequeno porte, com treze espécies válidas muito semelhantes morfologicamente e com populações restritas às cabeceiras de riachos. Dados moleculares recentes apontaram que apesar das aparentes semelhanças morfológicas, algumas populações do alto rio Paraná divergem geneticamente. Devido a esta e outras evidências, como dimorfismo sexual, padrões de placas divergentes e dados morfométricos e merísticos, espécies novas foram descritas para a bacia do alto rio Paraná. Neste trabalho, Neoplecostomus sp. n., da bacia do alto rio Tietê, drenagem do alto rio Paraná é descrita. A espécie nova difere de todas as outras espécies por apresentar dimorfismo sexual, com fêmeas apresentando maior largura mandibular, 16,2-18,2% no comprimento da cabeça (vs. 11,6-14,3% em machos) e maior número de dentes que machos, tanto no dentário 30-38 (vs. 12-18 em machos) (caráter compartilhado com Neoplecostomus langeanii), quanto no pré-maxilar 31-38 (vs. 14-21). Este caráter é o primeiro registro para um neoplecostomíneo. Difere também de todas as outras espécies pela presença de quatro a cinco placas entre o pré-frontal e frontal (vs. 1-3 nas outras espécies), e de todas as espécies do alto rio Paraná pela presença da placa lateronasal, que quando desenvolvida forma a borda lateral da narina. Adicionalmente uma descrição osteológica completa da espécie-tipo Neoplecostomus microps (Steindachner, 1876) é apresentada. Trazemos algumas considerações sobre Neoplecostomus ribeirensis (bacia do rio Ribeira de Iguape), uma vez que o posicionamento da espécie na filogenia de Neoplecostominae, nos trabalhos que abordam dados moleculares, mostra Neoplecostomus ribeirensis mais relacionado à Isbrueckerichthys que as demais espécies cogenéricas / Abstract: Neoplecostomus Eigenman & Eigenmann, 1888 Neoplecostominae, shelter species of catfishes small, with thirteen valid species morphologically very similar and populations restricted to headwaters streams. Recent molecular data pointed out that despite the apparent morphological similarities, some populations in the upper rio Paraná basin genetically differ significantly. So, here we propose a new species Neoplecostomus sp. n. from the upper rio Tietê, upper rio Paraná drainage. The new species is distinguished from congeners by presenting sexual dimorphism, with females having greater width of mandible 16.2-18.2% in the length of the head (vs. 11.6-14.3% in males) and a greater number of teeth than males in both the dental 30-38 (vs. 12-18), as in the pre-maxillary 31-38 (vs. 14-21) (this is the first record of this dimorphism to a Neoplecostominae); present 4 to 5 plates between the frontal and prefrontal (vs. 1-3). Differs from all species of the rio Paraná by having the plate lateronasal, which when developed forms the lateral edge of the nostril. Additionally, a complete osteological description of the species type, Neoplecostomus microps (Steindachner, 1876), was performed. Also present some considerations about Neoplecostomus ribeirensis (rio Ribeira de Iguape basin), since it is most closely related to Isbrueckerichthys, that other cogenerics species / Mestre

Orientador: Daniel Carvalho / Coorientador: Javier Lobón-Cerviá / Banca: Katharina Esteves / Banca: Sandro Britto / Banca: Igor Paiva Ramos / Banca: Gilmar Bastos / Resumo: Os grandes rios Neotropicais, com seus canais principais, seus canais secundários, lagoas marginais conectados e isolados dos cursos de água apresentam uma elevada diversidade de habitats. A grande variedade de habitats proporciona a formação de gradientes ambientais espacialmente heterogêneos, considerados de suma importância para a biodiversidade. Uma diversidade ambiental é comumente encontrada em águas doces Neotropicais e, mais especificamente, na América do Sul, como por exemplo, nas bacias hidrográficas do Amazonas e do Paraná. Os compartimentos espaciais são de grande importância para o desenvolvimento do ciclo de vida das comunidades aquáticas, e diversos estudos têm enfatizado que lagoas marginais podem desempenhar um papel fundamental para a reprodução, alimentação e crescimento de inúmeras espécies de peixes e outros organismos aquáticos. Porém, pouco se sabe sobre a dinâmica desses organismos em sistemas lóticos e sistemas lênticos marginais e eventuais interações numa mesma escala temporal. O objetivo deste estudo foi analisar e comparar a estrutura dos organismos aquáticos e a dinâmica trófica das assembleias de peixes em um sistema lótico (canal principal do rio) versus um sistema lêntico contíguo (lagoa marginal), nas estações seca e chuvosa. Os locais selecionados para este estudo foi o canal principal do rio frente a uma lagoa marginal, na bacia do alto rio Paranapanema. É considerado um dos mais importantes tributários do alto rio Paraná, com sua nascente localizada na Serra da Paranapiacaba, no Estado de São Paulo, Sudeste Brasileiro. O conjunto de organismos aquáticos responsáveis pela produção primária e secundária, como o fitoplâncton, zooplâncton, macrófitas e macroinvertebrados mostraram algumas diferenças quanto a sua composição comparando a biota do canal principal do rio com aquela da lagoa marginal, bem como nas duas épocas do ano. De modo geral, riqueza maior de... / Abstract: The large Neotropical rivers, with their main channels, their secondary channels, oxbow lake connected and isolated from water courses have a high diversity of habitats. The large variety of habitats provides the formation of spatially heterogeneous environmental gradients, considered of great importance for biodiversity. An environmental diversity is commonly found in freshwater Neotropical, more specifically in South America, for example, in the basins of the Amazon and Paraná. Space compartments are of great importance for the development of life cycle of aquatic communities, and several studies suggest that lagoons can play a key role in reproduction, feeding and growth of numerous species of fish and other aquatic organisms. However, little is known about the dynamics of those bodies in river systems and oxbow lake systems and possible interactions in the same time scale. The objective of this study was to analyze and compare the structure of aquatic organisms and trophic dynamics of fish assemblages in a lotic system (main river channel) versus one contiguous lentic system (oxbow lake), in the dry and rainy seasons. The selected site for this study was the main river channel front to an oxbow lake, in the Upper Paranapanema River basin. It is considered one of the most important tributaries of the upper Paraná River, with its source located in the Paranapiacaba Mountain, State of São Paulo, Southeastern Brazil. The set of aquatic organisms responsible for primary and secondary production, such as phytoplankton, zooplankton, macrophytes and macroinvertebrates showed some differences in its composition compared to biota of the main river channel with that of the oxbow lake, as well as in the two seasons. In general, the higher rate richness occurred in the oxbow lake. The structure of fish assemblages also showed some differences when comparing the environments and periods of the year. A greater diversity of species in the main ... / Doutor

Halichoeres socialis Randall & Lobel, 2003, is the only wrasse species (Teleostei: Labridae) with a restricted distribution within the Caribbean Meso-American Barrier Reef (MABR), Central America. This study examined the early life history of H. socialis to gain insight into its natural history and to assess if any pattern in otolith microstructure could be linked to its endemism. The sagittal otoliths from 67 individuals (ranging 9.8–43.4mm SL) were analyzed to determine the daily age and increment profile. Results indicate that (1) H. socialis displays a typical “settlement mark”; (2) the pelagic larval duration (PLD) ranged from 22 to 32 (mean=27, n=59) days, which was similar to its congeners; and (3) the juvenile growth rate is 0.7mm/d, which was faster than most congeners. The endemism of H. socialis is not explained by its PLD. Alternatively, it is possible that larval behaviors (vertical migration and/or schooling) play a key factor in how H. socialis larvae are retained within the MABR region. / 2026-03-19T00:00:00Z

Cette étude archéologique et archéo-ichtyologique a pour but d’aborder une activité rarement décrite par les historiens : la pêche sur le littoral de l’Aquitaine romaine (Ier - IIIe siècle). Le renouvellement des informations, peu nombreuses sur ce sujet, nécessitait une approche archéo-ichtyologique, menée sur quatre sites archéologiques : Barzan (Charente-Maritime), Bordeaux et Biganos (Gironde), et un site de production de sauces et salaisons de poisson à Guéthary (Pyrénées-Atlantiques). Pour la première fois dans cette région, le matériel archéo-ichtyofaunique a été récolté selon des stratégies d’échantillonnage adaptées aux caractéristiques de chaque gisement, afin de disposer de données représentatives des espèces consommées. Ces données ont été confrontées aux sources écrites et figurées antiques et aux travaux plus récents d’époques moderne et contemporaine portant sur la pêche et l’écologie des écosystèmes concernés. Cette méthode comparative a permis d’éclairer des textes antiques quelquefois obscurs et d’émettre des hypothèses sur les techniques de pêche utilisées en fonction des espèces de poisson présentes sur les sites, de leur taille et de leur saison de capture. En fonction de la finalité économique (consommation de poisson frais ou transformation en sauces et salaisons), les spécificités de la pêche et les relations entre les milieux exploités et les techniques utilisées ont été étudiées. L’activité de pêche répondait à une adaptation aux milieux et aux espèces ciblées mais également à des critères économiques et culturels, propres à l’époque romaine. Les échanges entre les agglomérations étudiées ont été abordés afin de réfléchir sur l’approvisionnement de Bordeaux en poissons marins. Dans ce cadre, la portée économique de l’unique établissement à salaisons d’Aquitaine romaine, situé à Guéthary, a été discutée. La part de l’influence romaine dans le développement de cette production a été démontrée par la convergence de multiples données archéologiques et historiques. / The goal of this archaeological and archaeo-ichthyological study is to address an activity rarely described by historians: the fishing on the coast of Aquitaine during the Roman period (1st – 3rd century AD). The renewal of the information, few concerning this subject, required an archaeo-ichthyological study conducted on four archaeological sites: Barzan (Charente-Maritime), Bordeaux and Biganos (Gironde), and the salting installation of Guéthary (Pyrénées-Atlantiques). For the first time in this region, the fish bones remains were collected according to sampling strategies adapted to the characteristics of each archaeological site, in order to obtain representative data of the consumed fish species. These data were compared with ancient written and iconographic sources and with modern and contemporary works concerning the fishing and the ecology of the studied ecosystems. This comparative method allowed to clarify ancient texts, and to suggest hypothesis about the fishing techniques used thanks to the fish species discovered on the sites, their size and their season of capture. According to the economic purpose (fresh fish consumption or fish processing), the fishing specificities but also the connections between the exploited environments and the used techniques were studied. The fishing activity involved an adaptation to ecosystems targeted but also to economic and cultural criteria, specific to the Roman period. The exchanges between the studied sites were discussed in order to think about the supply of marine fishes to Bordeaux. In this context, the economic significance of the unique salting installation of Roman Aquitaine, situated in Guéthary, was discussed. The part of the Roman influence in the development of this production was demonstrated by the convergence of several archaeological and historical data.

Dentre os sistemas naturais de regiões tropicais e sub-tropicais destacam-se os ambientes aquáticos que são representados por diferentes tipos de \"habitats\" como rios, riachos e lagoas marginais. A bacia do rio Sorocaba é um exemplo destes sistemas, sendo constituída por ambientes variados e, portanto, por condições ecológicas distintas. Tendo em vista a necessidade de caracterizar tais \"habitats\" por meio de índice de integridade biótica (IBI) e de prover informações ecológicas nesta bacia, foi realizado um estudo limnológico e ictiológico em doze tributários do rio Sorocaba de quatro ordens diferentes. Foram realizadas coletas para a avaliação das variáveis físicas, químicas e biológicas nas épocas de cheia e seca, nos anos de 1999 e 2000. Onze variáveis relacionadas à organização e saúde da comunidade de peixes foram avaliadas para análise do índice de integridade biótica dos \"habitats\" aquáticos em estudo, sendo essas variáveis selecionadas de maneira a detectar impactos sobre a estrutura da comunidade. Para tanto, verificou-se a riqueza e a abundância total das espécies, além da intolerância e categoria trófica dos indivíduos. Os resultados indicaram que a organização e a saúde da comunidade de peixes foram as variáveis mais importantes para composição do índice de integridade biótica nas três diferentes ordens de rio estudadas (2ª, 3ª e 4ª). De maneira geral, a bacia do rio Sorocaba apresentou-se alterada em relação aos padrões estabelecidos para comunidade íctica nesta última década, o que é indicativo de certo grau de degradação no sistema. / Tropical and sub-tropical rivers distinguish themselves among the aquatic systems in producing different types of habitats such as rivers, stream, creeks and floodplain lakes. The Sorocaba river in the State of São Paulo, Brazil, is an example of this type of system constituted by a variety environments and, hence producing distinct ecological conditions. A limnological and ictiological study of 12 tributaries of Sorocaba river four different stream orders was conducted to characterize these habitats in relation to the index of biological integrity and also to provide ecological information about the environmental conditions on the hydrographic basin. Data on physical, chemical and biological variables were obtained in dry and wet seasons during years 1999 and 2000. Eleven variables related to the organization and integrity of the fishes communityes were evaluated for the analysis of biotic integrity index of the aquatic habitats under study. These variables were selected to detected any environmental impacts on the structure of communities. The species richness and total abundance of the species as well as the intolerance and trophic category of individual were focused for this purpose. The results indicate that the organization and well-being of the communities were the most important variables, in determining the biotic integrity index in three higher stream orders, namely 2nd, 3rd and the 4th. In general, the Sorocaba river showed alterations in relation to the established patterns for ictic communities have been indicating of a certain degree of degradation in the system.

Common dolphins (genus Delphinus) are poorly understood within New Zealand waters. Prior to this study, most information relating to the taxonomy, population structure, diet and pollutant loads of this genus relied upon untested assumptions. Furthermore, factors affecting the occurrence, demographics and habitat use of common dolphins in the Hauraki Gulf remained unknown. This lack of empirical data has resulted in the inadequate recognition and management of New Zealand Delphinus. Inappropriately classified by the New Zealand Threat Classification System, the anthropogenic impacts that affect this genus have clearly been overlooked. The present study examines behaviour of common dolphins in the Hauraki Gulf and details analyses undertaken on tissue samples collected from around New Zealand. Results detailed here challenge many of the untested assumptions about this genus within New Zealand waters. The taxonomy of New Zealand common dolphins was assessed using 92 samples analysed for 577 base pairs (bps) of the mtDNA control region (D-loop). New Zealand samples were compared with 177 published sequences from eight other populations from around the world. New Zealand Delphinus exhibited a high genetic variability, sharing haplotypes with both short- (D. delphis) and long-beaked (D. capensis) populations. Indeed, the New Zealand population showed significant genetic differentiation when compared with most other populations world-wide. Furthermore, intrapopulation analyses revealed significant genetic differentiation between Hauraki Gulf individuals and other common dolphins sampled within New Zealand waters. Results suggest habitat choice and site fidelity may play a role in shaping the fragmented population structure of New Zealand Delphinus. Data relating to the occurrence and demographics of common dolphins in the Hauraki Gulf region were collected during boat-based surveys between February 2002 and January 2005. In total, 719 independent encounters, involving one to > 300 common dolphins were recorded. Dolphin presence was significantly affected by month, latitude and depth. Group size varied significantly by month, season, depth, sea surface temperature (SST) and latitude, and was highly skewed towards smaller groups comprising fewer than 50 animals. Calves were observed throughout the year but were most prevalent in the austral summer months of December and January. Group composition was significantly affected by month, season, depth and SST. The yearround occurrence and social organisation of Delphinus in Hauraki Gulf waters suggest this region is an important nursery and potential calving area. The effects of diel, season, depth, sea surface temperature, and group size and composition on dolphin behaviour were investigated using activity budgets. Foraging and social were the most and least frequently observed behaviours, respectively. A correlation between group size and behaviour was evident, although behaviour did not vary with the composition of dolphin groups. Resting, milling and socialising animals were more frequently observed in smaller groups. Foraging behaviour was prevalent in both small and large groups, suggesting foraging plasticity exists within this population. Behaviour differed between single- and multi-species groups, with foraging more frequent in mixed-species aggregations, indicating the primary mechanism for association is likely prey-related. Stomach contents analysed for forty-two stranded and eleven commercially by-caught individuals collected from around North Island, New Zealand between 1997 and 2006, revealed arrow squid (Nototodarus spp.), jack mackerel (Trachurus spp.) and anchovy (Engraulis australis) as the most prevalent prey. Stranded individuals and dolphins bycaught within neritic waters fed on both neritic and oceanic prey. Moreover, a mixed prey composition was evident in the diet of common dolphins by-caught in oceanic waters, suggesting inshore/offshore movements of New Zealand Delphinus on a diel basis. Additionally, prey differences were also evident in the stomach contents of common dolphins sampled from within the Hauraki Gulf. Trace elements, polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticide levels were determined in five stranded and fourteen by-caught Delphinus sampled from around New Zealand between 1999 and 2005. Generally, levels of trace elements were low. However, concentrations of OC pesticides were similar in range to those previously reported for Hector’s (Cephalorhyncus hectori) and common bottlenose dolphins (Tursiops truncatus). Organochlorine pesticides dieldrin, hexachlorobenzene (HCB), o,p’-DDT and p,p’-DDE were present at the highest concentrations. Markov chain models were used to assess the impact of tourism activities on Delphinus within the Hauraki Gulf. Foraging and resting bouts were significantly disrupted by boat interactions. Both the duration of bouts and the time spent in these two behavioural states decreased during boat interactions. Additionally, foraging dolphins took significantly longer to return to their initial behavioural state in the presence of a tour boat. Impacts identified are similar to those previously reported for the common bottlenose dolphin, a coastal species typically considered to be more susceptible to cumulative anthropogenic impacts. Data presented here reveal the nature and apparent susceptibility of New Zealand common dolphins to human-induced impacts, namely fisheries by-catch, pollution and tourism. This in conjunction with taxonomic uncertainty, lack of abundance estimates and the year-round use of inshore waters for feeding, clearly warrants immediate attention from managers. Furthermore, the current threat classification of New Zealand Delphinus should be reconsidered in light of population uncertainties, and in view of the susceptibly to human-induced impacts revealed by the present study.

Common dolphins (genus Delphinus) are poorly understood within New Zealand waters. Prior to this study, most information relating to the taxonomy, population structure, diet and pollutant loads of this genus relied upon untested assumptions. Furthermore, factors affecting the occurrence, demographics and habitat use of common dolphins in the Hauraki Gulf remained unknown. This lack of empirical data has resulted in the inadequate recognition and management of New Zealand Delphinus. Inappropriately classified by the New Zealand Threat Classification System, the anthropogenic impacts that affect this genus have clearly been overlooked. The present study examines behaviour of common dolphins in the Hauraki Gulf and details analyses undertaken on tissue samples collected from around New Zealand. Results detailed here challenge many of the untested assumptions about this genus within New Zealand waters. The taxonomy of New Zealand common dolphins was assessed using 92 samples analysed for 577 base pairs (bps) of the mtDNA control region (D-loop). New Zealand samples were compared with 177 published sequences from eight other populations from around the world. New Zealand Delphinus exhibited a high genetic variability, sharing haplotypes with both short- (D. delphis) and long-beaked (D. capensis) populations. Indeed, the New Zealand population showed significant genetic differentiation when compared with most other populations world-wide. Furthermore, intrapopulation analyses revealed significant genetic differentiation between Hauraki Gulf individuals and other common dolphins sampled within New Zealand waters. Results suggest habitat choice and site fidelity may play a role in shaping the fragmented population structure of New Zealand Delphinus. Data relating to the occurrence and demographics of common dolphins in the Hauraki Gulf region were collected during boat-based surveys between February 2002 and January 2005. In total, 719 independent encounters, involving one to > 300 common dolphins were recorded. Dolphin presence was significantly affected by month, latitude and depth. Group size varied significantly by month, season, depth, sea surface temperature (SST) and latitude, and was highly skewed towards smaller groups comprising fewer than 50 animals. Calves were observed throughout the year but were most prevalent in the austral summer months of December and January. Group composition was significantly affected by month, season, depth and SST. The yearround occurrence and social organisation of Delphinus in Hauraki Gulf waters suggest this region is an important nursery and potential calving area. The effects of diel, season, depth, sea surface temperature, and group size and composition on dolphin behaviour were investigated using activity budgets. Foraging and social were the most and least frequently observed behaviours, respectively. A correlation between group size and behaviour was evident, although behaviour did not vary with the composition of dolphin groups. Resting, milling and socialising animals were more frequently observed in smaller groups. Foraging behaviour was prevalent in both small and large groups, suggesting foraging plasticity exists within this population. Behaviour differed between single- and multi-species groups, with foraging more frequent in mixed-species aggregations, indicating the primary mechanism for association is likely prey-related. Stomach contents analysed for forty-two stranded and eleven commercially by-caught individuals collected from around North Island, New Zealand between 1997 and 2006, revealed arrow squid (Nototodarus spp.), jack mackerel (Trachurus spp.) and anchovy (Engraulis australis) as the most prevalent prey. Stranded individuals and dolphins bycaught within neritic waters fed on both neritic and oceanic prey. Moreover, a mixed prey composition was evident in the diet of common dolphins by-caught in oceanic waters, suggesting inshore/offshore movements of New Zealand Delphinus on a diel basis. Additionally, prey differences were also evident in the stomach contents of common dolphins sampled from within the Hauraki Gulf. Trace elements, polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticide levels were determined in five stranded and fourteen by-caught Delphinus sampled from around New Zealand between 1999 and 2005. Generally, levels of trace elements were low. However, concentrations of OC pesticides were similar in range to those previously reported for Hector’s (Cephalorhyncus hectori) and common bottlenose dolphins (Tursiops truncatus). Organochlorine pesticides dieldrin, hexachlorobenzene (HCB), o,p’-DDT and p,p’-DDE were present at the highest concentrations. Markov chain models were used to assess the impact of tourism activities on Delphinus within the Hauraki Gulf. Foraging and resting bouts were significantly disrupted by boat interactions. Both the duration of bouts and the time spent in these two behavioural states decreased during boat interactions. Additionally, foraging dolphins took significantly longer to return to their initial behavioural state in the presence of a tour boat. Impacts identified are similar to those previously reported for the common bottlenose dolphin, a coastal species typically considered to be more susceptible to cumulative anthropogenic impacts. Data presented here reveal the nature and apparent susceptibility of New Zealand common dolphins to human-induced impacts, namely fisheries by-catch, pollution and tourism. This in conjunction with taxonomic uncertainty, lack of abundance estimates and the year-round use of inshore waters for feeding, clearly warrants immediate attention from managers. Furthermore, the current threat classification of New Zealand Delphinus should be reconsidered in light of population uncertainties, and in view of the susceptibly to human-induced impacts revealed by the present study.

Common dolphins (genus Delphinus) are poorly understood within New Zealand waters. Prior to this study, most information relating to the taxonomy, population structure, diet and pollutant loads of this genus relied upon untested assumptions. Furthermore, factors affecting the occurrence, demographics and habitat use of common dolphins in the Hauraki Gulf remained unknown. This lack of empirical data has resulted in the inadequate recognition and management of New Zealand Delphinus. Inappropriately classified by the New Zealand Threat Classification System, the anthropogenic impacts that affect this genus have clearly been overlooked. The present study examines behaviour of common dolphins in the Hauraki Gulf and details analyses undertaken on tissue samples collected from around New Zealand. Results detailed here challenge many of the untested assumptions about this genus within New Zealand waters. The taxonomy of New Zealand common dolphins was assessed using 92 samples analysed for 577 base pairs (bps) of the mtDNA control region (D-loop). New Zealand samples were compared with 177 published sequences from eight other populations from around the world. New Zealand Delphinus exhibited a high genetic variability, sharing haplotypes with both short- (D. delphis) and long-beaked (D. capensis) populations. Indeed, the New Zealand population showed significant genetic differentiation when compared with most other populations world-wide. Furthermore, intrapopulation analyses revealed significant genetic differentiation between Hauraki Gulf individuals and other common dolphins sampled within New Zealand waters. Results suggest habitat choice and site fidelity may play a role in shaping the fragmented population structure of New Zealand Delphinus. Data relating to the occurrence and demographics of common dolphins in the Hauraki Gulf region were collected during boat-based surveys between February 2002 and January 2005. In total, 719 independent encounters, involving one to > 300 common dolphins were recorded. Dolphin presence was significantly affected by month, latitude and depth. Group size varied significantly by month, season, depth, sea surface temperature (SST) and latitude, and was highly skewed towards smaller groups comprising fewer than 50 animals. Calves were observed throughout the year but were most prevalent in the austral summer months of December and January. Group composition was significantly affected by month, season, depth and SST. The yearround occurrence and social organisation of Delphinus in Hauraki Gulf waters suggest this region is an important nursery and potential calving area. The effects of diel, season, depth, sea surface temperature, and group size and composition on dolphin behaviour were investigated using activity budgets. Foraging and social were the most and least frequently observed behaviours, respectively. A correlation between group size and behaviour was evident, although behaviour did not vary with the composition of dolphin groups. Resting, milling and socialising animals were more frequently observed in smaller groups. Foraging behaviour was prevalent in both small and large groups, suggesting foraging plasticity exists within this population. Behaviour differed between single- and multi-species groups, with foraging more frequent in mixed-species aggregations, indicating the primary mechanism for association is likely prey-related. Stomach contents analysed for forty-two stranded and eleven commercially by-caught individuals collected from around North Island, New Zealand between 1997 and 2006, revealed arrow squid (Nototodarus spp.), jack mackerel (Trachurus spp.) and anchovy (Engraulis australis) as the most prevalent prey. Stranded individuals and dolphins bycaught within neritic waters fed on both neritic and oceanic prey. Moreover, a mixed prey composition was evident in the diet of common dolphins by-caught in oceanic waters, suggesting inshore/offshore movements of New Zealand Delphinus on a diel basis. Additionally, prey differences were also evident in the stomach contents of common dolphins sampled from within the Hauraki Gulf. Trace elements, polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticide levels were determined in five stranded and fourteen by-caught Delphinus sampled from around New Zealand between 1999 and 2005. Generally, levels of trace elements were low. However, concentrations of OC pesticides were similar in range to those previously reported for Hector’s (Cephalorhyncus hectori) and common bottlenose dolphins (Tursiops truncatus). Organochlorine pesticides dieldrin, hexachlorobenzene (HCB), o,p’-DDT and p,p’-DDE were present at the highest concentrations. Markov chain models were used to assess the impact of tourism activities on Delphinus within the Hauraki Gulf. Foraging and resting bouts were significantly disrupted by boat interactions. Both the duration of bouts and the time spent in these two behavioural states decreased during boat interactions. Additionally, foraging dolphins took significantly longer to return to their initial behavioural state in the presence of a tour boat. Impacts identified are similar to those previously reported for the common bottlenose dolphin, a coastal species typically considered to be more susceptible to cumulative anthropogenic impacts. Data presented here reveal the nature and apparent susceptibility of New Zealand common dolphins to human-induced impacts, namely fisheries by-catch, pollution and tourism. This in conjunction with taxonomic uncertainty, lack of abundance estimates and the year-round use of inshore waters for feeding, clearly warrants immediate attention from managers. Furthermore, the current threat classification of New Zealand Delphinus should be reconsidered in light of population uncertainties, and in view of the susceptibly to human-induced impacts revealed by the present study.

Common dolphins (genus Delphinus) are poorly understood within New Zealand waters. Prior to this study, most information relating to the taxonomy, population structure, diet and pollutant loads of this genus relied upon untested assumptions. Furthermore, factors affecting the occurrence, demographics and habitat use of common dolphins in the Hauraki Gulf remained unknown. This lack of empirical data has resulted in the inadequate recognition and management of New Zealand Delphinus. Inappropriately classified by the New Zealand Threat Classification System, the anthropogenic impacts that affect this genus have clearly been overlooked. The present study examines behaviour of common dolphins in the Hauraki Gulf and details analyses undertaken on tissue samples collected from around New Zealand. Results detailed here challenge many of the untested assumptions about this genus within New Zealand waters. The taxonomy of New Zealand common dolphins was assessed using 92 samples analysed for 577 base pairs (bps) of the mtDNA control region (D-loop). New Zealand samples were compared with 177 published sequences from eight other populations from around the world. New Zealand Delphinus exhibited a high genetic variability, sharing haplotypes with both short- (D. delphis) and long-beaked (D. capensis) populations. Indeed, the New Zealand population showed significant genetic differentiation when compared with most other populations world-wide. Furthermore, intrapopulation analyses revealed significant genetic differentiation between Hauraki Gulf individuals and other common dolphins sampled within New Zealand waters. Results suggest habitat choice and site fidelity may play a role in shaping the fragmented population structure of New Zealand Delphinus. Data relating to the occurrence and demographics of common dolphins in the Hauraki Gulf region were collected during boat-based surveys between February 2002 and January 2005. In total, 719 independent encounters, involving one to > 300 common dolphins were recorded. Dolphin presence was significantly affected by month, latitude and depth. Group size varied significantly by month, season, depth, sea surface temperature (SST) and latitude, and was highly skewed towards smaller groups comprising fewer than 50 animals. Calves were observed throughout the year but were most prevalent in the austral summer months of December and January. Group composition was significantly affected by month, season, depth and SST. The yearround occurrence and social organisation of Delphinus in Hauraki Gulf waters suggest this region is an important nursery and potential calving area. The effects of diel, season, depth, sea surface temperature, and group size and composition on dolphin behaviour were investigated using activity budgets. Foraging and social were the most and least frequently observed behaviours, respectively. A correlation between group size and behaviour was evident, although behaviour did not vary with the composition of dolphin groups. Resting, milling and socialising animals were more frequently observed in smaller groups. Foraging behaviour was prevalent in both small and large groups, suggesting foraging plasticity exists within this population. Behaviour differed between single- and multi-species groups, with foraging more frequent in mixed-species aggregations, indicating the primary mechanism for association is likely prey-related. Stomach contents analysed for forty-two stranded and eleven commercially by-caught individuals collected from around North Island, New Zealand between 1997 and 2006, revealed arrow squid (Nototodarus spp.), jack mackerel (Trachurus spp.) and anchovy (Engraulis australis) as the most prevalent prey. Stranded individuals and dolphins bycaught within neritic waters fed on both neritic and oceanic prey. Moreover, a mixed prey composition was evident in the diet of common dolphins by-caught in oceanic waters, suggesting inshore/offshore movements of New Zealand Delphinus on a diel basis. Additionally, prey differences were also evident in the stomach contents of common dolphins sampled from within the Hauraki Gulf. Trace elements, polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticide levels were determined in five stranded and fourteen by-caught Delphinus sampled from around New Zealand between 1999 and 2005. Generally, levels of trace elements were low. However, concentrations of OC pesticides were similar in range to those previously reported for Hector’s (Cephalorhyncus hectori) and common bottlenose dolphins (Tursiops truncatus). Organochlorine pesticides dieldrin, hexachlorobenzene (HCB), o,p’-DDT and p,p’-DDE were present at the highest concentrations. Markov chain models were used to assess the impact of tourism activities on Delphinus within the Hauraki Gulf. Foraging and resting bouts were significantly disrupted by boat interactions. Both the duration of bouts and the time spent in these two behavioural states decreased during boat interactions. Additionally, foraging dolphins took significantly longer to return to their initial behavioural state in the presence of a tour boat. Impacts identified are similar to those previously reported for the common bottlenose dolphin, a coastal species typically considered to be more susceptible to cumulative anthropogenic impacts. Data presented here reveal the nature and apparent susceptibility of New Zealand common dolphins to human-induced impacts, namely fisheries by-catch, pollution and tourism. This in conjunction with taxonomic uncertainty, lack of abundance estimates and the year-round use of inshore waters for feeding, clearly warrants immediate attention from managers. Furthermore, the current threat classification of New Zealand Delphinus should be reconsidered in light of population uncertainties, and in view of the susceptibly to human-induced impacts revealed by the present study.