RESUMO

The gonad development and reproductive aspects of Hemiramphus brasiliensis from the coastal waters of Rio Grande do Norte, Brazil were verified. This paper presents data on the length-weight relationship, sex ratio, length at first sexual maturity, gonad development, reproductive period and fecundity of H. brasiliensis. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was 20.8 cm and that of females was 21.5 cm. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. brasiliensis showed six phases of oocyte development and four phases of spermatocyte development. The batch fecundity of this species is 1153 (± 258.22) oocytes for 50 g body weight of female. The microscopic characteristics of gonad development indicate that H. brasiliensis is a multiple spawner, with active reproductive period during the months of January to June and October. The reproductive period of this species is independent of the rainy period of the region.

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This work presents information regarding the biology and state of conservation of an endangered annual fish Hypsolebias antenori. Fish were captured from small seasonal pools located in Northeastern Brazil. The total body length, body mass, sex ratio, first sexual maturity were investigated. The sampled population showed sexual dimorphism. There was a predominance of females (60%) over males (40%) with a sex ratio of 1: 1.4 and males were bigger and heavier than the females. Amplitude of total length of males ranged from 2.6 to 7.1cm (4.1 ± 1.15) and that of females from 2.2 to 5.4 cm (3.6 ± 0.9). Amplitude of body mass of males varied from 0.25 to 7 g (1.3 g ± 1.4) and that of females from 0.12 to 2.1g (0.7 g ± 0.5). The total weight-length equation of males was Wt = 0.0108Lt3.172 with r = 0.9826 and of females was Wt = 0.0122Lt3.0114 with r = 0.9608. Females attained first sexual maturity at 3.2 cm (± 0.25) total length and males at 3.3 cm (± 0.08) total length. All temporary pools surveyed in Northeastern Brazil were in a high degree of degradation, suffering due to anthropogenic action. Reduced rainfall resulting from global climate change prevents the filling up of these pools, thus preventing the completion of the reproductive cycle of annual fishes. One factor hindering development of conservation strategies is limited literature on biology and conservation status of annual fishes. There is a need for conservation measures to protect annual fish populations, especially creation of protected areas in the Brazilian semiarid region.

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The epipelagic flyingfish, Hirundichthys affinis is a major artisanal fishery resource from the Northeastern coastal waters of Brazil. However, biological information about this species has been poorly documented. This paper presents data on the length-weight relationship, sex ratio, length at first sexual maturity, gonadal development and fecundity of H. affinis sampled from the coastal waters of Rio Grande do Norte, Brazil. The total body length and weight for both sexes ranged from 23.4 to 29.4 cm and from 89 to 188g, respectively. The allometric coefficient of males was 2.208 and that of females was 2.985, indicating negatively allometric growth. The sex ratio was 1M:1.6F thus differing from the expected ratio of 1:1 (χ2 = 18.63). The total length at first sexual maturity was estimated at 27.3 cm for males and 27.1 cm for females. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. affinis showed seven phases of oocyte development and four phases of spermatocyte development. The mean absolute fecundity was 9092 vitelogenic oocytes. Spawning occurred during the months of March to July. The microscopic descriptions of the stages of gonad maturation indicate that the study area is an important spawning ground of H. affinis.

Assuntos

RESUMO

The gonad development and reproductive aspects of Hemiramphus brasiliensis from the coastal waters of Rio Grande do Norte, Brazil were verified. This paper presents data on the length-weight relationship, sex ratio, length at first sexual maturity, gonad development, reproductive period and fecundity of H. brasiliensis. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was 20.8 cm and that of females was 21.5 cm. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. brasiliensis showed six phases of oocyte development and four phases of spermatocyte development. The batch fecundity of this species is 1153 (±258.22) oocytes for 50 g body weight of female. The microscopic characteristics of gonad development indicate that H. brasiliensis is a multiple spawner, with active reproductive period during the months of January to June and October. The reproductive period of this species is independent of the rainy period of the region.(AU)

O desenvolvimento das gônadas e os aspectos reprodutivos de Hemiramphus brasiliensis nas águas costeiras do Rio Grande do Norte, Brasil foram verificados. Este trabalho apresenta dados sobre a relação peso-comprimento, proporção sexual, comprimento de primeira maturação sexual, desenvolvimento gonadal, período reprodutivo e fecundidade de H. brasiliensis. As fêmeas de H. brasiliensis predominam na população amostrada e foram maiores em tamanho do que os machos. O comprimento da primeira maturação sexual dos machos foi de 20,8 cm e das fêmeas foi de 21,5 cm. As características macroscópicas das gônadas indicam quatro estádios de maturação. Estudos histológicos de gônadas de H. brasiliensis mostraram seis fases de desenvolvimento do ovócito e quatro fases de desenvolvimento de espermatócitos. A fecundidade por lote desta espécie foi 1,153 (± 258,22) ovócitos por 50 g de peso corporal da fêmea. As características microscópicas de desenvolvimento das gônadas indicam que H. brasiliensis apresenta desova múltipla, com um período de atividade reprodutiva nos meses de janeiro a junho e outubro. O período reprodutivo de H. brasiliensis é independente das chuvas da região.(AU)

Assuntos

RESUMO

This work presents information regarding the biology and state of conservation of an endangered annual fish Hypsolebias antenori. Fish were captured from small seasonal pools located in Northeastern Brazil. The total body length, body mass, sex ratio, first sexual maturity were investigated. The sampled population showed sexual dimorphism. There was a predominance of females (60%) over males (40%) with a sex ratio of 1: 1.4 and males were bigger and heavier than the females. Amplitude of total length of males ranged from 2.6 to 7.1cm (4.1±1.15) and that of females from 2.2 to 5.4cm (3.6±0.9). Amplitude of body mass of males varied from 0.25 to 7g (1.3g±1.4) and that of females from 0.12 to 2.1g (0.7g±0.5). The total weight-length equation of males was Wt=0.0108Lt3.172 with r = 0.9826 and of females was Wt=0.0122Lt3.0114 with r = 0.9608. Females attained first sexual maturity at 3.2 cm (±0.25) total length and males at 3.3 cm (±0.08) total length. All temporary pools surveyed in Northeastern Brazil were in a high degree of degradation, suffering due to anthropogenic action. Reduced rainfall resulting from global climate change prevents the filling up of these pools, thus preventing the completion of the reproductive cycle of annual fishes. One factor hindering development of conservation strategies is limited literature on biology and conservation status of annual fishes. There is a need for conservation measures to protect annual fish populations, especially creation of protected areas in the Brazilian semiarid region.(AU)

Este trabalho apresenta informações sobre a biologia e estado de conservação de Hypsolebias antenori, um peixe anual ameaçado. Os peixes foram capturados em pequenas poças temporárias localizadas no Nordeste do Brasil. O comprimento total, peso total, proporção sexual e a primeira maturação sexual foram investigados. A espécie em estudo apresentou dimorfismo sexual bem evidente. Houve um predomínio de fêmeas (60%) sobre os machos (40%), com uma razão sexual de 1M: 1,4F. Os machos foram significativamente maiores e mais pesados do que as fêmeas. A amplitude do comprimento total dos machos variou de 2,6 a 7,1 centímetros (4,1 ± 1,15) e as fêmeas de 2,2 a 5,4 centímetros (3,6 ± 0,9). A amplitude de peso dos machos variou de 0,25 a 7 g (1,4 ± 1,3 g), enquanto que as fêmeas de 0,12 a 2,1 g (0,5 ± 0,7 g). A equação da relação peso total/comprimento dos machos foi Wt = 0.0108Lt3.172 com r = 0,9826 e para fêmeas foi Wt = 0.0122Lt3.0114 com r = 0,9608. As fêmeas alcançaram a primeira maturação sexual com 3,2 cm ( ± 0,25) de comprimento total e os machos com 3,3 centímetros ( ± 0,08 ) de comprimento total. Todas as poças temporárias amostradas neste trabalho estavam em um alto grau de degradação, principalmente devido à ação antrópica. Observamos que diminuição das chuvas e a desertificação decorrente das mudanças climáticas globais que também são alarmantes e poderão impedir a conclusão do ciclo reprodutivo dos peixes anuais. As informações sobre a biologia e o estado de conservação dos peixes anuais ainda são limitadas, portanto há uma grande necessidade estudos e de medidas de conservação para proteger as populações de peixes anuais, entre elas especialmente a criação de áreas proteção nos ambientes aquáticos efêmeros do semiárido brasileiro.(AU)

Assuntos

RESUMO

The epipelagic flyingfish, Hirundichthys affinis is a major artisanal fishery resource from the Northeastern coastal waters of Brazil. However, biological information about this species has been poorly documented. This paper presents data on the length-weight relationship, sex ratio, length at first sexual maturity, gonadal development and fecundity of H. affinis sampled from the coastal waters of Rio Grande do Norte, Brazil. The total body length and weight for both sexes ranged from 23.4 to 29.4 cm and from 89 to 188g, respectively. The allometric coefficient of males was 2.208 and that of females was 2.985, indicating negatively allometric growth. The sex ratio was 1M:1.6F thus differing from the expected ratio of 1:1 (χ2 = 18.63). The total length at first sexual maturity was estimated at 27.3 cm for males and 27.1 cm for females. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. affinis showed seven phases of oocyte development and four phases of spermatocyte development. The mean absolute fecundity was 9092 vitelogenic oocytes. Spawning occurred during the months of March to July. The microscopic descriptions of the stages of gonad maturation indicate that the study area is an important spawning ground of H. affinis.(AU)

O peixe epipelágico voador, Hirundichthys affinis é um importante recurso de pesca artesanal das águas costeiras do Nordeste do Brasil. No entanto, as informações biológicas sobre esta espécie tem sido pouco documentada. Este trabalho apresenta dados sobre a relação peso-comprimento, proporção sexual, comprimento de primeira maturação sexual, desenvolvimento gonadal e fecundidade de H. affinis amostrados das águas costeiras do Rio Grande do Norte, Brasil. O comprimento total e o peso total de ambos os sexos variaram 23,4-29,4 cm, e de 89 a 188g, respectivamente. O coeficiente alométrico dos machos foi de 2,208 e o de fêmeas foi 2,985, indicando um crescimento alométrico negativo. A proporção entre os sexos foi 1M:1.6 F, diferindo da proporção esperada de 1:1 (χ2 = 18.63). O comprimento total da primeira maturação sexual foi estimado em 27,3 centímetros para os machos e 27,1 cm para as fêmeas. As características macroscópicas das gônadas indicaram quatro estádios de maturação. Estudos histológicos das gônadas de H. affinis mostram sete fases de desenvolvimento do ovócito e quatro fases de desenvolvimento do espermatócito. A fecundidade absoluta média foi de 9.092 ovócitos vitelogênicos. A desova ocorreu durante os meses de março a julho. As descrições microscópicas dos estágios de maturação gonadal indicam que a área de estudo é uma importante área de desova de H. affinis.(AU)

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RESUMO

The red hybrid tilapia, Oreochromis niloticus (Linnaeus, 1758) x O. mossambicus (Peters, 1852) is a fertile hybrid used in the semi-intensive level of fish culture in the Northeast of Brazil. It is a territorial cichlid and is highly aggressive towards conspecifics during the breeding season. The purpose of this study was to investigate and describe the aggressive behaviour displayed by the males of this hybrid in non-reproductive and reproductive contexts. Behavioural observations revealed that aggression displayed by the reproductive males of red hybrid tilapia included threatening, undulation, parallel, lateral and frontal attacks, chasing, escape and submission. Possession of a territory influenced male aggressiveness, which was more intense in their own territory than that observed in a neutral situation. The males built nests, irrespective of female presence. All the behavioural patterns were in accordance with those previously described for one parental species, the Nile tilapia, O. niloticus.

O híbrido vermelho de tilápia Oreochromis niloticus (Linnaeus, 1758) x O. mossambicus (Peters, 1852) é um híbrido fértil utilizado na piscicultura numa escala semi-intensiva no Nordeste brasileiro. É um ciclídeo territorial e altamente agressivo frente a coespecíficos na época reprodutiva. O objetivo deste estudo foi investigar e descrever os comportamentos agressivos exibidos pelos machos deste híbrido em contextos não-reprodutivos e reprodutivos. As observações comportamentais mostraram que as agressões exibidas pelos machos de híbrido vermelho de tilápia incluíram ameaça, ondulação, confronto paralelo, lateral e frontal, perseguição, fuga e submissão. A posse do território influenciou a agressividade dos machos, cuja intensidade foi maior no próprio território em relação àquela observada em situação neutra. Os ninhos foram escavados pelos machos independente da presença das fêmeas. Todos os padrões comportamentais descritos estavam de acordo com os padrões previamente descritos para uma das espécies parentais, a Tilápia do Nilo, O. niloticus.

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RESUMO

The species, Pterophyllum scalare distinguishes itself by its breeding behavior, involving competition for territory, sexual partners, courtship and parental care. The purpose of this study was to identify the mating system adopted by this species of fish. Twenty males and twenty females were observed under semi-natural and experimental conditions to test the hypothesis of serial monogamy. Under semi-natural conditions, after the third breeding cycle, the couples changed mates. Under experimental conditions, the couples changed partners after the first breeding cycle. Under experimental conditions, mate recognition was investigated through the preference of the females, indicated by the time they spent with the males. The females were available or not for courtship from new males, depending on their aggressiveness or submission. The larger and more aggressive males obtained new mating opportunities while the submissive males were rejected by the females. The mated fish were aggressive towards intruders in the presence of the mate, protecting their pair bond. In the interval between breeding cycles, the couples did not display aggression towards intruders, confirming the hypothesis of serial monogamy. Best mate selection by the females and the opportunity of new matings for both sexes influenced the reproductive success of this species.

Assuntos

RESUMO

The species, Pterophyllum scalare distinguishes itself by its breeding behavior, involving competition for territory, sexual partners, courtship and parental care. The purpose of this study was to identify the mating system adopted by this species of fish. Twenty males and twenty females were observed under semi-natural and experimental conditions to test the hypothesis of serial monogamy. Under semi-natural conditions, after the third breeding cycle, the couples changed mates. Under experimental conditions, the couples changed partners after the first breeding cycle. Under experimental conditions, mate recognition was investigated through the preference of the females, indicated by the time they spent with the males. The females were available or not for courtship from new males, depending on their aggressiveness or submission. The larger and more aggressive males obtained new mating opportunities while the submissive males were rejected by the females. The mated fish were aggressive towards intruders in the presence of the mate, protecting their pair bond. In the interval between breeding cycles, the couples did not display aggression towards intruders, confirming the hypothesis of serial monogamy. Best mate selection by the females and the opportunity of new matings for both sexes influenced the reproductive success of this species.

A espécie Pterophyllum scalare se destaca pela complexidade de seu comportamento reprodutivo, envolvendo competição por território e parceiros sexuais, corte, acasalamento e cuidado parental. Este trabalho teve como objetivo identificar o tipo de sistema de acasalamento adotado pelos peixes desta espécie. Vinte machos e vinte fêmeas foram observados nas situações seminatural e experimental para testar a hipótese de monogamia serial. Em situação seminatural, após o terceiro ciclo reprodutivo, os casais mudaram de parceiros, enquanto que, em situação experimental, os casais mudaram de parceiros a partir do primeiro ciclo reprodutivo. Em situação experimental foi investigado o reconhecimento do parceiro, pela permanência das fêmeas que se mostraram disponíveis ou não à corte de novos machos, em função da agressividade e submissão deles. Machos maiores e mais agressivos obtiveram novas oportunidades de acasalamento e machos submissos foram rejeitados pelas fêmeas. Os peixes acasalados foram agressivos a intrusos na presença do parceiro, protegendo a ligação do par. No intervalo entre os ciclos reprodutivos, os pares não mostraram agressão a intrusos, confirmando a hipótese de monogamia serial. A escolha do melhor parceiro pelas fêmeas e a oportunidade de novos acasalamentos para ambos os sexos influenciaram o sucesso reprodutivo desta espécie.

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RESUMO

The red hybrid tilapia, Oreochromis niloticus (Linnaeus, 1758) x O. mossambicus (Peters, 1852) is a fertile hybrid used in the semi-intensive level of fish culture in the Northeast of Brazil. It is a territorial cichlid and is highly aggressive towards conspecifics during the breeding season. The purpose of this study was to investigate and describe the aggressive behaviour displayed by the males of this hybrid in non-reproductive and reproductive contexts. Behavioural observations revealed that aggression displayed by the reproductive males of red hybrid tilapia included threatening, undulation, parallel, lateral and frontal attacks, chasing, escape and submission. Possession of a territory influenced male aggressiveness, which was more intense in their own territory than that observed in a neutral situation. The males built nests, irrespective of female presence. All the behavioural patterns were in accordance with those previously described for one parental species, the Nile tilapia, O. niloticus.

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Dominance status among female marmosets is reflected in agonistic behavior and ovarian function. Socially dominant females receive submissive behavior from subordinates, while exhibiting normal ovulatory function. Subordinate females, however, receive agonistic behavior from dominants, while exhibiting reduced or absent ovulatory function. Such disparity in female fertility is not absolute, and groups with two breeding females have been described. The data reported here were obtained from 8 female-female pairs of captive female marmosets, each housed with a single unrelated male. Pairs were classified into two groups: "uncontested" dominance (UD) and "contested" dominance (CD), with 4 pairs each. Dominant females in UD pairs showed significantly higher frequencies (4.1) of agonism (piloerection, attack and chasing) than their subordinates (0.36), and agonistic behaviors were overall more frequently displayed by CD than by UD pairs. Subordinates in CD pairs exhibited more agonistic behavior (2.9) than subordinates in UD pairs (0.36), which displayed significantly more submissive (6.97) behaviors than their dominants (0.35). The data suggest that there is more than one kind of dominance relationship between female common marmosets. Assessment of progesterone levels showed that while subordinates in UD pairs appeared to be anovulatory, the degree of ovulatory disruption in subordinates of CD pairs was more varied and less complete. We suggest that such variation in female-female social dominance relationships and the associated variation in the degree and reliability of fertility suppression may explain variations of the reproductive condition of free-living groups of common marmosets.

Assuntos

RESUMO

Dominance status among female marmosets is reflected in agonistic behavior and ovarian function. Socially dominant females receive submissive behavior from subordinates, while exhibiting normal ovulatory function. Subordinate females, however, receive agonistic behavior from dominants, while exhibiting reduced or absent ovulatory function. Such disparity in female fertility is not absolute, and groups with two breeding females have been described. The data reported here were obtained from 8 female-female pairs of captive female marmosets, each housed with a single unrelated male. Pairs were classified into two groups: "uncontested" dominance (UD) and "contested" dominance (CD), with 4 pairs each. Dominant females in UD pairs showed significantly higher frequencies (4.1) of agonism (piloerection, attack and chasing) than their subordinates (0.36), and agonistic behaviors were overall more frequently displayed by CD than by UD pairs. Subordinates in CD pairs exhibited more agonistic behavior (2.9) than subordinates in UD pairs (0.36), which displayed significantly more submissive (6.97) behaviors than their dominants (0.35). The data suggest that there is more than one kind of dominance relationship between female common marmosets. Assessment of progesterone levels showed that while subordinates in UD pairs appeared to be anovulatory, the degree of ovulatory disruption in subordinates of CD pairs was more varied and less complete. We suggest that such variation in female-female social dominance relationships and the associated variation in the degree and reliability of fertility suppression may explain variations of the reproductive condition of free-living groups of common marmosets.

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RESUMO

The mating system of callitrichids has been reported to be monogamous, polygynous and polyandrous. In Callithrix jacchus, groups with 2 breeding females and groups with 1 breeding female have been reported. Our purpose was to evaluate the occurrence of occasional reproduction by subordinate females in free-ranging C. jacchus groups characterized as monogamous. Four groups were monitored at a field site of IBAMA-Brazil for between 20 and 72 months. We recorded the birth of 7 sets of twins to subordinate females that had never reproduced before. Sexual activities were recorded opportunistically: dominant females copulated with only the resident male, while subordinates copulated with extra-group males. We suggest these were essentially monogamous groups that occasionally had 2 reproductive females. Between-group copulations seem to be an alternative strategy used by the subordinates. Despite the costs, there would probably be benefits as a result of scanning for vacancies for reproductive positions in neighbouring groups and the establishment of ties with extra-group males that might become a reproductive partner in the future.

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Callithrix and Leontopithecus exhibit ecological differences that have implications for the patterns of infant care. In C. jacchus, which uses a small home range because it depends mainly on plant exudates, infants can forage independently early in their life. L. chrysomelas, which feeds mainly on fruits and insects, needs larger home ranges and, therefore, its infants have a more extensive period of dependence. Three families of C. jacchus and four families of L. chrysomelas were studied in captivity. The animals were observed starting from the birth of the infants up to their 8th week of age. Our results suggest that the pattern of infant transfer in L. chrysomelas did not follow the one reported for L. rosalia in that transfers from the mother occurred much earlier. L. chrysomelas infants were carried for about 15% of total time during the 8th week of life against less than 1% in C. jacchus in the same week. Infant care seems to be more extensive in L. chrysomelas than in C. jacchus, and the period of exclusive mother carrying in L. chrysomelas is shorter than that observed in L. rosalia.

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RESUMO

In callitrichids, and especially in the Callithrix and Saguinus genera, reproductive suppression maintains the breeding exclusivity of dominant females. It has been suggested that dominance may be inferred from agonistic behavior of females. The purpose of this study was to assess the adequacy of behaviors as indicators of hormonal status in Callithrix jacchus females. Two pairs of twin females were observed for affiliative, agonistic and sexual behaviors for 20 weeks, in four stages of increasingly potential competition for one male. During the same period, blood samples were taken regularly for progesterone determination by ELISA. The two pairs differed markedly as to behaviors and hormonal status: pair 1 showed a well established behavioral dominance and only one ovulating female from the beginning of the observation period; pair 2 showed competition for dominance until the last stage of observation, when one of the females started ovulating. Correlations between behaviors and progesterone levels showed differences between subordinate and dominant females mostly in pair 2. Although limited in number of animals studied, these results suggest that there is a relationship between behavior and hormones in female marmosets, but this relationship may be useful in the identification of the physiological status of females only in groups where the dominance is not well established.

Assuntos

RESUMO

In callitrichids, and especially in the Callithrix and Saguinus genera, reproductive suppression maintains the breeding exclusivity of dominant females. It has been suggested that dominance may be inferred from agonistic behavior of females. The purpose of this study was to assess the adequacy of behaviors as indicators of hormonal status in Callithrix jacchus females. Two paires of twin females were observed for affiliative, agonistic and sexual behaviors for 20 weeks, in four stages of increasingly potential competition for one male. During the same period, blood samples were taken regularly for progesterone determination by ELISA. The two pairs differed markedly as to behaviors and hormonal status: pair 1 showed a well established behavioral dominance and only one ovulating female from the beginning of the observation period; pair 2 showed competition for dominance until the last stage of observation, when one of the females started ovulating. Correlations between behaviors and progesterone levels showed differences between subordinate and dominant females mostly in pair 2. Although limited in number of animals studied, these results suggest that there is a relationship between behavior and hormones in female marmosets, but this relationship may be useful in the identification of the physiological status of females only in groups where the dominance is not well estblished

Assuntos