Estrutura populacional, táticas reprodutivas e alocação de energia em peixes de igarapé da Reserva Ducke, Amazônia Central brasileira

The reproductive cycle of freshwater tropical fish respond to changes in flood pulse, but little is known about the reproductive patterns of fish species in streams that undergo drastic changes depending on local rainfall. This study considered life strategy and patterns of energy allocation in six small fish species from small streams of Reserva Adolpho Ducke, Central Amazonia. Samplings were carried out monthly from January to December/2013, using small seine nets, dip nets and small gill nets. Size structure, length-weight relationship, sex ratio, gonadossomatic index, cavity fat index, body condition, breeding season and its relation to rainfall levels and caloric density in muscle were considered for each species, which were associated with life-histoty strategies of each species. The results showed that Rivulus micropus, Pyrrhulina cf. brevis and Hyphessobrycon aff. melazonatus fit into opportunistic strategy but the viii first two uses energy from the muscle to the development of the gonads and the third one uses energy from other sources; Aequidens pallidus and Crenuchus spilurus are prone to equilibrium strategy and do not use energy from muscle to gonad maturation; Bryconops giacopinii is a seasonal species that does not use muscle energy for gonadal development. Our results indicate that some tactics hypothetically associated with different reproductive strategies may not necessarily be fixed and interdependent, but rather, can be combined in different ways in response to the characteristics and dynamics of the environment where they live.O ciclo reprodutivo dos peixes de água doce tropicais responde às variações no pulso de inundação, mas pouco se sabe sobre os padrões reprodutivos das espécies de peixes de igarapés, que sofrem mudanças drásticas em função das chuvas locais. O presente estudo considerou a estratégia de vida e os padrões de alocação de energia em seis espécies de pequeno porte oriundas de igarapés de terra firme da Reserva Adolpho Ducke, Amazônia Central. As amostras foram obtidas mensalmente, de janeiro a dezembro de 2013, utilizando redinhas, puçás e malhadeiras pequenas. Para cada espécie foram analisados: estrutura em comprimento, relações comprimento padrão-peso total, proporção sexual, índice gonadossomático, índice de gordura cavitária, fator de condição, época reprodutiva e sua relação com os níveis de precipitação e densidade calórica em músculo; os mesmos foram associados às estratégias reprodutivas de cada espécie. Os resultados mostraram que Rivulus micropus, Pyrrhulina cf. brevis e Hyphessobrycon melazonatus são espécies oportunistas sendo que as duas primeiras utilizam energia proveniente do músculo para o desenvolvimento das gônadas e a terceira utiliza energia de outras fontes; Aequidens pallidus e Crenuchus spilurus são espécies com tendência à estratégia equilíbrio e não utilizam energia proveniente do músculo para a maturação gonadal; e Bryconops giacopinii é uma espécie com tendência sazonal que não utiliza energia do músculo para o desenvolvimento gonadal. Nossos resultados indicam que algumas táticas hipoteticamente associadas aos diferentes tipos de estratégias reprodutivas não constituem respostas fixas e necessariamente interdependentes, mas, ao contrário, podem ser combinadas de diferentes formas em resposta às características e dinâmica do meio onde vivem

Pterygoplichthys pardalis (Castelnau, 1855), an introduced species in the Cauca River Basin, Colombia.

Reportamos la introducción de Pterygoplichthys pardalis- una especie íctica de agua dulce de la cuenca del río Amazonas- en la cuenca del río Cauca y en las represas de Salvajina y Calima, Colombia. Alcance: Registramos y evaluamos taxonómicamente a P. pardalis para verificar su identificación, evitando que se eliminen especies nativas morfológicamente similares. Metodología empleada: Se examinó material depositado en algunas colecciones de ictiología, evaluando 35 caracteres morfométricos para su identificación siguiendo las claves de Armbruster. Estos resultados se compararon con la literatura disponible para el género Pterygoplichthys. Conclusiones: Este artículo reporta algunos errores en identificación, principalmente de Pterygoplichthys undecimalis, que en realidad corresponden a ejemplares de P. pardalis. También sugiere dos posibles mecanismos que explican su introducción en cuencas nacionales: i) descuidos durante el comercio de especies ornamentales de peces y por parte de sus compradores y ii) proyectos de acuicultura que pretenden “mejorar” la economía regional sin considerar las características e idoneidad de las especies que buscan fomentar. Finalmente, este artículo alerta sobre la introducción de P. pardalis en cuencas nacionales, y sus posibles efectos sobre especies y ecosistemas nativos.We report Pterygoplichthys pardalis introduction - a freshwater fish species from the Amazon river basin - in the Cauca river basin and in Salvajina and Calima dams, Colombia. Scope: We registered and taxonomically evaluated P. pardalis to verify its identification, seeking to avoid the elimination of native morphologically similar species. Methodology: Material deposited in some ichthyology collections was examined, evaluating 35 morphometric characters for identification following Armbruster’s keys. These results were compared with the available literature for Pterygoplichthys genus. Conclusions: This article reports some identification errors, mainly regarding Pterygoplichthys undecimalis, which actually correspond to P. pardalis. We also suggest two possible mechanisms that explain P. pardalis introduction into national basins: i) oversights during ornamental fish species trade and by their buyers, and ii) aquaculture projects that, seeking to “improve” regional economy, not take into consideration characteristics and suitability of the species they seek to promote. Finally, this article alerts about P. pardalis introduction in national basins and their possible effects on native species and ecosystems

Hydropower effects on Prochilodus magdalenae (Prochilodontidae) reproduction: evidence from endocrine response

Objective. Describe the endocrine response associated with the reproduction of a tropical potamodromous fish under changes in the flow discharge produced by hydropower in an Andean. Materials and methods. We analyzed Prochilodus magdalenae reproduction in individuals from two sectors of a Neotropical river basin: one with a natural flow and another one with a regulated hydrological regime. Results. In the sector of the basin with the natural flow we found that the production of hormones related with fish reproduction (FSH and LH) was correlated with the gonadosomatic index, while in fish experiencing hydropeaking due to hydroelectric operation no such correlation was detected. Conclusions. Hormone production associated to reproduction of the Potamodromous fish was sensitive to changes in water level and discharge. Then, fish exposed to hydropeaking would be receiving ambiguous stimuli that affect hormone production, reproduction synchronization with environmental cues, and ripening, which are essential for reproductive succes

Recovering care networks through food sovereignty: A case study in Wayúu Communities, Colombia

This thesis analyses the importance of care in a humanitarian crisis context in La Guajira (Colombia) which disproportionately affects the Wayúu indigenous community and explores how this community recovers its care networks. I start from the premise that the humanitarian crisis faced by the Wayúus is a care crisis. I argue that it is critical to identify the causes for the loss of care networks and practices and the crisis responses from this community and humanitarian assistance institutions. For this, I use three academic fields: the ethics of care, (feminist) political ecology and food sovereignty. I take the quotidian and the Wayúu food systems and food sovereignty as the place for analysing care networks and practice transformations, arguing that food and the body are the first dimensions to reflect environmental and socio-political changes. This research results from ethnographic work in Wayúu communities in three cities of La Guajira. I explore care transformations (loss and recovery) guided by the Wayúu experiences and stories, tracing how the community's food systems have been shaped in response to territorial and social shifts and identifying the sources of these changes. I do this exploration through three empirical chapters. In the first one, I discuss La Guajira's large-scale extractivism activities' impact on Wayúu's care network transformation. A second chapter focuses on the crisis, discussing the role of humanitarian institutions, their crisis management approach, and how it leads to bad care policies. In the last empirical chapter, I focus on the Wayúu community's response to the crisis, emphasising that the community has not remained immobile. Instead, they deploy a series of practices and actions that celebrate and position care at the centre of decisions and systems. Interestingly, and what constitutes the main contribution of this thesis, the Wayúu communities are using food sovereignty arguments and practices to recover care networks, showing how care and food sovereignty are co-created and co-dependent and highlighting the every day as a place where transformative proposals and actions can emerge in a powerful way

Data Prochilodus.xlsx

Data for <i>Prochilodus magdaleanea</i>, a potamodromous fish from Colombia rivers.<div>Collected between June 2010 and June 2011</div><div>Includes:</div><div>Lenght</div><div>Weight</div><div>Sex</div><div>Maturity stage</div><div>Gonadal weight</div><div>Liver weigth</div><div>Number of LSH cells</div><div>Number of FSH cells</div

Efectos de la generación de energía hidroeléctrica en la reproducción de Prochilodus magdalenae (Prochilodontidae): evidencia de la respuesta endócrina

ABSTRACT Objective. Describe the endocrine response associated with the reproduction of a tropical potamodromous fish under changes in the flow discharge produced by hydropower in an Andean. Materials and methods. We analyzed Prochilodus magdalenae reproduction in individuals from two sectors of a Neotropical river basin: one with a natural flow and another one with a regulated hydrological regime. Results. In the sector of the basin with the natural flow we found that the production of hormones related with fish reproduction (FSH and LH) was correlated with the gonadosomatic index, while in fish experiencing hydropeaking due to hydroelectric operation no such correlation was detected. Conclusions. Hormone production associated to reproduction of the Potamodromous fish was sensitive to changes in water level and discharge. Then, fish exposed to hydropeaking would be receiving ambiguous stimuli that affect hormone production, reproduction synchronization with environmental cues, and ripening, which are essential for reproductive success.RESUMEN Objetivo. Describir la respuesta endocrina asociada con la reproducción de un pez potamódromo tropical ante cambios en el régimen de descarga de caudal producido por la generación de hidro-energía en un río Andino. Materiales y métodos. Se analizó la reproducción de Prochilodus magdalenae en individuos de dos sectores de una cuenca neotropical: uno con flujo hidrológico natural y otro con un régimen regulado. Resultados. En la sección de la cuenca con flujo natural, se encontró que la producción de hormonas relacionadas con la reproducción de peces (FSH y LH) estaba correlacionada con el índice gonadosomático, mientras que en peces bajo la influencia del pulso de agua producto de la operación hidroeléctrica esta correlación no fue detectada. Conclusiones. La producción de hormonas asociadas con la reproducción en peces potamódromos fue sensible a cambios en el nivel/caudal. En consecuencia, peces expuestos a las alteraciones en el pulso de caudal estarían recibiendo estímulos ambiguos que afectan la producción de hormonas, la sincronización de la reproducción con las señales ambientales y la maduración, lo cual es esencial para el éxito reproductivo

Reproductive allocation by Amazon fishes in relation to feeding strategy and hydrology

Seasonal environments favor the evolution of capital breeding, whereby reproduction uses surplus energy from resources acquired during an earlier period. Consequently, reproductive effort in capital breeders is expected to depend on traits associated with energy storage rather than environmental conditions at the time of reproduction. Based on a 15-year dataset, we investigate the effect of phenotype (body size and condition) and environmental conditions (intensity of hydrological seasons, predator density, and density of conspecifics) on fecundity three capital breeding fish species from the strongly seasonal Amazon River floodplain: Psectrogaster rutiloides, Triportheus angulatus, and Acestrorhynchus falcirostris. Fecundity of all three species was strongly correlated with phenotype and modulated by unfavorable environmental conditions during the period of reproduction, especially high density of conspecifics. Fecundity was negatively affected by the density of conspecifics for small females of A. falcirostris, and for T. angulatus females with poor body condition. Fecundity of P. rutiloides declined during periods of drought when density of conspecifics was highest. A clear tradeoff between quantity and quality of oocytes was found only for P. rutiloides. This study highlights that reproductive allocation of capital breeders in seasonal environments is strongly linked to environmental conditions before and during the reproductive period