ESTADO DE ARTE DE LA BIOLOGÍA Y CULTIVO DE PEJELAGARTO (Atractosteus tropicus)

Native fresh water fish are an important source of food and protein for human society. A full study of the native aquatic species and the development of technologies that allow the controlled production of these fish in a profitable, innocuous and environment-friendly manner, are some of the big challenges for aquaculture in this millennium. Therefore, the state of the art of the biology and breeding of tropical gar (Atractosteus tropicus) is presented in this study, thus stimulating the construction of sustainable tropical aquaculture of native fresh water species. The study consisted of an exhaustive revision of databases from peer-reviewed publications, grey publications and national and international technical reports by organizations committed to this species, its reproduction and local consumption. Likewise, a model of technological innovation to systematize the knowledge generated regarding its breeding is proposed, which allows determining the current state of advancement of this theme, and to discover new opportunities for research to fill knowledge gaps.Los peces de agua dulce nativos son una fuente importante de alimento y proteína para la sociedad humana. Un estudio completo de las especies acuícolas nativas y el desarrollo de tecnologías que permitan de manera controlada una producción de estos peces de manera rentable, inocua y amigable con el ambiente son algunos de los grandes retos para la acuicultura en este milenio. Por esta razón, en este trabajo se presenta el estado de arte de la biología y cultivo del pejelagarto (Atractosteus tropicus), estimulando así la construcción de una acuicultura tropical sustentable de especies nativas de agua dulce. El estudio consistió en una revisión exhaustiva de bases de datos de publicaciones arbitradas, publicaciones grises, e informes técnicos nacionales e internacionales de organizaciones comprometidas con esa especie, su reproducción, engorda y consumo local. Así mismo se propone un modelo de innovación tecnológica para sistematizar el conocimiento generado sobre su cultivo, lo cual permite determinar el estado actual de avances en el tema y descubrir nuevas oportunidades de investigación para cubrir vacíos de conocimiento

Development of digestive enzymes in larvae of Mayancichlid Cichlasoma urophthalmus

The development of digestive enzymes during the early ontogeny of the Mayan cichlid (Cichlasoma urophthalmus) was studied using biochemical and electrophoretic techniques. From yolk absorption (6 days after hatching: dah), larvae were fed Artemia nauplii until 15 dah, afterward they were fed with commercial microparticulated trout food (45% protein and 16% lipids) from 16 to 60 dah. Several samples were collected including yolk-sac larvae (considered as day 1 after hatching) and specimens up to 60 dah. Most digestive enzymes were present from yolk absorption (5–6 dah), except for the specific acid proteases activity (pepsin-like), which increase rapidly from 8 dah up to 20 dah. Three alkaline proteases isoforms (24.0, 24.8, 84.5 kDa) were detected at 8 dah using SDS–PAGE zymogram, corresponding to trypsin, chymotrypsin and probably leucine aminopeptidase enzymes, and only one isoform was detected (relative electromobility, Rf = 0.54) for acid proteases (pepsin-like) from 3 dah onwards using PAGE zymogram. We concluded that C. urophthamus is a precocious fish with a great capacity to digest all kinds of food items, including artificial diets provided from 13 dah

Advances In Conservation and Management of the Alligator Gar: A Synthesis of Current Knowledge and Introduction to a Special Section

Growing appreciation of biodiversity and the role of apex predators, along with increasing popularity of multispecies and trophy‐oriented angling, has elevated the status of gars – in particular, the Alligator Gar Atractosteus spatula – among anglers and biologists alike. As a result, considerable effort has been spent in recent years to gain a working knowledge of the biology and ecology of the species in order to advance science‐based management. In January 2019, the Southern Division of the American Fisheries Society Alligator Gar Technical Committee hosted a symposium entitled, Advances in the conservation and management of North American gars to showcase the results of research and management efforts conducted throughout the species’ range. Fishery researchers and managers presented a diversity of works, furthering our understanding of population dynamics, stock assessment, genetics, hatchery practices and stocking, habitat use, and angler desires associated with Alligator Gar fisheries. In this introduction to our special section, we introduce these works and provide a synthesis of the current state of scientific knowledge regarding the Alligator Gar. We hope that this will provide context to the works presented in the symposium, and serve to guide the development of future research that addresses remaining knowledge gaps concerning the species and its growing fishery

Sex-specific differences in transcriptome profiles of brain and muscle tissue of the tropical gar

Abstract Background The tropical gar (Atractosteus tropicus) is the southernmost species of the seven extant species of gar fishes in the world. In Mexico and Central America, the species is an important food source due to its nutritional quality and low price. Despite its regional importance and increasing concerns about overexploitation and habitat degradation, basic genetic information on the tropical gar is lacking. Determining genetic information on the tropical gar is important for the sustainable management of wild populations, implementation of best practices in aquaculture settings, evolutionary studies of ancient lineages, and an understanding of sex-specific gene expression. In this study, the transcriptome of the tropical gar was sequenced and assembled de novo using tissues from three males and three females using Illumina sequencing technology. Sex-specific and highly differentially expressed transcripts in brain and muscle tissues between adult males and females were subsequently identified. Results The transcriptome was assembled de novo resulting in 80,611 transcripts with a contig N50 of 3,355 base pairs and over 168 kilobases in total length. Male muscle, brain, and gonad as well as female muscle and brain were included in the assembly. The assembled transcriptome was annotated to identify the putative function of expressed transcripts using Trinotate and SwissProt, a database of well-annotated proteins. The brain and muscle datasets were then aligned to the assembled transcriptome to identify transcripts that were differentially expressed between males and females. The contrast between male and female brain identified 109 transcripts from 106 genes that were significantly differentially expressed. In the muscle comparison, 82 transcripts from 80 genes were identified with evidence for significant differential expression. Almost all genes identified as differentially expressed were sex-specific. The differentially expressed transcripts were enriched for genes involved in cellular functioning, signaling, immune response, and tissue-specific functions. Conclusions This study identified differentially expressed transcripts between male and female gar in muscle and brain tissue. The majority of differentially expressed transcripts had sex-specific expression. Expanding on these findings to other developmental stages, populations, and species may lead to the identification of genetic factors contributing to the skewed sex ratio seen in the tropical gar and of sex-specific differences in expression in other species. Finally, the transcriptome assembly will open future research avenues on tropical gar development, cell function, environmental resistance, and evolution in the context of other early vertebrates