The number of people on Earth and human activities are currently taking on frightening proportions with far-reaching consequences for our planet, its biodiversity and ultimately the human race itself. Ten thousand years ago, humans represented 1% of the total biomass of all land vertebrates. The rest was made up by wild animals. Currently, humans, livestock and pets make up 99% of terrestrial vertebrate biomass, while wild animals represent only 1%. It took millennia for the human population to reach the 1 billion mark and that only by 1890. By 1960, however, the world population had grown to 3 billion. Today there are 8 billion people living on our planet. According to Population Matters, the world population will be approximately 10,4 billion by the end of this century, despite the gradual decline in the growth rate in some countries. There is only a 23% chance that the total population growth rate will tail off before 2100. The population of the 47 least developed countries is likely to triple between 2017 and 2100 to around 3 billion. There are currently 62 million people in South Africa. About 67,9% of our population (in 2021) live in urban areas. The South African population grew by 0,87% in 2023. The fertility rate is 2,30 (2023). It is estimated that by 2050 75,5 million people will be living in South Africa, with 8 out of every 10 people living in urban areas, which would significantly increase the pressure on infrastructure. The Global Footprint Network states that humans currently use the resources of 1,75 Earths. If the situation does not improve, by 2050 we would need the equivalent of three Earths to survive. More than 4 billion people will have little or no water by 2050, and South Africa even now has been classified as a "water-stressed" country. Medical science is continually contributing to more babies surviving their entry into the world and to our living increasingly longer. Life expectancy has risen from 46 years in 1950 to 73,2 years in 2023. By 2050 it will be 77 years. What can be done? Empowerment of women is important. Population growth can be curbed to a reasonable extent by giving more girls access to education. This certainly does not mean that girls or women alone should be held responsible for the current population growth, but much more will have to be done about sex education, women's rights will have to be actively promoted and there will have to be better provision and use of contraceptives. Obviously, these issues should be approached and handled with due caution. In this regard, countries such as Thailand and South Korea have, in the recent past, proved that good education may result in lower birth rates. In Africa, women with no education have an average of 5,4 children; women who completed high school an average of 2,7 children and women with tertiary education an average of 2.2. In Nigeria, every year of school attendance by girls cuts the birth rate by a tenth. In addition, intensified efforts to reform economies and societies should be considered. For the sake of the survival of the human species and the sustainability of the Earth, ecological and economic justice and the empowerment ofwomen have to be encouraged. The Millennium Project - a global participatory think tank that was founded in 1996 under the auspices of the American Council for the United Nations University, but which became independent in 2009 and has since grown into a global network of institutions and individuals - aims to improve humankind's prospects for a better future. It recommends, among other things, the following: • Support a policy aimed at improving the survival of children, responsible family planning and educational opportunities for (especially) girls. • Improve methods that will ensure skills and employment opportunities for young people, as well as care and services for the elderly. • Implement the UN's urban agenda. • Create enough smart cities where citizens with urban intelligence can help in eco-smart ways with the necessary improvements in the city. • Increase training in resilience, and improve disaster prediction and management. • Provide guidance for people about urban ecology. • Intensify research and development in saltwater agriculture (halophytes or salt plants) on coastlines to produce food for humans and animals, biofuel and pulp for the paper industry, and to absorb carbon dioxide (CO2). This will ease the pressure on freshwater agriculture. • Improve agricultural and irrigation management. • Invest in precision agriculture and aquaculture. • Reduce food losses from the "farm to the mouth" (one third or 1,3 billion tons of agricultural production is wasted in this way every year). • Establish seaweed to restore wild fish populations along coastlines. The World Bank estimates that 90% of marine life is completely depleted. • Expand the production of insects for animal feed and human diets (insects have a low environmental impact, and 2 billion people already supplement their diet with insects today). • Encourage vegetarianism. Although there are more ways to address these important global challenges, responsible family planning remains one of the most important. This is an extremely sensitive issue for many people (especially in Africa), but if it is not promoted in a humane, informed and responsible way, the sustainability of life on our planet will increasingly come under tremendous pressure in various respects.

Die aantal mense op aarde en hulle/ons aktiwiteite neem tans skrikwekkende afmetings aan met wydlopende gevolge vir ons planeet, biodiversiteit en uiteindelik onsself. Die moderne mens het sy teenwoordigheid op die aarde en die benutting van hulpbronne baie lank as sy onaantasbare reg gesien. Die huidige uitwerking van byvoorbeeld bevolkingsgroei en besoedeling versteur die aarde se natuurlike ritme in so 'n mate dat ons nou nie meer op 'n kitsoplossing kan hoop nie. Die mens se getalle neem teen so 'n tempo toe dat dit nie net nadelig vir die planeet is nie, maar ook vir die mensdom self. Wat kan gedoen word? Bemagtiging van vroue speel 'n belangrike rol. Dit beteken beslis nie dat meisies en vroue alleen vir die huidige bevolkingsgroei verantwoordelik gehou moet word nie. Die bevolkingsgroei kan egter in 'n redelike mate vertraag word deur veral meer meisies toegang tot onderwys en opleiding te gee - asook hul lewensomstandighede te verbeter. Ook sal daar heelwat meer aan seksopvoeding gedoen moet word, vroueregte sal daadwerklik bevorder moet word en daar sal beter voorsiening en gebruik van voorbehoedmiddels moet wees. Uiteraard moet hierdie kwessies met die nodige omsigtigheid benader en hanteer word. In hierdie verband kan onder andere Thailand en Suid-Korea genoem word wat in die onlangse verlede bewys het dat goeie onderwys geboortesyfers laat daal. In Afrika het vroue wat geen onderwys ontvang nie, gemiddeld 5,4 kinders; vroue wat hoërskool voltooi het gemiddeld 2,7 kinders en vroue wat tersiêre studie deurloop het, gemiddeld 2,2 kinders. In Nigerië sny elke jaar wat meisies skool bywoon, die geboortesyfer met 'n tiende. Hiermee saam sal daar ook verskerpte pogings moet wees om ekonomieë en samelewings te hervorm. Ter wille van die mens se voortbestaan en die volhoubaarheid van lewe op aarde moet ekologiese en ekonomiese geregtigheid, en die bemagtiging van vroue aangemoedig word.

ABSTRACT. The aimed of this study was to evaluate the influence of dietary protein levels on the biochemical and hematological parameters of pirarucu (Arapaima gigas). A total of 60 pirarucus specimens were used with an initial average weight of 499 ± 36 g and an initial average length of 40.30 ± 10.10 cm, stocked with densities of four pirarucus per fish tank network 48 m2 of water surface. Feed was provided three times a day (8 am, 1 and 6 pm), with five different levels of crude protein (CP) in diet: 34, 36; 38 and 40 and 45% CP. The fish were euthanized at 310 experimental days with an average of 8.0 ± 1.0 kg of body weight. Blood samples were collected by tail vessel venipuncture, divided into two aliquots 2 mL and used for determination of biochemical levels and blood count. The results were submitted to analysis of variance and regression for CP levels, with the results showed as averages followed by the standard deviation. Orthogonal contrasts were applied to verify linear and quadratic effects at 5% significance. It was observed that the parameters referring to the blood count, given by erythrocytes, hemoglobin, packed cell volume, MCV, HCM, CHCM, glucose and total proteins showed no differences between the different diets. The average values of total proteins were 3.80 ± 0.30 g L-1, glucose and triglycerides shown averages 43.45 ± 5.65 and 56.98 ± 5.80 mg dL-1, respectively. The maximum cholesterol level 120.00 ± 13.33 mg dL-1 was obtained at the 35.4% CP level in the growth phase. Protein levels in diet influenced the cholesterol levels in the pirarucu growth phase, however, they did not influence the other biochemical and hematological parameters. ABSTRACT Arapaima gigas. gigas . gigas) 49 3 4030 30 40.3 1010 10 10.1 cm 4 m surface 8 ( am pm, pm , pm) (CP 34 45 31 80 0 8. 1. venipuncture count deviation 5 significance erythrocytes hemoglobin volume MCV HCM CHCM diets 380 3.8 030 0.3 L1, L1 L 1, L-1 4345 43 43.4 565 65 5.6 5698 56 98 56.9 580 5.8 dL1, dL1 dL respectively 12000 120 00 120.0 1333 13 33 13.3 dL- 354 35 35.4 phase however 403 40. 101 10. 3. 03 0. L- 434 43. 5. 569 9 56. 58 1200 12 120. 133 13. 35.

Resumen Las rayas del género Potamotrygon son peces con forma dorsoventral aplanada. Son animales tranquilos, que solo atacan al ser agredidos o amenazados. Poseen en su cola estructuras punzantes, conocidas como espinas, envueltas por una vaina tegumentaria con tejidos secretores de componentes tóxicos. Suelen permanecer quietos en aguas superficiales, ocultos bajo arena o barro, lo que facilita su contacto accidental con humanos, con la probable generación de lesiones, al utilizar su cola hacia arriba y adelante en forma de látigo. Las lesiones son más frecuentes en hombres, en los meses estivales y en los miembros inferiores, seguidos por los miembros superiores. La lesión se asocia a dolor urente, casi inmediato y de gran intensidad, por el efecto traumático generado por las espinas, la persistencia de las mismas o sus fragmentos y por el efecto químico generado por sus toxinas. En ocasiones se asocia a la formación de necrosis y úlceras profundas o reacción granulomatosa por cuerpo extraño, con requerimientos de desbridamiento quirúrgico. Las lesiones fatales son infrecuentes y pueden resultar de una lesión torácica penetrante, laceraciones cervicales, compromiso de vía aérea, heridas vasculares o infecciones. Se deben realizar estudios de imágenes para evidenciar restos de la espina. La herida debe ser higienizada y se debe retirar la espina o sus fragmentos a la brevedad y sumergir el área lesionada en agua tan caliente como el paciente pueda tolerar, por 30 a 90 minutos, buscando disminuir el dolor y generar vasodilatación, junto con la analgesia y cobertura antibiótica y antitetánica. Se presentan tres casos de pacientes con lesiones por raya de río, dos de ellos por Potamotrygon brachyura, especie endémica del río de La Plata y el tercero por una raya no identificada. Se expone además una revisión bibliográfica a fin de remarcar la importancia de su diagnóstico temprano y su correcto abordaje.

Abstract The rays of the Potamotrygon genus are fish with a dorsoventrally flattened shape. They are calm animals that only attack when are provoked or threatened. They have sharp structures in their tail, known as spines, wrapped by a tegumentary sheath with tissues that secrete toxic components. They typically remain still in shallow waters, concealed under sand or mud, which increases accidental human contact. This contact can lead to injuries, as they whip their tail upwards and forwards. Injuries are more common in males during summer months, often affecting lower limbs followed by upper limbs. Injuries are characterized by immediate intense burning pain due to trauma from the spine or its fragments and chemical effects from its toxins. Occasionally, injuries lead to necrosis, deep ulcers, or foreign body granulomatous reactions requiring surgical debridement. Fatal injuries are rare but can result from thoracic penetration, cervical lacerations, airway compromise, vascular wounds, or infections. Imaging studies are necessary to detect spine remnants. Wounds should be cleaned, and spines or fragments removed promptly. The affected area should be immersed in water, as hot as tolerable for 30 to 90 minutes to reduce pain, induce vasodilation, and must supplemented with analgesia, antibiotic coverage, and tetanus prophylaxis. Three cases of river stingray injuries are presented, two from Potamotrygon brachyura, an endemic species of the Rio de la Plata river, and one from an unidentified ray. Additionally, a literature review emphasizes the importance of early diagnosis and proper management.

ABSTRACT. The study aimed to determine the fatty acid profile, omegas and lipid quality indeces in commercial cuts of pirarucu (Arapaima gigas) of the slaughter class 11.1 to 14.0 kg. Sample collections were carried out in two fish processing industries located in Rondônia state, Brazil. The experimental design was completely randomized, with processing performed in triplicate. Data were submitted to ANOVA to assess differences between commercial cuts in chemical compositions. If ANOVA appeared statistically significant (α=0.05), the averages were compared by Tukey's test. In the composition of fatty acids, there was a difference (p <0.05) between cuts. Commercial cuts that expressed the highest percentages of SFAs tail fillet 51.2%, of MUFAs fillet mignon 39.8% and of PUFAs deboned cut 20.7%. The indeces prescribed for lipid quality, ∑PUFAs/∑SFAs, ∑PUFAs (n-6/∑n-3), AI, TI and HH, indicate that commercial cuts have lipid quality. Deboned is the cut with the highest PUFA fatty acid content, with the highest values of Omega 3, 6, 7 and n-9 being also expressed. Nutritional information is important for the processes of conservation and processing, development of new products on the market, as well as guiding the form of preparation, thus providing commercial security for different market niches. ABSTRACT profile Arapaima gigas 111 11 1 11. 140 14 0 14. kg state Brazil randomized triplicate compositions α=0.05, α005 α α=0.05 , 05 (α=0.05) Tukeys Tukey s test acids p <0.05 005 512 51 2 51.2% 398 39 8 39.8 207 20 20.7% PUFAsSFAs ∑PUFAs/∑SFAs n6/∑n3, n6n3 nn n 6/∑n 3 6 (n-6/∑n-3) AI HH content n9 9 n- preparation niches α00 α=0.0 (α=0.05 <0.0 00 5 51.2 39. 20.7 n6 n3 n6/∑n3 n6n 6n (n-6/∑n-3 α0 α=0. (α=0.0 <0. 51. 20. n6/∑n (n-6/∑n- α=0 (α=0. <0 (n-6/∑n α= (α=0 < (α= (α

Resumo Esta pesquisa se concentra nas características hematológicas, na morfologia eritrocitária e em alguns parâmetros bioquímicos do tambor vermelho Sciaenops ocellatus (Perciformes: Sciaenidae), cultivado em ambiente aquático natural em áreas próximas à foz do rio (L1), em estuários (L2) na província de Ha Tinh e em áreas costeiras (L3) na cidade de Nha Trang, província de Khanh Hoa do Vietnã. Um total de 18 espécimes foi examinado na pesquisa, seis em cada local. O sangue foi coletado da veia da cauda, usando um microscópio para pesquisar a morfologia e medidores automatizados para determinar os parâmetros bioquímicos do sangue. A análise das amostras de sangue mostrou que a taxa de distúrbios morfológicos dos eritrócitos do tambor vermelho em todos os três locais era bastante alta. Os dois principais tipos de distúrbios eram deformidade nuclear e distribuição de matéria nuclear. Mudanças no tamanho, na forma e no núcleo dos eritrócitos foram relacionadas à concentração de sal nos locais de cultivo. O conteúdo de hemoglobina no sangue era estável em todas as três regiões. Outros parâmetros hematológicos, como número de eritrócitos, parâmetros bioquímicos sanguíneos (glicose, SGOT, SGPT, ureia, creatina, ferro plasmático, albumina e proteína), apresentam diferenças entre os locais, o que evidencia diferentes reações de uma mesma espécie em diferentes ambientes e condições.

Abstract This research focuses on hematological characteristics, erythrocyte morphology and some biochemical parameters of red drum Sciaenops ocellatus (Perciformes: Sciaenidae), cultured in natural water environment in areas near river mouth (L1), estuaries (L2) in Ha Tinh province and coastal areas (L3) in Nha Trang city, Khanh Hoa province of Vietnam. A total of 18 speciments were examined in research, six in each location. Blood was drawn from the tail vein, using a microscope to research morphology and automated gauges to determine blood biochemical parameters. Analysis of blood samples showed that the rate of red drum’s erythrocyte morphology disorders in all three locations was quite high. The two main types of disorders were nuclear deformity and nuclear-matter distribution. Changes in erythrocyte size, shape and nuclear were related to salt concentration at culture locations. Blood hemoglobin content was stable in all three regions. Other hematological parameters such as the number of erythrocytes, blood biochemical parameters (glucose, SGOT, SGPT, urea, creatine, plasma iron, albumin, and protein) have differences among the locations, which showed the different reactions of the same species with different environmental conditions.

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Abstract Knowledge of the environmental and transport fate of pesticides is integral to characterizing environmental exposures. Agencies such as the Environmental Protection Agency (EPA) 27 integrate the characterization of an exposure with ecological effects to determine the risks of pesticide use. The three most widely used herbicides in Colombia are glyphosate, propanil, and glufosinate ammonium. Although glyphosate had, since the early 1970’s, been considered an environmentally friendly herbicide, the weight of the evidence of studies beginning in the 1990s show that inadvertent applications in wetlands can be fatal to the larvae of amphibians. Although glyphosate formulations are typically considered moderately toxic (LC50 = 1-10 ppm) for most aquatic organisms, for many amphibian species they are highly toxic (LC50 ˂ 1 ppm). This concern is compounded by the fact that Colombia has an incredibly high diversity of amphibians (746 species). In addition, chronic exposures of some amphibian species to sublethal concentrations, which are more likely found in the environment, have been shown to cause decreased survival, intersex gonads, tail damage, prolongation of time to metamorphosis, and liver lipidosis. In Colombia, aerial applications of Glyphos-Cosmo-Flux have been used since 1997 to fumigate illicit coca crops. As of 2019, the International Union for Conservation of Nature (IUCN) Red List had 285 species of amphibians in Colombia considered threatened. We found that 132 of the endangered (EN) and critically endangered (CR) amphibian species were present in 11 of the 32 Colombian departments with illegal coca plantations. Therefore, studies are needed to evaluate the impact of the coca eradication program on the amphibian population of the country. Propanil is the main herbicide used in rice fields. Despite its rapid environmental degradation ((1 day in aerobic conditions), studies on the impact of propanil have found that at projected application rates (4.5 kg/ha), within 48 hours after application, it reduces dissolved oxygen to levels critically important for survival of fish. At very low concentrations of 50 ppb or less of propanil, this effect correlates with lower phytoplankton production rather than higher community respiration. Despite being mild to moderately toxic at acute exposures, chronic exposure data also show that concentrations greater than 9 ppb affect the growth, reproduction, and development of fish and invertebrates. With respect to glufosinate ammonium, although it is highly likely to contaminate surface (runoff) and groundwater due to its physicochemical properties, data suggest that it is practically non-toxic to aquatic and terrestrial species. The acute hazard ratios were well below the level of concern, and therefore the EPA determined that the acute risk to non-target terrestrial and aquatic organisms is very low.

Resumo O conhecimento do destino ambiental e de transporte dos pesticidas é parte integrante da caracterização das exposições ambientais. Agências como a Agência de Proteção Ambiental (EPA) 27 integram a caracterização de uma exposição com efeitos ecológicos para determinar os riscos do uso de pesticidas. Os três herbicidas mais usados na Colômbia são glifosato, propanil e glufosinato de amônio. Embora o glifosato tenha sido considerado um herbicida ambientalmente correto desde o início da década de 1970, foi evidenciado por estudos iniciados na década de 1990 que aplicações inadvertidas em pântanos podem ser fatais para larvas de anfíbios. Embora as formulações de glifosato sejam tipicamente consideradas moderadamente tóxicas (CL50 = 1-10 ppm) para a maioria dos organismos aquáticos, para muitas espécies de anfíbios elas são altamente tóxicas (CL50 ˂ 1 ppm). Essa preocupação é agravada pelo fato de que a Colômbia tem uma diversidade incrivelmente alta de anfíbios (791 espécies). Além disso, foi demonstrado que exposições crônicas de algumas espécies de anfíbios a concentrações subletais, que são mais prováveis no ambiente, causam diminuição da sobrevivência, gônadas intersex, dano na cauda, prolongamento do tempo até a metamorfose e lipidose hepática. Na Colômbia, aplicações aéreas de Glyphos-Cosmo-Flux têm sido usadas desde 1997 para fumigar plantações ilícitas de coca. Em 2019, a Lista Vermelha da União Internacional para a Conservação da Natureza (IUCN) tinha 285 espécies de anfíbios na Colômbia consideradas ameaçadas. Descobrimos que 132 das espécies de anfíbios em perigo (EN) e criticamente em perigo (CR) estavam presentes em 11 dos 32 departamentos colombianos onde há mais plantações ilegais de coca. Portanto, são necessários estudos para avaliar o impacto do programa de erradicação da coca na população de anfíbios do país. O propanil é o principal herbicida usado nos campos de arroz. Apesar de sua rápida degradação ambiental ((1 dia em condições aeróbicas), estudos sobre o impacto do propanil descobriram que nas taxas de aplicação projetadas (4,5 kg / ha), ele reduz o oxigênio dissolvido a níveis criticamente importantes para a sobrevivência dos peixes em 48 horas. após a aplicação. Este efeito se correlaciona com a produção de fitoplâncton mais baixa, em vez de maior respiração da comunidade em concentrações muito baixas de 50 ppb ou menos de propanil. Apesar de ser leve a moderadamente tóxico em exposições agudas, os dados de exposição crônica também mostram que concentrações maiores que 9 ppb afetam o crescimento, a reprodução e o desenvolvimento de peixes e invertebrados. Com relação ao glufosinato de amônio, embora tenha grande probabilidade de contaminar a superfície (escoamento) e as águas subterrâneas devido às suas propriedades físico-químicas, os dados sugerem que é praticamente atóxico para as espécies aquáticas e terrestres. As razões de risco agudo estavam bem abaixo do nível de preocupação e, portanto, a EPA determinou que o risco agudo para organismos terrestres e aquáticos não visados é muito baixo.

Resumo Henneguya sacacaensis n. sp. é descrito em espécimes do Osteichthyes Satanoperca jurupari (Heckel, 1840), coletados na área de Proteção Ambiental do rio Curiaú na cidade de Macapá no estado do Amapá, Brasil. Com auxílio de microscopia óptica e análises moleculares, esses parasitos foram analisados e observados nas brânquias em forma de cistos, contendo centenas de esporos e apresentaram a prevalência de 57,14%. Os cistos encontrados nas lamelas branquiais tinham formatos ovais e esbranquiçados. Seus esporos apresentaram um comprimento médio de 46,5 (41,3-56,92) µm, corpo fusiforme medindo 16,5 (13,16-20,01) µm de comprimento e 5,1 (3,91-6,12) µm de largura, suas duas cápsulas polares apresentam uma conicidade de 3,83 (3,4-4,32) µm e sua largura 1,68 µm (1,4-1,99), a cauda 30 (22,47-41,67) µm de comprimento, contento um filamento polar de 7 à 9 voltas. Análises morfológicas e filogenéticas permitiram a preposição de uma nova espécie, Henneguya sacacaensis n. sp, que pertence à família Myxobolidae e ao gênero Henneguya.

Abstract This study describes Henneguya sacacaensis n. sp. in specimens of the Osteichthyes Satanoperca jurupari (Heckel, 1840), collected in the Rio Curiaú Environmental Protection Area in the city of Macapá, state of Amapá Brazil. Using optical microscopy and molecular analysis, these cyst-shaped parasites were analyzed. The gills of 57.14% of the analyzed S. jurupari contained hundreds of spores. The cysts found on the gill lamellae were oval-shaped and whitish. The Henneguya spores had an average length of 46.5 (41.3-56.92) µm. The fusiform body of the Henneguya measured 16.5 (13.16-20.01) µm long and 5.1 (3.91-6.12) µm in width, the two polar capsules had a taper of 3.83 (3.4-4.32) µm and a width of 1.68 (1.4-1.99) µm, and the tail measured 30 (22.47-41.67) µm in length, containing a polar filament coiled seven to nine times. Morphogical and phylogenetic analysis allowed the preposition of a new species, Henneguya sacacaensis n. sp, that belongs to the family Myxobolidae and the genus Henneguya.

Abstract This study aimed to describe the occurrence, morphology and prevalence of Spirocamallanus krameri, a parasite of Hoplerythrinus unitaeniatus collected in state of Pará, Brazil. The morphological and morphometric characteristics are consistent with the species S. krameri, by having a hexagonal mouth opening, 16 cephalic papillae and two lateral papillae on the amphids. The buccal capsule is internally different in both sexes, with (11–13) spiral ridges in males and (13–17) spiral ridges in females. The basal ring is well developed, and three teeth are present in males and absent in females. Ten sessile caudal papillae and a pair of phasmidial pores occur in males. The spicules are small, subequal, 81–101 µm in length and the tail is tapered. The vulva in females is postequatorial, the tail is conical with lateral phasmidial pores. Among the species of Spirocamallanus that have short spicules, the general morphology of S. krameri most resembles that of S. inopinatus, but differs from that species, which have two cephalic teeth visible (absent in S. krameri) and specimens of S. inopinatus do not have sexual dimorphism in the buccal capsule of present in S. krameri.

Abstract Introduction: Current research of fish locomotion is focused on creating better underwater vehicles and how environmental stress factors modify swimming. Objective: To study the relation of morphometric characteristics with burst swimming in six representative species of continental fishes from Costa Rica. Methods: We measured total length, standard length, height and area of the tail of 38 individuals from six species. We used a Kruskall-Wallis test and a Boxplot graphic to compare species; and a PCA test to identify body variables that influence swimming. A Non-Metric Dimensional Scaling (NMDS) test was done for species and position in the water column. Results: The fastest swimming corresponded to A. nigrofasciata (9,29cm/s), while S. salvini (1,65cm/s) was the slowest. Burst swimming speed is influenced by body size and tail type, and differed with position in the water column, being surface species the fastest. Conclusions: Morphological and ecological characteristics determine differences in burst swim.

Resumen “Morfometría y nado explosivo es seis especies de peces continentales de Costa Rica”. Introducción: La investigación actual sobre del nado de los peces se centra en crear vehículos autónomos submarinos y cómo factores ambientales de estrés modifican la natación. Objetivo: Estudiar la relación de las características morfométricas con el nado explosivo para seis especies representativas de peces continentales de Costa Rica. Metodología: Medimos la longitud total, la longitud estándar, la altura y el área de la cola de 38 individuos de seis especies. Usamos la prueba de Kruskall-Wallis y un gráfico de diagrama de cajas para comparar las especies; , y un análisis de componentes principales (PCA) para identificar las variables corporales que influyen en el nado. Una prueba de escalamiento no dimensional métrico (NMDS) para mostrar la relación entre las especies y la posición ecológica en la columna de agua. Resultados: El nado más rápido se encontró en A. nigrofasciata (9,29cm/s), mientras que S. salvini (1,65cm/s) fue la especie más lenta del estudio. La velocidad de la ráfaga de natación está influenciada por el tamaño del cuerpo y el tipo de cola, y difiere por la posición en la columna de agua, siendo las especies en la superficie las más rápidas. Conclusiones: Las características morfológicas como las ecológicas determinarán las diferencias en la velocidad de nado explosivo.

RESUMEN Eremophilus mutisii, pez catalogado en estado como vulnerable, que por su importancia sociocultural y ecológica genera retos investigativos, uno de ellos, conocer sus características histológicas del desarrollo embrionario, desde la fecundación hasta la eclosión. Para ello, se obtuvieron embriones de individuos adultos y maduros sexualmente, capturados en la represa del Sisga, ubicada en el municipio de Chocontá, Cundinamarca, inducidos sexualmente con extracto pituitario de carpa. Los ovocitos y el semen fueron obtenidos por presión abdominal 24 horas después de la última dosis, a 14±1°C. La toma de muestras, se realizó cada 60 minutos, durante las primeras doce horas post-fertilización (HPF); a partir de aquí y hasta la eclosión, las muestras fueron fijadas en formol Bufferado al 4%, cada 6 horas y sometidas a rutina de histología. Los resultados mostraron que los óvulos fertilizados presentaron forma esférica, color verde claro y diámetro promedio de 1270µm. El primer clivaje, se observó a las 2HPF; la blastulación inició a las 9HPF; los movimientos epibólicos y la gastrulación, se observaron desde la 12HPF hasta la 30HPF, con el cierre del blastoporo. A las 60HPF, se evidenció el desprendimiento de la cola del saco vitelino y a las 66HPF, se dio inicio a los primeros movimientos autónomos. Finalmente, a las 72HPF inició la eclosión, mostrando las larvas ausencia de pigmentación y evidenciándose un tracto digestivo rudimentario, sin abertura bucal y anal. Se observó la presencia de abundante saco vitelino, con movimientos verticales continuos de la larva.

ABSTRACT Eremophilus mutisii, due to its vulnerable condition and its potential for fish farming, generates research challenges; one of them is to know the embryonic changes of the E. mutisii based on morphological and histological features from fertilization to hatching. The embryos were obtained from adult and sexually mature individuals of the Capitán de la Sabana (Eremophilus mutisii), sexually induced with carp pituitary extract. Oocytes and semen were obtained by abdominal pressure 24 hours after the last dose at 14±1°C. Sampling was performed every 60 minutes for the first twelve hours´ post-fertilization (HPF); from here on at hatching, the samples were fixed every 6 hours. The embryos were fixed in 4% formalin for observing the morphological features and for the histological studies. Results revealed that the fertilized eggs had spherical shape, light green color and average diameter of 1270µm. The first cleavage at 2 HPF was observed, the blastulation began at 9 HPF. Epibolic movements and gastrulation were observed from 12 HPF to 30 HPF with blastopore closure. At 60 HPF the yolk sac tail detachment was evident and at 66 HPF the first autonomous movements began. Finally, at 72 HPF, the hatching began, showing absence of pigmentation and evidencing a rudimentary digestive tract without oral and anal opening. It was observed the presence of abundant yolk sac with continuous vertical movements of the larva.

Resumen El Concepto de Discontinuidad Serial afirma que la formación de embalses en cadena dentro de los ríos genera cambios en la estructura de la biota acuática que se acumulan a lo largo del cauce. En el río Porce (Cuenca del río Magdalena-Cauca, Colombia) se formaron dos embalses en cadena, los embalses Porce II y Porce III. Para conocer la respuesta del ensamblaje de peces dentro del sector del río que fue embalsado se tomaron muestras de cuatro periodos de lluvias abundantes y cuatro de menores lluvias entre los años 2011 y 2013, en sitios dentro de los dos embalses seleccionados según su posición en el eje longitudinal (cola, transición y presa); para eliminar el efecto de la profundidad en cada sitio se tomaron muestras a dos profundidades (superficial-fondo). Se capturaron 15 especies; 12 en Porce II y 10 en Porce III. Se observaron diferencias espaciales en cuanto a la composición y estructura de especies de peces, tanto en el eje longitudinal (cola-presa), como en el vertical (superficie-fondo). En el embalse Porce II, la riqueza y la abundancia de individuos disminuyeron en dirección cola-presa y fue mayor en la superficie que en el fondo; en el embalse Porce III, aunque la riqueza presentó la misma tendencia en el eje longitudinal, la abundancia fue mayor en el fondo que en la superficie. Las características del ensamblaje no estuvieron asociadas a los periodos pluviométricos en ninguno de los dos embalses. Se concluye que la composición y estructura del ensamblaje está definida por las características morfológicas del embalse, así como la edad y tiempo de retención hidráulica.

Abstract The Serial Discontinuity Concept affirms that the formation of reservoirs in cascade within rivers generates changes in the structure of the aquatic biota that accumulate along the basin. In the Porce River (Magdalena-Cauca River Basin, Colombia) two reservoirs were formed in cascade, Porce II and Porce III. To know the response of the fish assemblage in the sector of the river that was dammed, we collected samples during four periods of abundant rains and four of lesser rains from 2011 to 2013 from sites inside both reservoirs selected according to position on the longitudinal axis (tail, transition and dam). To eliminate the effect of depth, at every site, we took samples from two depths, surface and bottom. 15 species were captured; 12 in Porce II and 10 in Porce III. Differences in the composition and structure of the species of fish were found to vary depending on the location along the river flow (from tail to dam), and also by the water depth (surface to river bottom). In Porce II reservoir, the richness and the abundance of fish diminished in direction tail to dam and the abundance decreased from surface to bottom. In Porce III though the species richness presented the same trend along the longitudinal axis, the abundance was greater on the bottom that at the surface. The characteristics of the assemblage were not associated with the rainfall periods in either reservoir. One concludes that the composition and structure of the assemblage are defined by the morphologic characteristics of the reservoir, as well as the age and time of hydraulic retention.

Abstract Two Amazonian closely related tetras – cardinal Paracheirodon axelrodi and green neon P. simulans – were artificially acclimatized to environmental chambers mimicking future climate change scenarios (mild, moderate and extreme), using a microcosm facility. P. simulans survived (100%) to all scenarios after 30 days exposure, while P. axelrodi presented decreasing survival percentages according to environmental severity. These differences may be the reflection of distinct natural acclimatization to microhabitats between the species, which differ in thermal conditions. Survival responses might be related to differences in relative gene expression of lactate dehydrogenase (Ldh), suggesting that P. axelrodi anaerobic potential is lower or non-existent compared to P. simulans, not tolerating long-term thermal challenges. Accordingly, increases in temperature and in CO2 levels caused increases in energy demand and resulted in activation of the anaerobic pathway, as demonstrated by the higher enzyme levels measured in head and tail portions of both species. Sustained anaerobic glycolysis is possible when fish live in challenging environments (low oxygen or high temperature). Our results clearly show that P. simulans has a larger scope for survival to higher energy demands due to its increased anaerobic potential compared to P. axelrodi.

ABSTRACT In this work we evaluated the essential amino acid profile of muscle Crocodylus acutus and calculated their chemical score of main proteins used in their diet in captivity. The separation and identification of amino acids was carried out by high performance liquid chromatography coupled to a fluorescence detector. The calculation of chemical score was obtained by dividing the value of each essential amino acid between the same amino acid of the reference protein. The lowest value of the relationships is the chemical score. The amino acids present in greater quantities in the tail muscle are glutamic acid, lysine and leucine (16.96, 9.84 and 8.87 g amino acid per 100 g of protein, respectively), whereas histidine, methionine and tryptophan (2.99, 2.93 and 0.59 g amino acid per 100 g of protein) were the lowest. The chemical score obtained results showed that the proteins of animal origin, preferably marine fish and supplemented with terrestrial animals ingredients, including beef liver appear to be the most effective. The incorporation of plant proteins in diets for C. acutus does not appear as a viable alternative due to deficiencies in several essential amino acids such as methionine, lysine and threonine.

RESUMO: O objetivo deste trabalho foi avaliar as alterações na microbiota do trato intestinal, parâmetros hematológicos e índices zootécnicos de lambaris-do-rabo-amarelo (Astyanax bimaculatus) alimentados com diferentes frequências de oferta do probiótico (Lactobacillus spp.). Os lambaris (1.200) foram distribuídos em doze caixas, divididos em três tratamentos, oferta de 100%, 25% e 0% (controle) de alimentações suplementadas com probiótico. Após 87 dias, os peixes alimentados com dieta suplementada, independente da frequência (100% e 25%), apresentaram aumento na contagem total de bactérias ácido láticas 7,99±0,15log UFC mL-¹ e -7,04±1,29log UFC mL-¹, respectivamente, no trato intestinal e redução de Pseudomonas spp. tanto em 100% quanto em 25% (4,09 ± 0,84 log UFC mL-¹ e 4,00±1,12 log UFC mL-¹, respectivamente) em relação ao tratamento controle (6,74±1,04log UFC mL-¹). Os peixes alimentados com 100% das dietas suplementadas com probiótico apresentaram maior contagem de leucócitos (47,7±6,7x103µL-1), linfócitos (36,0±2,6x103µL-1), monócitos (12,0±4,2x103µL-1), assim como maior peso médio final (10,60±0,89g) e taxa de crescimento semanal (0,80±0,08g.semana-1) que os demais tratamentos (25% de oferta de probiótico e controle). O probiótico (Lactobacillus spp.) oferecido em 25% de alimentos (ou mais) altera a microbiota de lambari de rabo amarelo (A. bimaculatus), no entanto, deve ser oferecido em 100% de alimentos para melhorar o perfil hematologia e desempenho produtivo.

ABSTRACT: The aim of this research was to evaluate the changes in intestinal tract microbiota, hematological parameters and zootechnical indexes of yellowtail lambaris (Astyanax bimaculatus) fed with different probiotic supply frequencies (Lactobacillus spp.). Lambaris (1,200) were distributed in twelve boxes, divided in three treatments, 100% supply; 25% and 0% (control) of feeds supplemented with probiotic. After 87 days, fish fed with supplemented diet, regardless of frequency (100% and 25%), showed an increase in the total lactic acid bacteria count of 7.99±0.15 log CFU mL-1 and 7.04±1, 29 log UFC mL-¹ respectively, in the intestinal tract and decrease of Pseudomonas spp. in both 100% and 25% (4.09±0.84log UFC mL-1 and 4.00±1.12log UFC mL-1, respectively) in relation to the control treatment (6.74±1.04log UFC mL-1). Fish fed with 100% of diets supplemented with probiotics had a higher leukocyte count (47.7±6.7x103μL-1), lymphocytes (36.0±2.6x103μL1), monocytes (12.0±4.2x103μl-1), as well as higher mean final weight (10.60±0.89g) and weekly growth rate (0.80±0.08g.week-1) than the other treatments (25% of probiotic offered and control). Probiotic (Lactobacillus spp.) offered in 25% of feeds (or more) alters the yellowtail lambari microbiota (A. bimaculatus); however, must be offer in 100% of feeds to improve the hematology profile and productive performance.

Abstract Identifying potential patterns in pirarucu (Arapaima gigas) composition, as a function of the different fish muscle zones (dorse, venter, ventrecha and tail), was the main objective of this research. For such, the different pirarucu muscle zones were evaluated, in order to obtain proximate composition and minerals content. It was also determined amino acids and fatty acids contents in fish muscle. The dorsal, ventral and tail muscle zones presented similar moisture (76.5-78.2%), protein (17.8-18.9%), total lipids (1.0-1.5%) and ash (0.9-1.2%) contents. On the other hand, the ventrecha zone presented 25.8% of protein and the major total lipids content (17.1%). The main minerals found in fish muscle were K (183.5-288.6 mg/100 g muscle) and Na (65.1-175.5 mg/100 g). Glutamic acid (3027.6 mg/100 g muscle) was the main amino acid found in fish muscle, which presented 48% of essential amino acids in the protein fraction. Lipids content showed 57.3% of unsaturated fatty acids and 42.7% of saturated fatty acids.