Diversity, distribution and relative abundance of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan / Diversidade, distribuição e abundância relativa da fauna de mosquitos (Diptera: Culicidae) de Malakand e Dir Lower, Paquistão

Abstract The present study was conducted to evaluate the diversity, distribution (C) and relative abundance (RA) of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan. Collection of specimens (n = 1087) was made during September 2018 to July 2019 at six different habitats including freshwater bodies, rice fields, animal sheds, indoors, drains and sewage waters. Specimens were collected through light traps, pyrethrum spray, aspirators and nets and subsequently killed, preserved and then arranged in entomological boxes for identification. Three genera were identified namely Culex, Anopheles and Aedes. A total of fourteen species were identified namely: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762) An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) and An. annularis (van der Wulp, 1884). Cx. quinquefasciatus was found constantly distributed in the study area with RA = 16.5% and C = 100%. An. annularis was found as a satellite species, sporadically distributed in the study area having RA = 0.9% and C = 17%. Diversity indices of mosquitoes in the studied habitats were found as, Shannon-Wiener Index (2.415), Simpson Index (9.919), Fisher's Index (2.269) and Margalef's Index (1.859). A statistically significant difference was recorded in mosquito diversity in the six habitats (Kruskal-Wallis, chi-squared, H = 17.5, df = 5, P = 0.003 at α = 0.05). The present study encompasses mosquito fauna of Malakand, Pakistan with respect to diversity, relative abundance and distribution in diverse habitats and all seasons of the year. This will assist scientists working in various fields related with epidemiology, medical and veterinary entomology, ecology and allied areas of biological sciences.

Resumo O presente estudo foi conduzido para avaliar a diversidade, distribuição (C) e abundância relativa (RA) da fauna de mosquitos (Diptera: Culicidae) de Malakand e Dir Lower, Paquistão. A coleta de espécimes (n = 1087) foi feita durante o período de setembro de 2018 a julho de 2019 em seis habitats diferentes, incluindo corpos d'água, campos de arroz, galpões de animais, ambientes internos, ralos e águas residuais. Os espécimes foram coletados por meio de armadilhas luminosas, spray de piretro, aspiradores e redes e posteriormente mortos, preservados e depois dispostos em caixas entomológicas para identificação. Três gêneros foram identificados, nomeadamente Culex, Anopheles e Aedes. Um total de 14 espécies foi identificado, a saber: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762), An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) e An. annularis (Van der Wulp, 1884). Cx. quinquefasciatus foi encontrado constantemente distribuído na área de estudo com AR = 16,5% e C = 100%. A. annularis foi encontrada como espécie satélite, distribuída esporadicamente na área de estudo com RA = 0,9% e C = 17%. Os índices de diversidade de mosquitos nos habitats estudados foram encontrados como índice de Shannon-Wiener (2,415), índice de Simpson (9,919), índice de Fisher (2,269) e índice de Margalef (1,859). Uma diferença estatisticamente significativa foi registrada na diversidade de mosquitos nos seis habitats (Kruskal-Wallis, qui-quadrado, H = 17,5, df = 5, P = 0,003 em α = 0,05). O presente estudo abrange a fauna de mosquitos de Malakand, Paquistão, com respeito à diversidade, abundância relativa e distribuição em diversos habitats e em todas as estações do ano. Isso ajudará os cientistas que trabalham em vários campos relacionados com a epidemiologia, entomologia médica e veterinária, ecologia e áreas afins das ciências biológicas.

Relationship between fish assemblage structure and predictors related to estuarine productivity in shallow habitats of a Neotropical estuary

The variability of fish assemblage structure with respect to seasonality in salinity and productivity remains to be elucidate to many Neotropical estuaries. In this study, we hypothesized that salinity gradient and a set of variables related to ecosystem productivity drive community parameters in the shallow-water fish assemblage of the north-south axis of the Paranaguá Estuarine Complex (Southern Brazilian coast). Samples were taken with beach seine monthly from May 2000 to April 2001. Supporting our hypothesis, richness and abundance increased with turbidity, warmer waters of the rainier summer seasons, which are more productive. This environmental setting favors reproduction, as well as juvenile recruitment and growth, whose intensities are highest in this period. Highest abundance was found in inner areas, which may be explained by greater food and habitat availability. Richness was higher in more saline waters, due to the proximity of the rich pool of marine fish species. We suggest that local human interventions (e.g., dredging) should be avoided during the rainy seasons that are critical for species life cycles. Salinization, low estuarine productivity, and warmer waters, which are expected with climate change and human impacts in the local watershed, could affect the integrity of the local fish assemblage.

A variabilidade da estrutura de assembleia de peixes em relação à sazonalidade da salinidade e produtividade ainda não foi elucidada para muitos estuários Neotropicais. Neste estudo, testamos a hipótese de que um conjunto de variáveis relacionadas à produtividade e ao gradiente de salinidade estuarino determina a estrutura da ictiofauna de habitats rasos do eixo norte-sul do Complexo Estuarino de Paranaguá (litoral sul brasileiro). As amostras foram obtidas mensalmente com "picaré", entre maio de 2000 e abril de 2001. Corroborando com a hipótese, riqueza e abundância aumentaram em águas mais turvas e quentes nas estações chuvosas e produtivas de verão, favorecendo reprodução, bem como recrutamento e crescimento juvenil que são mais intensos neste período. Abundância foi maior nas zonas internas, devido à maior oferta de alimento e habitat. Riqueza foi maior em águas mais salinas, devido à proximidade da ictiofauna marinha, que é mais rica. Sugerimos que intervenções humanas locais (como dragagem) sejam evitadas nas estações chuvosas que são críticas para o ciclo de vida das espécies. Salinização, redução da produtividade estuarina e águas mais quentes, esperadas com a mudança climática global e impactos humanos na bacia hidrográfica local, poderão afetar a integridade da ictiofauna local.

Salinity study of irrigation waters used in rice fields / Estudo da salinidade em águas de irrigação utilizadas na lavoura arrozeira

In Santa Catarina State, Brazil, rice is predominantly cultivated in irrigated systems, and irrigation water is generally collected directly from watercourses. Irrigated rice crops, which are sensitive to water salinity, form the basis of the economy of the Mampituba River Basin region, southern Brazil. This study aimed to assess salinity fluctuations in waters collected from the Mampituba River for irrigation of rice crops during the four seasons of the year. For salinity determination, water samples were collected from six sites along the river course, from the source to the mouth. Three subsamples were collected at each site, with a mean interval of 15 days between collections, beginning in May 2016 and ending in April 2017. Samples were evaluated for electrical conductivity (EC). Assessment of salinity damage was performed in seedlings of rice cultivars 'IRGA 417' and 'EPAGRI 106'. When seedlings reachedthe S2 stage, they were transplanted into flooded soil at different saline concentrations. EC values ranged from 224 to 20,120 µS cm−1over the experimental period, being higher at sites closer to the sea. The highest salinity values were recorded betweenNovember 2016 and January2017. It was possible to observe an inverse relationship between rainfall and water salinity. Salinity causes damage to rice plants, particularly seedlings. Symptoms include leaf tip chlorosis, leaf curling, and necrosis of old leaves. It is important forrice farmers to understand salt wedge fluctuations within their estuary as well as variations in salinity levels at different sites and times of the year.(AU)

No estado de Santa Catarina predomina na sua totalidade o cultivo de arroz irrigado e a água utilizada para a irrigação destas lavouras em sua maioria são retiradas diretamente de cursos de água. A região da Bacia Hidrográfica do Rio Mampituba tem sua economia baseada no cultivo do arroz irrigado, cujas plantas são sensíveis à salinidade. O presente trabalho objetivou determinar a flutuação de salinidade na água do Rio Mampituba (Sul do Brasil) utilizada para irrigação na lavoura arrozeira durante as quatro estações do ano. Para a determinação da salinidade foram realizadas coletas de água em seis locais no percurso do rio, desde sua nascente até a foz. Em cada local foram coletadas três subamostras de água com intervalo médio de 15 dias iniciado em maio de 2016 e finalizado em abril de 2017 e analisada a condutividade elétrica (CE). A caracterização do dano por salinidade em plântulas de arroz foi realizada nas cultivares IRGA 417 e EPAGRI 106. As plântulas foram transplantadas para solo inundado com diferentes concentrações salinas no estádio S2. A CE ao longo do período avaliado variou de 224 a 20.120 µS cm−1e foi maior nos pontos mais próximos ao mar. Os maiores valores de salinidade foram observados entre os meses de novembro de 2016 e janeirode 2017. Foi possível observar relação inversa entre a precipitação e a salinidade. A salinidade causa danos as plantas de arroz sendo os principais danos observados em plântulas. Estes danos foram clorose da ponta do limbo foliar, enrolamento foliar e necrose de folhas velhas. É importante que os orizicultores saibam como é a flutuação da cunha salina dentro do estuário, além de quais níveis incidem em cada local e em cada época do ano.(AU)

Distribution and abundance of dinoflagellates from the coastal waters of Karachi, Pakistan, northern part of the Arabian Sea / Distribuição e abundância de dinoflagelados nas águas costeiras de Karachi, Paquistão, parte norte do Mar da Arábia

The present study reports on seasonal and spatial variations in diversity, distribution and abundance of dinoflegellates and indicates the presence of HAB species in Pakistan waters. A total of 179 taxa, recorded in this study from offshore and near-shore waters, belong to 41 genera in 26 families and 10 orders. The high species count (149 species) was recorded from Manora Island offshore station (MI-1) and 105 spp, 109 spp and 115 spp were encountered from the Mubarak village offshore station (MV-1), Manora near shore station (MI-2) and Mubarak Village near-shore station (MV-2) respectively. Tripos furca was the dominant and frequently occurring species (> 1 x10³ to > 25 x10³ cells L-¹ from coastal and >1x 105 cells L-¹ from near-shore stations) in addition to less abundant Alexandrium catenella, Alexandrium sp., Alexandrium minutum, and Prorocentrum micans (>103 to 25x 10³cells/L). Another 44 species occurred in relatively low numbers (<10³ cell L-¹). Seventy species were found throughout the study period at all four stations. High number of species in three genera (Tripos (38), Protoperidinium (34) and Prorocentrum (20) was recorded. Potently toxic (16 genera 43 species) and HAB related (19 genera and 30 species) dinoflagellate taxa were also recorded. The percent contribution of dinoflagellates in total phytoplankton population generally remained below 20% except for a few instances. Manora Island stations had comparatively higher Shannon index and equitability and slightly lower dominance index. The PCA plot showed strong positive correlation among chlorophyll-a concentration, dissolved oxygen, total number of phytoplankton and dinoflagellates.

O presente estudo relata variações sazonais e espaciais na diversidade, na distribuição e na abundância de dinoflegelados e indica a presença de espécies de HAB nas águas do Paquistão. Um total de 179 táxons, registrados nesse estudo de águas offshore e próximas à costa, pertence a 41 gêneros em 26 famílias e 10 ordens. A alta contagem de espécies (149 espécies) foi registrada na estação offshore da Ilha de Manora (MI-1) e 105 spp., 109 spp. e 115 spp. foram encontrados na estação offshore da vila de Mubarak (MV-1), Manora perto da estação costeira (MI- 2) e estação próxima à costa da Vila de Mubarak (MV-2), respectivamente. Tripos furca foi a espécie dominante e de ocorrência frequente (> 1 x103 a > 25 x103 células L-1 da costa e > 1x 105 células Ll de estações próximas à costa), além de Alexandrium catenella menos abundante, Alexandrium sp., Alexandrium minutum e Prorocentrum micans (> 103 a 25x 103 células/L). Outras 44 espécies ocorreram em números relativamente baixos (< 103 células L-1). Setenta espécies foram encontradas durante o período de estudo em todas as quatro estações. Foi registrado um alto número de espécies em três gêneros (Tripos (38), Protoperidinium (34) e Prorocentrum (20). Potencialmente tóxicos (16 gêneros e 43 espécies) e HAB relacionados (19 gêneros e 30 espécies), táxons de dinoflagelados também foram registrados. A contribuição percentual de dinoflagelados na população fitoplanctônica total geralmente permaneceu abaixo de 20%, exceto em alguns casos. As estações da Ilha de Manora tinham índice de Shannon comparativamente mais alto e equitabilidade e índice de dominância ligeiramente mais baixos. O gráfico de PCA mostrou forte correlação positiva entre concentração de clorofila-a e oxigênio dissolvido, número total de fitoplânctons e dinoflagelados.

Distribution and abundance of dinoflagellates from the coastal waters of Karachi, Pakistan, northern part of the Arabian Sea / Distribuição e abundância de dinoflagelados nas águas costeiras de Karachi, Paquistão, parte norte do Mar da Arábia

The present study reports on seasonal and spatial variations in diversity, distribution and abundance of dinoflegellates and indicates the presence of HAB species in Pakistan waters. A total of 179 taxa, recorded in this study from offshore and near-shore waters, belong to 41 genera in 26 families and 10 orders. The high species count (149 species) was recorded from Manora Island offshore station (MI-1) and 105 spp, 109 spp and 115 spp were encountered from the Mubarak village offshore station (MV-1), Manora near shore station (MI-2) and Mubarak Village near-shore station (MV-2) respectively. Tripos furca was the dominant and frequently occurring species (> 1 x10³ to > 25 x10³ cells L-¹ from coastal and >1x 105 cells L-¹ from near-shore stations) in addition to less abundant Alexandrium catenella, Alexandrium sp., Alexandrium minutum, and Prorocentrum micans (>103 to 25x 10³cells/L). Another 44 species occurred in relatively low numbers (<10³ cell L-¹). Seventy species were found throughout the study period at all four stations. High number of species in three genera (Tripos (38), Protoperidinium (34) and Prorocentrum (20) was recorded. Potently toxic (16 genera 43 species) and HAB related (19 genera and 30 species) dinoflagellate taxa were also recorded. The percent contribution of dinoflagellates in total phytoplankton population generally remained below 20% except for a few instances. Manora Island stations had comparatively higher Shannon index and equitability and slightly lower dominance index. The PCA plot showed strong positive correlation among chlorophyll-a concentration, dissolved oxygen, total number of phytoplankton and dinoflagellates.(AU)

O presente estudo relata variações sazonais e espaciais na diversidade, na distribuição e na abundância de dinoflegelados e indica a presença de espécies de HAB nas águas do Paquistão. Um total de 179 táxons, registrados nesse estudo de águas offshore e próximas à costa, pertence a 41 gêneros em 26 famílias e 10 ordens. A alta contagem de espécies (149 espécies) foi registrada na estação offshore da Ilha de Manora (MI-1) e 105 spp., 109 spp. e 115 spp. foram encontrados na estação offshore da vila de Mubarak (MV-1), Manora perto da estação costeira (MI- 2) e estação próxima à costa da Vila de Mubarak (MV-2), respectivamente. Tripos furca foi a espécie dominante e de ocorrência frequente (> 1 x103 a > 25 x103 células L-1 da costa e > 1x 105 células Ll de estações próximas à costa), além de Alexandrium catenella menos abundante, Alexandrium sp., Alexandrium minutum e Prorocentrum micans (> 103 a 25x 103 células/L). Outras 44 espécies ocorreram em números relativamente baixos (< 103 células L-1). Setenta espécies foram encontradas durante o período de estudo em todas as quatro estações. Foi registrado um alto número de espécies em três gêneros (Tripos (38), Protoperidinium (34) e Prorocentrum (20). Potencialmente tóxicos (16 gêneros e 43 espécies) e HAB relacionados (19 gêneros e 30 espécies), táxons de dinoflagelados também foram registrados. A contribuição percentual de dinoflagelados na população fitoplanctônica total geralmente permaneceu abaixo de 20%, exceto em alguns casos. As estações da Ilha de Manora tinham índice de Shannon comparativamente mais alto e equitabilidade e índice de dominância ligeiramente mais baixos. O gráfico de PCA mostrou forte correlação positiva entre concentração de clorofila-a e oxigênio dissolvido, número total de fitoplânctons e dinoflagelados.(AU)

Deep-sea dragonfishes (Teleostei: Stomiiformes) collected from off northeastern Brazil, with a review of the species reported from the Brazilian Exclusive Economic Zone

The Stomiiformes includes about 455 species of mostly mesopelagic fishes in the families Diplophidae, Gonostomatidae, Phosichthyidae, Sternoptychidae, and Stomiidae. Here we report 55 species of the order collected during the ABRACOS (Acoustics along the BRAzilian COaSt) expeditions off northeastern Brazil, including islands and seamounts of Fernando de Noronha Ridge. Triplophos hemingi (Diplophidae), Pachystomias microdon and Melanostomias biseriatus (Stomiidae) are recorded for the first time in the western South Atlantic. Eustomias bibulbosus, Grammatostomias ovatus and Photonectes achirus (Stomiidae) are recorded for the first time in the South Atlantic. Eustomias minimus (Stomiidae), previously known from four poorly preserved specimens, is reported for the first time in the Atlantic. Occurrences of 18 species are confirmed or recorded for the first time in the Brazilian Exclusive Economic Zone: Triplophos hemingi (Diplophidae), Gonostoma denudatum (Gonostomatidae), Aristostomias grimaldii, Astronesthes gudrunae, Bathophilus nigerrimus, Borostomias elucens, Eustomias bibulbosus, E. braueri, E. minimus, E. schmidti, Grammatostomias ovatus, G. dentatus, Leptostomias gladiator, Melanostomias biseriatus, M. bartonbeani, Pachystomias microdon, Photonectes achirus, and Photostomias goodyeari (Stomiidae). Diagnostic and distributional data for all species recorded are provided, with new anatomical information presented for Melanostomias bartonbeani and Grammatostomias ovatus. A checklist of the 108 species of Stomiiformes confirmed in Brazilian waters is also presented.(AU)

Stomiiformes inclui cerca de 455 espécies válidas de peixes principalmente mesopelágicos, distribuídos nas famílias Diplophidae, Gonostomatidae, Phosichthyidae, Sternoptychidae e Stomiidae. Aqui, relatamos a ocorrência de 55 espécies de Stomiiformes coletadas durante as expedições ABRACOS (Acoustics along the BRAzilian COaSt) no nordeste do Brasil, incluindo as ilhas e montes submarinos da Cadeia de Fernando de Noronha. Triplophos hemingi (Diplophidae), Pachystomias microdon e Melanostomias biseriatus (Stomiidae) são registradas pela primeira vez no Atlântico Sul ocidental. Eustomias bibulbosus, Grammatostomias ovatus e Photonectes achirus (Stomiidae) são registradas pela primeira vez no Atlântico Sul. Eustomias minimus (Stomiidae), anteriormente conhecida a partir de quatro espécimes mal preservados, é reportada pela primeira vez no Atlântico. A ocorrência de 18 espécies é confirmada ou registrada pela primeira vez na Zona Econômica Exclusiva brasileira: Triplophos hemingi (Diplophidae), Gonostoma denudatum (Gonostomatidae), Aristostomias grimaldii, Astronesthes gudrunae, Bathophilus nigerrimus, Borostomias elucens, Eustomias bibulbosus, E. braueri, E. minimus, E. schmidti, Grammatostomias ovatus, G. dentatus, Leptostomias gladiator, Melanostomias biseriatus, M. bartonbeani, Pachystomias microdon, Photonectes achirus, e Photostomias goodyeari (Stomiidae). Dados diagnósticos e de distribuição de todas as espécies registradas são fornecidos, com novas informações anatômicas para Melanostomias bartonbeani e Grammatostomias ovatus. Uma lista preliminar das 108 espécies de Stomiiformes confirmadas em águas brasileiras também é apresentada.(AU)

Rocky reef fish biodiversity and conservation in a Brazilian Hope Spot region

Coastal islands of Grande Rio, located south Rio de Janeiro and Maricá cities have been under multiple anthropogenic impacts. Despite these problems, these insular systems shelter a high diversity of fish species. Reef fishes are essential components of tropical marine coastal communities, also providing food and income for millions of people around the world. In this work, we generated an updated checklist from Cagarras Islands Natural Monument and surrounding areas based on fisheries data, literature records and multiple sampling techniques, including the Submersible Rotating Video technique, used for the first time in Brazil. We present an inventory of 282 fish species representing 91 different families, with 21 new records for the study area, including a non-native species (Heniochus acuminatus). In addition, our results show a moderate endemism level for the Brazilian province (approximately 6.0%), while 10.5% of species are assigned to one of IUCN's threatened categories. Our efforts show the fish biodiversity scenario and their distribution on coastal islands more than 10 years after the Cagarras Islands Natural Monument establishment, reinforcing the importance of monitoring research programs for the management of this Marine Protected Area and surrounding waters, that play a key role for artisanal fisheries.

As ilhas costeiras do Grande Rio, ao sul das cidades do Rio de Janeiro e Maricá, têm sofrido múltiplos impactos antrópicos. Apesar destes problemas, esses sistemas insulares abrigam uma grande diversidade de espécies de peixes. Os peixes recifais são componentes essenciais das comunidades costeiras marinhas tropicais, fornecendo alimento e fonte de renda para milhões de pessoas em todo o mundo. Neste trabalho, geramos uma lista de verificação atualizada do Monumento Natural das Ilhas Cagarras e áreas do entorno com base em dados de pesca, registros da literatura e múltiplas técnicas de amostragem, incluindo a técnica de vídeo rotacional subaquático usada pela primeira vez no Brasil. Apresentamos um inventário de 282 espécies de peixes representando 91 famílias, com 21 novos registros para área de estudo, incluindo uma espécie não nativa (Heniochus acuminatus). Além disso, nossos resultados mostram um nível de endemismo moderado da província brasileira (aproximadamente 6,0%), sendo 10,5% das espécies classificadas em uma das categorias ameaçadas da IUCN. Nossos esforços mostram o cenário da biodiversidade de peixes e sua distribuição nas ilhas costeiras mais de 10 anos após o estabelecimento do Monumento Natural das Ilhas Cagarras, reforçando a importância de programas de pesquisa de monitoramento para a gestão desta Área Marinha Protegida e suas águas adjacentes, que desempenham papel fundamental para a pesca artesanal.

DNA barcoding of a tropical anguillid eel, Anguilla bicolor (Actinopterygii: Anguilliformes), in Indo-Pacific region and notes on its population structure

ABSTRACT The tropical anguillid eel, Anguilla bicolor McCelland, 1844, includes two subspecies, Anguilla bicolor bicolor McCelland, 1844 and Anguilla bicolor pacifica Schmidt, 1928, and is distributed across the Indo-Pacific region. Although A. bicolor is widely distributed and recognized as an important fish resource in the Indo-Pacific region, few studies have been conducted on its genetic variation and population structure. DNA barcoding of A. bicolor specimens collected in the Indo-Pacific region was carried out in this study using mitochondrial cytochrome c oxidase subunit I. Anguilla bicolor was found to diverge genetically, which supported its classification into two different subspecies. In addition, our study showed that A. bicolor bicolor had two genetically distinct populations/groups, and these different populations co-occur geographically in Indonesia and Malaysia in the eastern Indian Ocean. Our findings suggest that the eel larvae might be transported from at least two geographically different spawning grounds in the Indian Ocean, and then recruited to and settled in the same habitats in Indonesian and Malaysian waters. The molecular evidence calls for further research on the life history, stock assessment and protection of the populations of A. bicolor bicolor in Indonesia and Malaysia.

Supplemental irrigation using brackish water on maize in tropical semi-arid regions of Brazil: yield and economic analysis

Supplemental irrigation during dry spells could reduce maize yield losses in tropical semi-arid regions, notably in small farms. However, good quality water reserves are not sufficient to meet the demands of farming communities. Consequently, our objective was to evaluate the productivity and profitability of maize under different simulated rainfall scenarios, with and without supplemental irrigation (SI) with brackish water. The field experiments were carried out during the cropping seasons of 2018 and 2019 on Ultisol. The experiment followed a randomized block design in the split-plot scheme with four replicates. The plots were formed by simulating the water supply in the soil corresponding to four water scenarios (rainy, normal, drought and severe drought), and the sub-plots with or without SI with brackish water (Electrical conductivity of 4.5 dS m−1). Mean yields of green maize ears were 13,083, 11,532, 10,358 and 9,609 kg ha−1 for rainy, normal, drought and severe drought scenarios, as supplemented with brackish water. For the same treatments without SI the values were 11,394, 7,896, 3,913 and 1,374 kg ha−1, respectively. Data on farmer's income showed that under normal, drought and severe drought supplementation with brackish water becomes economically advantageous from 0.9, 1.0 and 2.4 ha, respectively, while maize cultivation without SI is not advantageous under the last two scenarios. For severe drought conditions, however, SI using brackish water reduced commercial yield by 27 % with negative effects on the farmers’ profitability. In this case, it is necessary to use water with either lower salinity or select salt tolerant crops.

Supplemental irrigation using brackish water on maize in tropical semi-arid regions of Brazil: yield and economic analysis

Supplemental irrigation during dry spells could reduce maize yield losses in tropical semi-arid regions, notably in small farms. However, good quality water reserves are not sufficient to meet the demands of farming communities. Consequently, our objective was to evaluate the productivity and profitability of maize under different simulated rainfall scenarios, with and without supplemental irrigation (SI) with brackish water. The field experiments were carried out during the cropping seasons of 2018 and 2019 on Ultisol. The experiment followed a randomized block design in the split-plot scheme with four replicates. The plots were formed by simulating the water supply in the soil corresponding to four water scenarios (rainy, normal, drought and severe drought), and the sub-plots with or without SI with brackish water (Electrical conductivity of 4.5 dS m−1). Mean yields of green maize ears were 13,083, 11,532, 10,358 and 9,609 kg ha−1 for rainy, normal, drought and severe drought scenarios, as supplemented with brackish water. For the same treatments without SI the values were 11,394, 7,896, 3,913 and 1,374 kg ha−1, respectively. Data on farmer's income showed that under normal, drought and severe drought supplementation with brackish water becomes economically advantageous from 0.9, 1.0 and 2.4 ha, respectively, while maize cultivation without SI is not advantageous under the last two scenarios. For severe drought conditions, however, SI using brackish water reduced commercial yield by 27 % with negative effects on the farmers profitability. In this case, it is necessary to use water with either lower salinity or select salt tolerant crops.(AU)

Diet composition of abundant fish species in the shallow waters of the Todos os Santos Bay, Bahia, Brazil

Coastal habitats have great ecological importance with estuarine environments providing feeding sites for many fish species, especially during juvenile life stages. This study investigates the diet composition and trophic guild organization of the common and abundant ichthyofauna in shallow areas of the Todos os Santos Bay (TSB), Bahia, Brazil, and their relationships with environmental parameters. Six fish sampling campaigns were carried out in the shallow zones (infralittoral) of the Paraguaçu River estuary which encompasses the inner and outer (marine exposure) reaches of theTSB. The stomach contents of 1231 individualsbelonging to common and abundant species were examined. A total of 32 food items were identifiedand fish were into four trophic guilds: detritivores, zoobenthivores I, zoobenthivores II, and zooplanktivores. The relationship between the guilds and environmental parameters showed that zoobenthivores II and zooplanktivores guilds had a positive relationship with salinity and pH, explaining 86% of data variability, though only the salinity variable was significant. This study provides basic information about the diet composition of common and abundant species in the TSBand their organization into trophic guilds. In addition, demonstrates that shallow waters fish across all guilds have broadly similar diets, comprising food items that are usually associated with bottom waters.

Diet composition of abundant fish species in the shallow waters of the Todos os Santos Bay, Bahia, Brazil

Coastal habitats have great ecological importance with estuarine environments providing feeding sites for many fish species, especially during juvenile life stages. This study investigates the diet composition and trophic guild organization of the common and abundant ichthyofauna in shallow areas of the Todos os Santos Bay (TSB), Bahia, Brazil, and their relationships with environmental parameters. Six fish sampling campaigns were carried out in the shallow zones (infralittoral) of the Paraguaçu River estuary which encompasses the inner and outer (marine exposure) reaches of theTSB. The stomach contents of 1231 individualsbelonging to common and abundant species were examined. A total of 32 food items were identifiedand fish were into four trophic guilds: detritivores, zoobenthivores I, zoobenthivores II, and zooplanktivores. The relationship between the guilds and environmental parameters showed that zoobenthivores II and zooplanktivores guilds had a positive relationship with salinity and pH, explaining 86% of data variability, though only the salinity variable was significant. This study provides basic information about the diet composition of common and abundant species in the TSBand their organization into trophic guilds. In addition, demonstrates that shallow waters fish across all guilds have broadly similar diets, comprising food items that are usually associated with bottom waters.(AU)

Reproductive cycle of native viviparous fish species (Actinopterygii: Cyprinodontiformes: Goodeidae) in a subtropical Mexican lake

Reproductive tactics and strategies contribute to the persistence and maintenance of long-term populations in fish species. Members of the subfamily Goodeinae are a group of small-bodied freshwater fish with specialized reproduction (viviparity-matrotrophy). They are found in the highlands of central Mexico, most of them endemic. The aim of this study was to conduct a comprehensive investigation to evaluate the annual reproductive cycle of seven species of goodeines (splitfins). We carried out our study in the subtropical Lake Zacapu, Mexico, with bi-monthly sampling from May 2019 to March 2020. We obtain the fertility, size at first maturity (L50), sex ratio, and gonadosomatic index. Our result shows that populations of goodeines have high fertility compared to other populations of the same species in other aquatic systems and also to other species of goodein. We found that males mature at smaller sizes than females, the observed proportion of females was greater than males in all the goodeines. Lake Zacapu goodeines have two reproductive peaks, one in spring (April to June) and another in fall (September to November). These tactics (fertility rates, sex ratio, reproductive period) and strategies (viviparity-matrotrophy) favor reproductive success in this environmentally stable subtropical lake in the highlands of Mexico.(AU)

Las tácticas y estrategias reproductivas contribuyen a la persistencia y el mantenimiento de las poblaciones a largo plazo en especies de peces. Miembros de la subfamilia Goodeinae son un grupo de peces de agua dulce con reproducción especializada (viviparidad-matrotrofia). Se encuentran en el centro de México, la mayoría de ellos endémicos. El objetivo de este estudio fue realizar una investigación integral para evaluar el ciclo reproductivo anual de siete especies de goodeines o mexclapiques. Realizamos nuestro estudio en el lago subtropical de Zacapu, México, con muestreo bimestral de mayo de 2019 a marzo de 2020. Nuestros resultados muestran que las poblaciones de goodeines tienen una alta fertilidad en comparación con otras poblaciones de la misma especie en otros sistemas acuáticos y también con otras especies de goodeines. Encontramos que los machos maduran en tamaños más pequeños que las hembras, la proporción observada de hembras fue mayor que los machos en todas las goodeines. Los goodeines del lago Zacapu tienen dos picos reproductivos, uno en primavera (abril a junio) y otro en otoño (septiembre a noviembre). Estas tácticas (fertilidad, proporción de sexos, período reproductivo) y estrategias (viviparidad-matrotrofia) favorecen el éxito reproductivo en este lago subtropical ambientalmente estable en el altiplano de México.(AU)

Reproductive cycle of native viviparous fish species (Actinopterygii: Cyprinodontiformes: Goodeidae) in a subtropical Mexican lake

Reproductive tactics and strategies contribute to the persistence and maintenance of long-term populations in fish species. Members of the subfamily Goodeinae are a group of small-bodied freshwater fish with specialized reproduction (viviparity-matrotrophy). They are found in the highlands of central Mexico, most of them endemic. The aim of this study was to conduct a comprehensive investigation to evaluate the annual reproductive cycle of seven species of goodeines (splitfins). We carried out our study in the subtropical Lake Zacapu, Mexico, with bi-monthly sampling from May 2019 to March 2020. We obtain the fertility, size at first maturity (L50), sex ratio, and gonadosomatic index. Our result shows that populations of goodeines have high fertility compared to other populations of the same species in other aquatic systems and also to other species of goodein. We found that males mature at smaller sizes than females, the observed proportion of females was greater than males in all the goodeines. Lake Zacapu goodeines have two reproductive peaks, one in spring (April to June) and another in fall (September to November). These tactics (fertility rates, sex ratio, reproductive period) and strategies (viviparity-matrotrophy) favor reproductive success in this environmentally stable subtropical lake in the highlands of Mexico.(AU)

Las tácticas y estrategias reproductivas contribuyen a la persistencia y el mantenimiento de las poblaciones a largo plazo en especies de peces. Miembros de la subfamilia Goodeinae son un grupo de peces de agua dulce con reproducción especializada (viviparidad-matrotrofia). Se encuentran en el centro de México, la mayoría de ellos endémicos. El objetivo de este estudio fue realizar una investigación integral para evaluar el ciclo reproductivo anual de siete especies de goodeines o mexclapiques. Realizamos nuestro estudio en el lago subtropical de Zacapu, México, con muestreo bimestral de mayo de 2019 a marzo de 2020. Nuestros resultados muestran que las poblaciones de goodeines tienen una alta fertilidad en comparación con otras poblaciones de la misma especie en otros sistemas acuáticos y también con otras especies de goodeines. Encontramos que los machos maduran en tamaños más pequeños que las hembras, la proporción observada de hembras fue mayor que los machos en todas las goodeines. Los goodeines del lago Zacapu tienen dos picos reproductivos, uno en primavera (abril a junio) y otro en otoño (septiembre a noviembre). Estas tácticas (fertilidad, proporción de sexos, período reproductivo) y estrategias (viviparidad-matrotrofia) favorecen el éxito reproductivo en este lago subtropical ambientalmente estable en el altiplano de México.(AU)

Molecular identification of Brachygenys and Haemulon species (Perciformes: Haemulidae) from the Brazilian coast

The fishes of the Haemulidae family are currently allocated to 19 genera with a worldwide distribution in the tropical and subtropical waters of the world's oceans. Brachygenys and Haemulon are important genera of reef fish in Brazil, as they occur in large shoals, which are both ecologically and commercially valuable. This study identified the Brazilian species of the genera Brachygenys and Haemulon using DNA barcodes. While we found only a single lineage in Brachygenys chrysargyrea, Haemulon melanurum, H. parra, and H. squamipinna, more than one molecular operational taxonomic unit (MOTU) was identified in H. atlanticus, H. aurolineatum, and H. plumieri, indicating the possible existence of discrete populations or cryptic species.(AU)

Os peixes da família Haemulidae estão atualmente distribuídos em 19 gêneros, com distribuição mundial em águas oceânicas tropicais e subtropicais. Brachygenys e Haemulon são importantes gêneros de peixes recifais do Brasil, visto que ocorrem em grandes cardumes, de valores ecológicos e comerciais. Este estudo identificou as espécies brasileiras dos gêneros Brachygenys e Haemulon usando o código de barras de DNA. Embora apenas uma única linhagem de Brachygenys chrysargyrea, Haemulon melanurum, H. parra e H. squamipinna tenha sido encontrada em nosso conjunto de dados, mais de uma unidade taxonômica operacional molecular (MOTU) foi identificada em H. atlanticus, H. aurolineatum e H. plumieri, indicando a possível existência de populações discretas ou espécies crípticas.(AU)

Molecular identification of Brachygenys and Haemulon species (Perciformes: Haemulidae) from the Brazilian coast

The fishes of the Haemulidae family are currently allocated to 19 genera with a worldwide distribution in the tropical and subtropical waters of the world's oceans. Brachygenys and Haemulon are important genera of reef fish in Brazil, as they occur in large shoals, which are both ecologically and commercially valuable. This study identified the Brazilian species of the genera Brachygenys and Haemulon using DNA barcodes. While we found only a single lineage in Brachygenys chrysargyrea, Haemulon melanurum, H. parra, and H. squamipinna, more than one molecular operational taxonomic unit (MOTU) was identified in H. atlanticus, H. aurolineatum, and H. plumieri, indicating the possible existence of discrete populations or cryptic species.(AU)

Os peixes da família Haemulidae estão atualmente distribuídos em 19 gêneros, com distribuição mundial em águas oceânicas tropicais e subtropicais. Brachygenys e Haemulon são importantes gêneros de peixes recifais do Brasil, visto que ocorrem em grandes cardumes, de valores ecológicos e comerciais. Este estudo identificou as espécies brasileiras dos gêneros Brachygenys e Haemulon usando o código de barras de DNA. Embora apenas uma única linhagem de Brachygenys chrysargyrea, Haemulon melanurum, H. parra e H. squamipinna tenha sido encontrada em nosso conjunto de dados, mais de uma unidade taxonômica operacional molecular (MOTU) foi identificada em H. atlanticus, H. aurolineatum e H. plumieri, indicando a possível existência de populações discretas ou espécies crípticas.(AU)

Patterns of ichthyofaunal diversity and distribution across Jebba Hydro-Electric Power (HEP) dam, Jebba, north-central Nigeria / Padrões de diversidade e distribuição da ictiofauna na barragem de hidroelétricas (HEP) de Jebba, Jebba, Nigéria norte-central

The ichthyofauna diversity of the Jebba Hydroelectric Power (HEP) Dam, Jebba, North-central Nigeria was studied. Fishes were sampled for 24 months using gill net, hook and line, and cast net. Individuals were identified using morphological and molecular (mitochondrial Cytochrome c Oxidase subunit I) data. A total of 9605 freshwater fishes were recorded during the sampling period. The use of an integrative taxonomic approach enabled the identification of 83 species belonging to 42 genera. Additionally, the study recorded three unidentified species ­ Ctenopoma sp, Malapterurus sp., and Protopterus sp. Analyses showed that individuals belonging to families Cichlidae and Mochokidae dominated the dam. The diversity analyses revealed relatively high fish diversity during the rainy season at the downstream section of Jebba HEP dam compared to the upstream section. The study, therefore, showed the presence of a diverse fish community comprising high species richness and diversity across the Jebba HEP dam. Finally, we recommend proper biodiversity monitoring and assessment of freshwater fish diversity across Nigeria. In addition, the use of an integrated taxonomic approach is recommended for appropriate species' identification and studies of freshwater fishes from Nigeria.

A diversidade da ictiofauna da hidrelétrica de Jebba (HEP), Jebba, centro-norte da Nigéria foi estudada. Os peixes foram amostrados por 24 meses, utilizando rede de emalhar, anzol e linha, e rede de arrasto. Os indivíduos foram identificados usando a abordagem combinada morfológica e molecular (citocromo c Oxidase mitocondrial subunidade I). Um total de 9605 peixes de água doce foram registrados durante o período de amostragem. A identificação das espécies utilizando a abordagem taxonômica integrada possibilitou a identificação de 83 espécies pertencentes a 42 gêneros. Além disso, o estudo registrou três espécies não identificadas - Ctenopoma sp, Malapterurus sp e Protopterus sp. Análises mostraram que indivíduos pertencentes às famílias Cichlidae e Mochokidae dominaram a barragem. As análises dos índices de diversidade revelaram uma diversidade de peixes relativamente alta durante a estação chuvosa na seção a jusante da barragem Jebba HEP em comparação com a seção a montante. O estudo mostrou, portanto, a presença de diversas comunidades de peixes, que incluem alta riqueza e diversidade de espécies através da barragem Jebba HEP. Finalmente, recomendamos o monitoramento adequado da biodiversidade e a avaliação da diversidade de peixes de água doce em toda a Nigéria. Além disso, recomenda-se o uso de abordagem taxonômica integrada para a identificação adequada das espécies e estudos de peixes de água doce da Nigéria.

DNA barcoding of a tropical anguillid eel, Anguilla bicolor (Actinopterygii: Anguilliformes), in Indo-Pacific region and notes on its population structure

The tropical anguillid eel, Anguilla bicolor McCelland, 1844, includes two subspecies, Anguilla bicolor bicolor McCelland, 1844 and Anguilla bicolor pacifica Schmidt, 1928, and is distributed across the Indo-Pacific region. Although A. bicolor is widely distributed and recognized as an important fish resource in the Indo-Pacific region, few studies have been conducted on its genetic variation and population structure. DNA barcoding of A. bicolor specimens collected in the Indo-Pacific region was carried out in this study using mitochondrial cytochrome c oxidase subunit I. Anguilla bicolor was found to diverge genetically, which supported its classification into two different subspecies. In addition, our study showed that A. bicolor bicolor had two genetically distinct populations/groups, and these different populations co-occur geographically in Indonesia and Malaysia in the eastern Indian Ocean. Our findings suggest that the eel larvae might be transported from at least two geographically different spawning grounds in the Indian Ocean, and then recruited to and settled in the same habitats in Indonesian and Malaysian waters. The molecular evidence calls for further research on the life history, stock assessment and protection of the populations of A. bicolor bicolor in Indonesia and Malaysia.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.(AU)

Kajikia audax, Thunnus albacares, Katsuwonus pelamis e Auxis spp. ocupam posições tróficas intermedias e/ou elevadas nas cadeias alimentares. Estas espécies representam um importante recurso pesqueiro no Ecuador. Apesar da sua importância económica e ecológica, estudos nestas espécies pelágicas no Ecuador são raras. Este estudo usa isótopos estáveis para avaliar o seu nível trófico de modo a determinar a contribuição das suas presas para os tecidos destes predadores. Dados dos isótopos foram usados para testar a hipótese de que estas espécies de peixes pelágicos possuem valores mais elevados de δ15N do que daqueles das presas consumidas, e que não existe uma sobreposição entre os valores de δ13C e δ15N. Resultados mostram que valores mais elevados de δ15N para K. audax, seguidos por T. albacares, Auxis spp. e K. pelamis, indicam que a posição mais elevada na cadeia alimentar é ocupada por K. audax. Elipses Bayesianas de isótopos estáveis demonstram que, a uma escala de longo-termo, estas espécies de peixes não competem pelos recursos. Adicionalmente, os valores de δ15N são diferentes entre espécies de peixe estudadas e estes valores decrescem com a diminuição do tamanho do predador.(AU)

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.(AU)

Kajikia audax, Thunnus albacares, Katsuwonus pelamis e Auxis spp. ocupam posições tróficas intermedias e/ou elevadas nas cadeias alimentares. Estas espécies representam um importante recurso pesqueiro no Ecuador. Apesar da sua importância económica e ecológica, estudos nestas espécies pelágicas no Ecuador são raras. Este estudo usa isótopos estáveis para avaliar o seu nível trófico de modo a determinar a contribuição das suas presas para os tecidos destes predadores. Dados dos isótopos foram usados para testar a hipótese de que estas espécies de peixes pelágicos possuem valores mais elevados de δ15N do que daqueles das presas consumidas, e que não existe uma sobreposição entre os valores de δ13C e δ15N. Resultados mostram que valores mais elevados de δ15N para K. audax, seguidos por T. albacares, Auxis spp. e K. pelamis, indicam que a posição mais elevada na cadeia alimentar é ocupada por K. audax. Elipses Bayesianas de isótopos estáveis demonstram que, a uma escala de longo-termo, estas espécies de peixes não competem pelos recursos. Adicionalmente, os valores de δ15N são diferentes entre espécies de peixe estudadas e estes valores decrescem com a diminuição do tamanho do predador.(AU)