Abstract Aim This study aimed to evaluate the spatial and temporal distribution of ichthyoplankton in the Peri Lagoon, a coastal freshwater lagoon in Brazil. Methods Ichthyoplankton samples were collected every two months from June 2008 to April 2010 with 500 µm conical-cylindrical planktonic nets at five sampling stations. Results In total, 181 fish eggs and 1,315 larvae, representing estuarine and freshwater species, were captured. The most representative species were Awaous tajasica, Ctenogobius sp1, and Platanichthys platana. Significant differences were found in temporal egg distribution and larval spatiotemporal distribution (Kruskal-Wallis test, p < 0.05). Eggs were predominantly captured during the autumn, winter, and spring Neotropical seasons. Geospatial analysis demonstrated spatial segregation in the distribution of larval assemblages, with higher abundances in areas adjacent to riparian forests, following stream mouths, and deeper areas with rocky substrates. Conclusions Proximity to streams and areas surrounded by dense forests is crucial for the spawning and development of fish species in the Peri Lagoon. The findings of this study provide valuable insights into the conservation of the ichthyofauna in this unique environment. Lagoon Brazil 200 201 50 conicalcylindrical conical cylindrical stations total 18 1315 1 315 1,31 larvae tajasica sp1 sp platana KruskalWallis Kruskal Wallis test 0.05. 005 0.05 . 0 05 0.05) autumn winter seasons assemblages mouths substrates environment 20 5 131 31 1,3 00 0.0 2 13 3 1, 0.

Resumo Objetivo Este estudo teve como objetivo avaliar a distribuição espacial e temporal do ictioplâncton na lagoa do Peri, uma lagoa costeira de água doce no Brasil. Método s: O ictioplâncton foi coletado bimestralmente de junho de 2008 a abril de 2010 com redes cônico-cilíndricas planctônicas de 500 µm em cinco estações de amostragem. Resultados Neste estudo, foram capturados 181 ovos e 1.316 larvas de peixes de espécies estuarinas e de água doce. As espécies mais representativas foram Awaous tajasica, Ctenogobius sp1 e Platanichthys platana. O teste de Kruskal-Wallis (H) indicou que existem diferenças significativas na distribuição temporal dos ovos e na distribuição espaço-temporal das larvas (p<0,05). Em geral, os ovos foram capturados durante as estações de outono, inverno e primavera na Região Neotropical. A relevância do fator geoespacial mostrou segregação espacial na assembleia de larvas. As larvas foram capturadas em ambientes cercados por mata ciliar, próximo à foz de córregos, em áreas mais profundas com fundo rochoso. Conclusões Regiões próximas a córregos e cercadas por florestas densas parecem ser essenciais para a desova e desenvolvimento de espécies de peixes na lagoa do Peri. Este estudo pode orientar importantes diretrizes ambientais para a preservação da ictiofauna desse ambiente intocado e particular. Peri Brasil s 200 201 cônicocilíndricas cônico cilíndricas 50 amostragem 18 1316 1 316 1.31 tajasica sp platana KruskalWallis Kruskal Wallis H (H espaçotemporal espaço p<0,05. p005 p p<0,05 . 0 05 (p<0,05) geral outono Neotropical ciliar rochoso particular 20 5 131 31 1.3 p00 p<0,0 (p<0,05 2 13 3 1. p0 p<0, (p<0,0 p<0 (p<0, p< (p<0 (p< (p

Abstract The conservation of fish assemblages depends on the longitudinal and lateral connectivity between riverine habitats, in particular during the breeding season and the initial development. This study investigated the composition and spatio-temporal structure in the ichthyoplankton of the hydrographic basin of the Paraguay River in western Brazil to identify the local spawning grounds and the importance of the longitudinal connectivity of economically valuable migratory species. Data were collected at 10 sites between two breeding seasons (2017/2018 and 2018/2019). Were collected 8,635 larvae, representing 55 taxa in 25 families, including the migratory species Brycon hilarii, Hemisorubim platyrhynchos, Piaractus mesopotamicus, Prochilodus lineatus, Pseudoplatystoma spp., Salminus brasiliensis, Sorubim lima, and Zungaro jahu, which are important fishery resources, with the highest larval densities being recorded between November and January. The Sepotuba, Paraguay, Jauru, and Cabaçal rivers were the areas of greatest connectance, and should thus be considered critical for the conservation of the longitudinal connectivity of this fluvial system, indicating that the migratory species spawn upriver. More efficient fisheries management mechanisms are needed, respecting the spawning period of migratory species, maintaining quality and longitudinal connectivity between habitats, and characteristics necessary for successful larval recruitment. habitats development spatiotemporal spatio temporal 1 2017/2018 20172018 2017 2018 (2017/201 2018/2019. 20182019 2018/2019 . 2019 2018/2019) 8635 8 635 8,63 larvae 5 2 families hilarii platyrhynchos mesopotamicus lineatus spp spp. brasiliensis lima jahu resources January Sepotuba Jauru connectance system upriver needed recruitment 2017/201 2017201 201 (2017/20 2018201 2018/201 863 63 8,6 2017/20 201720 20 (2017/2 201820 2018/20 86 6 8, 2017/2 20172 (2017/ 20182 2018/2 2017/ (2017 2018/ (201 (20 (2 (

Resumo A conservação das assembleias de peixes depende da conectividade longitudinal e lateral entre habitats ribeirinhos, em especial durante o período reprodutivo e de desenvolvimento inicial. Objetivou-se avaliar a composição e a estrutura espaço-temporal do ictioplâncton da bacia hidrografia do rio Paraguai no oeste do Brasil para identificar as áreas de desova e a importância da conectividade longitudinal para a reprodução das espécies migradoras de interesse comercial. Os dados foram coletados em 10 pontos entre dois períodos reprodutivos (2017/2018 e 2018/2019). Capturaram-se 8635 larvas, pertencentes a 25 famílias e 55 táxons, incluindo espécies migradoras de interesse comercial, Brycon hilarii, Hemisorubim platyrhynchos, Piaractus mesopotamicus, Prochilodus lineatus, Pseudoplatystoma spp., Salminus brasiliensis, Sorubim lima e Zungaro jahu, que são importantes recursos pesqueiros, com maiores densidades larvais entre novembro e janeiro. Os locais com maiores interações e conectância foram os rios Sepotuba, Paraguai, Jauru e Cabaçal e, portanto, devem ser considerados áreas críticas para a conservação da conectividade longitudinal no sistema fluvial, indicando que as espécies migradoras têm desovado a montante dos locais amostrados. São necessários mecanismos de gestão pesqueira mais eficientes, respeitando o período de desova das espécies migradoras, mantendo a qualidade e conectividade longitudinal entre habitats, características necessárias ao sucesso do recrutamento larval. ribeirinhos inicial Objetivouse Objetivou se espaçotemporal espaço temporal comercial 1 2017/2018 20172018 2017 2018 (2017/201 2018/2019. 20182019 2018/2019 . 2019 2018/2019) Capturaramse Capturaram 863 larvas 2 5 táxons hilarii platyrhynchos mesopotamicus lineatus spp spp. brasiliensis jahu pesqueiros janeiro Sepotuba portanto fluvial amostrados eficientes larval 2017/201 2017201 201 (2017/20 2018201 2018/201 86 2017/20 201720 20 (2017/2 201820 2018/20 8 2017/2 20172 (2017/ 20182 2018/2 2017/ (2017 2018/ (201 (20 (2 (

Abstract The early development of Markiana nigripinnis is described by morphological characters, pigmentation, and morphometry. Larvae were obtained through semi-natural breeding, collected, fixed, and identified according to their development. Eighty individuals with standard lengths ranging from 3.1 to 24.3 mm were analyzed. Larvae are poorly developed at hatching, with a relatively large yolk sac and finfold. At the preflexion stage, the eyes are pigmented, the mouth and anus are functional, the yolk is completely absorbed, and the pectoral fin bud emerges. At flexion, the first rays of the caudal, anal, and dorsal fins become evident. The pelvic fin bud emerges only at the postflexion stage, in addition to the complete absorption of the finfold. Pigmentation is distributed throughout the body, with a greater concentration on the top of the head, around the mouth, and at the base of the caudal fin. The myomere total number ranged from 34 to 49 (16–23 preanal, and 18–27 postanal). Juveniles show morphological characteristics like adults. The fins ray number are pectoral: 11–13, pelvic: 5–7, dorsal: 8–11, caudal: 16–27, and anal 30–47. The morphometric relationships reveal variations in growth along the early ontogeny of the species. characters pigmentation morphometry seminatural semi natural breeding collected fixed 31 3 1 3. 243 24 24. analyzed hatching finfold stage pigmented functional absorbed flexion evident body head 4 16–23 1623 16 23 (16–2 preanal 1827 18 27 18–2 postanal. postanal . postanal) adults 1113 11 13 11–13 57 5 7 5–7 811 8 8–11 1627 16–27 3047 30 47 30–47 species 2 16–2 162 (16– 182 18– 111 11–1 5– 81 8–1 304 30–4 16– (16 11– 8– 30– (1 (

Resumo O desenvolvimento inicial de Markiana nigripinnis foi descrito considerando os caracteres morfológicos, a pigmentação e a morfometria. Indivíduos foram obtidos por meio de reprodução seminatural, coletados, acondicionados, fixados e identificados conforme seu período e estágio de desenvolvimento. Foram analisados 80 indivíduos com comprimento padrão variando de 3,1 a 24,3 mm. As larvas são pouco desenvolvidas à eclosão, com saco vitelino relativamente grande e presença de membrana embrionária. Em pré-flexão, os olhos estão pigmentados, a boca e o ânus são funcionais, o vitelo é completamente absorvido e surge o botão da nadadeira peitoral. Em flexão, os primeiros raios das nadadeiras caudal, anal e dorsal tornam-se evidentes. O botão da nadadeira pélvica aparece somente em pós-flexão, além da completa absorção da nadadeira embrionária. A pigmentação se distribui pelo corpo todo, com maior concentração no topo da cabeça, ao redor da boca e na base da nadadeira caudal. O número total de miômeros variou de 34 a 49 (16–23 pré e 18–27 pós-anal). Os juvenis apresentaram características morfológicas semelhantes ao adulto. O número de raios das nadadeiras é peitoral: 11–13, pélvica: 5–7, dorsal: 8–11, caudal: 16–27 e anal 30–47. As relações morfométricas revelam variações no crescimento ao longo da ontogenia inicial da espécie. morfológicos morfometria seminatural coletados acondicionados 8 31 3 1 3, 243 24 24, mm eclosão embrionária préflexão, préflexão flexão pré-flexão pigmentados funcionais peitoral caudal tornamse tornam evidentes pósflexão, pósflexão pós pós-flexão todo cabeça 4 16–23 1623 16 23 (16–2 1827 18 27 18–2 pósanal. pósanal . pós-anal) adulto 1113 11 13 11–13 57 5 7 5–7 811 8–11 1627 16–2 3047 30 47 30–47 espécie 2 162 (16– 182 18– pós-anal 111 11–1 5– 81 8–1 16– 304 30–4 (16 11– 8– 30– (1 (

RESUMO Os estuários hipersalinos são comumente encontrados na região semiárida da costa nordestina brasileira. No entanto, a utilização desses estuários pelos primeiros estágios de vida dos peixes é pouco documentada. O objetivo deste estudo foi avaliar os efeitos de fatores ambientais sobre o ictioplâncton e descrever sua variação espacial e temporal em dois estuários (Tubarão e Casqueira). As amostragens foram diurnas em quatro excursões realizadas em dois meses da estação seca (novembro e dezembro de 2017) e dois meses da estação chuvosa (maio e julho de 2018). Um total de 423 larvas representando 30 espécies (14 famílias) e 2.762 ovos (cinco famílias) foram coletadas. Embora as estruturas das comunidades fossem semelhantes em ambos os estuários, houve fortes diferenças de variação sazonal, com maiores abundâncias observadas durante a estação seca. A baixa precipitação foi o principal fator ambiental que afetou o ictioplâncton em ambos os estuários. Outros fatores, como profundidade, temperatura da água e largura do canal, também foram preditoras para a distribuição de ovos e larvas. O ictioplâncton foi dominado por espécies marinhas dependentes em ambos os estuários, representando 76% dos indivíduos. A presença de estágios iniciais de espécies tipicamente marinhas sugere que ambientes hipersalinos fornecem áreas de berçário importantes e desempenham um papel essencial para algumas espécies de peixes costeiros.

ABSTRACT Hypersaline estuaries are commonly found in the Semiarid Northeast Brazilian coast. However, the utilization of these estuaries by early life stages of fishes is less well documented. This study aimed to evaluate the effects of environmental factors on the ichthyoplankton, and to describe their spatial and temporal variation in two estuaries (Tubarão and Casqueira). The sampling were diurnally in four excursions carried out during two dry-season months (November and December 2017) and two rainy-season months (May and July 2018). A total of 423 larvae representing 30 species (14 families) and 2,762 eggs (five families) were collected. Although the community structures were similar in both estuaries, there was strong seasonal variation, with higher abundances observed during the dry season. Low rainfall was the primary environmental driver affecting ichthyoplankton in both estuaries. Other environmental factors, such as depth, water temperature, and channel width, were also predictor variables for the distribution of eggs and larvae. The ichthyoplankton was dominated by marine estuarine-dependent species in both estuaries, accounting for 76% of individuals. The presence of the early life stages of typically marine species suggests that hypersaline environments provide important nursery areas and play an essential role for some coastal fish species.

Resumo Evidências indicam que os peixes migradores se reproduzem no médio rio Uruguai, mas a localização dos locais de desova ainda permanece desconhecida. Para identificar estes locais, foram realizadas mensalmente entre outubro de 2016 e janeiro de 2017, amostragens de ovos e larvas de peixes em três seções ao longo do médio rio Uruguai, cobrindo dois ambientes: o canal principal e a foz dos afluentes (rios Comandaí, Ijuí e Piratinim). Foram capturados 11.519 ovos e 3.211 larvas, pertencentes a dez espécies migradoras. Ovos e larvas de peixes migradores, foram amplamente distribuídos, com predomínio de ovos segmentados e larvas em estágios de larval-vitelino e pré-flexão, com maiores densidades próximo à confluência com o rio Piratinim. As assembleias de larvas mostraram variação espacial, indicando que os locais de desova diferem entre as espécies migradoras. Este estudo fornece novas informações sobre a reprodução de peixes no médio rio Uruguai, revelando que espécies migradoras desovam em diferentes localidades ao longo do canal principal e afluentes. Esta região pode funcionar como um local crítico para a reprodução de peixes, embora atualmente esteja ameaçada pelo risco de expansão da energia hidrelétrica, enfatizando a necessidade de medidas que preservem suas condições ambientais, conectividade hidrológica e funções ecológicas.

Abstract Evidence indicates that migratory fish reproduce in the middle Uruguay River, but the location of spawning sites remains unknown. To identify spawning sites in the basin, fish eggs and larvae were sampled monthly between October 2016 and January 2017. The sampling was carried out in three sections along the middle Uruguay River, covering two environments: the main channel and the mouth of tributaries (Comandaí, Ijuí, and Piratinim rivers). A total of 11,519 eggs and 3,211 larvae were captured, belonged to ten migratory species. Eggs and larvae of migratory fishes, were widely distributed, with predominance of segmented eggs, and larvae in yolk-sac and pre-flexion stages, with higher densities near the confluence with the Piratinim River. Larvae assemblages showed spatial variation, indicating that spawning sites differ among migratory species. This study provides new information about fish reproduction in the middle Uruguay River, revealing that migratory species spawn in different localities along the main channel and tributaries. This region may function as a critical site for fish reproduction, although it is currently threatened by the risk of hydropower expansion, emphasizing the need for measures that preserve their environmental conditions, hydrological connectivity and ecological functions.

RESUMEN Con el propósito de caracterizar el ictioplancton en tres áreas marinas protegidas (Parque Nacional Natural Sanquianga, Parque Nacional Natural Gorgona y Santuario de Fauna y Flora Malpelo) en el Pacífico colombiano durante noviembre de 2009, se realizaron expediciones científicas para obtener 56 muestras mediante el arrastre con redes bongo. Se capturaron 3155/10 m2 larvas de peces distribuidas en 1553 larvas/10 m2 (49,22 %) para el PNN Sanquianga; 1411 larvas/10 m2 (44,72 %) para el PNN Gorgona y 191 larvas/10 m2 (6,05 %) para el SFF Malpelo. Las principales familias fueron Engraulidae (PNN Sanquianga), Bregmacerotidae (PNN Gorgona) y Phosichthyidae (SFF Malpelo). El análisis de comunidades evidencia que la ubicación de las áreas, PNN Sanquianga (costera), PNN Gorgona (intermedia) y SFF Malpelo (oceánica), marca una clara diferencia en la composición, distribución y abundancia de las larvas. Se encontraron por primera vez huevos de la familia Engraulidae en el área de Malpelo, no habitual en su distribución, coincidiendo con lo registrado por el Boletín de Alerta Climática (BAC, 2009) de julio de 2009, que plantea el desarrollo de un evento El Niño, que se extendió hasta el primer trimestre de 2010.

ABSTRACT With the purpose of characterizing ichthyoplankton in three marine protected areas (Sanquianga National Natural Park, Gorgona National Natural Park and Malpelo Fauna and Flora Sanctuary) in the Colombian Pacific during November 2009, scientific expeditions were carried out to obtain 56 samples by trawling with bongo nets. 3,155 / 10 m2 fish larvae were captured distributed in 1,553 larvae / 10 m2 (49.22 %) for the PNN Sanquianga; 1,411 larvae / 10m2 (44.72 %) for the Gorgona PNN and 191 larvae / 10m2 (6.05 %) for the Malpelo SFF. The main families were Engraulidae (PNN Sanquianga), Bregmacerotidae (PNN Gorgona) and Phosichthyidae (SFF Malpelo). The NMS community analysis shows that the location of the PNN Sanquianga (coastal), PNN Gorgona (intermediate) and SFF Malpelo (oceanic) areas, marks a clear difference in the composition, distribution and abundance of the larvae. Eggs of Engraulidae were found for the first time in the Malpelo area, an unusual area in its distribution, coinciding with what was reported by the Climate Alert Bulletin (BAC, 2009) of July 2009, which reports the development of an El Niño event, which lasted until the first quarter of 2010.

Resumo: Investigamos as variações espaciais e temporais na distribuição de ovos e larvas de peixes no rio Guareí, um afluente de fluxo livre localizado na parte superior do Reservatório de Jurumirim, bacia do rio Paranapanema, Brasil. Ovos e larvas de peixes foram amostrados ~ quinzenalmente de novembro de 2017 a março de 2018 (Ciclo 1), e de novembro de 2018 a março de 2019 (Ciclo 2), em três locais distribuídos ao longo de todo o curso do rio Guareí. Foram coletados 859 ovos de peixes e 1.340 larvas, compreendendo 19 táxons. Nós encontramos atividade reprodutiva de várias espécies no rio Guareí, incluindo espécies migradoras de longa distância. Contudo, não houve diferenças espaciais na estrutura das assembleias e nas densidades de ovos e larvas e ao longo do canal do rio Guareí. Diferenças temporais foram significativas apenas para densidade de larvas no Ciclo 2. A captura consistente de ovos e larvas de peixes em dois ciclos reprodutivos é uma forte evidência de que este rio é um local para a reprodução de várias espécies de peixes. Assim, recomendamos a manutenção do seu regime de fluxo natural.

Abstract: We investigated spatial and temporal variations in the distribution of fish eggs and larvae in the Guareí River, a free-flowing tributary located in the upper section of the Jurumirim Reservoir, Paranapanema River, Brazil. Fish eggs and larvae were sampled ~ fortnightly from November 2017 to March 2018 (Cycle 1), and from November 2018 to March 2019 (Cycle 2), at three sites distributed along the entire course of the Guareí River. We collected 859 fish eggs and 1,340 larvae, comprising 19 taxa. We found reproductive activity of several fish species in the Guareí River, including long-distance migrants. However, there was no spatial differences in the assemblage structure and densities of fish eggs and larvae along the channel of Guareí River. We recorded temporal differences in larvae density only in Cycle 2. The consistent capture of fish eggs and larvae in two reproductive cycles is strong evidence that this river is a spawning site for a variety of fish species. Thus, we recommend maintaining its natural flow regime.

Abstract Because dams block migratory routes of potamodromous fish to their spawning areas, and energy generation changes natural flow seasonality, it is necessary to identify spawning areas and their conditions. This information will help in management decisions in the Magdalena River basin regarding the future hydropower development. We identified which characteristics of the tributaries to the Magdalena River are important for determining potamodromous fish spawning grounds, and we estimated the percentage of future loss of spawning areas because of dam development. Ichthyoplankton density is directly related to the floodplain area, and inversely related with channel slope. Low channel slopes offer adult fish a longer distance for their upstream migration and a longer time for embryo development during their drift downstream from the spawning areas to nursery habitats (floodplain lakes). These features could increase the migration distance of the adults, the time for initial embryo development, and, because of its relationship with nursery habitats access, the offspring survival. The potential loss of the actual spawning grounds in the river network was estimated to be nearly 70% because of new dams. Our findings will help to reduce conflicts between hydropower and ecological interests.

Resumen La construcción de hidroeléctricas puede afectar la reproducción de los peces migratorios potamódromos, ya sea porque las represas bloquean las rutas migratorias a sus áreas de desove, o porque la generación de energía cambia la estacionalidad del flujo natural. Esto hace necesario generar información sobre las áreas de desove y sus características, que permitan tomar decisiones de manejo, teniendo en cuenta el desarrollo hidroeléctrico propuesto a futuro en la cuenca del río Magdalena. Identificamos qué características de algunos afluentes del río Magdalena son importantes para los desoves y estimamos el porcentaje de pérdida futura de áreas de desoves debido al desarrollo hidroeléctrico. La densidad del ictioplancton se relacionó directamente con el área de la llanura aluvial e inversamente con la pendiente del canal. Estas características aumentan la distancia de migración de los adultos maduros, el tiempo para el desarrollo inicial del embrión y la supervivencia de la descendencia debido a la proximidad y/o conectividad con los hábitats de cría. La pérdida potencial de las zonas de desove en la red fluvial se estimó en casi el 70% debido a las nuevas presas. Nuestros hallazgos ayudarán a tomar decisiones sostenibles para reducir los conflictos entre intereses de desarrollo hidroeléctrico y ecológicos.

RESUMEN: Se determinó la variación en la estructura del ensamblaje de larvas de peces a lo largo de un gradiente salino en el estuario del río Pánuco, para lo cual se realizaron muestreos en: enero, marzo, mayo, julio, septiembre y noviembre en 2017 en nueve sitios, con una red estándar con abertura de malla de 500 µm. Se recolectaron 1 165 huevos de peces y 526 larvas de peces de 18 especies, tres de ellas de agua dulce. La mayor riqueza de especies se observó en el estuario medio y laguna de Pueblo Viejo. Los valores mayores de diversidad y equidad se presentaron en noviembre (2.7 y 0.9, respectivamente). La dominancia fue mayor en julio (0.4) debido a la abundancia de Anchoa mitchilli. El ensamblaje ictioplanctónico se caracterizó por un mayor número de especies dominantes marinas y estuarinas, un bajo número de dulceacuícolas y disminución de la riqueza río arriba.

ABSTRACT: To determine the structure of the ichthyoplankton assemblage along a saline gradient in the Pánuco river estuary, sampling was performed in: January, March, May, July, September, and November in 2017 at nine sites, with a standard network with a mesh opening of 500 µm. 1 165 eggs and 526 fish larvae were collected from 18 species, three of them from freshwater. The highest specific richness was observed in the middle estuary and lagoon of Pueblo Viejo. The highest values of diversity and evenness was found in November (2.7 and 0.9, respectively). The dominance was greatest in July (0.4) due to the abundance of Anchoa mitchilli. The ichthyoplankton assemblage was characterized by a greater number of dominant marine and estuarine species, a low number of freshwater species and a decrease in species richness upstream.

ABSTRACT Background: Despite the importance of zooplankton communities as a link in the processes of energy flow and biogeochemical cycles, few studies have been conducted in the coastal lagoons of the southwestern Gulf of Mexico, with only two previous formal works for these systems. Objectives: To contribute to the knowledge of the species richness of the coastal zooplankton communities of Veracruz, with particular reference to the La Mancha lagoon. Methods: Monthly samplings were conducted from May 2012 to April 2013, at a site near the mouth of the lagoon, taking diurnal and nocturnal samples in order to have a better representation of the community. Zooplankton samples were collected with a surface net (100 cm length, 150 µm mesh size) in 10 min, circular trawls. Results: Fifty-seven zooplankton components corresponding to 43 families, 25 orders and 6 phyla (Cnidaria, Ctenophora, Chaetognatha, Annelida, Arthropoda y Chordata) were identified. The main components were the crustaceans, within which the adult copepods were the most diverse with 17 species. Adult peracarids were also relatively well represented with 11 species, while the decapods were characterized mainly by larvae (Penaeidea and Brachyura). Ichthyoplankton was represented by 12 species and the rest of the zooplankton included cnidarians, ctenophores, chaetognaths and polychaetes. Eighteen taxa correspond to new records for the system, although only two represent an extension in their range of distribution (Leucon americanus y Microdesmus carri). Conclusions: The zooplanktonic richness recorded in the present study is relatively high, being dominated by copepods. The curve of the accumulation of species and the values of the non-parametric estimators of the richness, allowing us to determine that the number of components recorded in the present study is a good indicator of the zooplankton richness of the study area.

RESUMEN Antecedentes: A pesar de la importancia de las comunidades del zooplancton como moduladores de los procesos de flujo de energía y ciclos biogeoquímicos, pocos estudios se han realizado en lagunas costeras del suroccidente del Golfo de México, existiendo solo dos trabajos formales previos para estos sistemas. Objetivos: Contribuir al conocimiento de la riqueza de especies de las comunidades zooplanctónicas costeras de Veracruz, con particular referencia a la laguna La Mancha. Métodos: Se realizaron muestreos mensuales, de mayo 2012 a abril 2013, en un sitio cercano a la boca de la laguna, tomando muestras diurnas y nocturnas con el fin de tener una mejor representación de la comunidad. El zooplancton fue colectado utilizando una red estándar con luz de malla de 150 µm. Resultados: Se registraron 57 componentes zooplanctónicos correspondientes a 6 phyla (Cnidaria, Ctenophora, Chaetognatha, Annelida, Arthropoda y Chordata), 25 órdenes y 43 familias. Los componentes mejor representados fueron los crustáceos, dentro de los cuales los copépodos adultos fueron los más diversos con 17 especies. Los adultos de peracáridos también estuvieron relativamente bien representados con 11 especies, mientras que los decápodos estuvieron principalmente integrados por larvas (Penaeidea y Brachyura). El ictioplancton estuvo representado por 12 especies y el resto del zooplancton incluyó cnidarios, ctenóforos, quetognatos y poliquetos. Dieciocho taxa corresponden a nuevos registros para el sistema, aunque solo dos representan además una ampliación en su intervalo de distribución (Leucon americanus y Microdesmus carri). Conclusiones: Comparado con otros estudios de diferentes sistemas costeros del Atlántico mexicano, la riqueza zooplanctónica reportada en el presente estudio es relativamente alta, estando dominada por copépodos. La curva de acumulación de especies y los valores de los estimadores no-paramétricos de la riqueza de especies, indican que el número de componentes registrados representa adecuadamente la comunidad zooplanctónica del área estudiada.

RESUMEN Este estudio presenta la densidad, composición taxonómica, distribución espacial y temporal de larvas de peces en el golfo de Guayaquil, así como la relación con algunas variables físico-químicas. Se recolectaron muestras en 16 estaciones, tomadas en la primera milla náutica del estuario externo e interior del golfo, ubicadas frente a la provincia de Guayas y noroeste de la isla Puná, durante junio a diciembre de 2012. Se realizaron arrastres superficiales con una red cónica simple (ojo de malla: 300 μm; diámetro de boca: 0,3 m; largo: 1,2 m). La temperatura, salinidad y transparencia fueron medidas antes de cada arrastre. Se detectaron diferencias significativas entre zonas, registrando mayor temperatura, menor salinidad y transparencia en el estuario interior. Se colectaron 321 638 ind/100m3 de larvas de peces, pertenecientes a 13 familias y 36 especies entre la zona externa e interna. Engraulidae (58,9 %) fue la familia más abundante en las estaciones del estuario exterior, seguida de Sciaenidae (22,8 %) y Haemulidae (9,6 %). Las familias más frecuentes en el estuario interior fueron Engraulidae (74,4 %) y Gobiidae (16,1 %). El 85 % de la densidad total fue aportada por cinco especies, de las cuales Anchoa sp. y Bairdiella sp. fueron las más abundantes y dominantes, principalmente durante diciembre. La estructura y composición de la comunidad larvaria fue significativamente diferentes entre áreas (MW-U = 450; p < 0,05) y meses de muestreo (KW = 14,24; p < 0,05), con mayores registros en el estuario exterior durante diciembre. Con el análisis de redundancia (ADR) se observa que, en el área externa, las especies estuvieron asociadas con la transparencia del agua, mientras que las especies que concurrieron en la zona interna se relacionaron positivamente con la salinidad. En términos generales, la abundancia y riqueza de larvas de peces en el área externa del golfo de Guayaquil está relacionada con las condiciones de transparencia y salinidad local, las cuales favorecieron a la presencia larval.

ABSTRACT This study presents the density, taxonomic composition, spatial and temporal distribution of fish larvae in the Gulf of Guayaquil, as well as the relationship with some physical-chemical variables. Samples were collected at 16 stations, taken in the first nautical mile of the external and internal estuary of the gulf, located in front of the province of Guayas and northwest of the island of Puná, during June to December 2012. Surface trawls were carried out with a simple conical network (mesh eye: 300 μm; mouth diameter: 0.3 m; length: 1.2 m). Temperature, salinity, and transparency were measured before each drag. Significant differences were detected between zones, registering higher temperatures, lower salinity, and transparency in the interior estuary. 321 638 ind/100m3 of fish larvae were collected, belonging to 13 families and 36 species between the external and internal zone. Engraulidae (58.9 %) was the most abundant family in the exterior estuary stations, followed by Sciaenidae (22.8 %) and Haemulidae (9.6 %). Most frequent families in the interior estuary were Engraulidae (74.4 %) and Gobiidae (16.1 %). 85 % of the total density was contributed by five species, of which Anchoa sp. and Bairdiella sp. were the most abundant and dominant, mainly during December. Structure and composition of the larval community were significantly different between areas (MW-U = 450; p < 0.05) and months of sampling (KW = 14.24; p < 0.05), with higher records in the exterior estuary during December. With the redundancy analysis (ADR) it is observed that in the exterior area, the species were associated with the transparency of the water, while the species that concurred in the interior zone were positively related to salinity. In general terms, the abundance and richness of fish larvae in the external area of the Gulf of Guayaquil is related to the conditions of transparency and local salinity, which favored the larval presence.

Resumen Objetivo. Establecer el listado taxonómico de las larvas de peces presentes en Cabo Manglares asociadas al distrito nacional de manejo integrado (DNMI) Cabo Manglares, Bajo Mira y Frontera. Alcance. Promover el conocimiento taxonómico sobre las larvas de peces presentes en ambientes costeros del Pacífico colombiano. Metodología. Se realizaron campañas de muestreo oceanográfico durante diciembre de 2016 y marzo de 2017 en el DNMI Cabo Manglares, Bajo Mira y Fronteras siguiendo una malla de muestreo de 32 estaciones. En total fueron obtenidas 128 muestras de zooplancton utilizando una red bongo con malla de 300 µm y 500 µm, a partir de las cuales se separaron las larvas de peces y se identificaron con base en sus caracteres morfométricos. Principales resultados. Se capturaron y procesaron 4947 larvas de peces durante los dos periodos de estudio. Se identificaron 153 unidades taxonómicas morfológicas de larvas de peces, pertenecientes a 43 familias, siendo las más abundantes las larvas de Bregmaceros bathymaster, Benthosema panamense y Cetengraulis mysticetus. El 9,9 % de las larvas capturadas durante diciembre de 2016 fueron vitelinas, mientras que durante marzo del 2017 solo el 2,7 % fueron vitelinas. El 28,8 % de las especies identificadas fueron registradas en ambos periodos de muestreo, mientras que el 63 % solo fueron registradas durante diciembre de 2016 y el 43,6 % solo en marzo de 2017. Conclusiones. Se establece el primer listado taxonómico de larvas de peces asociado la zona de Cabo Manglares (DNMI Cabo Manglares, Bajo Mira y Fronteras), encontrando evidencias que sugieren que la estructura del ensamblaje de larvas de peces en esta localidad exhibe una variación en escala estacional.

Abstract Objective. To establish the taxonomic list of fish larvae from Cabo Manglares, associated with the National Integrated Management District (DNMI) Cabo Manglares, Bajo Mira and Frontera. Scope. Promote taxonomic knowledge about fish larvae present in coastal environments of the Colombian Pacific. Methodology. Oceanographic sampling campaigns were carried out during December 2016 and March 2017 at the DNMI Cabo Manglares, Bajo Mira y Fronteras following a sampling grid of 32 stations. In total, 128 samples of zooplankton were obtained using a bongo net with 300 µm and 500 µm mesh, from which the fish larvae were separated and identified based on their morphometric characters. Main Results. 4947 fish larvae were captured and processed during the two study periods. 153 morphological taxonomic units of fish larvae, belonging to 43 families, were identified, the most abundant being the Bregmaceros bathymaster, Benthosema panamensis and Cetengraulis mysticetus larvae. 9.9% of the larvae captured during December 2016 were vitelline, while during March 2017 only 2.7% were vitelline. 28.8% of the identified species were recorded in both sampling periods, while 63.0% were only registered during December 2016 and 43.6% were only registered in March 2017. Conclusions. The first taxonomic list of fish larvae from Cabo Manglares and DNMI Cabo Manglares, Bajo Mira y Fronteras area was established, finding evidence that suggests that the structure of fish larvae assembly in this locality exhibits a variation in a seasonal scale.

Resumo: Os estudos sobre ecologia do ictioplâncton tornam-se essenciais quando se percebe a importância e influência deste componente na dinâmica, na conservação e na manutenção dos recursos pesqueiros. Porém, informações ecológicas desta natureza ainda são escassas e não têm sido devidamente valorizadas e utilizadas por gestores ambientais e tomadores de decisão. Neste ensaio apresentamos o estado da arte das pesquisas ictioplanctônicas na região Amazônica.O número de estudos vem aumentando com o decorrer do tempo, mas ainda são insuficientes e poucos abrangentes. Espera-se que esse trabalho sirva para valorizar o conhecimento e incentivar os estudos e pesquisas relacionadas ao ictioplâncton na região amazônica.

Abstract: Studies on ichthyoplankton ecology become essential when one realizes the importance and influence of this component in dynamics, conservation, and maintenance of fishery resources. However, ecological information about this subject is still scarce and has not been properly valued and used by environmental managers and decision-makers. In this study, we present the state of the art of research on ichthyoplankton in the Amazon region. The number of studies has been increasing over time but they are scarce and restricted. We hope this study may encourage research related to ichthyoplankton in the Amazon region.

Resumo: Objetivo Este estudo fornece a primeira evidência direta sobre a localização de um sítio de desova de Brycon orbignyanus (Valenciennes, 1850) no médio rio Uruguai. Métodos As amostragens foram realizadas com uma rede de plâncton (500 µm) durante novembro de 2017 no rio Uruguai, próximo a confluência com o rio Piratinim, RS, Brasil. A triagem foi realizada em campo e a identificação da espécie foi feita utilizando a técnica do ictioplâncton vivo. Resultados Foram capturados 47 ovos de B. orbignyanus na calha principal do rio Uruguai, em um trecho caracterizado por fluxo rápido, baixa profundidade (3 m) e fundo rochoso, localizado alguns quilómetros acima da confluência com o rio Piratinim. Os ovos são esféricos, bem hidratados, semi-densos, transparentes e não-adesivos, com uma única membrana e grande espaço perivitelino. O diâmetro total variou entre 3.500 e 4.000 µm. Os ovos estavam em estágio inicial de desenvolvimento embrionário e as células apresentavam 8, 16 ou 32 blastômeros. Um total de 16 ovos se desenvolveram em larva nos recipientes. As larvas eclodiram aproximadamente após 18 horas de incubação, e levaram 14 dias para virar juvenis. Conclusão Esse parece ser o primeiro registro de evidência de um local de desova de B. orbignyanus na Bacia do Rio da Prata, e indicam a relevância do médio rio Uruguai como área de recrutamento para essa espécie ameaçada.

Abstract: Aim This study provides the first direct evidence about the location of a spawning site of Brycon orbignyanus (Valenciennes, 1850) in the Middle Uruguay River. Methods Sampling was carried out with a plankton net (500 µm) in November 2017 in the Uruguay River near the confluence with the Piratinim River, southern Brazil. Eggs were sorted in the field, and to confirm species identity we used the live ichthyoplankton technique. Results We captured 47 eggs of B. orbignyanus in the channel of the Uruguay River, characterized by fast flow, shallow depth (approximately 3 m) and rocky bottom, located a few kilometers upstream from its confluence with the Piratinim River. Eggs are spherical, well hydrated, semi-dense, transparent and non-adhesive, with a single membrane and large perivitelline space. Total diameter varied between 3,500 and 4,000 µm. Eggs were in early stages of embryonic development, and cells showed 8, 16 or 32 blastomeres. A total of 16 eggs hatched into larvae in the plastic bags. Larvae hatched approximately 18 hours after incubation, and took 14 days to become juvenile. Conclusion This seems to be the first record of a spawning site of B. orbignyanus in the La Plata River Basin, and points to the relevance of the Middle Uruguay River as a recruitment area for this endangered species.

Abstract The influence of salinity and temperature on larval fish assemblages, as well as, temporal and vertical patterns on larval fish assemblages off the inlet of the Presidio River, southeast coast of the Gulf of California were evaluated. Samplings for ichthyoplankton and environmental parameter measurements were carried out at three depths, in five sampling sites, during September and December 1994, and April and June 1995. Anchovies and herrings (Clupeiformes) were the most abundant larval fish accounting for 77% of the total abundance. A significant relationship between salinity and the abundance of larval herrings (Opisthonema medirastre and O. dovii) and between the water temperature and the abundance of the weakfish (Cynoscion reticulatus) was found. Anchovies (Anchoa lucida, A. walkeri, and A. nasus) were present in all sampled months, while O. medirastre and O. dovii occurred in December and June, and C. reticulatus in September. Larvae of pelagic fish were more abundant near the surface, while larvae of demersal fish were more abundant near the bottom. The present study, by emphasising the importance of considering temporal and vertical changes in larval fish assemblages in coastal environments with ecological and economic importance, will be useful for designing more efficient sampling programs.

Resumen Se evaluó la influencia de la salinidad y la temperatura, así como patrones temporales y verticales en la comunidad de larvas de peces enfrente del río Presidio, costa sudeste del Golfo de California. Los muestreos de ictioplancton y las mediciones de los parámetros ambientales fueron realizados a tres profundidades, en cinco sitios de muestreo, durante septiembre y diciembre de 1994, y abril y junio de 1995. Las anchoas y sardinas (Clupeiformes) fueron las larvas de peces más abundantes representando el 77% de la abundancia total. Se encontró una relación significativa entre la salinidad y la abundancia de larvas de sardinas (Opisthonema medirastre and O. dovii), y entre la temperatura del agua y la abundancia de la corvina rayada (Cynoscion reticulatus). Las anchoas (Anchoa lucida, A. walkeri y A. nasus) estuvieron presentes en todos los meses muestreados, mientras que O. medirastre y O. dovii ocurrieron en diciembre y junio, y C. reticulatus en septiembre. Las larvas de peces pelágicos fueron más abundantes cerca de la superficie, mientras que las larvas de peces demersales fueron más abundantes cerca del fondo. El presente estudio, al enfatizar la importancia de considerar los cambios temporales y verticales en el ensamblaje de larvas de peces en ambientes costeros con importancia ecológica y económica, será útil para diseñar programas de muestreo más eficientes.