Os peixes da família Myctophidae constituem do ponto de vista ecológico o grupo mais importante da fauna mesopelágica, tanto em número de espécies, quanto em biomassa. Fazem parte da dieta de uma grande variedade de cetáceos e peixes oceânicos. Representam também uma considerável fonte de proteína animal, ainda não diretamente explorada. Além disso, estes peixes tem papel importante na transferência de energia das camadas superficiais oceânicas para as mais profundas através de um comportamento migratório vertical diário de centenas de metros característico. O material deste estudo provém de um Programa de Avaliação do Potencial Sustentável de Recursos Vivos na Zona Econômica Exclusiva (Programa Revizee), no qual foram efetuados arrastos com rede de meia água com o N/Oc. Atlântico Sul, entre as isóbatas de 100 e 1500 m, de 22oS a 35oS, realizados no inverno de 1996, outono e primavera de 1997, e outono e primavera de 1999. As características morfológicas descritivas das 37 espécies coletadas foram analisadas e comparadas com dados morfológicos de exemplares coletados de outras regiões do Atlântico, constantes da literatura. A análise destas comparações mostrou que 17 das espécies apresentaram pelo menos uma diferença morfológica consistente nos caracteres estudados, sugerindo isolamento e diferenciação na área pesquisada. Além disso, informações sobre a distribuição geográfica destas espécies no Atlântico são apresentadas e discutidas frente aos padrões biogeográficos estabelecidos pelos pesquisadores para organismos mesopelágicos do Atlântico. Fica evidente que apesar da contribuição que este trabalho trouxe em relação ao conhecimento destes peixes nesta região, o número de amostras analisadas até hoje no Atlântico Sul ainda é pequeno para que o conhecimento taxonômico e de distribuição dos Myctophidae torne-se conclusivo. / From an ecological point of view the Myctophidae fishes constitute the most important group of the mesopelagic fauna, considering as much as number of species, as biomass. They are part of the diet of a great variety of cetaceans and marine fishes. They also represent a remarkable animal protein source, although not directly exploited. Besides these fishes have important role at energy transference from the upper productive zones to deeper, trophically poorer, through a daily vertical migratory behavior of hundreds of meters. The material of this study results from a Program of Evaluation of the Sustainable Potential of the Livings Resources in the Exclusive Economic Zone (Revizee Program), in which sampling was done using mid water trawl on board R/V Atlântico Sul, between 100 and 1500 meters deep, latitudes between 20oS and 30oS, during winter of 1996, autumn and spring of 1997, and autumn and spring of 1999. The descriptive morphological characteristics of the 37 collected species were analyzed and compared to the morphological data of specimes collected from other regions of Atlantic Ocean, according to the literature. The analysis of these comparisons showed that 17 of the species presented at least one consistent morphological difference in the studied characters, suggesting isolation and differentiation in the studied area. Moreover, information concerning geographical distribution of these species at the Atlantic Ocean are presented and argued front to the biogeographics patterns established by researchers of the mesopelagical ichthyofauna of the referred ocean. It is evident that despite the contribution of the present study to the knowledge of these fishes in this region, the quantity of samples analyzed until now in the South Atlantic Ocean is still small so that the taxonomic knowledge and distribution of the Myctophidae becomes conclusive.

Os peixes da família Myctophidae constituem do ponto de vista ecológico o grupo mais importante da fauna mesopelágica, tanto em número de espécies, quanto em biomassa. Fazem parte da dieta de uma grande variedade de cetáceos e peixes oceânicos. Representam também uma considerável fonte de proteína animal, ainda não diretamente explorada. Além disso, estes peixes tem papel importante na transferência de energia das camadas superficiais oceânicas para as mais profundas através de um comportamento migratório vertical diário de centenas de metros característico. O material deste estudo provém de um Programa de Avaliação do Potencial Sustentável de Recursos Vivos na Zona Econômica Exclusiva (Programa Revizee), no qual foram efetuados arrastos com rede de meia água com o N/Oc. Atlântico Sul, entre as isóbatas de 100 e 1500 m, de 22oS a 35oS, realizados no inverno de 1996, outono e primavera de 1997, e outono e primavera de 1999. As características morfológicas descritivas das 37 espécies coletadas foram analisadas e comparadas com dados morfológicos de exemplares coletados de outras regiões do Atlântico, constantes da literatura. A análise destas comparações mostrou que 17 das espécies apresentaram pelo menos uma diferença morfológica consistente nos caracteres estudados, sugerindo isolamento e diferenciação na área pesquisada. Além disso, informações sobre a distribuição geográfica destas espécies no Atlântico são apresentadas e discutidas frente aos padrões biogeográficos estabelecidos pelos pesquisadores para organismos mesopelágicos do Atlântico. Fica evidente que apesar da contribuição que este trabalho trouxe em relação ao conhecimento destes peixes nesta região, o número de amostras analisadas até hoje no Atlântico Sul ainda é pequeno para que o conhecimento taxonômico e de distribuição dos Myctophidae torne-se conclusivo. / From an ecological point of view the Myctophidae fishes constitute the most important group of the mesopelagic fauna, considering as much as number of species, as biomass. They are part of the diet of a great variety of cetaceans and marine fishes. They also represent a remarkable animal protein source, although not directly exploited. Besides these fishes have important role at energy transference from the upper productive zones to deeper, trophically poorer, through a daily vertical migratory behavior of hundreds of meters. The material of this study results from a Program of Evaluation of the Sustainable Potential of the Livings Resources in the Exclusive Economic Zone (Revizee Program), in which sampling was done using mid water trawl on board R/V Atlântico Sul, between 100 and 1500 meters deep, latitudes between 20oS and 30oS, during winter of 1996, autumn and spring of 1997, and autumn and spring of 1999. The descriptive morphological characteristics of the 37 collected species were analyzed and compared to the morphological data of specimes collected from other regions of Atlantic Ocean, according to the literature. The analysis of these comparisons showed that 17 of the species presented at least one consistent morphological difference in the studied characters, suggesting isolation and differentiation in the studied area. Moreover, information concerning geographical distribution of these species at the Atlantic Ocean are presented and argued front to the biogeographics patterns established by researchers of the mesopelagical ichthyofauna of the referred ocean. It is evident that despite the contribution of the present study to the knowledge of these fishes in this region, the quantity of samples analyzed until now in the South Atlantic Ocean is still small so that the taxonomic knowledge and distribution of the Myctophidae becomes conclusive.

To clarify the spatiotemporal distribution of the winter and spring larval fish assemblage in the coastal waters off Kaohsiung and Pingtung, Taiwan, larval fishes were collected during four research cruises by conducting 35 tows of the larval net in coastal waters off Zuoying, Linyuan, Linban and Fangliao in January and March 2009 and in coastal waters off Linyuan adjacent to the Kaoping River estuary in January and March 2010. Water temperature, salinity and dissolved oxygen were measured during the sampling of the fish larvae. Seawater samples were also collected for analyzing concentrations of nutrient salts. In 2009, a total of 2,023 fish larvae, representing 38 families and 74 species, were collected. The fish larvae assemblage exhibited seasonal variation in both abundance and species composition. The abundance (460 ind./1000m3) and the number of species (34 families and 66 species) of the fish larvae collected in March were higher than those (28 ind./1000m3, 14 families and 27 species) collected in January. Fish larvae also exhibited spatial variation in species composition. In January, the most dominant families of fish larvae were: Myctophidae off Linyuan, Sparidae off Linban and Nomeidae off Fangliao. In March, in the northward coastal waters off Linyuan Scombridae was the most dominant family, and in the southward coastal waters off Linyuan, Clupeidae and Sillaginidae were the dominant families. No significant differences existed in the abundance of fish larvae among the sampling areas, but the abundance of fish larvae in the sampling sites off Linyuan and Linban tended to be strongly influenced by tide. In 2010, a total of 1,959 fish larvae, representing 39 families and 59 species, were collected. These fish larvae showed diurnal and seasonal variations in abundance and in species composition. The abundance (767 ind./1000m3) and the number of species (39 families and 55 species) of the fish larvae in March were higher compared with those (26 ind./1000m3, 16 families and 25 species) in January. Moreover, the abundance of fish larvae in the nighttime was higher than that in the daytime. In March, the most dominant family in the daytime was Serranidae, whereas the most dominant family in the nighttime was Myctophidae, indicating the diurnal migration of Myctophidae these larvae. Cluster analysis indicated that the abundance and species composition of the fish larvae differed between January and March in 2009. The difference in species composition among the four sampling areas was only found significant for the fish larvae collected in the coastal waters off Fangliao in winter, and the most influenced families were Nomeidae and Myctophidae. In 2010, seasonal variations were found in the abundance and species composition of the fish larvae, and the abundance of the fish larvae showed the difference between nearshore and inshore sampling sites in the nighttime in winter. In spring, the fish larvae were all inshore fishes, but the species composition had annual variation. The temperature and salinity data obtained in the sampling sites conformed to the surface seawater of South China Sea, indicating that the occurrence of the dominant family Scombridae may be related to the seawater of South China Sea.

The diel vertical migration (DVM) and feeding periodicity of myctophids (lanternfishes) were studied in the high-latitude Masfjorden, Norway, and the tropical Red Sea. In Masfjorden, a bottom-mounted echo sounder permitted continuous studies throughout the year, and revealed a diverse seasonal DVM behavior. During spring and summer, when zooplankton peaks in the epipelagic zone, migrating glacier lanternfish performed normal DVM (NDVM), ascending to the epipelagic zone during night and residing below ~200m during daytime. During autumn and winter, when Calanus overwinters between ~150–300 m, migrating glacier lanternfish mainly performed inverse DVM (IDVM), ascending to feed on Calanus in mid-waters during daytime. Non migrating (NoDVM) individuals were present all year below ~300 m in Masfjorden. In the Red Sea, where zooplankton has an epipelagic distribution, the whole population of skinnycheek lanternfish performed NDVM, feeding in the epipelagic zone at night, while residing at ~500–750 m during daytime. The warm waters of the Red Sea were hypothesized to limit the time individuals can stay in the mesopelagic zone without migrating to feed in the epipelagic layers. The DVM behavior of myctophids largely seemed to relate to the distribution of zooplankton, and it was hypothesized that NDVM will prevail with epipelagic distribution of prey, while IDVM and NoDVM are common in areas where zooplankton migrate seasonally to mesopelagic depths. Potential predators were continuously present, found to apparently attack glacier lanternfish, at mesopelagic depth in Masfjorden. Thus, myctophids are under threat of predation even at mesopelagic depth.