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In South America, knowledge of major spawning sites is crucial for maintaining migratory fish populations. In this study, we aimed to understand the spatio-temporal distribution of fish eggs in the upper São Francisco River using high sampling frequency and DNA metabarcoding identification. We evaluated the possible effects of the non-molecular identification of eggs and decreased sampling frequency on the determination of spawning sites and major breeding periods. Collections were carried out every three days from November 2019 to February 2020. We found that, if we had assumed that all of the free and non-adhesive sampled eggs belonged to migratory species, as is usual in the literature, this assumption would have been wrong for both the spawning sites and the breeding periods. Moreover, any decrease in the frequency of sampling could dramatically affect the determination of the major spawning rivers, and the spawning events of some of the migratory species may not have been detected. Therefore, without the proper identification and adequate sampling frequency of eggs, important spawning sites may be overlooked, leading to ineffective or inappropriate conservation measures. [ABSTRACT FROM AUTHOR]

The species structure and spatial distribution of ichthyoplankton in July–August 2019 during the period of mass spawning of warm-water fish species are presented. The material was collected at the shelf and in the deep waters of the Black Sea off the Crimean Peninsula and along the Caucasian coast. In ichthyoplankton, eggs and larvae of 29 species of fish from 19 families were identified. The indices of species richness in the open sea and in the coastal areas were similar. European anchovy Engraulis encrasicolus (Linnaeus, 1758) dominated in ichthyoplankton, its maximum egg abundance reached 260 ind./m2, larvae abundance, 117 ind./m2. The highest spawning efficiency of E. encrasicolus was observed in coastal waters heated up to 26–27°C near the Caucasian coast and on the western shelf of the Crimean Peninsula, where the ratio of the number of larvae to the number of eggs was 30% in the samples. An increased population density of ichthyoplankton was also noted within the Crimean anticyclonic gyre, the shelf thermodynamic formation most stable in time. We assume that favorable conditions were formed there for spawning and survival of fish at the early stages of development. [ABSTRACT FROM AUTHOR]

Fish larval drift is an essential step in the life cycle of riverine fish species as it determines dispersal and colonisation. Anthropogenic flow alterations and interruption of longitudinal and lateral connectivity by river damming and straightening can severely affect larval drift patterns. In this study, we characterised spatio‐temporal drift patterns of fish larvae in the heavily regulated large alpine River Inn and within a constructed nature‐like fish bypass.Drift was investigated in the main reproduction period of the fish fauna in this river, ranging from mid‐April to end of June. Diel patterns were assessed by samples taken during day, dusk, night, and dawn each day of sampling. To obtain robust species identification, we used DNA barcoding for genetic verification of phenotypically pre‐sorted groups.From a total of 1,069 fish larvae and 283 fish eggs caught, DNA barcoding revealed 16 species from five families, including several target species of conservation. We found strong evidence that several endangered species, such as Chondrostoma nasus, Thymallus thymallus, Cottus gobio, and Aspius aspius successfully reproduced in the bypass system. Genetic species verification showed a high level of homogeneity in most phenotypically pre‐sorted groups.Distinct seasonal patterns were observed, with the majority of fish species in the drift observed in mid‐June. Thymallus thymallus and Cottus gobio dominated larval drift at the beginning of the observation followed by mainly unimodal abundance peaks of several Cyprinid species. Nocturnal drift prevailed in all species.Our results on the spatial occurrence and abundances of fish larvae highlight the importance of bypass systems in heavily modified waterbodies to provide valuable spawning habitats and drift corridors around dams. Moreover, the distinct species‐specific time patterns of larval drift represent a first basis to direct future discharge and river management plans in large alpine rivers towards a protection of the sensitive larval stages of specific target species of conservation. This includes bypass and turbine operation modes in the period of highest drift activity, as well as the construction of nature‐like bypass systems and creation of spawning grounds therein. [ABSTRACT FROM AUTHOR]

The research focuses mainly on the ichthyoplankton of the Baltic deeps – the inflow route from the North Sea. The ichthyoplankton was represented by eggs and larvae of nine fish species: sprat, cod, herring, European flounder, fourbeard rockling, longspined bullhead, straightnose pipefish, sand goby and great sandeel. The species composition of ichthyoplankton varied depending on the location of a given site – the number of taxa ranged from one to five. The Slupsk Furrow was the most diversified area in terms of the number of taxa, while the highest abundance of ichthyoplankton occurred in the Bornholm Basin. The sprat clearly dominated and inhabited all the surveyed depths. Of the remaining species, only cod eggs as well as eggs and larvae of the fourbeard rockling significantly contributed to this formation. They occurred within their main spawning grounds (Bornholm Deep in the near-bottom layers) and secondary spawning grounds (Slupsk Furrow and Gdansk Deep) where salinity and oxygenation of water favored their development. Biometric research has shown that the diameter of eggs was within the size range typical of the Baltic Sea. [ABSTRACT FROM AUTHOR]

The eco-hydraulic diversity in a tidal reach is obviously enriched after spur dikes built, such as a turbulent rapid around structures head when tide ebbing and a gently dynamic environment in the back during the whole tide process. It would be much beneficial for adult fishes to spawn eggs and the youngs to fatten. Spur dikes have been utilized as channel regulation structures worldwide, especially in the upstream tidal reach of river estuary, where is a superexcellent habitat for resident fish or migratory fish during different life history stages. However, local hydraulic characters will be altered upon spur dikes establishment, resulting in several influence on fish habitat. The purpose of this paper was to reveal the impacts mechanism of spur dikes on fish habitat in a tidal reach through a comprehensive analysis based on some previous neglected aspects, such as fish physiological characters, hydraulic variations and essential factors alterations of the aquatic ecosystem. Hydraulic information around spur dikes was acquired through a 3D hydrodynamic model, and validations of tidal level, velocity and diversion ratio yielded a high accuracy. Turbulent rapid around spur dikes head and mild nearshore environment behind structures have some potentialities to become new spawning grounds, for fish spawning semi-pelagic eggs and fish laying adhesive eggs respectively. Benefitted from effective mixture of water during a tidal cycle, plenty of planktons and organic matters will be brought in and gradually enriched behind structures, thus a favorable feeding ground will appear there. Meanwhile, deflecting flow induced by spur dikes may cause some hazards for survival probability of migratory larval fish. It is drifted off the nearshore into the river middle, where is a higher turbulent intensity and less phytoplankton concentration. In summary, spur dikes possess tremendous ecological effects, i.e. enriching the eco-hydraulic diversity, not only as a velocity shelter. In addition, research result could afford a sufficient basis for environment conservations to restore aquatic ecosystem with spur dikes. [ABSTRACT FROM AUTHOR]

The Neotropical fish fauna comprises approximately 6080 species, of which almost 3000 inhabit the Amazon River basin. However, the construction of hydroelectric dams has threatened this biodiversity by habitat fragmentation. To uncover the putative effect of river impoundment on migratory fish species, over 5400 eggs and larvae were collected from the Teles Pires River, including five tributaries and the hydroelectric reservoir, which were identified using the COI metabarcoding approach. Identification of early life stages allowed the detection of >40 fish species, including at least 27 migratory species. Fish eggs were assigned to nine families, 13 genera, and 23 species, whereas larvae were attributed to 12 families, 18 genera, and 34 species. Eggs and larvae of migratory fishes were primarily present in tributaries upstream of the dam, with fewer in the reservoir. A putative impact of the dam on the ichthyoplankton community was detected, with a significant difference found between the reservoir and tributaries for larval species richness (r = 0.822, p = 0.0211). In contrast, no significant difference was recovered among tributaries for both eggs (r = 0.213, p = 0.2657) and larvae (r = 0.378, p = 0.0696). However, a change in ichthyoplankton assemblage was observed between tributaries, as revealed by beta diversity analyses. These results highlight the potential of ichthyoplankton metabarcoding for studying and biomonitoring of migratory fishes, as well as providing relevant data concerning the identification of spawning sites to set guidelines for fisheries management and effective conservation of fish populations. [Display omitted] • Hydroelectric power plant dams block migratory routes for fish spawning. • Metabarcoding is a powerful method to identify ichthyoplankton and spawning areas. • Amazonian tributaries are used as spawning areas for several migratory fish species. • Fewer migratory fish spawn at sites near the river impoundments. • Ichthyoplankton identification should consider metabarcoding as a prime approach. [ABSTRACT FROM AUTHOR]

The East China Sea (ECS) is one of the most important fish spawning and nursery grounds in the north Pacific. Even though summer is an important spawning season for many fishes in the region, large-scale molecular identification studies on ichthyoplankton during this season are few. In this study, we sampled 8,933 fish eggs and 12,161 fish larvae from 25 stations during the summer of 2009. Using DNA barcoding, a number of the fish eggs and larvae were identified and classified into 45 and 124 taxa, respectively. Principal component analysis (PCA) categorized the inshore stations of the Changjiang Diluted Water area as having the hydrographic features of low sea surface temperature (SST), salinity (SSS) and high chlorophyll a (SSC) contents, whereas the continental shelf and offshore stations under the influence of the Kuroshio Current displayed the opposite results. Ichthyoplankton was more abundant at the inshore stations than the offshore stations, but species diversity was lower at the former locations. Species compositions of both fish eggs and fish larvae at the 25 stations were categorized into three different assemblages based on a non-metric multidimensional scaling analysis. Combining the assemblage patterns of ichthyoplankton with the results of the PCA and satellite images of SST and SSC showed that the assemblage patterns of fish eggs were correlated with water mass, while those of the fish larvae were not. [ABSTRACT FROM AUTHOR]

Broodstock of Atlantic cod were fed with three diets; astaxanthin supplemented (100 ppm kg−1) hydrated diet (30% water) ( HWHAs), no additional astaxanthin supplemented (50 ppm kg−1) hydrated diet (30% water) ( HWLAs) and a control diet (50 ppm kg−1 astaxanthin and 10% water). Throughout the spawning period, eggs were collected daily and fertilization success and proportion of embryos with normal cleavage were recorded. Larvae were reared using standard culture methods. Larval growth was recorded every 10 days and larval survival was recorded at 50 days post hatch. In general, broodstock fed with diets containing higher water content ( HWHAs and HWLAs) and higher astaxanthin ( HWHAs) had higher egg production and efficiency of egg output, lower egg incubation mortality and higher larval growth and survival. Broodstock fed with higher water content diets consumed less feed compared to control group. Also, broodstock fed with HWHAs and HWLAs recovered faster in terms of body condition than the control group. The egg bound mortality of female fish was significantly higher in control broodstock compared to broodstock fed with HWHAs and HWLAs. Broodstock fed with higher astaxanthin ( HWHAs) had significantly higher fertilization success than other two groups however; no differences were found in proportion embryos with normal cleavage among different groups. Larval survival was significantly higher in HWHAs broodstock compared to other two groups. Our results showed that increased water content and astaxanthin levels in the diet could improve the condition and fecundity of Atlantic cod broodstock. [ABSTRACT FROM AUTHOR]

The aim of the present study is to investigate the influence of oceanic features on the distribution and abundance of bluntnose flyingfish ( Prognichthys occidentalis) larvae in the northern Gulf of Mexico (NGoM). Summer ichthyoplankton cruises were conducted from 2009 to 2011 using a neuston net towed through the upper meter of the water column. Interannual variation was detected with densities of bluntnose flyingfish larvae higher in 2009 and 2010 than 2011. Bluntnose flyingfish larvae were present in each month and year sampled, suggesting that this species is a common and important component of the ichthyoplankton assemblage in this region. Generalized additive models were used to evaluate the effect of oceanographic conditions on the abundance of bluntnose flyingfish, and several environmental variables (sea surface height anomaly, distance to Loop Current, and salinity) were found to be influential in explaining patterns of abundance. Habitat suitability was linked to physicochemical properties of the seawater, and higher larval abundances were found at higher salinities and negative sea surface heights. This study emphasizes the importance of NGoM as a spawning/nursery area of bluntnose flyingfish and suggests that oceanographic conditions play an important role in determining the distribution and abundance of bluntnose flyingfish. [ABSTRACT FROM AUTHOR]

This study deals with the evaluation of egg and larval qualities for the Northern pike Esox lucius Linnaeus, 1758 according to two dates during a spawning season, on March 16 (ST1) and 23 (ST2). A higher hatching rate (97% for ST1 vs 80% for ST2) associated to a stronger resistance to starvation (21.0 days for ST1 vs 19.1 days for ST2) and a better survival rate (72% for ST1 vs 59% for ST2) were found to characterize larvae hatched from eggs spawned earlier. Moreover, a significant female effect was observed for the egg weight, the fertilization rate, the initial total length, the final weight and the resistance to starvation, where some homogeneities were found between eggs and offspring of different females from the two spawning times. Our results suggest the existence of an early organization of pike larval quality, which gives rise to two groups of larvae with different characteristics. Late season individuals were of a large size and a fast growth while early season ones were smaller but survived longer and resisted better to unsuitable feeding conditions. This particularity is likely to be related to a special metabolic ability allowing pike larvae hatched earlier on the spring season to decrease energetic costs in order to survive longer in the absence of adequate food. [ABSTRACT FROM AUTHOR]

We developed a realistic 1/50° high-resolution ocean model capable of resolving submesoscale variability, and performed particle-tracking experiments based on this ocean model to identify elements that significantly affect the transport of the eggs and larvae of the Japanese Pacific walleye pollock Theragra chalcogramma into Funka Bay. The high-resolution model reproduced representative features of the oceanographic conditions of the main spawning area and season. A comparison of particle-tracking experiments performed under the passive transport condition based on high-resolution (1/50°) and low-resolution (1/10°) ocean models showed that high-resolution modeling is essential in order to realistically simulate the transport process. In this regard, however, the vertical motion of particles cannot be explained by the passive transport condition, as it leads to unrealistically deep sinking of particles in the simulation. Turning our attention to feasible non-passive transport conditions, we then incorporated the buoyancy motion of particles and conducted additional experiments that mainly differed in the particle density adopted. We clarified that buoyancy is an important factor in the retention of particles near the sea surface, and that the ratio of the particles that remain in Funka Bay to the number of particles released is sensitive to the vertical motions/positions of the particles, implying that it is necessary to model this vertical motion more accurately by incorporating more realistic biological processes or a statistical distribution into the particle-tracking model. [ABSTRACT FROM AUTHOR]

Abstract: Previous studies have demonstrated that oil sands process-affected water (OSPW) impairs the reproduction of fish and that naphthenic acids (NAs), a natural constituent of oil sands, are suspected of being responsible. This study evaluates the potential impact of NAs on the reproduction of adult fathead minnows (Pimephales promelas) under laboratory conditions. Fathead minnows exposed to a 10mg/l naphthenic acid extract (NAE) for 21 days spawned fewer eggs and males had reduced expression of secondary sexual characteristics. Male fathead minnows exposed to a 5mg/l NAE had lower plasma levels of 11-ketotestosterone whereas those exposed to a 10mg/l NAE had lower concentrations of both testosterone and 11-ketotestosterone. Since OSPW also contains high concentrations of salts, this study also investigated whether they modify the toxicity of NAEs. Spawning was significantly reduced in fathead minnows exposed to a 10mg/l NAE alone and in combination with NaHCO3 (700mg/l), typical of concentrations in OSPW. Interestingly, the addition of NaHCO3 reduced the inhibitory effects of the NAE on the numbers of reproductive tubercles and plasma testosterone levels. Further studies showed that NaHCO3 acted by reducing the uptake of the NAE to the fish. NaHCO3 but not NaCl or Na2SO4 reduced the acute toxic effects of the NAE on fathead minnow embryo and larvae mortality. Collectively, these studies show that the NAs in OSPW have the potential to negatively affect reproduction in fathead minnows and that HCO3 − reduces the acute and chronic toxicity of NAs. [Copyright &y& Elsevier]

Abstract: Induced spawning of common snook, Centropomus undecimalis (Bloch, 1792) and scale-up of larval rearing is described. Fertilized eggs were obtained from sGnRHa induced broodstock, acclimatized to captivity under natural conditions, for 5years in 12-m3 fiberglass tanks. Females with 402±15μm diameter vitellogenic oocytes were given an implant dose of 121±31μgkg−1 while males received 83±6μgkg−1. A total of 4.33×106 eggs (18.5% floating) resulted from ten natural voluntary spawns. Two 5-m3 cylindrical fiberglass tanks were stocked at an average of 40floating eggsl−1, which resulted in 14larvael−1 at 2days post hatch (dph). A total of 70,936 juveniles were harvested on 45dph (50.7% survival from first feeding). Two critical periods occurred, between 1 and 2dph, and during transformation (20–23dph). Final mean total length and weight at 46dph were 21.26±2.83mm (0.42mmday−1) and 0.07±0.03g (0.002gday−1). Mean final density and biomass were 7.1juvenilesl−1 and 0.479kgm−3. The incidence of deformities was low, less than 2%, mostly lordosis. Improvements for spawning common snook including changes in feeding regime and GnRHa implant doses are detailed along with suggestions for further improvements in mass production technology. [Copyright &y& Elsevier]

We investigate the effect of strong meteorological perturbations in early spring on the success of mackerel ( Scomber scombrus) recruitment in the N/NW Iberian area (southern Bay of Biscay) for the period 1999-2008. In 2000, the year of the most pronounced recruitment failure on record, two consecutive multidisciplinary surveys sampled hydrographic conditions and mackerel eggs, larvae and post-larvae over the main mackerel spawning grounds of the north and northwest coast of the Iberian Peninsula. Analysis of egg and larval abundance and birthdates based on the otoliths of mackerel juveniles caught between July and October 2000 showed that there were no survivors from the early spring spawns, indicating a massive loss of early spawning effort. Moreover, the abundance of 1-year-old mackerel estimated from an acoustic survey carried out in 2001 was the lowest observed within the 1999-2008 time series. This low or null survival from the early spawns in 2000 could be due to the meteorological and oceanographic conditions of that spring, in particular two storm events in April after a relatively calm March. The first storm event from the north caused strong local wind in the southern Bay of Biscay but a weak oceanographic response. The second storm event from the southwest was mainly felt west of Galicia and caused a notable increase in shelf currents and a shift of the hydrographical structure along the shelf. Detailed analysis of strong wind pulses in early spring within the historical recruitment record suggests that strong local turbulence generated by high wind speeds and advection of larvae caused by the enhancement of shelf currents can contribute to reduced recruitment. Our observations indicate that, in 2000, both mechanisms were present. [ABSTRACT FROM AUTHOR]

Abstract: Knowledge of early life history of most fish species in the Mediterranean Sea is sparse and processes affecting their recruitment are poorly understood. This is particularly true for bluefin tuna, Thunnus thynnus, even though this species is one of the world’s most valued fish species. Here we develop, apply and validate an individually based coupled biological–physical oceanographic model of fish early life history in the Mediterranean Sea. We first validate the general structure of the coupled model with a 12-day Lagrangian drift study of anchovy (Engraulis encrasicolus) larvae in the Catalan Sea. The model reproduced the drift and growth of anchovy larvae as they drifted along the Catalan coast and yielded similar patterns as those observed in the field. We then applied the model to investigate transport and retention processes affecting the spatial distribution of bluefin tuna eggs and larvae during 1999–2003, and we compared modelled distributions with available field data collected in 2001 and 2003. Modelled and field distributions generally coincided and were patchy at mesoscales (10s–100skm); larvae were most abundant in eddies and along frontal zones. We also identified probable locations of spawning bluefin tuna using hydrographic backtracking procedures; these locations were situated in a major salinity frontal zone and coincided with distributions of an electronically tagged bluefin tuna and commercial bluefin tuna fishing vessels. Moreover, we hypothesized that mesoscale processes are responsible for the aggregation and dispersion mechanisms in the area and showed that these processes were significantly correlated to atmospheric forcing processes over the NW Mediterranean Sea. Interannual variations in average summer air temperature can reduce the intensity of ocean mesoscale processes in the Balearic area and thus potentially affect bluefin tuna larvae. These modelling approaches can increase understanding of bluefin tuna recruitment processes and eventually contribute to management of bluefin tuna fisheries. [Copyright &y& Elsevier]

Fishery independent indices of spawning biomass of Atlantic bluefin tuna in western North Atlantic Ocean are presented which utilize National Marine Fisheries Service ichthyoplankton survey data collected from 1977 through 2007 in the Gulf ofMexico. Indices were developed using similarly standardized data from which previous indices were developed (i.e. abundance of larvae with a first daily otolith increment formed per 100 m2 of water sampled with bongo gear). Indices were also developed for the first time from standardized data collected with neuston gear [i.e. abundance of 5-mm larvae (i.e. seven-day-old larvae) per 10 minute tow]. Indices of larval abundance were developed using delta-lognormal models, including following covariates: time of day, time of month, area sampled and year. Due to the large frequency of zero catches during ichthyoplankton surveys, a zero-inflated delta-lognormal approach was also used to develop indices. Finally, a multivariate delta-lognormal approach was employed to develop indices of annual abundance based on both bongo and neuston catches. The results of these approaches were compared with one another and with other indices of larval abundance previously developed for the Gulf of Mexico. Residual analyses indicated that abundance indices of Atlantic bluefin tuna larvae were more appropriately developed from bongo-collected data through the zero-inflated delta-lognormal approach than other data sets and modeling approaches. Also, when modeling bongocollected data with the zero-inflated delta-lognormal approach, the index values increased, indicating some correction for zero-inflation, and their variability decreased as compared to indices developed with the delta-lognormal approach. [ABSTRACT FROM AUTHOR]

Folkvord, A., Høie, H., Johannessen, A., and Solbakken, T. 2009. Effects of prey concentration, light regime, and parental origin on growth and survival of herring larvae under controlled experimental conditions. – ICES Journal of Marine Science, 66: 1702–1709. Experiments were undertaken to study the combined effects of environmental (prey concentration and photoperiod) and genetic (parental spawning season) factors on growth and survival of herring larvae. During the experimental period, constant prey concentrations were maintained at one of the two nominal levels, under either a spring or an autumn light regime. Eggs of one autumn-spawning North Sea Buchan female herring were fertilized either with cryopreserved sperm from three Norwegian spring-spawning males or with fresh sperm from three Buchan males. Larvae of the two groups (the hybrids marked with alizarin) were mixed in replicated treatment tanks, thus ensuring identical environmental conditions. Mean larval growth rates were mostly influenced by food availability, but the hybrids grew significantly faster than the pure autumn-spawned offspring. In addition, the hybrids experienced a survival advantage at low prey concentrations. Hybrid survival was also somewhat better at high prey concentrations under a spring photoperiod than the corresponding group under an autumn photoperiod, suggesting a possible genetic adaptation to seasonal light conditions. The experiment documents the viability beyond first-feeding of offspring from parents with different spawning periods. The results are discussed in relation to herring metapopulation structure. [ABSTRACT FROM PUBLISHER]

Abstract: The egg and larval quality of red porgy (Pagrus pagrus) during six consecutive spawning seasons was analyzed. The spawning season of red porgy in captivity lasted between 2 and 4 months, showing wide daily variations in relative fecundity and floating rate. Annual fecundity showed a minimum of 331,900 eggs kg−1 in 2003 and a peak of 958,200 eggs kg−1 female wet weight in 2002. Floating rate differed significantly among seasons, with an average gross value of 52.7%. Annual profuction of floating eggs ranged between 131,500 eggs kg−1 (2003) and 646,300 eggs kg−1 female wet weight (2002), representing a 39.6% and a 67.4% of the annual fecundity, respectively. A multiple regression model using hatching and floating rates was formulated, which correlated well with larval survival as dependent variable. Our results indicated that hatching and floating rates could be used as potential markers to predict survival of red porgy larvae with certain degree of accuracy very early during hatchery activities. [Copyright &y& Elsevier]

Oceanic tropical waters are characteristically oligotrophic. However, current-topography interaction around oceanic islands promotes bio-physical processes, which may enrich surface waters. The ichthyoneuston assemblage at three areas around oceanic islands in the tropical Atlantic was investigated. The aim was to evaluate if the ichthyoneuston was influenced by physical oceanographic processes, such as possible mechanisms of plankton retention promoted by the presence of the islands. Samplings were performed by 20 min long diurnal and nocturnal 500-μm plankton net hauls using a David-Hempel Catamaran at two transections in each area (Saint Peter and Saint Paul's archipelago, Fernando de Noronha archipelago, and Rocas Atoll). The transections were composed by three stations and were located at opposite sides of the archipelagos (windward and leeward sides of the archipelago). A total of 131 larvae and 3027 eggs, belonging to 16 families and 28 species were collected. Higher densities of eggs were found at the leeward side, which indicates the occurrence of a retention mechanism or spawning at this side. Higher densities of larvae were found at Fernando de Noronha, especially during the nocturnal period. Only one species, Ceratoscopelus warmingii , co-occurred at the three islands. Fernando de Noronha was highlighted as the area with the higher density, abundance and species richness. The waters around this island were positively correlated with chlorophyll- a , which indicates a higher availability of food items and stimulates the selection of this area as a favorable spot for reproduction and early nursery zone. This work highlighted the importance of the relation between abiotic factors and the distribution of fish eggs and larvae inhabiting the neustonic layer around South Atlantic oceanic islands, showing that favorable conditions, e.g. higher phytoplanktonic biomass, may be of fundamental importance to the spawning by adult individuals. • Fish eggs and larvae within the neustonic layer were investigated around three island systems of the tropical South Atlantic • A possible fish eggs retention mechanism was indicated by different concentrations at opposite sides of the archipelagos • Availability of food items was highlighted as an important factor influencing spawning of fishes • The importance of the relation among abiotic factors and the ichthyoneustonic distribution was highlighted [ABSTRACT FROM AUTHOR]