Larvae Of Fish Species Research Articles

Winter Time Ichthyoplankton Assemblages Following Dense Mucilage Event in the Sea Of Marmara, Türkiye

The community structure of ichthyoplankton after mucilage was investigated. For this purpose, three ichthyoplankton survey were conducted from 34 stations between December 2021 and March 2022. A total of 19 fish egg and 16 fish larvae species were identified. It was detected that the biodiversity of winter time ichthyoplankton was higher than previous studies. European Sprat, Sprattus sprattus had the highest mean biomass for both fish eggs and fish larvae, whereas Sardine, Sardina pilchardus had relatively low biomass. Karacabey Floodplain area, Büyükçekmece estuarine area and Erdek Bay were the most important spawning areas for winter spawners. It was found that ecosystem health of the Marmara Sea was suitable for fertilization, hatching and larval growth soon after the mucilage and hydrological regime recover itself immidiatelly.

БАЛЫҚ ДЕРНӘСІЛДЕРІН ӨСІРУ ҮШІН ОҢТАЙЛЫ ҚОРЕК РЕСУРСЫ РЕТІНДЕ АРТЕМИЯЛАРДЫ ӨНДІРУ

In aquaculture, the use of Artemia as an optimal nutrient resource for fish fry is an object of growing interest. The advantages of using Artemia include the possibility of mass cultivation under controlled conditions, the possibility of long-term storage in frozen form and resistance to external environmental conditions. Artemia, belonging to crustaceans, is a rich source of protein, fat, vitamins and minerals necessary for the healthy development of fish larvae. Due to the high content of unsaturated fatty acids, omega-3 and omega-6, fry contribute to the development of a healthy immune system, which reduces the risk of many diseases. Their small size and mobility make them available for cultivation, which ensures a high level of quality and reduces feed consumption. The results of the study show that the use of crustaceans as the main food source for fish farming contributes to improving the life, growth and health of fry. This makes them a successful type of feed in aquaculture and an optimal resource for fish farming. Further research in this area can lead to increased efficiency of fish farming, development of practices and improvement of the overall potential of the aquaculture industry. This article discusses the advantages of using Artemia, its biological value, ease of cultivation and versatility in the nutrition of various fish larvae. Various methods and technologies of growing Artemisia are analyzed, as well as their application in breeding species of fish larvae. Special attention is paid to optimizing the maximum growth of fish larvae and feeding conditions.

First Record Sparus aurata Larvae in Teluk Penyu Beach Cilacap, Indonesia, revealed by DNA Barcoding

Morphological identification often fails to reveal the taxonomic status of fish larvae. DNA barcoding using particular DNA segment is frequently successful in solving the faulty and might reveal overlooked species, including species outside their recognized geographic ranges, such as Eastern Atlantic seabream Sparus aurata. This study aims to assess fish larvae diversity in Teluk Penyu Beach, Cilacap Central Java, Indonesia, through the cytochrome c oxidase 1 barcoding. Fish larvae were collected using a larva net with a diameter of 60 cm and height of 150 cm and horizontal towing during the field trips in March and April 2021. Larvae morphotypes were determined based on their general morphological performance observed under a magnification lens according the available references. Eighteen larvae morphotypes were successfully barcoded, and 5% genetic distance was used as a species border. Fourteen fish larvae species were revealed, with intraspecific genetic distances between 0.00% and 4.12%, while intrageneric genetic distances ranged from 5.50% to 19.29%. An interesting finding was that one larva morphotype was barcoded as S. aurata with high genetic identity (99.19% to 99.68%) and low genetic distance (0.32% to 0.81%). The discovery provides the first new data on S. aurata in Teluk Penyu Beach Cilacap, Central Java, outside its recognized geographic range. Overall, this study provides information about fish larvae in Teluk Penyu Beach, essential for estimating the number and species of fish recruited in the southern Cilacap, which is vital for fisheries management. Nevertheless, new research requires further clarification of S. aurata in Teluk Penyu Beach.

Vertical variability in the diversity and abundance of fish larvae in a shallow tropical estuary in Southern Gulf of Mexico

Vertical migration in ichthyoplankton is relevant for its survive and it has been documented in estuaries with more than 10 m depth. In shallow estuaries this process is unknow or not supposed since no environmental stratification is assumed. The objective of this research is to investigate the vertical variability of fish larvae assemblages in shallow tropical estuarine zones. The model study site was the estuarine area of the San Pedro y San Pablo River located east of the Centla Wetland Biosphere Reserve in the Gulf of Mexico. The experimental design includes depth (bottom-surface), habitat type (coast-low complexity and mangrove-high complexity), circadian cycle (sunrise–midday–sunset–night), and season (dry-rainy). The ichthyoplankton were collected using a supporting net (150 cm in length, 50 cm mouth diameter, 400μm mesh size) device for simultaneous collection on the surface and bottom. Circular tows (2.7–4 km/h) were carried out for 5 min. A total of 40,968 fish larvae were collected, belonging to 13 orders, 26 families, and 38 species. The highest larval abundance expressed as mean density (693 ± 916 ind/m3), richness (4.57 ± 3.46), Shannon-Wiener diversity (1.05 ± 48.48), and Pielou evenness (0.88 ± 0.3) were recorded in the bottom. The variance component analysis indicated that the most important factors to explain the larval abundance was the depth (15.55%), the period of the day (11.20 %) and the interaction between all factors (10.51 %). Fish larvae species as Achirus lineatus, Trinectes maculatus, Etropus crossotus, and Symphurus civitatium occupied only the bottom. Despite the low depth, a vertical stratification was observed in the physicochemical parameters, especially in the salinity, being greater in the bottom than in the surface during the two seasons and habitat type and it was related with higher values of abundance, richness, and diversity of ichthyoplankton.

Digital holography for real-time non-invasive monitoring of larval fish at power plant intakes

Effective evaluation of technological and operational approaches to reduce entrainment of marine organisms at cooling water intake structures (CWIS) requires accurate organism-sensing systems. Current detection methods lead to large temporal data gaps, require tedious manual analysis, and are fatal to organisms. Here, we describe integrating deep learning with a non-lethal, non-intrusive imaging method—digital holography—to rapidly detect fish larvae. Laboratory experiments demonstrated that the instrument could successfully image fish larvae at flow rates exceeding ranges seen in CWIS. Holograms of two fish larvae species, in the presence of bubbles and detritus, were collected to build a large database for training a lightweight convolutional neural network. The model achieves 97% extraction accuracy in quantifying larvae, and distinguishing them from other particles, including detritus and bubbles, when applied to a dataset of manually classified images, exceeding previous metrics for non-lethal, accurate, and real-time detection. These results demonstrate the potential of in situ holographic imaging for monitoring endangered larval fish species at power plant intake structures, and for high-fidelity, real-time applications in monitoring aquatic ichthyoplankton.

The role of habitat complexity in the survival rates of migratory (native) and sedentary (non-native) species of fish larvae

The increasing losses of original features of many riverine environments and the consequent decline of native aquatic species are now a widely recognized problem. The main river basins of South America have been undergoing constant changes in their communities of fish, with native migratory species disappearing and the rising of sedentary exotic ones. However, few studies report experiments that qualify and/or quantify this correlation. Three experiments were conducted to evaluate the predation mortality of two species of fish larvae (native and non-native) regarding their habitat features. The hypothesis that natural features of habitat (aquatic vegetation and water turbidity) controls the survival rates of fish larvae was tested. The experiments highlight the importance of community structure on population dynamics. The native fish larvae showed to be more adapted than the non-native to using the aquatic plants for refuge. The habitat complexity can be closely related to the persistence of native migratory fish species.

Spatial distribution and seasonal variation of fish larvae in the upper 200 m of the Philippine Sea

The Philippine Sea, owing to its complicated circulation pattern and the presence of numerous seamounts, is considered to be a hotspot for biodiversity and an important fishing ground. However, to date, few studies on ichthyoplankton in the Philippine Sea have been conducted. During the summer, autumn, and winter of 2020–2021, a series of investigations were conducted to study the spatial and temporal structure of fish larvae in the Philippine Sea. A total of 65 samples were collected by vertical hauling from a depth of 200 m to the surface. A total of 882 fish larvae representing 81 distinct taxa, 49 genera, and 23 families were identified. A seasonal pattern was also observed based on the differences in abundance and dominant taxa. The abundance of fish larvae was 11.35 ± 12.46 ind./100 m3 (mean ± sd.) in summer, 5.83 ± 7.03 ind./100 m3 in autumn, and 2.57 ± 2.73 ind./100 m3 in winter. The dominant species were Vinciguerria nimbaria, Encrasicholina punctifer, and Cyclothone sp. in summer, V. nimbaria, and Ceratoscopelus warmingii in autumn, and Diaphus spp., D. garmani, and Sigmops sp. in winter. A significant latitudinal variation in fish larvae assemblages was found via cluster analysis, and two geographic groups were separated by the northern boundary of the North Equatorial Current. In addition, the fish larvae species diversity also showed a significant latitudinal gradient in autumn, which disappeared in summer. Canonical correspondence analysis indicated that the structure of fish larvae assemblages was affected by average temperature, salinity, and net primary productivity in the upper ocean and sea level anomaly. All dominant species were associated with specific niche environments. This study suggests that latitudinal zonation of fish larvae also occurs in the oligotrophic low latitude Pacific Ocean and is enhanced in autumn. These results provide multi-seasonal baseline data of fish larvae assemblage in the upper Philippine Sea, being an important reference for the planning of marine protected areas in the high seas.

Distribution and densities of fish larvae species with contrasting life histories as a function of oceanographic variables in the deep-water region of the southern Gulf of Mexico.

We describe the larval occurrence and density of six fish species with contrasting life histories and examine their relationships with oceanographic variables during two seasons in the deep-water region (> 1000 m) of the southern Gulf of Mexico based on 12 cruises (2011-2018). Given that Caranx crysos adults are neritic, larval presence close to the continental shelf indicates offshore cross-shelf transport to oceanic waters, which likely leads to mortality. Generalized additive models indicated that C. crysos density was not related with oceanographic variables, while Auxis spp. (with neritic and oceanic adults) was related to wind speed, sea surface temperature, sea surface height, and surface chlorophyll a. The mesopelagic Benthosema suborbitale, Notolychnus valdiviae and Bregmaceros atlanticus were more abundant and broadly distributed, and higher density was found in conditions indicative of higher nutrient availability and productivity, suggesting greater feeding success and survival. The distribution of the epi- and mesopelagic Cubiceps pauciradiatus extended through the southern Gulf of Mexico, and was related to wind speed, sea surface temperature, stratification and chlorophyll a. Our results suggest that the density of the neritic species in oceanic waters could be mediated by regional cross-shelf transport, while for oceanic species is linked with productivity.

Diet and food selection by fish larvae in turbid and clear water shallow temperate lakes

Fish larvae play an important structuring role for their prey and show ontogenetic shifts in diet. Changes in diet differ between species and habitats and may also be affected by turbidity (eutrophication). We investigated the diet (stomach content) and the food selection (ratio of ingested prey and prey availability) of roach and perch larvae in a clear lake and of roach, perch and pikeperch larvae in a turbid lake multiple times during spring to autumn. The diet of the fish larvae changed with size, and for roach and perch larvae between the lakes. Coexisting species of fish larvae had different diets in the two lakes, pointing to resource partitioning; yet, in the clear lake, medium-sized larvae had a high diet overlap, suggesting a competitive relationship at this developmental stage. In the clear lake, roach larvae showed diel differentiation in diet, while perch demonstrated diet shifts between habitats, which probably aided in reducing competition and also evidenced an effect of light on the larval prey capture and/or predator-fish larvae interactions. In the turbid lake, roach and perch larvae did not reveal differences in diet between habitats or time of the day, owing to homogeneity of food items and poor light conditions. However, the diet of pikeperch larvae differed between day and night following daily variations in the abundance of its preferred prey. The roach larvae were highly selective for Bosmina, Daphnia and benthic cladocerans, perch larvae generally consumed what was available, while pikeperch primarily preyed on cyclopoid copepodites. We conclude that turbidity acted as a cover for fish larvae in the turbid lake. Under eutrophication-induced turbidity scenarios the effects of fish larvae on their prey are stronger (i.e., high selectivity for several resources) than that of larvae in clear waters, creating a negative feedback on the path to restore water clarity.

The influence of habitat association on swimming performance in marine teleost fish larvae

AbstractLatitude and body size are generally considered key drivers of swimming performance for larval marine fishes, but evidence suggests that evolutionary relationships and habitat may also be important. We used a comparative phylogenetic framework, data synthesis and case study approach to investigate how swimming performance differs among larvae of fish species across latitude. First, we investigated how swimming performance changed with body length, and we found that temperate reef fishes have the greatest increases in swimming performance with length. Secondly, we compared differences in three swimming performance metrics (critical swimming speed, in situ swimming, and endurance) among post‐flexion larvae, whilst considering phylogenetic relationships and morphology, and we found that reef fishes have higher swimming capacity than non‐reef (pelagic and non‐reef demersal) fishes, which is likely due to larger, more robust body sizes. Thirdly, we compared swimming performance of late‐stage larvae of tropical fishes with oceanographic data to better understand the ecological relevance of their high‐capacity swimming. We found that reef fishes have high swimming performance and grow larger than non‐reef fish larvae, which we suggest is due to the pressures to find a specific, patchily distributed habitat upon which to settle. Given the current bias towards studies on percomorph fishes at low latitudes, we highlight that there is a need for more research on temperate reef fish larvae and other percomorph lineages from high latitudes. Overall, our findings provide valuable context to understand how swimming and morphological traits that are important for dispersal and recruitment processes are selected for among teleost fish larvae.

Urban stormwater and crude oil injury pathways converge on the developing heart of a shore-spawning marine forage fish

Understanding how aquatic organisms respond to complex chemical mixtures remains one of the foremost challenges in modern ecotoxicology. Although oil spills are typically high-profile disasters that release hundreds or thousands of chemicals into the environment, there is growing evidence for a common adverse outcome pathway (AOP) for the vulnerable embryos and larvae of fish species that spawn in oiled habitats. Molecular initiating events involve the disruption of excitation-contraction coupling in individual cardiomyocytes, which then dysregulate the form and function of the embryonic heart. Phenanthrenes and other three-ring (tricyclic) polycyclic aromatic hydrocarbons (PAHs) are key drivers for this developmental cardiotoxicity and are also relatively enriched in land-based urban runoff. Similar to oil spills, stormwater discharged from roadways and other high-traffic impervious surfaces contains myriad contaminants, many of which are uncharacterized in terms of their chemical identity and toxicity to aquatic organisms. Nevertheless, given the exceptional sensitivity of the developing heart to tricyclic PAHs and the ubiquitous presence of these compounds in road runoff, cardiotoxicity may also be a dominant aspect of the stormwater-induced injury phenotype in fish early life stages. Here we assessed the effects of traffic-related runoff on the embryos and early larvae of Pacific herring (Clupea pallasii), a marine forage fish that spawns along the coastline of western North America. We used the well-characterized central features of the oil toxicity AOP for herring embryos as benchmarks for a detailed analysis of embryolarval cardiotoxicity across a dilution gradient ranging from 12 to 50% stormwater diluted in clean seawater. These injury indicators included measures of circulatory function, ventricular area, heart chamber looping, and the contractility of both the atrium and the ventricle. We also determined tissue concentrations of phenanthrenes and other PAHs in herring embryos. We find that tricyclic PAHs are readily bioavailable during cardiogenesis, and that stormwater-induced toxicity is in many respects indistinguishable from canonical crude oil toxicity. Given the chemical complexity of urban runoff, non-tricyclic PAH-mediated mechanisms of developmental toxicity in fish remain likely. However, from the standpoint of managing wild herring populations, our results suggest that stormwater-driven threats to individual survival (both near-term and delayed mortality) can be understood from decades of past research on crude oil toxicity. Moreover, Pacific herring embryos are promising sentinels for water quality monitoring in nearshore marine habitats, as in situand sensitive indicators of both toxic runoff and the effectiveness of pollution reduction efforts such as green stormwater infrastructure.

Dams in the Amazon: The importance of maintaining free‐flowing tributaries for fish reproduction

Abstract Free‐flowing tributaries are important for the maintenance of fish diversity in dammed systems. In relation to the reproduction of fish species, the role of a free‐flowing tributary was evaluated and compared with that of a dammed tributary downstream of large dams in the Madeira River, one of the main tributaries of the Amazon River. Two hypotheses were tested: (i) the densities of the ichthyoplankton differ between the dammed and the free‐flowing tributaries; and (ii) the free‐flowing tributary contributes a greater diversity of fish larvae species to the assemblage structure of the main stem than the dammed tributary. Fish eggs and larvae were sampled at five sites: one in each tributary (Jamari – dammed – and Machado – free‐flowing) and three in the main stem (Madeira River), upstream and downstream from the mouth of each tributary. Fitted Bayesian models showed that the densities both of eggs and larvae were more than twice as high in the free‐flowing tributary than in the dammed tributary. The results also indicated that the free‐flowing tributary makes a major contribution to the fish assemblage structure of the Madeira River, whereas the dammed tributary does not have a significant influence on the main stem assemblage structure. The results demonstrate the importance of conservation and maintenance not only of the Machado River but also of other free‐flowing tributaries in dammed basins, especially those basins with high biodiversity, such as the Amazon. Moreover, this study helps inform the decision‐making process regarding the location of new dams, which is critical in fish diversity conservation.

Identification of larval stages of fish in southeastern coastal waters of the Caspian Sea- Golestan Province

This study was carried out to develop a practical guide for identifying species of fish larvae in coastal waters of Caspian Sea-Golestan Province. A total of 18 sample sites in the Caspian Sea and 6 sampling sites in the Gorgan Bay was sampled monthly from March to September 2015 with a Bongo net (diameter, 46cm; mesh size, 330 µm). Most of the fish larvae belonged to postflexion and transitional stages. Morphological and meristic measurements were made. Fish larvae included Atherina boyeri, Rutilus rutilus, Rutilus firisii kutum, Cyprinus carpio, Liza saliens, Liza aurata and Gambusia holbrooki, representing 5 genera in 4 families. Results showed Cyprinus sp. and Rutilus sp. separated based on pigments patterns on the body while R. rutilus and R. frisii kutum were discerned by the number of pre-anal myomers. Liza spp. could be differentiated by different pigments patterns and some morphometric characters including eye diameter, body depth, and head length. The results of this study revealed that in contrast to the current perception, the analysis of the morphometric variation of Liza sp., Rutilus sp., and Cyprinus carpio fry could be used for their discrimination.

Ихтиопланктон Юго-Восточной Балтики в летний сезон: современные изменения в распределении и численности икры и личинок массовых видов рыб

The aim of ichthyoplankton studies in July 2019 was to monitor the distribution and estimate the abundance of: 1) eggs and larvae of mass pelagophilous fish species (cod, sprat) in deep-water areas; 2) larvae of small-sized benthic fish species inhabiting the shallow coastal zone of the South-Eastern Baltic Sea (the exclusive economic zone of the Russian Federation). It was noted, the main concentrations of cod and sprat eggs were in the northern part of the area (southern slope of Gotland Deep). Aggregations with a noticeably lower abundance of eggs were observed in the Gdansk basin. In July 2019, the average abundance of cod eggs (3.4 ind./m2) was higher than in the years without strong North Sea advections according to observations in the 1990–2000. Although the reproduction of sprat was nearing completion, in July its eggs dominated the ichthyoplankton assemblage of the deep-water zone, tenfold exceeding the numbers of cod eggs. In the composition of the ichthyoplankton of the shallow-water zone, 7 species of fish larvae were found, among which the sand goby dominated in numbers. Its small-sized larvae were most abundant above depths from 20 to 40 m, which made it possible to identify this depth range as an area of intensive spawning of the species. The decrease in the number of sand goby larvae in the 2010s, compared to the beginning of the 2000s, could be associated with the spread of the Ponto-Caspian invader round goby in the coastal zone, small-sized fry of which were also found in July 2019 in the ichthyoplankton of the coastal zone.

ЭКОЛОГИЧЕСКИЕ АСПЕКТЫ ОРГАНИЗАЦИИ МНОГОВИДОВЫХ ГРУППИРОВОК ЛИЧИНОК РЫБ В ЛИТОРАЛИ РЫБИНСКОГО ВОДОХРАНИЛИЩА

The paper presents the results on the study of specific, spatial-temporal, age and trophic structures of groups of fish larvae feeding in the littoral zone of the Rybinsk Reservoir. The species composition and distribution of fish larvae were determined in biotopes of the protected vegetated coastal area in years of different water content. It has been pointed out that the dynamics of zooplankton in the spring period corresponds to the age-related changes in consumption of different groups of hydrobionts by fish larvae. There have been investigated the environmental factors ensuring the dissociation in time and space of potential competitors of the same trophic level accompanied by the divergence of food spectra and the division of food resources. Using as the example one of the structural and functional elements of the littoral biocenosis (multi-species groups of fish larvae), the role of the trophic factor which provides the organization and functioning of this biological system and gives it a balanced and integral character has been demonstrated. At the same time, the balance of food relationships was provided by such mechanisms as differentiation of individuals of different species of fish larvae according to the age principle, change of food objects during ontogenesis, and spatial separation.

Fish larvae as indicator species of interannual environmental variability in a subtropical transition area off the Baja California peninsula

The aim of this work was to determine if the variation patterns in the abundance of dominant species of fish larvae in the transition zone off Bahía Sebastián Vizcaíno, Mexico, could be used as indicators of interannual environmental variability, and how larval fish assemblages respond to this environmental variability during the period 1997–2013. With the 16 years of plankton data in the southern region of the California Current System, anomaly curves of larval abundance were calculated, from which the temporal abundance patterns of the dominant fish larvae of the mesopelagic, epipelagic and demersal environments were obtained. Classification and ordination analyses were carried out to obtain the larval fish assemblages as well as their relations with environmental variables (sea surface temperature, surface salinity, concentration of Chlorophyll-a and zooplanktonic volume) and climatic indexes (ONI, MEI, PDO and NPGO). Results showed a high positive correlation between the mesopelagic abundance with MEI and PDO indices, demonstrating their affinity with warm oceanic waters, while there were not statistically significant correlation between the climatic indexes and the epipelagic (Sardinops sagax and Engraulis mordax) or demersal species (Synodus lucioceps). The interannual variability of the abundance of three dominant mesopelagic species (Vinciguerria lucetia, Diogenichthys laternatus and Cyclothone signata) show that these species had a clearer response to environmental variability than epipelagic and demersal species. Trends in the abundance of mesopelagic species larvae and their high correlation values with the environmental variables used, demonstrate their potential as indicators of environmental change of the pelagic ecosystem in the transitional area off Bahía Sebastián Vizcaíno.

Early life history phenology among Gulf of Alaska fish species: Strategies, synchronies, and sensitivities

Synthesis of four decades of Gulf of Alaska ichthyoplankton data indicates that species diversity and total abundance peaks during spring, a common pattern in temperate and sub-arctic ocean regions due to synchrony with the spring peak in plankton production. Nevertheless, fish larvae occur in the plankton at all times of year and peak abundance periods vary significantly by species and habitat. Larval size at hatching and at transformation to the juvenile stage is also highly variable and associated with a variety of larval durations and temporal supply of larval cohorts to pelagic habitats. This phenological diversity represents variability in exposure and adaptation to seasonal cycles in the ocean. Water temperature, winds and currents, and availability of suitable zooplankton prey vary significantly on a seasonal scale affecting degrees of synchrony among larval species with optimal environmental conditions for growth, transport and survival. This synchrony is also affected by interannual shifts in the oceanographic environment, and different early life phenologies among species generate different sensitivities to such interannual variability. Early life history strategies and synchronies are evaluated here and environmental sensitivities are proposed for the numerically dominant species of fish larvae occurring in Gulf of Alaska plankton, including commercially and ecologically important species. For winter to early spring spawners, cold temperatures are an advantage in terms of slowing development so that larvae do not use up all their lipid reserves prior to optimal availability of suitable larval zooplankton prey. Interannual variability in winter temperature may therefore be a good indicator of survival outcomes, especially as influenced by the timing of the switch to exogenous feeding. Variability in temperature-influenced larval growth during late spring and summer months may be less consequential in maintaining synchrony with larval food availability for spring-summer spawners. Rapid growth in association with warm summer conditions facilitates access to a wide size range of prey organisms and minimizes critical periods of vulnerability to trophic mismatch. The Gulf of Alaska is a highly advective environment; storms and alongshore winds promote onshore advection of surface waters. This onshore Ekman transport is strongest during winter and spring when deep water spawned larvae are most abundant over the slope and require access to the shelf. Enhanced shoreward transport of larvae in the canyons intersecting the slope is also an important mechanism. Interannual variability in such transport mechanisms may be critical in determining early ontogeny survival for these species. During all seasons, but especially spring and summer, there are species of larvae for which retention nearshore is vital for survival and mesoscale oceanographic features as well as larval behavioral abilities may be crucial. Annual patterns in phytoplankton and zooplankton production and abundance indicate high-amplitude variation in the composition of prey fields available to larvae, including variability in abundance and the size spectrum of organisms that larvae might encounter and consume. Food limitation seems less likely for larval species that are most abundant in spring-summer than for species with peak abundance in winter-spring. It is probable that the more selective a species is in terms of zooplankton prey, the more susceptible that species is to a trophic mismatch. Species-specific intrinsic rates and morphological development during early ontogeny also influence the interaction of larvae with their environment, and larval growth trajectories can be quite different even among species with identical early life phenology. This insight clearly indicates that although phenology is critical, timing is not everything and all fish larvae are not equal. For the 23 species and two genera of fish in this study, a synoptic overview is provided of their early ontogeny environmental synchronies and proposed sensitivities. This ecological synthesis of phenologies helps us characterize vulnerability and resilience factors for intervals of the planktonic phase in the pelagic environment. It also identifies environmental signals that could be tested as species-specific ecosystem indicators of population trends for fish stocks in the Gulf of Alaska. Further, understanding seasonal dynamics in the ichthyoplankton is considered important for gauging food availability and energy flow more broadly in this and other pelagic ecosystems, as well as to understanding environmental forcing on the fish populations themselves.

Interaction of oceanography patterns towards the abundance of phytoplankton, zooplankton and ichthyoplankton in teluk penyu waters of Cilacap

Coastal waters of Teluk Penyu-Cilacap district is an enlarging area for many species of fish larvae. The waters is directly influenced by the physical, chemical and biological of Indian Ocean patterns. Fish communities inhabit in gulf waters to take advantage of the high productivity in the coastal waters to support their livelihoods. The gulf area is usually associate with other productive ecosystems i.e. rivers that empties into it and mangrove forests. The study aim is to analyze the influence of oceanography pattern to the existence of ichthyoplankton [fish larvae] inhabit at Teluk Penyu waters of Cilacap district. Sampling is conducted monthly from April - June 2009 at 3 sites. The sites were set 1 mile of distance from coastline at Teluk Penyu Cilacap, PPSC and RSPC waters. Fish larvae were collected using larvae net mesh size 0.5 mm and 75 cm mouth diameter and phytoplankton and zooplankton are collected using plankton net . Larvae net was towed on the surface of the waters using a motorized boat with a speed 1 knot. Data were analyzed statistically based on Principal Components Analysis/PCA. 30 species of phytoplankton and 25 species of zooplankton species were identified from the waters. The species of phytoplankton and zooplankton were obtained difference species at each site. The highest abundance of phytoplankton were species of Chaetoceros and the abundance of zooplankton from the highest subsequence are species of Coelosphaerium dubium and Platydorina. The highest of relative abundance of ichthyoplankton in Teluk Penyu tourism waters was obtained 41,463% of the crawfish [Crumrnophthalmus spp.], followed by pheasant fish [Auriglobus nefastus] 8.53667%, and swordfish (Chirocentrus dorab spp.) 2.439%, and fish beloso [Tumbilic saurida] and gulamah fish (Johnius dussumieri) which are 1.2195%. The abundance of phytoplankton and zooplankton associated to ichthyoplankton abundance. The Southern of Teluk Penyu gulf waters was highest abundance area of ichthyoplankton.

Seasonal Variation in Species Composition of Ichthyoplankton in Northern Jinhae Bay, Korea

Fish eggs and larvae were collected in July and November of 2013 and January and May of 2014 to determine sea sonal variation in the species composition of ichtyoplankton. Samples were classified based on morphological char acteristics. Fish eggs were identified as belonging to five taxa; the most dominant species of fish eggs was Engraulis japonicus (62.05%) followed by Sardinops melanostictus (21.02%) and Leiognathus nuchalis (13.71%). These three species accounted for 96.8% of the total number of fish eggs collected. Larvae of 17 species in six families, and six orders were collected. The most dominant species of fish larvae was E. japonicus (51.79%), followed by L. nuchalis (12.59%) and Omobranchus elegans (12.08%). These three species accounted for 76.46% of the total number of larvae collected. Jinhae Bay was identified as a major spawning and nursery ground for fish species inhabiting in the south coast of Korea, such as E. japonicus, L. nuchalis, S. melanostictus, and Omobranchus elegans. Therefore, management of marine fish resources in the South Sea should necessarily include the ecological management of Jinhae Bay.

How "Godzilla" El Niño Affected Tropical Fish in Low-Oxygen Zone

A warm period unexpectedly boosted some species of fish larvae off the coast of Mexico.