Naupliar Stages Research Articles

GROWTH IN NURSERY AND GROW-OUT PHASES OF WHITE SHRIMP AFTER IMMERSED IN RECOMBINANT GIANT GROUPER GROWTH HORMONE

The growth of white shrimp (Litopenaeus vannamei) can be improved by using recombinant fish growth hormone through immersion. This research was performed to evaluate the white shrimp growth at nursery and grow-out phases after recombinant giant grouper growth hormone (rElGH) immersion. Shrimp were immersed at different stages in one liter seawater containing 15 mg rElGH for two hours. At the nursery stage 30,000 PL4 that previously immersed at nauplius stage (treatment A1), at PL4 (treatment B1) and control without rElGH immersion (K1) were reared in fiber tanks containing 750 L seawater for 8 days. At the grow-out phase, 100 PL11 that have been immersed in rElGH solution at nauplius stage (treatment A2), at PL4 (B2), PL11 (C2) and control without rElGH immersion (K2) were separately reared in fiber tanks containing 750 L seawater for 55 days. Each treatment consisted of three replications. The results showed that at the end of the nursery phase, B1 treatment increased 19% of body length, 30.2% of the body weight and decreased the coefficient of length variation 34.9% compared to control K1 (P<0.05). At the grow-out phase, C2 treatment enhanced 38.2% of body weight and 32% of biomass compared with control K2 (P<0.05). Thus, hatchery is better to immerse PL4, and the farmer should used rElGH-immersed PL11 for growing-out.Keywords: growth promoting, nursery, grow out, Litopenaeus vannamei, rElGH

Effect of chlorination on barnacle larval stages: Implications for biofouling control and environmental impact

Continuous low-dose chlorination (CLDC, 0.2 ± 0.1 mg l−1) is practised to control mussel settlement in industrial cooling systems. However, its effect on larval barnacles is poorly understood. Experiments were carried out with larvae of the barnacle Amphibalanus reticulatus to assess: 1) chlorine toxicity to discrete naupliar stages, 2) effect of transient chlorine exposure of nauplii on subsequent larval development and 3) effect of chlorine on cypris settlement and metamorphosis. Individual naupliar stages showed different levels of sensitivity to chlorine exposures with the stage II nauplii being the most susceptible to in-use levels (0.2 ± 0.1 mg l−1) of chlorination. Short term exposures (3–20 min) to 0.2 mg l−1chlorine did not prevent larval settlement. A significant percentage of treated cyprid larvae (non-feeding stage) survived, settled and metamorphosed to juveniles. A fraction of the chlorine-treated cypris larvae precociously metamorphosed into juveniles, bypassing cementation to substratum. About half of the pre-competent larvae (naupliar stages) exposed to in-use levels of chlorine failed to reach cypris stage, indicating that CLDC can impact barnacle larval development in the sea. In barnacle dominated systems, use of alternative control strategies/biocides may be required.

Population Dynamics of Cyclopoid Copepods in Lake Kinneret (Israel)

Reports on the Kinneret zooplankton in general and particularly on copepods are dealing recently with numerical densities of feeding habit classes. Nevertheless, for the evaluation of the integrated role of copepod assemblages in the entire lake ecosystem, their life cycle stages fluctuations are essential. It was not done in previous reports. Therefore, long term analysis of the cyclopoid copepods life stages dynamics in Lake Kinneret was carried out. Due to information availability, two complementary methods of density concentrations were evaluated for two consecutive data sets: 1) 1969-1985 numerical (No/L) documentation of life cycle stages of nauplii (I - III and III - V), copepodites (I, II, III, IV, V) and adults; 2) 1969-2002 monthly averages of wet biomass density (g/m2) of zooplankton major groups combined with metabolic rates. nauplii densities represent June-August peaks and older stages spring decline and high levels during summer-early winter. Polynomial Regressions between Numerical annual averages of predator and Herbivore stages as well as young vs. older life stages indicate significant relations. During winter-spring season, temperatures are optimal for cyclopoid growth as a result of the high efficiency of metabolic activity and the low pressure of fish predation. The high rate of metabolism and intensive fish predation in summer enhance low densities of adult cyclopoids.

Resurrection and redescription of Hatschekia cylindrica Shiino, 1957 (Copepoda, Siphonostomatoida, Hatschekiidae), with description of its developmental stages

Hatschekia cylindrica Shiino, 1957 is resurrected and redescribed based on newly obtained specimens, and all developmental stages except copepodid II are described based on free-living larvae reared from eggs detached from ovigerous females, as well as on both sexes of copepodids III-V recovered together with adults from Pseudolabrus sieboldi Mabuti & Nakabo, 1997 (Pisces, Labridae). There are three naupliar stages preceding the infective copepodid I and the sexes are distinct after copepodid III, as in the two other species of Hatschekia studied thus far in this respect.

EFECTO DE LAS CONDICIONES DE TRANSPORTE, RECEPCIÓN, ACLIMATACIÓN Y SIEMBRA DE NAUPLIOS DE LITOPENAEUS VANNAMEI (BOONE, 1931) SOBRE LA SOBREVI

In order to idontify initial factors that can affect shrimp postlarvae survival dunng larval rearing, three larval rearing facilities from the Caribboan coast of Colombo were sampled for 71 nauplii batches during 10 months ol 1996. For each batch. qualitative variables (origin, transportation mode, presence of bacteria in transport wator) and quantitative variables (transportation timo and donsity, phystcochemical parameters of the water, proportion of each nauplii stage and of deformed nauplii) were monitored. Wator quality and density (naupJii/1) variables wore monitored dunng tho vtfiole process of nauplii packing, transport, reception, accllrnaiizatlon and stacking To evaluate the relationship between qualitative variables and larva! rearing survival, a multiple tactor variance analysis was run, while, for quantitative variables, a stúpwise multiple ragressron model was ifevefoped VanaWes with slgnilleaüvo (PoO.OS) influence on larval roaring survival were the Iran spallation modo (with srnsil private aircraft, avarage survival was 45%. compared to 35% wittl a pressurized commercial aircraft), tha pfcscnce of bacteria (growing an T.C.B.S. motila) in nauplii transport water {survival witfKMJt these bacteria in water was 59% compared with 40°,n when these bacteria were observed! and the percentage of deformed nauplii, Furthermore, the specific presence of bacleria like Vibrio motschrtikovii, Flavobactgnum spp. afid Aicaltgores spp in nauplii transport water was a worsing fectgr,

The deleterious effect of diatoms on the biomass and growth of early stages of their copepod grazers

Diatoms are key phytoplankton species in the world oceans and essential in the transfer of energy through marine food chains. Their beneficial role has been questioned after the discovery that some diatom species produce teratogenic compounds such as polyunsaturated aldehydes and other oxylipins that induce abortions, poor larval development and high offspring mortality in many invertebrates. To test whether maternal and post-embryonic diatom diets affected development in the copepod Paracartia latisetosa, we carried out experiments in which the PUA-producing diatom Skeletonema marinoi (SKE) was fed to this copepod species. Controls were run with the dinoflagellate, Prorocentrum minimum (PRO), which does not produce any of these compounds. Four treatments were tested: both mothers and progeny always fed on either SKE or PRO, and those in which mothers received either PRO or SKE, and neonates were switched to the other diet. Our results show that a SKE/SKE diet induced lower egg production and egg viability, as well as slower embryonic development than the control diet. Naupliar development was negatively affected with the diatom diet which blocked the metamorphosis of larvae at N3, 4days after hatching, compared to the control diet that allowed for normal naupliar development in 10days. Nauplii reared on PRO and spawned by females fed on SKE were able to complete development, but only after 11days, whereas larvae reared on SKE spawned by females fed on PRO were arrested at the N5 developmental stage, 12days after hatching. Apoptotic TUNEL-positive nauplii were detected with the SKE diet, indicating imminent death. Significant differences were also recorded by comparing biomass of equivalent naupliar stages obtained for each treatment, and the overall mean biomass female−1day−1 for each diet. Growth inhibition due to oxylipin-producing diatoms may have important consequences on prey–predator relationships and on the biomass flux through marine food chains.

Naupliar and Metanaupliar Development of Thysanoessa raschii (Malacostraca, Euphausiacea) from Godthåbsfjord, Greenland, with a Reinstatement of the Ancestral Status of the Free-Living Nauplius in Malacostracan Evolution.

The presence of a characteristic crustacean larval type, the nauplius, in many crustacean taxa has often been considered one of the few uniting characters of the Crustacea. Within Malacostraca, the largest crustacean group, nauplii are only present in two taxa, Euphauciacea (krill) and Decapoda Dendrobranchiata. The presence of nauplii in these two taxa has traditionally been considered a retained primitive characteristic, but free-living nauplii have also been suggested to have reappeared a couple of times from direct developing ancestors during malacostracan evolution. Based on a re-study of Thysanoessa raschii (Euphausiacea) using preserved material collected in Greenland, we readdress this important controversy in crustacean evolution, and, in the process, redescribe the naupliar and metanaupliar development of T. raschii. In contrast to most previous studies of euphausiid development, we recognize three (not two) naupliar (= ortho-naupliar) stages (N1-N3) followed by a metanauplius (MN). While there are many morphological changes between nauplius 1 and 2 (e.g., appearance of long caudal setae), the changes between nauplius 2 and 3 are few but distinct. They involve the size of some caudal spines (largest in N3) and the setation of the antennal endopod (an extra seta in N3). A wider comparison between free-living nauplii of both Malacostraca and non-Malacostraca revealed similarities between nauplii in many taxa both at the general level (e.g., the gradual development and number of appendages) and at the more detailed level (e.g., unclear segmentation of naupliar appendages, caudal setation, presence of frontal filaments). We recognize these similarities as homologies and therefore suggest that free-living nauplii were part of the ancestral malacostracan type of development. The derived morphology (e.g., lack of feeding structures, no fully formed gut, high content of yolk) of both euphausiid and dendrobranchiate nauplii is evidently related to their non-feeding (lecithotrophic) status.

Identification and molecular characterization of nitric oxide synthase (NOS) gene in the intertidal copepod Tigriopus japonicus

In copepods, no information has been reported on the structure or molecular characterization of the nitric oxide synthase (NOS) gene. In the intertidal copepod Tigriopus japonicus, we identified a NOS gene that is involved in immune responses of vertebrates and invertebrates. In silico analyses revealed that nitric oxide (NO) synthase domains, such as the oxygenase and reductase domains, are highly conserved in the T. japonicus NOS gene. The T. japonicus NOS gene was highly transcribed in the nauplii stages, implying that it plays a role in protecting the host during the early developmental stages. To examine the involvement of the T. japonicus NOS gene in the innate immune response, the copepods were exposed to lipopolysaccharide (LPS) and two Vibrio sp. After exposure to different concentrations of LPS and Vibrio sp., T. japonicus NOS transcription was significantly increased over time in a dose-dependent manner, and the NO/nitrite concentration increased as well. Taken together, our findings suggest that T. japonicus NOS transcription is induced in response to an immune challenge as part of the conserved innate immunity.

Ontogenetic Changes in Vulnerability of the Prawn Fenneropenaeus indicus to UV-B Radiation Help Explain Ontogenetic Habitat Shifts

The Indian Ocean white prawn (Fenneropenaeus indicus H. Milne Edwards, 1837) is distributed across the Indian Ocean, from southern Africa to northern Australia and the Red Sea, and is also present in all of South-East Asia, where F. indicus is a major commercial fishery species. F. indicus has been domesticated for aquaculture and is extensively cultured in farms throughout South-East Asia, India, the Middle East, Saudi Arabia, and eastern Africa (Ling et al. 1999). F. indicus is a non-burrowing prawn species preferring a sandy or muddy bottom, and although active at both day and night, it has been shown to display clear daily rhythms in activity, being less active at night (Natarajan 1989). F. indicus has a complex ontogenetic developmental cycle involving 12 stages distributed in three planktonic larval forms (6 nauplii stages, N-1 to N-6; 3 zoea stages, Z-1 to Z-3; and 3 mysis stages, M-1 to M-3). F. indicus develops from hatching to the post larva (PL) stage over 10 to 18 days in natural conditions (Muthu et al. 1978) and 13 to 14 days under hatchery conditions (Silas et al 1985). As many decapods, F. indicus also has a tri-phasic life cycle (Pitman and McAlpine 2003). The prawn matures and breeds mostly in offshore coastal waters, and the larvae are advected in the neuston until recruiting to their estuarine habitats (Forbes and Cyrus 1991). The PL grows in coastal estuaries, backwaters, or lagoons with a particular preference for mangrove habitats (De Freitas 1986; Mohan and Siddeek 1996; Ronnback et al. 2002), where they spend the juvenile and sub-adult stages, before migrating to open coastal habitats for breeding. Larvae are often present in the neuston, except in the period of maximum solar radiation. Seasonal studies off Kochi (Arabian Sea, India) showed that F. indicus larvae are rare in the plankton from May to September (George 1962; Rao 1964). Whereas late larval stages, PL, and juveniles inhabit shaded environments, such as mangrove creeks, the larvae are pelagic and can be subjected to high irradiance in the water column in tropical and subtropical regions. Moreover, this species is reared in shallow aquaculture ponds and floating cages (Walford and Lam 1987), which can also receive high solar radiation in tropical and subtropical regions. High light intensities have been reported to be detrimental for the survival of larval stages of penaeid prawn, which are reared under dim light conditions to increase spawning and early survival success in aquaculture (Wurts and Stickney 1984). The shaded habitat of the PL, in mangrove creeks, the low abundance of planktonic larvae during the months of peak solar radiation, and the light-sensitivity of early life stages all point at a vulnerability of F. indicus larvae to high solar radiation and particularly ultraviolet-B (UV-B) radiation as the most damaging component of solar radiation (Hader et al. 2007; Hansson and Hylander 2009). Because of its commercial importance, the physiology, growth, and behavior of F. indicus have been extensively studied (Kutty et al. 1971; Colvin 1976; Emmerson 1984). The resistance of PL to changes in environmental conditions, Communicated by Charles Simenstad

MicroNESS: an innovative opening–closing multinet for under pack-ice zooplankton sampling

Quantitative sampling of zooplankton communities from ice-covered waters presents many technical and logistic difficulties. Currently available techniques enable only vertical tows through relatively small ice holes, and the filtered volumes are generally low. For these reasons, we developed and tested Micro-Net Environmental Sampling System (MicroNESS), an innovative small-sized opening–closing multinet device carried by a ROV for horizontal and oblique sampling of the under-ice zooplankton community. MicroNESS design ensures a filtration efficiency close to 90 % due to the relevant filtration open area ratio (~4) and exhibited only limited effects of clogging and avoidance for optimal speed of 0.35 ms−1 and towing duration not longer than 14 min with mean filtered volumes in the order of 11 m3. MicroNESS was successfully tested in Terra Nova Bay (Antarctica). A total of 96 tows were carried out to sample the zooplankton in the waters below the 2.6-m-thick pack ice, far from the ice hole, at selected depths (3.5, 4.5, 5.0, 6.0, 7.0, 10.0 and 20.0 m). Overall, more than 70,000 specimens were identified, mostly copepod taxa, which showed a size range from the small Stephos longipes nauplius stage I (0.11 mm) to the large adult females of Calanoides acutus (4.8 mm). The comparison among the ice-associated copepod communities collected by MicroNESS and those of three traditional sampling techniques showed that MicroNESS can provide useful insights about changes in composition, biomass and particle size structure of this key plankton component, especially on a short timescale during ice melting.

Influence of CO2-induced seawater acidification on the development and lifetime reproduction of Tigriopus japonicus Mori, 1938

Ocean acidification is changing the carbonate system of the world’s oceans and has been driving all marine organisms to live in increasingly acidic environments. Tigriopus japonicus is an ideal standard test animal in sea water. In the present study, we investigated the influence of carbon dioxide (CO2)-induced seawater acidification on the development and lifetime reproduction of T. japonicus to accumulate basic data for assessing the potential impact of ocean acidification. The harpacticoid copepods were exposed in seawater equilibrated with CO2 and air to reach pH 8.0 (control), 7.7 (the predicted ocean pH by 2100), 7.3 (the predicted ocean pH by 2300) and 6.5 (an extreme condition relevant to industrial acid waste discharge or leakage from CO2 seabed storage). Survival was found to be unaffected following the 56 day exposure period. Significant retardation of development rates of the nauplius stage was observed at pH 6.5, while the development time of the copepodite stage was unaffected. Acidification did not affect the number of broods but it significantly reduced the hatching success of egg sacs at pH 6.5. Total production of nauplii over the lifetime of female copepods was significantly reduced at pH 7.3. Over successive broods, nauplius production was significantly affected by exposure time, pH and their interaction. Shedding of unhatched egg sacs by females mainly occurred in the late breeding stage at pH 7.3 and 6.5. Our results indicated that T. japonicus adults are tolerant to the ocean acidification conditions predicted for the year 2100, but the early development and reproductive capacity of females could be impaired by long-term exposure to more severe acidification conditions (pH 7.3 and 6.5). More long-term studies on a wider range of copepod species from different taxa and different marine habitats are urgently required to predict the fate of marine copepod communities in future oceans.

Early life history of Neocalanus plumchrus (Calanoida: Copepoda) in the western subarctic Pacific

The life history of copepods during nauplius stages has rarely been studied, because of difficulties in identification. This study describes the development of an identification method that uses integrated microscopic analysis and real-time PCR based method to distinguish and estimate the abundance of pelagic calanoida nauplii, Neocalanus plumchrus, and to determine their phenology and ontogenetic vertical migration (OVM) in the Oyashio region. The overall approach of identification included: classify field samples of calanoida nauplii into six developmental stages by microscopic analysis, determining the Cq values from each representative nauplii by real-time PCR using specie specific probe and primer pair for N. plumchrus, calculating the |ΔCq| values from the standard curve, distinguish N. plumchrus nauplii by the criterion of |ΔCq|⩽2, and calculate the abundance of N. plumchrus nauplii using results obtained from microscopic analysis and real-time PCR. Validation of the method showed that our real-time PCR based approach could identify N. plumchrus nauplii in field samples with as low as 9% of underestimation, the effect of which is negligibly low on the investigation. The results showed that early nauplius stages (first and second nauplius stages: N1 and N2, respectively) were observed during the period from October 2009 to May 2010. Spawning females were also observed during the same period, and these results confirm that the spawning period of N. plumchrus is at least 8months long. N3 was the most dominant stage in October 2009, January, and March 2010, the distribution depth of N3 was between 500m and 2000m in October 2009 and their vertical distribution range was extended until April 2010. Late stages (N4–N6) were rarely observed during the period from October 2009 to March 2010, and they occurred abundantly from the surface layer (0–20m) in April 2010. The dominance of N3 from October to March and the sudden occurrence of later stages in April indicate arrested development of N3 in the mesopelagic layer.

Pelagic microalgae as suitable diets for the benthic harpacticoid copepod Tigriopus japonicus

It has been reported that certain microal- gae have the ability to cause various negative effects on pelagic calanoid copepods. However, whether such pelagic microalgae have similar negative effects on benthic copepods has had little attention. The results of the present study indicated that both benthic naupliar and copepodite stages of the harpacticoid copepod Tigriopus japonicus could effectively utilize five species of pelagic microalgae to complete their development. The effects of different concentrations of various microalgae species on naupliar survival were significant; however, no significant effects on copepodite survival were detected. When fed with two diatoms Chaetoceros muelleri and Skeletonema costa- tum as well as the dinoflagellate Prorocentrum micans and the chrysophyte Isochrysis galbana at high concentrations (C8.50 lgC ml -1 ), the survival of both naupliar and copepodite stages of T. japonicus was more than 90%. However, when the diatom Nitzschia closteriumf. minutissima was fed at the high concentrations of 8.50 lgC ml -1 , the naupliar sur- vival was 76.3 ± 3.2 %. Interestingly, the negative effects of N. closterium f. minutissima as a diet in the naupliar stage did not affect the survival of the copepodites, which may be explained by increased mobility of copepodites.

Large-scale dinoflagellate bloom species Prorocentrum donghaiense and Karenia mikimotoi reduce the survival and reproduction of copepod Calanus sinicus

Large-scale blooms of dinoflagellates, such as Prorocentrum donghaiense and Karenia mikimotoi, have occurred frequently in the East China Sea (ECS) in recent decades. However, little is known about their effects on the entire life history of copepods. Under laboratory conditions, we investigated the effects of these two common dinoflagellates on the survival of Calanus sinicus individuals at different stages and on reproduction of this copepod. Compared with the control treatment (Skeletonema costatum), the presence of P. donghaiense and K. mikimotoi decreased the survival rates of adults and nauplii during the 16 days of the experiment. Survival of nauplii decreased to 49% and 48%, respectively, relative to the nearly 80% survival of adults. Among the six stages of nauplii, individuals at NII and NIII were more susceptible to P. donghaiense and K. mikimotoi. Lower egg production rates were also observed when copepods were exposed to P. donghaiense and K. mikimotoi, and hatching success decreased only with exposure to P. donghaiense. These results suggest that blooms of the two common dinoflagellates may have detrimental effects on the survival of nauplii and the reproduction of C. sinicus, which may pose a major threat to the recruitment of C. sinicus.

Beneficial effects of Ectothiorhodospira shaposhnikovii WF on larval cultivation of Litopenaeus vannamei.

To develop high quality probiotics for shrimp larviculture, the effects of a photosynthetic purple sulphur bacterium WF identified as Ectothiorhodospira shaposhnikovii on survival and development of Litopenaeus vannamei larvae were evaluated in vivo. The larvae exhibited a better survival rate after administration of strain WF compared to the probiotic Rhodopseudomonas palustris. To investigate the effect of dose and dosing frequency, strain WF was added to larvae, stages nauplius 6 to zoea 3, at three different doses and dosing frequencies. Larval treatment with strain WF twice at 10(6) cfu/ml exhibited significantly higher survival compared to the other doses and dosing frequencies as well as the control. The effect on water quality was assessed by applying strain WF to larvae, stages nauplius 6 to postlarvae 1, under conditions of zero water exchange and one-third water exchange. The larvae exhibited higher survival and faster growth when treated under conditions of zero water exchange. No significant difference was detected in the levels of three water quality parameters and in vibrio counts between these two conditions. Therefore, E. shaposhnikovii WF acts both as a bioremediation agent and nutrient source and can benefit shrimp larvae if given at an appropriate dose and dosing frequency. Strain WF, a moderate halophile, shows great promise as a water additive in improving water quality and providing nutrition for shrimp larviculture.

Molecular cloning, characterization and expression analysis of the protein arginine N-methyltransferase 1 gene (As-PRMT1) from Artemia sinica

Protein arginine N-methyltransferase 1 (PRMT1) is an important epigenetic regulation factor in eukaryotic genomes. PRMT1 is involved in histone arginine loci methylation modification, changes in eukaryotic genomes' chromatin structure, and gene expression regulation. In the present paper, the full-length 1201-bp cDNA sequence of the PRMT1 homolog of Artemia sinica (As-PRMT1) was cloned for the first time. The putative As-PRMT1 protein comprises 346 amino acids with a SAM domain and a PRMT5 domain. Multiple sequence alignments revealed that the putative sequence of As-PRMT1 protein was relatively conserved across species, especially in the SAM domain. As-PRMT1 is widely expressed during embryo development of A. sinica. This is followed by a dramatic upregulation after diapause termination and then downregulation from the nauplius stage. Furthermore, As-PRMT1 transcripts are highly upregulated under conditions of high salinity and low temperature stress. These findings suggested that As-PRMT1 is a stress-related factor that might promote or inhibit the expression of certain genes, play a critical role in embryonic development and in resistance to low temperature and high salinity stress.

DISTINCTIVE LOCALIZATION OF GROUP 3 LATE EMBRYOGENESIS ABUNDANT SYNTHESIZING CELLS DURING BRINE SHRIMP DEVELOPMENT.

Despite numerous studies on late embryogenesis abundant (LEA) proteins, their functions, roles, and localizations during developmental stages in arthropods remain unknown. LEA proteins protect crucial proteins against osmotic stress during the development and growth of various organisms. Thus, in this study, fluorescence in situ hybridization was used to determine the crucial regions protected against osmotic stress as well as the distinctive localization of group 3 (G3) LEA(+) cells during brine shrimp development. Several cell types were found to synthesize G3 LEA RNA, including neurons, muscular cells, APH-1(+) cells, and renal cells. The G3 LEA(+) neuronal cell bodies outside of the mushroom body projected their axonal bundles to the central body, but those inside the mushroom body projected their axonal bundles toward the deutocerebrum without innervating the central body. The cell bodies inside the mushroom body received axons of the G3 LEA(+) sensory cells at the medial ventral cup of the nauplius eye. Several glands were found to synthesize G3 LEA RNA during the nauplius stages of brine shrimp, including the sinus, antennal I and II, salt, and three ectodermal glands. This study provides the first demonstration of the formation of G3 LEA(+) sinus glands at the emergence stages of brine shrimp. These results suggest that G3 LEA protein is synthesized in several cell types. In particular, specific glands play crucial roles during the emergence and nauplius stages of brine shrimp.

Larval development of the pedunculate barnacles Octolasmis angulata Aurivillius 1894 and Octolasmis cor Aurivillius 1892 (Cirripedia: Thoracica: Poecilasmatidae) from the gills of the mud crab, Scylla tranquebarica Fabricius, 1798

Detailed studies of larval development of Octolasmis angulata and Octolasmis cor are pivotal in understanding the larval morphological evolution as well as enhancing the functional ecology. Six planktotrophic naupliar stages and one non-feeding cyprid stage are documented in details for the first time for the two species of Octolasmis. Morphologically, the larvae of O. angulata and O. cor are similar in body size, setation patterns on the naupliar appendages, labrum, dorsal setae-pores, frontal horns, cyprid carapace, fronto-lateral gland pores, and lattice organs. Numbers of peculiarities were observed on the gnathobases of the antennae and mandible throughout the naupliar life-cycle. The setation pattern on the naupliar appendages are classified based on the segmentation on the naupliar appendages. The nauplius VI of both species undergoes a conspicuous change before metamorphosis into cyprid stage. The cyprid structures begin to form and modify beneath the naupliar body towards the end of stage VI. This study emphasises the importance of the pedunculate barnacle larval developmental studies not only to comprehend the larval morphological evolution but also to fill in the gaps in understanding the modification of the naupliar structures to adapt into the cyprid life-style.

Biochemical composition of the promising live feed tropical calanoid copepod Pseudodiaptomus annandalei (Sewell 1919) cultured in Taiwanese outdoor aquaculture ponds

Abstract The use of copepods as live feed has shown good potential, and in Taiwan copepods are harvested specifically as live feed for fin-fish production. The calanoid copepod Pseudodiaptomus annandalei is a species found typically in Taiwanese aquaculture and in the rest of the Indo-Pacific region. The copepods, as well as seston, were sampled from outdoor large-scale aquaculture ponds in southern Taiwan during a three week period in the summer, and their somatic biomass, fatty acid and amino acid profiles were examined. The resulting fatty acid profiles of the copepods and pond seston were compared. The analyses reveal high contents of fatty acids in the adult females (approx. 16% of dry weight) with moderate content in the nauplii (approx. 5% of dry weight). Relative abundance of HUFAs was also high. The ratio of fatty acids C22:6 n − 3 (DHA) and C20:5 n − 3 (EPA) stayed above 1.4 with the lowest combined relative abundance of 21.8% of total fatty acid content. The fatty acid C20:4 n − 6 (ARA) was present in adult females and late stage nauplii. Overall, P. annandalei demonstrated good trophic transfer capabilities of HUFAs. Discrepancies between adult female and seston fatty acid profiles indicate possible fatty acid chain alteration mechanisms and/or alternative dietary input. Frequent addition of different types of meal and manure by the farmers, in order to stimulate productivity in the ponds, may provide adults with additional fatty acids that are not found in the pond seston. Also, amino acid compositions in adult females and late stage nauplii reveal high abundances of lysine, arginine and histidine, which is a further indication of an intake of alternative particles to phytoplankton. Overall, the amino acid profile of P. annandalei reveals an abundance of essential amino acids above 53.8 ± 1.2%, combined with an estimated protein content of 57% of dry weight for adult females. Both the fatty and amino acid profiles show favourable nutritional values towards fish larvae rearing. Further investigation into P. annandalei's potential biosynthetic capabilities and intake of particles other than pelagic seston could pave the way for further manipulation of its nutritional value to suit a range of species of fish larvae.

Capturing the life history of the marine copepod Calanus sinicus into a generic bioenergetics framework

Quantitative knowledge about copepod life histories is of crucial importance to interpret and predict the impacts of natural and anthropogenic stressors in this taxonomic group. Dynamic Energy Budget (DEB) models are a useful tool in this context, as they quantitatively link the energy taken up by feeding to energy-demanding traits such as growth, development and reproduction. The copepod life cycle, however, has several features that require closer investigation. Firstly, they sport larval development through six naupliar stages (of which the initial stages do not feed), followed by six copepodite stages (which have a different shape from the nauplii). Furthermore, growth stops rather abruptly after the final moult to the adult stage, and many species build up a large lipid storage to survive, and initiate reproduction, in absence of food. After a few modifications, the simple and generic DEBkiss model could be calibrated for Calanus sinicus using data on body composition and size at age for different temperatures. Embryo and naupliar development were well explained by the model, after correcting for their deviating shape from the copepodites. Ceasing of growth after the final moult was implemented as a size-dependent switch in allocation. With these assumptions, predictions could be made for the rates of ingestion, respiration and reproduction in adults. The predictions were consistent with observed rates, which indicates the realism of the model structure and its parameterisation. Several issues remain to be addressed, specifically, the dynamics of lipid storage and its use. However, the present study provides a starting point for applications of DEB theory to copepods.