Academic literature on the topic 'Larval metamorphosis'
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Journal articles on the topic "Larval metamorphosis"
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Pronych, Scott, and Richard Wassersug. "Lung use and development in Xenopus laevis tadpoles." Canadian Journal of Zoology 72, no. 4 (April 1, 1994): 738–43. http://dx.doi.org/10.1139/z94-099.
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Shortly after hatching, Xenopus laevis tadpoles fill their lungs with air. We examined the role played by early lung use in these organisms, since they are able to respire with both their lungs and their gills. We investigated the effect on X. laevis development when the larvae were prevented from inflating their lungs, and whether early lung use influenced the size of the lungs or the tadpole's ability to metamorphose. Tadpoles that were denied access to air had lungs one-half the size of those of controls. This difference in lung size was too large to be explained merely by a stretching of the lung due to inflation. The longer tadpoles were denied access to air, the longer they took to metamorphose, and their probability of completing metamorphosis diminished. One tadpole raised throughout its larval life without access to air successfully metamorphosed but had abnormal, solidified lungs and an enlarged heart. Collectively, these experiments demonstrate that early lung use in tadpoles is important in determining both ultimate lung size and the probability of successfully metamorphosing. Lung use during early larval development in X. laevis is not absolutely necessary for survival through metamorphosis, but its absence severely handicaps growth.
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Youson, J. H., J. A. Holmes, J. A. Guchardi, J. G. Seelye, R. E. Beaver, J. E. Gersmehl, S. A. Sower, and F. W. H. Beamish. "Importance of Condition Factor and the Influence of Water Temperature and Photoperiod on Metamorphosis of Sea Lamprey Petromyzon marinus." Canadian Journal of Fisheries and Aquatic Sciences 50, no. 11 (November 1, 1993): 2448–56. http://dx.doi.org/10.1139/f93-269.
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The incidence of metamorphosis of larval sea lamprey, Petromyzon marinus, was strongly affected by water temperature but not photoperiod. In a 1991 experiment, the development of metamorphosing animals in 13 °C water was retarded about 1 mo relative to animals metamorphosing at 21 °C and to a population from the Chippewa River, Michigan; the minimum length, weight, and condition factor (CF) of metamorphosing experimental animals were 117 mm, 2.8 g, and 1.50, respectively, and only 4% metamorphosed at 13 °C and 18.9% at 21 °C. In 1992, with a population from the Great Chazy River, New York, 66% of the animals at 13 °C and 84% at 21 °C metamorphosed. The higher incidence of metamorphosis in 1992 is partly related to the use of larvae that were larger than the minima established in 1991. We predicted, using criteria defined below, that 74 and 72% of the animals at 13 and 21 °C, respectively, would metamorphose. Our predictions were consistent with observations at 13 °C and for five of seven replicate tanks at 21 °C. We suggest that a presumptive metamorphosing sea lamprey in landlocked populations should be at least 120 mm long, weigh 3.0 g, and have a CF ≥ 1.50 and that these criteria must be used in conjunction.
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Eri, R., J. M. Arnold, V. F. Hinman, K. M. Green, M. K. Jones, B. M. Degnan, and M. F. Lavin. "Hemps, a novel EGF-like protein, plays a central role in ascidian metamorphosis." Development 126, no. 24 (December 15, 1999): 5809–18. http://dx.doi.org/10.1242/dev.126.24.5809.
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All chordates share several characteristic features including a dorsal hollow neural tube, a notochord, a pharynx and an endostyle. Unlike other chordate taxa, ascidians have a biphasic life-history with two distinct body plans. During metamorphosis, the larval nerve cord and notochord degenerate and the pharyngeal gill slits and endostyle form. While ascidians, like other marine invertebrates, metamorphose in response to specific environmental cues, it remains unclear how these cues trigger metamorphosis. We have identified a novel gene (Hemps) which encodes a protein with a putative secretion signal sequence and four epidermal growth factor (EGF)-like repeats which is a key regulator of metamorphosis in the ascidian Herdmania curvata. Expression of Hemps increases markedly when the swimming tadpole larva becomes competent to undergo metamorphosis and then during the first 24 hours of metamorphosis. The Hemps protein is localised to the larval papillae and anterior epidermis of the larva in the region known to be required for metamorphosis. When the larva contacts an inductive cue the protein is released, spreading posteriorly and into the tunic as metamorphosis progresses. Metamorphosis is blocked by incubating larvae in anti-Hemps antibodies prior to the addition of the cue. Addition of recombinant Hemps protein to competent larvae induces metamorphosis in a concentration-dependent manner. A subgroup of genes are specifically induced during this process. These results demonstrate that the Hemps protein is a key regulator of ascidian metamorphosis and is distinct from previously described inducers of this process in terrestrial arthropods and aquatic vertebrates.
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McWilliam, Paulette S., and Bruce F. Phillips. "Metamorphosis of the final phyllosoma and secondary lecithotrophy in the puerulus of Panulirus cygnus George: a review." Marine and Freshwater Research 48, no. 8 (1997): 783. http://dx.doi.org/10.1071/mf97159.
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The final phyllosoma of Panulirus cygnus metamorphoses to a non-feeding puerulus that lives on energy reserves accumulated in the final larva, and the metamorphic moult occurs mainly in the slope region adjoining the shelf-break off Western Australia. A review of the literature on field studies, laboratory rearing and nutritional studies of phyllosomal and other decapod zoeal larvae provided no evidence that metamorphosis in P. cygnus (or other shallow-water palinurids) is triggered by a direct environmental cue. It did indicate that metamorphosis results from the culmination of sustained nutrition and reserve energy levels through the later larval phase. Therefore, since the puerulus is secondarily lecithotrophic, it is considered that metamorphosis occurs only after the final phyllosoma has reached some critical, specific, level of stored energy reserves. Appropriate food for later larval development and successful metamorphosis of P. cygnus is more abundant in the shelf-break region (than further offshore) because this is a region of high plankton and micronekton biomass dominated by the Leeuwin Current. It also explains why metamorphosis occurs mainly in the shelf-break region. This review indicates research necessary for evaluation of the present interpretation and of larval recruitment processes in this species.
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Rahman, M. Aminur, Fatimah Md Yusoff, A. Arshad, and Tsuyoshi Uehara. "Effects of Delayed Metamorphosis on Larval Survival, Metamorphosis, and Juvenile Performance of Four Closely Related Species of Tropical Sea Urchins (GenusEchinometra)." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/918028.
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We report here, the effects of extended competency on larval survival, metamorphosis, and postlarval juvenile growth of four closely related species of tropical sea urchins,Echinometrasp. A (Ea),E. mathaei(Em),Echinometrasp. C (Ec), andE. oblonga(Eo). Planktotrophic larvae of all four species fed on cultured phytoplankton (Chaetoceros gracilis) attained metamorphic competence within 22–24 days after fertilization. Competent larvae were forced to delay metamorphosis for up to 5 months by preventing them from settling in culture bottles with continuous stirring on a set of 10 rpm rotating rollers and larval survival per monthly intervals was recorded. Larval survival was highest at 24 days, when competence was attained (0 delayed period), and there were no significant differences among the four species. Larvae that had experienced a prolonged delay had reduced survival rate, metamorphosis success, and juvenile survival, but among older larvae, Em had the highest success followed by Ea, Eo, and Ec. Juveniles from larvae of all four species that metamorphosed soon after becoming competent tended to have higher growth rates (test diameter and length of spines) than juveniles from larvae that metamorphosed after a prolonged period of competence with progressively slower growth the longer the prolonged period. Despite the adverse effects of delaying metamorphosis on growth parameters, competent larvae of all four species were able to survive up to 5 months and after metamorphosis grew into 1-month-old juveniles in lab condition. Overall, delayed larvae of Em showed significantly higher larval survival, metamorphosis, and juvenile survival than Ea and Eo, while Ec showed the lowest values in these performances. Em has the most widespread distribution of these species ranging from Africa to Hawaii, while Ec probably has the most restricted distribution. Consequently, differences in distribution may be related to differences in the ability to delay metamorphosis.
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Chambers, R. Christopher, and William C. Leggett. "Size and Age at Metamorphosis in Marine Fishes: An Analysis of Laboratory-Reared Winter Flounder (Pseudopleutonectes americanus) with a Review of Variation in Other Species." Canadian Journal of Fisheries and Aquatic Sciences 44, no. 11 (November 1, 1987): 1936–47. http://dx.doi.org/10.1139/f87-238.
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Offspring of adult winter flounder (Pseudopleuronectes americanus) collected from Conception Bay, Newfoundland, were reared from fertilization to metamorphosis. We tested two hypotheses: 1) length and age at metamorphosis are equally variable among individuals and (2) length and age at metamorphosis are not correlated. Length at metamorphosis was significantly less variable than age at metamorphosis when data from all laboratory populations were pooled and in 15 of 18 populations. Coefficients of variation for length and age at metamorphosis for the pooled data were 0.051 and 0.123, respectively. Length and age at metamorphosis were positively correlated when the data were pooled (r = 0.42, p < 0.001) and within 8 of 18 populations. Larvae that metamorphose late do so at larger sizes. When length and age at metamorphosis were converted to growth and developmental rates for the full larval period, significant positive correlations were evident between these rates for the pooled data (r = 0.68, p < 0.001) and within 16 of 18 populations. Larvae that grow slowly, therefore, remain as larvae longer. An examination of published values on size and age at metamorphosis in marine fishes revealed a pattern consistent with our findings both within and among populations and environments: (1) variation in length was less than variation in age at metamorphosis and (2) positive correlations between growth and developmental rates were evident through the larval period. Increased size at metamorphosis may ameliorate competitive effects and reduce the risk of predation in the period immediately following metamorphosis. Due to the considerable variation in the duration of the larval period (age at metamorphosis) the number of individuals that successfully metamorphose and subsequently enter the mature population could be significantly altered under differing environmental conditions.
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Pawlik, Joseph R. "Larval settlement and metamorphosis of two gregarious sabellariid polychaetes:Sabellaria alveolatacompared withPhragmatopoma californica." Journal of the Marine Biological Association of the United Kingdom 68, no. 1 (February 1988): 101–24. http://dx.doi.org/10.1017/s002531540005013x.
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Two sabellariid polychaetes,Sabellaria alveolatafrom European waters andPhragmatopoma californicafrom the west coast of North America, are known from previous work to have larvae that settle and metamorphose preferentially on the cemented sand tubes of conspecific adults. The naturally occurring inducers of larval metamorphosis were recently isolated and identified forP. californica.In the present study, larval behaviour ofS. alveolataandP. californicawas compared in reciprocal laboratory settlement assays. For both species, metamorphosis occurred to a greater extent on conspecific tube sand than on control sand or on heterospecific tube sand. Extraction of the tube sand ofS. alveolatawith organic solvents diminished its capacity to induce metamorphosis pi conspecific larvae, but this capacity was not transferred to the extracts, as was the case forP. californica. The substance responsible for the enhanced metamorphosis ofS. alveolataon conspecific tube sand remains unknown. The free fatty acid (FFA) inducers of larval metamorphosis ofP. californicaeither inhibited, or had no effect on, metamorphosis ofS. alveolata. Both species responded abnormally upon exposure to unnaturally high concentrations of certain (particularly polyenoic) FFAs. Abnormal larval responses ofS. alveolata, however, did not incorporate behavioural components of normal metamorphosis, as were observed forP. californica. FFAs were isolated from the natural tube sand ofS. alveolataat less than one-tenth the concentration found in the natural tube sand ofP. californica. The differences between the two species provide further evidence that a very specific mechanism is responsible for the perception of FFAs by the larvae ofP. californica.
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Holmes, John A., and John H. Youson. "Fall condition factor and temperature influence the incidence of metamorphosis in sea lampreys, Petromyzon marinus." Canadian Journal of Zoology 72, no. 6 (June 1, 1994): 1134–40. http://dx.doi.org/10.1139/z94-151.
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Larval sea lampreys of immediate premetamorphic size (at least 120 mm and 3.0 g) were subjected to ambient or constant 21 °C temperature regimes for 9 months to investigate the influence of temperature and a fall condition factor (CF) of 1.50 or greater on the incidence of metamorphosis the following summer. The incidence of metamorphosis was 53% in the ambient temperature regime (29/55) and only 2% (1/55) in the constant temperature regime. About 64% (7/11) of the presumptively metamorphic larvae in the ambient temperature regime entered metamorphosis compared with 10% (1/10) in the constant temperature regime. Our predictions of metamorphosis based on CF were consistent with the observation that seven presumptively metamorphic larvae (CF ≥ 1.50) metamorphosed in the ambient temperature regime and that there was no metamorphosis among presumptively nonmetamorphic larvae in the constant temperature regime. Significantly more presumptively nonmetamorphic larvae in the ambient regime entered metamorphosis and fewer presumptively metamorphic larvae (CF < 1.50) metamorphosed in the constant temperature regime than expected. We attribute this response to the effects of temperature on metabolic processes. Larval sea lampreys of the appropriate size (≥ 120 mm and ≥ 3.0 g) with a CF of 1.50 or greater in the fall will usually enter metamorphosis the following July, but the accuracy of these predictions may be improved in some populations by using an empirically determined CF criterion that reflects seasonal or population differences in mass–length relationships.
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Licht, Lawrence E. "The effect of food level on growth rate and frequency of metamorphosis and paedomorphosis in Ambystoma gracile." Canadian Journal of Zoology 70, no. 1 (January 1, 1992): 87–93. http://dx.doi.org/10.1139/z92-013.
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The effect of food level on larval growth response and frequency of metamorphosis and paedomorphosis was examined in Ambystoma gracile from high- and low-elevation populations in British Columbia. Larvae that eventually metamorphosed and those that became paedomorphic did not differ in growth rates when fed equal quantities of food. Body size at metamorphosis did not differ between fast- and slow-growing larvae, but larvae fed high levels of food metamorphosed sooner than those fed less. Food level had no effect on the frequency of metamorphosis and paedomorphosis. Larvae of different sexes did not differ in growth rate or frequency of metamorphosis and paedomorphosis, nor did larvae originating from populations from high and low elevations. Variation in the metamorphic response occurred within and between larvae from separate egg clutches. The findings are discussed in light of current hypotheses on factors influencing alternative life-history patterns in facultatively paedomorphic salamanders.
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Holmes, John A., Helen Chu, Syeda A. Khanam, Richard G. Manzon, and John H. Youson. "Spontaneous and induced metamorphosis in the American brook lamprey, Lampetra appendix." Canadian Journal of Zoology 77, no. 6 (October 10, 1999): 959–71. http://dx.doi.org/10.1139/z99-056.
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We described the seven stages of spontaneous metamorphosis in the American brook lamprey (Lampetra appendix) and assessed the importance of size as a determinant of spontaneous and induced metamorphosis. Serum concentrations of the thyroid hormones (TH) thyroxine (T4) and triiodothyronine (T3) were measured in metamorphosing and nonmetamorphosing L. appendix. The sequence of stages in metamorphosis and changes in the relative lengths of most body regions were consistent with data reported for other lamprey species. However, premetamorphic and metamorphosing L. appendix in the early stages of metamorphosis (1-3) were much larger in size (at least 155 mm and 5.40 g) than has been observed for other lamprey species. Serum concentrations of T4 and T3 were high by the end of the larval period and declined significantly by stage 2 of metamorphosis. Larvae greater than or equal to 130 mm in length were treated with either potassium perchlorate (KClO4; 0.01 and 0.05%) or 10 mg/L propylthiouracil (PTU; 0.0001%) for 117 days from September to January to determine if metamorphosis could be induced by these goitrogens. Both concentrations of KClO4 successfully induced metamorphosis in L. appendix, but the incidence of metamorphosis (62%) was much lower than reported in sea lampreys (98%) of comparable size. Serum concentrations of T4 and T3 declined by 64-76 and 93-96% relative to control values, respectively, in metamorphosing and nonmetamorphosing L. appendix treated with KClO4. PTU elicited declines of 55% for T4 and 80% for T3, but only one animal metamorphosed. Based on these data, we conclude that a decline in serum TH levels is necessary for metamorphosis in L. appendix, but not sufficient by itself to trigger the process.
Dissertations / Theses on the topic "Larval metamorphosis"
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Besson, Marc. "Importance of metamorphosis in coral-reef fish larval recruitment facing anthropogenic pressures." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEP024/document.
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Le maintien et le renouvellement des populations de poissons coralliens dépendent en grande partie du recrutement larvaire, c’est-à-dire de l’installation des larves pélagiques dans les habitats récifaux adultes, et de leur survie après s’être métamorphosées en juvéniles. De plus en plus d’études révèlent que les changements de composition de l’eau, causés par le changement climatique et la pollution, peuvent altérer les capacités sensorielles des poissons coralliens, diminuant leurs aptitudes à localiser des habitats propices (maximisant leur croissance et diminuant leur mortalité) lors de l’installation. Cependant, les mécanismes internes à l’origine de ces phénomènes sont méconnus. Lors de cette thèse, j’ai examiné le recrutement larvaire du poisson chirurgien bagnard Acanthurus triostegus et mis en évidence que les changements écologiques, morphologiques, physiologiques et comportementaux qui s’y déroulent correspondent à une métamorphose contrôlée par les hormones thyroïdiennes (HT). J’ai ensuite analysé comment des stress d’origine anthropique, tels que l’élévation des températures de surface et la pollution par un pesticide d’origine agricole, peuvent perturber sa métamorphose. Lors de cette étape clé de leur cycle de vie, ces perturbations diminuent les taux d’HT, altérant la maturation de leurs organes sensoriels, leurs capacités sensorielles, et augmentant leur mortalité. Cette thèse est donc une analyse holistique de l’impact des perturbations anthropiques sur les processus moléculaires, et les changements histologiques, anatomiques et comportementaux du recrutement larvaire des poissons coralliens. Elle souligne l’importance du système thyroïdien, et invite à une meilleure compréhension des processus endocriniens du recrutement larvaire, dans l’optique d’une amélioration de la conservation des récifs coralliensThe persistence and sustainability of coral-reef fish populations depends on the continued larval recruitment, i.e. successful settlement by pelagic larvae into adult reef habitats and post-settlement survival through metamorphosis to a juvenile stage. There is growing evidence that changes to water conditions due to global change and waterborne pollution can impair coral-reef fish sensory abilities to locate settlement habitats that maximize growth while minimizing mortality risk. However, the inner mechanisms of such impairments remain unknown. In this thesis, I have examined the recruitment phase of the convict surgeonfish Acanthurus triostegus, and determined that the ecological, morphological, physiological and behavioral changes occurring at recruitment correspond to a metamorphosis mediated by thyroid hormones (TH). Then, I investigated whether this metamorphosis is prone to endocrine disruption under anthropogenic disturbances such as elevated sea water temperature and agricultural pesticide pollution. I demonstrated that such pressures can reduce TH levels at a critical developmental stage in coral-reef fishes, impairing their metamorphic processes such as intestine remodeling, sensory organ maturation, and sensory abilities acquisition, further increasing their mortality rates. Overall, this thesis is a holistic analysis that addresses molecular, histological, anatomical, and behavioral assays of multiple stressors affecting coral-reef fish recruitment. It indicates the importance of a proper endocrine function during coral-reef fish recruitment, highlighting the need for a better understanding of these processes for coral-reef conservation
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Martin, Damali Nzinga. "Cell changes during autophagic cell death of larval salivary glands during Drosophila melanogaster metamorphosis." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1710.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Cell Biology & Molecular Genetics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Walsh, Patrick Thomas. "The plasticity of life histories during larval development and metamorphosis, using amphibians as study organisms." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/183/.
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The ability of animals to vary growth, development rate and behaviour in response to environmental conditions has been well documented, particularly during the larval phase in animals with complex life cycles. The evolution and maintenance of plasticity in response to environmental conditions is likely to be adaptive in animals that face unpredictable environments. However, there are two aspects of life histories in animals with complex life cycles, which would be expected to favour plasticity, that have received limited attention: traits during metamorphic climax and variation in the life history phase at which temperate species spend the winter. Therefore the aims of this thesis were to consider the environmental factors that are likely to result in plasticity in the timing and duration of metamorphic climax and contribute to variation in the over-wintering life stage, using amphibians as study animals. To assess the ability of animals to respond to environmental conditions during metamorphic climax conditions were manipulated during metamorphosis independent of larval treatment. Accordingly all larvae entered metamorphic climax having experienced the same conditions. The African clawed toad, Xenopus laevis, was used. I examined the influence of environmental temperature, predation risk and starting body size on several traits during the transitional stage (e.g. mass, snout-vent length (SVL), head width, tail morphology, duration and locomotor performance). Morphological measures and the duration of the life stage were shown to vary with temperature and predation risk. As predicted, higher temperatures and the risk of predation resulted in faster development through metamorphosis and smaller sizes on completion. The acceleration of metamorphosis was demonstrated to have potential costs, not in the form of reduced locomotor performance as predicted, but in a reduction in juvenile size as a result of faster metamorphic development. This suggests that, during this potentially vulnerable stage, it would be advantageous to take more time to complete in the absence of predators. Greater body size at the onset of metamorphosis requires a longer time to complete metamorphic climax suggesting that having a greater quantity of tissue to reconfigure during metamorphosis takes more time. Therefore, the conditions experienced during metamorphosis may have important implications for juvenile fitness and should be considered in studies of life history plasticity. In many temperate species with complex life cycles, the life history stage at which a species can survive the winter is generally fixed, imposing time limits on the timing of development. Most of these species must therefore often modify developmental rate to reach the appropriate stage or size at the onset of winter, usually at a cost to other traits. However, variation in the stage or developmental group that some amphibian, fish and insect species spend the winter has been observed, such as in the common frog Rana temporaria in the UK, which can spend the first winter as either a tadpole or as a juvenile frog. To investigate the factors that contribute to this variation in life history, I examined the influence of environmental temperature, food availability and water depth on the rate of larval development and growth. Data on development, growth and environmental temperature of a field population of R. temporaria, which have been observed to over-winter as larvae, were collected to determine how and when the two divergent early life history patterns of development were established. Development rate was slowed by reduced temperatures and food availability and greater water depth during rearing. Temperature and food availability also had a significant impact on the proportion of larvae that over-wintered, but in the field other factors are likely to contribute to the within-population variation in wintering strategy. While a greater water depth did prolong larval development, as predicted, this does not appear to be due to the cost of surfacing to respire acting as a constraint on development, since a similar slowing in development was observed in the lung-less Bufo bufo tadpoles. The results of these studies did not allow a definitive assessment of whether over-wintering as larvae represents an adaptive strategy or occurs as the result of developmental constraints. There is some evidence that over-wintering as larvae might be adaptive, since on completion of metamorphosis individuals that wintered as larvae were larger than those that completed metamorphosis late in the summer. Further work is necessary to identify other factors contributing to the over-wintering of larvae in Rana temporaria and to determine the adaptive significance, if any, of the alternative life history patterns.
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Boley, Meredith A. "A COMPARATIVE STUDY OF LARVAL GENE EXPRESSION BETWEEN A PAEDOMORPHIC AND METAMORPHIC SPECIES OF AMBYSTOMATID SALAMANDER." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_theses/585.
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Ambystoma tigrinum undergoes an obligatory metamorphosis while A. mexicanum fails to metamorphose and exhibits paedomorphosis. While it is clear that salamander paedomorphosis is associated with genetic changes that delay developmental timing, it is not clear when and how these changes manifest during development. It is possible that paedomorphic and metamorphic larvae show equivalent patterns of developmental until late in the larval period, when brain regions become competent to stimulate the release of metamorphic hormones. To test this hypothesis, I compared gene expression patterns between the brains of A. mexicanum and A. t. tigrinum larvae. In support of the developmental equivalence hypothesis, 114 differentially expressed genes (DEGs) were identified in common between the species and all but 2 showed the same temporal pattern of expression. However, more DEGs were identified uniquely from each species. In particular, several genes that are associated with the hypothalamus-pituitaryinterrenal axis, which is implicated in metamorphic regulation in amphibians, exhibited significant expression differences between A. mexicanum and A. t. tigrinum larvae. The results show that metamorphic and paedomorphic modes of development are associated with different transcriptional programs in the brain and these programs diverge during early larval development.
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Luizi, Frederic. "Larval development and metamorphosis in Atlantic halibut (Hippoglossus hippoglossus) : influences of nutritional, environmental and physiological factors." Thesis, University of Stirling, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311703.
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Lafuente, Isabel. "Reproduction, larval growth and metamorphosis of the nudibranch molluscs, Onchidoris bilamellata (L.) and Goniodoris nodosa (Montagu)." Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/14641.
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This study investigated the reproduction, larval growth and metamorphosis of the nudibranchs Onchidoris bilamellata (L.) and Goniodoris nodosa (Montagu) under controlled laboratory conditions. In addition, the rare occurrence of spawning events of O. bilamellata taking place in the field outwith the winter and spring reproductive period was studied. Onchidoris bilamellata and Goniodoris nodosa differ in the size and number of eggs produced per spawning event. In the present study O. bilamellata does not exhibit a clear spawning pattern, whereas G. nodosa lays increasingly smaller eggs and larvae as the season progresses. The diameter of the eggs of O. bilamellata is not correlated with the organic content per egg. The data available for G. nodosa were insufficient to analyse this relationship. The rates of larval growth and development are reported for Onchidoris bilamellata and Goniodoris nodosa. These variables do not differ significantly for O. bilamellata between cultures maintained under various light regimes, ranging from continuous darkness to continuous illumination, and are comparable to those of G. nodosa. The shell growth pattern exhibited by larvae of G. nodosa is sigmoid, similar to that of other opisthobranchs. Spawn masses laid during the winter and spring months were collected fresh from the field and compared to spawn masses collected from the field in July and September, outwith the typical spawning period of Onchidoris bilamellata in the British Isles. The shell size of the July and September hatchlings was significantly smaller than that of the winter and spring hatchlings. Furthermore, the larvae hatched from spawn masses laid in September cultured in the laboratory exhibited high mortality rates and the overwhelming majority did not survive through metamorphosis. The significance of the spawning activity of O. bilamellata past the typical spawning period of this species is discussed. The induction of metamorphosis of Onchidoris bilamellata was investigated using seawater containing elevated concentrations of potassium ion, and the results indicate that the optimal concentration inductive of metamorphosis is 19 mM K+ ASW, Metamorphosis experiments were also performed with the natural prey of O. bilamellata, the acorn barnacle Semibalanus balanoides (L.). The results suggest that pediveligers can be induced to metamorphose at a distance from the inductive substrata. Attempts were made to identify the natural inductive cue of Goniodoris nodosa, but this was not successful.
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Fulmore, Helena Sasha. "Desperate Coral Larvae? Behavioral Responses to Settlement Cues in Aging Agaricia agaricites Larvae." Thesis, NSUWorks, 2019. https://nsuworks.nova.edu/occ_stuetd/519.
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The global stressors of ocean warming and acidification, as well as local stressors such as eutrophication, overfishing, and coastal construction, have all contributed to the severe decline in coral populations worldwide. Recovery of coral reefs depends partly on recruitment, which relies on the response of larvae to settlement cues indicative of habitat quality; however, it remains unclear whether recruitment in disturbed areas will be compromised. Specifically, as reefs become more disturbed and dominated by macroalgae, it is important to understand larval behavior in response to changes in habitat quality. In this study, we first assessed the settlement success of newly released Agaricia agariciteslarvae in response to several settlement cues, including temperature and water movement. Then, to test the Desperate Larva Hypothesis, the ability of larvae of different ages (0-7 days) to settle and discriminate between inducing and inhibitory settlement cues was assessed. Newly released larvae displayed a stronger preference for settling on crustose coralline algae (93%) than on ceramic plates in macroalgae- (30%) or conspecific-treated seawater (5%), or filtered seawater (13%) (control). Older larvae became progressively less discriminatory of settlement cues, settling even in response to inhibitory cues. This confirms that, although the absence of good settlement cues initially deters settlement, larvae become desperate as they become older and settle even on unfavorable substrates, thus contributing to recruitment in poor quality habitats.
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Li, Honglei. "Investigation of genes involved in larval attachment and metamorphosis of biofouling species hydroides elegans and balanus amphitrite /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?AMCE%202007%20LI.
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Hollar, Amy Rebecca. "Cloning and developmental expression of thyroid hormone receptors from three species of spadefoot toads with divergent larval period durations." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1291050160.
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Wacker, Alexander, and Eric von Elert. "Strong influences of larval diet history on subsequent post-settlement growth in the freshwater mollusc Dreissena polymorpha." Universität Potsdam, 2002. http://opus.kobv.de/ubp/volltexte/2008/1762/.
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Significant seasonal variation in size at settlement has been observed in newly settled larvae of Dreissena polymorpha in Lake Constance. Diet quality, which varies temporally and spatially in freshwater habitats, has been suggested as a significant factor influencing life history and development of freshwater
invertebrates. Accordingly, experiments were conducted with field-collected larvae to test the hypothesis that diet quality can determine planktonic larval growth rates, size at settlement and subsequent post-metamorphic growth
rates. Larvae were fed one of two diets or starved. One diet was composed of cyanobacterial cells which are deficient in polyunsaturated fatty acids (PUFAs), and the other was a mixed diet rich in PUFAs. Freshly metamorphosed animals from the starvation treatment had a carbon content per individual 70% lower than that of larvae fed the mixed diet. This apparent exhaustion of larval internal reserves resulted in a 50% reduction of the postmetamorphic growth rates. Growth was also reduced in animals previously fed the cyanobacterial diet.
Hence, low food quantity or low food quality during the larval stage of D. polymorpha lead to irreversible effects for postmetamorphic animals, and is related to inferior competitive abilities.
Books on the topic "Larval metamorphosis"
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The mystery of metamorphosis: A scientific detective story. White River Junction, Vt: Chelsea Green Pub., 2011.
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Costa, Cleide, Sergio Ide, and Carlos Estevão Simonka. Insetos imaturos: Metamorfose e identificação. Ribeirão Preto: Holos Editora, 2006.
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Wilkenfeld, Joshua S. Survival, metamorphosis and growth of penaeid shrimp larvae reared on a variety of algal and animal foods. College Station, Tex: Sea Grant College Program, Texas A & M University, 1985.
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Carrier, Tyler J., Adam M. Reitzel, and Andreas Heyland, eds. Section 3 Summary—Larval Transport, Settlement, and Metamorphosis. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786962.003.0015.
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Life cycles for broadcast-spawning marine invertebrates are characterized by a pelagic (larval) and benthic (juvenile and adult) stage, which are differentiated by the process of settlement and metamorphosis. While settlement and recruitment are concepts that primarily deal with the ecological aspects of this transition, they are often accompanied by a drastic morphological and developmental transition. Larval transport, the means of reaching suitable settlement sites, is difficult to study, but insights from genetics, behavior, sensory ecology, and oceanography have provided important insights....
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Pernet, Bruno, ed. Larval Feeding: Mechanisms, Rates, and Performance in Nature. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786962.003.0007.
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Larvae of many marine invertebrates must capture and ingest particulate food in order to develop to metamorphosis. These larvae use only a few physical processes to capture particles, but implement these processes using diverse morphologies and behaviors. Detailed understanding of larval feeding mechanism permits investigators to make predictions about feeding performance, including the size spectrum of particles larvae can capture and the rates at which they can capture them. In nature, larvae are immersed in complex mixtures of edible particles of varying size, density, flavor, and nutritional quality, as well as many particles that are too large to ingest. Concentrations of all of these components vary on fine temporal and spatial scales. Mechanistic models linking larval feeding mechanism to performance can be combined with data on food availability in nature and integrated into broader bioenergetics models to yield increased understanding of the biology of larvae in complex natural habitats.
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Carrier, Tyler J., Adam M. Reitzel, and Andreas Heyland, eds. Section 1 Summary—Evolutionary Origins and Transitions in Developmental Mode. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786962.003.0006.
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Abiotic variables and biotic interactions can act on variation in life history traits, ultimately leading to divergence in reproductive mode. Marine invertebrates have a remarkable diversity in such strategies, sometimes even between closely related species. It is this natural diversity that lends itself to employing a powerful comparative approach, both for particular morphological characteristics as well as molecular signatures from developmental genes. For example, complex life histories, where a larval stage is interposed between the embryo and juvenile, likely represent the product of numerous selection pressures, historical and current, that have shaped the diversity of larval stages in extant marine species. In fact, the very question about “what is a larva?” has to be addressed, as it is so intimately connected to bentho-planktonic life cycle and metamorphosis. Furthermore, novel larval types have evolved in particular lineages and larvae have been secondarily lost in others. This in itself creates an interesting and exciting playground to test evolutionary developmental hypotheses....
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The influence of an insect growth regulator on the larval development of the mud crab Rhithropanopeus harrisii. [Washington, D.C.?: Environmental Protection Agency, 1994.
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Pechenik, Jan A., ed. Latent Effects: Surprising Consequences of Embryonic and Larval Experience on Life after Metamorphosis. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786962.003.0014.
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The coming years will apparently bring increases in seawater temperatures, salinity fluctuation, and ocean acidity, along with increasing pollution levels and increasing incidences of coastal hypoxic events. We can also expect to see shifting patterns of phytoplankton abundance and nutritional quality. Many such stresses experienced early in development—even among brooded embryos—have been found to influence growth rates, survival, and other fitness characteristics following metamorphosis, sometimes for months, both in laboratory studies and in those in which juveniles were transplanted to the field. The effects are usually negative, but have been seemingly positive in a few studies. Vulnerability can vary among species, and even among the offspring from different parents. The mechanisms through which such “latent effects” are mediated are unclear: energy-balance issues and epigenetic factors—in which gene expression patterns are altered without any changes in DNA sequences—seem to be involved.
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Rice, Timothy Matthew. The effects of food deprivation, cold temperatures, and metamorphosis on the accumulation and distribution of lead in larval bullfrogs (Rana catesbeiana). 1998.
Find full textBook chapters on the topic "Larval metamorphosis"
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Kutikova, L. A. "Larval metamorphosis in sessile rotifers." In Rotifera VII, 133–38. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-1583-1_18.
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Pine, Matthew K., Andrew G. Jeffs, and Craig A. Radford. "Effects of Underwater Turbine Noise on Crab Larval Metamorphosis." In The Effects of Noise on Aquatic Life II, 847–52. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-2981-8_104.
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Suzuki, Shintaro. "Induction of Metamorphosis and Thyroid Function in the Larval Lamprey." In Frontiers in Thyroidology, 667–70. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4684-5260-0_121.
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Ito, S., and H. Kitamura. "Induction of larval metamorphosis in the sea cucumber Stichopus japonicus by periphitic diatoms." In Live Food in Aquaculture, 281–84. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-017-2097-7_44.
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Tsukamoto, Sachiko, Haruko Kato, Hiroshi Hirota, and Nobuhiro Fusetani. "Lumichrome Is a Putative Intrinsic Substance Inducing Larval Metamorphosis in the Ascidian Halocynthia roretzi." In The Biology of Ascidians, 335–40. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66982-1_52.
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Williamson, Donald I. "Echinoderms: Metamorphosis." In LARVAE and EVOLUTION, 60–79. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-015-8077-9_7.
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Pires, Anthony. "Artificial Seawater Culture of the Gastropod Crepidula fornicata for Studies of Larval Settlement and Metamorphosis." In Methods in Molecular Biology, 35–44. Totowa, NJ: Humana Press, 2014. http://dx.doi.org/10.1007/978-1-62703-974-1_3.
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Williamson, Donald I. "Echinoderms: Metamorphosis." In The Origins of Larvae, 123–37. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0357-4_10.
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Dhang, Partho, Philip Koehler, Roberto Pereira, and Daniel D. Dye, II. "Ants." In Key questions in urban pest management: a study and revision guide, 77–84. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781800620179.0010.
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Abstract This book chapter discusses ants. Because ants live in large nests that can house many thousands to millions of individuals, their collective effect is certainly what causes greatest concern as a force that may destroy or consume large quantities of food or other materials important to humans. In nature, ants perform beneficial functions, preying on pests, aerating soils, moving soil nutrients, and decomposing organic matter, but in urban environments, they can be considered as one of the most destructive urban pests. Ants belong to the order Hymenoptera which also includes bees and wasps, and, like many other hymenopterans, they are social insects with colony duties divided among different castes. Although most ants can bite with their jaws, the ones that cause greater concern are the ones that sting, using a modified ovipositor to inflict pain. Emphasis should be on excluding ants from buildings and eliminating food and water sources. Ants undergo complete metamorphosis, having egg, larval, pupal, and adult stages. Ant management requires diligent effort and the combined use of mechanical, cultural, sanitation, and chemical methods of control.
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Dawson, Heather A., Bernardo R. Quintella, Pedro R. Almeida, Andrew J. Treble, and Jeffrey C. Jolley. "The Ecology of Larval and Metamorphosing Lampreys." In Lampreys: Biology, Conservation and Control, 75–137. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9306-3_3.
Full textReports on the topic "Larval metamorphosis"
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Koven, William, Gordon Grau, Benny Ron, and Tetsuya Hirano. Improving fry quality, survival and growth in commercially farmed fish by dietary stimulation of thyroid hormone production in premetamorphosing larvae. United States Department of Agriculture, 2004. http://dx.doi.org/10.32747/2004.7695856.bard.
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There is a direct correlation between successful metamorphosis from larvae to post-larvae and the quality of the resultant juveniles or fry. Juvenile quality, in turn, is a major factor influencing fish production level and market price. However, following the profound morphological and physiological changes occurring during metamorphosis, the emerging juveniles in some species characteristically demonstrate heterotrophic growth, poor pigmentation, cannibalism and generally poor survival. The white grouper (Epinephelus aeneus) in Israel and the Pacific threadfin (Polydactylussexfilis) in Hawaii are two promising candidates for mariculture that have high market value but a natural fishery that has sharply declined in recent years. Unfortunately, their potential for culture is severely hampered by variable metamorphic success limiting their production. The main objective was to compare the efficacy and economic viability of dietary or environmental iodine on metamorphic success and juvenile quality in the white grouper and the pink snapper which would lead to improved commercial rearing protocols and increased production of these species both in Israel and the US. The Hawaii Institute of Marine Biology encountered problems with the availability of pink snapper brood stock and larvae and changed to Pacific threadfin or moi which is rapidly becoming a premier aquaculture species in Hawaii and throughout the Indo-Pacific. The white grouper brood stock at the National Center for Mariculture was lost as a result of a viral outbreak following the sudden breakdown of the ozone purification system. In addition, the NCM suffered a devastating fire in the fall of 2007 that completely destroyed the hatchery and laboratory facilities although the BARD project samples were saved. Nevertheless, by studying alternate species a number of valuable findings and conclusions that can contribute to improved metamorphosis in commercially valuable marine species resulted from this collaborative effort. The Israeli group found that exposing white grouper larvae to external TH levels synchronized and increased the rate of metamorphosis. This suggested that sub-optimal synthesis of TH may be a major factor causing size heterogeneity in the larval population and high mortality through cannibalism by their larger more metamorphosed cohorts. Two protocols were developed to enrich the larvae with higher levels of the TH precursor, iodine; feeding iodine enriched Artemia or increasing the level of seawater iodine the larvae are exposed to. Results of accumulated iodine in gilthead seabream larvae indicated that the absorption of iodine from the water is markedly more efficient than feeding iodine enriched Artemia nauplii. Samples for TH, which will be analyzed shortly, will be able to determine if another dietary factor is lacking to effectively utilize surplus tissue iodine for TH synthesis. Moreover, these samples will also clarify which approach to enriching larvae with iodine, through the live food or exposure to iodine enriched seawater is the most efficient and cost effective. The American group found that moi larvae reared in ocean water, which possessed substantially higher iodine levels than those found in seawater well water, grew significantly larger, and showed increased survival compared with well water reared larvae. Larvae reared in ocean water also progressed more rapidly through developmental stages than those in low-iodine well seawater. In collaboration with Israeli counterparts, a highly specific and precise radioimmunoassay procedure for thyroid hormones and cortisol was developed. Taken altogether, the combined Hawaiian and Israeli collaborative research suggests that for teleost species of commercial value, adequate levels of environmental iodine are more determinate in metamorphosis than iodine levels in the live zooplankton food provided to the larvae. Insuring sufficiently high enough iodine in the ambient seawater offers a much more economical solution to improved metamorphosis than enriching the live food with costly liposomes incorporating iodine rich oils.
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Shpigel, Muki, Allen Place, William Koven, Oded (Odi) Zmora, Sheenan Harpaz, and Mordechai Harel. Development of Sodium Alginate Encapsulation of Diatom Concentrates as a Nutrient Delivery System to Enhance Growth and Survival of Post-Larvae Abalone. United States Department of Agriculture, September 2001. http://dx.doi.org/10.32747/2001.7586480.bard.
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The major bottlenecks in rearing the highly priced gastropod abalone (Haliotis spp.) are the slow growth rate and the high mortality during the first 8 to 12 weeks following metamorphosis and settling. The most likely reason flor these problems is related to nutritional deficiencies in the diatom diet on which the post larvae (PL) feed almost exclusively in captivity. Higher survival and improved growth rate will reduce the considerable expense of hatchery-nursery resisdence time and thereflore the production costs. BARD supported our research for one year only and the support was given to us in order to prove that "(1) Abalone PL feed on encapsulated diatoms, and (2) heterotrophic diatoms can be mass produced." In the course of this year we have developed a novel nutrient delivery system specifically designed to enhance growth and survival of post-larval abalone. This approach is based on the sodium-alginate encapsulation of heterotrophically grown diatoms or diatom extracts, including appetite-stimulating factors. Diatom species that attract the PL and promote the highest growth and survival have been identified. These were also tested by incorporating them (either intact cells or as cell extracts) into a sodium-alginate matrix while comparing the growth to that achieved when using diatoms (singel sp. or as a mixture). A number of potential chemoattractants to act as appetite-stimulating factors for abalone PL have been tested. Preliminary results show that the incorporation of the amino acid methionine at a level of 10-3M to the sodim alginate matrix leads to a marked enhancement of growth. The results ol these studies provided basic knowledge on the growth of abalone and showed that it is possible to obtain, on a regular basis, survival rates exceeding 10% for this stage. Prior to this study the survival rates ranged between 2-4%, less than half of the values achieved today. Several diatom species originated from the National Center for Mariculture (Nitzchia laevis, Navicula lenzi, Amphora T3, and Navicula tennerima) and Cylindrotheca fusiformis (2083, 2084, 2085, 2086 and 2087 UTEX strains, Austin TX) were tested for heterotrophic growth. Axenic colonies were initially obtained and following intensive selection cycles and mutagenesis treatments, Amphora T3, Navicula tennerima and Cylindrotheca fusiformis (2083 UTEX strain) were capable of growing under heterotrophic conditions and to sustain highly enriched mediums. A highly efficient selection procedure as well as cost effective matrix of media components were developed and optimized. Glucose was identified as the best carbon source for all diatom strains. Doubling times ranging from 20-40 h were observed, and stable heterotroph cultures at a densities range of 103-104 were achieved. Although current growth rates are not yet sufficient for full economical fermentation, we estimate that further selections and mutagenesis treatments cycles should result in much faster growing colonies suitable for a fermentor scale-up. As rightfully pointed out by one of the reviewers, "There would be no point in assessing the optimum levels of dietary inclusions into micro-capsules, if the post-larvae cannot be induced to consume those capsules in the first place." We believe that the results of the first year of research provide a foundationfor the continuation of this research following the objectives put forth in the original proposal. Future work should concentrate on the optimization of incorporation of intact cells and cell extracts of the developed heterotrophic strains in the alginate matrix, as well as improving this delivery system by including liposomes and chemoattractants to ensure food consumption and enhanced growth.