The importance of parental nutritional status on planktotrophic larvae was investigated in both laboratory-conditioned and field (populations) parents of two New Zealand echinoderms: the sea urchin Pseudechinus huttoni and the starfish Sclerasterias mollis. Three questions were addressed: (i) Does parental nutritional status affect the reproductive features (gonad index, gametogenesis, fecundity and biochemical composition) both in the laboratory and under natural conditions? (ii) Does parental nutritional status affect egg characteristics (diameter, number, dry weight, fertilization rate and biochemical composition)? (iii) Are the characteristics of larvae (growth, development, morphology, mortality rate and body composition) influenced by parental or larval nutrition (or both)? To answer the first question, adult P. huttoni and S. mollis were maintained in the laboratory with a low or high diet (in terms of quantity and quality for P. huttoni, and in terms of quantity for S. mollis) for one year. The effect of low and high diets on reproductive features was studied and the same parameters were studied in two parental populations with dissimilar food availability (for P. huttoni: Otago Shelf and Doubtful Sound populations; for S. mollis: Otago inshore and offshore populations). To address the second question, egg characteristics of the laboratory-held and field parents were measured. The third question was answered by rearing larvae of the laboratory and field parents with both low and high concentration planktonic diets. P. huttoni reared in the laboratory with a higher food ration had greater gonad indices and lipid concentration and larger oocyte area. Sea urchins from the Doubtful Sound population had higher food availability, greater gonad lipid concentration and larger oocytes. Parental nutrition had some effect on the characteristics of the egg in P. huttoni. The laboratory-held urchins fed a high diet produced larger eggs: P. huttoni from Doubtful Sound produced larger eggs with a greater carbohydrate concentration. P. huttoni larvae from low-fed laboratory and Otago Shelf parents had faster development The effect of larval nutrition was more important than parental food availability on larval growth and development. Feeding parents in the laboratory had no effect on larval morphology but larvae from Doubtful Sound, which had better food availability, had longer arms relative to body width. A higher cell concentration in the planktonic diet led to shorter larval arm relative to body width. In S. mollis reared in the laboratory, a higher food ration led to larger gonad and pyloric caeca indices. The starfish from an Otago inshore population mainly had a higher gonad index than those from an Otago offshore population. In the laboratory-held parents S. mollis, nutrition had no effect on the egg characteristics. In the field, starfish with higher food availability produced smaller eggs with lower carbohydrate concentration. There was no significant difference between development rates of S. mollis larvae from low and high fed laboratory parents. However, those from the Otago inshore parents, with better food availability, had faster development than the larvae from Otago offshore parents. In S. mollis larvae, the origin of the parents (either from the laboratory or the field) had no effect on larval shape. A higher concentration planktonic diet led to longer larvae relative to body width in larvae from high-fed laboratory parents. In both P. huttoni and S. mollis, parental and larval diet had no effect on rate of instantaneous larval mortality. In both P. huttoni and S. mollis larvae, biochemical composition of the larvae and the egg were different to each other. Egg reserves appear not to be a factor which affects larval characteristics in these species.

<p>Diversity in coloration is a common phenomenon in marine invertebrates, although the ecological significance of the diversity is often unknown. Patterns of geographic variability, particularly with respect to color phenotypes, are evident in many organisms and may provide visual evidence of natural selection. </p><p>This dissertation examined the geographic and genetic variability of color patterns and morphology of the sea urchin <italic>Lytechinus variegatus </italic>. This study had 3 objectives: 1) to describe and quantify phenotypic diversity--color and morphology--throughout the geographic range; 2) to determine the heritability of color in genetic crosses between individuals with similar and differing phenotype; 3) to assess the degree of genetic divergence between and within the regions and congruence between the phylogenetic mitochondrial COI data and color phenotypes seen in the field.</p><p>The distribution of color phenotypes in the field is highly variable across the geographic range which stretches from Beaufort NC to southern Brazil and throughout the Gulf of Mexico and Caribbean. Urchins in each of the 5 regions sampled (Beaufort, Gulf, Keys, Panama and Brazil) have a distinct phenotypic composition despite the presence of similar color morphs. The two regions at the extremes--Beaufort and Brazil--demonstrate the most homogeneous phenotypes, each with a single dominant color morph. The Keys has the most heterogeneous composition with all 14 color morphs present. Morphological diversity mirrors color diversity in being highly variable across the range. Urchins in Beaufort are significantly different morphologically from urchins in the central portion of the range, with thicker, flatter tests and longer more robust spines.</p><p>The heritability of color phenotypes and morphology suggests that genes rather than environment have a major role in color phenotype and patterning as well as morphology in test, spines and lanterns. F₁ and F₂ offspring of Beaufort and Tavernier Key crosses resemble the parental phenotypes in both morphology and color phenotype. Hybrids from crosses between regions have a mixed color palette and intermediate morphological characteristics. The crosses establish that in <italic>L. variegatus </italic>the white phenotype is a dominant autosomal trait and green and purple are recessive and co-expressed. Patterning of the test and spines is dominant to non-patterning. </p><p>Analysis of the mitochondrial COI gene in urchins from Beaufort, Gulf and Keys regions revealed two clades. Clade 1 composed exclusively of Keys urchins differed significantly (F_ST = 0.89, <italic>P</italic> < 0.001) from Clade 2 composed of urchins from Beaufort, Gulf and Keys. Genetic differentiation within Clade 2 was zero, indicating that urchins in these regions are genetically identical. The genetic split between phenotypically indistinguishable Keys urchins suggests cryptic species. Genetic differentiation does not concord with phenotypic and morphological differentiation. No structure was detected with regards to color phenotype in either clade or region of origin in Clade 2.</p> / Dissertation

Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Su Ürünleri Temel Bilimleri Anabilim Dalı, 2008. / Kaynakça var.

Research and development in aquaculture has supported the knowledge-based development of the sector over the last decades. In particular, species diversification is playing an important role to ensure sustainability of the industry and helping to reduce pressure on wild stocks of those aquatic species for which farming technology is still at the early stages. Due to the increasing pressures on more traditional carnivorous marine finfish species (aquafeed reliance on fishmeal and fish oil, environmental impact, market price) low trophic organisms are receiving more attention to provide sustainable alternatives and integrate production activities with the aim of reducing environmental impacts and to provide secondary high value crops. Integrated Multi-Trophic Aquaculture (IMTA) systems are therefore at the forefront of innovation in the industry. Several invertebrate species have been investigated and tested as integral part of IMTA (mussels, oysters, abalone and macroalgae) and echinoderms have also been considered as good candidates for the future development of this technology. In order to allow for a more widespread uptake of integrated aquaculture, several technical and biological challenges need to be overcome, including a reliable supply of juveniles. In recent years, this has prompted investigation on Echiniculture as a whole and on hatchery technologies in particular. This PhD investigated key constraints in edible sea urchin (Paracentrotus lividus) juvenile production with the aim to improve commercial sea urchin hatchery outputs. The research firstly focused on larval nutrition (Chapter 3 and 4) and specifically tested the hypothesis that larvae required higher dietary inputs of long chain fatty acids than those provided by Dunaliella tertiolecta, a microalgae species widely used in echinoderm larval rearing. Fatty acid composition of P. lividus eggs, investigated in Chapter 3, supported this hypothesis, which was further confirmed by the results obtained in Chapter 4 where microalgae (Cricosphaera elongata, Pleurochrisis carterae and Tetraselmis suecica) with a more balanced fatty acid profile, in particular richer in long chain fatty acids, were employed. This resulted in a significantly improved larval development and survival. Results also indicated that these alternative microalgae species could be successfully grown without modification of the microalgae production protocols in the hatchery where the experimentation had taken place. The third experimental chapter compared static and flow through systems which provides more stable water quality through constant water exchange and reduces larval handling and associated stress. Results indicated that larval survival was significantly improved by the flow-through system and the need for tank cleaning was reduced (three versus seven times per larval cycle when using flow-through and static rearing systems respectively). However, water quality, based on the parameters assessed (NH4, PO4-3, NO2 and NO3), did not show any significant differences between systems. Reduced handling could have therefore played the most important role in promoting larval survival. Both these trials resulted in a significant 5 to 20 % increased survival. A follow-up study, combining flow-through with more suitable microalgae, should be carried out and could result in even further enhanced survival. Then, chapters 6 and 7 focused on broodstock nutrition and subsequent improvement of gamete quantity and quality. These two trials aimed to explore and describe the biological effects that some important nutrients, such as proteins, lipids, fatty acids and carotenoids, have on urchins’ somatic and gonadal growth, gonad biochemical composition during gametogenesis, fecundity and maternal provisioning to developing embryos. Results from the experiment described in Chapter 6 indicated that higher protein content can improve somatic growth in P. lividus adults and that more expensive, protein-, lipid- and energy-rich diets do not significantly enhance fecundity or offspring performance. Results, moreover, highlighted the need for a specifically formulated broodstock diet and gave some insights into what its composition should be, especially in relation to carotenoids. In Chapter 7, fatty acid profiles of P. lividus gonads throughout gametogenesis were studied for the first time. It was observed that, among Long Chain Polyunsaturated Fatty Acids (LC-PUFAs), Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) are primarily accumulated during gametogenesis, whilst Arachidonic acid (ARA) appears to be independent of dietary input. In addition, it was clearly shown that ARA is the only LC-PUFA accumulated in the eggs along with Non Methylene Interrupted Fatty Acids (NMI FAs). As well as looking at the biological effects of different diets on fatty acid profiles of gonadal and larval tissues, the work also expanded on a more fundamental level to explore the metabolic pathway through which precursors could be used by sea urchins for the endogenous production of long chain fatty acids (Chapter 8). Three Expressed Sequence Tags (ESTs) for putative fatty acyl desaturases, one of which was closely related to Octopus vulgaris ∆5-like fatty acyl desaturase, were identified. The newly cloned putative desaturase of P. lividus possessed all typical features of other fatty acyl desaturases. However, because of time constraints, functional characterisation, originally planned, of the new protein could not be performed and further research effort is needed to investigate this important aspect of sea urchin physiology. Overall, the aim of this research project has been achieved as it provided a set of exploitable results and protocols to improve hatchery practices for the production of P. lividus juvenile. However, more research is required to investigate some of the underlying mechanisms behind the observed biological effects such as delay in larval development when T. suecica was used as larval feed, increased broodstock fecundity, improved larval survival in the flow-through system and higher gonadal concentration of some fatty acids (mainly DHA) than provided in the feed.

No description available.

Ten species of shallow water echinoid are found on the subtropical east coast of South Africa. Although their distributions are patchy, the most common species, Echinometra mathaei, stomopneustes variolaris and Diadema savignyi, are nontheless conspicuous components of intertidal communities on this coast. As little was known about these three species, the overall intention of this study was to provide some fundemental information on their biology and ecology. For the purposes of achieving this aim a life history approach was adopted, where the relative investments by each species in growth, maintenance and reproduction were investigated and compared. These patterns of investment were then related to the habitat occupied by each species, in an attempt to identify the selective forces which may have been implicated in shaping their life histories. It was apparent from the results of investigations conducted between January 1991 and June 1993 that there were distinct differences in the patterns of investment in growth, maintenance and reproduction between the three species. The life history of S. variolaris, which occupied exposed habitats in the lower intertidal, was characterised by a large investment in maintenance, lower reproductive output, slower growth and a longer lifespan, relative to the other two species. In contrast, Q. savignyi, which inhabited less exposed mid-shore pools, had a relatively higher reproductive output, more rapid growth, a smaller investment in maintenance and a shorter lifespan. While selection ln S. variolaris and Q. savignyi appears to favour survival and reproduction respectively, the life history of E. mathaei, a species which also occupies mid-shore pools, was balanced between these two extremes, allocating sufficient resources to maintenance to permit tolerance of harsh physical conditions while still making a moderate investment in reproduction over a lifespan of intermediate duration. The predictions generated by the r-K selection and "bet hedging" theories of life history evolution, were applied in the process of speculating on the selective forces which may have shaped these life histories. However, it was found that neither set of predictions and associated selective forces could adequately explain the observed life histories. Rather, it seemed that the life histories of the three species represented evolved responses to the direct and indirect effects of exposure to wave action and sand movements which dominate the intertidal environment on the South African east coast. In the exposed lower intertidal, unpredictable recruitment, drag and impact forces associated with wave action, which impose limits to body size and necessitate a large investment in maintenance to ensure survival, select for slow growth, low reproductive output and high longevity. In contrast reproduction and growth of species occupying the more sheltered mid-shore pool habitats would be less effected by the demands of maintenance investment or limits to body size. In addition predictable recruitment in the mid-shore, would obviate the need for long life in order to ensure a contribution to future generations. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1993.

Although rather inconspicuous on healthy coral reefs, macroalgae form the basis of coral food webs. Today, macroalgae are generally increasing and many reefs undergo transitions from coral to macroalgal dominance resulting from e.g. enhanced nutrient loading or increased fishing. This thesis aims to investigate the relative importance of top-down and bottom-up regulation, and different herbivore types, on macroalgal distribution, fecundity and community composition on coral reefs. Papers I and II indicate that macroalgal abundance in a coral reef system is largely governed by top-down regulation through grazing by herbivores, while bottom-up regulation through enhanced nutrient availability rather influence algal species composition. Paper II also shows that these regulating effects are not as evident in an area with relatively strong water motion, suggesting that impacts of anthropogenic disturbance may be site-specific. Paper III shows that herbivory is an important factor influencing macroalgal growth and subsequent reproduction. Furthermore, Paper IV and V conclude that efficiency in removing macroalgal biomass is dependent on the type of dominant herbivore, where sea urchins seem to be more effective than fish. Paper IV indicates a seasonal variation in macroalgal biomass and distribution in a small geographic scale but with relatively high temporal resolution. Paper V on the other hand shows these same effects, but with a focus on geographic variation, including a large part of the East African region, as well as between year temporal variations in Kenya. Together, results from the two latter studies indicate that herbivory by fish may not be able to prevent a macroalgal bloom in a degraded system where substrate availability for algal colonization is high, but that it may still facilitate coral recovery over time. Thus, a large algal biomass may not necessarily indicate a reef beyond the possibility of recovery. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Accepted. Paper 4: Manuscript. Paper 5: Manuscript.</p>

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 28-33). / 50 leaves, bound ill. 29 cm

Thesis (doctoral)--University of Stockholm, 1983. / Includes bibliographical references (p. 39-44 (first group)).

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 102-110). Description: xiii, 110 leaves : ill. ; 29 cm.