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Hybridization among abalone species has been suggested as a possible means to increase their growth rates for aquaculture. As a first step to test the usefulness of the hybrids of Japanese abalone species ( Haliotis discus discus, Haliotis gigantea and Haliotis madaka) for aquaculture, we characterized the genetic background and gonad development of hybrids that were produced by artificial insemination. The hybrid status of the resulting offspring was confirmed by assaying 14 allozymes and by RFLP analysis of the 16s rRNA and cytochrome oxidase I (COI) regions of mtDNA using 13 restriction enzymes. Histological examination of the gonads of the hybrids was conducted in comparison with those of the parental species. Cross-breeding among the three species was conducted successfully in all combinations although with lower fertilization rates (means of 1.3–60.8%) than the parental species (34.3–90%). Crosses between H. discus discus and H. madaka had higher fertilization rates (22.4–60.8%) than those involving H. gigantea (1.3–19.9%). The hybrids were ascertained by the presence of both parental genotypes at the LDH-A, ME-A, MDH-A and GPI loci. The maternal origin of the hybrid mtDNA was confirmed by digestion with DdeI, TaqI, HpaII of the COI region. No polymorphism was observed in the 16S rRNA region. The hybrids had gonadal development and maturity stages similar to the parental species up to fully mature oocytes and sperm. They spawned upon stimulation and produced viable offspring with high fertilization rates and successful development to the juvenile stage in back- and homologous hybrid crosses. [ABSTRACT FROM AUTHOR]

Abalone are common herbivores throughout temperate and tropical waters, and yet the contribution of red and brown macroalgae to the diet of wild abalone remains unclear. In the northern hemisphere, adult abalone are considered to consume predominantly brown algae, but in the southern hemisphere abalone are thought to prefer red algae. Conventional methods such as gut content analysis and feeding trials provide some insight into diet choice, but the associated biases of these techniques create uncertainty surrounding the aforementioned variability in abalone diet. We use combined stable isotope and fatty acid analysis to determine the relative contribution of red algae, brown algae and detritus/microalgae to the diet of wild abalone in Tasmanian waters. Stable isotopes of carbon suggest that brown algae and/detritus are a more important source of carbon than red algae. Fatty acid analysis confirmed the larger contribution of brown algae to the diet of abalone, and also identified the bacterial and diatom component of detritus to be an important contributor to abalone diet. These results show combined use of chemical tracers to be a promising technique for resolving abalone diet, and challenge current perceptions regarding spatial variability in abalone diet choice. [ABSTRACT FROM AUTHOR]

The article examines climate change contributing to range reductions and localized extinctions in northern and flat abalones. The section analyzes northern and flat abalone along the Pacific coast of the United States, comparing data with historic records from 30 years ago to test whether there has been a shift in the southern range as would be predicted with ocean warming. It focuses on northern abalone which is a species of concern, has a broad geographic distribution, and was once the basis of important commercial and recreational fisheries.

In order to develop a highly efficient method for mass production of triploid Pacific abalone Haliotis discus hannai, caffeine treatment that is safe and inexpensive was optimized. To suppress the first meiotic division, fertilized eggs were exposed to either a 10- or 15-mM caffeine solution for 24 min beginning at 12 min after fertilization. In most treated batches, the rates of cleaved eggs showed no significant difference from the control batches. However, in most treated batches, the rates of occurrence of normal larvae and the survival rates of the early juveniles were significantly lower than those of the controls. The triploid rates at 6 days to 11 months after settlement in all the treated batches were extremely high (91–100%). There was no significant difference in the mean triploid rates between 10- and 15-mM caffeine treatments. These results suggest that both treatment conditions were conducive to triploid abalone production. One live 2n/3n mosaic specimen was found in the treated batches. However, since the frequency of mosaic was extremely low, the mosaicism would probably not have an adverse effect on the stable production of triploid abalones. [ABSTRACT FROM AUTHOR]

Triploid induction in Australian greenlip abalone, Haliotis laevigata (Donovan), was conducted by blocking the formation of the second polar body using cytochalasin B (CB). Twenty minutes after fertilization, the zygotes of greenlip abalone were treated with four CB concentrations (0, 0.25, 0.5 and 0.75 mg L−1) for 10, 15 and 20 min. The ploidy of resultant larvae was determined using flow cytometry at 72-h post fertilization. Our study showed that fertilization, hatching, survival and induced triploidy of abalone larvae were significantly affected by the CB concentration and treatment duration. The effective range of CB concentration for triploid induction on greenlip abalone was 0.5–0.75 mg L−1 with an induction duration of 10–15 min. The results indicate that the most effective treatment combination for triploid induction in greenlip abalone is 0.5 mg CB L−1 for 15 min starting at 20-min post fertilization. [ABSTRACT FROM AUTHOR]

The article presents a study regarding application of various DNA extraction methodologies on abalone, haliotis midae, larvae and juveniles for fluorescent amplified fragment length polymorphism (AFLP) analysis. DNA suitable for molecular studies pertaining to abalone is commonly obtained from the epipodia using non-destructive sampling techniques. DNA obtained from the extraction protocols was used for fluorescent ALP analysis. AFLP amplifications were conducted with the AFLP Plant Mapping Kit.

The neutral red retention (NRR) assay was used to evaluate the effects of air exposure on lysosomal membrane integrity in the haemolymph of blacklip abalone, Haliotis rubra, and its subsequent recovery in water. After acclimation in 16°C water for 7 days, abalone were exposed to an air temperature of 7, 16 or 23°C for 12 h in the air exposure experiment or to these three air temperatures, e.g., for 12, 24 or 36 h, followed by re-immersion in 16°C water in the lysosomal membrane stability recovery experiment. Statistical analyses of the air exposure experiment showed that when abalone were exposed to different air temperatures (7, 16 or 23°C), the lysosomal membrane stability was significantly affected by the air temperature, the exposure duration and their interaction. Air temperature similar to the acclimation temperature had a significantly lower impact on the lysosomal membrane stability within the initial 4.5 h in comparison with the other two temperatures in the same period. The lysosomal membrane stability recovery experiment showed that after air exposure durations of 12, 24 or 36 h, the re-stabilization of the lysosomal membrane was faster in the animals exposed to lower temperatures than those exposed to higher temperatures. The recovery of the lysosomal membrane stability in abalone exposed to lower 7°C air temperature was not significantly affected ( F2, 66=0.251, P=0.779) by the exposure durations (12, 24 and 36 h) used in this study. Alternatively, the lysosomal membrane stability in abalone exposed to higher air temperatures of 16 or 23°C recovered at a faster rate when subjected to shorter durations of air exposure ( F2, 66=3.663, P=0.031 and F1, 44=17.057, P<0.001 for 16 and 23°C respectively). [ABSTRACT FROM AUTHOR]

The specimens of Patella intermedia, Patella rustica, Patella ulyssiponensis and Patella vulgata were analysed for morphological and morphometric characters, and for the resistance to compression and crushing to a force applied at the apex. Shell shape in these species ranged from the high symmetrical cone, with a rounded base of P. rustica, to the flat, asymmetrical, narrow-pear-shaped base of P. ulyssiponensis. P. intermedia and P. vulgata showed intermediate morphologies. Shell thickness increased linearly with age, but differed in the four limpets. P. rustica had the thickest shells, and P. ulyssiponensis and P. vulgata had the thinnest shells. P. intermedia displayed intermediate shell thickness. Considering deformability and toughness, P. intermedia shells usually needed the highest force to compress in height, the highest pressure to collapse, and were appreciably deformed at collapse. On the opposite side, P. ulyssiponensis shells usually needed the lowest force to compress in height, the lowest pressure to collapse, and were much less deformed at collapse. P. intermedia shells were therefore the most deformable and tough, and P. ulyssiponensis, the most stiff and fragile. P. rustica and P. vulgata shells displayed intermediate behaviour. However, numerical simulations based on the finite element method using the experimentally determined shells’ geometry and thickness, but considering similar shells’ material and structure in the four species, predicted that shell toughness should be decreased in the order P. rustica >> P. intermedia > P. vulgata >> P. ulyssiponensis. P. rustica shells’ geometry (a high and centred cone) and thickness (very thick) were therefore, theoretically, the most fitted for shells to resist crushing by compression. Yet, in the experimental tests, they were not the most resistant shells. It was concluded that resistance to crushing was not a direct function of shell morphology and morphometry, but appeared to be mainly determined by shell deformability. This is most probably related to differences in the internal composition and architecture of the shell in the four species. By comparison with data reported in the literature on the pressures normally exerted by ocean waves, it was concluded that these limpets have resistances to crushing in far excess to pressures normally endured in nature, being therefore unlikely that these species are crushed by the action of even very strong waves on shores. Hard objects, like logs and boulders, can be hurled onto the shore by waves, and constitute a much greater threat to limpets than the waves themselves. The high toughness of the limpet shell can be related to resistance to the impact of incidental hard objects. There was no direct relationship between the habit preferences of these limpets and the resistance to crushing. Other factors are involved in the distribution of these species in the shores. [ABSTRACT FROM AUTHOR]

This study presents linkage maps for the Pacific abalone (Haliotis discus hannai) based on 180 microsatellite DNA markers. Linkage mapping was performed using three F1 outbred families, and a composite linkage map for each sex was generated by incorporating map information from the multiple families. A total of 160 markers are placed on the consolidated female map and 167 markers on the male map. The numbers of linkage groups in the composite female and male maps are 19 and 18, respectively; however, by aligning the two maps, 18 linkage groups are formed, which are consistent with the haploid chromosome number of H. discus hannai. The female map spans 888.1 cM (Kosambi) with an average spacing of 6.3 cM; the male map spans 702.4 cM with an average spacing of 4.7 cM. However, we encountered several linkage groups that show a high level of heterogeneity in recombination rate between families even within the same sex, which reduces the precision of the consolidated maps. Nevertheless, we suggest that the composite maps are of significant potential use as a scaffold to further extend the coverage of the H. discus hannai genome with additional markers. [ABSTRACT FROM AUTHOR]

Haliotis asinina is a broadcast-spawning mollusc that inhabits Indo-Pacific coral reefs. This tropical abalone develops through a nonfeeding larval stage that is competent to settle on specific species of coralline algae after 3–4 days in the plankton. Failure to contact an inductive algae within 10 days of hatching usually results in death. These life cycle characteristics suggest a limited capacity for dispersal and thus gene flow. This makes H. asinina particularly suitable for elucidating phylogeographical structure throughout the Indo-Malay Archipelagoes, and eastern Indian and western Pacific Oceans, all regions of biogeographical complexity and high conservation value. We assayed 482 bp of the mitochondrial cytochrome oxidase II gene in 206 abalone collected from 16 geographically discrete sites across the Indian and Pacific Oceans and Indo-Malay Archipelagoes. DNA sequence variation was analysed via population genetics and phylogenetics, and by nested clade analyses (NCA). Our data resolved clear phylogeographical breaks among major biogeographical regions, with sequence divergences ranging from a high of 3.7% and 3.0% between Indian and Pacific sites and Pacific and Indo-Malay sites, respectively, to a low of 1.1% between Indian and Indo-Malay sites. Despite the apparent limited dispersal capacity of H. asinina, no finer scale phylogeographical structure was resolved within the respective biogeographical regions. However,amova and NCA identified several significant associations between haplotypes and geographical distribution, most notably higher gene flow among geographical populations associated with major ocean currents. Our study provides further evidence that larval dispersal capacity alone is not a good predictor of population genetic structure in marine invertebrates. We infer instead that a combination of historical events (long–term barriers followed by range expansion associated with Pleistocene sea level changes) and contemporary processes (gene flow restricted by life history and oceanography) have shaped observed patterns of H. asinina phylogeography. [ABSTRACT FROM AUTHOR]

1. Loop models of ecological and socio-economic systems were developed to analyse and predict the impact of a possible accidental introduction (escapes) of the abalone Haliotis discus hannai into a benthic community of north-central Chile. 2. Although the 'new' ecological system resulting from a successful invasion of abalone would be locally stable, the establishment of a self-enhanced dynamic of recruits would transform this into an unstable system. 3. The harvest of the kelp, Lessonia trabeculata and other macroalgae is not recommended because this destabilizes the system. The harvest of abalone adults is only sustainable if they do not exert a negative effect upon other native invertebrates. 4. The eco-social model showed three important results: (I) if the variables 'Price' and 'Farming' are in expansion and stationary dynamics, then the models were found unstable; (2) a self-enhanced dynamic of abalone recruits tends toward instability; and (3) the harvest of the kelp L. trabeculata and other macroalgae would be non-sustainable. 5. Based on our results, the sustainable development of extensive farming of H. discus hannai in the sea would be not reached. If it is done, an intensive monitoring of the community after introduction into the system is strongly recommended. Likewise, the farming of macroalgal species (source of food for abalone) should be promoted in order to avoid harvesting of macroalgae from natural systems. [ABSTRACT FROM AUTHOR]

The thermoregulatory behaviour of green abalone Haliotis fulgens and pink abalone H. corrugata was investigated. Haliotis fulgens juveniles ranging in wet weight from 3.0 to 3.3 g and from 28.7 to 30.5 mm shell length and of H. corrugata 2.0 g and 25.7 mm in shell length were exposed to 19°C for 30 days in a flow-through water system. Temperature preference was determined in a horizontal thermal gradient and was found to be 25.4°C for green abalone and 25.0°C for pink abalone. Displacement velocity was 4.3 cm h−1 for H. fulgens and 12.8 cm h−1 for H. corrugata. The optimum temperature for growth calculated for both abalone species was 24.6 and 24.5°C respectively. The critical thermal maxima (CTMax) of H. fulgens and H. corrugata were determined as a measure of thermal tolerance. Abalones were subjected to increasing water temperatures at a rate of 1°C on 30 min until they detached from the substrate. The CTMax at 50% were 33.6 and 32.0°C for green and pink abalone respectively. The results are discussed in relation to site selection and commercial rearing. [ABSTRACT FROM AUTHOR]

In the intertidal limpet Patelloida pygmaea, two distinctive morphs, the forms pygmaea and conulus, have been recorded. The former possesses a flat elongated shell, and the latter has an extremely high round shell. It has been observed in the field that pygmaea is found on oyster shells Crassostrea gigas. The form conulus uses an unusual substrate for attachment. It is found on the living shells of the intertidal gastropod Batillaria cumingi. Although conulus is normally found only on shells of Batillaria, it can also be found on oyster shells when pygmaea and Batillaria shells are not present in nature. An electrophoretic analysis of allozymes showed that these two forms are reproductively isolated from each other and coexist without gene exchange on the same mudflat. Laboratory experiments showed that pygmaea prefers oyster shells and conulus prefers Batillaria shells as substrates for attachment when both oyster and Batillaria shells are present. The form pygmaea did not attach to Batillaria shells, even when only Batillaria shells were available. However, conulus also attached to oyster shells when Batillaria shells were not available. The proportion of individuals of conulus that attached to oyster shells decreased significantly when pygmaea was attaching to the oyster shells. These results suggest that pygmaea is ecologically more specialized to living on oyster shells than conulus. [ABSTRACT FROM AUTHOR]

Patella vulgata is a boreal cold temperate species and is the dominant limpet in northern Europe. Few works have focussed on the population genetics of this species. Therefore, the aim of this work was to assess the degree of genetic and morphological differentiation of P. vulgata on a macroscale by using 20 allozyme loci and 6 morphological variables. Samples were taken from the following locations: Dingle Peninsula (Southwest Ireland), Port Erin (Southwest Isle of Man), St. Bees Head (north Cumbria, England), St. Agnes Head (north Cornwall, England), Cellar Beach (south Devon, England), Whitley Bay (north Newcastle-Upon-Tyne, England), Sines (Portugal), and Pointe de Chanchardon, La Rochelle (Bay of Biscay, France). Morphological variables were analysed by the multivariate Canonical discriminant analysis. Genetic variation was assessed by diversity measures such as polymorphism and heterozygosity; genetic subdivision of P. vulgata population was determined by the estimator θ of F ST, and the genetic similarity between populations was measured by Nei’s genetic identity. No significant morphological differentiation was observed among samples. Moderate genetic population subdivision was observed (θ = 0.137±0.074) despite great geographic distances. The minimum genetic identity observed was between Ireland and France ( I = 0.942) and maximum was observed between Portugal and north-east England ( I=0.998). Two main groups were shown by UPGMA cluster analysis ( I = 0.965). One formed by Irish, Manx, north Cumbria, and curiously, south Devon samples, while the second includes Portuguese, French, north-Newcastle-upon-thyne, and north Cornwall samples. No association ( g = 0.956; p>0.050) was found between pair-wise genetic divergence and geographic distance separating subpopulations, mainly due to an unexpected pattern of genetic heterogeneity found in Southwest England. [ABSTRACT FROM AUTHOR]

Presumed hybrids between Haliotis rufescens and H. fulgens abalones, produced in a commercial abalone laboratory, were evaluated for progeny viability, gonad characteristics and for their ‘true’ status as hybrids by means of allozyme and microsatellite analyses. Four out of 10 evaluated allozyme loci proved to be useful for the genetic certification of hybrids, Gpi, Mdh-1, Mdh-2 and Sod, as they had exclusive alleles for each of the abalone reference species from which the presumed hybrids were produced. Three microsatellite loci were also evaluated for their usefulness in abalone hybrid certification. Two were not useful for hybrid certification as the reference abalone species shared some of the same alleles. The third loci ( Hka 56) also had shared alleles between the two species, but at very different frequencies. Therefore, this permitted a presumptive certification of hybrids, which, however, was not error-proof as two allozyme certified hybrids were wrongly classified as H. rufescens rather than as hybrids. Progeny viability of the only female certified to be a hybrid was significantly lower compared with one viability of the other females spawned, which were certified as H. rufescens. However, the number of eggs spawned by the only certified hybrid female was as large as those spawned by females certified as H. rufescens. Gonads of abalones sampled for the macroscopic appearance of sterility indicated that in the absence of any gonad development, no distinctive difference allows for hybrid identification, as there were undifferentiated individuals that were both hybrid and non-hybrid. On the other hand, two certified hybrid males were characterized by spermatocytes being the most abundant gamete type, although one had some spermatozoa present, indicating only partial sterility. Among the two female hybrids found, vitellogenesis was observed to proceed up to vitellogenic oocytes. [ABSTRACT FROM AUTHOR]

Surfaces from the habitat of adult Haliotis rubra were tested as inducers of larval settlement to determine the cues that larvae may respond to in the field. Settlement was high on the green algal species Ulva australis and Ulva compressa (Chlorophyta), the articulated coralline algae Amphiroa anceps and Corallina officinalis, and encrusting coralline algae (Rhodophyta). Biofilmed abiotic surfaces such as rocks, sand and shells did not induce settlement. Ulvella lens was also included as a control. Treatment of U. australis, A. anceps and C. officinalis with antibiotics to reduce bacterial films on the surface did not reduce the settlement response of H. rubra larvae. Similarly, treatment of these species and encrusting coralline algae with germanium dioxide to reduce diatom growth did not significantly reduce larval settlement. These results suggest that macroalgae, particularly green algal species, may play an important role in the recruitment of H. rubra larvae in the field and can be used to induce larval settlement in hatchery culture. [ABSTRACT FROM AUTHOR]

Hemocyanins are large copper-containing respiratory proteins that play a role in oxygen transport in many molluscs. In some species only one hemocyanin isoform is present while in others two are expressed. The physiological relevance of these isoforms is unclear and the developmental and tissue-specific expression of hemocyanin genes is largely unknown. Here we show that two hemocyanin genes in the gastropod Haliotis asinina, which encode H. asinina hemocyanin (HaH1) and HaH2 isoforms, are developmentally expressed. These genes initially are expressed in a small number of mesenchyme cells at trochophore and pre-torsional veliger stages, with HaH1 expression slightly preceding HaH2. These cells largely are localized to the visceral mass, although a small number of cells are present in head and foot regions. Following metamorphosis the isoforms show overlapping as well as isoform-specific expression profiles, suggesting some degree of isoform-specific function. [ABSTRACT FROM AUTHOR]

Six species of abalones (Haliotidae) are found on the Korean coasts. Identification and characterization of these abalones are usually based on morphologic characters. In this research we compared the partial sequences of the mitochondrial 16S ribosomal RNA and cytochrome c oxidase subunit I genes to identify species using molecular data and to determine their phylogenetic relationships. Sequence alignments and phylogenetic analysis revealed that the 6 species fell into 2 distinct groups which were genetically distant from each other and exhibited little internal phylogenetic resolution. One group included Haliotis discus hannai, H. discus discus, H. madaka, and H. gigantea, while the other group contained H. diversicolor supertexta and H. diversicolor diversicolor. The 16S rRNA sequences were relatively more conserved than to the COI sequences, but both gene sequences provided sufficient phylogenetic information to distinguish among the 6 species of Pacific abalone, and thus could be valuable molecular characters for species identification. [ABSTRACT FROM AUTHOR]

We studied the distribution, abundance and size structure of three limpet species (Patella rustica, Patella candei crenata and Patella aspera) throughout the rocky intertidal zone of the Canary Archipelago. We used a stratified and hierarchical sampling strategy that involved the study of three intertidal zones (high, intermediate and low intertidal) across eight islands with three random locations per island and three randomly selected sites within locations. We did not observe any specimens of P. candei candei. For the entire archipelago, the least abundant species was P. candei crenata (0.02±0.05 individuals/0.25 m2, average ± SD), the species with significantly greatest sizes (26.8±11.08 mm, average ± SD) and of highest commercial interest. Patellaaspera (0.08±0.37 individuals/0.25 m2) and P. rustica (0.069±0.16 individuals/0.25 m2) showed higher abundance, but smaller sizes (21.0±9.21 and 18.1±7.94 mm, respectively). The three zones influence how these species are distributed and these distribution patterns are homogenous among islands. Patella rustica was observed to be more abundant in the intermediate zone and P. aspera in the lower zone, while P. candei crenata showed similar abundance in the low and intermediate zones. This vertical variability is masked by a horizontal variability on small and intermediate scales (10 s to 1000 s of meters), but not among islands (10 s to 100 s of km). This fact can be attributed to the low abundance of the limpet species in the locations studied, as a result of overexploitation of this resource in the Canary Islands. Consequently, there is a need for management and control measures. [ABSTRACT FROM AUTHOR]

Abstract: The growth and self-assembly of aragonitic calcium carbonate found in the shell of abalone (Haliotis) is described. This was accomplished through the close examination of laboratory-grown flat pearl samples and cross-sectional slices of the nacreous shell. Further understanding of the sequenced assembly has been obtained. It has been confirmed that the growth of the aragonite component of the composite occurs by the successive nucleation of aragonite crystals and their arrest by means of a protein-mediated mechanism; it takes place in the “Christmas-tree pattern” [Nature 49 (1994) 371]. It is shown that the protein layer is virtually absent where plates on a same plane abut (along lateral surfaces of tiles). This suggests a mechanism of c-axis aragonite growth arrest by the deposition of a protein layer of approximately 20–30nm that is periodically activated and determines the thickness of the aragonite platelets, which are remarkably constant (0.5μm). This platelet size was measured for animals with shell diameters of 10, 50, and 200mm and was found to be constant. The overall growth process is expressed in terms of parameters incorporating the anisotropy of growth velocity in aragonite (Vc, the velocity along c axis, and Vab, the velocity in basal plane). Comparison of laboratory-raised and naturally-grown abalone indicates growth regulated by the level of proteinaceous saturation. Naturally-grown abalone exhibits mesolayers (growth bands) ∼0.3mm apart; it is proposed that they result from seasonal interruptions in feeding patterns, creating thicker (∼10–20μm) layers of protein. These mesolayers play a critical role in the mechanical properties, and are powerful crack deflectors. The viscoplastic deformation of the organic inter-tile layers is responsible for the significant improvement of tensile strength over the tensile strength of monolithic aragonite. [Copyright &y& Elsevier]

Organic matrix from molluscan shells has the potential to regulate calcium carbonate deposition and crystallization. Control of crystal growth thus seems to depend on control of matrix protein secretion or activation processes in the mantle cells, about which little is known. Biomineralization is a highly orchestrated biological process. The aim of this work was to provide information about the source of shell matrix macromolecule production, within the external epithelium of the mantle. An in vivo approach was chosen to describe the histologic changes in the outer epithelium and in blood sinus distribution, associated with mantle cells implicated in shell matrix production. Our results characterized a topographic and time-dependent zonation of matrix proteins involved in shell biomineralization in the mantle of Haliotis. [ABSTRACT FROM AUTHOR]

Three partial genomic libraries were constructed from genomic DNA of the tropical abalone ( Haliotis asinina) that was digested with AluI, vortexed/sonicated, and digested with mixed enzyme ( AluI, HincII, and RsaI). The libraries yielded 0.02%, 0.42%, and 1.46% positive microsatellite-containing clones, respectively. Eleven clones each of perfect, imperfect, and compound microsatellites were isolated. Ten primer pairs ( CUHas1– CUHas10) were analyzed to evaluate their polymorphic level. The numbers of alleles per locus, observed heterozygosity ( H0), and expected heterozygosity ( He) ranged from 3 to 26 alleles, and varied between 0.27 and 0.85 and between 0.24 and 0.93, respectively. Three microsatellite loci ( CUHas2, CUHas3, and CUHas8) were further used for examination of genetic diversity and differentiation of natural H. asinina in coastal waters of Thailand. Genetic variabilities in terms of the effective number of alleles (ne), H0, and He were higher in 2 samples from the Gulf of Thailand ( ne = 9.37, 7.66; H0 = 0.62, 0.78; and He = 0.87, 0.86) than those of one sample ( ne = 6.04; H0 = 0.58; and He = 0.62) derived from the Andaman Sea. Assessment of genetic heterogeneity, including allele frequency comparison and pairwise FST analysis, indicated interpopulational differentiation, between natural H. asinina from the Gulf of Thailand and that from the Andaman Sea ( P< 0.0001). [ABSTRACT FROM AUTHOR]

The gonad formation, sex differentiation and gonad maturation processes of the abalone, Haliotis discus hannai, are clarified through histological observations on gonads of juveniles artificially produced and reared in tanks. Juveniles were produced in March 1998 and March 1999 and collected from April 1999 to March 2000 periodically (from 1 to 20 months after settlement (AS)), which resulted in observations of 480 abalones with various shell lengths (SL; <2–42 mm). The gonad formation and sex differentiation processes could be divided into four successive phases depending on the appearance of the following histological structures: gonad cavity, primordial germ cells (PGC), chromatin nucleolus stage oocytes (CNO) and maturing germ cells. The gonad cavity started to develop in juveniles over 7 mm SL at 2 months AS. It appeared in the surface connective tissue layer of the growing conical appendage. At 3 months AS, PGC appeared in the gonad cavity of juveniles larger than 7 mm SL. At 7 months AS, in November, sex differentiation was confirmed by the appearance of CNO in females larger than 21 mm SL, but differentiation into males could not be confirmed. From 15 to 18 months AS, from early summer to early autumn, yolk accumulation and spermatogenesis proceeded. Juveniles of both sexes became fully mature in November at about 20 months AS. Besides the germ cell development, several types of non-germ cells were also observed in the gonad cavity: acidophilic granule cells and nuclei strongly stained with hematoxylin in association with the CNO, follicle cells on the stalk of the oocyte at the oil droplet or yolk globule stage, and cells with an elongated nucleus adjacent to spermatogonia in the mature testis. These results on abalone sex differentiation and gonad maturation processes will form the basis for future studies on the effects of endocrine disrupters on such processes. [Copyright &y& Elsevier]

Optimal conditions of 6-dimethylaminopurine (6-DMAP) for triploidy induction in the blacklip abalone Haliotis rubra (Leach, 1814) were investigated, targeting inhibition of second polar body (PB2) formation. Two experiments were conducted at a water temperature of 17.5–18.5°C where factorial combination of (1) four dosages (DSs) of 100, 150, 200 and 250 μM 6-DMAP, four starting times (STs) of 15, 20, 25 and 30 min post fertilization, and two treatment durations (TDs) of 20 and 30 min and (2) three DSs of 50, 100 and 150 μM 6-DMAP, three STs of 15, 20 and 25 min post fertilization, and three TDs of 10, 20 and 30 min, were applied respectively. Day 3 larvae were sampled for triploidy and survival. Percent triploidy was verified using flow cytometry (FCM). Results show that optimal inductions that combine both high rates of triploidy and reasonable survival were those treatments commenced 15 or 20 min post fertilization and continued for 20 or 30 min, using 100 μM 6-DMAP. These conditions induced rates of triploidy and relative survival of 80.5–93.3% and 36.5–40.2%, respectively, in the first experiment, and corresponding rates were 79.1–93.6% and 20.7–43.0% in the second experiment. High percent triploidy were also obtained in a number of treatments using 150 μM 6-DMAP, but with overall survival rates generally lower than those using 100 μM 6-DMAP. [ABSTRACT FROM AUTHOR]

The effectiveness of cytochalasin B (CB) treatments for inducing triploidy was evaluated in the blacklip abalone Haliotis rubra (Leach, 1814) in two orthogonal design experiments. The first experiment employed three dosages (DSs) of 0.25, 0.5 and 1.0 mg CB L−1, three starting times (STs) of 5, 15 and25 min post fertilization and three treatment durations (TDs) of 10, 20 and 40 min, for a total of 27 treatments. The second experiment comprised of two DSs of 0.25 and 0.5 mg CB L−1, five STs of 5, 15, 20, 25and 30 min post fertilization, and three TDs of 10, 20 and 40 min, for a total of 30 treatments. Water temperature was held at 17.5–18.5°C. Day 3 larvae were sampled for triploidy using flow cytometry (FCM) and survival. Optimal inductions were treatments starting at 15 or 20 min post fertilization and continuing for 40 min, and those initiated 25 or 30 min post fertilization for 20 or 40 min, using 0.5 mg CB L−1. These treatments were all targeted at inhibition of the second polar body (PB2) formation and yielded triploidy rates of 84.8–89.5% coupled with (relative) survival rates of 20.1–52.1% in the first experiment, and corresponding rates of 86.5–96.5% and 33.0–74.1%, respectively, in the second experiment. A common and essential feature of these optimal conditions is that treatment must fully span the period of time for most of the eggs to extrude PB2. Treatments that resulted in suppression of the first polar body (PB1) formation induced triploidy levels below 71.5% and 57.6% in experiments 1 and 2 respectively. Treatments that had overlapping effects on both PB1 and PB2 extrusion led to triploidy rates above 80% but very low survival rates of 1.8% and 5.4% in experiments 1 and 2 respectively. [ABSTRACT FROM AUTHOR]

Examines the preferred hole shape and size of abalone, Haliotis sieboldii in Korea. Basis on the design of the shape and size of holes for abalone shelters; Preference of square and triangular holes by majority of the abalones; Causal factor for the lower concentration of abalone in circular holes; Tendency of abalone to gather on a hole that is twice as large as their shell length.

Anna Meyer published her first (and apparently last) scientific paper in 1913, in which she reported, in part, on the organization of the renogenital systems in the "Diotocardia" and "Monotocardia," and the evolutionary signal present in this character suite. Meyer's phylogeny broke with conventional wisdom of her time and she reconstructed early gastropod evolution as a sequence of branching events rather than a continuous grade. Her phylogeny was ignored because it did not correspond to the well-ordered grades that came to dominate gastropod systematics for over 75 years, but her schematics of renogenital configurations have been featured in the literature for over 55 years, sometimes without citation and redrawn to show a different set of relationships. We hope that the translation of her paper from German into English (http://www.ucmp.berkeley.edu/collections/archdat.html) will make her contribution more accessible to workers. [ABSTRACT FROM AUTHOR]

Patella vulgata is one of the most common limpet species on rocky shores throughout the north-eastern Atlantic. Foraging activity of this species has been described during various different diel and tidal phases and several factors have been suggested that might influence the timing of its activity. Among these, inclination of rock surfaces seems to have a clear role, with limpets on horizontal rocks being active during daylight at high water, while limpets on vertical rocks were active during night-time low water. However, by comparing the results of previous investigations it is difficult to separate clearly the effect of any single factor from the effects of their interactions. In the present paper we investigated the simultaneous influence of height on the shore, slope of rock surface and date of sampling (August–September and March–April) on the behaviour of a population of P. vulgata on the Isle of Man (UK). The study was carried out using modern telemetric methods, allowing the activity patterns of limpets to be recorded for long periods of time. The results showed that limpets concentrated their activity during two distinct temporal windows—daytime tide-in and night-time tide-out—while no significant activity was observed during daytime tide-out or night-time tide-in. The observed behaviour appeared to be driven by complex interactions among the three factors examined, and the influence of rock slope alone was not so strong as to override the effect of other factors completely. In addition, a key finding of this study was the conspicuous variability in the individual behaviour of P. vulgata. The greatest level of variability was observed in limpets on vertical surfaces on the upper shore, which showed an extreme switch in behavioural patterns, according to date of sampling (daylight/tide-in foraging during the spring and night-time/tide-out foraging during late summer). In addition, individuals apparently sharing the same set of conditions (inclination, height on the shore and sampling date) differed in their behaviour, and a given behavioural pattern was not always shared by all individuals from a given group. Finally, variability was also observed at the ‘intra-individual’ level since the same individual could be active during different tidal and diel phases. In conclusion, although the existence of endogenous rhythms has previously been demonstrated in this species, our data clearly show that P. vulgata was able to modulate its behavioural patterns in relation to a variety of exogenous determinants. [ABSTRACT FROM AUTHOR]

Heavy infestation by the shell-infesting sabellid, Terebrasabella heterouncinata, has been shown to cause a reduction in the growth rate and marketability of cultured abalone. This worm is endemic to South Africa and the locally cultured abalone, Haliotis midae, are under constant threat of infestation. An understanding of factors that influence abalone growth and sabellid infestation levels under intensive culture conditions is therefore imperative to controlling infestation levels. Abalone were held on an abalone farm at stocking densities of 18%, 23% and 28% of the surface area available to the abalone. They were fed kelp or a pelleted diet, Abfeed™. Their growth and infestation levels were monitored for 14 months. Within the range of abalone sizes used for this study kelp-fed abalone grew significantly better than Abfeed™-fed abalone (F1,197=7.99; P≤0.005), while stocking density had no effect (F2,196=1.41; P≤0.246) on growth. Abalone that became infested grew at the same rate as those that did not (0.09≤P≤1). No growth-limiting effect of infestation was detected. There was no effect on total intensity (i.e., the total number of worms per sample of 60 abalone; 0.41≤P≤1 and 0.17≤P≤1), or prevalence (i.e., the percentage of infected abalone within a sample; 0.50≤P≤1 and 0.19≤P≤1) of infestation by diet and stocking density, respectively. There was a significant positive coefficient of correlation of 86.2% between the level at which an increase in total intensity starts, and the average increase in total intensity per day (F1,10=62.2; P≤0.0001). A regression model is presented to estimate total intensity based on prevalence. The greatest increase in total intensity levels coincided with the onset of spring, and a possible seasonal component to the reproduction of this sabellid is discussed. [Copyright &y& Elsevier]

In 1996 and 1998, a collection of gasteropods was made in the Agua Blanca State Park in order to establish their taxonomic identity and geographic distribution. From this collection, 23 species (1 freshwater and 22 terrestrial) were found to be Prosobranchia (26.1%) and Pulmonata (73.9%). For the Prosobranchia specie, half of them were observed to be Mesogastropoda and the other half Archaeogastropoda; while the Pulmonata specie was encountered to have 100 % of Stylommatophora. The specie's richness was 23. The geographic distribution of the species, restricted to the Mesoamerican Neotropical region, was the main zoographic component with 78.3% (43.5% Mesoamerican Neotropical species with the addition of 34.8 % Mexican Neotropical endemics). The endemic species of Mexico represented 40%, from which 8 % were endemic to Tabasco. [ABSTRACT FROM AUTHOR]

Marine invertebrate species have usually been overlooked in favor of high-profile vertebrate species for facilitating dialogue towards area conservation. The northern abalone (Haliotis kamtschatkana) is proposed as a focal ("flagship") species whose protection and recovery could concentrate public concern for abalone and its associated kelp forest ecosystems in Haida Gwaii (Queen Charlotte Islands), British Columbia. I explain how issues of culture, commerce, and conservation unite to create a strong role for northern abalone in preparations for creating a large marine conservation area within Haida Gwaii. Culture is relevant, as local indigenous people (the Haida) are currently denied access to constitutionally established subsistence fishing rights for northern abalone. Commerce is involved as ongoing kelp forest-associated fisheries co-occur with northern abalone. Finally, this is a challenging precedent in Canadian marine conservation, as restoring two "listed" species­ at risk (northern abalone and their predator, the sea otter (Enhydra lutris)) is potentially mutually exclusive. As part of the forthcoming public consultations towards establishing a marine conservation area, the opportunity provided by northern abalone to focus ideas and values should be seized. [ABSTRACT FROM AUTHOR]

The effect of a formulated diet (FD), a seaweed diet (SW), and a mixture of both (FD + SW) on growth, survival rate, and fatty acid content in the tissue of juvenile Haliotis fulgens abalone grown under commercial culture conditions, was analyzed over a 329-day period. Survival and growth rate in terms of length and weight were different with each of the diets evaluated, being significantly higher (P < 0.05) with the mixed diet (FD + SW), followed by SW and FD. Since feed intake was not evaluated in this preliminary study, differences in growth cannot be attributed to the dietary treatments; however, the importance of this work was to show the significant impact of the diet treatments on the tissue fatty acid profiles, suggesting that the treatments contribute to the composition of some fatty acids found in muscle. The polyunsaturated fatty acid (PUFA) 22:4n-6 was not detected in any of the diets, while 20:4n-3 was only present in SW and 22:5n-3 only in FD. However, after the feeding experiment all these PUFAs were present in abalone tissue. The possible synthesis of PUFAs from dietary n-3 and n-6 fatty acids of shorter hydrocarbon chain is discussed. [ABSTRACT FROM AUTHOR]

Microsatellite markers have been developed for a variety of abalones, and locus-specific homozygote excesses at population level have been recorded for microsatellite loci. To ascertain whether null alleles exist at microsatellite loci in the Pacific abalone, we studied the mode of inheritance of 7 microsatellite loci in 4 families with a reciprocal cross of 2 females × 2 males. All loci segregated codominantly, but only 3 loci (Hdh1321, Hdh78, and Hdd108C) conformed to Mendelian segregation and can be used for parental analysis and population genetic studies. When null alleles were considered, 2 loci (Hdh1761 and Hdh1457) confirmed Mendelian expectations in all families, while the remaining 2 loci (Hdd114B and Hdd229) showed deviation from Mendelian segregation in at least one family even though null alleles were considered. These results indicated the need to test the inheritance pattern for microsatellite markers in abalones before using them for population genetic or parentage analysis. [ABSTRACT FROM AUTHOR]

Focuses on a study which investigated the metabolic rates and use of biochemical reserves in the larval development of two species of abalone. Materials and method; Results; Discussion.

POU-IV genes regulate neuronal development in a number of deuterostomes (chordates) and ecdysozoans (arthropods and nematodes). Currently their function and expression in the third bilaterian clade, the Lophotrochozoa, comprising molluscs, annelids and their affiliates, is unclear. Herein we characterise the developmental expression of HasPOU-IV in the gastropod mollusc, Haliotis asinina . The POU-IV gene is transiently expressed in 11 distinct larval territories during the first 3 days of development. HasPOU-IV is first expressed in sets of ventral epidermal cells in the newly hatched trochophore larvae. As larval morphogenesis proceeds, we observe HasPOU-IV transcripts in cells that putatively form a range of sensory systems including chemo- and mechanosensory cells in the foot, cephalic tentacles, the ctenidia, the geosensory statocyst and the eyes. By comparing HasPOU-IV expression with POU-IV genes in other bilaterians we infer that this class of POU-domain genes had an ancestral role in regulating sensory cell development. [ABSTRACT FROM AUTHOR]

Clithon retropictus is a prosobranch snail species that reproduces in freshwater but spends its veliger period in the sea. The age distribution of this snail was investigated at three sites along Takase River in Japan by counting annual growth lines on their shells. Also, copulation performance was examined using sheaths of spermatophores stored in the bursa copulatrix of females. A mark–recapture census demonstrated that the number of growth lines was a good indicator of the age of a snail. The maximum number of growth lines was 20, suggesting that this species is one of the most long-lived freshwater gastropods. All the populations were female biased; the growth rate was higher and the life span was longer in females. Because spermatophore sheaths received by a female remained in her bursa copulatrix without being digested or discharged, the number of spermatophores implies her lifetime number of copulations. The number ranged from 0 to 91 and increased with age. Comparisons of population demonstrated that the average age was older, and the lifetime copulation number was significantly lower, at the upper stream site. These findings suggest that upstream migration had occurred only when the snails were very young and that copulation had been suppressed at the upstream site. The observed shorter longevity in males and the female-biased sex ratio are thought to be a result of the high cost paid by the male in multiple copulation. [ABSTRACT FROM AUTHOR]

1. The Chilean rocky coast has been exploited for food by coastal gatherers for at least 8500 years BP and probably was an important factor in how prehistoric people were able to colonize the South Americas Pacific Rim. The main species targeted in the past were the same as those today except that now the gatherers are resident and the fishing activity is more intense and persistent. 2. With many pertinent studies from around the world having been published on this topic, mostly conducted in Marine Reserves, this review tries to identify the main patterns that can help us recognize, in the Chilean intertidal, the degree of exploitation on wave exposed and wave protected rocky shore habitats. 3. Three clear patterns were identified depending on the trophic level adopted by the human gatherers in the food chain of the intertidal zone. First, when the humans act as herbivores, collecting the large laminarian Durvillaea antarctica, adult plants disappear from the accessible sites, especially the midlittoral, semi-exposed and exposed habitats. 4. Second, when humans harvest the ecologically important herbivorous archeogastropoda Fissurella spp., this results in the red alga Mazzaella laminarioides covering almost 100% of the midlittoral rocks. Third, when humans become top predators by collecting the muricid carnivore Concholepas concholepas, then bivalves, mainly Perumytilus purpuratus, cover the rocks in multiple layers. 5. These patterns contribute to the evaluation of the state of conservation of the Chilean rocky intertidal shores, especially because the north and the south are beginning to be connected by a new coastal road. Thus it is necessary to evaluate urgently, on a large spatial scale, the state of conservation of these communities, in order to help select the appropriate places for establishing Marine Reserves. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]