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  • 1
    Electronic Resource
    Electronic Resource
    High levels of genetic subdivision of marine and estuarine populations of the estuarine catfishCnidoglanis macrocephalus (Plotosidae) in southwestern Australia (1994)
    Springer
    Marine biology 118 (1994), S. 25-31 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cobblerCnidoglanis macrocephalus (Valenciennes) is an endemic marine and estuarine catfish from southern Australia. Conflicting views on the degree of isolation of the estuarine populations underscore general questions about genetic divergence in coastal species. Although estuaries are widely recognized as ecologically important, little work has been done on their role in favouring genetic divergence. In order to estimate the extent of genetic subdivision among nearshore marine and estuarine populations, electrophoretic variation of enzymes was examined in seven marine and six estuarine populations of cobbler from sites spanning 1500 km along the southwest Australian coastline. Among all populations, the mean standardized variance in allelic frequencies (F ST) for six polymorphic loci was 0.277, a high value comparable to those of other shallow-water teleosts whose life-history characteristics and habitat preferences restrict their dispersal capability. The pattern of genetic identities between populations showed divergence between west and south coast sites. Within these regional groups, however, there was substantial heterogeneity, much of which was associated with estuaries. Among all six estuarine sites, the averageF ST was 0.333, 40% higher than the value of 0.237 for the marine sites. Low estimates of the genetically effective number of migrants suggest population subdivision between marine and estuarine environments and between similar habitat types. This study indicates the importance of habitat in affecting the connectedness of populations, even in apparently open marine systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00699216
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  • 2
    Electronic Resource
    Electronic Resource
    The Wahlund effect and the geographical scale of variation in the intertidal limpet Siphonaria sp. (1984)
    Springer
    Marine biology 79 (1984), S. 295-302 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Samples of Siphonaria sp. were collected between 1978 and 1982 from sites covering its known geographic range, from Kalbarri, Western Australia to Port Robe, South Australia. Geographic variation of 7 polymorphic enzymes was examined in this intertidal pulmonate limpet, and was found to be consistently small, indicating a large-scale influence of gene flow due to planktonic dispersal. Despite this large-scale uniformity, there is fine-scale genetic patchiness, which is repeated, rather than accumulated, on the larger scale. Throughout its geographic range, Siphonaria sp. shows deficits of heterozygotes for all 7 loci. The consistency among loci indicates that the causes of the deficits are populational, rather than locus-specific. A Wahlund effect, the departure from Hardy-Weinberg equilibrium due to mixing of individuals from groups with different allelic frequencies, is the simplest explanation of such deficits. The limited geographic variation of allelic frequencies, however, is grossly inadequate to produce these deficits through a Wahlund effect. Similarly, temporal variation in allelic frequencies in recruits does not explain the deficits. The largest contributor to a Wahlund effect appears to be binomial sampling variance among small local breeding groups. Thus, mixing of larvae on a scale of metres, rather than among geographical areas, apparently produces the deficits of heterozygotes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393261
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  • 3
    Electronic Resource
    Electronic Resource
    Relative size of Aristotle's lantern in Echinometra mathaei occuring at different densities (1982)
    Springer
    Marine biology 71 (1982), S. 101-106 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Like species of sea urchins in Zanzibar and Oregon (USA), Echinometra mathaei (de Blainville) at Rottnest Island, Western Australia, displays variation in the size of Aristotle's lantern relative to the maximum diameter of the test. This variation was associated with local variations in density of urchins at each of two sites in each of two years (1980 and 1981); this association with density was consistent with the proposal that relatively larger lanterns are a response to decreased food availability. Furthermore, variation of relative lantern size associated with local density was similar in magnitude to the variation displayed between sites and between years. This temporal variation demonstrated the plasticity of the relative lantern size over periods as short as 12 mo. Further experimental studies are required before relative length of lanterns can be used as estimates of food availability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396997
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  • 4
    Electronic Resource
    Electronic Resource
    Genetic differentiation independent of intertidal gradients in the pulmonate limpet Siphonaria kurracheensis (1981)
    Springer
    Marine biology 64 (1981), S. 79-84 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intertidal limpet Siphonaria kurracheensis (Reeve, 1856) has a bimodal vertical distribution of abundance on rocky shores at Rottnest Island, Western Australia. An electrophoretic study of 5 polymorphic enzymes revealed no consistent genetic differences between adults high and low on the shore. Contrasting with this absence of a detectable genetic response to the steep environmental gradients in the intertidal zone, there were genetic differences among low-shore adults from different sites, and between adults and recruits. This genetic differentiation could be due to either localized selection or temporal variation in the genetic makeup of recruits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394083
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of recruitment on genetic patchiness in the urchinEchinometra mathaei in Western Australia (1990)
    Springer
    Marine biology 105 (1990), S. 145-151 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Enzyme polymorphisms in the sea urchinEchinometra mathaei were examined to test the relative influences of population turnover and patchiness in recruitment on genetic heterogeneity. We found that the total variance in allelic frequency among three populations separated by approximately 4 km at Rottnest Island, Western Australia (collected in February 1985) is as large as that among five additional samples collected over a distance of 1 300 km along the Western Australian coast in August 1987. This suggests that the forces causing genetic differentiation act on a local scale and occur in a single generation. A comparison of sites with different histories of recruitment indicates that the observed genetic differences among age groups are the result of prerecruitment effects, and that differences among sites reflect their individual histories of recruitment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01344280
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  • 6
    Electronic Resource
    Electronic Resource
    High levels of genetic subdivision in peripherally isolated populations of the atherinid fish Craterocephalus capreoli in the Houtman Abrolhos Islands, Western Australia (1994)
    Springer
    Marine biology 119 (1994), S. 179-184 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The atherinid fish Craterocephalus capreoli Rendahl is abundant in the Houtman Abrolhos Islands, 70 km off the Western Australia coast and ≃250 km south of the southern limit of the range of the species along the mainland. Electrophoretic examination of 7 allozyme loci at 17 sites in the Houtman Abrolhos revealed a substantially lower level of polymorphism than found in an earlier study of the species in its mainland distribution, with many of the uncommon alleles and some common ones missing. There is a very high degree of genetic subdivision among the populations in the Houtman Abrolhos, measured by a mean F ST of 0.437 over a distance of 35 km. This F ST (standardized variance in allelic frequencies) is six times that found previously among populations along the mainland coast over distances up to 850 km. The subdivision of populations in the Houtman Abrolhos is similar within one island group on a scale up to 12 km, and between two groups that are separated by 15 km of deep water. Significant differences in allelic frequencies were found between populations from the open shore and enclosed lagoons less than 800 m apart, but the overall levels of subdivision were similar for the two types of environment. Previous work had shown high levels of genetic subdivision in the Houtman Abrolhos for a gastropod with direct development. The results for C. capreoli demonstrate that the archipelago favours subdivision even for a species with potentially much greater mobility and different life history.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349554
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  • 7
    Electronic Resource
    Electronic Resource
    Temporal variation of recruits as a basis of ephemeral genetic heterogeneity in the western rock lobster Panulirus cygnus (1999)
    Springer
    Marine biology 135 (1999), S. 133-139 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Allozymes were examined in quantitative lunar monthly collections of larval recruits of the western rock lobster Panulirus cygnus George over three recruitment seasons at two sites nearly 350 km apart in Western Australia. At Alkimos, the southern site, recruitment occurs in a relatively narrow peak early in the spring, whereas at the northern Houtman Abrolhos Islands, recruitment extends into the summer months. In the 1995/1996 recruitment season, the frequency of the GPI * 100 allele increased from early to late in the season, but the frequencies were indistinguishable at the two sites in each monthly collection. The combination of this temporal variation in allelic frequencies with the contrasting patterns of recruitment at the Abrolhos Islands and Alkimos resulted in genetically different cohorts at the two sites. This pattern was ephemeral, as it was not repeated in the subsequent two years. Thus, ephemeral genetic patchiness in P. cygnus can be generated by the locally-specific genetic mix of recruits obtained from a common larval pool. This mechanism is the probable explanation of previously observed temporal and possible spatial genetic variation in adult P. cygnus, and highlights the importance of studying recruitment in order to understand the genetic structure of marine species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050610
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of isolation by distance and geographical discontinuity on genetic subdivision of Littoraria cingulata (1998)
    Springer
    Marine biology 132 (1998), S. 295-303 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Littoraria cingulata (Philippi, 1846) is a Western Australian, mangrove littorine snail, represented by two morphologically distinct subspecies, whose distributions are separated by 〉300 km. The southern subspecies, L. cingulata pristissini, is distinguished from the northern subspecies, L. cingulata cingulata, by having a thinner, keelless shell with more primary grooves, and lower and much more numerous ribs. In contrast with these striking differences, L. cingulata cingulata is morphologically very similar to another species, L. sulculosa, with which it also shares a nearly coincident geographic range. Allozyme comparisons at 22 presumptive loci confirmed a large genetic distance between L. cingulata and L. sulculosa, and the apparent conspecificity of the morphologically divergent subspecies of L. cingulata. Based on geological evidence, the geographical separation of the morphologically divergent forms of L. cingulata has developed within the past 5000 to 10 000 yr. The extensive continuous distribution of the northern subspecies, L. cingulatacingulata, and the large geographic disjunction between the northern and Shark Bay subspecies, L. cingulata pristissini, allowed a test of the genetic importance of this relatively recent disjunction. Within the continuous distribution of the two subspecies, a pattern of isolation by distance was visible up to distances of 300 km. Beyond 300 km, genetic subdivision, measured by pairwise G ST (the proportion of genetic diversity due to differences between populations), averaged 0.028, whereas subdivision between Shark Bay and northern populations averaged 0.055 over the same range of distances. Although the relative paucity of barriers to gene flow tends to limit genetic subdivision in marine species with planktotrophic larvae, the results for L. cingulata suggest that subdivision can occur within a continuous distribution, but that special events leading to major disjunctions can substantially increase divergence, even over a relatively short period of time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050395
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  • 9
    Electronic Resource
    Electronic Resource
    Association of allozymes and temperature in the crested blenny Anoplarchus purpurescens (1977)
    Springer
    Marine biology 41 (1977), S. 147-152 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The crested blenny Anoplarchus purpurescens occurs intertidally in the Puget Sound area (USA), where it is subjected to substantial variation in temperature. A study of a polymorphic esterase in A. purpurescens has revealed a latitudinal cline and a correlation of allelic frequencies with summer water temperature. This finding agrees with previous results for a lactate dehydrogenase polymorphism in A. purpurescens, suggesting a pervasive genetic adaptation to temperature in this species. For each of these enzymes, comparisons within and between two species of Anoplarchus andicate an association between heterozygosity and temporal variability of the thermal environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394022
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  • 10
    Electronic Resource
    Electronic Resource
    Asexual viviparity and population genetics of Actinia tenebrosa (1979)
    Springer
    Marine biology 53 (1979), S. 27-31 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intertidal anemone Actinia tenebrosa is viviparous. An electrophoretic study of 3 polymorphic enzymes in Western Australian populations has confirmed genetic identity of adults and their brood young, indicating asexual reproduction. The population effects of this clonal reproduction are seen as linkage disequilibrium and departures from Hardy-Weinberg equilibrium within populations, and large differences between populations. The data also suggest occasional sexual reproduction, and the likelihood of a mixture of reproductive modes in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386526
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