World Congress of Malacology Antwerp ... - Unitas Malacologica

We have used mitochondrial COI DNA and nuclear ITS sequences to infer the pattern of genetic
diversity in M. herderiana inhabiting the southern shore of the lake Baikal. We have analyzed thirty
samples from two localities (five hundred meters distant from each other). In one of them ribbed and
smooth shell morphs were sympatric. In the other only the ribbed shell morph was represented. The
observed proportions of nucleotide substitutions among M.herderiana DNA ITS sequences were 0.0 –
1.3% (average 0.18%) and among mtDNA COI sequences were 0.0 – 0.16% (average 0.075%). We
did not reveal any significant correlation between the shell sculpture and the genetic differentiation.
At the current, initial stage of this study it is still not clear what in particular causes the shell sculpture
variation of the M. herderiana: whether it is an effect of the phenotypic plasticity under
environmental conditions or the process is driven by the natural selection.
The study was partially supported by RFBR 05-04-97258.
The effect of diet on reproduction and energy storage in adult mussels Mytilus galloprovincialis
Fearman, Jo-Anne; Moltschaniwskyj, Natalie; Bolch, Chris
School of Aquaculture, Tasmanian Aquaculture & Fisheries Institute, University of Tasmania,
Launceston, Tasmania, 7250,
Email: jfearman@utas.edu.au; Natalie.Moltschaniwskyj@utas.edu.au; chris.bolch@utas.edu.au
Food quality and quantity is known to influence reproduction in many bivalve species. In a hatchery
context, reproduction begins with broodstock conditioning, where adults are held and conditioned for
spawning by supplemental feeding with cultured microalgae. This process is vital for the reliable
production of juvenile bivalves for aquaculture, including mussels, yet the influence of different
microalgal diets on conditioning and energy storage has not been investigated. In this study, adult
mussels were conditioned for six weeks with four different feeding regimes: 1) raw seawater; and,
raw seawater plus equivalent dry weights of 2) Chaetoceros calcitrans, 3) Pavlova lutheri, and 4) a
1:1 combination of the two species. The conditioning diet had a significant effect on the quantity of
glycogen stored and the reproductive status at the end of six weeks. Mussels fed with raw seawater
showed reduced glycogen stores, and a low percentage of mussels that spawned. Those supplemented
with P. lutheri maintained mature eggs and produced an intermediate percentage of animals that
spawned. However, they showed reduced glycogen stores, and produced a low number of D-veliger
larvae from the eggs. Mussels supplemented with C. calcitrans increased glycogen stores, maintained
mature eggs and produced an intermediate number of animals that spawned. They also produced a
high number of D-veliger larvae, similar to the combined supplement. The combined C. calcitrans
and P. lutheri supplement showed no change in glycogen stores after 6 weeks, but this likely
reflected more rapid glycogen accumulation followed by mobilization into gonad tissue, resulting in a
high percentage of animals that spawned, and a high production of D-veliger larvae from eggs. Egg
diameter, a measure of egg quality, and fecundity showed no significant difference amongst diets.
The scientific and applied implications of these results are discussed in relation to previous research.
First case of the radular-less representatives of the subfamily Crassispirinae (Turridae) with
critical reassessment of the taxonomic status of the subfamily Zemaciinae (Turridae)
Fedosov, Alexander
A.N.Severtzov Institute of Ecology and Evolution of Russian Academy of Sciences, Leninskij pr. 33,
Moscow, 119071, Russia,
Email: fedosov_zool@mail.ru
Superfamily Conoidea is well known for the unique, ‘toxoglossan’ mode of feeding with usage of the
separate marginal radular teeth on the proboscis tip for stubbing and envenomation of the prey. In
some groups of Conoidea (Terebridae and subfamily Raphitominae of Conidae) the tendency to
reduction and complete loss of radular, venom apparatus and other foregut structures has been
demonstrated.
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