Aspects of the ecology and population genetics of the bivalve Corbula gibba

Abstract

The bivalve mollusc Corbula gibba (Olivi) is often regarded as an invasive weed species that forms monospecific stands in organically enriched hypoxic habitats. However, despite its status as a potential menace, surprisingly little is known about its basic biology, including its dispersal capacity. Measurement of the respiration rate of C. gibba revealed a respiratory demand of 3.12 µl O 2 h -1 and a respiratory quotient of 0.61, which suggests that C. gibba adopts a conservationist rather than exploitative mode of life. Examination of the hypoxic tolerance of C. gibba determined that adults could survive for > 34 d (LT 50 ≥ 34 d) and juveniles for > 30 d (LT 50 = 14 d), indicating that this species is well adapted to living in low oxygen habitats. Unusually, adults under hypoxia had a greater survival rate than control adults in normoxic conditions. Investigation of the salinity tolerance of C. gibba revealed that it could readily survive for 2 d at 0 to 16 psu, with increasing mortality for up to 10 d. In brackish seawater, survival was indistinguishable from that in normal seawater. Examination of the population genetics of 6 different populations of C. gibba separated over various spatial scales, using RAPD PCR methodology, determined that all populations were genetically distinct from each other, including populations separated by as little 5 km, although this may in part be due to the influence of a localised front. This suggests that the larval longevity and dispersal capacity of C. gibba is much less than has been previously considered. In light of all the results, it is concluded that instead of being an insidious pest species, C. gibba is more likely to be an inferior competitor, present in background numbers in normoxic habitats, and only becomes dominant when a system becomes hypoxic, thereby removing competitors and allowing C. gibba to flourish in the habitat to which it is adapted.

The Relationship between Mollusks and Oxygen Concentrations in Todos Santos Bay, Baja California, Mexico

“…In our study, genera Natica and Acteocina were collected in high oxygen concentrations in the north and central sections of the bay (stations 1, 3, 9, 4, 13, 14, 19, and 21). Although mollusks have been extensively employed in bioaccumulation studies for metal pollution [7,8,31], other studies have evaluated their utility as indicator of oxygen depletion in coastal environments [53,[55][56][57]. We acknowledge that only four genera of the thirteen dominant mollusks collected at TSB were related significantly to DO concentrations by a negative binomial GLM, which means that Truncatella, Donax, Bulla, and Acteocina follow a natural gradient of DO in Todos Santos Bay, Baja California.…”

Strong genetic differentiation among east Atlantic populations of the sword razor shell (Ensis siliqua) assessed with mtDNA and RAPD markers

“…Among them, RAPDs (Welsh and McClelland 1990) allow a fast and convenient way to unravel the genetic diversity in species without a previous knowledge of the genome and have been extensively used to evaluate the population structure in molluscs (e.g. Huang et al 2000;Holmes et al 2003;Toro et al 2004;Casu et al 2005;Barreiro et al 2006;Holmes and Miller 2006). Similarly, the analysis of mitochondrial DNA has been useful in determining the genetic population structure of molluscan species (e.g.…”

Tolerance of the bivalve <i>Trapezium liratum</i> (Reeve, 1843) to decrease in salinity

“…Some of these bivalves are reported to tolerate sharp decreases in salinity. For example, C. gibba, A. stutchburyi, P. australis, and M. charruana survived >4 days after the ambient water had been replaced with freshwater (Holmes & Miller 2006, McLeod & Wing 2008, Yuan et al 2010.…”

“…The animals studied include many bivalve species: Atrina maura (Sowerby, 1835) (Leyva-Valencia et al 2001), Austrovenus stutchburyi (W. Wood, 1828) (Marsden 2004), Nodipecten nodosus (L., 1758) (Rupp & Parsons 2004), Corbula gibba (Olivi) (Holmes & Miller 2006), Ruditapes philippinarum (Adams & Reeve, 1850) (Matsuda et al 2008), Paphies australis (Gmelin, 1791) (McLeod & Wing 2008), Macoma balthica (L., 1758) (Jansen et al 2009), Mytella charruana (d Orbigny, 1842) (Yuan et al 2010), Atrina lischkeana (Clessin, 1891) (Yamamoto & Handa 2011), etc. Some of these bivalves are reported to tolerate sharp decreases in salinity.…”