Slower growth rates have been recorded in the Danish Sound where it took a population of Corbula gibba seven months to reach a mean size of 1.1 mm (Muss, 1973). Whereas in Port Erin on the Isle of Man it took one year for a population of juveniles to reach a mean size of 4 mm (Jones, 1956, Jensen, 1990). Jones (1956) also reported that the specimens of Corbula gibba on the Isle of Man had a modal length of 2.25 mm. Jensen (1990) suggested that the higher growth rates in the 1990's in Danish waters could be the result of specific events such as eutrophication. However, in Nissum Bredning no specimens were found over two years old in 1990. The size of Corbula gibba around the British Isles ranged from 0.5 mm in length to 1.2 cm in the 1940's (Yonge, 1946), and in Australian waters it can reach sizes up to 1.5 cm (CRIMP, 2000).

Abundance
Corbula gibba is often found in very large numbers and is often abundant in eutrophic areas (Pearson & Rosenberg, 1978). Corbula gibba are known to occur in enormous numbers, for instance 7450/m², at certain localities in the Atlantic (Healy & Lamprell, 1996). In the Limfjord, sampling of Corbula gibba was carried out at monthly intervals from April 1986 to May 1988. Ten samples were taken with a HAPS-corer (0.014 m²) and sieved over a 1 mm sieve (Jensen, 1990). The density for Corbula gibba ranged from 9,000 to around 53,000 per m². Newly settled Corbula gibba ranged from 30,000 and 67,000 individuals per m² (Jensen, 1988). In Pula Harbour in the Northern Adriatic, Corbula gibba was found at densities ranging from 33 -121 individuals / 0.2 m² (Hrs-Brenko, 1981). Corbula gibba is also found in Australia, outside of its native range, at densities of up to 250/m² in Port Philip Bay (CRIMP, 2000).

Biomass / Production
During 1974-1984 nitrogen concentration and primary production of specimens of Corbula gibba in Nissum Bredning increased from 50-100 % and 200-300 %. The production (P) of Corbula gibba is generally high. Productivity was measured over two years and ranged from 0.7-72 g AFDW (ash free dry weight) m²/ yr. with an average of 26.8g AFDW m² / yr. in Nissum Bredning. The production / biomass ratio was amongst the highest recorded with a mean P / B of 4:2 per year (Jensen, 1990).

Respiration
Laboratory studies have shown that Corbula gibba are able to survive long periods at near anoxic conditions. After 57 days, 9 out of 14 specimens survived 10 -11°C and oxygen levels of 0.18 to 0.37 mg oxygen per dm³ (Christensen, 1970).

Burrowing
Corbula gibba is a shallow burrowing bivalve with very short siphons (Yonge & Thompson, 1976). When placed on their normal substratum, individuals extrude their thin long foot to a distance that may exceed the length of its shell (Yonge, 1946). The process of burrowing is very slow. For example, an individual 1 cm long took about 30 minutes to burrow below the surface. This is slow when compared to other bivalve species, for example Abra alba that can disappear below the surface in less than a minute. It is the stout rounded shell that makes slow progress into the substratum, whereas Abra alba has a much flattened shell and foot therefore slides quickly into the substrata (Yonge, 1946).

Predators
Corbula gibba is consumed by gastropods, crustaceans, fish and echinoderms. Predators of Corbula gibba include the necklace shell Natica poliana (Jones, 1956), the sand star Astropecten irregularis (Christensen, 1970), the brittle star Ophiura texturata, the common starfish Asterias rubens, the common shore crab Carcinus maenas and the brown shrimp Crangon crangon (Jensen, 1988).

Non-native species
In Australia, Corbula gibba is an alien species and a pest (CRIMP, 2000). Corbula gibba is now widespread and highly abundant in Port Phillip Bay (Australia) (Talman, 1998; cited in Talman & Keough, 2001). Corbula gibba might affect endemic Australian species via habitat modification, predation on planktonic larvae, and competition. It also possesses a number of characteristics that may give it a competitive advantage over Australian endemic species, such as the capacity for fast growth and the ability to tolerate a wide range of environmental conditions including anoxia and eutrophication (Jensen, 1990; Talman & Keough, 2001). Concern has arisen in Australia regarding the impact of Corbula gibba on the commercial scallop Pecten fumatus. Corbula gibba and Pecten fumatus overlap in distribution, and as suspension feeders, it has been suggested that they utilize similar food and therefore may be competing for space and food (Talman & Keough, 2001). It was found that ambient densities of Corbula gibba had a significant impact on the size and growth of the native juvenile Pecten fumatus but not on mortality rates (Talman & Keough, 2001). Scallops in the presence of Corbula gibba had shells that were, on average, 35% lighter, 24% smaller and exhibited 54% less growth (based on caging experiments) (Talman, 2000: cited in NIMPIS, 2002). As a result of these concerns Australian authorities have developed new methods to control the spread of Corbula gibba. However, measures such as dredging / beam trawling / mopping, changing salinity and oxygen deprivation have all proved relatively unsuccessful (McEnnulty et al., 2001a).

Global distribution
Corbula gibba has spread and outside its native range. This species and its larvae can survive long periods in ballast water and can generate heavy or at least significant populations in foreign harbours. It is most likely that the presence of larvae in ballast water has resulted in the introduction of Corbula gibba into Australian waters in Port Phillip Bay (McEnnulty et al., 2001b). Its occurrence in Port Phillip was the first documented record of the species outside its area of natural distribution (Talman & Keough, 2001). The clam has subsequently been found in Portland, Western Port Bay in Victoria, Devonport and the D'Entrecasteaux Channel in Tasmania (CRIMP, 2000).

Substrata
Corbula gibba is specialized for life in a substratum of muddy sand mixed with larger pieces of gravel and stone that are necessary for the planting of its single byssus thread (Yonge, 1946). This preference for muddy substrata was reported by Jones (1956). Jones (1956) recorded significant differences in the numbers of Corbula gibba between two sites in Port Erin on the Isle of Man. Higher numbers of Corbula gibba were recorded in areas of coarse muddy sand. In an area only 1/2 mile seawards from the previous site the sediments were fine and the numbers of Corbula gibba present were low (Jones, 1956). In the Adriatic Corbula gibba was completely absent in clean, sandy bottoms as it prefers some mud (Hrs-Brenko, 1981).

Preference for coarse muddy sand has also been seen in Port Philip Bay where Corbula gibba are rarely found in sediments that contain less than 10% mud (<63 µm). Below 15% mud there was a strong relationship between the percentage mud and the abundance of Corbula gibba (Parry & Cohen, 2001). Above 15 % mud there was no significant relationship between the abundance of Corbula gibba and percentage mud in the finer sediments (Parry & Cohen, 2001).

Water quality
Hrs-Brenko (1981) suggested that Corbula gibba thrives in eutrophic waters.

Salinity range
Corbula gibba has been recorded at the following salinities, 26 - 39 ppt in Port Phillip Bay (Talman, 2000: cited in NIMPIS, 2002), 28 - 34 ppt in Limfjord, Denmark, (Jensen, 1990), 27 - 32 ppt in Nissum Bredning, Denmark (Jensen, 1988) and 8.2-38.6 ppt in Elefsis Bay, Greece (Theodorou, 1994).