Asian clams: Reduce oxygen in the water

Overall effectiveness category Unlikely to be beneficial
Number of studies: 1
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How is the evidence assessed?

Effectiveness

10%
Certainty

50%
Harms

not assessed

Calculating overall effectiveness category

Background information and definitions

Very low levels of oxygen in the water for a prolonged period may kill Asian clams Corbicula spp. However, even mild reductions in oxygen may offer advantages by increasing the vulnerability of the clams to predation. When attacked, bivalves protect their soft tissues by closing their protective valves. This reduces vulnerability to small predators, but ventilation and oxygen uptake are suspended. In a laboratory study it was found that after a simulated attack, Asian clams under low oxygen conditions reopened their valves sooner than clams under high oxygen conditions, suggesting that low oxygen levels increases vulnerability to predation (Saloom & Duncan 2005).

Saloom M.E. & Duncan R.S. (2005) Low dissolved oxygen levels reduce anti-predation behaviours of the freshwater clam Corbicula fluminea. Freshwater Biology, 50, 1233-1238.

Study locations

Key messages

A controlled laboratory study conducted in the USA found that Asian clams were resistant to extreme very low levels of oxygen, irrespective of water temperature or length of immersion in the test conditions.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A controlled laboratory study in 1999 on specimens from a dam and artificial stream in Texas, USA (Matthews & McMahon 1999) found that Asian clams Corbicula fluminea survived low oxygen levels for extended time periods. They survived an average of 12, 35 and >84 days at 25°C, 15°C and 5°C, respectively. Survival rates were comparable with the control (normal oxygen levels). However, larger clams were less tolerant to low oxygen than smaller ones. Groups of clams were acclimated to 5°, 15° or 25°C for 14 days. A group of 30 adult clams were held in water that was either aerated (control) or had reduced oxygen at 5°, 15° and 25°C. In low oxygen treatments, partial pressure of oxygen was reduced to less than 5% of full air saturation by continually bubbling the water with nitrogen. The water was changed every 2-3 days. Testing ceased when all clams had died or after a maximum of 12 weeks. Oxygen concentrations and survival of clams were recorded daily.
Study and other actions tested
Referenced paper
Matthews M.A. & McMahon R.F. (1999) Effects of temperature and temperature acclimation on survival of zebra mussels (Dreissena polymorpha) and Asian clams (Corbicula fluminea) under extreme hypoxia. Journal of Molluscan Studies, 65, 317-325.

Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Some Aspects of Control of Freshwater Invasive Species. Pages 555-87 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Control of Freshwater Invasive Species

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