Article info.

ABSTRACT

Received 25 Sep 2018
Revised 12 Jan 2019

Accepted 30 Jul 2019

Different stocking densities and feed types were evaluated in rearing larvae of mud clam Geloina sp. The experiment 1 included four feed treatments as (i) 100% fresh algae (Nannochloropsis sp and Chaetoceros sp with 1:1 ratio), (ii) 100% dry algae (Spirulina powder), (iii) 75% fresh algae + 25% dry algae, and  (iv) 50% fresh algae +50% dry algae. Mud clam larvae were cultured in 5L bottles at the stocking density of 2,000 larvae/L. Experiment period was lasted 17 days from D-larvae to umbo stage (from planktonic to benthic stage). Experiment 2 included three treatments with different nursing densities of clam larvae from (i) 2,000 larvae/L, (ii) 4,000 larvae/L to (iii) 8,000 larvae/L. The best feed type from experiment 1 was applied for feeding in experiment 2. Results from experiment 1 showed that in treatment with 100% fresh algae, the length and width of larvae reached highest values (217.3µm and 230.0 µm) on day 17. In this treatment, metamorphosis rate (31.2%), survival rate (10.5%) and larvae production (300 ind./L) also reached higher values than in other treatments (p<0.05). In experiment 2, the best result was obtained when nursing clam larvae at 2,000 ind./L. Length and width of larvae reach highest values (218.3µm and 231.3µm on day 17, respectively), metamorphosis rate (34.9%), survival rate (10.3%) and larvae production (294 ind./L) were  also highest in this treatment.

Keywords

D-larvae, density, Geloina sp., micro algae, mud clam

Cited as: Thao, N.T.T., Nhiet, D., An, C.M. and Hai, T.N., 2019. Growth and survival rate of mud clam larvae (Geloina sp.) in relation to rearing densities and diets. Can Tho University Journal of Science. 11(2): 89-96.