Grow-out culture of the abalone Haliotis asinina in Guimaras, Philippines: comparison of tubes and drums as culture containers and the effects of serpulid infestation

Abstract

This study compared tubes and drums as containers for the grow-out culture of abalone Haliotis asinina using mixed seaweeds and formulated diet as feed. The recycled drums were newly tested containers for abalone culture as the cheaper and larger alternative. However, on the 10th month of culture, serpulids (Pomatoceros sp. and Spirorbis sp.) were observed on the abalone shells; hence, the 12-month culture was extended to 16 months to observe further the effects of these ectoparasites on the growth and survival of abalone. Throughout the culture period, abalone reared in tubes had significantly higher mean shell length and body weight than those reared in drums, measuring 45.42 ± 0.36 mm, 23.40 ± 0.99 g, and 41.45 ± 0.23 mm, 18.26 ± 0.40 g at harvest, respectively. Mean growth rates of those in tubes were significantly higher than those in drums before serpulid infestation but did not differ during months of infestation. Survival was consistently higher in tubes than drums, except during May–September 2023. At harvest, survival in tubes was 46.7 ± 11.0%, 37.8 ± 5.9% in drums. Daily water temperature ranged 28.00–32.33 °C, salinity 16.00–34.37 ppt. Monthly readings (ppm) of dissolved oxygen ranged 3.1–7.4, sulfide 0.00–0.73, phosphate 0.01–0.87, nitrate 0.00–0.99, nitrite 0.00–0.22, and total suspended solids 0.22–4.83. In April–October 2023, serpulids became prevalent (tubes = 31.5 ± 3.4%; drums = 38.3 ± 3.4%) when mean DO was significantly lower and sulfide higher than in June 2022-March 2023. These fluctuations in water parameters may have triggered the infestation, resulting in lower growth rates and abalone survival. But, despite these fluctuations and infestations, tubes remained a better culture container for the abalone.