Browsing by Author "Capinpin Jr., Emmanuel C."
ArticleThe growth rate of Haliotis asinina fed three diets was evaluated over a 120 day period. Juveniles fed the red alga Gracilariopsis heteroclada and an artificial diet grew faster in terms of both total body weight and shell length than those fed the red alga Kappaphycus alvarezii. Juveniles fed the artificial diet produced more weight than those fed G. heteroclada for the first 90 days, but abalone fed G. heteroclada grew faster from Day 105 onwards. In terms of shell length, the artificial diet produced faster growth rates than G. heteroclada for the first 75 days but from Day 90 onwards, faster growth rates were observed in juveniles fed G. heteroclada. Reductions in daily growth rates of juveniles during the latter phase of the growth trial were attributed to channelling of energy into gonad development. G. heteroclada promoted high growth rates over a long-term period (360 days) and is considered to be best suited for abalone farming in the Philippines.
ArticleThe sex ratio, initial size at sexual maturity, spawning period, time interval between successive spawnings and fecundity of the Donkey's ear abalone, Haliotis asinina were studied. The sex ratio of wild abalone (>60 mm shell length) collected from Panagatan Cays, Antique, Philippines was approximately 1:1. Sexual maturity was first attained at a size of 35.0 mm and 35.9 mm for hatchery-reared male and female abalone, respectively, and 40.6 mm for wild-caught male and female specimens. Based on calculated gonad bulk indices and histological observations, wild-caught abalone appeared capable of spawning during most months of the study period except June for males and May–June for females, during which most specimens collected were at a resting stage. This abalone species is a serial spawner with an asynchronous spawning behavior. Hatchery-reared abalone have short time intervals between successive spawnings of 13–15 days. Ripe females measuring 58.1–69 mm in shell length may release about 150,000 to 600,000 eggs per spawning.