Portal de Periódicos da CAPES

Spawning in Trochus maculatus: field observations from Bolinao, Pangasinan (Philippines)

2013; Springer Science+Business Media; Volume: 32; Issue: 4 Linguagem: Inglês

10.1007/s00338-013-1060-y

1432-0975

Elizaldy A. Maboloc, S. Suzanne Mingoa-Licuanan,

Historical Geography and Cartography

Spawning in Trochus maculatus: field observations from Bolinao, Pangasinan (Philippines)The maculated top shell Trochus maculatus inhabits the lower to sublittoral zones in Indo-and South Pacific reefs, feeding on green and red algae and benthic diatoms.As T. maculatus is economically important, e.g., its meat for food and its shell potentially in button making, Thailand has developed culture methods for this species (Chunhabundit et al. 2001).Hatchery rearing of T. maculatus shows spawning during the new and early full moons (Chunhabundit and Thapanand 1993).Literature on natural spawning of T. maculatus is nil.On April 11, 2012, 29 T. maculatus individuals were observed releasing gametes at 0900-1045 hours and 1100-1220 hours, 3 days after full moon, within the Bolinao Marine Laboratory's giant clam ocean nursery (northwestern Lingayen Gulf).Depth was ~2 m, substrata sand-coral, and water temperature ~29.5 °C within summer's ambient range.Current was moderately strong; the tide was high and still rising.The top shells aggregated and perched on Tridacna gigas shells (Fig. 1a,b).Males first released a stream of sperm (Fig. 1a,b), then 3 females, ~1 m away, released eggs ~5 min after sperm release.Aggregation and perching are likely spawning behaviors as top shells returned to crevices later.The average basal diameter of spawned individuals was 3.3 ± 0.2 cm.Spawning of 36 T. maculatus individuals was again observed in the nursery in a smaller area on February 11, 2013, a day after new moon.The top shells spawned from 1430 to 1500 hours.In 2 h, 5 females released eggs.Water temperature was 28 ºC, and again, the tide was rising.Observations were opportunistic, coincident with nursery monitoring, hence, no comparison has been made between rising and ebb tides.Our observations reveal T. maculatus spawning naturally during daytime, at more than one period in the year.The environmental cue for spawning may be a rising tide, 1-3 days after a new or full moon.