Whale shark (Rhincodon typus) seasonal presence, residence time and habitat use at darwin island, galapagos marine reserve.

摘要: The life history of the whale shark (Rhincodon typus), including its reproductive ecology, still remains largely unknown. Here, we present results from first population study around Darwin Island, Galapagos Marine Reserve. Following a diversified approach characterized seasonal occurrence, structure and size, described habitat use sharks based on fine scale movements island. Whale presence at Island was negatively correlated with Sea Surface Temperature (SST), highest abundance corresponding to cool season between July December over six years monitoring. From 2011 2013 photo-identified 82 ranging 4 13.1 m Total Length (TL). Size distribution bimodal, great majority (91.5%) adult female individuals averaging 11.35 m±0.12 (TL±SE), all but one showing signs potential pregnancy. Population dynamics models for apparently pregnant estimated 3.76±0.90 (mean ± SE) in area per day an individual residence time 2.09±0.51 days. Movement patterns analysis four tracked acoustic tags revealed intense Darwin's Arch, where no feeding or specific behavior has been recorded, together periodic excursions island's vicinity. Sharks showed preference intermediate depths (20–30 m) occasional dives mostly mid-water, remaining their water temperatures 24–25°C. All our point as important stopover migration, possibly purposes, rather than aggregation site. Current studies carried out this investigate regional movement may provide essential information about possible pupping grounds enigmatic species.