Although four studies have provided limited data on the food habits of dolphinfishes in coastal areas of the eastern Pacific Ocean (EPO) (Hida, 1973; Campos et al., 1993; Aguilar-Palomino et al., 1998; Lasso and Zapata, 1999), little is known of the predation dynamics of dolphinfishes over the majority of their oceanic habitat.
The time-course of gastric evacuation has not been adequately described for dolphinfishes. This fact prevents a rigorous analysis of consumption rates using stomach-contents data.
Many of these prey were flyingfishes, cephalopods, dolphinfishes, wahoo, and snake mackerel in digestion states 3 or 4 and were found in stomachs that were over 50% full.
Fish prey, such as flyingfishes, dolphinfishes, wahoo, and snake mackerel, would need to be ingested during nighttime hours to reach digestion states 3 or 4 before 09:00 hours the next morning, as we observed in our study, unless gastric evacuation rates are much faster than expected.
Maximum prey size is determined by the mouth gape of the predator (Magnuson and Heitz, 1971; Hambright, 1991), and minimum prey size was correlated with the gap width between the gill rakers for a variety of tunas, mackerels, and dolphinfishes (Magnuson and Heitz, 1971).
Nonrecorded annual bycatch for this period was estimated at 944-2270 t of pelagic oceanic sharks, 720-1877 t of rainbow runners, 705-1836 t of dolphinfishes
, 507-1322 t of triggerfishes, 113-294 t of wahoo, 104-251 t of billfishes, 53-112 t of mobulas and mantas, 35-89 t of mackerel scad, 9-24 t of barracudas, and 67-174 t of other fishes.