Characterizing egg quality and larval performance from captive mahi-mahiCoryphaena hippurus(Linnaeus, 1758) spawns over time

Abstract

Mahi-mahi Coryphaena hippurus is a promising species for aquaculture development and has been used as a model species for oil toxicology and physiology studies. This species has one of the fastest growth rates of any marine teleost and a unique reproductive biology due to its high spawning frequency and reproductive energy allocation. These characteristics lend the species to being an excellent model for understanding broodstock nutrition for other high energetic pelagic species. In this study, egg morphometrics and larval survival were tracked over a 10-week period from the initial capture of wild mahi-mahi broodstock. Larval quality from subsequent spawns collected over time was quantified using larval survival activity indices (SAIs) as a metric to assess egg quality. Larval SAIs were maintained and did not significantly decrease (p < .05) over the time course of this study. A multiple linear regression based on the elapsed time in captivity of the broodstock, egg diameter and larval SAI at 1 dph provided the most accurate prediction of larval SAI at 3 dph (R 2 = 0.996 p < .05). There were strong positive correlations with larval SAIs at 1 and 3 dph and the key nutrients: eicosapentaenoic acid (C20: 5n-3, EPA) and related fatty acid ratios, vitamin E and nearly all amino acids under investigation. This study demonstrated that larval survival was maintained over time due to the supply of these key nutrients in the broodstock diet. K E Y W O R D Sbroodstock, egg quality, mahi-mahi, survival activity index, vitellogenesis

Mahi‐mahi (Coryphaena hippurus) life development: morphological, physiological, behavioral and molecular phenotypes

“…Following fertilization, mahi eggs are approximately 1.2 to 1.6 mm in diameter (Figure A). The eggs contain a single oil globule measuring 257 to 307 μm in diameter, depending on the captivity time . While no standardization exists in the embryogenesis staging of teleost fishes, major molecular and cellular processes that underlie early development are highly conserved across teleost fishes.…”

“…Spawning occurred volitionally (noninduced) at a sex ratio of 1 male:8 females using standard UMEH methods . Spawning events occur naturally throughout the year at UMEH between 2 am and 5 am before sunrise.…”

“…Spawning events occur naturally throughout the year at UMEH between 2 am and 5 am before sunrise. Brood stock spawned naturally every day, with multiple females spawning asynchronously on opposing days . Spawning patterns are relatively time‐specific in order to maintain consistent hatching periods (during the night), which is thought to maximize early larval survival.…”

“…The nutritional composition of the natural diet and dietary supplements is further described in Stieglitz et al 7 Spawning occurred volitionally (noninduced) at a sex ratio of 1 male:8 females using standard UMEH methods. 14,32 Spawning events occur naturally throughout the year at UMEH between 2 AM and 5 AM before sunrise. Brood stock spawned naturally every day, with multiple females spawning asynchronously on opposing days.…”

“…Aside from the interest in this species from a food‐fish perspective, mahi has been identified as a promising candidate for research investigations. Indeed, during the last few decades, mahi has become an emergent model for examining population genetics, developmental physiology, metabolic responses, nutritional physiology, egg and larval performance over time, and climate change effects . Mahi have also been studied extensively regarding the impact of environmental toxicants .…”