Effects of egg stocking density on egg hatchability, larval quality and water quality for pinfish, Lagodon rhomboides , and pigfish, Orthopristis chrysoptera

Abstract

Pinfish (Lagodon rhomboides Linnaeus) and pigfish (Orthopristis chrysoptera L.) are relatively new, cultured species commonly used as marine baitfish in the south‐eastern United States and currently have no defined protocols for egg incubation. Thus, experiments were conducted to determine efficient egg stocking densities during static and flow‐through incubation that yielded higher quality larvae. Eggs of each species were incubated statically at 250, 500, 1000 and 2000 eggs L−1, and after incubation, egg hatching success, larval survival to first feeding, larval morphometrics and water quality were assessed. Stocking densities above 250 eggs L−1 led to significant reductions in pinfish hatching success and water quality degradation, evident from decreased dissolved oxygen and pH levels and increased nitrogenous wastes. Increased stocking densities for pigfish also resulted in significant water quality degradation, although hatching success was unaffected up to a density of 1000 eggs L−1. A high flow‐through water exchange rate of 2000% daily resulted in significant reductions in nitrogenous wastes and greater stability in dissolved oxygen and pH levels during incubation when compared to static treatments of the same egg density. Additionally, the high exchange rate of 2000% was critical in maintaining high hatching success and larval survival to first feeding at stocking densities of 1000 eggs L−1 for pinfish and up to 4000 eggs L−1 for pigfish. No clear patterns in larval morphometrics were observed among stocking densities. Static incubation densities of 250 and 1000 eggs L−1 are recommended for pinfish and pigfish, respectively.

CO2 induced seawater acidification impacts survival and development of European eel embryos

“…Such scenarios should also be considered in relation to European eel culture. Here, decreasing dissolved oxygen levels and pH during offspring culture can occur as a result of high stocking densities [ 78 ] or microbial activity [ 79 ].…”

Egg Hatching, Stocking, Larval Feeding, and Handling Mortality of Guinean Fingerfish Monodactylus sebae

“…(2015) reported densities of 200–500 eggs/L for Cobia Rachycentron canadum and Florida Pompano Trachinotus carolinus , and Broach et al. (2017) evaluated static stocking densities of 250–2,000 eggs/L for Pinfish Lagodon rhomboides and Pigfish Orthopristis chrysoptera , although the lower stocking densities resulted in a higher hatching success. Commercial producers of Guinean Fingerfish must weigh the costs and benefits of choosing higher hatching success versus the ability to stock more eggs in less space because lower stocking densities will require more tank space and a larger footprint in the hatchery.…”

“…Egg stocking density experiment.-Egg fertilization was believed to occur around sunset, and eggs were stocked by 0900 hours the next morning. Following similar egg incubation methods and the same experimental system described by Broach et al (2017), different egg stocking densities (10, 20, 30, and 40 eggs/L) were visually counted by one person by dipping small numbers into a 10-mL cup and then stocking them at the treatment densities into identical 1-L, clear-plastic containers (top diameter = 11.4 cm; bottom diameter = 8.4 cm; height = 14.6 cm) with the bottom removed and with 100-µm-mesh screen hot glued to the open bottom. The screen-bottomed container was then placed inside of an identical, solid-bottomed container filled with 800 mL of water.…”