A guide to the embryonic development of the shovelnose sturgeon (Scaphirhynchus platorynchus), reared at a constant temperature

Abstract

Described is the sequence and timing of embryologic development of shovelnose sturgeon, (Scaphirhynchus platorynchus) reared at a constant temperature 20 ± 0.5°C. Artificially spawned, fertilized eggs were held in a recirculating system. Embryos were sampled hourly during the first 48 h of development and every 3 h thereafter. Embryos were viewed and imaged at 35· magnification. The first cleavage furrow appeared 2 h post-fertilization; early (synchronous) cleavage was completed after 7 h. Blastulation concluded at 16 h when the dorsal blastopore lip formed. The slitlike blastopore appeared at 29 h, signifying the completion of gastrulation. At 33 h, the rudiments of the excretory system emerged, followed by closing of the neural tube at 36 h and formation of the s-shaped heart at 60 h. The body continued to elongate with mass hatch occurring at 102 h. After hatch, larvae swam into the water column and drifted in the flow for approximately 2 days after which the larvae became positively rheotaxic. After expulsion of the pigment plug, the larvae began exogenous feeding and other structures continued to develop. Metamorphosis was completed after 26 days of development. Because the shovelnose sturgeon possesses developmental patterns similar to those of other sturgeon, we can use this species as a model for the closely related pallid and Alabama sturgeon.

Sensitivity of shovelnose sturgeon (Scaphirhynchus platorynchus) and pallid sturgeon (S. albus) early life stages to 3,3′,4,4′,5‐pentachlorobiphenyl and 2,3,7,8‐tetrachlorodibenzo‐P‐dioxin exposure

“…Study endpoints focused on quantifying mortality and pathologies at early life stages. Life stages reported throughout are consistent with those previously described for shovelnose sturgeon . All studies were ended at 31 d postfertilization (dpf) to prevent mortality caused by starvation or other nontreatment‐related effects.…”

“…Reduced hatchability in other fish species [30][31][32], including 2 species of Acipenser sturgeon [33], has been related to total PCB or TCDD exposure. Shovelnose sturgeon, and presumably pallid sturgeon, have larger posthatch yolk reserves than some lotic species [22]. Therefore, sequestering of dioxin-like PCBs and dioxin in the yolk may reduce expression of toxicity in pallid and shovelnose sturgeon during this early developmental phase.…”

Is Shallow Water a Suitable Surrogate for Assessing Efforts to Address Pallid Sturgeon Population Declines?

“…For example, despite disparity in drift distance, both shovelnose and pallid sturgeon usually drifted in the lower 0.5 m of the water column (Braaten et al ., ). It has also been suggested that shovelnose sturgeon can be a model for pallid sturgeon as developmental patterns between these two species are similar during early life history (Colombo et al ., ). Additionally, others have shown that shovelnose sturgeon are adequate surrogates for studies regarding contaminants and contaminant uptake (Ruelle and Keenlyne, ; Schwarz et al ., ; Buckler, ).…”

Discovery and evaluation of candidate sex-determining genes and xenobiotics in the gonads of lake sturgeon (Acipenser fulvescens)

“…These fish were estimated to be 13-14 years old based on the stocking history of the lake, their size relative to growth rates in the lake, and gonad development (Bruch et al 2001;Jackson et al 2002;Colombo et al 2007). From these fish, we collected gonad biopsies with the assistance of veterinarians from Cornell University (P. Bowser, N. Abou-Madi, and their coworkers).…”