Polyfluorochrome marking slows growth only during the marking month in the green sea urchin Strongylocentrotus droebachiensis

Abstract

Used singly, the fluorochrome tags tetracycline and calcein have yielded important insights into sea urchin biology, especially regarding growth. We present a new method of tagging using sequential fluorochrome markers, as well as a more precise method of quantifying growth. Such polyfluorochromes enable repeated markings that allow measurement of multiple growth points and unique identification of individuals or groups. We marked sea urchins, Strongylocentrotus droebachiensis, with four fluorochromes: alizarin complexone, calcein, calcein blue, and tetracycline. All fluorochromes marked both by injection and immersion. We examined the clarity of the mark produced with low, metabolically scaled doses, and higher doses similar to those that have been previously used. We tested the effect of fluorochromes on survival, growth, jaw size, and gonad size by marking a size range (3.9-44.3 mm in diameter) of urchins with either one or all four fluorochromes. We quantified growth using a nominal diameter, that is a fitted constant, times the cube root of weight, which increased the precision of measurements by a factor of six relative to measured diameter. Growth rate was a decreasing function of diameter except for a growth lag in the smallest urchins. Growth rate data for all sizes were fitted using: gamma distributions; Tanaka functions; and, for larger sizes, straight lines (von Bertalanffy model). All treatments produced clear marks, with higher doses producing more reliably clear marks. Tetracycline marking did not affect growth; other treatments produced only transient slowing of growth in the marking month. Growth rate, survival, gonad production, and jaw weight did not differ between control and treatments during the following 6 months. Thus, polyfluorochromes produce reliable marks that do not significantly affect growth or gonad production.

Echinometra sea urchins acclimatized to elevated pCO2 at volcanic vents outperform those under present‐day pCO2 conditions

“…In total, 138 individuals were tagged at the vent site and 141 individuals at the Upa‐Upasina control site. While the incorporation of the fluorescent tag sometimes occurs in a subset of sampled individuals, previous laboratory studies have found no evidence that tetracycline‐tagged and nontagged animals have different growth rates (Russell & Urbaniak, ; Ellers & Johnson, ). Therefore, growth rates measured in the present study are assumed to represent growth within the populations, with no bias toward either faster or slower growth in tagged animals.…”

Ultrascale and microscale growth dynamics of the cidaroid spine of Phyllacanthus imperialis revealed by 26Mg labeling and NanoSIMS isotopic imaging

“…In addition to these rather straightforward observations, over the last decades there have been major advances in our understanding of growth dynamics in echinoderms, through application of more direct labeling methods with fluorescent markers (e.g., Kobayashi and Taki, ; Märkel, ; Pearse and Pearse, ; Ebert, ; Russell, ; Kenner, ; Russell et al, ; Ellers and Johnson, ; Johnson et al, and literature cited therein). These markers (including alizarin complexone, calcein, calcein blue, and tetracycline) bind to Ca 2+ and are incorporated into the growing carbonate skeletons, and can be subsequently observed under ultraviolet illumination (for review see Ebert, ).…”

Efficiency of calcein tagging on juveniles of the sea urchins Diadema africanum and Paracentrotus lividus

“…For example, in experiments with 24‐h calcein baths, concentrations of 125 mg · l −1 (Russell et al . ) and 75 mg · l −1 (Ellers & Johnson ; Johnson et al . ) were used to tag Strongylocentrotus droebachiensis .…”

“…), as well as chemical markers such as fluorochrome staining (Ebert , ,b; Schroeter ; Russell ; Rowley ; Ebert & Russell ). In the latter case, various studies focused on calcein and tetracycline markers have demonstrated that these fluorochromes have a minimal effect on long‐term growth in echinoids (Ebert ; Russell & Urbaniak ; Ellers & Johnson ; Sonnenholzner et al . ) and do not affect their survival or mortality (Lamare & Mladenov ; Russell & Urbaniak ).…”