Impairment of sea urchin sperm quality by UV-B radiation: predicting fertilization success from sperm motility.
Sperm quality of the sea urchin, Anthocidaris crassispina, after exposure to environmentally realistic UV-B irradiances, was assessed by changes in sperm motility (measured by the computer-assisted sperm analysis (CASA) system), and related to subsequent fertilization success. Percentage motile sperm of A. crassispina declined significantly after exposure to a UV-B dose of 16.2 kJ m(-2), while sperm motion velocity as measured by curvilinear velocity (VCL), straight line velocity (VSL), and average path velocity (VAP) showed significant reduction after exposure to a UV-B dose of 5.4 kJ m(-2). A parallel study showed that fertilization success was significantly reduced after sperm were exposed to UV-B doses > or = 5.4 kJ m(-2). Notably, the four sperm motility parameters were strongly correlated with fertilization success (P < 0.001), followed the increasing order: VSL (r = 0.8) < % motile sperm (r = 0.804) < VCL (r = 0.912) < VAP (r = 0.928). Fertilization success is best predicted by VAP using the exponential model: y = 8.678 + 90.202/[1 + exp(82.83 - x)/10.27)] (r(2) = 0.95). Thus, impairment of sperm motility of sea urchin, as measured by the CASA method, can be used to predict reproductive success and ecological effects.
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DW
Center for Coastal Pollution and Conservation, City University of Hong Kong, Kowloon. bhdwtau@cityu.edu.hk
Chiang
M W L
MW
Tang
J Y M
JY
Yuen
B B H
BB
Wang
Y L
YL
Wu
R S S
RS
D000818:Animals; D004781:Environmental Exposure; D005306:Fertilization / Q000528:radiation effects*; D008297:Male; D011157:Population Dynamics; D012617:Sea Urchins / Q000502:physiology*; D013081:Sperm Motility / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*