In vivo exposure of clearnose skates, Raja eglanteria, to ionising X-radiation: Acute effects on the peripheral blood, spleen, and epigonal and Leydig organs

The effects of ionising radiation on the peripheral blood, spleen, and epigonal and Leydig organs of cartilaginous fishes were investigated using juvenile clearnose skates, Raja eglanteria. Skates (N = 80) were sacrificed 12 days after exposure to 0–75 Gy of X-radiation, and morphometrics (body mass, disc width, total length), mass of spleens and epigonal organs, and peripheral blood leucocyte (PBL) counts were compared to controls using ANOVA. Spleen and epigonal organ mass and PBL counts declined logarithmically as a function of radiation dose. To assess recovery from X-radiation, skates (N = 40) were exposed to 0, 9 or 18 Gy and sacrificed when moribund or on days 10, 20, 30 and 40 post-irradiation. Partial recovery of Leydig organ and splenic red pulp was evident after 40 days in skates exposed to 9 Gy, but no indication of recovery was apparent at higher doses. Median lethal dose by 30 days (LD50/30) was calculated to be 9–18 Gy, similar to that determined for other fishes.