Shell lesions in New Zealand Haliotis spp. (Mollusca, Gastropoda)

Shell lesions are reported in the three New Zealand species of Haliotis (Ha liotis iris Martyn, 1784, Haliotis australis Gmelin, 1791, and Haliotis vir ginea virginea Gmelin, 1791). The lesions are described as blisters of conc hiolin, and occasionally nacreous material, forming on the inside of the ab alone shell near the apex. Twelve (16%) of 76 H. iris, 21 (38%) of 56 H. au stralia, and 5 (100%) of 5 H. virginea virginea, had lesions, some of which disrupted the adductor muscle scar. Specific histological stains confirmed the presence of fungal hyphae within lesions and the shell matrix of affec ted H. iris and H, australis. No pathological changes or evidence of fungal infection were observed in any of the soft tissues of the lesion-bearing a nimals examined. Lesions were most prevalent in populations in the Catlins region of South Otago and off the northeast coast of Stewart Island, althou gh they were found throughout the southern New Zealand range of H. iris, in cluding offshore islands. The mean shell length of lesion-bearing H. iris w as significantly (p < 0.05) less than that of nonlesion-bearing H, iris at 4 of 11 locations sampled.