Aspects of body size and gonadal histology in the Antarctic toothfish, Dissostichus mawsoni, from McMurdo Sound, Antarctica |
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| Authors: | Joseph T. Eastman Arthur L. DeVries |
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| Affiliation: | (1) Department of Biomedical Sciences, College of Osteopathic Medicine, Ohio University, Athens, OH 45701-2979, USA e-mail: eastman@ohiou.edu Tel.: +1-740-5932350, Fax: +1-740-5972778, US;(2) Department of Ecology, Ethology and Evolution, University of Illinois, Urbana, IL 61801-3704, USA, US |
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| Abstract: | Twenty-eight specimens of the large notothenioid Dissostichus mawsoni were dissected after capture on a set line near the southern limit of its range in McMurdo Sound, Antarctica. Total length (L T) averaged 127.3 cm (range 90–162 cm) and weight (W ) was 26.7 kg (range 10.4–60.3 kg). The length-weight relationship was W=3.44×10−5 L T 2.85 (n=28, r 2=0.96). Subcutaneous lipid thickness averaged 2.6 mm and showed no difference due to sex, but a significant weak relationship to W and L T. Hepatosomatic index (I H) was 1.6% for females and 1.7% for males; gonadosomatic index (I G) was 0.9% for females and 0.2% for males. Although specimens were large and sexually mature, the histology indicated that the gonads of this November sample were in a resting stage. Testes lacked spermatids and spermatozoa. Oocytes were in the previtellogenic stage (91.2%) or in the first stage of vitellogenesis (8.8%). A few atretic oocytes and empty follicles indicated that some females in this sample had spawned previously. A summary of the life-cycle is also presented. Accepted: 27 September 1999 |
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