Aspects of body size and gonadal histology in the Antarctic toothfish, Dissostichus mawsoni, from McMurdo Sound, Antarctica

• Published in: Polar biology 2000-02, Vol.23 (3), p.189-195
• Main Authors: EASTMAN, J. T, DEVRIES, A. L
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Aquaculture; Autoecology; Biological and medical sciences; Body size; Dissostichus mawsoni; Fish; Fundamental and applied biological sciences. Psychology; Gonads; Histology; Marine biology; Morphology; Vertebrata
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s003000050026

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^sub T^) averaged 127.3cm (range 90-162cm) and weight (W) was 26.7kg (range 10.4-60.3kg). The length-weight relationship was W=3.44×10^sup -5^ L^sub T^^sup 2.85^ (n=28, r^sup 2^=0.96). Subcutaneous lipid thickness averaged 2.6mm and showed no difference due to sex, but a significant weak relationship to W and L^sub T^. Hepatosomatic index (I^sub H^) was 1.6% for females and 1.7% for males; gonadosomatic index (I^sub 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.[PUBLICATION ABSTRACT]