Organ differentiation in newly hatched common wolffish

I. B. Falk-Petersen,  T. K. Hansen-2001  

Journal of Fish Biology, 59(6): 1465-1482

Abstract:

Wolffish Anarhichas lupus (Anarhichadidae) hatch from large demersal eggs (c.5-6mm) after a long incubation period (c.800-1000 degree days) at 20-25mm L_Twith a juvenile appearance: a small yolk sac, pigmented but partly transparent skin densely supplied with mucous cells, well developed body musculature and a cartilaginous skeleton. The results of histomorphological studies illustrate the apparent functionality of tissues and organs at hatching. The mucosa of the oral cavity and various parts of the digestive channel are well differentiated and the cellular characteristics are described within each region. A stomach with gastric glands is established before hatching. The pancreas has well developed endo- and exocrine tissue and the hepatocytes are vacuolized. The kidney tissue has numerous tubuli and haematopoietic tissue in the bilobed head region. The spleen, thymus and thyroid glands also appear mature. Cones are dominant in the visual cell layer of the retina.

(Department of Aquatic Resources and Environmental Biology, The Norwegian College of Fishery Science, University of Tromsų, N-9037, Tromsų, Norway, Tel.: +47 776 46000, fax: +47 776 56020, email:ingerf@nfh.uit.no)

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