The Antarctic dragonfish Parachaenichthys charcoti is commonly found in shelf waters of islands in the southern Scotia Arc. Its northern congener P. georgianus is distributed on the shelves of South Georgia and the South Sandwich Islands. Biological information on P. charcoti is limited and restricted largely to reproductive traits and feeding habits. The present study fills this gap, providing the first data on age and growth of this species by otolith reading. Age was estimated in juveniles and adults by counting annuli on otoliths. Age of early juveniles was determined by microincrement counts (considered to be daily rings). Age estimates of juveniles and adults ranged from 1 to 9 years, with a high percentage agreement between readings and low values of counting variability indices APE (3.3 %) and CV (4.7 %). Age of early juve¬niles ranged from 160 to 204 days, all showing an evident check at 32-35 days of age, tentatively linked to the first larval exogenous feeding. The estimated values of von Bertalanffy growth parameters L,, and k were 53.55 cm and 0.22, respectively, and the index of growth performance P was 2.33. Hatching in P. charcoti takes place in late winter, from August to September. Compared to other nototheni¬oids inhabiting the Seasonal Pack-ice Zone, P. charcoti is a relatively fast growing species with moderate longevity, sharing several biological characteristics with its sister species P. georgianus.
Age and growth of the Antarctic dragonfish Parachaenichthys charcoti (Pisces, Bathydraconidae) from the southern Scotia Arc
La Mesa;
2012
Abstract
The Antarctic dragonfish Parachaenichthys charcoti is commonly found in shelf waters of islands in the southern Scotia Arc. Its northern congener P. georgianus is distributed on the shelves of South Georgia and the South Sandwich Islands. Biological information on P. charcoti is limited and restricted largely to reproductive traits and feeding habits. The present study fills this gap, providing the first data on age and growth of this species by otolith reading. Age was estimated in juveniles and adults by counting annuli on otoliths. Age of early juveniles was determined by microincrement counts (considered to be daily rings). Age estimates of juveniles and adults ranged from 1 to 9 years, with a high percentage agreement between readings and low values of counting variability indices APE (3.3 %) and CV (4.7 %). Age of early juve¬niles ranged from 160 to 204 days, all showing an evident check at 32-35 days of age, tentatively linked to the first larval exogenous feeding. The estimated values of von Bertalanffy growth parameters L,, and k were 53.55 cm and 0.22, respectively, and the index of growth performance P was 2.33. Hatching in P. charcoti takes place in late winter, from August to September. Compared to other nototheni¬oids inhabiting the Seasonal Pack-ice Zone, P. charcoti is a relatively fast growing species with moderate longevity, sharing several biological characteristics with its sister species P. georgianus.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
