The characteristics of Japanese krill fishery were reviewed in several examples based on the information recorded on log book. While searching behaviour seems to be the basis of this fishery, CPUE in terms of catch per minute of towing was thought to be an useful index of patch density and possibly of local abundance.
Abstract:
A crude mathematical framework is developed to describe krill abundance in terms of selected parameters of various aggregation behaviours exhibited by krill (Euphausia superba Dana). The relationship of combinations of these parameters to various possible measures of catch-per-unit-effort (CPUE) for the Antarctic krill fishery is considered. The combined index of catch-per-hour of trawling divided by average inter-concentration search time is suggested as a possible measure of krill abundance; such an index should be stratified both spatially and by krill aggregation type - this has implications for routine data collection. Models should be constructed to investigate how substantial non-linearities in the relationship between the index and krill abundance might be.
There is no abstract available for this document.
There is no abstract available for this document.
There is no abstract available for this document.
There is no abstract available for this document.
There is no abstract available for this document.
Abstract:
In order to extend the knowledge on the age and growth of antarctic fishes, the authors present herein the results of the data processing arising from samplings o f a species belonging to the Chaenichthyidae family, Champsocephalus gunnari.
The age determination of this species, was made using the otolith fine cutting technique. Through the reading of the growth rings the age classes corresponding to3, 4, 5 and 6 year old males and 3, 4 and 5 year old females were found. The growth curves were adjusted according to the classic model and were estimated as:
♂ Lt= 497.5 [1-e-0.39 (t-1.44)]
♀ Lt = 627.1 [1-e-0.19 (t+0.03)]