H-42 



RESEARCH PROGRAMMES 



three times that found at Auckland Islands: estimates of possible annual harvest ranged from 

 385 000 to 530 000 crabs (Ryff and Voller, 1976). 



Apart from the stock estimates mentioned above, there is information on experimental 

 fishing and processing, and some brief observations on moulting, reproduction, feeding and 

 behaviour. Generally there is a paucity of information on the biology and population dynamics 

 of this species. 



(d) Other benthic invertebrates of potential commercial interest. 



Other crustacean species, which have little potential value in view of their low population 

 numbers and/or difficulty in catching are: the Antarctic shrimps {Notocrangon antarcticus and 

 Oiorismus antarcticus), other species of lithodid crabs especially Paralomis sp, and the smooth 

 red swimming crab Nectocarcinus bennetti. 



Except for the scdWo^p Adamussium colbecki and tlie clam Laternula elliptica, the Antarctic 

 shelf appears to contain few species of bivalve fauna similar to those exploited elsewhere. The 

 sub-Antarctic islands also lack such bivalves, except for Mytilus ediilis desolationis and 

 Aulacomya ater which are abundant at Kerguelen, and M.e. desolationis and A. maoriana 

 around the New Zealand sub-Antarctic islands. 



Several other benthic invertebrate species are possibly suitable for human consumption. 

 These include the gastropod Neobuccinum eatoni and sea urchins of the genus Sterechinus. 

 They occur in shallow water and are generally circumpolar in distribution. 



In view of the small size of the stocks and the logistic problems involved, it w concluded 

 that the harvesting of these resources is not practical. 



2.8.2 Objectives 



The research programme for benthic invertebrates is to be established within the 

 framework of the following broad objectives: 



1 . Assessment of the state of presently exploited stocks. 



2. Identification of new resources and assessment of their magnitude. 



3. Establishment of monitoring systems for exploited stocks. 



4. Evaluation of biological and environmental factors which will lead to refinement of 

 population models. 



2.8.3 Research programmes 



Assessment of the potential of unexploited stocks requires systematic fishing, for which 

 the following proposals can be made. 



1. Catch and effort. 



The distribution of both rock lobsters and crabs is usually closely related to depth. 

 PreUminary investigation of bathymetry, or acoustic surveys, can facilitate the systematic 

 setting of traps and the delineation of areas of interest. A preliminary gross estmiate of stock 

 size can be made by combining catch rate with survey area and depth information. 



Catch and effort statistics should be collected; these should include data on numbers, 

 nominal weight, and production weight, as well as number of vessels, type of gear, number of 

 traps per vessel, and number of trap days, hours or hauls. The nature of the catch and/or 

 production should be recorded by data on size composition, state of exoskeleton, sex ratio, 

 state of reproductive organs, and size at maturity. It is recommended that rock lobster size be 

 expressed as carapace length, measured from the tip of the rostrum to the mid-dorsal end of the 

 carapace, and that the size of lithodid crabs be measured from the posterior orbit to the 

 mid-dorsal end of the carapace. 



