not in southeastern Bering Sea as defined 

 in figure 1 (page iv), the U. S. Coast Guard 

 (1936) has shown a current flowing toward 

 the northwest near Nunivak Island. The sub- 

 sequent recovery in southeastern Bering Sea 

 of drift bottles released south of Unimak 

 Island (Thompson and Van Cleve, 1936) also 

 lends support to the counterclockwise circu- 

 lation. 



The forces fundamental to the above 

 circulation have not been determined because 

 of the lack of sufficient data. The possi- 

 ble forces which may support or contribute 

 to the support of this circulation are (1) 

 the addition of fresh water from streams of 

 the surrounding land, (2) the buildup by 

 winds of a hydraulic head of water cilong the 

 coasts which upon releixation would set up 

 temporary currents, and (3) the addition of 

 water to the region from the North Pacific 

 through Unimak Pass as indicated by the 

 before-mentioned drift bottle releases and 

 subsequent recoveries. 



EFFECTS OF CURRENTS ON THE 

 KING CRAB LARVAE 



One of the major effects of the currents 

 would be upon the larvae during the zoea 

 stages of the king crab, when the larvae are 

 planktonic. If we assume that the findings 

 of Marukawa (1933) are valid concerning king 

 crab in the natural environment, the organ- 

 isms spend approximately 60 days as zoea 

 larvae, of which 5 days are spent in the 

 upper water layers before the larvae migrate 

 to the water layers immediately above the 

 bottom where the remainder of the time as 

 zoea larvae is spent. The glaucothoeal lar- 

 vae, formed from the zoea larvae, exist 

 approximately 20 days, this period being 

 spent resting on the bottom or swimming in 

 the water immediately above the bottom. 



The effect of the currents on the 

 larvae is greatest in the dispersion or con- 

 centration of the larvae, depending upon 

 the type of current flow in their immediate 

 environment. Should hatching occur in a 

 region of linear currents, the zoea would 

 be carried and dispersed by the forth and 

 back movement of the tidal currents, with a 

 net movement of the larvae in the direction 

 of the steady currents. In addition, the 

 larvae would tend to be concentrated where 

 gyrals and eddies are formed. 



Because the adult female moults very 

 shortly after the eggs which she has been 

 carrying hatch, we can consider the areas 

 of moulting adult females as the areas of 

 larval hatching. In 1957, just prior to the 

 current station observations, both moulting 

 females and females with eggs approaching 

 the hatch were observed along the Alaskan 

 Peninsula between Amak Island and Port Mol- 

 ler (figure 1), with the largest abundance 

 near Amak Island. Because of the limited 

 scope of the investigations of crab distri- 

 bution prior to the current stations, no 

 other areas of moulting females or females 

 with eggs ready to hatch were located. 



If we consider the relation between 

 the average velocity of the average current 

 along the Peninsula, 0.04 knot, and the 60- 

 day period the king crab spends as a zoea 

 larvae, we may estimate that the current 

 would carry the larvae approximately 60 

 miles; variations that might occur would be 

 caused by the tidal currents. In effect, 

 the zoea larvae hatched in the vicinity of 

 Amak Island would be carried into the vicin- 

 ity of Port Moller. As a matter of observa- 

 tion, the only area where small crabs were 

 located on the above-mentioned cruise is in 

 the vicinity of Black Hills, approximately 

 50 miles from Amak Island. Should hatching 

 occur in other regions, which is very prob- 

 able, the zoea larvae would be carried, 

 generally, in the direction of the average 

 current for a distance obviously depending 

 upon the net current velocity and the time 

 spent as planktonic larvae. 



I 



Because of the habitat of the glauco- 

 thoeal larvae, the movements of the- larvae 

 caused by the currents are practically 

 indeterminable. About the only time the J 

 larvae of this stage would be affected by " 

 the currents would be during their periods 

 of swimming, and then perhaps for only short 

 periods of time. 



Not only do the currents affect the 

 distribution of the larvae within an area, 

 but they may carry into an area larvae from 

 king crab populations of other areas. Be- 

 cause of the suspected flow of water from 

 the North Pacific into southeastern Bering 

 Sea, by way cf Unimak Pass, recruitment of 

 larvae into the Bering Sea from king crab 

 populations south of the Alaskan Peninsula 

 is a possibility. False Pass (figure 1), 

 a small pass between Unimak Island and the 



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