50 COI^ERCIAL FISHERIES REVIEW Vol. 13, No. 7 



Union of South Africa 



PILCHARD KE3EARCE PROGRAM FINDINGS REPOR'TED ; South Africa's fish meal and oil 

 industry has limited its expansion pending a determination of pilchard and "maas- 

 banker" (menhaden) resources off the west coast of South Africa, the American Con- 

 sul reported in a May 10 dispatch from Cape Town. Ihe objective of this research 

 program was to ascertain to what extent pilchard populations can replace the mor- 

 tality inflicted by decimation, either human or predatory, by natural reproduction, 

 and the potential productivity of the pilchard populations. The scope is to de- 

 termine the wisest exploitation of the available resources. 



Areas Investigated ; Hie inshore work at sea was carried out by two vessels, 

 R. v. Schipa and P. B. Palinurus, from April I95O to March I95I within a sea area 

 of approximately 800 square miles, incorporating the whole of St, Helena Bay and 

 bounded by latitudes 32° S. and 34°47' S. , the shoreline, and longitude 17°50' E. 

 At the 15 stations worked weekly, oceanographical and biological (mainly plankto- 

 logical) data were collected and recorded. Catches from commercial fishing vessels 

 were sampled at sea and on shore. 



Offshore work at sea was handled by the R. S. Africans II , operating from Cape 

 Town as a base. It completed 21 cruises and bimonthly covered 20 routine stations 

 located within a sea area of approximately 4»800 square miles bounded by the lati- 

 tudes of Lamberts Bay and Saldanha Bay, the shoreline, and the 200-fathom contour. 

 Operations at these stations were similar to those for the inshore stations. This 

 vessel also operated in a non-routine exploratory field outside of the Cape Point 

 latitude in the south, the Hondeklip Bay latitude in the north, and as far as I70 

 miles offshore. This was done in an attempt to locate mass-spawning or breeding 

 areas of the pilchards. A continuous echo-sounding search with appropriate graphic 

 recordings for subsurface fish schools was maintained by the R. S, Africana II . 



Field stations at Lamberts and Stumpnose Bays collected and examined samples 

 taken from catches of individual commercial craft. An examination of plankton 

 hauls made by the inshore research vessels was also undertaken at these stations. 



Findings : Preliminary findings contained in this report suggest that a more 

 intensive exploration of pilchard resources could be practiced without depleting 

 resources. However, the Division of Fisheries is reluctant to permit an easing of 

 restrictions until completion of its research program. Some findings of the pro- 

 gram are as follows: 



1. HYDROLOGY: AVERAGE TEMPERATURES WERE HIGHER INSHORE IN WINTER THAN 

 IN EARLY SUMMER, A FACT CONNECTED WITH THE PREVALENCE OF SOUTHERLY 

 WINDS IN SUMMER WHICH INDUCED UPWELLING OF COLDER WATER NEAR THE 

 COAST. SOME 50-80 MILES OFF SHORE, THE AMOUNT OF UPWELLING IN 

 EARLY SUMMER WAS NOT SUFFICIENT TO COUNTERACT THE RISE IN TEMPER- 

 ATURE DUE TO SOLAR RADIATION AND CONSEQUENTLY EARLY SUMMER TEMPER- 

 ATURES OFF SHORE WERE HIGHER THAN IN WINTER. OPPOSITELY-DIRECTED 

 CURRENTS WERE NOT ALWAYS PRESENT AND WERE SOMETIMES FOUND AT DIF- 

 FERENT DISTANCES FROM THE COAST. THE CHIEF FACTOR CONTROLLING THE 

 PRESENCE OF THESE CURRENTS IS CONSIDERED TO BE THE DIRECTION OF 

 THE SURFACE WIND. LARGE SWIRLS OR EDDIES OF WATER APPEARED TO BE 

 PRESENT, SOME MOVING CLOCKWISE, OTHERS COUNTERCLOCKWISE. THE 

 AREAS BETWEEN OPPOS I TfLY-D I RECTED CURRENTS ARE OF FUNDAMENTAL IM- 

 PORTANCE TO THE SUPPLY OF NUTRIENT SALTS (e.G., PHOSPHATES) TO 

 PLANKTON ON WHICH PILCHARDS FEED. THE MOVEMENT INSHORE OR AWAY 

 FROM THE SHORE OF SUCH AREAS HAS A BASIC INFLUENCE ON THE AVAIL- 

 ABILITY OF THE PILCHARD FOODSTUFFS NEAR THE REGIONS OF INTENSIVE 

 FISHING IN ST. HELENA BAY. 



