226 Transactioits. 



bello Peninsula, and of the strong flow passing round the peninsula into 

 Big Bay or Lower Portobello Bay (as it is variously called), together with 

 the accessibility of the spot and the possibility of acquiring a small and 

 suitable area of land on easy terms, that the Otago Institute was induced 

 some years ago to select the site for the present fish -hatchery and biological 

 station. In some respects there are drawbacks to the position, but these 

 are more than counterbalanced by the advantages referred to. 



Outside the harbour the ocean-bottom slopes with an easy grade into 

 deep water. Round the rocky portions of the peninsula the grade is steeper. 

 Thus the 30-fathom line comes nearly within two miles of Cape Saunders, 

 a slope of about 1 in 58 ; while off Taiaroa Head it is between six and 

 seven miles distant, a slope of about 1 in 180. The 50-fathom line comes 

 within about eight miles of the coast opposite the mouth of Papanui Inlet, 

 and there would appear to be at that point a depression or slight valley on 

 the ocean-floor running out seawards. The contour-lines on the map accom- 

 panying this paper* (kindly prepared by the Survey Department, Dunedin) 

 can only be taken as approximately accurate, as no detailed survey of the 

 sea-bottom has been made. According to the fishermen who work outside, 

 and who go in for line fishing, there is quite a deep trough or valley about 

 ten miles south-east of Cape Saunders, where the depth very quickly passes 

 from 80 or 90 to 150 fathoms, and from there slopes out to very deep water. 

 A similar sharp depression occurs between thirty and forty miles farther 

 north. Though the exact location of these submarine valleys is not laid 

 down on any map, they are well known to the fishermen, who in suitable 

 conditions of wind and tide find these deeps very excellent fishing-grounds. 



According to the Admiralty charts of this coast still in use, based on 

 the surveys made by Captain J. L. Stokes in the " Acheron " (1849-51), a 

 current sets up the coast in a north-easterly direction at the rate of from 

 one to one and a quarter knots per hour. The " New Zealand Pilot " (8th 

 edition) says, " On the east coast of the South Island the current usually 

 sets northward with a rate of about one mile an hour." According to the 

 fishermen, this current, especially at a distance of five to ten miles off the 

 coast at Cape Saunders, frequently runs at the rate of four miles an hour. 

 It is especially strong just before a south-west wind sets in, and when 

 fishing under such conditions in from 90 to 150 fathoms it is sometimes 

 almost impossible to let the lines down, even with heavy sinkers. On the 

 other hand, just before north-east weather sets in, the current ceases en- 

 tirely, and the lines go down nearly plumb from the boats. One effect 

 of this nearly constant northerly current is the formation of an eddy into 

 Blueskin Bay and round to the north of Taiaroa Head. This frequently 

 causes the accumulation of large quantities of plankton and various pelagic 

 organisms in that sheltered area, and, as a consequence, also the frequent 

 accumulation of large quantities of fish. The general set up the coast of 

 a north-easterly current is one argument in favour of the establishment of 

 a marine hatchery in this part of Otago. Any swimming organisms libe- 

 rated outside of Taiaroa Head, or even within the harbour on an ebl) tide, 

 tend to be carried along the coast northwards. 



One physical phenomenon, which has been observed only since the 

 station was started, is of considerable interest and importance. From the 

 very first daily observations have been made of certain meteorological 



* Map showing the coast-line between Taieri Mouth and Moeraki, with contour- 

 lines showing the depth of the adjacent sea. 



