EFFECTS OF WEATHER OX MARINE ORGANISMS 31 



Usually towards the end of February or eariy in March the water becomes 

 thoroughly stocked with laiwa? of all kinds, crustacean, molluscan, ascidian, etc., and 

 these help much to replenish the larder for many of the larger as well as the smaller 

 fish. The numbers were not laeki-ng this year but they were much later appearing at 

 the surface. Many annelids and crustaceans come to the siurface to spawn and in 

 some cases at least the spawning was delayed. One especially notable case might be 

 mentioned. At a certain time in the spring, certain crustacea-ns, known as schizopods, 

 come to the surface in such countless numbers that large areas of the surface water 

 may be pink from their presence. The two-year-old coho, in the strait of Georgia com- 

 monly called the " blueback," have a decided preference for these and naturally they 

 follow them to the surface and often in their haste go beyond them iiito the air. At 

 this time they may be hooked in large numbers. The schizopod rise was much later 

 than usual this year and in consequence the "blueback" run was also later in the 

 season. 



These are special instances but it is not at all likely that thej' are isolated cases. 

 Many other species large and small would naturally be similarly affected. 



Apparently there has been no special difference in the salinity of the water in 

 the two seasons. The snow melted but slowly at the head waters of the large rivers 

 and in consequence these rivers were lower than usual in the early summer, but on 

 the other hand on account of the greater amount of snow on the lower levels the small 

 streams have kept up their flow better than they did last year at least. 



In the littoral zone, the greatest harm in any o-ae night was probably produced on 

 January 3-4, as on that night, according to the tide tables, the tide went to -0-3 foot 

 at 22-0'7 and the minimum temperature oi the air during the night was -9-0°0 

 (15-8°F). With such a long run out, even half-tide shore forms, would be exposed 

 to the cold for a long period. It is quite possible, however, that the cumulative effect 

 of the <>ontinued cold from January 15 to Ja-nuary 19, with quite low tides, would be 

 even greater than the effect during that one night. For these four nights we had the 

 following: 



January 15-16 — Low tide, 2-6 ft. at 20-50; minimum temperature, — 11-3°C, 11-6°F. 



16-17 " 2-2 " 21-30; " - 8-9 15-9 



17-18 " 1-8 " 22-06; " - 7-2 19-0 



18-19 " 1-7 " 22-40; " - 6-9 19-6 



These records are for Sand Heads, at the mouth of the Fraser river. The time 

 is niearlj' the same at Departure bay but the change of tides is about one and» a third 

 times that at Sand Heads. That does not affect the question materially as there 

 would be the same relative change. 



The forms that inhabit the littoral zone may be divided into three classes. First 

 there are those, that move freely, such as certain flat fishes, that go in and out with 

 the tide. These would not suffer with the cold at low tide. Secondly, there are those 

 that move less freely and are thus left on the shore when the tide goes out but the,y 

 are able to huddle together to retain moisture as the starfish do or keep under cover 

 of seaweed or rocks as many of the crustaceans' do. These might suffer but not ver.y 

 seriously, siiDce that which would protect them from being dried out would also pro- 

 tect them from the cold. Thirdl.v there are the sessile forms, that throughout a great 

 portion of their life-history remain firmly attached to rocks, logs, etc. They are left 

 behind when the tide recedes and have no means of getting shelter or of retaining" 

 any very large amount of moisture. It is to this class that the oyster belongs and 

 such as these are the worst sufferers. Reference has already been made to the oyster 

 loeS' a loss which was felt commercially. The destruction ini some cases was more 

 wid-espread than in the case of the oyster, but tJie loss in money value was not so 

 noticeable. 



On sandstone everywhere and sometimes on other rock as well, from nearly- high 

 tide mark to low tide mark, barnacles have established themselves. Those high up 

 on shore are used to extremes as some -of them get moisture and food only at the 



