EFFECT OF WATER TEMPERATURE ON 

 LAKE TROUT EGGS DURING INCUBATION 



A series of practical experimental studies were undertaken at Wiarton and 

 Tarentorus hatcheries to investigate and compare the rate of survival of lake 

 trout during the period of egg incubation and the early stage of development of 

 the fry. The eggs were collected from wild lake trout taken from Lake Manitou 

 and Lake Simcoe. They were then transferred directly to each station where 

 they were incubated and hatched in regular hatchery troughs. Results from these 

 studies showed a marked difference in survival rate of the egg stocks reared at 

 the two hatcheries. Considerably higher losses were encountered in both lots of 

 eggs reared in the warmer spring water supply at Tarentorus hatchery confirming 

 earlier observations that the higher temperature of spring water supplies may 

 adversely affect the survival of lake trout spawn. Further detailed study is planned 

 to determine the optimum temperature for the incubation of lake trout eggs. 



Private Hatcheries 



This year legislation was established under The Ontario Game and Fish Act 

 providing for the sale of smallmouth bass, largemouth bass, brook trout, brown 

 trout, rainbow trout, Kamloops trout and Aurora trout for restocking purposes 

 and for the sale of brook trout, brown trout and rainbow trout for human 

 consumption under the authority of separate licences issued by the Department. 

 Previously, the sale of bass and trout was restricted to restocking only and these 

 operations were administered under a permit system. 



The new licences are available to any private landowner with a suitable 

 water supply on his property for a fee of $10.00 each. The licence to sell fish for 

 human consumption is provided only to those landowners with a water supply 

 which is wholly contained on their own property and is not located on a natural 

 watercourse, except where such watercourse originates on the property. All fish 

 must also be tagged or packaged before being sold. The requirements for a licence 

 to sell fish for restocking purposes are less stringent, but authorization for all 

 plantings must be obtained from the Department before the fish may be trans- 

 ported from the hatchery property. 



Nineteen licences authorizing the sale of fish for human consumption were 

 issued during the current year, but none of the licencees reported selling any 

 significant number of fish for this purpose. Twenty-five licences were issued for 

 the sale of fish for restocking purposes. This is an increase of six over the number 

 of permits issued for this purpose in 1962. A summary of the distribution of fish 

 for restocking from private hatcheries is outlined in Table IV. 



SPECIAL PROJECTS 



1. NET SECTION 



The staff of the Net Section at Maple participated in various netting 

 operations undertaken directly or in co-operation with district personnel. Fish 

 tagging projects were conducted on the Talbot River (Lake Simcoe District), 

 Shawanaga Basin of Georgian Bay (Parry Sound District), Mistinikon Lake 

 (Swastika District), North Channel at Blind River (Sault Ste. Marie District), 

 Batchawana Bay of Lake Superior (Sault Ste. Marie District), and on Lake 

 Simcoe (Lake Simcoe District). Surveys of fish populations were carried out 

 on the Raisin River and Lake St. Francis (Kemptville District), Plevna Lake 



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