154 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



tions proved true, and to forget the many times when they were not ful- 

 filled. Such persons will never think of comparing the cases when such 

 signs were without any significance whatever with those cases when they 

 were followed by certain results, nor do they weigh the probability of the 

 one or the other. They are always inclined to follow a post hoc by an 

 ergo propicr hoc. The opinions of fishermen are also often at variance 

 with each other, even with regard to the influence of outward circum- 

 stances on the fisheries. It must finally not be forgotten that the nature 

 of the fisheries themselves requires great caution in applying results 

 gained by positive experience. Fishing is generally carried on with very 

 insufficient apparatus and only at that time and in those places where the 

 greatest gain may be expected. There is a great difference between the 

 occurrence of fish in a certain place and the occurrence of fisheries in 

 the same. The fish may, for instance, come in a certain way which 

 makes it impossible to catch them with the only apparatus on hand, and 

 the fisheries, therefore, come to an abrupt end, although there are plenty 

 of fish. The fishermen are, moreover, frequently governed by prejudices 

 and actually cease to fish before the most profitable period of the fish- 

 ing-season has arrived, simply because they think they have noticed 

 some adverse signs. All the information gathered from fishermen must, 

 therefore, be sifted in the most critical manner, and the most extensive 

 fishing must be carried on by the observer himself with every imaginable 

 kind of api^aratus. in order to corroborate or disprove the statements of 

 the fishermen. 



§ 20. In order to gain more reliable and more complete knowledge than 

 can be obtained from fishermen or through historical researches, it is, as 

 I remarked above, absolutely necessary to make direct personal obser- 

 vations in a number of places. There should be a separate observer in 

 every place, who, following a well-devised plan, would make daily ob- 

 servations on the fisheries, &c., which would serve as a basis for a natu- 

 ral history of fishes, and for historical and statistical fishery-reports 

 {annals of fisheries). The superintendents of the fisheries would cer- 

 tainly be able to render much valuable assistance in making these obser- 

 vations. 



§ 21. The necessity of comparing the course of the fish, their mode of 

 life, and their migrations, with the meteorological and hydrological con- 

 ditions, for the purpose of increasing our knowledge of their natural 

 history, has long since been recognized, and caused the Royal Scientific 

 Society at Gottenburg, as early as the beginning of this century, whilst 

 the last great herring-fisheries were stiU going on, to set a prize for the 

 best treatise on "The influence of the currents on the Bohusliin herring- 

 fisheries." When the fisheries ceased, Dr. P. Dubb, the most unprejudiced 

 and learned of our older authors who have given attention to the Bohus- 

 lan herring-fisheries, also expressed the opinion that meteorological and 

 hydrological causes occasioned the periodical coming and going of the 



