which has been used for many years in Great Britain. In it, a 

 strip of silk is pulled over an orifice through which water is passed. 

 This silk is rolled up in a little chamber along with some formal- 

 dehyde to preserve the catch and thus provide a continuous record 

 of the life that is captured at a given depth along the path of the 

 ve s s e 1 . 



In addition to these small nets, there are the large nets such 

 as mid-water trawls which are useful for sampling the larger ani- 

 mals of the open sea. There are many kinds and sizes, built for 

 a variety of purposes. They are in active development; some may 

 be modifications of commercial gear and others special designs. 

 Stationary gill nets take in animals by entangling them and are 

 quite selective. All nets are selective, in fact, which renders 

 interpretation of results difficult. 



The old-fashioned way of catching fish by a baited hook is still 

 a method of capturing biological samples. Japanese longline gear 

 and modifications thereof can be used to obtain quantitative est- 

 imates of the predators in the open sea. This gear is composed of 

 a horizontal buoyed line which in commercial applications may be 

 upwards of 60 miles in length. Baited hooks on droppers are hung 

 from this, usually about 30 fathoms apart. This gear takes sharks, 

 large tunas, marlins, and other sizable carnivorous fishes. 



I have listed a nunnber of means by which biological observa- 

 tions of the ocean may be taken. The sensing instruments are like- 

 ly to prove more compatible with survey requirements in that they 

 may permit continuous observations while underway or simultan- 

 eous observations with physical measurements while on station. 

 Certain of the instruments that depend upon the capture of organ- 

 isms require, in effect, a full scale fishing operation and would 

 be difficult to coordinate adequately with the other aspects of a 

 survey. This means that the equipment for measuring certain 

 biological parameters, or certain trophic levels -- especially 

 those at the peak of the food pyramid -- will not be included 

 within the ordinary survey ship suit of instruments, but nnust be 

 used on special vessels. The means of estimating these biological 

 parameters are not perhaps adequately developed or standardized 

 enough to justify their inclusion in the ocean survey suit of instru- 

 ments at this time; they are better left as missions for research 

 ships. 



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