24 



THE AGKICI'LTUKAL NEWS'. 



May 10, 1902. 



WEST INDIAN FISHERIES. 



Th3 Aruin^ial Propa:jation of Sea eggs. 



])it. Caswell (Jkave, Ph. 1)., Assistant in Zoology 

 in the Johns Hopkin's University, ha.s forwarded to the 

 ])epartinent the following paper: — 



Tlie jiresent depleted condition of the .s3a-egg gronmls 

 of Barbados arc sjt fortji in a rjpart of tli3 .sea-egg industry, 

 publi-shed in ths West Inliaii Bulletin, the Quarterly Journal 

 of the Imperial Department of Agriculture for the West 

 Indies. 



After carefully reading the report and di.scu.ssing the 

 que.-stion of a practical remedy for these conditioiis with 

 iJr. J. E. Duerdon, the writer of the report, 1 have decideil that 

 it may be worth while to call the attention of those inter^'stcd 

 in the artificial rL-.tojkingof the sea-egg grounds of Barbados 

 to sonic re.sults whicli I have recently made in the rearing of 

 sea-urchin larv;e which, both in structure and habits, are 

 very similar to the larvas of the Barbados edible s])ecies of 

 sea-urchin, irqipoulk ea-ulenia. 



The method by which I have been able to rear sea- 

 urchin larvie in groat numbers is based upon princijiles which 

 are jiurcly biological, and since the method has been successful 

 when a))plied in the i.iboratory on a small scale, in which the 

 ditticulties to be overcome are much greater than under condi- 

 tions in which the experiment could be carried out on an 

 extensive scale, I think there is little doubt but that it could 

 easily be nude to yield practical results to sueh an extent as 

 to have a commercial value. 



The simplicity of the method and the small expense with 

 which it could bo put into operation are features which are 

 not unimportant when considering its applicability to the 

 case under consideratioTi. When once instituted tlie work of 

 carrying out the method would resolve itself into a routine 

 which could readily be taken up by any intelligent labourer. 



The students of morphology have made many attempts 

 to rear the larvaj of Echinoderm.s in laboratories, for in 

 making a comprehensive study of the structures of tlie adult 

 sea-urchin, it is necessary to follow eich structure from its 

 first beginning in the larva; to its final condition in the adult. 

 To do thi.s, full serious of larv;e are needed covering all the 

 various stages pas.sed through by the eggs in tlieir growth 

 into the adult form. 



Very few of thesj attc:ni)ts to rear Echinoderms in .sea- 

 sitle laboratories have succeeded in producing even a single 

 animal having the adult form, because the methods which 

 have usually been employed have failed to reproduce the 

 natiu'al conditions under which the larvae feed and develop 

 in the open sea. 



During the summer of 1900 while working in tiic 

 United States Fi.sh tJommission Laboratory at lieaufort, 

 N. C, I accidentally discovered a method which 1 have siiu'e 

 n.sed witli very gratifying success. Late in the summer of 

 1900 1 reared a ' brood' of thou.samls of sea-m-chins /Vom ilie. 

 e'jg to the a'lult form. In 1901 two such 'broods' were 

 carried through and also a ' brood' of a species of Ophiiiriil. 

 In addition to this, the little sea-urchins together with some 

 just metamorphosed sjiatHngoids were taken from the sea- 



shore to the Zoological Laboratory of the Johns Hopkins 

 I'nivcrsity where they lived and grew normally and rajiidly 

 for more than two months in an a<piarium which had but 

 about <me liter of sea water. During this time the water 

 of the aquarium was changed but twice. 



The conditions in this a juarluni, so far as the little 

 Echinoderms were concerned, were ai)pro.\iniat<;ly those of 

 the sea and, as in the sea, the .supply of oxygen and food 

 were self-perpetuating. 



It is very [)robable that the food of the larv:e of the 

 Barbados se;i-urchin consists of the same or similar micro- 

 scopic plants which make uji the f o )d .suiijdy of the larvie of 

 the Be.iufort species. It is alsj probable that these microscojiic 

 ]i!ants can be easily collected and made to live and multijily 

 with the larvai of the sea-urchins. 



If this can be done, then the important questions of food 

 and oxygen for the larv;e which it is desired to rear are 

 .solved, and when such cultures are started, and when the fully 

 tleveloiied larva; can be liberated over the se;i-egg grounds in 

 great numbers, in the stage which immediately precedes that 

 in which they settle to the bottom, then the restocking of 

 the scii-egg grounds will have begun ; for before the tide can 

 have carried the larv;e out to sea many of them will have 

 taken up their life upon the bottom, and in a short time there 

 is every reason to cxi)cct they will grow to a marketable size. 



Baltin.ore, March 7, 1902. 



The Tarpon. 



The following inti^rmation on the habits of the 

 tarjioii, known in British Guiana as the ' KufFuni,' is 

 taken from a paj)er by ' Oxon' on some notes on Fly 

 Fishing in British Guiana (Timehri,Vo\ X. pp. 305-6, 

 December I89G). It forms an interesting addition 

 to the notes contributed by the Hon'ble L. J. Bertram 

 and reproduced on page 8 of this Journal : — • 



The finest fi.sh in the cilony for sporting i)urposes is the 

 cutl'um, a large fish of the herring family. Aly old friend 

 B. J. (!o Ifrey always as.serted that it is the s;ime fish as the 

 ta''|ion which affords such splend! d sjiort in the lagoons of 

 Klorida and I believe he was right. It is a hand.some fi.sh, 

 silvery like a salm )n, with large scales, and the gamest fish I 

 ever hooked. He has been caught in our rivers and creeks 

 up to twenty pounds in weight, and when hooked he 

 makes some determined rushes ; when he finds that he cannot 

 free himse'f, he makes tremendous leijjs into the air, coming 

 down with a si)lash that makes you trendile for your tackle. 

 The cufiTum has a b )ny [iilate and the siile-s (.f his mouth are 

 like parchment, so that it is very difficult to hook him securely; 

 a dozen fish may be touched for one that is landed. He is 

 generally caught with a I'cd and white mackerel or g.iudy 

 .salmon fly ; but the largest fish are caught with live bait, 

 fishing as you would for pike. As I have s;iid, I have nev<^r 

 seen cuttuir, caught with a rod, more than twenty jiounds in 

 weight ; but I once s;iw a fish .") ft. in length which wa.s 

 caught in a net off the mouth of the .MahaicA Creek. 



Pond flies. Amongst the day flying insect.s, few arc 

 more noticeable than the jiond flies or <lragon-flies. .Ml day 

 hawking in the air with wcasional rests on a twig or gra.s-s 

 stalk, these voracious in.sects excrci.se no .small function in 

 Nature's economy. Their food consists of the smaller insi^ct.s 

 of which they are .so many always on the wing, ami the 

 destruction the jiond flics arc responsible for mu.st be truly 

 enormous. Bond flies are the perfect form of the ' water tiger,' 



