Contribution from the Laboratory of the Marine Biological Association of San Diego. Diurnal Migrations of Calanus finmarchicus in the San Diego Region during 1909
✍ Scribed by Prof. Calvin O. Esterly
- Publisher
- John Wiley and Sons
- Year
- 1911
- Tongue
- English
- Weight
- 721 KB
- Volume
- 4
- Category
- Article
- ISSN
- 1434-2944
No coin nor oath required. For personal study only.
✦ Synopsis
This species was chosen as a basis for studying the movements and distribution of the Copepoda in the San Diego Region because it occurs more abundantly than any other form. The collections on which this paper is based consist of surface and deep horizontal hauls. The surface collections were made with an ordinary 000 net whose orifice was 97,5 cm in diameter. The deep hauls were made with the Kof oid closing net, also of 000 mesh, with an opening 18,5 cm in diameter. It is plain that the surface net would filter more water than the Kofoid net would under the same conditions, and therefore the former might be expected to take more specimens. In attempting to make up for the difference in size of the two nets, the number of animals taken with the smaller net has been multiplied by 28 because the ratio between the areas of the openings of the nets is as 1:28. This procedure gives numbers that seem to be far too large, yet it need not necessarily lead to confusion. An accurate correlation would depend on many factors (such ais distance and rate of hauling, currents encountered, variations in pressure) which are unknown, and the method of reducing to common terms employed here should be taken only for what it is worth.
The number of animals was counted in all hauls but one where the number was extremely large; a careful estimate was made in that case. The figures in the tables which give numbers of individuals are the averages of several hauls, and have also been reckoned on a basis of a haul one hour in duration. Whenever decimals occurred, 0,5 or less was neglected and more was counted as 1. Animals in the stage 93 2240 n n 3. 11:30P.M.-12:37 A.M. 2 n n 2 ii n 5236 n * 4. 4:26 A.M.-6:03A.M. ,, 5 , , 5 n 420 n n Revne d. ges. Hydrobiol. n. Hydrogr. Bd.IV. H. 1 u. 2. 10 146 C. 0. Esterly. C. At 30-50 fathoms. 1. From 6 : 05 A. hI.-5 : 55 P. M. found in 4 out of 7 hauls with 402 per hour 2. ,, 6:13 P.M.-10 P.M. , , 4 , , , , 5 ,, 1036 , , 3. 4 ~2 6 A.M.-6:03A.M* n n 1 w n 3 n n 56 n w D. At 100 fathoms. 1. From 6 : 05 A. &I.-5 : 55 P. Ill. found in 1 out of 2 hauls with & I per hour 2.