Discovery reports (1964) Discovery reports discoveryreports32inst Year: 1964 114 DISCOVERY REPORTS based on the assumption that the organisms whose diurnal movements one is attempting to portray are evenly (or randomly) distributed throughout each depth interval traversed by the vertical nets. But are the larvae of 壉 . superba in fact so disposed? It will be shown later (pp. 234-6) that there are considerable grounds for supposing they are not, but, like the older stages (p. 149), are disposed in shallow ' rafts', no more than a yard or two thick, through which the nets in each instance pa
Discovery reports (1964) Discovery reports discoveryreports32inst Year: 1964 114 DISCOVERY REPORTS based on the assumption that the organisms whose diurnal movements one is attempting to portray are evenly (or randomly) distributed throughout each depth interval traversed by the vertical nets. But are the larvae of 壉 . superba in fact so disposed? It will be shown later (pp. 234-6) that there are considerable grounds for supposing they are not, but, like the older stages (p. 149), are disposed in shallow ' rafts', no more than a yard or two thick, through which the nets in each instance pass perhaps for only a second or two. Assuming such a disposition, and assuming too that only one such raft existed in each vertical horizon, then the time correction applied in the case of the shorter-term TIME STATION O- SO- 100- 250 500- 750 1000- N5 OF METANAUPLII I400- -1800 1104 2610 O- 50- 100- 250- 500 750- 1000- I800 - 2200 1965 655 637 1144 1138 1545 2345 1671 2600 1713 1994 26031 63 517 34 557 1515 195 I05I 10 106 5 8 830 22O0 - 0200 1492 520 618 854 I0200- 0600] 647 24 6 20 184 0600-lOOO |WI97 638 823 !?: 115 7 43 looo- -woo 636 + TIME STATION O -SO -lOO -250 -500 -750 -lOOO N5 OF METANAUPLII 12 10 2 II 52 95 13 67 36 - 13 9 3 2 440 461 19 21 1215 4720 116 66 51 485 36 2 53 245 78 4 - 35 - 5 112 63 39 41 lO 167 115 5 I 90 119 97 4 165 69 2 31 47 20 22 59 148 II 10 6 142 49 196 29 5 5 - 35 4 7 5 351 - 20 - 94 36 ISO 28 282 2 7 2 5 - 31 2 I O SO lOO -250 500 7SO lOOO Fig. 12. Four-hourly vertical distribution of the First Calyptopis based on the catch-figures shown in Fig. 6 uncorrected (histogrammatically) for duration of haul. upper-level net hauls would be unnecessary since the nets in every instance of striking a raft would strike it for only a second or two and so produce samples which, whether the haul were long or short, would for all practical purposes be comparable. The four-hourly vertical distribution of the First Calyptopis, when co-existent with Meta
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