Spolia Runiana.-V. Summary of Results of Continuous Investigation of the Plankton of the Irish Sea during Fifteen Years
Journal of the Linnean Society of London Botany
History in the University of Liverpool. (PLATF: 7 and 2 Text-figures.) [ b a d 2nd March, 1922.1 INTRODUCTION. TEE history of this investigation, which has now extended over fifteen years (1907-21 inclusive), is briefly as follows :-After collecting nnd examining ermples of tnarine plankton in a casual and sporadic inaniier for over quarter of a century on various parts of the British coast, in the winter of 1905 I hocame impressed with the view that the only hope of solving some of the
... some of the problems of the plankton lay in a much more exhaustive study of a much greater niumber of samples taken as frequently as possible throughout the year at one locality, or sories of localities, and extending over several years *. My connection with the Port Erin Biological Station and the staff at work there and in the Zoological Department QE the University of Liverpool afforded the opportunity of organisiug a scheme of co-operative research, which later on became cryshllised into six "official" hauls of the plankton net per week throughout the year, and a much greater number of li special " hauls (often ten or a dozen per day at sea, and amounting to as many as 36 hauls, in a small area two miles in extent, on one occaeion) during certain critical months of the year (March, April, July, August, and September) when the plankton was speciuily abundant or was rapidly changing in character. The "05cial" gatherings were taken by the staff of the Biological Station inside Port Erin bay and consisted on each occasion of two horizontal eurface-hauls ncross the niiddle of the bay, about helf a mile, and one vertical haul, from 6 fathoms, close to the buoy at the entrance. The "special" hauls were taken by myself from a steamer both inside Port Erin bay and also a t fixed "stations" in the open sea at distances of 3, 5, and 10 miles from land, with occasional days in the deep water (60 to 70 fathoms) halfway from the Isle of Man to Ireland. For these purposes, during the summer of 1!106, I chartered the steamlauncb 'Madge,' and used her for a preliminary survey of the ground and The research has, however, extended over a much longer period than ww at first eontemplated, but new developmeuta in the work kept opening up, and the value of cumulative evidence was impressed upon toe. It was felt necessary to have thousands of samples to deal with and a number of yeam to compare. LINN. J0URN.-BOTANY, VOL. XLVI. I I42 SIR W. A. HERDMAN : RESULTS OF CONTINUOUS the methods*. I then found that for facility of working and efficiency it wns desirable to have a vessel and crew devoted specially to the work and on board which one could live and make more extended cruises, and keep all the necessary apparatus, &c., for working various kind: of nets and for preserving and examining collections. SO from 1907 to 1914 (inclusive) the iiivestigations were carried on from the steam-yachts ' Ladybird ' and 'Runa' (1911-14)-especially the latter larger boat, in which with the most efficient help of the skipper Mr. James Urebbin we had the necessary gear for sounding, dredging, trnwling, tow-netting, and the working of various special nets, water-bottles, &c., arranged so as to work smoothly and rapidly. During and since the yoars of war such continuation of the work as was found possible has been carried on from khe 27-foot cutter motor-bqat 'Redwing.' I n the case of most of these special collections taken from my own boats I was able to make a hurried microscopic examination of a sample froin each haul in the living condition, and take a few notes of the nature and quantity of the pthering and of the-prevalent organisms. I n all cases, both "official" and bbspecial," tho gatherings (except when for safety they bad to be pr& served on board the yacht) were dealt with, fixed, bottled, and labelled by Mr. H. C. Chadwick, A.L.S., at the Port Erin Biological Station. fie collections were subsequently worked over microscopically by Mr. Andrea Scott, A.L.S., and the numbers of each organism identified were counted or estimated and entered on our printed tabular forms, which were then sent to me for analysis and comparison with tho other weeks, months, and yeare J the accumulating series. I n all this work at Liverpool I had much help from my then secrotary, Miss H. M. Lewis, B.A., who supplied me withih totals and averages I required, and drew up tables and graphs under my direction. The results of each year were published annually in the Reports of tbc Lancashire Sea-Fisheries Laboratory at the University of Liverpool t for the years 1907-1921 ; but, for the most part, general results and conclnsiom were postponed until the completion of the series. Now that I have retired from active work at the University and the direction of the Port Erid Station, and have handed over the collection of upwards of 7500 plankton samples, and a corresponding number of tabular records, to the Dcpartmed of Oceanography-wlierc no doubt, in the liands of Prof. Johnstone, thq will undergo further analysis and, 1 hope, yield good results,-it may be oq some interest to those who are conducting plirnkton research elsewhere tha I should give without further delay a brief' summary of our records and goma account of the conclusions a t which I have arrived as the result of &c fifteen years' " intensive " work. * The reeulta of thnt work in 1906 me not included in this survey of fifteen years, t Trans. Biol. SOC. Liverpool, vols. xxii.-xxxv. * The full list of between 20 and 30 organisms for each net is given in our first Annual Report, for 1907.