The Impact of Tegula Pulligo, Gmelin on Tissue Loss from Macrocystis Integrifolia , Bory - in Barkley Sound, Vancower Island A$ British Columbia

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38314 .rP (I

National Llbrary B~bliothCquenatlonale CANADIAN THESES TH~SESCANAD~~ES iS of Canada . du Canada - ON MICROFI&~E SUR,MICROFICHE r' - / - I -. P 1.

\ Glyn ~ohrk$ARP NAME OF AUTHOR/NOM DE L'AUTEUR -- - - \ I rp ' The impact of Tegula pulligo, Gmelin on tissue loss from \ TITLE OF THESIS~FITREDE LA THESE , \ I Macrocystis ,integrifolia,, Bory in Barkley Sound, ~kcouver 1 #I e' * " 1slapd;b British Columbia.

d' ,+ ,+ i..-*- Simon Fraser University UN IVERSITY/UNIVERSIT~ 3 q DEGREE FOR WHICH THESIS WAS eESENTED/ Master of Science GRADE POUR LEOUEL CETTE THESE FUT PR~SENT~E 1974 YEAR THIS DEGREE COMF~RRED/ANN~ED'OBTENTION DE CE ,GRADE Dr. L.D. Druehl NAME OF SCjPERVISOFt/NOM DU DIRECTEUR DE TH~SE I. I

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9 4 - - - - 4- ? '7 0 I I 6 ' THE IMPACT OF TEGULA PULLIGO, GMELIN ON TISSUE LOSS FROM MACROCYSTIS INTEGRIFOLIA , BORY - IN BARKLEY SOUND, VANCOWER ISLAND A$ BRITISH COLUMBIA

GLYN JOHN SHARP

, " Dalhousie University, Halifax

A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT a OF THE -REQUIRFSENTS FOR THE, DEGREE OF MASmR OF SCIENCE

in the Department

Biological Sciences a -

t @ - Glyn John Sharp / , .,r ~iionFraser University

August 1974

A11 rights reserved, - *is ees-is ymaynot-be-r;eproduceb- T- in whole or in part, by photocopy or other means, without , -1 permission of the Author - - APPROVAL -

Name: Glyn John Sharp

Degree: Master of Science i I 4 - $ Thesis Title : The Impact, of Tegula pulligo Gmelin on Tissue Loss from' 4 1 + Macrocystis integrifolia Bory,in Barkley Sound, Vancouver

I.. Island, '~ritishColumbia:

.w. .L4 .-....Y...... -.; ...... \ L. D: Druehl w. C. Austin - Senior Supervisor Supervisory Committee- 2'

...... C...... T. H. Carefoot 1 - - - -- R.M.F.S .' gadleir Supervisory Committee ~epartmentalExaminer

.d Date Approved: Name: Glyn John Sharp I Degree : Master of Science +? d Thesis Title: The Impact of Tegula pulligo Gmelin on Tissue Loss from

-d Macrocystis integrifolia Bory in Barkley Sound, Vancouver

Island, British Columbia. *-:

Examining Committee :

L Chairman: Dr. R. Brooke

L. D. Druehl W: C. Austin Senior Supervisor , Supervisory Committee

. T. H. Carefo* R.M.F.S.' Sadleir Supervisory Committee Departmental Examiner i ------

Date Approved : .

iia PARPAL COPYRIGHT LICENSE

J /-, 5 4

I hereby grant to Simon ~rkerUniversity the right to lend . f my theais or dissertation (the title of which is shown below) to userq , of the sirno;\ ~raser3niversity Library, and to make pactial or single 4 -.. t copies only for such users or in response to a request from the library

" :9; of any other university, or other educAtiona1 institution, on i-ts-own . ------" I +#& 6% behalf or for one of its users. I f-urther agrec that permission for

+ " multiple copying of this thesis for scholarly purposes may be granted - by me or the Dean of Graduate Studies. It is understood that copying

or publicat ion pf this thcsi s for financial gain shall not be allowed 23 without my wr d ten permission.

- it le -of l%esTs /~l'ssertation :

Island, British C?owia I

Author: -.- - -- - . r - ;? - (signature )

- Vancouver Island contain numerous invertebrate herbivores. A prosobranch

I gastropod, Tegula pulligo Gmelifi was found tovbe numerically dominant

LL - ---- throughout the year in all surveyed kelp beds. If was highly motile but .

did not make any mass migrations within the study period. t Laboratory feeding experiments with T. pulligo indicated that

consumption'of tissue was not a satisfactory indicatox of grazing impact.

A significant amount of tissue was lost due to she incidental effects of 0 grazing. In .the' field grazing and water motion acted together to

accelerate the loss of plant tissue. . .I Growth of 5. integrifolia was assessed during a period of maximum

- - " growth in -the kelp-bed. - The-lafna was used to assess production, since- -

grazing and erosion-acted most directly on this frond structure. The

laminae grew as a moving belt of tissue up tq.24 days after they split ,.- &om the qp$&l scbiitar. 1, In a small (100 m-square) kelp bed the plant and herbivore population

pulligo consumed 2.3 -+ 1.6% of lamina production, but the interaction of

L its grazing with erosion cause3 a low& 55F38.53- of Ia- produiti'on. . i 4:

I iii 6' 6' I -.&-&- - I would like to thank Dr. L.D. bruehl for his confidence, financial 5

ri \> assistance and help with manuscript preparations; Dr. W.C. Aystin and

Dr. T.H. Carefoot for criticism of manuscript: Doug Kittle for heip in " - -

b L the field and all my diving partners including Dan Pace, Chris Lobbq ,

I and students of the Bamfield Marine Station, Summer session, 1973; *Judy

D - Murphy for assistance at various stages of my work; Karl Ostroyl

' Frank Wick for help in the design and construction of under-

water &ipment; Ron Lo~igfor photographic work; Audio Visual Graphics

department for drawn figures; and lastly, but not least, the people of +. - \ Birmfield for their Gelp and kindness. 'TABLE OF CONTENTS

- 0

Page

'~xaminingCommittee approval

Abstract , -. iii

Acknowledgements

-Table of Contents

. +\ List of Tables ia

List 'o•’Figures xii

STUDIES ON MACROCYSTIS TNTEGRIFOLIA

METHODS '

General dis,tribution of g. in Southeast

Barkley Sound

Growth measurements

Stipe length and blade number

Lamina length and width increment, duration and I RES UL~

\ ,\ > . General distribution of -M. integrifolia in Southeast \ .. Bark1h sound \ ~rdwthmeasurements 5 - . JO d

@ Q Stipe length and blhe number 10

Lamina length and width increment, duration and

pattern of growth - 14

; Biomass *per unit area of lamina ' -- 20 DISCUSSION.

METHODS ,

%. General distribution of T. pulligo in southeast

seasQnal distribution pf T. pulligo and other' .

herbivores

The Gpulation struction of -T. pulligo

~otilit~

. Wility and substrate preference of tagggd x. pulliqo

Motility of tagged 2. pulliqo on M. inteqrifolia

---- Kelp bay infestation experiment

- 7 - -

' Motility as related to water movement

Feeding behaviour Page -

F- .. .Feeding experiment with two species of algae

Diurnal feeding vperiment

1 Long term feeding experiment . . i Consumption as a function oaf temperature =

Feeding frequefidy

G era1 distribution of 2. pulligo in Southeast R ' / Barkley Sound

Seasonal distribution of ;. pulligo and other herbivores

-I -T. pulligo population structure .* . Motility

Motilitjr and subseate preference of tagged -T. pulligo Motility-of tagged -T. pulligo on -M. integrifqlia Kelp bay infestation 'experiment

- ~otil,&ty,asrelated to water movemept, *- + T.6, , s P . . Feeding .behaviour

Feeding exper,iment with two species of algae%

Diurnal feeding experiment

Long teq feeding experiment

Consumption as a function of temperature

- Feeding frequency -- - -

DISCUSS ION i. Page

67 :. METHODS * , i Grazing damage t. + Frond degradation, grazing and erosion F Drift -

I- IRESULTS .=. t / I.

/- Grazing damage 6 Frond degradation, grazing and erosion '

Drift algal collection

IXTAILED STUDY OF A KELP BED

METHODS

RESULTS

Calculation of T. pulligo grazing impact at study site 102

+ ., viii \ . - - - ~- -~~ -- a

. - /': ~ . 7. / " 1''

-. LIST , OF TABLES I ,' \ 4, ' . , , .: s

--, 2 A e * Table I Frond Sample- ~;ou~sUsed in Growth Rate 'A? 4

~kperime.nts:-~_qssu Plateau Kelp Bed # . - - , - ,% -' -r ., .- - - + a - -- - / Table 11 ~ocation-an&Mave Exposure of Temporary

Transects in the General . -T. pul1l"go ~istiibutionShown in Figure i 2,

i Y , Eleven

.&* "' , -,

Table I11 - Location and Wave Exposure of Permanent ------sg -- -- Transects and Deta&ed- Study Hi-te-shown

in Figure Eleven

Results of the General, Survey of T. pulligo . . - Distribution.in Spytheast BaYkley Sound

Table V ' , Basal ~iam"eterof -T. pulligo

Table VI Ross Islet Tagging Experiment

Table VII Scott' s Bay Tagging Experiment ,'; s . .Table VIII Kelp Bay Infestation Experiment 5 3 1 "5 dl r <" A

.-- Table IX Feeding Experiment with TWO Species of - Q. B 3- Algae . . 4 455

4 * * DAurnal Feeding Experiment . .. . 56

A Table XI Cpelete Factoral Anova of Long Term +"

Feeding Experiment Results

*'l > - Table XI1 Consumption Rate Experiments at 3

Temperatures ' -?.-- ' 'j - Table XI11 Selected Herbivore Feeding Rates .' 4 ------* - ,'

Table XIV Grazing arid Brmion ~reliminary~&erime?t

Number 1. ' , % 72

\ Table XV Wind Velocity and ~i'rectionat Cape Beale .-- Ihking Grazing arid ~rosio~~Expe~iments ' .* - ? 2 and 3 79 b

Grazing and Erosion 5x~erimentNumber 2 80 Page ------A P @ 3

Table XVII Graz ing and E~~sionExperiment Number 3 81 -. *_

Table XVIII Drift Algal Cqllections ' . ,

Table XIX Cape Beale Light B.C. Percentage Frequency ?

. A - ' -1 ... ' Wind Direction (and Ga&ms).. and Mean Speed -

Table XX p-' Herbivore Survey and Harvest l?esults RDss ap &.- . - Islets Platgau. - Kelp Bed Study Site ,- 9 7 .,. * .* * - .>. -, A - , .C . . . .q\ -z - J *-y\ . - .% 1 := -. - - .,?A-5 ... : ';-4 .... T LIST OF FIGURES

Page

Figure 1> A schematic diagram of a -M. integrifolia , - sP , r , frond showing the nomenciature of structures -

and ~egions 5

I 8

Figure 2 The distribution of two forms of-M. I - 7. - 1- integrifolia as observed in a survey < covering southeast ~arkle~Sound in ~ul~,*

1971 (Druehl, pers. comm.)

>,A with the length of 56 stipes measured over .,

30 day periods, during July, fiugust and . . s, September at the Ross Islets Plateau Kelp

bed. The curved line was drawn by hand 11

Figure 4 Variation in thevnumber of blades on a

4 stipe with the length of the stipe. Blade

bed on 57. fronds durinG July, ~u~u/stand--- Page

a September, 1973. The formula describes ,

f <- ,- h the line through the points - 12 3 C

1 * with the stipe length of 26 fronds' & re * , , .+ 'I measured over 30 day periods in August , . 'E and ~eptem6erin the Ross Islet Plateau

Kelp bed. The formula describesathe line , ., ' r' through the points 13 , d ? r) -a I

$ Figure 6 Variation of the distGl movement of holes J i ------

punched in the lamina with initial blade i n positi-on on five fronds over a 7 day periqd '? ,. -9 . . -in August at Ross Islets Plateau Kelp b5dJ,-- . & J The most apical blade is the first

I independent blade. The distal movement

as the 1

- elongation 15 d / # *I -4 31 ,f A , f . C - -- A- The relative growth af 1 cm diameter holes F67 ,f , -= d. --- punched in the laminae of adjacent blades

over 22 days '/ Page

Figure 8 The distal1 rate of movement of holes 'punched '

in the laminae of the first independent P

blades with 4 - - 8% day intervals &om first , " measur-&e;t. Distal movement of basal

- d ,P holes was interpreted as the minimum rate of

l&ina elongation

Figure 9 . Variation in the rate of hole movement (elongation and widpning of the laminae) - with the positibn of the hole from the base

of the lamina over a '5 day period, on the ' .

laminae of the first independent blades of ------

, 16 fronds -

Variation in the fresh weight of -M.

integrifolia laminae with their position

\ on the f-rond -

Locations of ~tudysites in Southeast \-,

- +arkHotin* ~aeotrver-~&andL

xiv i Figure 12 . Petri ,dish lids (100 nun diameter) with -- -M. integrifolia laminae glued to their

surfaces 34

Figure 13 variation with time of temperature at

- one meter (:--) and five meters (-1

in B,mfield Inlet through 1969-76. + -

-A Figure 14 A schematic profile diagram of the Scott's --,./' : = Bay, China Hat Pass and Wizard Islet 2- FA- permanent transects showing -ttae macrophyte_--'/ "? - ---+ * * d campy in the summerseason ------*3 ------" .%- -. -40 -- n a

Figure 15 A schematic profile diagramLof the Kelp , -

Bay permanent.transect for early fall, \

winter and early summer showing the

rmacrophyte cover and conspicuous members

of the understory 42 * f I

Figurer6 -- Theist u-uf io-T - pullsgoTthe

Bay transect from Sepeember, 1972 to 3tttyi- ---

1973 - 43

,' K--L xv ---- - , . <' I 1 Figure 17 The distribution 0.f -T. pulligo ow / ,the China Hat P ss transect from

a.?p September, 1974 io July,, 1973 ,-1 _ 4 4 + - -P , - - , B Figure A8 A-L Histograms showing &he size dfstribution = - - of T. pulligo colleste8 from a cqbble . 4 - substrate and from.~.- integrifolia 't during 1972 .to 1973 at Kelp ~a~ 45

i . , A-L Figure 19 Histograms showing the $ze distribution . + of -T. pulligo collected from a shell < 7" sand substrate and on M. integrifolia ------2------*- - -- - * r - < during 1972+a&&33 at China Hat Pass 46 --=' - a. - Figure 20 Ross Islets tagging experiment search

and deposit area for tagged 2. pulligo

il Figure 21 Variation in the feeding. rates of T. 9 - a * 4b pulligo with time at 10 .C. ---- grand =?

I 81

mean -of -daysLLLa_8-- - - - + 5 ,-"ed-z- --- ' 4

xvi . - .. Page . . 2 . I. k .

C. . . - Figure 22 Grazing and erosion interaction experimen:

Figure 23 The grazing and erosion experimental i

site located in Scott's Bay 71 rj -

' Figu~e24 .cbasacteristic grazing-damage of isolated 4 T. pulligo on a g. integrifolia lamina 3.. , ;-. " Figure 25 M. integrifolia in var?gus states of * - - t , &SZ degradation osllected in May

------Figure-26 - Variatic?f;in the percentage o•’tt-all- - - $--' b E blades missing more than 80 percent of >J -- * their tissue with the lerlgth of frbrPd 77 - _,/- - - ,' .- Figure 27 6.Fragments of drift algae removed from

catch buckets at the Ross Islet's Plateau

kelp bed in October to ~ovember,1973 . 83

------Figure 28 The moveable'grid system used at the,Ross

Islets detailed study site to subdiviiie

5 x 5 m sectors into 1 m quadrats . .

- .~.- - -, - - .- -.--- ~ - A . - --L

. ."F . . . *x ,<* * :> ; % ...... , P I.' -7. + * , . .. -. *, Page

L Figure 29 The two major substrate- &es found at

7. the Ross Isle- detailed'flstudy site

Figure. 30 The topography of the Ross 1slets Plateau

I kelp bed study site

Figure 31 to represent plants and ,.$ .. herbivores in figures 32, 33 .F?

The macrophy t&"canopy at the Ross Is lets 2 5 - 4 Plateau kelp bed study site including ------

large herbivores on each plant in June, 1973 94

Figure 33 The distribution of large herbivores on . e the bottom at de Ross 1sleG Plateau

kelp bed June, 1973 -

Figure 34 Population structure of -M. integrifolia

fronds collected-at thPRoss-lsle~ud~

=a site from August 20 to 23, 1973 - 98 - - P Page . ,

Figure 35 His togram the size distribution (basal ,

diameter) -T. pulligo collected from 5 substrate the Ross Islets study-site

- - A &? * .\ .- e z7 . . 4 f - . * - 1.. 1.. -? .,+. -

the size :$istribution, (hasfi Figure 36 Histogram ' + dimeter ). -T. pullr& collected on -M. integrifolia harvested at the Ross Isle?s study site

xix INTRODUCTION -

The kelp bed (Macrocyst.is, C.A. Agardh, 1823) communities on the

. Pacific Coast of North America contain many separate plant-herbivore

associations 2 f have investigated the relationyhip between the brown ., " - alga Macrocyetis integrifolia Bory (Order Lminariales) and associated .- 7 A 5 herbivores particularly the prosobranch gastropod Tegula pulligo Gmelin . . , ?. (Family Trochidae) in.Barkley Sound on Vancouver Island, British .. 4i Columbia, Canada. 1 B Macrocystis integrifolia grows inshore from a meter above 0 tide

level (Canadian Datum) to 3 meters below and ranges from Point, Conception,

California to Kodiak Island, Alaska, U.S.A. (Druehl, 1970; North, 1971;

" Q' Wom&rsley, 1954). Tegulagdigo is subtidal and ranges from Sitka, ..

Alaska to lower Calitmia, U.S .A< (Griffith, 1967) ------. Species related - --

to this plant and this animal have received considerable attention from

researchers. North, (1957-1974)- has led a research group investigating Macrocystis pyrifera (Linneaus) A. Agardh in California. These workers

- - - - studied aspects of ecology, biochemistry, growth, physiology, .. .. .' reeroductjon and faunal associations.- Independent studies were conducted t - C 3 'earlier, for example investigations of faunal associations in the kelp beds -- B - 4 d .- e.

-z have been largely 19 ted to growth (Scagel, 1947; North, 19731, 7 \ 1 morphologicdl variatidn (Pace, 1972), chemical composition (Wort, 1955), :t +$P and a single calorific value (Paine and Vadas, 1969). -9 Tegula funebralis (A. Adams), an intertidal neighbour of ;. pulligo

has been the subject of many studie~: physiology (~aliiand Giese, 1959); - - I & growth (Frank, ,1965); feedigg rates (Best, 1964); energetics (Paine, 1966);

predator prey interaction (Paine, 1969) ; and locomotion (~iller,' 1974) . ". ' The limited' access to T. pulliqo has restricted research to a few studies.

2 A class at Hopkins Marine Station, California performed short projects on 5 * 't the following: respiration, predation ant distributi.on*(~ear$e,1972).

bwry (1974) studied the distribution of Tegula spkcies in a M. pyrifera4

The major pur$ose of my study was to assess the impact of ;. pulligo

on the natukal loss of -M. integrifolia tissue. During this I also

noted the distr-ibutions of the other herbivores. The investigation was , , in four parts: local -M. integrifolia distribution and growth; ;. pulligo's

J distribution, population structure, movement and feeding behaviour;

interaction .of the plant and the herbivore and a detailed field assessment 0 of -T. pulligo's grazing impact.-

The first part of the study involved obtaining production rates of

plant laminae since the laminae were the most important fmnd stkucture in

the plant-herbivore relationship. Further, I investigated ddistr-ibution t

4 of the plant horizontally and vertically as well as rJle phenology of the

kelp bed throughout the year.

< The-second park of my studies consider~d,suchquestions as: what is ------the distribution of x. pulligo and other herbivores vertically and

- horizontally; do the-herbivores remain in the kelp bed thraug&ut the G< year? Further, to establish a feeding rate for the snail answers to the

- folldwik~questioGs were igquir*: what is the feeding period. feeding. -* -5 *

1 frequehcy, the effect of light, temperatme and food preference?

7., j5 t Initial laboratory feeding experimyents incficated the tissue consumed was

only part of the total tissue lost to the plant. ; .

T <- - This'ddditional tissue loss led to part three of this study involving the interaction of the grazers and the &ant ofin field. *: , ,:Specifically, doe5 grazing weaken tissue so it is more-susceptible to -c> ,erosion by water motion? What are the characteristics of grazing damage

and its extent in the field?

The fourth part of the study was the calculation a value to 3 %?*T fhct the *impact of 2. pulligo grazing on M. integrifolia. Kelp bed $<. compJJ&xity prevented-the- application of a general model for the plant- I' I' -* herbivore system over an &;tended p&iod and area. Theref ore, the. value .*-* 5 -. was calculated in refetence to a 100 meter square area within a large kelp

bed and applied to a one month period of maximum kelp growth.

This thesis is presented in four major sections, each consisting of I '

specific methods, results and discussion. They are preceded by-general . c. 1 - - methods and followed by a general discussion. C . GENERAL METHODS

All statistics- and statistical tests_computecLfrom~data witAhane----

exception used standing routines.from STATPKK in the A.P.L. (A Programming-- - Language) of_ Simon Fraser university Computing Centre. The exceptimn was

the t-test for the-equality of means which was designed by Sokaland-- - &.a - - -. g Q *. , i A------4 - - h *'&kf (1969). All tests for the equality of statistics we%7,----- donducted -i; fh +.,, I. '-,a% the 5 percent level of significance. $ -, 1.. "p 8 - ~aboratorystudies were carried out in theLBamfield Marine Station,

< * . ~a&field,:?~.C.with one exception. Unless otherwise specified these & B * * %, ' e&, experiments? took',place in an open seawater system. Organisms employed --- -J , - ?,e _ 3. T& - in laboratory experiments were transported to the open seawater system in ? -- a ', ' *i-, plastic bags within 1 hour, All field studies were coMucted in ~arkle~ Fw f Sound, within a 5 Km radiu; of the Barnfield Marine Station and employed > t i % - SCUBA.-- e = _ i-

i d i STUDIES ON MACRO CYST IS^ INTEGRIFOL~A i ?" I CI 1. -? L $.

I -

METHOD$ *% 3

*r General distribution of M. integri-folia in Southeast Barkley Sound. i . i

- - F During July 1971, a-presence~absencesurvey was-conducted for the-- J distribution of -M. integri.fo1i.a (Druehl, pers. corn.). Presence or " B absence was estadlished by surface and underwater reconnaissance. .. - .-5 +

. < 'J7.- i Growth Measurements - b- a

Figure 1 illustrates the morphological terminology employed for 7. . : _ -M., integrifolia in this thesis. .z U r -\ k ,, --

. , Figure 1 4 schematic diagram of a M. integrifolia frond I :: showi* &.e nomenclature of structures and 4 / regions ,I

------

,' 2 Stipe Length and Blade Nder - I _?

-i v *, .r J , All,yF and blade measurements were made underwater with a meter

,/- /=- , stick~?'30 centimeter rule. Stipes and associated bladbs were i

. .. __ .*..-- -- identified with surveyor ' s marker tape lettered with waterproof ink.

The tape was tied loosely at;. the base of each stipe or at an internode , to prevent tissue damage. The- groups of fr6Lds bsed in stipe

elongation and blade number measurements with dates or measurements are I 6 ' listed on Tale (I). Stipe length was defined as,-t%e distance from the a 9. most recent terminal slit to the juncture of the stYpe and holdfast. -1

Blade number was defined as.the total numb'er of independent blades plus

the number of terminal slits per frond. Accuracy in measuring underwater '

r decreased with the size of the frond. Blade counts welie estimated to be - '$ '$ - - appr~ximate-ly within 10% of the true number and length t6 within 10%of + i the stipe length.

------*. \ I. \ \ Y Lamina Length and Width Increment, Duration and Pattern of Grcwth ,,

A paper punc was u t 1 cm diameter holes 2-3 cm inside the - periphery owtin ncrement was defined as the change in

o centre distance een two opposite holes. Length increment

was defined as the change istance bktween a hole centre and the base

of the lamina (~ribb.1954) . holes were punched in the meristemtic * area of thefamina. the holes gqew in diameter but did not move along the

------pp \ lamina. To avoid this problem the holes were subsequently punched at - - least 5 cm from the base of the lamina. Four separate groups of fronds

were used for study'of lamina growth. The sample groups and procedures I I 1 I b TABLE I I I -- Frond Sample. Groups Used in Growth Ratd. 4, Experiments ROSS Islets Plateau Kelp Bed I

% Plant Structure ,. Purpose Dimens ion Method Position Sample Ddtes of I+a of Holes Number , Measurement \ on Lamina

\ & ------epe I Rate of- Length "'DL-tance from thee* None, ' I -.--80 -- -- -1 _------longa at ion base of the stipe _---I - ---1 . -&-----_ - . _- \-.J -- - the last terminal- - ',-----.---->--- slit ' -, _C2/-*------\-----. Blade Number per Total F&ifl-&u&pendent blades Noie 65 B '13/8/73 & unit length number plus termi3iZl-sli$s * '2 10/9/73 counted -1 , ----\. Blade Rate of Total All independent blades None " 18/7/73 +4, addition number plus terminal .slits %lL%--+14, +20, . t counted +2 4 ------\i Lamina D&ation of * Length Holes in pairs on. Base 80 24/6/73,. $2 1 >-': growth and & width laminae of the mid to a b mean rate basal region of fmZd * I - I1 Lamina Duration of Length Holes in pairs on grawth and & width first indehndent mean rate laminae , u . Lamina Relative Length Holes in triangle of Base 50 13/8/73 L growth of & width 4-5 adjacent laminae d +7 ~ adjacent , lamina e \, ^\. Lamina Pattern of Length 3, hole pairs on first Middle '& 11/9/73, growth width independent laminae Base 16/9/ 74 >A, 1.1.'" 4 I. 1 i

i r

& ', , '\ i /, -- d relative growth and mean growth-rate of

\ . \ L Biomass aer Unit Area of the Lamina m Twenty--three fronds-ranging from 0.~25 cm to 6.0 m in length were --

collected from the Ross Islets ~lateaikelp bed in June, 1973 (~4~.2) .

The apical lamina, first independent lamina, a mid region lamina and

basal lamina were removed frm each frond. Tke fresh blotted weight of . - each lamina was measured on a toploading Mettler model ph200 balance to

0.1 gm. The perimeter of each lamina was traced on newsprint fpr later

reference. Nu attempt was made to include holes in the lamina, unless

they exceeded one third of the width. The area of each tracing was

calculated by a Salmoiraghie Model 238 planimeter (Salmoiraghie Instruments, .;' ------t 2 Milan, Italy) to 0.1 cm . Theweight per unit area was then calculated

/ -,','/ for each lamina grouping ., . l-2 ,..? ,,- -

--- -RESULTS* 5 General distribution of -M. integqifolia in Southeast arkl ley Sound. 1 H TWO forms of M. integrifolia were distinguished, in the 1971 survey

(Fig. 2, Druehl, pers. comm.) . There was an erect form which floated at

the surface and a low-lying form which laid along the bottbm. The

prostrate form was restricted to the sheltered northern end of the Trevor - -

I A channel on silt covered bottoms. Macrocystis integrifolia was present in

moderately exposed to sheltered areas where there was a stable substrate s Zd C and good water circulation. Figure 2 Th,e distribution of two forms of -M. integrifolia-

a? observed in a survey covering southeast '

Barkley Sound in July 1971 (~ruehl,pers. comm.)

Scale: 1 cm = 1 km

- - -- - M. integrifolia erect &r$M. htegrifolia prostrate i Growth Measurements

, Stipe -Length and Blade Number . - TRe rage of stipe elongation increased with the stipe length up

to approximately 200 cm. Then fhe rate of grawth decreased by 30 -

, percent for each additional 100-150 cm of stipe length (Fig. 3).

A linear regression line for the data had an R value of 0.16 and accounted

for 2% of the data variation indisating a poor l$near..'relationship. *- f .f Theref ore a curve&:line was fitted by hand. Although a decrease in =- * - i

growth is suggested beyond the 200 cm length position of the line is in 2 - I doubt due to the paucity of measurements:-

There was a constkt relationship between the length of stipes and

the number of blades (Fig. 4). The linear regression line was a good

fit to the data with an R value of 0.9 accounting for 81% of the data

'variation.

- -- - ThereIwas a slight increase in-the rate~f-bladeaddition-over the . - - - -

range of stipe lengths (Ef;ig. 5). The mean rate of blade addition for

the sample qas 0.4 SD -+ 0.2 blades/day. A' cuyvilinear relationship may be argued for the variation in the rate of blade addition with initial

stipe length. Hawever, the previous blade number results hhowing there

is a constant number of blades per unit length regardless of length

indicate abinear relationship exists between the two sets of data. The ,/ R value for these data is 0.35 and accounts for only 12%of th:e variation. i - - - ,-- d t This is a poor and for any stipe length the rate of addieon can 3 * i .1 dZtX cm -4 range from to .8 blades per day. AdditloIIaI beyond 200- s€ipe Y length is required-to prove this relationship. *- '* Figure 3 Variation in the rate of stipe elongation with

the length of 56 stipes measured over 30 day

periods, during July, August and September at 4

the Ross Islets Plateau kelpbed. -T+e curved- - - - -

line was drawn by hand

---- line in doubt due to lack of points' llb i Figure 4 Variatio~in ,the number of blades on 'a stipe . -L '.with the length of the stipe. Blade counts -

'. were made in the Ross rslets kelp bed on 56

fronds during July, August and September,

' 1973. The foknula describes the line

through the points

Figure 5 Variation in the rate of Glade addition with the / stipe length of 26 fronds measured over 30 day /

periods in August and ~e~temberin the Ross 1slet

Plateau Kelp bed.' The formula describes the

line through the points

f , ~ r

+&&mi&? ~en~#and' Width Increment, Duration and Pattern of Growth '

i The results of the two approaches to the problem of frowth I + duration replicate onedother to some extent but illustrate clearly ,

the interrelationskirp of blade position on- the stipe and the- growth . - activity .d? the lamina. I 4 1 I I - I The more basal a blade's position on the stipe the slower was the

/ , rate of lamina elongation (Fig. 6). After 22 days there was no lamina

' elongation on any of &e tagged blades. ~ssumjng.- a blade additibk rgte , of 0.4 blades per day; at sevep-days folXming the initial measurement at " ' least 2 blades were added above the tagged blade. The diameter of the 4 , A punched holes also-?%owed dramatic differences in the growth of adjacent , .i . . .. B lamina (Fig. 7) . - I Holes punched near the meristematic 5egion of the first independent J blades ceased distal m&ement between 21 and 24 day&- 4Fig. 8). The mean ,- .k - - rate of elongation was 1.9 SD -+ 1.5 cm per day over 2'2%a% days. The V, -. changes in the rate of hole movement over time can be :related to the ---r- - ,. b lamina growth pattern measurements.

The- pattern of growth in length along the lamina was slaw in the I , & W.' - meristematic region and increased taward the middle region of the lamina

(Fig. 9) . Only one lamina was initial* punched beyond 22 cm; (at 29.5 cml -c * --% its distal movement 'relative to the base was less than 1 cm per day.

- - _,This single tneasurement suggests. a trend to the cessation of grbw& in the - 4- it distal &

overallcra$e of elongation was 1.9 SD -+ .9 cm/day. Figure 6 variation in,,the distal movement of holes punched P. L in the lamina with initial blade positibn on five I fronds over a 7 day period in August at Ross

Islets Plateau kelp bed. ~hdmost apical blade t is the first independent blade. The distal

mobement of punched hole's is 'interpreted as the Z a'+ L

range cm/day fl' - >* -

3'" * - mean cm/day A 1 .","- w I Rectangle, vertical axis , SD cmBay - ,< a N = 5 per blahe position ,' f P

The relative growth of 1 cm diameter holes C punched in the laminae of adjacent blades over 22 days. a. The most apical blade is the lower

blade in this figure b. The most apical blade is the blade

on the right in this gigure

4 '. Figure 8 The distal rate of movement of holes. punched

r 1 in the laminae of the first independent blades

with 4 - 8 day intervals from first measurement.

+ *. _ Distal movement of basal holes was interpreted . . .

as the minimum rate of lamina elongation

time period N

vertical lines rany-b-m@ay

horizontal lines . mean in m/&y '

/A rectangle vertic4 ,, ~ -- +.

.b'

.. .. LC. - Figure 9 Variation in the rate of hole movement I (elongation and widening of the laminae) with

- the position of the hole from the base of the

lamina over a 5 day period, on the laminae of

the first independent blades of 16 fronds.

vertibal lines range in &/day

horizontal lines mean in cm/day

vertical axis, rectangle LENGTH INCREMENT (C~/DAY) WIDTH INCREMENT (C~/DAY) The mov,&ment of opposite holes away from each other decreases as 1 I the holes move toward the distal end of the lamina (Fig. 9). ow ever, i to translati the movement of punched holes into actual width ineremints / of the lamipa, I assumed the lamina to be a moving belt of tissue. I Therefore $he mean rate of width increment of 0.43 SD -+ 0.3 cm/day was #. i - applied.over the total linear growth period of the laminae.

rob the preceding growth studies I concluded'there arb three types

of laminde on a frond at the beginning of any measureqent period , '\ i i exceedirig 22 days. 54 I \ 1. $e lamina which has grown for part of the 22 days growth period and\ ,

------dill cease growth before 22 days. - - I / I + // - / 2. helaminae addeddwing the measurement period and will complete I I their growth before the end of the calculation period. 3. ,! The laminae that are formed less than 22 days from the termination

- of the calculation period and will not cease growth before the end

i >- ,/ of the calculation period. The following forhula includes formulae I 1 to calculate .the total area increkrit (A) of all 3 previous I' I' I j categories of:tlaminae : ,- I, I A = S ( (La. X 1.9) (La X .4) + Lc (364) i!,

/ Where S is the sum of laminae area increment for each blade position I from 1 thru 9'and 364 is the total area,incr&ent for a lamina over I I 2 ! i 22 days cm . La is the duration of lamina growth for a blade present at the beginning of the study period. Where Ba is the blade position relative to the apical scimitar,and

1 blade is formed every 2.5 days. Ib is the duration of .lamina

growth for a blade formed during the calculation period but without'

a complete growth peridd.

Where Bd is the blade position relative to the last blade with a L If complete growth period. &c is the number ofhminae growing for

22 days in the calculation period.

Where T is the calculation period.

Biomass Per Unit, Area of Lamina 2 The free weight of lamina tissue (gm/cm ) increased toward the

-9 basal region of the frond (Fig. 10). The mean fresh weight of sporophyll

tissue was significantly greatek than for all other laminae. The

*, variation and range of values were extreme for the sporophylls (Fig. 10).

The ,mean area of he first independent lamina obtained from tracings used L- ' for the calculation of lamina weight (N = 10) was 414 SD,+- 199 an . The . . .. . - mean area of all independent lamina (N = 45) on the collected fronds was a, 2 660 SD -+ 116 cm . --

The two types of -M. integrifolia encountered in the distributional - survey may be accounted for bwtendency of the plant to develop larger

laminae in sheltered areas (Pace, 1972). . The laminae reach a weight Figure Variation in' the fresh weight of' -M. intesrifolia z., laminae with their position on the frond

vertical lines range gm/cm,square

horizontal lines' mean gm/cm square

rectangle, vertical axis ' SD gm/m square

lamina position

apical

mid I < - Ap ica I Mid .Basal '?3porophyll,

991 , - r( rt BL'ADE POSITION which canhot be floated by the pneumatocysts an3 drag the frond downward.

The observations on phenology, also vertical and horizontal distr,ibution

are presented with the description of herbivore distributipn. The growth of -M. integrifolia laminae is a moving belt qf tissu"e as with Laminaria laminae Mann (1972b) . However, it is very different from

Laminaria because instead of a single lamina grawing continuously,-+ laminae / ,I i area grm'# is determinate, ceasing within approximately 20 days and frond

growth continues with a more recent lamina (more apical laminae). That

is, the whole frond acts as a belt of blades which are individually growing

for a limited period.

Variation in the growth rate of fronds in terms of elongation of the

t9 stipe and blade addition for a given frond size will be discussed in two

aspects relevant to the study period. First is the importance of trans-

location and the condition of other fronds on the plant. fl$ has been

- shown that old M. integrifolia fronds translocate nutritive material to - 1 ,+ young fronds less than a meter in length (mbban, pers. cornm.) . The loss Q of the primary apical scimitar appears to increase the transport of

- translocate to secondary fronds on the plant. Therefore, we could expect I significantly different growth rates for a given f-rond size depending on

the condition of its associated fronds. - 1 1

Secondly, within a given kelp bed there are physical gradienk which

may influence the growth rate of fronds. For example, depth has been I correlat-ed with the frond weight of -M. pyrifera (North, 1971).

b - In the case of M.- integrifolia this factor may be significant since some of the plantg in most -M. integrifolia beds are intertidal (Scagel, 1947). '. 6 The morphological variation,,of wave-sheltered and :wave-exposed..•’ronds *, suggests, that a wave-exposure gradient through a kelp bed may affect J growth- rates, in particular lamina width, (pace,. 1972). Lamina grawth measurements depended on following the movement of .. holes punched in the laminae., The holes were usually placed near the base -, of the laminae and I did not measure growth beyond this point except in 3 J / growth pattern studies. Grwth did occur beyond the base, however, the

error in the final calculation of area increment appeared to be redueed, i -because the first independent lamina was split from the apical scimitar due 1 to unpredictable environment&$.-factors such as wave action. As a result , .x. of these factors the size and- overall growth rate of the first independent . /' lamina was highly variable. Calculated from the movement pf holes the 2 total area' increment, was 364 SD -+ 167 cm . This value was well within

area increment measured from laminae tracing from the first independent

lamina to the most basal Jaminae. ... *' * The cessation of growth or growth at a low uniform rate in lamina area

was suggested by the relative siz~.sflaminae on the frond. Laminae I ,'

i' i' ' .z reached a maximum area new the mid region of the frond and frequently were e

"S smaller in the basal region,. This pattern was observed in M. Pyrifera _f I' - L fronds by Sargent and ~antki~(1952) . Aleem 619733 , following hole h b - movement to measure growth of -M. pyrifera found laminae ceased growth after * -4G- P 4 to 6 days, in which time they were approximately 2 mete- from the apical

scimitar. - Thickness was not included in these measurements but increasing * weight per unit area of lamina toward the base of the frond suggests the

rneris toderm 'is actively adding tissue after surf ace area growth ceases. . . .

4 -~n-M. integrifolia the weight of tissue per unit could be an important factor; irpKthe strength of the lamina and in the survival of laminae. / ,, , ', - ,' / ~~o~~"h~llshave a significantly higher weight per unit area than adjac nt

s, s, ? laminae and were okserved to pv~istlong after mor; apical laminae were -4 ,-- I 10st . ,The. mechanical strength of the' heavier spor2 phyll tissue could be a deterrent to herbivore damage and etosio'n . METHODS

A series of field studies w re canducted onfthe distribution of - 9. -T. pulligo in the southeast area of Barkley Sound, A number of problems were encountered in these surveys. Undenhter observations were often ** limited by poor visibility. The snail presented, probl&ns due to its

small size and,crygtic colouration. The high -relief of the substrate and ., %"' b the large undulating sui'face of M. integrifolia created prablems locating - I

the snail. . Q t -'

f I

1. ' ~eneralDistribution of -T. pulligo in Southeast Barkley Sound

Seven sites were selected wilh a Fnge of ivave exposure (Table 11,

Fig. 11). These sites were s 4eyed sing a compass transect perpen-

dicular to the shoreline. A 1 m quadrat was laid every other meter along

a weighted line. Plant cover, substrate type and Eerbivores within each

quadrat were assessed on each transect. The end of each transect was

determined by the lower limit of the sea urchin'~trongy1ocentrotus

franciscaims (A. Agassiz). The depth Was recoided with a calibrated, - diver's depth gauge to .25 m. All data were transmitted to a surface tape

recorder with a Sub-Com underwater cclmmunication system (Sub-:om System Ltd., -

North Vancouver, Canada). An additional two-sites were surveyed using

random quadrat placement. TABLE I1

- -- - d -- -* ---_ Location and Wave Exposure of Temporary Transects in the General Survey of 2. -Distribution -- shown on Figure Number 11 -. a,".

a b .d Chart Location Datg * ' Latitude ,Open Fetch Km . Expasure M. i . Number Longitude Angle Min . , Max Index Degrees .$ \

.' 1 Flemrning 11/3/73 48053 00 N 125' 13.7 2.6 M.S. c - I. 125'08 24 W

2 Scott's 21/3/73 48'50 06 N 175' un- 2.6 E - Bay 125'08 54 W limited /-

3 Kelp Bay 12/3/73 48'51 18 N 90' 16.1 4.8 M.S. + 125O06 30 W S. 4 N '. \ 4 ,..$' He4by I. 9/3/73 48'51 24 N 180' 16.9 1.6 M.E. + cn i-l 125'09 54 W 4

Swiss Boy 23/3/73 48'55 00 N 180' un- 1;2 E. 11. 125'07 48 W limited 4 *. ~rqppld'r 20/4/73 48'50 30 IN * 110' 16.1 2.9 M.S. Mouth 125'08 00 W S.

I Sanford I. 8/3/73 180' un- 1.2 M.E. 1imi ted

RO~SIslets 20/4/73 47 O 5.6 .5 S.

Blye Stone 8/10/72 , 180•‹ un- 2.6 , E. Pojnt limited

i Open Angle - angle through which waves can travel unrestricted - Fetch+- maximum distance for unrestricted wave travel M.S. - moqerately sheltered, M.E. - moderately exposed Macyo$ystj$i integrifolia I i.

rl Figure 11 Locations of study sites in Southeast Barkley

Sound, ~GcouverIsland

numerals * ' Temporary survey sites.' I letters permanent transect sites and the L detailed !study site ,- . BMS Barnfield Marine Station

scale 1 cm = 1.2 Jm . . ---, . From chart - 3637 Barkley ~~und

. impa ass variation 23 degrees 30 min East -2

seasonil is-tribution oi 2. pull* ma ~erHerbivores - - t

Permanent transects were con~truct~dat four sites chosen for their

diversity of exposure, diversity of kelp bed, substrate type and F - ./- herbivores (Table 111, Fig. 11). Transedts -Pw e set perpendicular to the shore line beginning at the edge of the intertidal zone (except at

and ending at least 5 m beyond the outer limit of -M.

A 1/8 inch plastic line was tied to 3/8 inch rock bolts

drivel/ into bedrock or boulders. The line was used as a quide only, and on eadh survey a plastic surveioi-s qhain (metric) was strung between the 2 pins. i fi 0.5 m quadrat was placed at 2 or 4 m intervals along the chain * and @.ant cover, substrate tyge and herbivore concentrations were recorded. \, ?. At scott's Bay the density of the kelp bed prevented the use of a quadrat. Instead, a line enco~ntermethod was used. The herbivores

J were counted on each plant that touched the line. Transect surveys all began in September 1972, bqut the Scott's Bay transect was abandoned in mid- winter, 1972, because large plants were drifting free in tangled mass-es ' , along the transect. The data for the wizard Islet transect were incomplete due to the difficulty of maintaining a transect line. The China Hat Pass and Kelp Bay transects were surveyed successfully each month from 1 . ~eptember19 i 2 to septemb& 1973 excepting December 1972 and August 1973.

During all'surveys qualitative observations were,made on the distrilmtion and behaviour of -T. pblligo? TABLE IIX

Location and Wave Exposure of Permanent Transects

and Detailed Study Site Shown on Figure 11 , Chart Open - Fetch Km Exposure -M. integrifolia Letter Location Longitude A& 1 e Min. Max. Index " Degrees a Kelp Bray M.E.

China Hat 4-jL M.S. Pass

Rosa Islet 4.0 M.S. Plateau .

\ Wizard Islet t

- Scott's a Bay

\'\\~ M.E. - moderately exposed;'. M.S. - moderately The 'population Structure of

In argas near the permanent transects, collect~onsof -T. pulligo

w,ere made from two, distinct regiqns. One collection of 20-50 9%- \ ' , * " k- individuals from ona'or beneath 5. integrifolia, and one collection from

4 the substrate outside the beds were made after each month's transect =? -2 'tr survey. Degenerat- of the kelp bed in the winter pr vented successive +,\ collektions from -M. integrifolia. At China Hat pass the sampling

procedure for substrate collecd&$ong.was changed from a subspate sqface F h :.-. .gs- '< ',,s * 8. c collection to a complete removal of the upper 5 cm of the subs&ate, -,-- i .I 2 - because I noticed individuals less than 10 mm basal diameter were absent - C in the previous samples.

The final collection at Kelp Bay wad- to distinguish the size of %? individuals upon the rocks and shell sand,wh*h had previously been grouped . - as a cobble collection. The basal diazt&r of each snail was mequred to -fl------d.- 0.1 mm with vernier calipers.

Motility I

In all motility experiments -T. pulligo was tagged by the following

method. A portion of the shell spire was scraped cleap of encrustation.

A drop of non-toxic epoxy (Sea Go-In Poxy Putty, Permalite Plastics,

Costa Mesa, Cal. , U .S .A.) was placed on the'klean' area and a piece of - : labeled plastic tape was pressed into the epoxy (Rosenthall, 1969) . Care

: was taken to prevent the loss of the label whil; the epoxy set. .The

specimens were held in running seawater prior to replacement in the field. Motility and ~ubstratiePreference of Tagged -T. pulligo .

The purpose of ;this experiment was to study. the movement and

substrate preference bf 2.. pulligo in the kelp bed.

Tegula pulligo Were collected from three distinct and adjacent areas:

shell sand, bedrock and on or beneath -M. integrifolia at the Ross Islets

kelp bed. Each of the 138 animals was coded for individual ide&i.Eication . . and its substrate oriyin, then the basal diameter was measured to 0.1 rnm.

Tfie collections from shell sand and -M. integrifolia were switched when

replaced in the fieldi and the bedrock collection was the control. Each * i -colle+on was deposited in a permanent 0.5 m quadrat. A search was made i

within a 15 m radius kor 0.5 hr at 3, 13, 30 and 48 days after replacement.

The&lB$ers within the' deposit quadrats, distance from point of replacement

Znd numbers of each type of substrate were noted using underwater writing

slates .

Motility of Tagged -T. 'pulligo on M:- integrifolia

An isolated plant at the end of-the Scott's Bay permanent transect was

- exaained for the ,~ftagged' and untagged individuals at 5, 10, 15 *: >- and 88 days after deposition.' - I --

Kelp Bay Infestation ~xperimedt / - This experiment tested the rate of recruitment of -T. pulligo to -M. integrifolia in areas devoid of -M. integrifolia. Two fronds 1.5 m long were attached to stones with rubber bands. One frond waslaced in an gs. area of cobble -Substrate adjacent to the permanen; transect at Kelp Bay. >+ - The second frond was set 15 m from the first frond at the seaward end' of '8%. . the transect: I 'counted the number of herbivores on the fronds and not&d .9.$ the grazing damage after 2 and 4 days in June, 1972.

* i - Motility as Related to Water Movement P

To determine if -T. pulligo mtility was affected by water movement