waders and their estuarine food supplies - Vlaams Instituut voor de ...

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$Wetenschap - \Nijverheid- Handel$

Fig. 2. AFDW ol the shell as a function ol size in Cerastoderma in = 1351). Macoma m = 703), Mya (n = 308) and Scrobicularia In = 158). The allonieinc functions refer lo bivalves < 20 nun The o.ikT.iiions aie high: r > 0.99, except lor Scrobicularia ir = 0.98). Despite this, the relationships appear lo deviate Irom linearity since Ihev are concave. because they stored the animals in running sea water at a temperature of 5 to 10 °C. Analysis The mean AFDW was determined for each mm size class on each sampling date. The regressions of ln( weight) on ln(size) were calculated for each sampling date (Table 3). The average number of animals sampled per size class varied between 5 in Mya and 43 in Macoma. The variation in AFDW within each mm-class determined the number of specimens needed to reach a 95% probability thai ihe standard error lay within 59 of the mean (Table 4). This variation was very small in Cerasioderma. so only 3 specimens were needed. But in the more variable Scrobicularia, the sample si/e must Iv six times larger, which is one of the reasons of ihe relatively poor correlation in the allometric equations in this species (Table 3). SEASONAL VARIATION IN BODY WEIGHT OF BIVALVES » Tahle 3. Overview of the data eollecled on the relation between Int AFDW) and In(lcngth): number of regression analyses performed (formulaeI. Ihe average correlation (rl. Ihe average number of min classes used IIII. the average number ol specimens weighed IVI and the avenge range (mm I over which the regressions were calculated. species formulae r n jr range Mm limn it,: .9915 12.7 549 7-21 Scrobicularia 183 .9464 S 1 137 28-42 Mya 228 .9900 I4.u 68 17-67 Cerastoderma 139 .9846 10.7 224 0.29 94- 70 C. edule i i i J F M A M J J A S O N D Fig. 3. Seasonal variation in ash contenl (± SE) of bivalves < 11 mm. including the shell. One-way analyses ol variance show that season has j highly significanl effect on Ihe ash comenl: Macoma iR- = 0.28, p < 0.001. n = 1205). Scnsbicularia (ft? = 0.74. p < 0.02. n = 18). Mya (R-" = 0.07. p < 0.001. n = 170) and Cerastoderma i R- = 0.26. p < 0.001. n = 4211.
SEASONAL VARIATION IN BODY WEIGHT OF BIVALVES Table 4. Variation in AFDW of three bivalve specie- when all specimens were weighed and separately cremated: month: month of sampling. n: number of mm-classes: \: number ot specimens; RSI): standard deviation as percentage oi the average weight ± SE; x needed: sample size in order lo reach a SE which is 5'i of the mean. ./,, ;• . USD • tuuded Macoma Scrobicularia Cerastoderma J F M A M J J A S O N D Fig. 4. Seasonal vanalion in ash conlenl (± SE) of the soft ptlts oi bivalves > 11 mm. Oneway analyses of variance show thai season has a highly significant effect on the ash content: Macoma (R* = 0.05. p < 0.001. n = 44601. Scrobicularia (R- = 0.12. 01, n = 6970), Mya
Page 1 and 2: WADERS AND THEIR ESTUARINE FOOD SUP
Page 3 and 4: plia^ohi. WADERS AND THEIR ESTUARI
Page 5 and 6: Waders and their estuarine food sup
Page 7 and 8: WADERS AND THEIR ESTUARINE FOOD SUP
Page 10 and 11: figuren: Dick Visser omslagfoto: Ja
Page 12 and 13: 15 Versatility of male curlews (Num
Page 15 and 16: That science is making progress, ma
Page 17 and 18: INTRODUCTION The remnants of brushw
Page 19 and 20: When hcnlhic bivalves extend llien
Page 21 and 22: the burrow depths and on the fracti
Page 23 and 24: INTRODUCTION Ms,i invest 409 of (he
Page 25 and 26: able lo sw itch 10 oiher prey which
Page 27 and 28: Long-term, broadly-based research c
Page 29 and 30: Chapter 1 SEASONAL VARIATION IN BOD
Page 31 and 32: SEASONAL VARIATION IN BODY WEIGHT O
Page 33 and 34: Tahle 1 Weight loss ('•- ± SE) m
Page 35: SEASONAL VARIATION IN BODY WEIGHT O
Page 39 and 40: i 60 50 40 30 20 10 0 • INFESTED
Page 41 and 42: 240- SEASONAL VARIATION IN BODY WEI
Page 43 and 44: 20 10 0 -10 -20h 2 3 4 5 6 7 8 9 se
Page 45 and 46: a E 400 - S. plana 35 mm 320 240 16
Page 47 and 48: SEASONAL VARIATION IN BODY WEIGHT O
Page 49 and 50: Chapter 2 HOW THE FOOD SUPPLY HARVE
Page 51 and 52: FOOD SUPPLY HARVESTABLE BY WADERS H
Page 53 and 54: Methods The study sites were situat
Page 55 and 56: less than that of bivalves, partly
Page 57 and 58: I Fig. 3). Peak condition was reach
Page 59 and 60: total biomass since most of those t
Page 61 and 62: on the basis of the preceding and t
Page 63 and 64: However, for obvious reasons, we ma
Page 65 and 66: prey. A decrease in the prey densit
Page 67 and 68: Tahle 2. The intake rate ol < lyste
Page 69 and 70: * ' % -. . ; a X - . - * • ^ •
Page 71 and 72: (Zwarts & Wanink 1989). In quiet we
Page 73 and 74: general law relating handling time
Page 75 and 76: nearly twice as much time (0.79 s).
Page 77 and 78: 4 5 6 7 8 9 size class of Corophium
Page 79 and 80: and annually. Second, the lower siz
Page 81 and 82: Prey switching Waders feeding on ti
Page 83 and 84: autumn and spring, and the contrary
Page 85 and 86: where they switch to surface-living
Page 87 and 88:
Chapter 3 BURYING DEPTH OF THE BENT
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DEPTH AND SIPHON CROPPING IN SCROBI
Page 91 and 92:
I DEPTH AND SIPHON CROPPING IN SCRO
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DEPTH AND SIPHON CROPPING IN SCROBI
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Table 3. Three-Way analysis Of vari
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Chapter 4 SIPHON SIZE AND BURYING D
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15 20 size (mm) Fig. 3. Cerasioderm
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10 size (mm) SIPHON SIZE AND DEPTH
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o, 7 01 5 | * CL 5- SIPHON SIZE AND
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4 Q) Si •a a. 16- 20- A predator:
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prey risk for an animal al a depth
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Table 6. Size al which there is a m
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* ' 1 /-/ "».-^*«C
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face and so expose themselves to a
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surface in die containers was varie
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50 OOF 310.00 I 5.00 ^ 1.00 3=" 0.5
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Tahle 1. Macoma and Scrobicularia.
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siphon would not have to reach the
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known siphon weight and burying dep
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ACCESSIBLE PREY ARE OFTEN IN POOR C
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1 2 3 4 burying depth (cm) Kin. I.
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I—1 • • : : : : ! - ! -|-r 0
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Chapter 7 DOES AN OPTIMALLY FORAGIN
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OPTIMAL FORAGING AND THE FUNCTIONAL
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100 200 300 prey density (n-m-2) Fi
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Table I. Results of five one way an
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Table 2. Results of eight iwo-wav a
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prey density II III Fig. 12. Freque
Page 147 and 148:
Page 149:
PREY SIZE SELECTION AND INTAKE RATE
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Predicted 'passive size selection'
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lig. 2. Larger Mussels are less ava
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Fig. 5. Scrobicularia plana. Size c
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and maiiv are too thick-shelled to
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The measurements of handling time i
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1 2 3 4 5 6 7 probing depth (cm PRE
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valves may vary by a factor of two
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optimal foraging model, the minimum
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their gut is full? Do they reduce t
Page 171 and 172:
PREY PROFITABILITY AND INTAKE RATE
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catchers to take only certain prey
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licult error of estimate arose if p
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Counts of feeding and non-feeding b
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20 30 40 50 shell length (mm) PREY
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Nereis Arenicola tipuia earthwo'm M
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take rate. We might therefore expec
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prey species, using parallel slopes
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5.0 4.0 1-3.0 a & • % * • * •
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time during the feeding period. As
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winter. Similarly, handling time in
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5.0 - f-4.0 S 3.0 in I 20 a 2 a | 1
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situation arrived in the western pa
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• ' • 14 PREY PROFITABILITY AND
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Notes lo appendix: PREY PROFITABILI
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Chapter 10 WHY OYSTERCATCHERS HAEMA
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2 4 6 8 10 time on feeding area (h)
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80- 60- o 80 60- 40- 20- INTAKE RAT
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est of bod\ behind: an estimated 22
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INTAKE RATE AND PROCESSING RATE IN
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Wanink 1993). The energy content of
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(7) Age All studies dealt with adul
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irds over long periods. As an examp
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Discussion There is no difference i
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comparison between the weight of ih
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. 1', L ! •
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Introduction PREDICTING SEASONAL AN
Page 232 and 233:
PREDICTING SEASONAL AND ANNUAL FLUC
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Page 236 and 237:
Page 238 and 239:
Page 240 and 241:
1000 r 1 II" 1 - r^Jan'80 PREDICTIN
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Page 244 and 245:
Page 246 and 247:
Page 248 and 249:
Page 250 and 251:
Page 252 and 253:
IOO BO 60 40 20 0 PREDICTING SEASON
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WHY KNOT TAKE MEDIUM-SIZED MACOMA W
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in Zwarts & Esselink 1989). The len
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shell length (mm) FIR. 3. Peringia.
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fused, specimens larger than this w
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50 100- s s I — f = S. plana, n=2
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area is twice as large as the touch
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10 15 lower size threshold (mm) Fig
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lime (Hughes 1979). This would furt
Page 281 and 282:
WHY KNOT TAKE MEDIUM-SIZED MACOMA T
Page 283 and 284:
Chapter 13 ANNUAL AND SEASONAL VARI
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VARIATION IN FOOD SUPPLY OF KNOT AN
Page 287 and 288:
Two sites (N and M in Fig. 2) were
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20 30 VARIATION IN FOOD SUPPLY OF K
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20 l i r'l ' i •o j^y^T n ^ ' " ^
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July ' Aug ' Sept Fig. 9. Proportio
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available. There must, however, be
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Chapter 14 SEASONAL TREND IN BURROW
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BURROWING AND FEEDING IN NEREIS SEA
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Table 2. Results of a 2-way analysi
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June 1981 June 1982 is * N.MUD •
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8 10 I 12 JZ 5. -g 1*» •e o i 16
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6 - n=!080 5 • g 4 CP > i 3 CO CD
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1985) and Curlew (/wails ,v, Lsseli
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Chapter 15 VERSATILITY OF MALE CURL
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Smid! 1951. Muus 1967, Wolff 1973,
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0.6 0.8 1.0 1.2 1.4 1.6 jaw lengih
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Na oi both Nrieck Fig. 7. Numenius
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6 8 10 12 14 16 18 worm length (cm)
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too (Fig. 11 A). Indeed, the averag
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VERSATILITY OF CURLEWS FEEDING ON N
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total time spent al the surface. Th
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2 4 . • 2.2 • 30 .-.2.0 to Q. 1
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PREY DEPLETION BY OYSTERCATCHER AND
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the rule: the observed lower limit
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to locate the clams after they had
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Curlew, by bury ing some hundreds o
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PREY DEPLETION BY OYSTERCATCHER AND
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SAMENVATTING 345
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Voorgeschiedenis In 1960 verscheen
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maken. Als gebied A een grotere voe
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omdat ze nog vrijwel niets wegen. l
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kunnen opzuigen. of diep leven en z
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van de uitgerekte sifo over het wad
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het toen niet gemakkelijk hebben ge
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doende nonnetjes van 10 tot 15 mm l
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aangevoerde voedsel en de wulp past
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zijn dan twee jaar en wulpen geen s
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was dan ook dank/ij de inzet van al
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REFERENCES 367
Page 365 and 366:
Allen RL. 1983. Feeding behaviour o
Page 367 and 368:
BreyT. 1989. Der Einfluss physikali
Page 369 and 370:
latie tol chironoiiiiilen en de wai
Page 371 and 372:
huch der Vogel Milteleuropas, Band
Page 373 and 374:
llolmann II. & H. Huerschelmann 196
Page 375 and 376:
l-cndrem D.W. 1984. Flocking, feedi
Page 377 and 378:
Pekkarinen M. 1984. Regeneration of
Page 379 and 380:
lion of Mussels Mytilus edulis hy O
Page 381 and 382:
lulal Dal esiuanes: a comparison of
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