Stevenson: Natural History of Kelletia
Abstract
The predatory gastropod, Kelletia kelletii, was studied in the
lab and in the field to characterize its habitat characteristics,
distribution patterns, activity patterns, and escape responses. The
mean density of Kelletia was 0.32 m-2, and their depth range was
5.5 to 12 m. Snail sizes differed significantly between those found on
rock and on sand: the mean size of snails found on rock was 78.4
mm, while the mean size for snails found on sand was 92.9 mm.
Adult snails in the lab and the field bury themselves for up to 152
hours, punctuated with bursts of activity. There was no significant
relationship between the percent time buried, the length of the
buried period, the length of the active period, or the rate of
movement, and size of the snails. No clear relationship existed
between the activity pattern and foraging, and gut content analysis
was inconclusive. Kelletia captured and consumed Tegula or
Calliostoma ligatum in both the lab and the field. A large mating
aggregation was found during the study. Snails were significantly
larger within this aggregation. Kelletia exhibited no escape response
to three sea stars and a crab.
Stevenson: Natural History of Kelletia
Introduction
Kellet's whelk, Kelletia kelletii, is a large predatory
neogastropod found in the subtidal zone to depths of 70 m. It grows
up to 170mm in length and has a heavy, bulky, thick shell. It has a
long, extensible proboscis used for feeding, which can be extended up
to 3 times the length of its shell. The foot is very muscular, and is
colored yellow with white speckles and black lines around the edge
of the foot (Morris et. al., 1980).
Kelletia was, until 1980, primarily a southern California species.
In 1980, the first snails were discovered in the Monterey Bay area,
and have since grown in abundance and can commonly be found in
offshore reefs in the area (Herrlinger, 1981). Little is known of the
behavior and life history of Kelletia, and what little work has been
carried out has been performed in southern California. Its trophic
association with Pisaster giganteus has been studied (Rosenthal,
1971), as has its reproductive biology (Rosenthal, 1970).
This study examined the habitat of K. kelletii, its local
distribution, and its activity patterns in the lab and field to
determine if major differences exist between the expanding edge of
the species' range and the central portion of its range.
Materials and Methods
The study was carried out at the Hopkins Marine Station of
Stanford University in Pacific Grove, California during April and May
1994. Field studies were conducted in the Hopkins Marine Life
Refuge offshore from the station (Fig. 1).
Stevenson: Natural History of Kelletia
Population Studies
Random sampling was conducted to determine the population
density of Kelletia in the Hopkins Marine Life Refuge. Random
compass bearings and kick cycles (ranging from 5 to 50,
approximately 1 meter per kick) were used to determine sampling
locations. The type of substrate, depth, number, and size of the
Kelletia were recorded for each 5-m2 circular quadrat. Quadrat
counts were continued until the slope of mean versus number of
quadrats approached zero (21 quadrats).
Lab Activity Patterns
A tank measuring 230 cm x 110 cm x 40 cm (water level
maintained at 20 cm height) was used to track four Kelletia at a time
to observe activity patterns. Their activity periods, distances and
directions were recorded. Trial 1 was conducted for 65 hours, with
four snails with distinct markings placed in different locations in the
tank. A dead smelt was placed on the sand next to the inlet pipe
approximately 27 hours after the start of the observation period. At
the end of the observation period, the dead smelt was removed and
the tank flushed with fresh seawater before the Trial 2 was begun.
Trial 2 lasted for 216 hours. Four new snails were used and
were tagged with waterproof epoxy. The snails were placed next to
each other in the center of the tank. A dead smelt was added to the
tank next to the inlet pipe after 124 hours.
Trial 3 lasted 74 hours. In this case the dead smelt was in the
tank to begin with and remained in the tank for the duration of the
Stevenson: Natural History of Kelletia
observation period. Again, four new snails with distinct markings
were used and were placed in the center of the tank within 2 cm of
each other.
Field Activity Patterns
Fifteen Kelletia were collected from the field on May 6, 1994.
and were tagged with epoxy attached to their shells (Rosenthal,
1969). Numbers were etched into the epoxy to distinguish
individuals. Bright yellow nylon strings approximately 10 cm long
were attached in the epoxy tags to aid in relocation. These tagged
snails were then taken to Location 1 (Fig. 1) and released at
approximately 5:00 pm. The snails were then observed 18.5 hours
later in the same vicinity. Headings and distances moved from the
original drop point were measured with a compass and a tape
measure to the nearest cm.
A second group of twenty snails were collected and tagged
according to the procedure outlined above, with an additional mark
on the epoxy to distinguish the snails from the original tagged group.
The snails were kept overnight and released at Location 1 (Fig. 1) the
next morning. The snails were observed 1.5 and 4 hours later, and
then again 73 hours after release. As in the first tagged group,
headings and distances moved from the original drop point were
measured in a similar fashion.
Gut content analysis was performed on five snails: three
collected from the sand, and two collected from rocks, to determine a
relationship between activity patterns and foraging behavior. The
snails ranged from 85 mm to 95 mm in length.
Stevenson: Natural History of Kelletia
Feeding Studies
Six Kelletia were placed in a tank measuring 50 cm x 50 cm x
30 cm (water level at 28 cm) for five days to observe their feeding
behavior. For the first three days, 5 Tegula montereyi, 5 Tegula
pulligo, 5 Tegula brunnea, and 5 Calliostoma ligatum were placed in a
tank with the Kelletia. On the fourth day, all the Tegula and
Calliostoma were removed and replaced with 10 Tegula pulligo, 10
Tegula brunnea, and 5 Calliostoma ligatum. These were left for two
days. On the sixth day, all non-Kelletia snails were removed. A
second trial was run for two days with a new group of 5 Kelletia
offered 5 T. montereyi, 5 T. brunnea, and 5 T. pulligo. After two
days, all non-Kelletia snails were removed and small glass test tubes
containing invertebrates were placed on their sides in the tank. The
invertebrate specimens were collected from a vertical face of a
subtidal boulder in the Hopkins Marine Life Refuge, and consisted of
an oyster, a polychaete worm, a tunicate, a sponge, dead polychaete
worm parts, a dead sipunculid worm, a living sipunculid worm, and a
chiton.
In addition to lab observations, Kelletia were examined in the
field to determine whether they were feeding and, if possible,
identify their prey.
Mating Aggregation Observations
On May 17, 1994, a mating aggregation of Kelletia was
observed at Location 2 (Fig. 1). One week later the densities of snails
in the aggregation was measured with a 1/16 m2 quadrat, placed 7
Stevenson: Natural History of Kelletia
times at haphazardly selected points in the aggregation. The number
of snails within each quadrat was recorded, and 68 snails were
collected for size measurement.
Escape Response Studies
To assess whether habitat utilization may be influenced by
interactions with predators, Kelletia escape responses to the sea stars
Pycnopodia helianthoides, Pisaster brevispinus, and Pisaster
giganteus, and to the crab, Cancer antennarius were examined. P.
giganteus and Cancer occur primarily in rocky areas, while P.
brevispinus and Pycnopodia inhabit both rocky and sandy
substrates. One Pycnopodia, one P. giganteus, and two Kelletia were
placed in a fresh circulating seawater tank measuring 90cm x 90cm x
60cm (water level maintained at 25cm height). One Kelletia was
placed with two Cancer in a separate tank with the same
measurements. The snails were allowed to move freely in the tank
along with the two sea stars and the crab. Observations were
recorded for five days in each of the tanks. The escape response to
P. giganteus was studied in the field during two separate SCUBA
dives, in which the tube feet of P. giganteus were touched to the foot
of Kelletia.
Results
Population Studies
The average density of Kelletia at random sampling locations
within the Hopkins Marine Life Refuge was 1.62 per 5 m2 (SD=2.29,
Stevenson: Natural History of Kelletia
n=21), or 0.32 m-2. The depths at which the snails were found
ranged from 5.5 m to 12 m, with the majority of snails deeper than
7.5 m.
The snails were found on both rocks and sand. Rock locations
included rocks ranging in size from small fist-sized rocks to large
boulders, and sand beds included bare sand, mats of the tubiculous
polychaete, Diopatra ornata, and sand channels between rock
outcroppings. The mean length of snails found on the sand was 92.9
mm (SD=12.0, n=15), while the mean for rock locations was 78.4 mm
(SD=14.8, n=26, Fig. 2). The size difference between the two
populations was significant (t-test with unequal variances; pæ0.01).
Lab Activity Patterns
The snails in the lab characteristically buried themselves for
extended periods of time, punctuated with bursts of activity in which
the snails would move around the tank (Fig. 3). The snails ranged in
size from 79 mm to 97 mm, and all snails buried themselves
completely in the substrate at least once during the observation
periods. When burying, the front edge of the foot dug into the sand
and pulled sand up over the front edge of the foot. The siphonal
canal was pulled completely under the surface of the substrate, and
the snail then rocked the shell in a spiraling motion until burial was
complete. Once burrowing began, all snails were buried within 15
minutes. The siphon was extended out of the sand only once out of
25 observed burial events.
Activity patterns varied substantially among individual snails.
Several remained buried for a very long time and became active only
Stevenson: Natural History of Kelletia
once or twice during the trial (Snail 10, Fig. 3c). Others buried
themselves up to 5 times with intervening active periods of varying
lengths (Snail 7, Fig. 3b). No diurnal pattern of activity was
observed. On one occasion snail 9 followed the path of snail 11 over
a distance of 195 cm, and snail 10 followed the path of snail 12 over
a distance of 50 cm. In both instances, the 2 snails burrowed back
into the sand adjacent to each other.
The length and interval of buried and active periods were
determined for each snail in each of the three sessions (Fig. 3). The
median percent of time spent buried for all the snails was 84%
(SD=21; Range: 34%-97%). The median length of buried periods was
28.6 hours (SD=40.1; Range: 8-152 hours). The median length of
active periods in all three trials was 6 hours (SD=4.3; Range: 2-16
hours). The median movement rate during active periods in the lab
was 16.5 cm per hour (mean-25.1 cm/hr; SD=21; Range: 21-79 cm
per hour). There was no significant correlation between snail sizes
and percent time buried, length of buried period, length of active
period, or movement rate (p»0.16 for all regressions; Figs. 4-7).
Field Activity Patterns
Eight of the fifteen snails from the first tag-and-release trial
were found 18.5 hours later. Of these, 5 snails were buried in the
sand within 1 m of the release point. The other 3 snails had moved
between 622 and 1087 cm and still appeared to be moving. All
three snails were still on sand and had moved in the same direction.
In the second group, 19 of the 20 snails were found within 1.5
hours, 16 were found after 4 hours, and 12 relocated after 73 hours.
Stevenson: Natural History of Kelletia
Nine snails were found either half-buried or completely buried at the
first two observation times, while 6 snails were found buried in
similar positions after 73 hours. Three of the 12 snails recovered
after 73 hours had moved onto rocks from the sand, one of which
was associated with a P. giganteus. Neither the snail nor the sea star
were feeding.
The 3 snails from the first tagged group and the 8 snails from
the second tagged group that exhibited marked movement were used
to calculate the field movement rate. The median movement rate in
the field was 40 cm per hour (SD=18.1; Range: 11-87 cm per hour).
This rate was not significantly different from laboratory estimates (t-
test assuming unequal variances; p=0.31).
Approximately two weeks after release, 3 snails from the first
group of tagged snails were observed at least 40 meters away from
the original release point (Location 1, Fig. 1). These three snails were
at a mating aggregation (Location 2, Fig. 1).
Gut content analysis and feeding
Only one of five snails had food in its gut. The contents could
not be identified. This snail was collected from the sand but was not
buried. The other four snails, two collected from the sand and two
from the rock, all had empty guts. The gut content analysis was thus
inconclusive. However, four of the five snails were reproductively
ripe. The fifth snail lacked a gonad and the inner surface of the shell
was encrusted in the area where the gonad would have been.
During the activity studies, Kelletia fed on the fish placed in the
tank on two occasions: one snail sat on the fish for a period of hours,
Stevenson: Natural History of Kelletia
then moved off and buried itself. In the other case, evidence of
rasping was found on the underside of the fish, indicating that a
buried snail had fed on it from below, or a snail had extended its
proboscis underneath the fish. In the first trial, three of the four
snails came out of the substrate within 2 hours after introduction of
the fish. The snails in the second tank did not react as quickly,
though, and it was at least 21 hours before any snail came out of the
substrate. In Trial 3, snails 9 and 11 (Fig. 3c) passed within 5 cm of
the fish, but did not come in contact or stop to feed.
Two T. brunnea, 2 T. pulligo, 3 T. montereyi, and 2 Calliostoma
ligatum were consumed during both lab feeding trials. During
capture, the Kelletia encountered the Tegula from different directions
each time. Kelletia then forced its foot under the shell rim of the
prey and gradually wrapped its foot around the underside of the
Tegula. During feeding itself, the Kelletia rested on the back or side
of its shell on the bottom of the tank. Complete consumption of prey
lasted at least 6 hours. In two of the three instances of predation on
T. montereyi, the head and foot were not consumed. During the
second feeding trial using a new group of Kelletia (n=6), one T.
montereyi was consumed completely.
When offered other invertebrates, Kelletia only consumed the
live sipunculid worm after it had crawled out of the test tube. In no
case was a Kelletia observed inserting its proboscis into the test
tubes to reach the invertebrate inside.
In the field, Kelletia were found feeding on Tegula brunnea on
three separate occasions. In one instance, a Kelletia was found in a
Diopatra mat with its proboscis extended at least 3 times the snail’s
10
Stevenson: Natural History of Kelletia
length, presumably feeding. The prey, however, could not be
determined.
Mating Aggregation Observations
The density of snails in the mating aggregation (Location 2, Fig.
1) was 260 snails m-2. The mean size of the snails observed in the
aggregation was 89.9 mm (SD=8.3; n=68; Range: 74-115 mm; Fig. 8).
The mean size of Kelletia outside the aggregation (on sand and rock)
was 84.4 mm (n=68; SD=15.0; Range: 36-122). The difference in snail
sizes between the two populations was significant (t-test with
unequal variances; pæ0.01).
Escape Response Studies
Kelletia exhibited no escape response to Pycnopodia or P.
brevispinus in the laboratory. On three occasions Pycnopodia
climbed over the snail, its tube feet making contact with the snail's
foot; in each instance, the snail showed no reaction. On one other
occasion, the P. brevispinus passed one arm over a Kelletia, also
coming in contact with the snail’s foot. Again, the snail showed no
escape response to the sea star. In the field, P. giganteus was placed
in contact with a snail on two occasions. The snails showed no
response either time. In addition, one tagged Kelletia was found
underneath a P. giganteus, although the sea star was not feeding on
it. The snail was not obviously trying to escape.
Kelletia placed in the tank with the crab Cancer antennarius
also did not exhibit escape responses. The Cancer succeeded in
breaking off a few shards from the lip of the shell, but never actually
11
Stevenson: Natural History of Kelletia
ate the snail. While being manipulated by the Cancer, the snail did
withdraw into its shell and remained there for some time after
manipulation.
Discussion
The depth distribution of Kelletia kelletii in southern California
ranged from 2 to 40 m (Rosenthal, 1971). This contrasts with
Monterey, where 5.5 m was the shallowest depth at which K. kelletii
was found. Searches at shallower depths yielded no Kelletia. Further
detailed examination of the subtidal zone in the Hopkins Marine Life
Refuge may be necessary to determine the validity of the observed
difference in the upper depth limits. Areas outside the kelp bed
deeper than 12 m were not sampled, so a comparison between the
deeper limits is not possible at this time.
The large standard deviation associated with the mean
density of snails indicates that Kelletia has an aggregated distribution
throughout the kelp forest. Densities of K. kelletii in two southern
California sites were 1.82 m-2 and 0.73 m-2 (Rosenthal,1971),
compared to the 0.32 m-2 observed in the kelp bed in Monterey
This could be related to the recent range extension of K. kelletii into
the area, and the local population has not attained the densities
observed in southern California. Since my study was conducted
during Kelletia’s reproductive season, another possibility is that
many snails were concentrated at the mating aggregation, artificially
decreasing the density estimates. The burial behavior of the snail
may also have lowered the estimated density, since it was not known
at the time of field sampling that adult snails bury themselves.
12
Stevenson: Natural History of Kelletia
Further sampling including inspections of sand patches for buried K.
kelletii are necessary to determine the percent of the population
buried at any given time.
No snails smaller than 35 mm were found. In southern
California, juveniles as small as 18 mm were found (Rosenthal, 1971)
Further investigation is required to determine if juvenile snails have
a different distribution than adults in Monterey.
The significant difference in snail sizes on rock and on sand
could indicate a change that favors moving from the rock to the sand
as they grow older. The cues for such a shift are unknown, although
one possibility could be a change in diet. It is also possible that,
since Kelletia are quite mobile snails, the observed differences in
snail sizes between sand and rock habitats are coincidental. Further
sampling and larger sample sizes could clarify this issue.
Lab and Field Activity Patterns
Only Kelletia smaller than 40 mm in length bury themselves in
the substrate in southern California (Rosenthal, 1971). In Monterey
Bay, adult snails (79-97 mm) buried themselves both in the lab and
in the field. The reason for this difference is not known.
Activity patterns may be associated with foraging behavior.
Due to the large proportion of empty stomachs, gut studies did not
reveal whether Kelletia forage while buried or while active.
However, several indirect lines of evidence suggest foraging occurs
during active periods rather than when buried. The Kelletia fed on
prey that they would only encounter while active, namely the
Tegula. In addition, when food was added to the the activity pattern
13
Stevenson: Natural History of Kelletia
tank in Trial 1, three of the four snails emerged within 2 hours and
moved around on the sand, rather than burrowing toward the food.
Possession of such a long, extensible proboscis would allow Kelletia to
feed on buried prey without expending the energy required to
burrow. The snail observed in Diopatra with its proboscis extended
was feeding in this manner. The snail in Trial 2 may have done
likewise to feed on the fish from below. Finally, snails were
stationary while buried in the tanks, suggesting they were not
actively seeking food.
Why the burial occurs is unclear. Burial may be a defense
against predation. Juvenile Kelletia bury themselves to avoid contact
with P. giganteus, although they do not bury in direct response to
contact with the sea star (Rosenthal, 1971). The decreasing trends of
percent time buried and average length of burial interval with
increasing size (Figs. 4, 5) may also support a defensive function for
burial, since larger individuals are often less susceptible to predation
(Paine, 1976). Further sampling is required to confirm these
observed trends.
Alternatively, burial may be unrelated to predation. Snails
buried themselves in the complete absence of predators and showed
no escape responses to any of the predators tested. Lack of an
escape response is typical of southern California individuals as well
(Rosenthal, 1971). Although P. giganteus has been observed to eat
Kelletia, the lack of an escape response is not surprising since a
trophic association (i.e. communal feeding on the same prey item)
between these two species has been described (Rosenthal, 1971)
Kelletia associate with two other sea stars, Pisaster brevispinus and
14
Stevenson: Natural History of Kelletia
Dermasterias imbricata (Rosenthal, 1971). It is possible that, for
similar reasons, the snail does not exhibit an escape response to P.
brevispinus or Pycnopodia helianthoides, although no association
between Pycnopodia and Kelletia has been reported. In addition, the
shell is quite massive in the larger adults, and makes it difficult for
Cancer to break open the shell in order to consume the snail.
The burial period may also be a period of inactivity after
foraging since little or no movement was observed while the snails
were buried. A study conducted on P. giganteus indicates a similar
pattern of inactivity after feeding (Harrold, 1981).
Activity patterns may also be related to the reproductive cycle
of the snail. The active periods of snails in the lab were
characterized mainly by movement in straight lines as indicated by
diatom film trails, covering large distances until an obstacle was
encountered (such as a tank wall). This movement could be a search
for unknown cues indicating the mating aggregation. The snails that
followed each other in Trial 3 along very similar trails in the activity
pattern tanks indicate the snails may be responding to a mating cue.
The cue may be in the mucus secreted by the snails; Rosenthal
(1970) speculates that this may be the case as well. Future
characterization of the mucus would determine the validity of this
idea.
There may also be a behavioral hierarchy of activity and
foraging, depending on the reproductive condition. During non¬
mating times of the year, activity patterns of the snail may be
determined by foraging needs. Once mating cues have occurred, the
activity pattern may be governed mainly by searching for mates.
15
Stevenson: Natural History of Kelletia
During this time, feeding may become secondary. Two lines of
indirect evidence support this idea. The four snails with empty
guts
had very well-developed gonads and were active (rather than
buried) when collected. In addition, in the lab five Kelletia with
Tegula available for consumption spent all their time mating and
laying eggs, suggesting that mating had taken a priority over feeding.
Observations at non-mating times of the year would clarify the
possibility of such a hierarchy of behavior.
Mating Aggregation Observations
The larger mean size of snails within the aggregation than
outside the aggregation indicates that only sexually mature
(represented by larger) individuals are present in the mating
aggregation. No snail inside the aggregation was smaller than 70 mm
(Fig. 8). This can be approximated as the sexual maturity threshold
for K. kelletii. This data is roughly consistent with data from
southern California, which show the smallest snail in a mating
aggregation to be 62 mm in length (Rosenthal, 1970).
Whatever cues may be in effect for the mating aggregation
work over a large distance and seem fairly specific considering three
snails from the original tagged group were observed withing meters
of each other. However, the cues remain undescribed and identifying
them would be a very interesting avenue of research. The activity
patterns of all the snails at non-mating times of the year would be
very informative as well.
16
Stevenson: Natural History of Kelletia
Acknowledgements
I would like to extend a heartfelt thanks to Dr. Jim Watanabe of
Hopkins Marine Station for the invaluable assistance provided,
without which this project would have been completely
unmanageable. Advice on subtidal methods and help in improving
this paper are greatly appreciated. Thanks also to Gary Villa of
Powers Lab at the Hopkins Marine Station for allowing me to
convince him to spend more time underwater than is probably
healthy for a human being. Finally, I would like to thank all the
people at the Marine Station who made my three month stay there
one of the most memorable events of my life.
Stevenson: Natural History of Kelletia
Literature Cited
Harrold, C. 1981. Feeding ecology of the asteroid Pisaster giganteus in
a kelp forest system: Prey selection, predator-prey interactions,
and energetics. Ph. D. dissertation, University of California
Santa Cruz.
Herrlinger, T. J. 1981. Range extension of Kelletia kelletii. The Veliger
24 (1): 78.
Morris, R. H., Abbott, D. P., Haderlie, E. C. (1980). Intertidal
Invertebrates of California. Stanford University: Stanford
University Press.
Paine, R. T. 1976. Size-limited predation: an observational and
experimental approach with the Mytilus-Pisaster interaction.
Ecology 57: 858-873.
Rosenthal, R. J. 1969. A method of tagging mollusks underwater. The
Veliger 11 (3): 288-289.
Rosenthal, R. J. 1970. Observations on the reproductive biology of the
Kellet's whelk, Kelletia kelletii (Gastropoda: Neptuneidae). The
Veliger 12: 319-324.
Rosenthal, R. J. 1971. Trophic interaction between the sea star
Pisaster giganteus and the gastropod Kelletia kelletii. Fishery
Bulletin 69 (3): 669-679.
18
Stevenson: Natural History of Kelletia
Figure Legends
Fig. 1: Map of the Kelp Forest and the Hopkins Marine Station
of Stanford University in Pacific Grove, California. Location
indicates the drop site for tagged snails, and Location 2 indicates the
mating aggregation discovered on May 17.
Fig. 2: Frequency histogram of snail size of K. kelletii found
outside of the aggregation; on rock and on sand.
Fig. 3: Graphs showing the burial intervals for three trials of
observations of K. kelletii in the laboratory. 3a shows Trial 1 lasting
65 hours, 3b shows Trial 2 lasting 216 hours, and 3c shows Trial 3
lasting 74 hours. Note the scales are different between 3a & 3c and
3b. White rectangular boxes indicate burial periods with length in
hours written in; plain horizontal bars indicate activity periods. The
shaded vertical bars indicate periods of no observations.
Fig. 4: Snail size versus percent time the snail spent buried,
with the fitted regression line and regession equation displayed.
Correlation is insignificant with a p value 50.05
Fig. 5: Snail size versus average length of burial period in
hours with the fitted regression.
Fig. 6: Snail size versus average length of active period in
hours with fitted regression.
19
Stevenson: Natural History of Kelletia
Fig. 7: Snail size versus average rate of movement in
centimeters per hour with fitted regression.
Fig. 8: Frequency histogram of size of snails found in mating
aggregation.
191







2



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3

0
14
Stevenson: Natural History of Kelletia
Fig. 2



o
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Size (mm)
22
Fig. 3a

Snail 1
28.6
Snail 2
28.6
Snail 3
35.35
Snail 4 -
22.225
Fig. 3b
L

Snail 5 -
71.5


Snail 6 —
2
1
L
51.5
Snail 7
1

Snail 8 -


Fig. 30

Snail 9
Snail 10

Snail 11—
Snail 12-

Stevenson: Natural History of Kelletia
Smelt Added

29.7
10
hours
23.3


78.5


151
33.25
30 hours


1
70.5



22.25
152.25

5

68
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23
1 —
0.9
0.8
0.7
9 0.6
- 0.5
2 0.4
0.3
0.2
0.1
75
Fig. 4
85
Snail Size (mm)
24
Stevenson: Natural History of Kelletia
%time buried
f (x) = -O.01x
+1.66
100
100
90
80
70
E 60
50
40
k 30
20
10
75
80
Fig. 5
85
90
Snail Size (mm)
25
Stevenson: Natural History of Kelletia

Avg. Burial Interval
f (x) = -1.96x +
220.06
100
14
12
10
75
80
Fig. 6
85
Snail Size (mm)
26
Stevenson: Natural History of Kelletia
Avg. Active
Interval
f (x) = 0.24x
14.48
95
100
80
70
60
50
§ 40
90
20
10
75
80
Fig. 7
85
90
Snail Size (mm)
Stevenson: Natural History of Kelletia
E
Avg. Moyt. Rate
f (x) = -O.95X +
116.64
95
100
16
12
Stevenson: Natural History of Kelletia
Fig. 8
HE
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8 -
Size (mm)
28