a review of methods used for estimating gut evacuation rates
Transcript of a review of methods used for estimating gut evacuation rates
A REVIEW OF METHODS USED FOR ESTIMATING GUT EVACUATION
RATES AND CALCULATING DAILY RATION FOR FISH
Richard W. Langton Northeast Fisheries Center Woods Hole Laboratory Woods Hole, Massachusetts 02543 Laboratory Reference No. 77- 07 May 1977
INTRODUCTION
In the past, little effort has been made to combine digestion rate
data and food habits studies to determine the food.turnover for a given
population of fish. Ten years ago Windell (1967) reviewed the status of
digestion studies in fish and suggested that, at that time, one of the
most outstanding needs in future research was to ~stimate food consumption
in terms of the daily ration. Since the amount of digestible food
consumed largely determines the growth and production rates in any
population, information on the daily ration is needed in order to model
natural populations or develop controlled ecosystems for fish culture.
In recent years more emphasis has been placed on combining laboratory
and field studies to determine digestion rates in fish experiencing near
natural conditions. Most of these studies have recently been reviewed by
either Kapoor et ale (1975) and/or Grove et ale (1977). The purpose of
this review is to update these previous articles where necessary and to
identify the factors which must be considered in attempting to convert
the food habits data collected by the Northeast Fisheries Center, Woods
Hole Laboratory, into estimates of the daily ration for selected Northwest
Atlantic fish species.
The review is divided into four general sections. The first
describes the methods used in determining digestion or gut evacuation
rates. It should be mentioned here that digestion rates should more
accurately be termed evacuation rates. Most of the experiments described
herein have only determined the rate of removal of food from the stomach or
gut without any reference to abscirption of the food or undigestible
materials. The fish literature uses the words digestion and·evacuation
interchangeably and no attempt has been made in this paper to distinguish
between terms. The second section of the review considers factors
influencing gut evacuation times and is. follow~d by a brief discussion
of factors which generally affect the collection of food habits data.
The final section of the paper considers the various models for determining
gut evacuation rates and the methods which have been proposed in
calculating daily rations.
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METHODS FOR STUDYING GUT EVACUATION RATES
The methods used to study gut evacuation rates in fishes have combined
a variety of laboratory and field techniques. They can, however, be broken
down into at least three general categories as out"ined by Kapoor et ale (1975).
Recovery of Stomach Contents
Fi sh have been fed known quant it i es of food and at predetermi ned i nterva 1 s
the amount of food remaining in the stomach was established by sacrificing the
, fish or pumping out the stomach. Markus (1932) followed digestion in largemouth
bass, Huro floridana (Micropterus salmoides), af~er force feeding with minnows,
by injecting a nitrous acid solution to induce' the fish to regurgitate their
stomach contents. Bajkov (1935) recovered and measured volumetrically the
partially digested food from the stomach of whitefish, Coregonus clupeaformis,
at different times after capture. Unfortunately, Bajkov's work is somewhat
compromised because he did not know the exact quantity of food consumed and
digestion rates are influenced by meal size (see next section). Hunt (1960)
determined the digestion rates for the Florida gar, Lepisosteus platyrhincus,
the warmouth, Chaenobryttus gul os us , and the 1 a l"gemouth bass, Micropterus
salmoides. The fish were allowed to feed voluntarily or else were force fed
a known quantity of mosquitofish and the volume of the stomach contents
measured at predetermined intervals. Darnell and Meierotto (1962) studied
the feeding chronology of black bullheads, Ictalurus mel~s, by using a
standard food item as an indicator of the degree of digestion for the entire
stomach contents. The amphipod, Hyalella, was selected as the standard food
item since it made up more than half the bullheads natural diet. Fish were
collected and held in the 'laboratory where the digestion rate of the amphipods
was followed under controlled conditions. More fish were then collected
over a 24 hour period and the index of digestion for the amphipods was used to
establish the feeding chronology of the fish in nature. The food habits and
digestion rates of eight species of freshwater fish were investigaged by
Seabury and t10yle (1964). Fish were collected by seining, a subsample taken
for the immediate determination of stomach contents volume-, and the remaining
fish placed in food free live boxes on the lake bottom. At specified time
intervals the fish were removed from the live boxes for stomach contents
analysis. Alternatively, the fish were force-fed a known quantity of food
and their stomachs were pumped free of food for 'volume determinations, again,
at measured inte~vals. Pandian (1967) kept his fish, Megalops cyprinoides, at
2SoC and starved them for two days before determi~ing their digestion rate
when fed prawns weighing 2% of the fishes body weight. At measured time
intervals a fish was killed and the stomach contents weighed. A near linear
relationship between the percentage of food digested and time was found after
an initial lag period during which little weight loss of the stomach contents
was recorded. Windell (1966) also starved his fish, the bluegill sunfish,
Lepomis macrochirus, for a period of three days under constant temperature
conditions.' As in Pandian's experiment, the fish were fed a known quantity
of food and the percentage decrease in stomach contents measured over time.
However, Windell measured the digestion rate as digestible organic matter
which was defined as dry weight minus tne ash plus chitin weight. Thi's
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method was again used by Kitchell and Windell (1968) and Windell and Norris
(1969) when studying gastric digestion in the pumpkinseed sunfish, Lepomis
gibbosus, and rainbow trout, Salmo gairdneri, respectively .. Windell (1967,
1968) gives details of the methods involved in using the dried digestible
organic weight technique. Magnusun (1969) fed white bait of a known average
dry weight to skip jack tuna, Katsuwonuspelamis. Over the following 24 hours
the tuna were sacrificed and the quantity of food consumed was determined by
counting the number of partially digested fish in the stomach and multiplying
. this number by the average weight for the white bait. The decrease in dry
weight .was a meaSUl"e of the digestion rate. Tyle.r (1970) acclimated .young
cod to various temperatures and starved them fbr three days prior to feedih~
a standard meal of shrimp tails. Digestion rates were determined by
measuring the decrease in the dry weight of the stomach contents over time.
Brett and Higgs (1970) feed sockeye salmon, Oncorhynchus nerka, food pellets
of known biochemical composition. Fish were periodically anaesthetized,
frozen, and the frozen stomach contents dissected into preweighed crucibles
for determination of the dry organic weight. Beamish (1972) determined the
dry weight, protein N, lipid and caloric content of the stomach contents of
thermally acclimated large mouth bass, r~icroptey'us salmoides, following a
meal of shiners. Swenson and Smith (1973) used a rather ingenious method
of coding the food items fed to walleye, Stizostedion vitreum vitreum, in
order to quantify the digestion rate. Minnows VJere weighed to 0.1 gm and
then marked with a colored thread sewn below the dorsal fin. The walleye
were force fed the marked minnows which could later be identified and weighed
after the partially digested food was remoVed from the stomach using a
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stomach pump. Steigenberger and Larkin (1974) examined the feeding activity
and digestion rate of the northern squawfish, Ptychocheilus,oregonensis, by
force feeding a quantity of redside shiners to fish that had been starved
for 72 hours. They followed the digestion rate by pumping out the stomach
contents of anesthetized fish at six hour intervals for twenty four hours
after feeding. In an attempt. to avoid starving the fish prior to determining
the digestion rate, Daan (1973) maintained cod, Gadus morhua, on a diet
of shrimp for two weeks. He then switched the diet and fed a known weight
of sprat which could easily be distinguished from the shrimp remains in
the stcimach. Jones (1974), in his study of haddock, Melanogrammus aeglefinus,
cod, Gadus morhua, and whiting, Merlangius merl~ngus, compared three methods
of determining gastric evacuation rates. He fed a single meal to previqusly
starved fish and followed the digestion time or, kept them on a regular
feeding schedule and periodically sacrificed fish or, for haddock only)
followed their digestion rate after capturing the fish from an area where
they were known to be feeding on brittle stars. The first two methods gave
different results with the single meal experiment giving consistently lower
digestion rates than the regular feeding technique. The experiment with
brittle stars was not directly comparable since the actual quantity of prey
consumed was unknown. For anyone method, however, the digestion rate i.n
all three species was similar.
Although the following method has not recently been used in fish
digestion rate studies, it warrants mentioning since Riddle (1909) quotes
it as fi~st being used in 1783 by Spallanzani and Sonebrier. Glass tubes
(Mette's Tubes) are filled with coagulated egg albumen and placed in the fishes
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stomach. After a specified time interval the tubes are removed and the
. degree of digestion of the egg albumen noted. Riddle (1909) used this
technique with Amia calva while Pegel (1950) actually prepared an intestinal
fistula for the insertion of Mette's tubes in the foregut and hindgut of
Leuciscus 1. biacalensis. Mette's tubes were also used by Chepik (1964)
to study seasonal changes in the digestive enzyme activity of carp.
Radiographic Methods
The use of x-ray techniques can be particularly successful in studying
digestion of piscivorous fish species. The decreasing visibility of the
bony elements and swim bladder of the prey, together with a change in
position of these elements to each other, was used by Molnar et ale (1967)
to study digestion in a number of European fishes. Edwards (1971, 1973) also
used the x-ray technique to study digestion ration in plaice, Pleuron~ctes
platessa, but he fed the fish lugworms injected with barium sulphate so
that. the prey items were x-ray opaque. Other people have incorporated x-ray
markers into the fishes diet to monitor food translocation (Kevern, 1966;
Peters and Hoss, 1974). In some transparent species, ordinary photographs
may serve the same purpose as x-rays. For example, Rosenthal and Hempel
(1970) have investigated the digestion rate in transparent herring larvae
from photographs taken at two hour intervals.
Food Intake and Defecation
Various workers have estimated gut evacuation rates by observing the
time be~ween feeding and the production of faeces. This technique is farily
uncomplicated in fish like the caspian roach~ Rutilus r. caspius (Bokova, 1938),
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and the pond roach, Misgurnus(Scheuring 1928), where a small meal is
excreted as a single dropping. However, most fish larvae and miriophagous
adults will feed continuously and it is necessary to label a portion of the
diet so that it may be identified in the faeces. Rozin and Mayer (1961) fed
pellets to goldfish at a constant rate over a one hour daily feeding period.
They then substituted pellets containing carmine and timed the interval
until the production of colored faeces. The first colored faecal material
'was produced seven hours after ingesting the meal, but the remaining labelled
faecal material was produced from eight to twenty-four hours after ingestion.
Much work on larval or juvenile fishes has employed a similar technique of
feeding dye labelled food. (Lane and Jackson 1969; Blaxter 1965; and Laurence
1971.) It should be noted that measuring faecal production after a spe~ified
meal is not necessarily comparable with the previous methods described which
generally deal only with stomach evacuation times ..
FACTORS INFLUENCING GASTRIC EVACUATION
Various methodologies have been used in the digestion rate experiments
described in the first section of this review. Each of these methods result
in different experimental conditions which may have some influence on the
observed results. A number of specific factors have been identified which
are known to influence the rates of gastric digestion under experimental or
natural conditions and these are listed and discussed individually below.
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Temperature
For poikilotherms, the digestive rate, as with most metabolic processes,
is greatly influenced by temperature and the thermal history of the animal.
Temperature changes may affect the digestion rate by influencing any of the
following temperature-dependent functions: 1) feeding rate; 2) secretion
of digestive enzymes; 3) activity of digestive enzymes; 4) motility of the gut
and 5) assimilation of digested foods. Both Kapoor et. ale (1975) and Grove et ale
(1977) review most of the literature on temperature along with presenting figures
summarizing the effect of temperature on digestion in fish. (See Fig. 1)
In general Kapoor et ale (1975) concluded that every rise in temperature of
100 C wi1l increase the digestion rate by a facto~ of 3 or 4. However, not all
the fish used in his example were fully acclimated to the test temperature. If
the fish were completely thermally acclimated, the slope of the line relating
temperature and digestion rate would not necessarily be as steep. It should also
be noted that as the temperature approaches a fishes upper lethal limit the
digestion rate may be depressed and the fish wil"' not eat (Tyler, 1970).
Body Size
The relation between body size and digestion rate has been established for
a number of, different fish species. In general, bigger fish will digest a
greater amount of food than smaller fish. However, if the size of the fish is
taken into consideration, and the amount of food digested is expressed as per
gram of fish, smaller fish have a higher evacuation rate. For example, Pandian
(1967) found that a 5.12 g fish digested the same amount ~f food as a 90.6 g
fish in approximately one third the time. Since small fish have a relatively
hi~her digestion rate it might also be expected that they will consume
relatively more food per day. This has been found to'be true for at least
Curve til>.
1 2 3 4 :> 6 7
8 {}
0.4r--"""I"'-""-O--,.--.--...----.---.
0.2
0.1
0.05
0.02
-":- 0.01 :! ::J o . e O•005 e
f c ~ 0.002 et ., en
. :; 0.C01 '--~5-':-'.:O--:-!15:--"""2."..O--::2c1=5--::3..i:.·)-'
temp. (Oe)
Fish species Food
Fundtdus heteroclitus clam mantles M isgufnus jossilis .. Oligochaetes and Gammarus ltf ulltts barbatu8 Polychaetes ],1 icropterus salmoides Alburnus alb. Sebastes inermis 7 % of body weight Lucioperca lucioperca Alburnu8 alb. lctaluru~ pu.nctalu~ pellets
(Calculated from time of 50% depletion of stomach cont~nts)
shrimp tails Gadus morhua Oncorhynchus nerka canned salmon and pellets
Author
Nicholls, 1933 Scheuring, 1928 . Lipskaya, 1959 Fabian et al., 1963 Kariya, 1969 Molnar a.nd Tolg, 1962 Shrable et al .• 1969
Tyler. i970 Brett and Higgs, 1970'
Figure 1. Digestion rate in relation to temperature.
(From: Kapoor et. a1. 1975)
sockeye salmon. Brett (1971) fed different size ~roups of salmon an artificial
diet to determine the maximum daily voluntary food intake. When expressed as a
percentage of the dry body weight, he found that the diet dropped from an
average of 16.9% for a 4 g fish to 4.3% for a 216 g fish. In absolute
terms, though, the small fish consumed 0.68 g while the large fish ate
9.29 g.
Meal Size
In evaluating the effect of meal size on digestion, it is· important to
consider how various authors have presented theil~ data. The effects of meal
size have usually been expressed as the time t~kento empty the stomach or as
a percentage decrease against time. For example, Windell (1966) found that the
time for the stomach of a bluegill sunfish to empty following a small or large
meal of Tenebrio was similar. Clearly, however, the rate of digestion of the
larger meal (expressed as weight/unit time) must be greater. In general then, .~
it has been found that a larger meal i~ digested at a greater rate than a smaller
meal of a similar type (Hunt 1960; Beamish 1972; Swenson
and Smith, 1973; Joblinget a1. 1977). It may also be true that a smaller meal
is digested sooner than a larger meal, as suggested by Barrington (1957), because
of a larger surface to volume ratio. For example, a fourfold increase in the
ration size of a large mouth bass, Micropterus, only doubled the time required for the
fish's stomach to empty (Beamish, 1972). Likewise, an increase in ration size
from 1 g to 5 g for a 100 g dab, Limanda, caused a 3.8 fold increase
in the time for the stomach to empty (Jobling et ale 1977). In both examples,
however, the digestion time for the larger meal was offset by a greater rate of
digestion, perhaps due to a greater stimulation of enzyme secretion (Norris
et ale 1973) Dr gastric motility (Burnstock 1958).
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The rate of stomach evacuation has been found by Jdnes (1974) to be
related to meal size in three gadoids by the exponent O.46~ i.e., digestion
rate = (meal size)0.46. Windell et ale (1969), Mc Kone (1971), and Beamish (1972)
have found that digestion rate is related to meal size raised to the power 0.6,
0.7 and 0.75 for Salmo gairdneri, Prosopium and Micropterus respectively. In
one instance digestion rates have been found to be directly proportional to
the meal size (Windell, 1966) while Steigenberger and Larkin (1974) showed that
the digestion rate of Plychochei'lus actually decreased with.an increase in
meal size. As Grove et ale (1977) mentioned, many more species need to be
studied before this fish can be called anomalous.'
Diet Composition
Data on digestion of different food items suggests that the composition
of a fish's diet will have a substantial influence,on the rate of gastric
evacuation. There is apparently a lag period of variable duration after most
any food item enters the stomach and before it begins to be digested. For
example, Jones (1974) fed several gadoids a variety of fish and crustaceans in
an attempt to compare the digestion rate for different foods. Pollack was 'used
as the standard diet and it was found by extrapolation of a fitted regression line,
that the pollock remained in the stomach for approximately l~ hours, at 120 C,
before the stomach contents lost weight. Most other fish tested had similar lag
times except for Centronotus VJhich remained intact for up. to 20 hours. The
crustaceans, Crangon, Carcinus and Nephrops were similarly tested and remained in
the stomach unchanged anywhere from 10-40 hours. The differences in digestion
rate between fish and crustacea may be attributed to the presence of the hard and
thick exoskeleton of shrimps and crabs. Hard food parts have been observed by
Windell (1966, 1968), Edwards (1971), and Kionka and \'Jindell (1972), to take longer
to be evacuated from the stomach than softer more easily digestible food items.
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The difference in the digestion rate for the various fish species may relate to
differing biochemical composition or even hydrolysis of the food once it is in the
stomach. Karpevitch and Bokova (1936, 1937) showed that different foods are
digested at different rates and that fat retarded digestion. ,Windell (1967)
suggested that fat might influence the digestion rates observed in bluegill
sunfish while Windell et ale (1969) showed that diets with increasing fat levels
decreased the gastric evacuation rate in rainbow trout. Hydrolysis of a food
item has also been observed under experimental conditions'which resulted in an
initial depression of the observed digestion rate (Herting and Witt, 1968;
Steigenberger and Larkin, 1974).
A number of other workers have detected a decrease in digestion rate for
different food items. Elliott (1972) found that b~own trout evacuate gammarids
or oligochaetes in approximately 22 hours (l20 C) while Protonemura, Hydropsyche,
and Tenebrio took 26, 30 and 49.5 hours respectively. Pandian (l967) feeding
Megalops on Gambusia or Metapenaeus and Hestern (1971) feeding Cottus and Enophrys on
Tubifex, Calliphora or semifluid meals also found differential rates of digestion.
"Feeding'FreguencyandForce-Feeding
Experimental determination of digestion rates usually involves handling
the fish, a period of starvation in order to completely empty the stomach and,
either letting the fish feed voluntarily or force-feeding anesthetized animals.
These conditions all deviate from what a fish usually experiences in nature and
consequently the merits and disadvantages of various experimental techniques
have been discussed. Windell (1967) sites a number of papers describing the
physiological effects of handling fish and these may vary anywhere from
hyperglycemia to death. In any experimental situation, handling cannot be
avoided and one has to be satisfied that it is kept to a minimum.
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When measuring digestion rates, starvation of experimental animals should be ,
kept to a minimum, lasting only long enough to allow the animals to clear their
stomachs, or else avoided completely by feeding easily distinguishable food items.
The influence of starvation and feeding frequency in adult fi·sh have most recently
been investigated by Windell (1967), Tyler (1970) and Jones (1974). In general,
it was found that the digestion rates measured in previously starved fish were
only 50 to £0% of those in fish which were on a regular feeding schedule. Similar
results have been found for larval fish by Blaxter ~nd Holliday (1963), Laurence
(1971), Rosenthal and Paffenhofer (1972) and Nobel (1973).
Force-feeding is often used to insure that the fish consumed a known quantity
of food ~t a specified time. Few workers hav~ critically evaluated the effect that
force-feeding has on the fish. Hunt (1960), during a study of the digestion rate
of the Florida gar, warmouth and largemouth bass observed little difference
between fish that fed voluntarily and those that were force-fed. The influence of
forced versus voluntary feeding was compared statistically during a study of the
walleye by Swenson and Smith (1973). They concluded that force-feeding does in
fact bias the results obtained on digestion rates. Force-feeding decreased
the rate of gastric evacuation,as had been suggested by Windell (1966).
FACTORS AFFECTING FOOD HABITS DATA
The food supply for a fish population is one of the primary factors controlling
production. The purpose of collecting data on digestion rates is usually to use
the information together with estimates of the average amount of food in the fishes
stomach to establish the daily or yearly ration. In carrying out laboratory or
even field experiments to determine either the food habits or digestion rates, a
number of factors which may influence the results have to be considered. Some of
the major difficulties in studies of this type are discussed below.
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Feeding Chronology
The accurate determination of the daily feeding chronology requires sampling
of a fish population over a number of 24 hour periods. Consequently, this type of
experiment has only rarely been carried out successfully. Darnell and Meierotto
(1962) suggested a methodology for determining the 24 hour chronology of feeding
intensity in natural fish populations based on stomach contents analysis and
digestion rates for a standard food item. Using. this method they identified two
distinct feeding periods, one just before dawn and one shortly after dark, in a
population of black bullheads. Swenson and Smith (197~) evaluated the diel feeding
periodicity of walleye by collecting fish at t\AJO hour intervals over a total of
16 days." They calculated the percentage of the total meal consumed for each two
hour period and found that feeding was rhythmic at least from July through
September. Daily patterns of feeding intensity for other fish populations have
been observed by Keast and Welsh (1968), Holton (1969), Olla et al.(1969, 1974),
Narver (1970), Steigenberger and Larkin (1974), Merrett and Roe (1974), Timokhina
(1974), Thijssen et ale (1974), Baird et ale (1975), Girsa (1975), and
Ebeling and Bray (1976).
Sea~onal fluctuations in food habits have been observed for both freshwater
and marine fish. Seaburg and Moyle (1964) found a decrease in the quantity of
food in the stomach of some Minnesota lake fish over a summer long study of food
habits. For marine fish, difficulties in sampling the same population over a year.
compromise studies of seasonal changes in food habits. Despite this problem
Wigley and Theroux (1965), Vinogradov (1971) and Tyler (MS 1971) have found a
seasonal change in food habits for various marine fish.
Apart from daily and seasonal changes in food habits, sampling technique is
pro~ably the biggest factor influencing the estimates of daily rations made from
field samples. If the average amount of food in the ·siomach is used in calculating
. the ration, then two major sources of error may affect the results. First is the
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sample size. If, for example, fish feed ver'y intensely over a short period during
the day, too sm~l a sample could either grosslY overestimate or underestimate
the mean stomach contents weight. The second source of error is caused by the
length of time the fish are retained in the gear before the stomachs are removed
and the contents preserved. Food intake presumably ceases once the fish are caught
(Hopkins and Baird 1975) but gastric evacuation will continue. There are undoubtedly
other factors influencing the average stomach contents such as regurgitation and
swallowing other fish after being caught in the'gear, but these are difficult to quantify ...
The first two factors mentioned above have recently been incorporated into a simple
.differential equation model describing the level of food in the stomach (Eggers 1977).
CALCULATING DIGESTION RATES AND O'AILY RATIONS
A variety of techniques have been utilized 'in analyzing gastric evacuation
rates. Magnuson (1969), Kitchell (1970), and Swenson and Smith (1973) fitted a
first or second order polynomial regression to their data while Tyler (1970),
Brett and Higgs (1970) and Elliott (1972) found that an exponential regression
best described their results. In contrast, Daan (1973) fitted a straight line
regression to his data on gastric evacuation in cod. In comparing his data to
Tyler's (1970) data on cod, Daan states that the curvilinear fit described by Tyler
was primarily due to the last 10% of the stomach contents, and for at least the
initial phase of digestion a linear fit to the data would be adequate. Windell
et ala (1976) compared various methods in describing their data on gastric
evacuation by rainbow trout. Different regressions produced different predictions
with the greatest variation occurring when predicting the length of time necessary
to completely empty the stomach. They found that the time for complete stomach
evacuation could range from 22 to 35 hours ~epending entirely on the method used
to analyze the data. Because of the variability between methods) it was suggested
that the actual type of regression equation chosen to describe any data on evacuation
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rates be chosen statistically using an analysis of variance and F statistics.
In the case of Windell IS rainbow trout, a semilbg relationship of the form:
% evacuation = a + b log Time was chosen as the best fit regression.
Four equations have been proposed which may be used to c.alculate estimates
of the daily ration. Bajkov (1935) suggested the following formula:
where: D = the daily ration
D = A 24 n
A = the average amount of food in the stomach
n = the number of hours necessary to completely empty the stomach
Bajkov's formula assumes that feeding is effectively continuous, that
digestion continues at the same rate throughout the day and that the amounts
and kind of food do not influence the rate of gastric evacuation. Since most
of these assumptions are not valid, Davis and Warren (1968) do not recommend the
use of Bajkov's formula. Nevertheless, this methodology had been adopted and
modified slightly by Darnell and Meierotto (1962) and Seaburg and Moyle (1964)
in their calculation of the daily ration of some freshwater fishes.
A second formula has been suggested by Daan (1973):
where: ~L = daily ration for a given length fish
wL = average weight of the stomach contents for a given length fish
DL ; digestion time in days for a given length fish
Rewriting the equation in Bajkovls terms, it becomes:
D = 2 • A n
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From the resul ts of 1 aboratory experiments, Daan assumed that gastr.i c evacuati on was
a linear function of time and therefore the daily ration was twice the average
amount of food in the stomach divided by the time for gastric evacuation. This
assumption, however, does not consider feeding periodicity and the possibility that
there is a differential rate of digestion for the various prey items. The formula,
therefore, suffers from some of the inadequacies which were discussed in reference
to Bajkov's equation.
The third method for calculating the daily ration has been. proposed by Swenson
and Smith (1973) and is of the form:
C - Lt Lt (-L·f SC)
F
where: C = daily food consumption in grams for the .average fish
SC = weight of the undigested stomach contents for foods of a given
size and not more than 90% digested, during a specified time period
Lf = summation'of corrected weight of stomach contents for all the
fish in the sample, having consumed food nf a given size, during a
specified time period
F = number of fish in the sample which could have contained food of a
given size, not more than 90% digested, during a specified time period
LS = summation of food sizes
Lt = summation of time
The use of Swenson and Smith's method requires the determinafion of the degree of
digestion of the food items in the stomach and the establishment of length-weight relation
ships for the various prey items so that the original weight of an item may be estimated
from the partially digested ramains. This technique is similar to that of Fortunatova
(1950, 1951, 1955; See also Popova 1967) and has apparently been used extensively by Russian
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workers (see Davis. and Warren, 1968). The major difficulty in ,using this
technique would be establishing accurate estimates of the "reconstructedll
weight for the variety of prey items eaten by various fish. It is most
appropriate for piscivorous fish which feed infrequently.
Another approach for calculating the daily ration would be to measure
growth rate and metabolic rate and then calculate the ration necessary to
sustain the fish. Winberg (1956) proposed the following formula for calculat
ing food consumption:
where: C = consumption
R = respiration
LlB = growth
c = 1 .25 (R + AB)
Estimating food consumption in nature from laboratory growth studies using
coho salmon has been attempted by Carline and Hall (1973). They held fish in
an outdoor stream tank, where natural social behavior patterns were established,
and compared the growth with fish held individually in restrictive aquaria. The
growth rate of the groups fed identical rations was similar and it was concluded
that laboratory growth data could be useful in field extrapolations as had been
suggested by Davis and Warren (1968). This technique may be used in conjunction
with the methods estimating daily consumption based on stomach contents as a
check on some of the assumptions and apparent shortcomings of those methods
(Backiel 1971; Adams 1974).
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REFERENCES
Adams, S. M. 1974. Structural and Functional Analysis of Eelgrass Fish Communities. Ph.D. thesis, The University of North Carolina at Chapel Hill. 131 pp. '
Backiel, T. 1971. Production and Food Consumption of Predatory Fish in the Vistula River. J. Fish Biol. 3, 369-405.
Bajkov, A.D. 1935. How to Estimate the Daily Food Consumption of Fish Under Natural Conditions. Trans. Am. Fish. Soc. 65, 288-289.
Baird, R. C., T. L. Hopkins and D. F. Wilson. 1975. Diaphus taaningi Norman in the Cariaco Trench.
Feeding Chronology of Copeia 1975, 356-365.
Barrington, C. J. W. 1957. The Alimentary Canal and Digestion. In: M. E. Brown (ed). The Physiology of Fishes, Vol. 1. pp. 109-161. Academic Press, New York.
Beamish, F. W. H. 1972. Ration Size and Digestion in Largemouth Bass, Micropterus salmoides Lacepede. Can. J. Zool. 50. 153-164.
Blaxter, J. H. S. 1965. The Feeding of Herring Larvae and their Ecology in Relation to Feeding. Calif. Coop. Ocean. Fish. Invest., Vol. 10, 79-88.
Blaxtet, J. H. S. and F. G. T. Holliday. 1963. The Behavior and Physiology of Herring and other Clupeids. Adv. Mar. Biol. Vol. 1,261-393.
Bokova, E. 1938. Daily Food Consumption and Digestive Rate in Rutilus Rutilus. Rybnoje Khosyajstvo No. 6 (In Russian)
Brett, J.R. 1971, Satiation time, appetite, and maximum food intake of Sockeye Salmon (Oncorhynchus nerka). J. Fish. Res. Bd. Can. 28, 409-415.
Brett, J. R. and D. A. Higgs. 1970. Effect of Temperature on the Rate of Gastric Digestion in Fingerling Sockeye Salmon, Oncorhynchus nerka. J. Fish. Res. Bd. Can. 27, 1767-1779.
Burnstock, G. 1958. The Effect of Drugs on Spontaneous Motility and the Response to Stimulation of the Extrinsic Nerves of the Gut of a Teleostean Fish., Brit. J. Pharmacal. 13,216-226.
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Carline,'R.F. and J. D. Hall. 1973. Evaluation of a Method for Estimating Food Consumption Rates of Fish. J. Fish. Res. Bd. Can. 30. 623-629.
Chepik, L. 1964. Activity of Carp Digestive Enzymes at Different Seasons of the Year. Biological Abstracts 47, (1966) 60747.
Daan, N. 1973. A Quantitative Analysis of the Food Intake of North Sea Cod, Gadus morhua. Neth. J. Sea Res. 6, 479-517.
Darnell, R. M. ,and R. R. Meierotto. 1962. Determination of Feeding Chronology in Fishes. Trans. Am~ Fish. Soc. 91, 313-320. '
Davis, G. E. and C. E. Warren. 1968. Estimation of Food Consumptinn Rates. In: W. E. Ricker (ed.). Methods for Assessment of Fish Production in Fresh Waters. Chapter 10, pp 204-225. IBP Handbook No.3 B1.ackwell Scientific Publications, Oxford and Edinburgh.
Ebeling, A. W. and R. N. Bray. 1976. Day Ver~usNight Activity of Reef Fishes in a Kelp Forest off Santa Barbara, California. Fish Bull. 74, 703-717.
Edwards, D. J. 1971. Effect of Temperature on Rate of Passage of Food' through the Alimentary Canal of the Plaice Pieuronectes Platessa L. J. Fish. Biol. 3,443-439.
1973. The Effects of Drugs and Nerve-Section on the Rate of Passage of Food through the Gut of the Plaice, Pleuronectes Platessa L. J. Fish Biol. 5,441-446.
Eggers, D. M. 1977. Factors in Interpreting Data Obtained by Diel Sampling of Fish Stomachs. J. Fish. Res. Bd. Can. 34, 290-294.
Elliott, J. M. 1972. Rates of Gastric Evacuation in Brown Trout, Salmo trutta L. Freshwater Biology 2, 1-18.
Fabian, G., Molnar and I. Tolg. 1963. Comparative Data and Enzyme Kinetic Calculations on Changes Caused by Temperature in the Duration of Ga~tric Digestion of some Predatory Fishes. Acta Biologica Academiae Scientiarum ' Hungaricae 14, 123-129.
Fortunatova, K. R. 1950. (Biology of Feeding of Scorpaena Porcus L.) Trudy secastopol. biol. Sta. 7, 193~235.
Fortunatova, K. R. 1951. (Methods of Studying Feeding of Predacious Fishes. I.) Zool. Zh. 30, 562-571.
1955. (Methods of Studying Feeding of Predacious Fishes. II.) Trudy Soveshch. po metodam izuchen. korm. bazi i pitania ryb. Akad. Nauk USSR, 62-84.
Girsa, I. I. 1975. The diurnal Rhythm in the Feeding of Underyear1ings of' some White Sea Fish at Different Photoperiods. J. Ichthyo1. USSR 15, 102-110.
Grove, D. J. et ale 1977. Manuscript in Preparation.
Herting, G. E. and A. Witt, Jr. 1968. Rate of Digestion in the Bdwfin. Prog. Fish Cult. 30,.26-28 ..
Holton, A. A. 1969. Feeding Behavior of Vertically Migrating Lanternfish. Pac. Sci. 23, 325-331.
Hopkins, T. L. and R. C. Baird. 1975. Net Feeding in Mesopelagic Fishes. Fishery Bulletin 73, 908-914.
Hunt, B. P. 1960. Digestion Rate and Food Consumption of Florida Gar, Warmouth and Largemouth Bass. Trans. Am. Fish. Soc. 89, 206-210.
Jobling, J., D. Gwyther and D. J. Grove. 1977. Some Effects of Temperature, Meal Size and Body weight on Gastric Evacuation in the Dab Limanda 1imanda (L). J. Fish Biol. 10, 291-298.
Jones, R. 1974. The Rate of Elimination of Food from the Stomachs of Haddock, Melanogrammus aeglefinus, Cod, Gadus morhua and VJhiting, Merlangius merlangus. J. Cons. into Explor. Mer. 35, 225-243.
Kapoor, B. G., H. Smit and I. A. Verighina. 1975. The Alimentary Canal and DiQestion in Teleosts. Adv.,mar. Bio1. 13, 109-239.
Kariya,'T. 1969. The Relationship of Food Intake to the Amount of Stomach Contents in Mebaru, Sebastes inermis. Bull. Jap. Soc. Scient. Fish. 6, 533. Abstract only.
Karpevitch, A. F. and N. E. ~Bokova. 1936. The Rate of Digestion in Marine Fishes Pt. I. Zoologicheskij Zhurnal 15, 143-168. In Russian. (English translation by Z. Kabata, 1965. Dept. of Agriculture and Fisheries for Scotland, Translation #1004, 1-5.)
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Karpevitch, A. F. and E. N: Bokova .. 1937. The Rate of Digestion in Marine Fishes, Pt. II. Zoblogicheskij Zhurnal 16, 21-44. In Russian with English summary.
Keast, A. and L. Welsh. 1968. Daily Feeding Periodicities, Food Uptake Rates, and Dietary Changes with Hour of Day in Some Lake Fishes. J. Fish. Res. Bd. Can. 25, 1133-1144.
Kevern, N. R. 1966. Feeding Rate of Carp Estimated by a Radiosotopic Method. Trans. Am. Fish. Soc. 95, 363-371.
Kionka, B. C. and J. T. Windell.· 1972. Differential Movement of Digestable and Indigestable Food Fractions in Rainbow Trout, Salm0 gairdneri. Trans. Am. Fish. Soc. 101, 112-115.
Kitchell, J. F. 1970. The Daily Ration for a Population of Bluegill Sunfish (Lepomis macrochrius Raf.). Ph.D. Thesis, University of Colorado, Boulder. 83 pp.
Kitchell, J. F. and J. T. Hindell. 1968. Rate of Gastric Digestion in Pumpkinseed Sunfish, Lepomis gibbosus. Trans. Am. Fish. Soc. 97, 498-492.
Lane, T. H. and H. M. Jackson. 1969. Voidance Time for 23 Species of Fish. U.S. Bur. Sport. Fish. Wildl. Inv. in Fish COhtrol No. 33. 9 pp.
Laurence, G. C. 1971. Digestion Rate of Lar~al Largemouth Bass. N.Y. Fish Game J. 18, 52-56.
Lipskaya, N. A. 1959. Duration of Digestion in the Black Sea Surmullet (Mullus barbatus ponticus). Biological Abstracts 48 (1967), #26852.
Magnuson, J. J. 1969. Digestion and Food Consumption by Skiojack Tuna (Katsuwonus pelamis). Trans. Am. Fish. Soc. 98, 379-392'. '":,J,::',,
Markus, H. C. 1932. The Extent to which Temperature Changes Influence Food Consumption in Largemouth Bass (Huy'o floridana). Trans. Am. Fish. Soc. 62~ 202-210.
McKone, D. 1971. Rate at which Sockeye Salmon A1evins are Evacuated from the Stomach of Mountain Whitefish (Prosopium williamsoni). J. Fish. Res. Bd. Can. 28, 110-111.
Merrett, N. R. and H. S. J. Roe. 1974. Patterns and selectivity in the Feeding of Certain Mesopelagic Fish. Mar. Biol. 28, 115-126.
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Molnar, G. and I. Tolg. 1962. Experiments Concerning Gastric Digestion of Pike Perch (Lucioperca lucioperca L.) in relation to water temperature. Acta Biologica Academiae Scientiarum Hungaricae 13, 231-239.
Molnar, G., E. Tamassy and I. Tolg. 1967. The Gastric Digestion of Living Predatory Fish. In: S. D. Gerkin (ed.) The Biological Basis of Freshwater Fish Production. Blackwell Scientific Public?tions, pp. 137-149, Oxford and Edinburgh.
Narver,D. W. 1970. Diel Vertical Movements of Underyearling Sockeye Salmon and the Limnetic Zooplankton in Babine Lake, British Columbia .
. J. Fish. Res. Bd. Can. 27, 281-316.
Nicholls, J. V. V. 1933. The Influence of Temperature on Digestion in Fundulus heteroclitus. Contributions to Canadian Biology and Fisheries 7, 47-55.
Nobel, R. L. 1973. Evacuation Rates of Young Yellow Perch, Perca flavesieus (Mitchell). Trans. Amer. Fish. Soc. 102, 759-763.
Norris, J. S., D. O. Norris and J. T. Windell. 1973. Effect of Simulated Meal Size on Gastric Acid and Pepsin Secretory Rates in Bluegill (Lepomis macrochirus)~ J. Fish. Res. Bd. Can. 30, 201-204.
Olla, B. L., R. Wicklund and S. Wilko 1969. Behavior of Winter Flounder in a Natural Habitat. Trans. Am. Fish. Soc. 98!j 717-720.
Olla, B. L., A. J. Bejda and A. D. Martin. 1974. Daily Activity, Movements, Feedi ng, and Seasona 1 Occ'urence i·n the Tautog, Tautoga oni ti s. Fi shery Bulletin 72, 27-35.
Pandian, T. J. 1967. Intake, Digestion, Absorption and Conversion of Food in the Fish Megalops cyprinoides and Ophiocephalus striatus. Marine Biol. 1, 16-32.
Pegel, V. A. 1950. Digestive Physiology of Fishes. Tomskij Gosudarstvennyj Universitet Tomsk. 199 pp. In Russian.
Peters, D. S. and D. E. Hoss. 1974. A Radioisotopic Method of Measuring Food Evacuation Time in Fish. Trans. Am. Fish. Soc. 103, 626-629.
Popova, O. A. 1967. The Predator-Prey Relationship among Fishes. (A Survey of Soviet Papers). In: S. D. Gerking (ed.). The Biological Basis of Freshwater Fish Production. pp. 359-376. John Wiley and Sons, Inc., New York.
Riddle, O. 1909. The Rate of Digestion in Cold-Blooded Vertebrates - The Influence of Season and Temperature. Am. J. Physiol. 24, 447-458.
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Rosenthal, H. and~G. Hempel. 1970. Experimental Studies in Feeding and Food Requirements of Herring Larvae. In: J. H. Steele (ed.). Marine Food Chains, pp. 344-364. University of California Press, Berkeley.
Rosenthal, H. and G. A. Paffenhofer. 1972. On the Digestive Rate and Calorific Content of Food and Feces in Young Gar Fish. Naturwissenschaften 59, 274-275.
Rozin, P. and J. Mayer. 1961. Regulation of Food Intake in Goldfish. Am. J. Physiol. 201, 968-974.
Scheuring, L. 1928. Beziehungen zwischen Temperatur und Verdauungsgeschwindigkeit bei Fischen. Z. Fisch. 26, 231-235 ..
Seaburg, K. G. and J. B. Moyle. 1964. Feeding Habits, Digestive Ratei, and Growth of some ~1innesota Warmwater Fishes. Trans. Am. Fish. Soc. 93, 269-285.
Shrable, J. B., O. W. Tiemeier and C. W. Deyoe. 1969. Effects of Temperature on R~te of Digestion by Channel Catfish. Prog. Fish-Cult. 31. 13l-138.
Steigenberger, L. W. and P. A. Larkin. 1974. Feeding Activity and Rates of Digestion of Northern Squawfish (Ptychocheilus oregonensis). J. Fish. Res. Bd. Can. 31, 411-420.
Swenson, W. A. and L. L. Smith, Jr. 1973. Gastric Digestion, Food Consum~tion, Feed i ng Peri od i city and Food Convers i on effi c i ency in \AJa 11 eye (Stizostedion vitreum vitreum). J. Fish. Res. Bd. Can. 30, 1327-1336.
Thijssen, R., A. J. Lever and J. Lever. 1974. Food Composition and Feeding Periodicity of O-Group Plaice (Pleuronectes platessa) in the Tidal Area of a Sandy Beach. Neth. J. Sea Res. 8, 369-377.
Timokhina,A. F. 1974. Feeding and Daily Food Consumption of the Blue Whiting (Micromesistius poutassou) in the Norwegian Sea. J. Ichthyology 14, 760-765.
Tyler, A. V. 1970. Rates of Gastric Emptying in Young Cod. J. Fish. Res. Bd. Can. 27, 1177-1189.
1971. Monthly Changes in Stomach Contents of Demersal Fishes in Passamaquoddy Bay, N.B. J. Fish. Res. Bd. Can. Tech. Rep. 288, 119 pp.
Vinogradov, V. I. 1972. Studies of the Food Habits of Silver and Red Hake in the Northwest Atlantic Area, 1965-67. ICNAF Research Bulletin 9, 10 pp.
Western, J. R. H. 1971. Feeding and Digestion in Two Cottid Fishes, the Freshwater Cottus gobio L.and the marine Enophrys bubalis (Euphrasen). J. Fish. Biol. 3, 225-246. .
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Wigley, R. L. and R. B. Theroux. 1965. Seasonal Food Habits of Highland Ground Haddock. Trans. Am. Fish. Soc. 94, 243-251.
Winberg, G. G. 1956. Intensivnost ' ovmena i pishchevye potrebnosti rYe (Rate of metabolism and food requirements of fishes.) Nauchnye Trudy Belorusskogo Gosudarstvennogo Universiteta ineni V. I. Lenina, Minsk. 253 p. Fish. Res. Bd. Trans. #194.
Windell, J. T. 1966. Rate of Digestion in the Bluegill Sunfish. Invest. Indiana Lakes Streams 7, 185-214.
1967. Rates of Digestion in Fi~hes. In:" S. D. Gerking (ed.). The Biological Basis of Freshwater Fish Production pp. 151-173. John Wiley and Sons, Inc., New York.
1968. Food Analysis and Rate of Digestion. In: W. E. Ricker (ed.). Methods for the Assessment of Fish Production in Fresh Waters. Chapter 9. pp. 197-203. IBP Handbook No.3, Blackwell Scientific Publications, Oxford and Edinburgh.
Windell, J. T. and D. O. Norris. 1969. Gastric.Digestion and Evacuation in Rainbow Trout. Prog. Fish Cult. 31, 20-26.
Windell, J. T., D. O. Norris, J. F. Kitchell and J. S. Norris. 1969. Digestive Response of Rainbow Trout, Salmo gairdneri, to pellet diets. J. Fish. Res. Bd. Can. 26, 1801-1812.
Windell, J. T., J. F. Kitchell, D. O. Norris, J. S. Norris and J. W. Foltz. 1976. Temperature and Rate of Gastric Digestion by Rainbow Trout, Salmo gairdneri. Trans. Am. Fish. Soc. 105, 712-717.
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References
Bowman, R.E. 1975. Food habits of Atlantic cod, haddock and silver hake in the Northwest Atlantic, 1969-1972. Laboratory Reference No. 75-1.
Bowman, R. E ., R. O. Maurer and J. A. Murphy. 1976.." Stomach contents of twenty-nine fish species from five regions in the Northwest Atlantic -data report. Laboratory Reference No. 76-10.
Bowman, R. E. 1977. Seasonal food habits of demersa 1 fi sh "i n the Northwest Atlantic. Laboratory Reference No. 77-01.
Langton, R.W. and R.E. Bowman. 1977. The food habits· of sixteen species . of fish collected in the region of the Arqo Merchant oil spill.
Laboratory Reference No. 77-04.
Maurer, R.O. and R.F. Bowman. 1975. Food habits of marine fishes of the Northwest Atlantic - data report. Laboratory Reference No. 75-3.