NOAA Technical Memorandum NMFS-NWFSC-102

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Biochemistry of Red King Crab

(Paralithodes camtschaticus)

from Different Locations

in Alaskan Waters

September 2009
NOAA Technical Memorandum

NMFS-NWFSC Series

The Northwest Fisheries Science Center of the National 

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and technical publications. Manuscripts have been peer 

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may be cited in the scientific and technical literature.

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Alaska Fisheries Science Center, which has since been 

split into the Northwest Fisheries Science Center and the 

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Fisheries Science Center.

Reference throughout this document to trade names does 

not imply endorsement by the National Marine Fisheries 

Service, NOAA.

This document should be referenced as follows:

Reppond, K.D. 2009. Biochemistry of red king crab (Paralithodes camtschaticus) from different locations in Alaskan 

waters. U.S. Dept. Commer., NOAA Tech. Memo. NMFSNWFSC-102, 16 p. 
NOAA Technical Memorandum NMFS-NWFSC-102

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Biochemistry of Red King Crab

(Paralithodes camtschaticus)

from Different Locations

in Alaskan Waters

Kermit D. Reppond

Northwest Fisheries Science Center

Resource Enhancement and Utilization Technologies Division

Manchester Research Station

7305 East Beach Drive

Port Orchard, Washington 98366

September 2009
ii

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Table of Contents 

List of Tables ................................................................................................................................................v 

Executive Summary ....................................................................................................................................vii 

Acknowledgments........................................................................................................................................ix 

Introduction...................................................................................................................................................1 

Methodology.................................................................................................................................................3 

Collection of Crab and Preparation of Samples .......................................................................................3 

Biochemistry.............................................................................................................................................4 

Statistical Analysis ...................................................................................................................................4 

Results...........................................................................................................................................................5 

Biometrics.................................................................................................................................................5 

Hepatopancreas Biochemistry ..................................................................................................................7 

Ovary Biochemistry..................................................................................................................................8 

Eggs Biochemistry..................................................................................................................................10 

Discussion...................................................................................................................................................13 

References...................................................................................................................................................15 

iii
iv
List of Tables 

Table 1. Mean and SD of CL, whole weight, egg clutch weight, ESI, hepatopancreas weight, HSI, 

ovary weight, and GSI of red king crab from different locations.................................................................6 

Table 2. Number of samples and probability of correlation coefficient of CL, whole weight, egg 

weight, hepatopancreas weight, ovary weight, ESI, GSI, and HSI of red king crab. ...................................7 

Table 3. Nested ANOVA of red king crab hepatopancreas composition where location replicates are 

nested within location ...................................................................................................................................8 

Table 4. Mean and SD of proximate composition of hepatopancreas and ovary tissue of red king crab 

from different locations.................................................................................................................................9 

Table 5. Correlation coefficient and associated probability of hepatopancreas moisture, ash, and lipid 

content with CL, whole weight, egg weight, hepatopancreas weight, ESI, GSI, and HSI .........................10 

Table 6. Nested ANOVA of red king crab ovary composition where location replicates are nested 

within location ............................................................................................................................................10 

Table 7. Correlation coefficient and associated probability of red king crab ovary moisture, ash, and 

lipid content with CL, whole weight, egg weight, hepatopancreas weight, ESI, GSI, and HSI.................11 

Table 8. Nested ANOVA of red king crab egg composition where location replicates are nested 

within location ............................................................................................................................................11 

Table 9. Correlation coefficient and associated probability of red king crab egg moisture, ash, and 

lipid content with CL, whole weight, egg weight, hepatopancreas weight, ESI, GSI, and HSI.................12 

v
vi
Executive Summary 

Samples of female red king crabs (Paralithodes camtschaticus) from Bristol Bay and the 

Pribilof Islands, Kodiak Island, and Petrel Bank were taken in June, September, and November 

2006, respectively. Whole crab weight and the usual biometric parameters were recorded as well 

as weight of the ovary, hepatopancreas, and eggs. Moisture, ash, total lipid, and protein content 

of each organ were determined to investigate whether differences in biochemistry existed among 

crab from different areas and to initiate annual examination of these values to determine the 

extent of year-to-year variability. 

Relative gonadosomatic index values of crab from the different areas were consistent 

with the time interval between date of capture and typical mating season in their respective areas. 

Therefore, gonadosomatic index values were used as the estimator of the stage of annual 

reproductive cycle, as it was not possible to determine the stage of embryonic development. 

Crabs from Kodiak Island and Petrel Bank were further along in the reproductive cycle than 

crabs from Bristol Bay or the Pribilof Islands. The weight of the hepatopancreas relative to 

whole weight was the same in samples from the four areas. 

Crabs from Kodiak Island and Petrel Bank had higher lipid content in the hepatopancreas 

and ovary than crabs from Bristol Bay and the Pribilof Islands on a dry weight basis. Eggs of 

crabs from Kodiak Island had higher lipid content than crab from other areas. This may indicate 

that crabs from Kodiak Island had higher lipid content at fertilization. 

The results of this preliminary study indicate that a more extensive experiment, in which 

crab would be taken from the same area throughout the yearly cycle, would greatly benefit our 

understanding of the biochemical changes associated with reproduction. Determination of the 

fatty acid profiles and lipid classes of the lipid from such samples would also provide valuable 

information on the nutritional status of this species. 

vii
viii
Acknowledgments 

For providing samples and collected biometric information on crabs from Bristol Bay and 

the Pribilof Islands, I thank personnel from the Resource Assessment and Conservation 

Engineering Division of the Alaska Fisheries Science Center. For providing samples and 

collecting biometric information on crabs from Kodiak Island and Petrel Bank, I thank Kally 

Spalinger and other personnel of the Kodiak office of the Alaska Department of Fish and Game 

Shellfish Division, and Ryan Burt of the Dutch Harbor office of the Shellfish Division, 

respectively. 

ix
x
Introduction 

The decline of the red king crab (Paralithodes camtschaticus) population and its failure 

to recover despite two decades of restricted fishing is an enduring and perplexing problem for 

those tasked with the management of biological resources in the Bering Sea and the Gulf of 

Alaska. Commercial catch peaked in 1980 at 130 million lb but dropped quickly thereafter and 

has remained low (NPFMC 2008). The population has averaged 12.9 million legal-sized males 

over the last 5 years in the Bristol Bay and Pribilof Islands areas (Chilton et al. 2008). 

While there is no widely accepted consensus as to what caused the collapse of the king 

crab fishery or why it has failed to recover, one possibility is climatic change. Anderson and 

Piatt (1999) noted the occurrence of an ocean climate regime shift from cold to warm in the Gulf 

of Alaska in 1977 that resulted in a decrease in fatty forage species. Conners et al. (2002) 

reported a similar climate change in the southeastern Bering Sea in the early 1980s. Crabs may 

not be obtaining optimal levels of certain nutrients such as essential fatty acids that are necessary 

for reproduction. 

The role of nutrition of female crustaceans on reproductive success has been studied, 

especially for species associated with commercial aquaculture (Harrison 1990, Wouters et al. 

2001). Ovarian development in crustaceans during the annual reproductive cycle is not only 

marked by an increase in mass, but also changes in biochemical composition (Teshima et al. 

1988, Harrison 1990, Smith et al. 2004). 

It is believed that dietary lipids accumulate in the hepatopancreas of decapods and are 

then transferred to the ovary during the annual reproductive cycle (Teshima et al. 1988, Harrison 

1990). A diet high in polyunsaturated fatty acids resulted in an increase in ovary weight, 

fecundity, and egg hatch rate in Chinese mitten crab (Eriocheir sinensis) (Wen et al. 2002). 

Fecundity was correlated with eicosapentaenoic acid (EPA), C20:5(n-3), content and hatch rate 

with docosahexaenoic acid (DHA), C22:6(n-3), content of the eggs. Both fecundity and hatch 

rate were affected by n-3/n-6 fatty acid ratio (Wen et al. 2002). Xu et al. (1994) reported that 

diets low in the omega-3 fatty acids EPA and DHA resulted in reduced fecundity and 

hatchability in Chinese prawn (Fenneropenaeus chinensis). Larvae from spiny rock lobster 

(Jasus edwardsii) fed a beef-based diet were smaller, had a lower survival rate, and were less 

active than those from wild broodstock (Smith et al. 2004). Rosa et al. (2007) reported that the 

fatty acid profiles of decapod embryos reflected differences in diet and ecological niche. 

It may be possible to use total lipid content, fatty acid profile, and lipid profile as an 

indicator of the nutritional status of king crab. Differences in nutritional status among crab from 

different locations or from one year to the next may add an important metric in addition to the 

usual biometric data in assaying the health of various crab stocks. For this study, samples of red 

king crab for biochemical analysis could be obtained during the annual survey of crab population 

by the National Marine Fisheries Service (NMFS) and the Alaska Department of Fish and Game 
(ADF&G). The primary objective was to compare the biochemical profile of hepatopancreas, 

ovaries, and embryos of red king crab taken from different locations in Alaskan waters and to 

establish a baseline to determine whether these profiles change from year to year or vary due to 

location. 

2
Methodology 

Collection of Crab and Preparation of Samples 

Crabs from Bristol Bay (BB) and the Pribilof Islands (PI) were obtained during the 

annual NMFS survey in June 2006, conducted by the Resource Assessment and Conservation 

Engineering Division of the Alaska Fisheries Science Center. Crabs from Uyak Bay, Kodiak 

Island (KI), were obtained during survey work of the Shellfish Division of the ADF&G Kodiak 

office in September 2006. Crab from the Petrel Bank (PB) (lat 57.42°N, long 153.82°W), were 

obtained during survey work of the Shellfish Division of the ADF&G Dutch Harbor office in 

November 2006. Biometric information recorded included carapace length (CL), shell and egg 

clutch condition, and whole weight. For crab caught by NMFS, the standard codes for biometric 

information were used as follows: 

Shell condition Clutch size Egg color 

0 Pre-molt 0 Immature 0 No eggs 

1 Soft and pliable 1 Mature, no eggs 1 [Not used] 

2 Thin and clean 2 Trace to 1⁄8 full 2 Purple 

3 Hard shell, slightly worn 3 1⁄4 full 3 Brown 

4 Hard shell, worn 4 1⁄2 full 4 Orange 

5 Hard shell, very worn 5 3⁄4 full 5 Purple-brown 

6 Full 6 Pink 

For crab caught by ADF&G, biometric codes were converted to those used by NMFS for 

ease of comparison. During the NMFS survey, it was possible to accurately weigh whole crab at 

sea; the crab were then sacrificed to obtain the egg clutch, ovary, and hepatopancreas. The egg 

clutch was removed by snipping the pleopods with a pair of scissors and transferred to a 

resealable plastic bag. The ovary and hepatopancreas were similarly removed and transferred to 

separate, resealable plastic bags. Excess air was expelled prior to closing, then the specimens 

were frozen and kept frozen until further analysis. These samples were landed at Dutch Harbor 

and shipped by air to Kodiak. For KI samples, all four crabs were frozen whole at sea, as there 

was no access to a motion compensated balance needed to obtain whole weights if the seas were 

not calm. For the PB samples, only three crabs could be processed at sea while eight were frozen 

whole. PB samples were landed at Dutch Harbor and shipped by air to Kodiak. For whole 

specimens frozen at sea, crab were tempered overnight at 4°C in a cool room prior to being 

processed to obtain biometric data. Since the crab were not completely thawed, it was possible 

to obtain whole weights without compensating for thaw drip. Specimens were then thawed 

enough to obtain tissue samples. 

Eggs were stripped from pleopods with forceps and the egg clutch weight recorded. 

While it was possible to process the egg clutches from crab frozen whole, freezing and thawing 

sometimes had a detrimental effect on the hepatopancreas, so the weight of the hepatopancreas 

was not recorded from those specimens. The ovary tissue from crab frozen whole was not as 

3
detrimentally affected as the hepatopancreas tissue, but it was not possible to recover the entire 

ovary in every case. For those specimens whose organs were intact enough for reliable 

measurements, the gonadosomatic index (GSI) was calculated as follows. 

GSI = ovary weight × 100/whole weight 

Indexes for egg clutch weight (ratio of egg weight to body weight, aka eggsomatic index 

[ESI]) and hepatopancreas (hepatosomatic index [HSI]) were similarly calculated. 

Biochemistry 

For tissue samples from crab processed at sea, the samples were partially thawed at 4°C 

and weight was recorded. For egg clutches, eggs were stripped from the pleopods using forceps, 

and the weight of eggs recorded. Hepatopancreas and ovary tissue was homogenized using a 

PowerGen Model 125 homogenizer (Fisher Scientific, Pittsburgh, Pennsylvania) equipped with a 

10 mm generator prior to being assayed for proximate analysis. Material not needed for 

proximate analysis was placed either in amber glass vials or plastic containers, flushed with 

nitrogen, and stored at –80°C. Tissue samples from crab frozen at sea were similarly treated. 

Determination of moisture, ash, protein, and total lipid content was performed in duplicate using 

the methods of Reppond et al. (2008). Ash, lipid, and protein values were converted to a dry 

weight basis to compensate for differences in moisture content among samples. Protein content 

was not determined on all samples. In some cases, there was insufficient material left once 

samples were taken for other analyses. In other cases, the instrument used for protein analysis 

was under repair and was unavailable until after the experiment had to be terminated due to 

closure of the lab. 

Statistical Analysis 

Ten crabs were obtained from BB, while 2, 4, and 11 crabs came from PI, KI, and PB, 

respectively. These are referred to as location replicates. Biometric data were subjected to a 

one-way analysis of variance (ANOVA) to determine the effect of location. Moisture, ash, and 

lipid data were subjected to a nested ANOVA where experimental results for location replicates 

were nested within location using SAS 6.2 statistical programming (SAS Inc., Cary, North 

Carolina). Protein values were not subjected to a nested ANOVA because data was not available 

for all samples. To make comparison among locations easier, the mean moisture, ash, lipid, and 

protein values of each location replicate were calculated and used in a least significant difference 

determination using Statistical Package for Social Sciences 6.1 (SPSS Inc., Chicago, Illinois). 

Correlation coefficients among mean experimental values were determined using the same 

programming. 

4
5

Results 

Biometrics 

Crabs from BB and KI were all shell code 2, while both crabs from the PI area were 

classified as shell code 1. Eight of the PB crabs were shell code 2, and three were shell code 3. 

Egg clutch size codes were either 5 (3/4 full) or 6 (full) for crabs from each location. Of the 

crabs from BB, eight had clutch size code 5 and two had clutch size code 6. All the crabs from 

PI had clutch size code 6 and all the crabs from KI had clutch size code 5. Eight of the crabs 

from PB had clutch size code 5, and three had clutch code size 6. Eggs of crabs from BB, PI, 

and KI were all uneyed. Eight of the PB crabs had uneyed eggs, while three were eyed. Egg 

color was either purple or purple-brown in all samples with only a few classified as brown as 

follows: 

Purple Brown Purple-brown

Bristol Bay 3 1 6 

Pribilof Islands 2 – – 

Kodiak Island 1 1 2 

Petrel Bank 5 1 2 

Crabs from BB and PI had recently mated, and it was not always possible to locate and 

remove the ovary from the other organs due to its small size. Therefore, some crabs from BB 

lacked ovary data but had a sufficiently sized egg clutch and hepatopancreas for those organs to 

be analyzed. Unfortunately, only two crabs were available from PI, but their ovaries were large 

enough for sampling. Difficulties with obtaining ovary and hepatopancreas samples from PB 

crabs are described in the Methodology section. 

Crabs from BB were smaller than crabs from the other locations whether measured by CL 

or whole weight (Table 1). Crabs from KI were heavier than those from BB or PB but similar to 

those from PI. By weight, crabs from BB had the smallest amount of eggs as might be expected 

by the relative size of the crabs. PI and KI crabs had the highest egg weight with PB crabs 

somewhat lower. Since larger crab would be expected to have a larger egg mass, a more useful 

measurement would be the ESI. PI crabs had the highest ESI and there was no significant 

difference among crabs from the other locations (Table 1). The small sample size of the PI crabs 

made comparison with crabs from other locations problematic. 

The weight of the hepatopancreas followed the same pattern as noted with whole weight, 

smallest for crabs from BB and largest in crabs from KI (Table 1). Accordingly, no significant 

differences were seen in the HSI values among the crab from different locations. The weight of 

ovaries was smallest for the crabs from BB and largest for crabs from KI and PB (Table 1). 

Crabs from PI had ovaries with weights between these two groups. GSI values followed the 

same pattern.
Table 1. Mean and SD of CL, whole weight, egg clutch weight, ESI, hepatopancreas weight, HSI, ovary weight, and GSI o

different locations. N = number of crab from each location. The superscript letters (A, B, C) indicate means sharing 

not significantly different from each other, p > 0.05. 

Location Date Value CL (mm) 

Whole 

weight (g) 

Clutch 

weight (g) ESI 

Hepatopancreas 

weight (g) HSI 

O

we

Mean 106.9 A 914 A 71.3 A 7.8 A 48.5 A 5.3 A SD ±6.2 ±157 ±14.3 ±1.0 ±15.5 ±1.5 

Bristol Bay 

June 2006 

N 10 10 10 10 10 10 

Mean 154.5 B 1,960 B, C 226.5 C 12.3 B 85.1 B, C 4.4 A 

SD ±3.5 ±665 ±7.8 ±4.6 ±18.0 ±0.6 

Pribilof Islands 

June 2006 

N 2 2 2 2 2 2 

Mean 141.0 B 2,137 C 180.0 C 8.4 A 108.2 C 5.0 A 

SD ±9.4 ±256 ±26.0 ±0.4 ±29.8 ±1.0 ±

Kodiak Island 

Sept. 2006 

N 4 4 4 4 4 4 

Mean 142.8 B 1,711 B 148.2 B 8.6 A 82.2 A 4.9 A 

SD ±10.7 ±291 ±34.3 ±1.1 ±25.1 ±0.5 ±

Petrel Bank 

Nov. 2006 

N 11 11 11 11 3 3 

6
To determine whether there was any relationship among biometric parameters, 

correlation coefficients were determined. CL and whole weight were positively correlated with 

weights of organs and weights of organs were correlated with each other (Table 2). Of the three 

indexes, only GSI had a significant correlation with CL, whole weight, hepatopancreas weight, 

and ovary weight. None of the three indexes were correlated with each other. 

Hepatopancreas Biochemistry 

A nested ANOVA treatment of the hepatopancreas moisture data indicated significant 

differences existed between locations and among replicates within the same location 

(Table 3). For ash content, the variation among crab within locations was significant but there 

were no significant differences among locations. The lipids results were similar to that noted for 

moisture content, as both location and replicates within location were a significant source of 

variance. The moisture content of the hepatopancreas of crabs from KI was lower than that seen 

in crabs from BB and PI but was not statistically different in the PB crabs (Table 4). As 

Table 2. Number of samples (N) and probability (p) of correlation coefficient (R) of CL, whole weight, 

egg weight, hepatopancreas weight, ovary weight, ESI, GSI, and HSI of red king crab. 

Whole 

weight 

Egg 

weight 

Hepatopancreas

weight 

Ovary 

weight ESI GSI HSI 

R 0.895 0.920 0.579 0.829 0.457 0.723 –0.465 

N 27 27 27 25 27 25 27 

CL 

p >0.001 >0.001 0.002 >0.001 0.016 >0.001 0.014 

R 0.894 0.791 0.848 0.208 0.663 –0.307 

N 27 27 25 27 25 27 

Whole 

weight 

p >0.001 >0.001 >0.001 0.297 >0.001 0.120 

R 0.694 0.745 0.619 0.591 –0.296 

N 27 25 27 25 27 

Egg 

weight 

p >0.001 >0.001 0.001 0.002 0.134 

R 0.725 0.134 0.533 0.303 

N 25 27 25 27 

Hepatopancreas 

weight p >0.001 0.506 0.006 0.124 

R 0.162 0.939 –0.250 

N 25 25 25 

Ovary 

weight 

p 0.440 >0.001 0.229 

R 0.152 –0.113 

N 25 27 

ESI 

p 0.467 0.573 

R –0.263 

N 25 

GSI 

p 0.204 

7
Table 3. Nested ANOVA of red king crab hepatopancreas composition where location replicates (Rep) 

are nested within location. 

Source dfa SSb MSc Fd p 

Moisture Location 3 758.23 252.740 7.19 <0.050 

Rep (location) 15 527.10 35.140 237.88 <0.001 

Error 19 2.81 0.148 

Ash Location 3 68.51 22.840 1.25 NSe

Rep (location) 15 273.32 18.220 7.54 <0.001 

Error 19 45.95 2.418 

Lipid Location 3 1,639.40 546.470 7.88 <0.050 

Rep (location) 15 1,040.10 63.940 157.45 <0.001 

Error 19 8.37 0.440 a df = degrees of freedom. d F = F-distribution value. 

b SS = sum of squares. e NS = not significant, p > 0.05. c MS = mean square. 

indicated by the nested ANOVA results, the variation of the hepatopancreas ash values due to 

location was not significant. Lipid contents of the hepatopancreas of crabs from BB and PI were 

significantly lower than that found in crabs from KI and PB. Hepatopancreas protein content 

was lower in crabs from KI than crabs from BB and PI. Moisture content of the hepatopancreas 

had a significant positive correlation with ash content and a significant negative correlation with 

lipid content (Table 5). Hepatopancreas moisture content was also negatively correlated with 

whole weight, hepatopancreas weight, ovary weight, and GSI. Ash content of the 

hepatopancreas was negatively correlated with lipid content, hepatopancreas weight, and HSI. 

Lipid content of the hepatopancreas had a positive correlation with hepatopancreas weight, ovary 

weight, and GSI. 

Ovary Biochemistry 

For ovary samples, variation due to location and replicate crab within location were 

significant for moisture and for lipid content (Table 6). For the ash content of the ovary samples, 

only variation due to location was statistically significant. The ovaries of crabs from PI had a 

higher moisture and ash content than seen in crabs from the other locations (Table 4). The 

ovaries of crabs from KI and PB had lower moisture and ash content than crabs from BB. Lipid 

content of ovaries was lower in the crabs from BB and PI than in crabs from KI and PB. Protein 

content of ovaries from PI crabs was greater than that in crabs from KI. 

As seen in the hepatopancreas results, ovarian moisture content was positively correlated 

with ash content but negatively correlated with lipid content (Table 7). Ovarian moisture content 

was not correlated with CL and whole-weight measurements of the size of the crab. Ovarian 

moisture content was negatively correlated with hepatopancreas weight, ovarian weight, and 

GSI. Ovarian ash content was negatively correlated with lipid content, ovary weight, and GSI. 

Lipid content of the ovary was positively correlated with hepatopancreas weight, ovary weight, 

and GSI. 

8
Table 4. Mean and SD of proximate composition of hepatopancreas and ovary tissue of red king crab 

from different locations. Ash, lipid, and protein values were adjusted to a dry basis; N = number 

of replicates from each location. The superscript letters (A, B, C) indicate means sharing a common 

letter were not significantly different from each other, p > 0.05. 

Location Date Value Moisture Ash Lipid Protein 

Hepatopancreas 

Mean 78.2 A 10.0 A 20.8 A 53.1 A

SD ±5.2 ±3.8 ±7.2 ±6.0 

Bristol Bay June 2006 

N 10 10 10 10 

Mean 81.0 A 11.4 A 16.4 A 58.7 A

SD ±2.7 ±0.0 ±5.3 ±4.0 

Pribilof Islands June 2006 

N 2 2 2 2 

Mean 67.9 B 7.7 A 34.7 B 40.2 B

SD ±1.4 ±1.1 ±2.3 ±2.1 

Kodiak Island Sept. 2006 

N 4 4 4 4 

Mean 73.0 A, B 7.3 A 31.4 B

SD ±1.2 ±0.2 ±1.8 

Petrel Bank Nov. 2006 

N 3 3 3 

— 

Ovary 

Mean 77.8 B 8.1 B 11.9 A

SD ±1.9 ±1.4 ±4.7 

Bristol Bay June 2006 

N 5 5 5 

— 

Mean 82.0 C 13.0 C 13.0 A 76.2 A

SD ±0.3 ±0.7 ±4.3 ±2.1 

Pribilof Islands June 2006 

N 2 2 2 2 

Mean 57.0 A 3.3 A 27.2 B 63.6 B

SD ±2.5 ±1.2 ±1.0 ±1.3 

Kodiak Island Sept. 2006 

N 4 4 4 4 

Mean 56.5 A 4.0 A 28.3 B

SD ±2.3 ±0.5 ±0.9 

Petrel Bank Nov. 2006 

N 3 3 3 

— 

Eggs 

Mean 58.7 A 5.5 A 30.8 B 60.2 A

SD ±2.0 ±1.2 ±0.9 ±2.9 

 Bristol Bay June 2006 

N 10 10 10 10 

Mean 61.2 A 3.9 A 30.2 A, B 62.3 A, B

SD ±0.1 ±0.1 ±0.1 ±0.1 

 Pribilof Islands June 2006 

N 2 2 2 2 

Mean 66.9 B 5.2 A 33.7 C 66.0 B

SD ±1.2 ±0.3 ±2.4 ±2.0 

 Kodiak Island Sept. 2006 

N 4 4 4 4 

Mean 68.8 B 5.5 A 28.9 A — 

SD ±1.6 ±0.6 ±1.6 

 Petrel Bank Nov. 2006 

N 11 11 11 

9
Table 5. Correlation coefficient (R) and associated probability (p) of hepatopancreas moisture, ash, and 

lipid content with CL, whole weight, egg weight, hepatopancreas weight, ovary weight, ESI, GSI, 

and HSI. Number of replicates was 19. 

Moisture Ash Lipid 

R p R p R p 

Ash 0.804 <0.001 

Lipid –0.763 <0.001 –0.558 0.013 

CL –0.342 0.151 –0.189 0.439 0.268 0.267 

Whole weight –0.458 0.049 –0.257 0.288 0.374 0.115 

Egg weight –0.314 0.191 –0.135 0.583 0.236 0.332 

Hepatopancreas 

weight 

–0.591 0.008 –0.469 0.043 0.527 0.021 

Ovary weight –0.607 0.006 –0.390 0.099 0.617 0.005 

ESI 0.084 0.731 0.139 0.57 –0.145 0.553 

GSI –0.612 0.005 –0.414 0.078 0.667 0.002 

HSI –0.308 0.200 –0.515 0.024 0.302 0.209 

Table 6. Nested ANOVA of red king crab ovary composition where location replicates (Rep) are nested 

within location. 

Source dfa SSa MSa Fa p 

Location 3 2,379.12 793.04 72.93 <0.001 

Rep (location) 9 97.87 10.87 95.00 <0.001 

Moisture 

Error 13 1.49 0.11 

Location 3 275.71 91.90 47.70 <0.001 

Rep (location) 8 15.41 1.93 1.04 NSb

Ash 

Error 11 20.43 1.86 

Location 3 1,534.26 511.42 25.38 <0.001 

Rep (location) 9 181.32 20.15 4.09 <0.050 

Lipid 

Error 13 64.02 4.92 a See Table 3 for definition of abbreviations. 

b NS = not significant, p > 0.05. 

Eggs Biochemistry 

Variation among different locations and variation among replicate crab within location 

were both significant for moisture and lipid content of red king crab eggs (Table 8). For the ash 

content of the egg samples, only the variation among replicates within location was statistically 

significant. Moisture content of eggs of BB and PI crabs was lower than that noted for crabs 

from KI and PB (Table 4). As noted in the hepatopancreas samples, ash content was not affected 

by location. The eggs of crabs from KI had a higher lipid content than the eggs of crabs from the 

other locations. The eggs of crabs from BB and PI had similar lipid content. Eggs from PB 

crabs had less lipid than crabs from BB, but there was no significant difference in the egg lipid 

content between crabs from PI and PB. 

10
Table 7. Correlation coefficient (R) and associated probability (p) of red king crab ovary moisture, ash, 

and lipid content with CL, whole weight, egg weight, hepatopancreas weight, ovary weight, ESI, 

GSI, and HSI. 

Moisture Ash Lipid 

R N* p R N p R N p 

Ash 0.902 13 >0.001 

Lipid –0.941 13 >0.001 –0.771 12 0.003 

CL –0.299 14 0.299 0.017 13 0.957 0.335 13 0.263 

Whole weight –0.489 14 0.076 –0.225 13 0.459 0.580 13 0.038 

Egg weight –0.214 14 0.463 0.103 13 0.738 0.254 13 0.402 

Hepatopancreas 

weight 

–0.538 14 0.047 –0.313 13 0.297 0.637 13 0.019 

Ovary weight –0.817 14 >0.001 –0.595 13 0.032 0.805 13 0.001 

ESI 0.335 14 0.241 0.533 13 0.061 –0.438 13 0.134 

GSI –0.881 14 >0.001 –0.657 13 0.015 0.824 13 0.001 

HSI –0.091 14 0.756 –0.230 13 0.449 0.1739 13 0.570 

*N = number of samples for each correlation. 

Table 8. Nested ANOVA of red king crab egg composition where location replicates (Rep) are nested 

within location. 

Source dfa SSa MSa Fa p 

Moisture Location 3 1,155.35 385.12 67.73 <0.001 

Rep (location) 23 130.78 5.69 46.37 <0.001 

Error 26 3.19 0.12 

Ash Location 3 10.15 3.38 2.38 NSb

Rep (location) 23 32.72 1.42 4.60 <0.001 

Error 26 8.05 0.31 

Lipid Location 3 137.63 45.88 10.65 <0.001 

Rep (location) 23 99.11 4.31 5.01 <0.001 

Error 27 23.23 0.86 a See Table 3 for definition of abbreviations. 

b NS = not significant, p > 0.05. 

Unlike the hepatopancreas and ovarian tissue, the moisture content of red king crab eggs 

was not significantly correlated with either ash or lipid content (Table 9). Moisture content was 

positively correlated with CL and whole weight, indicating that the eggs from larger crabs were 

higher in moisture content. Moisture content was also positively correlated with egg weight, 

hepatopancreas weight, ovary weight, and GSI. Moisture content of the eggs was negatively 

correlated with HSI. Ash content was correlated only with ESI and that correlation coefficient 

was negative. 

11
Table 9. Correlation coefficient (R) and associated probability (p) of red king crab egg moisture, ash, and 

lipid content with CL, whole weight, egg weight, hepatopancreas weight, ovary weight, ESI, GSI, 

and HSI. 

Moisture Ash Lipid 

R N* p R N p R N p 

Ash 0.069 27 0.733 

Lipid –0.254 27 0.201 –0.143 27 0.478 

CL 0.724 27 <0.001 –0.258 27 0.194 –0.192 27 0.337 

Whole weight 0.669 27 <0.001 –0.205 27 0.306 0.063 27 0.755 

Egg weight 0.582 27 0.001 –0.345 27 0.078 0.040 27 0.841 

Hepatopancreas 

weight 

0.406 27 0.036 –0.164 27 0.414 0.244 27 0.219 

Ovary weight 0.884 25 <0.001 –0.042 25 0.842 –0.080 25 0.704 

ESI 0.110 27 0.586 –0.463 27 0.015 –0.025 27 0.904 

GSI 0.913 25 <0.001 –0.015 25 0.943 –0.212 25 0.308 

HSI –0.391 27 0.044 0.075 27 0.711 0.235 27 0.239 

*N = number of samples for each correlation. 

12
Discussion 

While it would have been preferable to have all crab with the same shell condition and 

clutch size and to be able to determine the stage of egg development, some interesting 

comparisons can still be made. The stage in the reproductive cycle of crab from each area 

relative to the others can be reasonably estimated using the GSI values as it typically increases 

throughout the seasonal reproductive cycle of crustaceans. Somerton and MacIntosh (1985) 

reported that mean GSI values increased from about 1.0 to 8.0 during the biannual reproduction 

cycle of blue king crab (Paralithodes platypus) from PI. The range of GSI values was greater in 

their study as their samples were taken over a greater portion of the reproductive cycle than the 

limited time range of this study. Accordingly, crabs from BB and PI were earlier in their yearly 

reproduction cycle than crabs from KI and PB based on the GSI values. This would be 

consistent with observations of others based on the dates the samples were taken and the typical 

times for mating for the crab in the different areas of this study. 

Mating for red king crab in Bristol Bay can occur anytime from January to June (Otto et 

al. 1990, Stevens and Swiney 2007). Mating for red king crabs in Kodiak waters usually occurs 

primarily in April and May (Powell et al. 2002). The relative ranking of the reproductive stage 

of the crab in this study based on GSI values is also similar to that based on shell codes. Female 

king crab molt before mating; therefore, specimens with low shell codes have likely molted more 

recently than ones with higher shell codes. Although the crabs from PI had a higher mean ESI 

value than crab from other areas, it would be unwarranted to draw any conclusions based on such 

a small sample size of crabs from PI. A crab with a higher ESI value could mean it was further 

along in the reproductive cycle. 

The lack of any significant differences in HSI values among crab from different locations 

could be interpreted as indicating the crab were equally recovered from the hatching, molting, 

and mating process, but this may be unwarranted based on the limited number of crabs from the 

PI and KI areas. Turner et al. (2003) noted that the caloric content of hepatopancreas and 

reproductive organs of blue crab (Callinectes sapidus) increases linearly with time after molting 

once muscle caloric content has reached a threshold value. The lack of sampling throughout the 

reproductive cycle for crab in any of the areas of this study precluded the sort of analysis used by 

Turner et al. (2003), but the expectation is that a similar process is likely to occur in red king 

crab. The positive correlations among CL, whole weight, and weight of organs were what would 

be expected, as larger individuals should have larger organs. The lack of any significant 

correlation among ESI, HSI, and GSI may indicate that the change in weight of these tissues 

relative to whole weight occurred independently of each other at least during the limited portion 

of the reproductive cycle sampled in this study. 

In most cases, differences in the biochemical composition, especially lipid content, of the 

hepatopancreas and ovary of crab from different locations followed the pattern that would be 

expected given the likely differences in time between typical mating season and capture date. 

The higher lipid content in the hepatopancreas and ovary of crabs from KI and PB was likely due 

13
14

to having more time to recover from molting and mating. Decreasing moisture content and 

increasing lipid content of ovaries during the reproductive cycle have been noted with other 

crustaceans (Teshima and Kanazawa 1983, Lautier and Lagarrigue 1988, Mourente et al. 1994, 

Wouters et al. 2001, Reppond et al. 2009). The lower ovarian ash content of crabs from KI and 

PB may be due to the dilution effect of increasing lipid content. Some of the difference among 

samples could be due to location alone, however. 

Increasing moisture content and decreasing lipid content during embryonic development 

have been reported for several crab species (Petersen and Anger 1997, Gardner 2001, Reppond et 

al. 2008). The higher moisture content in eggs of crabs from KI and PB is consistent with the 

likelihood that crabs from these locations were further along in the seasonal sexual development 

than crabs from BB or PI. Differences among the lipid values were not consistent with the likely 

differences in time since mating, however, as KI crab eggs had the highest lipid content. A 

lower lipid value in the eggs would be expected in more mature eggs if lipids were the main 

energy source of developing red king crab embryos. While it was not possible to determine the 

stage of embryonic development for these samples, as the samples were frozen at sea, it is 

unlikely that eggs from crabs from Kodiak were less mature than eggs of crabs from other 

locations given the GSI and egg moisture values. Therefore, the higher lipid content of KI crab 

eggs is likely the result of more lipid being deposited in the developing oocytes prior to mating. 

The negative correlation between the moisture content of the hepatopancreas with 

hepatopancreas weight and GSI indicates that the moisture content of the hepatopancreas 

decreased as the crab proceeded through the reproductive cycle. Similarly, the positive 

correlation of the lipid content of the hepatopancreas with GSI indicates that a net increase in 

lipid was occurring as the crab progressed during the reproductive cycle. The negative 

correlation of ovarian moisture and ash content with GSI indicates that the ovary was decreasing 

in moisture and ash as the crab proceeded through the reproductive cycle. The positive 

correlation of ovarian lipid content with GSI indicates that lipid was being deposited as the 

ovaries matured. The positive correlation of egg moisture values with GSI indicates that 

moisture should increase during seasonal development. 

The positive correlation of egg moisture content with both hepatopancreas weight and 

ovarian weight can be explained by the fact that both organs are likely to increase in size during 

the reproductive cycle during which time the moisture content of the eggs is also increasing. 

Somewhat surprising was the lack of a significant negative correlation between egg lipid content 

and GSI or any other parameters studied. This could be the result of the limited embryonic 

development time range between the samples. In fact, the range in egg lipid values among the 

samples was much smaller than the ranges in hepatopancreas or ovary lipid values. In other 

words, change in egg lipid values was less than changes in hepatopancreas and ovary lipid values 

over the developmental time covered by the samples in this study. These results could change if 

more samples were taken later in the seasonal development. 

The results of this preliminary study indicate that a more extensive experiment, in which 

crab would be taken from the same area throughout the yearly cycle, would greatly benefit our 

understanding of the biochemical changes associated with reproduction. It would also prove 

beneficial in the future to take samples from the same regions at the same time of year in order to 

see if there is a year-to-year variation in the nutritional status of red king crab.
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