Hostname: page-component-74656f9884-2dmjx Total loading time: 0 Render date: 2026-11-06T13:15:46.561Z Has data issue: false hasContentIssue false
  • English
  • Français

Egg volume, energy content and fatty acid profile of Maja brachydactyla (Crustacea: Brachyura: Majidae) during embryogenesis

Published online by Cambridge University Press:  08 July 2008

Joana Figueiredo  and
Luís Narciso
Joana Figueiredo*
Affiliation:
Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, Avenida Nossa Senhora do Cabo, 939 2750–374 Cascais, Portugal
Luís Narciso
Affiliation:
Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, Avenida Nossa Senhora do Cabo, 939 2750–374 Cascais, Portugal
*
Correspondence should be addressed to: Joana Figueiredo, Laboratório Marítimo da Guia, Centro de Oceanografia, Faculdade de Ciências da Universidade de Lisboa, Avenida Nossa Senhora do Cabo, 939, 2750–374 CascaisPortugal email: joana_figueiredo@portugalmail.pt
Rights & Permissions [Opens in a new window]

Abstract

Fatty-acid and energy content of Maja brachydactyla eggs at different developmental stages (recently spawned, half-developed and ready to hatch) were analysed in order to understand what is being consumed and produced during the embryonic development. Egg volume increased during development (34%, 0.187 to 0.285 mm3, N = 270) and was negatively correlated with egg energy and fatty-acid content (r = −0.80 and r = −0.46, respectively), which decreased through embryogenesis. The most consumed fatty acids were the PUFA (21.2 μg · mg dw−1), followed by the SFA (18.8 μg · mg dw−1) and MUFA (14.9 μg · mg dw−1). Palmitic (16:0), oleic (18:1n-9) and eicosapentaenoic (EPA, 20:5n-3) acids were preferentially consumed (13.14, 9.21 and 8.67 μg · mg dw−1, respectively). The fatty acid composition found in M. brachydactyla eggs reflected the habitat and omnivorous and detritivorous scanvenger diet of the adults, although the consumption of algae was more important than previously thought, at least in the area where these adults were captured. Pre-hatching eggs have a high PUFA content (64.5 μg · mg dw−1 or 46.3% of the egg fatty-acid content). We conclude that larvae of this species might need a diet rich in PUFA, particularly EPA and DHA, for successful development. From the culture perspective, live preys commonly used in aquaculture will likely require to be enriched with DHA.

Keywords

crabdevelopmentecologyfatty acidlarval dietreproduction

Information

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 88 , Issue 7 , November 2008 , pp. 1401 - 1405
Copyright
Copyright © Marine Biological Association of the United Kingdom 2008

INTRODUCTION

Spider crabs Maja brachydactyla Balss, 1922 are important seafood items, with commercial fisheries occurring in all distribution areas—coastal shores of the North Sea to the north of Africa (Kergarion, Reference Kergarion1984; Neumann, Reference Neumann1998). Females mature and spawn from March to September (González-Gurriarán et al., Reference González-Gurriarán, Fernández, Freire and Muiño1998). Since M. brachydactyla has a high market price and is overexploited (Kergarion, Reference Kergarion1984; Ellis et al., Reference Ellis, Rogers and Freeman2000), it is important to develop a culture protocol to produce high quality animals that could compete with wild caught individuals, thus reducing exploitation of wild stocks. Larval culture is one of the most critical phases for aquaculture, particularly developing appropriate larval diets that can fulfil the requirements for a proper larval development. In aquaculture, the egg biochemical composition of many marine species has been used as a reference for the formulation of larval diets. A diet with a composition similar to the eggs should be adequate to the larvae after the onset of exogenous feeding (Rainuzzo et al., Reference Rainuzzo, Reitan and Olsen1997; Narciso & Morais, Reference Narciso and Morais2001).

The egg plays a central role in the life history of marine invertebrates and must contain all nutrients required for maintenance and development of the embryo (Anger, Reference Anger1998; Rosa et al., Reference Rosa, Calado, Narciso and Nunes2007). Lipids generally provide ~60% of the total energy expenditure of the developing crustacean embryo (Herring, Reference Herring1974; Holland, Reference Holland, Malins and Sargent1978; Amsler & George, Reference Amsler and George1984) and are utilized as structural components of cell membranes (Rosa & Nunes, Reference Rosa and Nunes2003). Previous studies revealed that the fatty-acid content and their dynamics during embryogenesis provide information on crustacean life history traits, feeding ecology and habitats (Rosa et al., Reference Rosa, Calado, Narciso and Nunes2007). Essential long-chain poly-unsaturated fatty acids (PUFA) cannot be synthesized de novo and are utilized as energy only when available in excess (Anger, Reference Anger1998). A low level of essential PUFA in the diet affects the reproductive performance of adult females by reducing embryo viability. The effect should likewise decrease the physiological condition of freshly hatched larvae and reduce development, survival and growth (Anger, Reference Anger1998).

We aim to study egg volume, energy content, and fatty-acid profile during the embryonic development of M. brachydactyla, and its potential implications for aquaculture.

MATERIALS AND METHODS

Sampling

Ovigerous females of Maja brachydactyla were purchased at local markets in Cascais, Portugal during April and May 2005. Live crabs were transported to the laboratory and female carapace length (CL) and carapace width (CW) were measured. The embryonic developmental stage of all female broods were classified according to the following criteria: stage I—eggs with uniformly distributed yolk (orange), absence of cleavage and eyes, no visible blastoderm; stage II—distinct blastoderm with half yolk, eyes visible; and stage III—embryos in an advanced stage of development (large eyes) with little or no yolk.

Egg volume

Six females were selected for each developmental stage to study egg size. Thirty eggs were taken from each female and their diameters (D) were measured in salt water immersion (30 eggs/female of six females for each developmental stage, N = 540) to the nearest 0.01 mm under a steromicroscope (Olympus®, model SZ6045TR) with a calibrated eyepiece. Egg volume was calculated using the formula V= (π D3)/6 for spheroid embryos.

Egg energy content

In order to assess egg energy content throughout embryonic development, three broods per embryonic stage were randomly sampled (N = 9). After freeze-drying the samples for 24 hours with a Savant Vapornet VN100 Freeze Dryer, the energy content (cal. g dw−1) of each sample was measured with a Parr-1425 Semimicro Oxygen Bomb calorimeter (previously calibrated with benzoic acid). Samples (62 to 143 mg) were burned in oxygen in the calorimeter.

Egg fatty-acid profile

To determine the fatty-acid profile of M. brachydactyla eggs at each developmental stage, nine egg masses per embryonic stage were sampled (N = 27). After freeze-drying, the samples were ground in a Potter homogenizer with chloroform–methanol–water (2:2:1.8) (Bligh & Dyer, Reference Bligh and Dyer1959). An internal standard fatty acid (C19:0) was added to the extracts. After saponification and esterification of the lipid extracts (Metcalfe & Schmitz, Reference Metcalfe and Schmitz1961), the fatty-acid methyl esters (FAME) were injected into capillary columns (30 m fused silica, 0.32 I.D.) installed in a Varian Star 3400CX gas–liquid chromatograph (GLC). Helium was used as carrier gas at a flow rate of 1 ml/minute; oven temperature was 180ºC for 7 minutes, then 200ºC (with a temperature gradient of 4ºC/minute) over a period of 71 minutes. Both the injector and the FID detector were set at 250ºC. GLC data acquisition and handling were performed using a Varian integrator 4290 connected to the GLC. Peak quantification was carried out with a Star Chromatography workstation installed in an IBM PS/1. Peak identification was performed using cod liver oil chromatograms as a reference.

Data analysis

One way ANOVAs were used to test if there were significant differences in egg volume, energy content, total fatty acid content and the fatty acid content between eggs in different developmental stages. Post-hoc Tukey's multiple comparisons tests were performed if a significant difference was found. The correlations between egg volume and energy content, and egg volume and total FA content were tested using non-parametric Spearman correlation-coefficients. All statistical analyses were performed in Statistica 7.0 with a significance level of 0.05.

RESULTS AND DISCUSSION

Ovigerous females collected ranged from 115.44 to 136.19 mm CW (130.68 to 152 mm CL). Average egg diameters were 0.707 mm (SE = 0.002, N = 180) for stage I, 0.782 mm (SE = 0.003, N = 180) for stage II, and 0.816 mm (SE = 0.002, N = 180) for stage III. Comparisons of egg volume, energy content, total fatty-acid content and per cent fatty-acid content among the developmental stages, are shown in Table 1. The egg diameter observed in the present study (0.71–0.82 mm, Table 1) was greater than what is usually reported for marine and brackish water species (0.25 and 0.45 mm) (Anger, Reference Anger1995). However, while in decapod crustaceans we commonly observe a 50–150% egg volume increase during development (Wear, Reference Wear1974; Petersen & Anger, Reference Petersen and Anger1997; Oh & Hartnoll, Reference Oh and Hartnoll1999), in Maja brachydactyla egg volume only increased 34%. Greater egg volume increase was recorded in the earlier development, similar to what was observed by De Vries & Forward (Reference De Vries and Forward1991) in other brachyurans. Like in other decapod species (e.g. Nauticaris magellanica, Wehrtmann & Kattner, Reference Wehrtmann and Kattner1998), both egg energy content and fatty acids were negatively correlated with egg volume increase (N = 9, r = −0.80, t = −3.54, P < 0.01 and N = 27, r = −0.46, t = −2.39, P < 0.03, respectively) showing that M. brachydactyla consumed significant amounts of energy (9.58%), particularly, fatty acids (28.58%) during embryonic development. This might be due to the fact that lipids are the major energy source for the development (Clarke et al., Reference Clarke, Brown and Holmes1990).

Table 1.

Egg diameter (mm), volume (mm3), energy content (cal. g dw−1), FA content (µg · mg dw−1) (average±SE), per cent increase from stage I to stage III (if significant) and F and P value results of the one-way-ANOVA comparing different embryonic stages of development (df = 2). Different superscript letters represent significant differences between embryonic stages (Tukey post-hoc tests) (FA, fatty acid; SFA, saturated fatty acid; MUFA, monounsaturated fatty acid; PUFA, polyunsaturated fatty acid).

However, the relatively high fatty-acid content of pre-hatching eggs indicates larvae might display a certain degree of independence from external food sources (planktontrophy) (Staton & Sulkin, Reference Staton and Sulkin1991; Leme, Reference Leme2006; Rosa et al., Reference Rosa, Calado, Narciso and Nunes2007); this is in agreement with the results obtained by Urcera et al. (Reference Urcera, Anaiz, Rua and Coo1993) who studied the effect of starvation during early larval development of M. brachydactyla: if not fed, newly hatched larvae survived for a maximum of 6 days but only 10% of the larvae metamorphosed to zoea II. The fatty-acid composition of M. brachydactyla eggs was similar to that of other decapod species (Wehrtmann & Kattner, Reference Wehrtmann and Kattner1998; Narciso & Morais, Reference Narciso and Morais2001; Rosa et al., Reference Rosa, Calado, Narciso and Nunes2007); with some variation expected, as fatty-acid content varies between and within species according to the adults' diet and habitat (Cahu et al., Reference Cahu, Fauvel and Aquacop1986; Wehrtmann & Kattner, Reference Wehrtmann and Kattner1998; Rosa et al., Reference Rosa, Calado, Narciso and Nunes2007).

The major saturated fatty acids (SFA) in M. brachydactyla eggs were palmitic (16:0), stearic (18:0) and 17:0 acids. The other SFA detected at lower levels were 12:0, 13:0, 14:0, 15:0, 20:0 and 22:0. SFA were significantly consumed through embryogenesis (37.3%), particularly14:0, 16:0, 17:0, 18:0 and 22:0 while, the other remained stable throughout embryogenesis, except 13:0 that was initially synthesized, but consumed at the posterior. Odd-numbered fatty acids (particularly 15:0 and 17:0) are known to be largely biosynthesized by marine heterotrophic bacteria, which are particularly abundant in sediment (Volkman et al., Reference Volkman, Barrett, Blackburn, Mansour, Sikes and Gelin1998). The high proportion of odd-numbered fatty acids (above 3%) in M. brachydactyla eggs reveals the detritivore scavenger nature common to crab species.

All branched fatty acids (BFA) (Iso 15:0, Anteiso 15:0, Iso 16:0, Anteiso 16:0 and Iso 17:0) were detected in low amounts. Fourteen per cent of the BFA were consumed through embryogenesis: Iso 16:0 and Anteiso 16:0 decreased significantly; Anteiso 15:0 and Iso 17:0 remained stable; and Iso 15:0 increased significantly (Table 1). The dominant monounsaturated fatty acids (MUFA) were 18:1n-9, palmitoleic (16:1n-7) and vaccenic (18:1n-7) acids. The other MUFA detected included 14:1n-5, 16:1n-9, 16:1n-5, 17:1n-8, 18:1n-5, 19:1n-8, 19:1n-10, 20:1n-9, 20:1n-7, 20:1n-5, 22:1n-11, 22:1n-9 and 22:1n-7. Twenty-seven per cent of the MUFA were consumed during embryonic development: 14:1n-5, 16:1n-7, 17:1n-8, 18:1n-7, 18:1n-9, 22:1n-11 and 22:1n-7 were significantly consumed through embryogenesis, while 20:1n-9 were synthesized (172% increase) and the others remained stable (Table 1). The fatty acid 18:1n-9 is the major fatty acid in marine animals and a general marker for carnivory (Dalsgaard et al., Reference Dalsgaard, St John, Kattner, Müller-Navarra and Hagen2003). The medium–high ratio of 18:1n-7/18:1n-9 and low percentage of 18:1n-9 (8.7–11%) shows that this species, at least in the area the animals were captured, is less carnivorous than what has been previously described (Bernárdez et al., Reference Bernárdez, Freire and González-Gurriarán2000); Kergarion (Reference Kergarion1974) previously described that the feeding regime of Maja changed depending on where the animals are caught, as it would be expected of an omnivorous species with a large distribution.

The most prevalent PUFA was eicosapentaenoic acid (EPA, 20:5n-3), followed by docosahexaenoic (DHA, 22:6n-3) and eicosatetraenoic (20:4n-3) acids. Additional PUFA detected were 16:4n-3, linoleic acid (18:2n-6), linolenic acid (18:3n-3), 18:4n-3, 20:3n-6, arachidonic acid (ARA, 20:4n-6), 20:3n-3, 20:4n-3, 21:5n-3, 22:4n-6, 22:5n-6 and docosapentaenoic acid (DPA, 22:5n-3). Twenty-four per cent of the PUFA were consumed during embryogenesis: all fatty acids decreased significantly, except 16:4n-3, 20:3n-6, 20:4n-3 and 22:4n-6 that remained stable (Table 1). The high proportion of essential PUFA of C18 and C20 (27–28.5%, particularly EPA), known trophic markers of primary producers (Rosa et al., Reference Rosa, Calado, Narciso and Nunes2007), reflects the adults' macroalgae-rich diet (namely laminar and coralline algae) (Kergarion, Reference Kergarion1984; Bernárdez et al., Reference Bernárdez, Freire and González-Gurriarán2000). The medium EPA/DHA ratio (1.14–1.37) indicates the species is in a medium level of the trophic chain (Auel et al., Reference Auel, Harjes, da Rocha, Stübing and Hagen2002; Scott et al., Reference Scott, Kwasniewski, Falk-Petersen and Sargent2002).

The Maja brachydactyla egg fatty-acid profile can provide clues to select the most adequate larval diet. The high content of PUFA, particularly EPA and DHA, indicates that larvae need a diet rich in these PUFA, as they are significantly consumed through embryogenesis (27.2% and 19.7%, respectively). The presently available preys for larval rearing in aquaculture, particularly Artemia, are great sources of EPA and therefore the supply of this fatty acid is usually not the major concern when rearing the larvae. DHA is considered one of the most important fatty acids in decapod eggs, generally accounting for 10–20% of the total fatty acids (Wehrtmann & Graeve, Reference Wehrtmann and Graeve1998; Rosa et al., Reference Rosa, Calado, Narciso and Nunes2007), however, rotifers and Artemia nauplii have naturally low PUFA content, particularly DHA (Narciso & Morais, Reference Narciso and Morais2001). Many studies have attempted to develop culture protocols for alternative prey items with improved fatty-acid profiles, such as copepods (Sørensen et al., Reference Sørensen, Drillet, Engell-Sørensen, Hansen and Ramløv2007). However, copepod culture remains unreliable as an alternative prey in the aquaculture industry, thus rotifers and Artemia nauplii are still the most commonly used live feed since they can be boosted with PUFA to fulfil larval requirements (Rainuzzo et al., Reference Rainuzzo, Reitan and Olsen1997; Sorgeloos et al., Reference Sorgeloos, Dhert and Candreva2001). This was observed in the two reported cultures of M. brachydactyla by Urcera et al. (Reference Urcera, Anaiz, Rua and Coo1993) and Andrés et al. (Reference Andrés, Estévez and Rotllant2007); newly hatched larvae fed Artemia nauplii, known to have low content of DHA (Narciso & Morais, Reference Narciso and Morais2001), yielded lower survival and growth (18% survival and 24 days of larval duration; Urcera et al., Reference Urcera, Anaiz, Rua and Coo1993) than enriched-Artemia nauplii (with PUFA, including DHA, through enrichment products and/or green water treatments) (46% in 22 days and 25.3% with faster development, respectively in Urcera et al., Reference Urcera, Anaiz, Rua and Coo1993 and Andrés et al., Reference Andrés, Estévez and Rotllant2007).

ACKNOWLEDGEMENTS

We thank Ana Pêgo, Filipa Faleiro, Junda Lin and Justin Anto for their technical support and valuable comments, and Fundação para a Ciência e Tecnologia for the PhD scholarship (SFRH/BD/17130/2004) to the first author.

References

REFERENCES

Amsler, M.O. and George, R.Y. (1984) Seasonal variation in the biochemical composition of the embryos of Callinectes sapidus Rathbun. Journal of Crustacean Biology 4, 546–553.CrossRefGoogle Scholar
Andrés, M., Estévez, A. and Rotllant, G. (2007) Growth, survival and biochemical composition of spider crab Maja brachydactyla (Balss, 1922) (Decapoda: Majidae) larvae reared under different stocking densities, prey:larva ratios and diets. Aquaculture 273, 494–502.CrossRefGoogle Scholar
Anger, K. (1995) The conquest of freshwater and land by marine crabs: adaptations in life-history patterns and larval bioenergetics. Journal of Experimental Marine Biology and Ecology 193, 119–145.Google Scholar
Anger, K. (1998) Patterns of growth and chemical composition in decapod crustacean larvae. Invertebrate Reproduction and Development 33, 159–176.Google Scholar
Auel, H., Harjes, M., da Rocha, R., Stübing, D. and Hagen, W. (2002) Lipid biomarkers indicate different ecological niches and trophic relationships of the Artic hyperiid amphipods Themisto abyssorum and T. libellula. Polar Biology 25, 374–383.CrossRefGoogle Scholar
Bernárdez, C., Freire, J. and González-Gurriarán, E. (2000) Feeding of the spider crab Maja squinado in rocky subtidal areas of the Ría de Arousa (north-west Spain). Journal of the Marine Biological Association of the United Kingdom 80, 95–102.CrossRefGoogle Scholar
Bligh, E.G. and Dyer, W.J. (1959) A rapid method of total lipids extraction and purification. Canadian Journal of Biochemistry and Physiology 37, 911–917.Google Scholar
Cahu, C., Fauvel, C. and Aquacop, (1986) Effect of food fatty acids composition of P. vannamei broodstock on egg quality. International Council for the Exploration of the Sea. Mariculture Committee 28, 1–8.Google Scholar
Clarke, A., Brown, J.H. and Holmes, L.J. (1990) The biochemical composition of eggs from Macrobrachium rosenbergii in relation to embryonic development. Comparative Biochemistry and Physiology—Part B 96, 505–511.Google Scholar
Dalsgaard, J., St John, M., Kattner, G., Müller-Navarra, D. and Hagen, W. (2003) Fatty acid trophic markers in the pelagic marine environment. Advances in Marine Biology 46, 225–340.CrossRefGoogle ScholarPubMed
De Vries, M.C. and Forward, R.B. Jr (1991) Mechanisms of crustacean egg hatching: evidence for enzyme release by crab embryos. Marine Biology 110, 281–291.Google Scholar
Ellis, J.R., Rogers, S.I. and Freeman, S.M. (2000) Demersal assemblages in the Irish Sea, St George's Channel and Bristol Channel. Estuarine, Coastal and Shelf Science 51, 299–315.CrossRefGoogle Scholar
González-Gurriarán, E., Fernández, L., Freire, J. and Muiño, R. (1998) Mating and role of seminal receptacles in the reproductive biology of the spider crab Maja squinado (Decapoda: Majidae). Journal of Experimental Marine Biology and Ecology 220, 269–285.CrossRefGoogle Scholar
Herring, P.J. (1974) Size, density and lipid content of some decapod eggs. Deep-Sea Research 21, 91–94.Google Scholar
Holland, D.L. (1978) Lipid reserves and energy metabolism in the larvae of benthic marine invertebrates. In Malins, D.C. and Sargent, J.R. (eds) Biochemical and biophysical perspectives in marine biology. London: Academic Press, pp. 85–123.Google Scholar
Kergarion, G. (1974) Régime alimentaire de Maia squinado. Conseil International pour l'Exploration de la Mer. Comité des crustacés, coquillages et benthos, CM1974/K:36, 6 pp.Google Scholar
Kergarion, G. (1984) L'araignée de mer, Maia squinado H., Biologie et exploitation. La Pêche Maritime 1279, 575–583.Google Scholar
Leme, M.H.A. (2006) Seasonal changes in reproductive traits of the crab Sesarma rectum (Grapsoidea: Sesarmidae) on the northern coast of São Paulo State, Brazil. Journal of Crustacean Biology 26, 141–147.Google Scholar
Metcalfe, L.D. and Schmitz, A.A. (1961) The rapid preparation of fatty acids esters for gass chromatography analysis. Analytical Chemistry 33, 363–364.CrossRefGoogle Scholar
Narciso, L. and Morais, S. (2001) Fatty acid profile of Palaemon serratum (Palaemonidae) eggs and larvae during embryonic and larval development using different live diets. Journal of Crustacean Biology 21, 566–574.CrossRefGoogle Scholar
Neumann, V. (1998) A review of the Maja squinado (Crustacea: Decapoda: Brachyura) species-complex with a key to the eastern Atlantic and Mediterranean species of the genus. Journal of Natural History 32, 1667–1684.Google Scholar
Oh, C. and Hartnoll, R.G. (1999) Brood loss during incubation in Philocheras trispinosus (Decapoda) in Port Erin Bay, Isle of Man. Journal of Crustacean Biology 19, 467–476.CrossRefGoogle Scholar
Petersen, S. and Anger, K. (1997) Chemical and physiological changes during embryonic development of the spider crab, Hyas araneus L. (Decapoda: Majidae). Comparative Biochemistry and Physiology—Part B 117, 299–306.CrossRefGoogle Scholar
Rainuzzo, J.R., Reitan, K.I. and Olsen, Y. (1997) The significance of lipids at early stages of marine fish: a review. Aquaculture 155, 103–116.CrossRefGoogle Scholar
Rosa, R. and Nunes, M.L. (2003) Tissue biochemical composition in relation to the reproductive cycle of deep-sea decapod Aristeus antennatus on the south Portuguese coast. Journal of the Marine Biological Association of the United Kingdom 83, 963–970.Google Scholar
Rosa, R., Calado, R., Narciso, L. and Nunes, M.L. (2007) Embryogenesis of decapod crustaceans with different life history traits, feeding ecologies and habitats: a fatty acid approach. Marine Biology 151, 935–947.CrossRefGoogle Scholar
Scott, C., Kwasniewski, S., Falk-Petersen, S. and Sargent, J.R. (2002) Species differences, origins and functions of fatty acids in the wax esters and phospholipids of Calanus hyperboreus, C. glacialis and C. finmarchicus from Artic waters. Marine Ecology Progress Series 235, 127–134.CrossRefGoogle Scholar
Sørensen, T.F., Drillet, G., Engell-Sørensen, K., Hansen, B.W. and Ramløv, H. (2007) Production and biochemical composition of eggs from neritic calanoid copepods reared in large outdoor tanks (Limfjord, Denmark). Aquaculture 263, 84–96.Google Scholar
Sorgeloos, P., Dhert, P. and Candreva, P. (2001) Use of the brine shrimp, Artemia spp., in marine fish larviculture. Aquaculture 200, 147–159.CrossRefGoogle Scholar
Staton, J.L. and Sulkin, S.D. (1991) Nutritional requirements and starvation resistance in larvae of the brachyuran crabs Sesarma cinereum (Bosc) and S. reticulatum (Say). Journal of Experimental Marine Biology and Ecology 152, 271–284.Google Scholar
Urcera, M.J., Anaiz, R., Rua, N. and Coo, A. (1993) Cultivo de la centolla Maja squinado: Influenza de la dieta en el desarrollo larvario. Actas del IV Congreso Nacional de Acuicultura, Isla de Arosa, Spain, 269–274.Google Scholar
Volkman, J.K., Barrett, S.M., Blackburn, S.I., Mansour, M.P., Sikes, E.L. and Gelin, F. (1998) Microalgal biomarkers: a review of recent research developments. Organic Geochemistry 29, 1163–1179.CrossRefGoogle Scholar
Wear, R.G. (1974) Incubation in British decapod crustaceans, and the effect of temperature on the rate of success of embryonic development. Journal of the Marine Biological Association of the United Kingdom 54, 745–762.CrossRefGoogle Scholar
Wehrtmann, I.S. and Graeve, M. (1998) Lipid composition and utilization in developing eggs of two tropical marine caridean shrimps (Decapoda: Caridea: Alpheidae, Palaemonidae). Comparative Biochemistry and Physiology—Part B 121, 457–463.Google Scholar
Wehrtmann, I.S. and Kattner, G. (1998) Changes in volume, biomass, and fatty acids of developing eggs in Nauticaris magellanica (Decapoda: Caridea): a latitudinal comparison. Journal of Crustacean Biology 18, 413–422.Google Scholar
Figure 0

Table 1. Egg diameter (mm), volume (mm3), energy content (cal. g dw−1), FA content (µg · mg dw−1) (average±SE), per cent increase from stage I to stage III (if significant) and F and P value results of the one-way-ANOVA comparing different embryonic stages of development (df = 2). Different superscript letters represent significant differences between embryonic stages (Tukey post-hoc tests) (FA, fatty acid; SFA, saturated fatty acid; MUFA, monounsaturated fatty acid; PUFA, polyunsaturated fatty acid).