Fatty acids dynamics during embryonic development in genus Uca (Brachyura: Ocypodidae), from the mangroves of Inhaca Island, Mozambique Paulo Torres a, * , Gil Penha-Lopes a , Luı ´s Narciso a , Adriano Macia b , Jose ´ Paula a a Laborato ´rio Marı ´timo da Guia, Faculdade de Cie ˆncias da Universidade de Lisboa, Av. Nossa Sr. a do Cabo, n  939, 2750-374 Cascais, Portugal b Departamento de Cie ˆncias Biolo ´gicas, Faculdade de Cieˆncias, Universidade Eduardo Mondlane, C.P. 257 Maputo, Mozambique article info Article history: Received 15 January 2008 Accepted 23 July 2008 Available online 31 July 2008 Keywords: fatty acids embryonic development egg Uca metabolism mangrove Regional terms: East Africa Mozambique Inhaca Island (26  S 33  E) abstract Variations in egg volume and fatty acid (FA) content through embryogenesis were evaluated in Uca species from Inhaca island, Mozambique. Egg volume increased 96.1%, 93.3%, 84.2%, 92.9%, 96.3%, respectively, in Uca annulipes, Uca inversa, Uca urvillei, Uca chlorophthalmus and Uca vocans (p < 0.05). Fatty acid content decreased through embryogenesis, showing its importance as fuel during embryonic development. Major fatty acids were 16:0, 18:0, 16:1n-7, 18:1n-9, 18:1n-7, 18:2n-6, 20:5n-3 and 20:4n-3. Unsaturated fatty acids (UFA) and saturated fatty acids (SFA) were used up at a similar rate for U. annulipes and U. inversa contrarily to the other three species. Within the UFA, MUFA were more consumed than PUFA for all species except U. chlorophthalmus. The high values detected for fatty acid trophic markers (essential C 18 and C 20 PUFAs) and odd-numbered fatty acid suggest that Uca species occupy medium trophic level, primarily omnivores and scavengers/detritivores consuming algae common in the intertidal habitats. The fatty acid consumption pattern during embryonic development was essentially similar between species with some variation as expected, as FA content varies within species mainly due to female feeding ecology, nutritional and physiological conditions, differential demands on resource allocation and geographic and seasonal variations in embryonic development. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction The egg plays a central role in the life history of marine inver- tebrates, enclosing the energy source for the developing embryo and providing structural components during early ontogeny (e.g. Turner and Lawrence, 1979; Clarke, 1993). Clutch size varies greatly in decapods (Pandian, 1994) and egg size serves as an indicator of energy content (Jaeckle, 1995). Therefore, differences in egg dimension reflect real differences in maternal investment per embryo in caridean decapods (Clarke, 1993). Moreover, the biochemical changes that occur during ontogeny are essential for a complete understanding of crustacean reproduction, allowing the estimation of the nutritional requirements for embryos and exog- enous feeding larvae, which can be used in improving broodstock condition (Chen, 1998). The yolk molecules are mainly made up of proteins, free amino acids, lipids and carbohydrates (Pandian, 1970; Sasaki et al., 1986). Although protein is the main component of the eggs in marine invertebrates (Holland, 1978), lipids play a central role in the embryonic metabolism since they represent the most important energy source and form at least 60% of the total energy expenditure of the developing crustacean embryo (Herring, 1974; Holland, 1978; Amsler and George, 1984). Lipids are used by the developing embryo both as substrates for energy metabolism, explicitly acyl- glycerols but also polar lipids (Sargent, 1995), and as structural components in membrane biogenesis, namely phospholipids and cholesterol (Rosa et al., 2003, 2005). Crustaceans are well known for their environmental plasticity, with species adapted to a great variety of environmental condi- tions. The preferential utilization of neutral and/or polar lipids as energy source is species dependent and may reflect environmental adaptations (Narciso, 1999). Therefore, the eggs’ fatty acids (FA) content and dynamics provide information on life history traits, feeding ecology and habitats (Rosa et al., 2007). Thus, the quantity and quality of embryo FA reserves are important parameters that impact larval quality and survival, since the rate of FA utilization is a useful determinant of the nutritional requirements of crustacean larvae. The biochemical composition of crustacean eggs has been fairly well investigated (see Pandian, 1994 for a review) and several studies report on the constituents of decapod eggs during embryogenesis (e.g. Pandian, 1970; Herring, 1973; Amsler and * Corresponding author. E-mail address: biol.paulo@gmail.com (P. Torres). Contents lists available at ScienceDirect Estuarine, Coastal and Shelf Science journal homepage: www.elsevier.com/locate/ecss 0272-7714/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.ecss.2008.07.018 Estuarine, Coastal and Shelf Science 80 (2008) 307–313