Effect of lipid emulsions on production and fatty acid composition of eggs of the scallop<Emphasis Type="Italic"> Argopecten purpuratus</Emphasis>

The impact of supplementing lipid emulsions rich in eicosapentaenoic acid (EmEPA), docosahexaenoic acid (EmDHA) or saturated fatty acids (EmCOCO) to a standard algal diet [3:1 mixture of Isochrysis galbana (T-iso) and Chaetoceros neogracile, St-diet] on Argopecten purpuratus broodstock was evaluated. Broodstock fecundity was compared as well as the egg quality in terms of lipid content, fatty acid composition and lipid class distribution. Fecundity was defined as the number of eggs released in the spawning process, since spawning was virtually complete. Results indicated that the total lipid content of the eggs of A. purpuratus was diet independent. A greater energy reserve was spent on a larger number of oocytes and not on bigger sized oocytes with a higher lipid content. The lipids supplied through the emulsions were at least partially allocated to the eggs, demonstrating that the fatty acid composition of the eggs could be manipulated, especially the neutral lipid fraction. Levels of EPA changed more rapidly than DHA levels, supporting the observation that they fulfilled an energetic and structural role, respectively. The St-diet supplemented with 50%EmCOCO resulted in a significantly higher fecundity compared to the algal diet supplemented with 25%EmEPA+25%EmDHA and the non-supplemented algal diet. It would seem that saturated fatty acids (SAFA) were more easily or preferentially incorporated in the female gonads of A. purpuratus. The relative content of SAFA and 18:2( n-6) in these eggs rose significantly. The relative content of the highly unsaturated fatty acids, EPA and DHA, on the other hand was substantially lower in the neutral lipid fraction, but hardly affected in the polar lipid fraction. It appeared that the maintenance of an adequate DHA/EPA ratio (approximately 1.2) was more important than the absolute levels of the two fatty acids, as long as a threshold value was reached.     

The ecological significance of lipid/fatty acid synthesis in developing eggs and newly hatched larvae of Pacific cod (Gadus macrocephalus)

The lipid/fatty acid composition of marine fish eggs and larvae is linked with buoyancy regulation, but our understanding of such processes is largely restricted to species with pelagic eggs. In this study, we examined developmental changes in the lipid/fatty acids of eggs and embryos of Pacific cod (Gadus macrocephalus), a species that spawns demersal eggs along coastal shelf edges, but as larvae must make a rapid transition to the upper reaches of the water column. Adult Pacific cod were collected in the Gulf of Alaska during the spawning season and eggs of two females were artificially fertilized with sperm from three males for each female. The eggs were subsequently reared in the laboratory to determine (1) how lipids/fatty acids were catabolized during egg and larval development, and (2) whether lipid/fatty acid catabolism had measurable effects on egg/embryo density. Eggs incubated at 4°C began hatching after 3-weeks and continued to hatch over a 10-day period, during which there was a distinct shift in lipid classes (phospholipids (PL), triacyglycerols (TAG), and sterols (ST)) and essential fatty acids (EFAs: 22:6n-3 (DHA), 20:5n-3 (EPA), and 20:4n-6 (AA)). In the egg stage, total lipid content steadily decreased during the first 60% of development, but just prior to hatch we observed an unexpected 2–3-fold lipid increase (~6–9 μg individual⁻¹) and a significant drop in egg density. The increase in lipids was largely driven by PL, with evidence of long-chained fatty acid synthesis. Late-hatching larvae had progressively decreasing lipid and fatty acid reserves, suggesting a shift from lipogenesis to lipid catabolism with continued larval development. Egg density measures suggest that lipid/fatty acid composition is linked to buoyancy regulation as larvae shift from a demersal to a pelagic existence following hatch. The biochemical pathway by which Pacific cod are apparently able to synthesize EFAs is unknown, therefore representing a remarkable finding meriting further investigation.     

Biochemical composition of cephalopods with different life strategies,with special reference to a giant squid,<Emphasis Type="Italic"> Architeuthis</Emphasis> sp.

The present study is a comprehensive comparison of the biochemical composition (protein, lipid, glycogen and cholesterol contents, and amino acid and fatty acid profiles) of 14 species of cephalopods with different life strategies (benthic, nektobenthic, benthopelagic and pelagic) in distinct habitats (neritic, demersal, oceanic and deep sea), with special emphasis placed on a male Architeuthis sp. The giant squid showed a significantly lower protein and total amino acid content in the gonad and digestive gland. The major essential amino acids were leucine, lysine and arginine. The major non-essential amino acids were glutamic acid, aspartic acid and proline. The benthopelagic cirrate octopus Opisthoteuthis sp. showed a lower content of these nitrogen compounds in the muscle. In respect to lipid and fatty acid contents, the giant squid showed the highest values in the gonad and digestive gland and the lowest in the muscle. Most of saturated fatty acid content was presented as 16:0; monounsaturated fatty acid content, as 18:1 and 20:1; and polyunsaturated fatty acid content, as 20:4n-6, 20:5n-3 and 22:6n-3. The highest cholesterol content in the gonad was detected in Opisthoteuthis sp. and Architeuthis sp.; in the digestive gland. in Todarodes sagittatus; and in the muscle, in Sepia elegans. The highest glycogen value in the gonad was detected in Octopus vulgaris; in the digestive gland and muscle, the highest values were attained in Opisthoteuthis sp. The relationships between life strategies and biochemical composition were investigated and principal component analysis (PCA) was performed. The different cephalopod life strategies could be well separated on the basis of the first two principal components. The nektobenthic and pelagic strategies were clearly separated from the benthic, suggesting that these groups of species are characterized by lower lipid content and higher protein content in the gonad. A rather similar life-strategy distinction was obtained for the digestive gland. The benthopelagic strategy was also well separated from benthic and pelagic strategies and from Architeuthis sp. In the muscle, the results indicated lower nitrogen and carbon compound contents in Architeuthis sp. and Opisthoteuthis sp. The environmental conditions that possibly explain the Architeuthis sp. stranding, the relationships between biochemical compositions and the life strategies of the different cephalopod species studied are discussed.Communicated by S.A. Poulet, Roscoff     

Comparative biochemical composition of ploidy groups of the lion-paw scallop (<Emphasis Type="Italic">Nodipecten subnodosus</Emphasis> Sowerby) supports the physiological hypothesis for the lack of advantage in triploid mollusc’s growth in food-rich environments

Induction of triploidy in aquatic organisms has increased worldwide in the last two decades, mostly because triploids have better growth than diploids. According to a physiological hypothesis, partial or total sterility of triploids allows the accumulation of reserves in muscle and other tissues instead of being transferred to the gonad. The present study analyzes lipid, protein, carbohydrate, and fatty acid levels in muscle and gonads of Nodipecten subnodosus triploids and diploids over 18 months from June 2001 to December 2002. An important increase in gonadosomatic index of diploids scallops was observed from May to June 2002 reaching the highest values in August. Such increase was not observed in triploid scallops. Changes in biochemical composition in female gonad were in general related to the accumulation of reserves during gonad development of diploid scallops. This accumulation was lower for triploid scallops, in accordance to their sterility, especially for carbohydrates and acylglycerides. Adductor muscle index as well as protein and carbohydrate levels in muscle increased in both ploidy groups during the reproductive period indicating no mobilization of reserves to sustain gonad development in both ploidy groups. These results partially support the physiological hypothesis on the advantage of triploids: in a rich food locality no mobilization of reserves is needed to sustain gametogenesis. This, together with a possible lower efficiency of energy assimilation at high food concentration for triploids, may be the reason for an apparent lack of superiority of N. subnodosus triploids in terms of adductor muscle growth. Only the levels of particular highly unsaturated fatty acids levels (namely 20:4n-6 and 20:5n-3) in muscle of diploid and triploid decreased during the reproductive period, indicating a possible transfer of selected fatty acids to gonads, even in triploids. The muscle of triploids has a slightly but significantly higher proportion of 22:6n-3 compared to diploids, which can have implications for the nutritional and commercial value of triploid adductor muscle.     

Fatty-acid composition of ovulated eggs from wild and cultured turbot (Scophthalmus maximus) in relation to yolk and oil globule lipids

The fatty-acid composition of lipids from ovulated eggs of wild and cultured turbot was investigated in order to estimate the nutritional requirements during embryonic and early larval development. Lipid comprised 13.8±0.5% (n=5) and 13.2±0.7% (n=7) of the egg dry weight in wild and cultured turbot, respectively. Polyunsaturated fatty acids (PUFA) of the (n-3) series accounted for 39% of total fatty acids in total lipid of both wild and cultured fish. The predominant (n-3) FUFA was docosahexaenoic acid (22:6 n-3), which also was the most abundant fatty acid in turbot eggs and comprised 24 and 23% of the total egg fatty acids in wild and cultured fish, respectively. Phospholipids, triacylglycerols and cholesterol-wax esters of turbot eggs all exhibited a specific fatty-acid profile distinctly different from that of total lipid. The general pattern of the fatty-acid distribution in lipids of eggs from wild and cultured turbot was similar, but the relative amount of 18:2(n-6) was considerably higher and 20:1(n-9) slightly higher in cultured fish. These differences were extended to all lipid classes and probably reflect the dietary intake of certain vegetable and marine fish oils. Calculations based on light microscopical studies showed that 55 to 60% of the total lipids in cultured turbot eggs are confined to the oil globule. The size of the oil globule remained constant during embryogenesis, and a reduction in size occurred first after hatching and mainly after yolk depletion. This implies that the total amount of lipids utilised during the embryonic development is considerably less than the total lipids present in ovulated turbot eggs. Comparison of the fatty-acid composition of total lipids from eggs and vitellogenin of wild turbot reveals that egg lipids contained a lower level of saturated and a higher level of monounsaturated fatty acids. Eggs also contained wax esters, which were not detected in vitellogenin, suggesting that vitellogenin is not the only source of lipids for turbot eggs.     

Lipids and fatty acids as indicators of egg condition,larval feeding and maternal effects in Cape hakes (<Emphasis Type="Italic">Merluccius paradoxus</Emphasis> and <Emphasis Type="Italic">M. capensis</Emphasis>)

Cape hakes, Merluccius paradoxus and M. capensis, are important gadoid fish that are commercially harvested in the Benguela Current system off Namibia and South Africa. The aim of this study was to elucidate the nutritional condition and feeding preferences of their larvae. Hake eggs and larvae were sampled in austral spring of two consecutive years, 2007 and 2008, off the west coast of South Africa. They were identified to species using genetics, and total lipid content and fatty acid (FA) composition were analysed for each individual egg and larva to compare the condition of different early life stages of both hake species. Higher abundances of M. paradoxus eggs and larvae were consistently found compared to M. capensis. In both species, eggs contained wax esters (WE) and had significantly higher lipid content per dry mass than larvae. Lipid content as well as FA composition changed with the developmental stage of larvae. Quantities of essential fatty acid (EFA) increased with feeding of larvae due to dietary lipid incorporation. In 2007, yolk-sac larvae contained significantly lower total lipids than in 2008. It is argued that this was due to reduced lipid transfer by the spawning females to the eggs. These findings indicate that maternal effects are important in determining condition of hake larvae and that this may have an effect on their survival and subsequent recruitment.     

Changes in morphology and physiology of an East Mediterranean sponge in different habitats

The sponge Tetilla sp. (Tetractinomorpha: Tetillidae) is a common species in the eastern Mediterranean. This sponge inhabits four different habitat types differing in wave impact and irradiance levels. Two of these habitats (a shallow cave and deep water) are characterized by relatively calm water, whereas the other two (shallow exposed site and tide pools) are in turbulent water with high energy flow. The present study examined the influence of physical (depth, illumination and water motion) and biotic factors on morphology, skeletal plasticity and reproductive traits among the four spatially separated populations. Sponges from tidal pools had significantly larger body volume than sponges from deep water and from shallow caves (ANOVA: tidal-deep P<0.0001; tidal-shallow caves P<0.05). Sponges from exposed habitats were significantly larger than deep-water sponges (ANOVA: P=0.01). In addition, individuals from tide pools and from the exposed habitat had a significantly higher proportion of structural silica than sponges from the calmer deep water and from the cave sites. Oxea spicules in sponges from the calm habitats were significantly shorter than in those from the tidal pools and the exposed habitats. The percentage of spicules out of a sponges dry weight in individuals transplanted from deep (calm) to shallow (turbulent) water significantly increased by 21.9±12.9%. The new spicule percentage did not differ significantly from that of sponges originally from shallow water. Oocyte diameter differed significantly between habitats. The maximal size of mature eggs was found in deep-water sponges in June (97±5 m). In the shallow habitats, a smaller maximal oocyte diameter was found in the cave, in May (56.5±3 m). Furthermore, oocyte density in shallow-water sponges was highest in May and decreased in June (with 88.2±9 and 19.3±9 oocytes mm^–2, respectively). At the same time (June), oocyte density of deep-water sponges had just reached its maximum (155±33.7 oocytes mm^–2). The difference in oocyte size and density between deep- and shallow-water individuals indicates an earlier gamete release in the shallow sponge population. The results suggest that plasticity in skeletal design of this sponge indicates a trade off between spicule production and investment in reproduction.Communicated by O. Kinne, Oldendorf/Luhe     

Lipid composition and partitioning of deepwater chondrichthyans: inferences of feeding ecology and distribution

The composition of lipids and fatty acids was determined for the livers, muscle, pancreas, kidney and stomach fluids of deepwater chondrichthyan species (including 11 squaliformes, 3 chimaeriformes, 1 hexanchiforme and 3 carcharhiniformes) caught as bycatch from continental waters off south-eastern Australia. The lipid class, fatty acid and fatty alcohol composition differed markedly in each tissue and in each species. The lipid and fatty acid composition of large, lipid-rich (38–70% wet weight, ww) livers demonstrated the multifunctional role of this organ in: lipid distribution, storage and biosynthesis, and buoyancy regulation. In the liver, the importance of certain lipids (including squalene, diacylglyceryl ethers, triacylglycerols and to a lesser extent wax esters) as mediators of buoyancy varied according to lifestyle and habitat. Less variability was observed in the muscle profiles, characterized by low lipid content (<1.0% ww) and high relative levels of polar lipids (>70%). The lipid and fatty acid profiles of the kidney and pancreas showed the highest intraspecific variability, suggesting these organs also have complex roles in lipid storage and metabolism. Overall intra- and interspecific differences in the tissue fatty acid profiles could be related to differences in a number of factors including phylogeny, habitat (depth), buoyancy regulation and diet and presumably also reflect different ecological roles. The lipid and fatty acid profiles are the first published for Rhinochimaera pacifica, Chimaera lignaria and Figaro boardmani and the first to demonstrate interspecific variation in lipid profiles of various tissues of deepwater chondrichthyans. The application of multivariate analysis to lipid class and fatty acid tissue profiles in chondrichthyans inferred dietary differences and metabolic preferences between species and habitats. These results have important implications for the future use of fatty acids as dietary tracers in chondrichthyan research.     

Lipid composition of<Emphasis Type="Italic"> Symphodus ocellatus</Emphasis> (Perciforme: Labridae) in the north-western Mediterranean: influence of two different biotopes

The lipid content and fatty acid composition of the small common wrasse Symphodus ocellatus was analysed within two populations located in very different biotopes on the French shore: a Caulerpa taxifolia meadow located in Cap Martin and a Posidonia oceanica bed located in Villefranche. Polar lipids represented 82–90% of the total lipid in adult female livers, gonads and in eggs. Cholesterol in gonads and eggs and triacylglycerols in livers were the dominant neutral lipids. Differences in lipid classes were found in livers between the two populations, but not in their gonads and eggs. Moreover, a quantitative difference in total lipid content was evident. Young fish living on the C. taxifolia meadow in winter had 21% less lipid than those living on the P. oceanica bed. The populations of S. ocellatus showed differences between triacylglycerol versus phospholipid fatty acid compositions and between gonad versus liver fatty acid compositions. Moreover, a significant difference was found between both populations in their liver triacylglycerol fatty acid compositions, suggesting a difference in diet. Gut content analysis supported this hypothesis as it showed important differences in the ingested preys between the two populations in January (planktonic vs. benthic, frequency of isopods) and in June (frequency of gastropods). Thus, we found that the fish populations from Villefranche and Cap Martin showed significant differences in body lipids due to different nutritional habits.Communicated by S.A. Poulet, Roscoff     

Spatial variability in lipid composition of calanoid copepods from Fram Strait,the Arctic

The calanoid copepods Calanus hyperboreus and C. finmarchicus were investigated in view of their lipid and wax ester content and their fatty acid and alcohol composition. Analyses were performed in females and copepodid stages V and IV from the Fram Strait region between Greenland and Spitsbergen in 1984. This region offers different food conditions like diatom blooms in the North East Water Polynya, food shortage in areas with very close ice cover, high phytoplankton biomass in the marginal ice zone and lower biomass in the open Atlantic water. Lipids contained generally more than 70% wax esters. Highest levels were found in C. hyperboreus with more than 90%. This percentage was not very variable, in spite of large differences in dry weight and lipid content. Copepods with particularly high weight and lipid content were found in the North East Water Polynya. The lightest individuals were found under the pack ice. Lipid proportions per unit dry weight were higher in C. hyperboreus than in C. finmarchicus, whose lowest values were found in the open Atlantic water. Spatial variability in fatty acid composition was much higher than in alcohol composition. The principle alcohols, 20:1 and 22:1, generally accounting for more than 80% of total alcohols. In the North East Water Polynya, the predominant monounsaturated fatty acid was 16:1, while under the ice 20:1 and 22:1 dominated. In the marginal ice zone and in the open water, the 18:4 acid reached percentages up to 30% of total fatty acids. These changes were related to the different food conditions. C. hyperboreus appears to be best adapted to the cold water and unfavourable conditions of polar regions because of its high lipid and wax ester store with long-chain wax esters of high calorific value.     

Changes in biochemical and fatty acid composition of the razor clam <Emphasis Type="Italic">Solen marginatus</Emphasis> (Solenidae: Bivalvia) during larval development

Aquaculture studies have revealed that polyunsaturated fatty acids are critical for maintaining substantial growth, survival and reproductive rates, and high food conversion efficiencies for a wide variety of marine and freshwater organisms. The aim of this study was to investigate the gross biochemical and fatty acid composition of both neutral and polar lipid compartments of the razor clam Solen marginatus throughout embryonic and larval development. High levels of stored reserves in S. marginatus eggs allow a short larval development, lasting only 8 days. The energy required for embryogenesis was obtained from stored proteins. During larval development from D-shaped veliger until settlement, protein, lipid, and carbohydrate reserves were indistinctly stored for metamorphosis. Although total lipids increased, fatty acids in both neutral and polar lipids decreased during embryonic development. The depots allow a short larval development in which settlement is reached with lower amounts of stored neutral and polar lipids than the contents found in the oocytes. Non-methylene-interrupted dienoic fatty acid levels were similar to those of some polyunsaturated fatty acids, with increasing percentages at the onset of metamorphosis. This study indicates that S. marginatus exhibits a different pattern in the use of gross biochemical and fatty acid reserves during larval development compared to other razor clam and bivalve species, mainly due to the large size of its eggs and the short larval development stage reported in this species.     

Changes in lipid content,lipid class composition and fatty acid composition of developing eggs and unfed larvae of cod (Gadus morhua)

Changes in the lipid class and fatty acid composition of developing eggs and unfed larvae of cod (Gadus morhua L.) were studied with the objective of determining probable requirements of cod larvae for dietary lipid. The eggs were collected on 24 March 1985 from holding tanks containing cod which had been caught off the northwest coast of Scotland. Phosphatidylcholine (PC) was the only lipid class to decline in absolute terms during embryogenesis. Catabolism of neutral lipid was initiated during the first week after hatching, and the rate of neutral lipid utilisation increased after the larvae had completely absorbed their yolk sacs. The quantity of triacylglycerol (TAG) remained constant during embryogenesis, but the percentage of 22:6(n-3) int TAG increased substantially during this period. It was calculated that ca. 33% of the 22:6(m-3) released during the process of PC catabolism was incorporated into TAG and sterol ester. The results suggest that PC, replete in appropriate essential fatty acids, should represent a major proportion of the lipid in artificial diets for fish and crustacean larvae.     

Influence of UV radiation on the survival of larvae from broadcast-spawning reef corals

Effects of ambient ultraviolet light on the survivorship of eggs and planulae larvae was investigated for three species of broadcast-spawning reef corals, Acropora palmata, Montastraea annularis, and M. franksi. Eggs and larvae from these corals contain high concentrations of lipids (60–70% by weight) and float in surface waters for 3–4 days following spawning. Larvae originating from colonies living at deeper sites on the reef exhibited significantly lower survivorship than conspecifics originating from parents in shallow water when experimentally exposed for up to 4 days to ambient surface levels of ultraviolet radiation (UVR). Concentrations of the UVR-protective compounds correlated positively with survival and matched concentrations found in parent colonies, implying that higher concentrations of ultraviolet B protective compounds are responsible for greater survival of eggs and larvae from shallow compared to deeper-dwelling parents. Ultraviolet B appears to be responsible for most of the observed differences in larval survivorship with ultraviolet A playing a minor or insignificant role. Data presented here indicate that coral recruits on Caribbean reefs and elsewhere may originate primarily from adult colonies dwelling in shallow water.Communicated by P.W. Sammarco, Chauvin     

Diets of fan shells (Pinna nobilis) of different sizes: fatty acid profiling of digestive gland and adductor muscle

Pinna nobilis is a large bivalve, endemic to the Mediterranean Sea that was shown in a previous study to ingest significantly different proportions of different food items according to its shell height. Fatty acid profiling of total lipids was used to examine these differences in diet in relation to shell size. Small (shell height 23.0 ± 3.3 cm), medium (SH 41.5 ± 5.5 cm) and large (SH 62.7 ± 4.8 cm) P. nobilis were collected from Mali Ston Bay, Adriatic Sea, in March 2010, and fatty acid analysis was performed on digestive gland and adductor muscle tissues. Based on the analysis of the digestive gland, small P. nobilis were associated with a detrital food chain, characterized by saturated and branched-chain fatty acids, while the diets of medium and large individuals had a greater proportion of polyunsaturated fatty acids. This likely reflects the fact that smaller individuals feed within the benthic boundary layer where the detritus concentrations are high. Fatty acid incorporation into the adductor muscle, likely representative of food taken up over a longer time period, was reversed, that is, larger individuals had lower levels of polyunsaturated fatty acids. This most probably reflects energy expenditure, which typically increases with increasing organism size.     

Biochemical composition and trophic strategies of the amphipod Eurythenes gryllus at hadal depths (Atacama Trench,South Pacific)

Amphipods Eurythenes gryllus were collected at 7800?m depth in the Atacama Trench (South Pacific) for studying their biochemical composition (in terms of proteins, lipids and carbohydrates and fatty acid content) and to gather information on bioenergetic strategies and trophic habits of organisms living in this extreme environment. The effect of long-term formalin storage on the biochemical determinations was also determined. Proteins were the dominant biochemical class of organic compounds (39–53%D.W.), whereas carbohydrates accounted for a very small fraction (1–2%D.W.). Lipid concentrations of E. gryllus accounted for 7–18%D.W. and were much lower than those reported for other deep-sea amphipods. These differences are likely to be more dependent upon food availability in the Atacama Trench rather than upon temperature. Lipid composition of E. gryllus revealed the dominance of monounsaturated fatty acids with polyunsaturated fatty acids accounting for a very small fraction, suggesting that hadal amphipods are higher dependent upon lipid reserves than amphipods inhabiting at shallow depths. The ratio of C18:1Δ⁹ to C18:1Δ¹¹ was >11 confirming the necrophagous trophic habits of this hadal amphipod.     

Lipids in atlantic halibut (Hippoglossus hippoglossus) eggs from planktonic samples in Northern Norway

Fertilized Atlantic halibut (Hippoglossus hippoglossus L.) eggs in different developmental stages (Days 0 to 18) were sampled from plankton in North Norway in February 1986 and analysed for lipid classes and fatty acid content. In unfertilized ovulated eggs taken from ripe fish caught in 1983/1984, polar and neutral lipids comprised ca. 71 and 30% of the total lipids, respectively, decreasing and increasing to 67 and 33%, respectively, in Stage III (11 to 18 d old) fertilized eggs. Of the polar lipids, phosphatidylcholine decreased markedly from 62% in unfertilized ovulated eggs to ca. 40% in Stage I (0 to 3 d old) fertilized eggs, while phosphatidylethanolamine increased from ca. 7 to 33%. Triacylglycerols, the major neutral lipids, increased from ca. 13% in unfertilized ovulated eggs to 16% in Stage III fertilized eggs. The total lipid in Stage I fertilized eggs had relatively low levels of polyunsaturated fatty acids (PUFA), with (n-3) PUFA accounting for only ca. 25% of the total fatty acids. The (n-3) PUFA increased to ca. 40% of the total fatty acids in Stage III, while the (n-3): (n-6) ratio increased from 4.1 to 7.0.     

Size and spatial structure in deep versus shallow populations of the Mediterranean gorgonian <Emphasis Type="Italic">Eunicella singularis</Emphasis> (Cap de Creus,northwestern Mediterranean Sea)

In the Western Mediterranean Sea, the gorgonian Eunicella singularis (Esper, 1794) is found at high densities on sublittoral bottoms at depths from 10 to 70 m. Shallow colonies have symbiotic zooxanthellae that deeper colonies lack. While knowledge of the ecology of the shallow populations has increased during the last decades, there is almost no information on the ecology of the deep sublittoral populations. In October and November 2004 at Cap de Creus (42°19′12″ N; 03°19′34″ E), an analysis of video transects made by a remotely operated vehicle showed that shallow populations (10–25 m depth) were dominated by small, non-reproductive colonies, while deep sublittoral populations (50–67 m depth) were dominated by medium-sized colonies. Average and maximum colony heights were greater in the deeper populations, with these deeper populations also forming larger patch sizes and more extensive regions of continuous substrate coverage. These results suggest that shallow habitats are suitable for E. singularis, as shown by the high recruitment rate, but perturbations may limit or delay the development of these populations into a mature stage. This contrasts with the deep sublittoral habitats where higher environmental stability may allow the development of mature populations dominated by larger, sexually mature colonies.     

Lipids of some Caribbean and Red Sea corals: total lipid,wax esters,triglycerides and fatty acids

The Caribbean reef-building corals Porites porites (Pallas) and Montastrea annularis (Ellis and Solander) and the Red Sea corals Pocillopora verrucosa (Ellis and Solander), Stylophora pistillata (Esper) and Goniastrea retiformis (Lamark) were analysed for total lipid, wax ester and triglyceride content, and fatty acid composition. M. annularis contained about 32% of dry weight as total lipid, whereas much lower values of between 11 and 17% were recorded for the other four species. It is concluded that there is greater variation in coral total lipid than hitherto thought. The total lipid contained a substantial proportion of wax ester (22 to 49%) and triglyceride (18 to 37%). The storage lipids (wax esters and triglycerides) accounted for between 6 and 20% of the dry weight and between 46 and 73% of the total lipid. Variation in lipid content between species could not be attributed to geographical location, but the low values for total lipid in Red Sea corals may in part be due to environmental factors as these samples were collected in winter. All corals analysed contained high levels of saturated fatty acids, the most abundant fatty acids being 16:0, 18:0 and 18:1n-9. Marked differences were observed in polyunsaturated fatty acid (PUFA) content between species, with comparatively low levels of 10 and 11% of fatty acids being recorded in M. annularis and G. retiformis, respectively. The values for the other species ranged between 21 and 37%. Fatty acid composition may vary according to the proportions of fatty acids obtained from diet, algal photosynthesis and synthesis by the animal tissues.     

Offshore marine cheilostome Bryozoa from Fort Lauderdale,Florida

Cheilostome Bryozoa were collected upon marine fouling test panels exposed offshore from Fort Lauderdale, Florida, USA between 1961 and 1967. Panels were exposed at certain depths, ranging from the surface to the bottom, in several arrays extending to a distance of 4 miles offshore. Twenty-three species were identified from the 114 panels recovered and examined. Most species were found on panels in shallow water, or on panels near the bottom in deeper, offshore water. A notable exception was a large, arborescent colony of Biflustra savartii which engulfed a panel 50 feet (15 m) deep, 4 miles from shore, in the Florida current. The lack of cheilostome Bryozoa on shallow and mid-water panels at the offshore, deepwater stations was apparently due to the low number of larvae reaching them from the distant inshore colonies.     

Neutral lipid compositions of antarctic fish tissues may reflect use of fatty acyl substrates by catabolic systems

Antarctic fishes contain large quantities of lipid in adipose tissue, blood and oxidative muscle. In this study, the fatty acyl compositions of free fatty acids (FFA) and triacylglycerol (TAG) in serum, adipose tissue and oxidative muscle were determined in two species of Antarctic fishes, Trematomus newnesi Boulenger, 1902, and Notothenia gibberifrons Lönnberg, 1905, collected off the Antarctic Peninsula in February and March 1987. Total lipid contents of serum and oxidative muscle in each species also were measured. T. newnesi, a mesopelagic species, has significantly more lipid in the serum than N. gibberifrons, a demersal species (17.6±2.4 and 10.4±1.0 mg lipid g^-1 serum, respectively). The oxidative muscle of T. newnesi also contains more lipid than does that of N. gibberifrons (12.5 and 9.3% by dry weight, respectively). Fatty acids comprising greater than 5% of one or more of the lipid pools assayed in both species include 14:0, 16:0, 16:1, 16:2, 18:0, 18:1, 20:5 and 22:6. The percentages of 16:1 were lower (p<0.05) in oxidative muscle FFA than in all other assayed lipid pools in both species, suggesting a catabolic preference for some monoenes in oxidative muscle of these fishes. The percentage of 14:0 was two-to three-fold higher in adipose tissue TAG than in all other lipid pools in both species. Differences in fatty acid compositions between lipid pools indicate than proteins involved in the mobilization, transport or catabolism of fatty acids exhibit differential recognition of fatty acids in T. newnesi and N. gibberifrons.