Luís Narciso

MARINE ORNAMENTAL DECAPODS—Popular, Pricey, And Poorly Studied

Abstract The growing demand for highly priced marine ornamental species has contributed to the endangered status of coral reefs. A list of 128 of the most heavily traded marine ornamental decapod crustacean species is tabulated. The development of commercial culture techniques, the knowledge of the larval development, and the association with vertebrate and invertebrate organisms are presented for these species. Forty-nine of the species are caridean shrimp, with the Hippolytidae family alone accounting for 15. Anomuran and brachyuran crabs are the next most traded groups (32 and 27 species, respectively), with the pricey stenopodidean shrimp, Astacidea, and Palinura lobsters being represented by a considerably lower number of species (7, 7 and 6, respectively). The main bottlenecks impairing the commercial culture of ornamental shrimp and lobsters are their long larval development and poor survival rates. The main constraint for the development of culture techniques for hermit and brachyuran crabs is their low commercial value. The ecological impacts of harvesting ornamental species are still poorly studied. Nevertheless, the collection in considerable numbers of hermit and small majid crabs (e.g., Clibanarius and Mithraculus) from tidal areas, fish cleaning shrimp (e.g., Lysmata and Stenopus), and the crown-of-thorns sea star eaters Hymenocera, is likely to have serious impacts on the ecosystem. The cooperation between researchers working on larval biology, population dynamics, ecology, aquaculture, and fisheries is essential to properly manage the collection of marine ornamental decapods.

Influence of temperature in thermal and oxidative stress responses in estuarine fish

The influence of increasing temperatures in thermal and oxidative stress responses were studied in the muscle of several estuarine fish species (Diplodus vulgaris, Diplodus sargus, Dicentrarchus labrax, Gobius niger and Liza ramada). Selected fish were collected in July at the Tagus estuary (24±0.9°C; salinity of 30±4‰; pH=8). Fish were subjected to a temperature increase of 1°C.h(-1) until they reached their Critical Thermal Maximum (CTMax), starting at 24°C (control temperature). Muscle samples were collected during the trial and results showed that oxidative stress biomarkers are highly sensitive to temperature. Results from stress oxidative enzymes show alterations with increasing temperature in all tested species. Catalase (CAT; EC 1.11.1.6) activity significantly increased in L. ramada, D. labrax and decreased in D. vulgaris. Glutathione S-transferase (GST; EC 2.5.1.18) activity increased in L. ramada, D. sargus, D. vulgaris, and D. labrax. In G. niger it showed a cycle of increase-decrease. Lipid peroxidation (LPO) increased in L. ramada, D. sargus and D. labrax. With respect to correlation analysis (Pearson; Spearman r), the results showed that oxidation products and antioxidant defenses were correlated in L. ramada (LPO-CAT and LPO-GST, D. sargus (LPO-CAT), and D. labrax (LPO-CAT). Oxidative biomarkers were correlated with thermal stress biomarker (Hsp70) in L. ramada (CAT-Hsp70), D. vulgaris (LPO-Hsp70), D. labrax (GST-Hsp70) and G. niger (LPO-Hsp70). In conclusion, oxidative stress does occur with increasing temperatures and there seems to be a relation between thermal stress response and oxidative stress response. The results suggest that oxidative stress biomarkers should be applied with caution, particularly in field multi-species/multi-environment studies.

A rearing system for the culture of ornamental decapod crustacean larvae

Abstract The design and operation of a small research scale and a mass commercial scale rearing system for the culture of marine ornamental decapod crustacean larvae are described in the present paper. Preliminary data on the culture of the Mediterranean cleaner shrimp ( Lysmata seticaudata ), peppermint shrimp ( Lysmata wurdemanni ), blue-white partner shrimp ( Periclimenes sagittifer ), sponge crab ( Cryptodromiopsis antillensis ) and green emerald crab ( Mithraculus sculptus ) are also presented. The use of these “plantonkreisel” based systems allowed the complete larval development of the above-mentioned species, inducing minimal mechanical stress while keeping an excellent water quality. Higher survival rates (up to 70% and 60% for L. seticaudata and L. wurdemanni , respectively) to the post-larval stage and a shorter larval stage duration (27 and 22 days for L. seticaudata and L. wurdemanni , respectively) were achieved, in comparison to conventional rearing systems. This culture technology may play a key role in the realisation of a commercial culture of these highly priced crustacean species and therefore the reduction of wild specimen collection.

Lipid enrichment for Senegalese sole (Solea senegalensis) larvae: effect on larval growth, survival and fatty acid profile

Results from three larval Senegalese sole (Solea senegalensis) feeding trials using non-enriched Artemia and Artemia enriched with Super HUFA®, Arasco®, sunflower oil and microalgae are presented and the effects on larval survival, growth and fatty acid (FA) composition are reported. The FA profile of Senegalese sole eggs was analysed to gather information about the nutritional requirements of the early larval stages and a quite high DHA/EPA ratio (4.3) was found. However, there was no evidence of a high dietary demand for DHA or EPA, given that no relationship was found between dietary HUFA concentration and larval growth and survival. When larvae were fed non-enriched Artemia a significantly better growth and comparable survival were obtained than with Artemia enriched with Super HUFA® (containing the highest HUFA level and DHA/EPA ratio). The FA profiles of the larvae generally reflected those of their diets. DHA was an exception, as it was present in high proportions, even in larvae fed DHA-deficient prey. Total FAME concentration decreased during larval development, with SFA, MUFA and PUFA being equally consumed; HUFA appeared to be less used, with its relative concentration being either kept constant (particularly EPA and ARA) or increased (DHA). A specific requirement for ARA in the first larval stages could not be confirmed but it was always present in considerable amounts, even in larvae fed an ARA poor diet.

Gonad development and fatty acid composition of Patella depressa Pennant (Gastropoda : Prosobranchia) populations with different patterns of spatial distribution, in exposed and sheltered sites

The present study examines the effect of shore exposure on the feeding performance (assessed by fatty acid analyses of the whole body) and gonad condition (stage of development and gonad somatic index, GSI) of Patella depressa populations. Male and female limpets were collected at exposed and sheltered sites, during winter and summer. The population at the exposed site was at a more advanced stage of gonad development, with a higher dispersion of gonad stages, both in winter and summer. Additionally, limpets from the exposed site, particularly the males, presented a higher GSI than the corresponding stage in the sheltered site. The quantitatively most important fatty acids were the saturated fatty acids (SFA) 16:0, 14:0, and 18:0, the monounsaturated fatty acids (MUFA) 18:1(n-7), 18:1(n-9), 16:1(n-7) and 20:1(n-9) and the polyunsaturated fatty acids (PUFA) 20:5(n-3) and 20:4(n-6). Females had a significantly higher fatty acid methyl esters (FAME) content (in summer and winter) and higher amounts of SFA and MUFA (in summer), which points to a higher degree of storage of neutral lipids in this sex. Male and female limpets at the exposed site had a significantly higher FAME, SFA, MUFA, PUFA and highly unsaturated fatty acids (HUFA) content than the corresponding sex in the sheltered site in summer. In addition, an inversion in the eicosapentaenoic acid (EPA)/arachidonic acid (ARA) and (n-3)/(n-6) ratios was observed in the sheltered site, as a result of the significantly higher levels of ARA and (n-6) fatty acids and lower amounts of EPA and (n-3) fatty acids found in the sheltered limpets. A high variability among patches in the fatty acid composition in the exposed site was found in winter, possibly related to the aggregation of limpets at this time. The differences found between limpets from the exposed and sheltered sites suggest qualitative and quantitative differences in their diets. Additionally, the results show that the spatial aggregation strategy adopted by limpets in sites of great wave and wind exposure does not affect their feeding and reproductive success, at least in the site examined here. In fact, more developed gonads, a higher GSI and an elevated FAME content was found in the exposed population. Possible factors are suggested and discussed to explain these observations.

Biochemical changes during the embryonic development of Norway lobster, Nephrops norvegicus

The objectives of the present study were to investigate the total and free amino acid profiles and lipid dynamics (lipid classes and fatty acids) during embryogenesis of Nephrops norvegicus, in order to understand the early larval protein and lipid requirements. There was a significant increase in total essential (EAA) and nonessential amino acid (NEAA) contents during embryonic development (P<0.05). The major EAA were arginine, histidine and leucine, while the most important NEAA were glutamic acid, aspartic acid, glycine and proline. The higher percent increase occurred in respect to NEAA (19.9%), mainly due to the significant increase of glycine (51.8%) and alanine (35.1%). The free amino acid (FAA) content, especially the free nonessential amino acids (FNEAA), also increased significantly, being the quantitatively most important glycine, proline, taurine and glutamic acid. The free essential amino acids (FEAA) also revealed significant variations and the most important were arginine, lysine and leucine. A higher percent increase was attained with FNEAA (66.8%) in comparison to FEAA (49.6%), mainly due to the significant increase of homocystine (87.7%), valine (83.5%), glutamine (82.5%) and glutamic acid (76.1%). The absorption of dissolved organic compounds from seawater can explain the increase in free and total amino acid (FAA and TAA) contents, because a significant increase in the water content during development was observed (P<0.05). A substantial decrease in all neutral lipid classes (P<0.05) was observed during embryonic development, namely diacylglycerols (DAG) (97.9% of utilization), triacylglycerols (TAG) (93.2%), sterol esters (StE) (91.3%) and monoacylglycerols (MAG) (90.4%). The quantitatively most important fatty acids were the saturates (SFA) 14:0, 16:0 and 18:0, the monounsaturates (MUFA) 16:1n-7, 18:1n-9 and 18:1n-7, and the polyunsaturates (PUFA) 18:2n-6, 18:3n-3, 20:4n-6, 20:5n-3 and 22:6n-3. The unsaturated fatty acids (UFA) are used up at a higher rate (54.5% of utilization) than SFA (42.8%); within the UFA, MUFA are more consumed than PUFA (59.3% and 52.7%, respectively). In terms of the utilization of individual fatty acids, there was a preferential consumption of 20:4n-3, 22:6n-3, 18:1n-9, 22:5n-3 and 16:1n-7. It is evident that N. norvegicus depends primarily on lipid reserves of the egg during early ontogeny. On the contrary, this species tends to conserve EAA and increase NEAA and FNEAA contents during embryonic development.

Spatial and temporal variation of the fatty acid composition of Patella spp. (Gastropoda: Prosobranchia) soft bodies and gonads

This study evaluated the effects of season and spatial distribution on the fatty acid composition of Patella depressa gonads and Patella spp. soft body tissue. The results show that the quantitatively most important fatty acids were the saturated fatty acids (SFA) 16:0, 14:0 and 18:0; the monounsaturated fatty acids (MUFA) 18:1(n-7), 18:1(n-9), 16:1(n-7) and 20:1(n-9) and the polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA 20:5(n-3)), and arachidonic acid (ARA 20:4(n-6)). P. depressa and P. ulyssiponensis soft body fatty acid profiles revealed significant differences between sexes; males showed significantly higher percentages of PUFA, highly unsaturated fatty acids (HUFA), (n-3) fatty acids and ARA, while in females significantly higher proportions of MUFA were found. Analysis of variance on the fatty acid composition of P. depressa gonads revealed significant differences between sexes, which were more marked than when the whole body was analysed. Males showed a significantly higher percentage of PUFA, HUFA, fatty acids from the (n-3) and (n-6) series, ARA and EPA, while females were seen to have higher proportions of SFA, MUFA and total fatty acid methyl esters (FAME). Some variability was seen to occur due to shore location and seasons, but these effects were not so obvious.

FATTY ACID PROFILE OF PALAEMON SERRATUS (PALAEMONIDAE) EGGS AND LARVAE DURING EMBRYONIC AND LARVAL DEVELOPMENT USING DIFFERENT LIVE DIETS

Abstract Palaemon serratus (Pennant, 1777) is a shrimp with a high market value. It can be extensively produced in salt marshes with good survival rates, and it takes a reasonable period (8–10 months) to attain marketable size. For these reasons, it seems to have a good aquaculture potential. However, little is known about the nutritional requirements of this species, especially at the larval stages, and this may impose constraints to its successful rearing. This paper describes the changes occurring in the fatty acid profile of four developmental stages of Palaemon serratus eggs, newly hatched Zoea I larvae, and Zoea I starved for 24 and 48 hours, with the purpose of assessing larval fatty acid requirements. We also studied the effects of eight diets composed of microalgae (Chlorella sp. and Isochrysis galbana), rotifer (Brachionus plicatilis) and non-enriched or enriched brine shrimp (Artemia franciscana) nauplii on the fatty acid profiles of P. serratus postlarvae. Analysis of the P. serratus eggs reve...

Monitoring anthropogenic sewage pollution on mangrove creeks in southern Mozambique: A test of Palaemon concinnus Dana, 1852 (Palaemonidae) as a biological indicator

Tropical coastal ecosystems, such as mangroves, have a great ecological and socioeconomic importance for adjacent systems and local populations, but intensive environmental impact monitoring is still lacking, mainly in East Africa. This study evaluated the potential anthropogenic disturbance on Palaemon concinnus population structure and fitness. Palaemon concinnus populations from one peri-urban (domestic sewage impacted) and two pristine mangrove creeks were studied by sampling nearly 100 shrimps per location every 15 days for 12 months. The shrimps at the peri-urban location were larger, experienced longer reproductive periods, presented higher proportion of ovigerous females and better embryo quality when compared with shrimps inhabiting pristine locations. Physiological indices (RNA/DNA ratio) were similar between shrimps at pristine and peri-urban mangroves. However, a higher level of parasitation by a Bopyridae isopod, Pseudione elongata indicated some degree of stress on the host at the peri-urban mangrove, with potential effects on the host population dynamics.

Temporal fatty acid dynamics of the octocoral Veretillum cynomorium

The objectives of the present work were to investigate the temporal variation in the fatty acid (FA) composition of the octocoral Veretillum cynomorium, examine the effects of reproduction and environmental factors on FA variation, and establish a chemotaxonomic identification for this species. Mean oocyte size-frequency distributions showed that the majority of the oocytes had an intermediate size (Group II) before spawning (April and June). The late-vitellogenic oocytes (Group III) became absent in August and October and, during this post-spawning period, oocytes were primarily of small size (Group I). Most of the major FA, 16:0, 18:0, 20:4n-6, 20:5n-3, and the tetracosapolyenoic fatty acid (TPA), 24:6n-3, varied significantly throughout the year (p<0.01), with two peaks in August/October and February. The boost in early oogenesis, also associated with warmer temperatures, seemed to be responsible for the observed increase in FA content between June and August. The highest values of FA content were observed in February when intermediate oogenesis (Group II) was at its peak and there were considerable levels of available food in the environment. Also, the increase in food availability seemed to trigger the final stages of gametogenesis. The high quantity of 18:1n-7, odd-numbered and branched FAs, suggested the presence of a dynamic bacterial community in V. cynomorium, probably as an adaptive response to the lack of symbiotic microalgae. Although the presence of TPAs is the main feature distinguishing octocorals from other coral species, here we showed that there was no single FA clearly dominating the FA composition of V. cynomorium throughout the year. Instead, four main FAs share similar concentrations: 16:0, 20:4n-6, 20:5n-3 and 24:6n-3. The predominance of these four FAs combined with the higher amount of 24:6n-3 when compared to 24:5n-6 may serve as a chemotaxonomic feature to distinguish this octocoral species (or genus).