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- The impact of dietary supplementation with astaxanthin on egg quality and growth of long snout seahorse (Hippocampus guttulatus) juvenilesPublication . Palma, Jorge; Andrade, José Pedro; Bureau, D. P.This study investigated the effect of dietary astaxanthin supplementation on egg quality and juvenile growth of long snout seahorse (Hippocampus guttulatus). Captive breed seahorse broodstock were fed four diets composed of frozen shrimp [Atlantic ditch shrimp, Palaemonetes varians) used as a vector to deliver artificial diets with increasing levels of astaxanthin (0, 75, 100 and 125 mg kg(-1) dry weight)]. The results indicated that the astaxanthin uptake into eggs from the enriched shrimp diets was highly efficient. Females fed unsupplemented astaxanthin diet produced similar-sized eggs with lower concentration of astaxanthin than females fed diets with astaxanthin. The lower concentration of astaxanthin in the eggs was correlated with the production of smaller juveniles in comparison with the juveniles hatched from parents fed supplemented astaxanthin diets. Juvenile growth and survival was limited by their size on release from the male's pouch as at the end of 28-day postparturition juveniles produced with the diet with no astaxanthin were still significantly smaller (P < 0.05) than those produced from parents fed astaxanthin-supplemented diets. These results demonstrate a significant benefit of dietary astaxanthin supplementation in long snout seahorse diets in terms of improved egg quality and juvenile growth and survival.
- Optimization of live prey enrichment media for rearing juvenile short-snouted seahorse, hippocampus hippocampusPublication . Palma, Jorge; Lima, Ricardo; Andrade, Jose; Lança, Maria JoãoThis study aimed to determine a nutritionally adequate feeding protocol for Hippocampus hippocampus juveniles. In the experimental trial, seahorses were fed copepods from 0–7 days postparturition (DPP) and, from 8–28 DPP, four different dietary treatments: (copepods (control diet) (Cop); microalgae-enriched Artemia with a docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) ratio of 2:1 (ArtDHA/EPA); microalgae-enriched Artemia with a DHA/EPA ratio of 2:1 along with 5% copepods (ArtDHA/EPA5%); and with 10% copepods (ArtDHA/EPA10%)). At the end of the trial, juvenile seahorses fed Cop grew significantly more (p < 0.05) (5.1 mg d−1 ) than those on fish-fed diets ArtDHA/EPA5% or ArtDHA/EPA10% (3.09 and 3.07 mg d−1 , respectively), or those on the fish-fed ArtDHA/EPA (1.83 mg d−1 ) diet, all of which performed poorly. Data suggest that feeding copepods during the first 7 DPP promotes maturation of the digestive tract of juvenile seahorses, and the addition of a limited amount of copepods to the diet improves H. hippocampus juvenile growth performance when compared with the use of Artemia as a single diet due to the improvement of the essential fatty acid profile in the diets
- The effect of dietary sericite on growth performance, digestive enzymes activity, gut microbiota and haematological parameters of Nile tilapia, Oreochromis niloticus (L.) fingerlingsPublication . Hassaan, Mohamed S.; Mohammady, Eman Y.; Soaudy, Mohamed R.; Palma, Jorge; Shawer, Ehab E.; El-Haroun, EhabA feeding trial was conducted to assess the effect of dietary supplementation of sericite (silicate clay) on growth performance, digestive enzymes activity, immune parameters and gut microbiota, of Nile tilapia, Oreochromis niloticus (L.) fingerlings. Five isonitrogenous diets were formulated each diet supplemented with different levels of sericite 0 (control), 2.5, 5, 7.5 and 10 g/kg diet. After 70 days of feeding trial, supplemental sericite were quadratically improved the final body weight (FBW) (P = 0.023), weight gain (WG) (P = 0.012), specific growth rate (SGR) (P = 0.023) and feed conversion ratio (FCR) P = 0.023) and protein efficiency ratio (PER) (quadratic, P = 0.045). However, the relationship between FCR and sericite levels was expressed by a broken-line model with an identified optimal breakpoint of 6.3 g/kg of sericite inclusion in the diets. Additionally, significant quadratic increase in alkaline phosphatase (ALP), amylase, trypsin, chymotrypsin and lipase enzymes were detected (P = 0.026; P = 0.023; P = 0.013; P = 0.045; P = 0.023) as the level of sericite increased in the diet. Furthermore, dietary sericite levels exhibited linear decreased in the total count bacteria, E. coli and Enterobacteriaceae of stomach and gut of experimental fish (linear, P = 0.032; P = 0.024; P = 0.035; P = 0.023; P = 0.012; P = 0.039, respectively). There was no effect of dietary sericite levels on hemoglobin (Hb), hematocrit (Htc) and red blood cells (RBCs), but a quadratic trend was observed in white blood cells (WBCs), monocytes and lymphocytes of fish (quadratic, P = 0.036; P = 0.013; P = 0.034), respectively. Increasing dietary sericite levels did not affect alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin and globulin but quadratically increased total protein (quadratic, P = 0.012) and IgM exhibited linear trend (linear, P = 0.045). Results in this study indicate that the addition of sericite as feed additive enhanced the growth, feed utilization, digestive enzyme activities, blood profile and gut biota of Nile tilapia.
- A crown for each monarch: a distinguishable pattern using photo-identificationPublication . Correia, Miguel; Antunes, Daniela; Andrade, José Pedro; Palma, JorgePhoto-identification has been proven to be a successful individual recognition tool in seahorse species (e.g., long-snout seahorse Hippocampus reidi (Ginsburg, 1933) and long-snouted seahorse Hippocampus guttulatus (Cuvier, 1829)). Its use was deemed valuable for the assessment of wild populations and to understand variations in abundance over time when capture-recapture methods are needed. In this study, a computer software with a pattern recognition algorithm (I3S® Contour 3.0) was used for individual identification of short-snouted seahorses Hippocampus hippocampus (Linnaeus 1758) in the laboratory. Using this methodology, differences in the shape of each individual’s coronet were tested as a unique and distinguishable characteristic. Two different contours were used as reference and tested to assess the effectiveness of this method in individual identification. A total of 94 captive-bred H. hippocampus, 45 adults (> 1 year old) and 49 young adults (4 months old), were tested. Positive matches were obtained in 55.1 % of the young adults and 84.4 % of the adults using contour 1; and in 77.6 % and 97.8 % for young adults and adults, respectively, using contour 2. All un-matched photos were later successfully matched by visual comparison, using additional traits (e.g., spot patterns) and gender. This methodology yielded very promising results and could be further used in wild individuals to allow population size estimates.
- Gastric evacuation and feeding in the gilthead sea bream reared under semi-intensive conditionsPublication . Andrade, José Pedro; Erzini, Karim; Palma, JorgeGastric evacuation rates of the gilthead sea bream, Sparus aurata, fed with commercial pelleted food and polychaetes (Nereis diversicolor) were determined under experimental conditions. The estimated gastric evacuation rate for pelleted food was 7.97% h(-1), with a total time of digestion of approximately 9 h. The respective values for the natural food were 6.24% h(-1), with a total digestion time of approximately 12 h. The daily consumption of fish reared in earth ponds in a semi-intensive aquaculture facility was estimated through 24h cycles performed between April and August. The daily consumption varied from 18.58 to 31.98 mg g(-1). There was a constant increase in the average daily consumption per individual of 1.8-4.6 g (dry weight). During these cycles, samples of stomachs were taken and the contents preserved for further observation. The feeding behaviour of the reared fish was compared with a fish sample caught in the Ria Formosa lagoon. No common species were found between samples. A total of 38 prey were identified, which suggests that the gilthead sea bream is a non-specific predator. Despite the high abundance of natural prey in the ponds, the dependence of sea bream on pelleted food was high.
- Different behavioral strategies of two sympatric seahorses: habitat availability and increased density of Hippocampus guttulatus alter the behavior of Hippocampus hippocampusPublication . Spatafora, Davide; Gristina, Michele; Quattrocchi, Federico; Pierri, Cataldo; Lazic, Tamara; Palma, JorgeIn the light of future ocean warming scenarios and habitat fragmentation, coastal fishes must adjust their physiological and behavioral traits to face the combined effect of global warming and ecological interactions. Seahorses (Hippocampus spp.) are charismatic fishes with peculiar life cycle traits, which make them vulnerable to several anthropic pressures and natural disturbances. In this study, we investigated the behavior of two sympatric seahorse species, the long-snouted Hippocampus guttulatus (Cuvier, 1829) and the short-snouted Hippocampus hippocampus (Linnaeus, 1758). Specifically, we carried out two manipulative experiments to assess (i) the effect of temperature and habitat availability on both H. hippocampus and H. guttulatus behavior and (ii) the effect of temperature and an increased density of H. guttulatus (by 3x) on the activity level of congeneric species H. hippocampus. Our results showed that +3 & DEG;C warming did not affect seahorse behavior in both experiments, suggesting greater behavioral tolerance to thermal variation. However, a significant reduction of the active behavior of H. hippocampus was observed when the artificial habitat was introduced in the tank, while H. guttulatus maintained its activity. Furthermore, a significant decrease of the H. hippocampus activity was observed with an increased relative dominance of H. guttulatus. Our results suggest that both increased density of H. guttulatus and habitat availability, but not ocean warming, will affect the behavior of H. hippocampus. Therefore, different interspecific behavioral strategies may occur, thus affecting the distribution of the two species among shallow habitats when they occur in sympatry.
- Impacts of pineapple peel powder on growth performance, innate immunity, disease resistance, and relative immune gene expression of Nile tilapia, Oreochromis niloticusPublication . Palma, JorgeAn 8-week growth trial was conducted to examine the efficacy of pineapple peel powder (PAPP) on growth rate and immunity of Nile tilapia, O. niloticus. Three hundred Nile tilapia (20.91 ± 0.11 g) were fed five diets containing different levels of PAPP at 0, 10, 20, 30 and 40 g kg− 1 PAPP, respectively. After four and eight weeks of the feeding trial, growth rates, and immune responses were tested. A challenge test using Streptococcus agalactiae and relative immune gene expression were performed after eight weeks of PAPP feeding. It was found that skin mucus and serum lysozyme, skin mucus and serum peroxidase, alternative complement, phagocytosis, and respiratory burst activities were significantly increased with the addition of PAPP. The maximum (P ≤ 0.05) innate immune values were noted in fish fed 10 g kg− 1 PAPP. Similarly, the up-regulation of IL1, IL8, and LBP gene expressions were also detected in fish fed PAPP diets, with the maximum value was found in 10 g kg− 1 PAPP fed fish. The relative percentage of survival (RPS) of Oreochromis niloticus after the challenge test were (56.00%, 72.00%, 60.00%, and 44.00%) for the 5, 10, 20 and 40 g kg− 1 PAPP diets, respectively. Fish fed the 10 g kg− 1 PAPP supplemented diet achieved the highest (P < 0.05) survival rate against S. agalactiae. Growth and feed efficiency were outstandingly (P < 0.05) enhanced in the PAPP groups. In conclusion, PAPP can be potentially used as a feed additive in Nile tilapia culture under Biofloc system.
- Invasion genetics of the mummichog (Fundulus heteroclitus): recent anthropogenic introduction in IberiaPublication . Morim, Teófilo; Bigg, Grant R.; Madeira, Pedro M.; Palma, Jorge; Duvernell, David D.; Gisbert, Enric; Lopes Da Cunha, Regina; Castilho, RitaHuman activities such as trade and transport have increased considerably in the last decades, greatly facilitating the introduction and spread of non-native species at a global level. In the Iberian Peninsula, Fundulus heteroclitus, a small euryhaline coastal fish with short dispersal, was found for the first time in the mid-1970s. Since then, F. heteroclitus has undergone range expansions, colonizing the southern region of Portugal, southwestern coast of Spain and the Ebro Delta in the Mediterranean Sea. Cytochrome b sequences were used to elucidate the species invasion pathway in Iberia. Three Iberian locations (Faro, Cádiz and Ebro Delta) and 13 other locations along the native range of F. heteroclitus in North America were sampled. Results revealed a single haplotype, common to all invasive populations, which can be traced to the northern region of the species' native range. We posit that the origin of the founder individuals is between New York and Nova Scotia. Additionally, the lack of genetic structure within Iberia is consistent with a recent invasion scenario and a strong founder effect. We suggest the most probable introduction vector is associated with the aquarium trade. We further discuss the hypothesis of a second human-mediated introduction responsible for the establishment of individuals in the Ebro Delta supported by the absence of adequate muddy habitats linking Cádiz and the Ebro Delta. Although the species has a high tolerance to salinity and temperature, ecological niche modelling indicates that benthic habitat constraints prevent along-shore colonisation suggesting that such expansions would need to be aided by human release.
- Behavioral traits of captive short-snouted seahorse Hippocampus hippocampus, Linnaeus 1758Publication . Gristina, Michele; Pierri, Cataldo; Lazic, Tamara; Palma, JorgeStudies of behavioral traits of threatened marine species are fundamental in order to plan correct conservation strategies. This information becomes crucial to seahorses conservation, given the poor swimming skills and small home ranges of these fishes. Although information with regards to seahorse behaviors has increased in the last period, there is still a severe lack of knowledge concerning behavioral traits of the majority of Hippocampus spp. worldwide. The present study aims to present preliminary data on behaviour traits of captive H. hippocampus (short-snouted seahorse) under different conditions of habitat complexity and water temperature. In agreement with previous studies conducted on congeneric species H. hippocampus showed great thermal tolerance at least in the thermal range used in the present experiment. On the contrary, significant differences were found in behaviors adopted in the presence and absence of the algal component. However, it will be necessary to further investigate H. hippocampus behavior also in consideration of its interactions with the congeneric H. guttulatus when they occur sympatrically.
- Editorial: Syngnathid fishes: biology, ecology, physiology, conservation and innovative rearing techniquesPublication . Planas, Miquel; Gristina, Michele; Palma, Jorge; Qin, Geng; Rose, Emily; Roth, Olivia; Teske, Peter R.Syngnathids (a bony fish family that includes seahorses, pipefishes and seadragons) have unique morphological and biological traits that include fused jaws, an exoskeleton and male parental care (Ahnesjö and Craig, 2011). They are mostly found in shallow coastal areas, and their unconventional life history renders them particularly vulnerable to population depletion (Foster and Vincent, 2004). Although some species have been listed as Vulnerable, Endangered, and even Critically Endangered by the IUCN Red List of Threatened Species, many are classified as Data Deficient (DD) due to insufficient information (IUCN, 2020; Pollom et al., 2021). Therefore, further research is needed to understand their distribution, population trends and main threats. A significant portion of the research on syngnathids is relatively recent (Cohen et al., 2017; Segaran et al., 2023). This Research Topic provides 12 original research and review contributions that provide an overview of current trends in research related to the biology, physiology, ecology and conservation of syngnathids. We have gained considerable insights into syngnathid evolutionary innovation, particularly concerning the evolution of male pregnancy (Lin et al., 2016; Roth et al., 2020). The review by Parker et al. sheds light on the unique modification of the syngnathid immune system and its associations with physiology and reproduction, and highlights future research objectives.