Browsing by Author "Correia, Miguel"
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- A synthesis of European seahorse taxonomy, population structure, and habitat use as a basis for assessment, monitoring and conservationPublication . Woodall, Lucy C.; Otero-Ferrer, Francisco; Correia, Miguel; Curtis, Janelle M. R.; Garrick-Maidment, Neil; Shaw, Paul W.; Koldewey, Heather J.Accurate taxonomy, population demography, and habitat descriptors inform species threat assessments and the design of effective conservation measures. Here we combine published studies with new genetic, morphological and habitat data that were collected from seahorse populations located along the European and North African coastlines to help inform management decisions for European seahorses. This study confirms the presence of only two native seahorse species (Hippocampus guttulatus and H. hippocampus) across Europe, with sporadic occurrence of non-native seahorse species in European waters. For the two native species, our findings demonstrate that highly variable morphological characteristics, such as size and presence or number of cirri, are unreliable for distinguishing species. Both species exhibit sex dimorphism with females being significantly larger. Across its range, H. guttulatus were larger and found at higher densities in cooler waters, and individuals in the Black Sea were significantly smaller than in other populations. H. hippocampus were significantly larger in Senegal. Hippocampus guttulatus tends to have higher density populations than H. hippocampus when they occur sympatrically. Although these species are often associated with seagrass beds, data show both species inhabit a wide variety of shallow habitats and use a mixture of holdfasts. We suggest an international mosaic of protected areas focused on multiple habitat types as the first step to successful assessment, monitoring and conservation management of these Data Deficient species.
- O contexto do património arquitectónico: um projecto de investigaçãoPublication . Marado, Catarina Almeida; Correia, MiguelA par da substancial transformação do conceito de património arquitectónico, os modelos, estratégias e instrumentos que promovem a sua protecção sofreram também significativas alterações ao longo do tempo. Em simultâneo, e de forma inevitável, o contexto vem assumindo um progressivo e preponderante papel na sua salvaguarda e nos critérios que medeiam as intervenções nestes imóveis de valor patrimonial. As mais recentes cartas ou recomendações referem a importância do contexto – alargado ao conceito de “lugar” – para o significado dos bens imóveis de interesse cultural e, consequentemente, a necessidade de desenvolver instrumentos que promovam a sua conservação e gestão. Este artigo apresenta uma proposta de investigação que pretende reflectir sobre esta temática: o contexto do património arquitectónico. O objectivo final deste projecto é constituir uma plataforma crítica, que contribua activamente para a presente necessidade de reflexão sobre as Zonas Especiais de Protecção (ZEP) dos imóveis classificados, em particular sobre a sua delimitação. Este propósito assentará no desenvolvimento de três linhas de investigação: a interpretação das relações territoriais do património edificado, a inventariação e caracterização das zonas especiais de protecção existentes em Portugal e a elaboração de um estudo comparativo das diferentes experiências europeias no âmbito da protecção do contexto dos bens imóveis.
- 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.
- Effects of anthropogenic noise as a source of acoustic stress in wild populations of Hippocampus guttulatus in the Ria Formosa, south PortugalPublication . Palma, Jorge; Magalhães, Marisa Gonçalves; Correia, Miguel; Andrade, José PedroThis study evaluated the effects of underwater noise as a source of acoustic stress in the wild populations of Hippocampus guttulatus in the Ria Formosa, south Portugal. Two different scenarios of underwater noise were tested: transient motor boat sound (63.4-127.6 dB) and constant sound produced by the motor of the boat directly above the animals (up to 137.1 dB). Observations were obtained in the wild between 4 and 10 m depth throughout a 3 min period, using a video camera and a hydrophone set, and compared with a control sample. A significant increase (P < 0.05) in the respiratory rate was observed in 87% of the observed fish. Opercular movements per minute (OMPM) increased from 35.7 +/- 10 (control sample) to 41.2 +/- 15.5 after the first minute, to 45.5 +/- 13.3 after the second (both under transient sound) and to 49.7 +/- 12.5 after the third (under constant sound exposure). Differences in means between the control fish and fish observed during the second (P < 0.01) and third minute of observation (P < 0.0001) were significant. Concordantly, a significant increase (P < 0.05) in the OMPM of fish observed in the first minute and the third minute was noted. In addition to the OMPM increase, 37.5% of the animals abandoned the observation location presumably in an attempt to avoid the negative sound stimuli. The noise caused by boat traffic generated an immediate physiological response, expressed as an increase in OMPM, and a behavioural response resulting in site abandonment, which together can be considered as a negative impact on the seahorse populations. This work contributes to an increasing number of studies that have shown that boat traffic can induce ecological and environmental consequences to aquatic species. Future research should evaluate how navigation exclusion areas could have a positive impact on the seahorse populations inhabiting shallow coastal areas.
- Effects of culture density on growth and broodstock management of the cuttlefish, Sepia officinalis (Linnaeus, 1758)Publication . Correia, Miguel; Domingues, Pedro M.; Sykes, António V.; Andrade, José PedroThe effects of culture density on growth and broodstock management of the cuttlefish S. officinalis were studied. Cuttlefish used were one month old at the start of the experiment, on average; two densities were used (16 and 76 cuttlefish m 2). During the first experiment (until day 43), dead cuttlefish were replaced by individuals of similar weight. From that day onwards, no cuttlefish were replaced. No significant differences in growth and feeding rates, or food conversions were found between densities, during the first experiment. Results indicate that densities up to 76 cuttlefish m 2 are suitable for cuttlefish weighing approximately 10 g. After day 43 until first female layed eggs (second experiment), no statistical differences were found between densities for all the parameters studied with the exception of growth. In this case, cuttlefish cultured at the lower density grew more than those ones cultured at the higher density, with average weights at the start of egg laying of 137.3F21.6 and 91.8F12.3 g, respectively. This difference in growth could be explained mainly by the different culture densities and biomass associated. Fecundity obtained for cuttlefish cultured at the lower density (834 eggs female 1) was higher than for those ones cultured at the higher density (290 eggs female 1), however fertility was higher for the higher density. These results were expected, since fecundity is directly related to the size of females. Significant differences were found in fertility (hatching percentage) between densities. Mean hatching percentage was of 35.8F9.4% and 62.0F16.9% for low and high density, respectively. This difference was unexpected since we expected eggs from females cultured at lower densities to have higher quality. Mean hatchling weight was of 0.079F0.011 and 0.072F0.012 g for low and high density respectively, and significantly different. Results indicate that lower culture density promoted higher growth, larger eggs and hatchlings, but had no influence on juvenile and adult survival. On the contrary, eggs from females cultured at higher densities resulted in higher hatching rates.
- Field studies of seahorse population density, structure and habitat use in a semi-closed north-eastern Mediterranean marine area (Stratoni, north Aegean Sea)Publication . Correia, Miguel; Paulo, Diogo; Samara, Elina; Koulouri, Panayota; Mentogiannis, Vasilis; Dounas, CostasThe present study was carried out in the marine area of Stratoni, Greece, where two seahorse species are present (Hippocampus hippocampus and H. guttulatus). Two surveys were conducted (September 2016, May 2019) to gather information regarding seahorse species’ abundance, distribution and habitat characteristics. Four different seahorse natural and artificial habitat types were identified. Results revealed that the abundance of H. hippocampus was relatively high, especially at sites with artificial structures, while the presence of H. guttulatus was rare. Data collected can provide baseline information for future population assessments.
- Growth performance of the early life stages of broad-nosed pipefish, Syngnathus typhle (L.) fed different live or frozen dietsPublication . Correia, Miguel; Palma, Jorge; Andrade, José PedroThis work tested the effect of using different live and frozen feed on the growth performance of Syngnathus typhle. It was divided into two experiments. In Experiment I Artemia and Atlantic ditch shrimp (Palaemonetes varians) larvae were used as live diets, whilst in Experiment II frozen mysids Mesopodopsis slabberi and frozen P. varians were used. At the end of the first experiment juvenile pipefish grew significantly more when fed P. varians (P < 0.05) with an overall Weight Gain (WG) of 914.8 +/- 79.3% bw day(-1), compared to Artemia fed fish (WG = 683.2 +/- 14.7%). Both mean Specific Growth Rate (SGR) and survival were similar between dietary treatments and did not vary significantly (P > 0.05). In Experiment II juveniles were weaned with frozen diets but no significant differences were found between the two tested diets in all parameters tested. Final WG was 516.5 +/- 63.3% and 566 +/- 17.6%, and Feed Conversion Ratio (FCR) was 30 +/- 1.5% and 28.2 +/- 1.2% for animals fed P. varians and M. slabberi respectively. Results indicate that P. varians is an adequate diet to use during initial stages of the S. typhle life cycle and should be considered as a frozen diet for subsequent life stages of this species as an alternative to currently known natural diets.
- Habitat suitability of two flagship species, hippocampus hippocampus and Hippocampus guttulatus, in the Atlantic coast of the Iberian Peninsula - implications for conservationPublication . Peiffer, Friederike; Lima, André Ricardo Araujo; Henriques, Sofia; Pardal, Miguel A.; Martinho, Filipe; Gonçalves, Jorge Manuel Santos; Gonçalves, Emanuel J.; Correia, Miguel; Silva, Gonçalo Jorge FrancoAnthropogenic pressures on marine ecosystems are increasing worldwide, causing loss of biodiversity and ecosystem functioning, and driving species towards risk of extinction. To protect vulnerable species and habitats, Marine Protected Areas (MPAs) are increasingly established worldwide as conservation measures. Seahorses act as flagship species for coastal ecosystem conservation due to their charismatic appearance and high vulnerability to habitat degradation. Here, the habitat suitability of the two European seahorse species, Hippocampus hippocampus and Hippocampus guttulatus, was assessed along the western Iberian Peninsula, using an ensemble species distribution modelling approach. Furthermore, the coverage of their core habitat (relative habitat suitability (HS) ≥ 0.5) with MPAs was estimated. The results show that the main drivers for habitat suitability were distance to the coast, aspect of the seafloor, tidal amplitude, and temperature. However, the importance differed between the two species. The suitable habitat of H. hippocampus extended to higher distances to the coast, while H. guttulatus were mostly restricted to areas in the vicinity of the coast and facing away from the open sea (i.e., the westerly aspect of the seafloor). Furthermore, temperature contributes more to the variation in habitat suitability in H. hippocampus than in H. guttulatus. The areas with the highest habitat suitability are estuarine or inlet waters and sheltered coasts in northwestern Spain, central and south of Portugal. Both species’ core habitats are covered by about 19–20 % with implemented protected areas in Portugal. In comparison, there is less coverage for both species in Spain, with 12 % for H. guttulatus and 6 % for H. hippocampus. Besides, zones of full protection cover less than 0.5 % of the core habitat while the rest of the protected areas provide only moderate to low restrictions and do not specifically address the protection of seahorses in their management plans. The results provide useful information on the distribution and the different habitat preferences of the two species, indications for further monitoring of populations, and recommendations for efficient spatial conservation areas that can protect the species and other associated vulnerable species and habitats.
- Replacement of fish meal with crustacean meals in diets for long-snouted seahorse, hippocampus guttulatus: digestibility and growth performancePublication . Palma, Jorge; Correia, Miguel; Andrade, José Pedro Andrade; Bureau, DominiqueThis study investigated the effect of partially replacing fish meal with krill and copepod meals in inert diets co-fed with shrimp on the growth and nutrient digestibility of long-snout seahorses (Hippocampus guttulatus). A control diet (Diet 1) using raw starch and four experimental diets with similar protein (approximate to 44.8%) and energy (approximate to 15.1 MJ/kg) levels were tested. Diet 2 used fish meal as the sole protein source, while in Diets 3-5, krill and copepod meals replaced 44% of the fish meal. Seahorses fed shrimp + Diets 2-5 showed significantly higher growth rates (p < 0.05) than those fed shrimp + Diet 1, though there were no significant growth differences among Diets 2-5. Digestibility of dry matter (46.1% to 72.2%), lipids (73.3% to 85.5%), crude protein (89.8% to 95.8%), energy (82% to 92.2%), and phosphorus (28.7% to 64.4%) varied with diet, being consistently lower in seahorses fed shrimp + Diet 1. As an agastric species, H. guttulatus did not exhibit impaired digestibility for any of the tested nutrients, minerals, or energy. This study suggests that crustacean meals can effectively substitute fish meal in inert diets for this species, contributing to the sustainability and optimization of captive seahorse husbandry practices.
- Successful use of geochemical tools to trace the geographic origin of Long-Snouted Seahorse Hippocampus guttulatus raised in captivityPublication . Cabral, Ana Elisa; Ricardo, Fernando; Patinha, Carla; Silva, Eduardo Ferreira da; Correia, Miguel; Palma, Jorge; Planas, Miquel; Calado, RicardoThe global market of dried seahorses mainly supplies Traditional Chinese Medicine and still relies on blurry trade chains that often cover less sustainable practices targeting these pricey and endangered fish. As such, reliable tools that allow the enforcement of traceability, namely to confirm the geographic origin of traded seahorses, are urgently needed. The present study evaluated the use of elemental fingerprints (EF) in the bony structures of long-snouted seahorses Hippocampus guttulatus raised in captivity in two different locations (southern Portugal and Northern Spain) to discriminate their geographic origin. The EF of different body parts of H. guttulatus were also evaluated as potential proxies for the EF of the whole body, in order to allow the analysis of damaged specimens and avoid the use of whole specimens for analysis. The contrasting EF of H. guttulatus raised in the two locations allowed their reliable discrimination. Although no single body part exactly mimicked the EF of the whole body, seahorse trunks, as well as damaged specimens, could still be correctly allocated to their geographic origin. This promising forensic approach to discriminate the geographic origin of seahorses raised in captivity should now be validated for wild conspecifics originating from different locations, as well as for other species within genus Hippocampus.