The green tips of Salicornia ramosissima are used for human consumption, while, in a production scenario, the rest of the plant is considered a residue. This study evaluated the potential of incorporating salicornia by-products in diets for juvenile European seabass, partially replacing wheat meal, aspiring to contribute to their valorization. A standard diet and three experimental diets including salicornia in 2.5%, 5% and 10% inclusion levels were tested in triplicate. After 62 days of feeding, no significant differences between treatments were observed in fish growth performances, feeding efficiency and economic conversation ratio. Nutrient digestibility of the experimental diets was unaffected by the inclusion of salicornia when compared to a standard diet. Additionally, salicornia had significant modulatory effects on the fish muscle biochemical profiles, namely by significantly decreasing lactic acid and increasing succinic acid levels, which can potentially signal health-promoting effects for the fish. Increases in DHA levels in fish fed a diet containing 10% salicornia were also shown. Therefore, the results suggest that salicornia by-products are a viable alternative to partially replace wheat meal in diets for juvenile European seabass, contributing to the valorization of a residue and the implementation of a circular economy paradigm in halophyte farming and aquaculture.

Raw data on wet weight and upper thermal tolerance limits (CTMax) of the ragworm Hediste diversicolor collected at Ria de Aveiro (Portugal) and subjected to a combination of different temperatures (24, 27 and 30 ºC) and salinities (20 and 30) after 29 days of acclimation. Wet weight data was obtained post-CTMax assay.

Global projections predict significant increases in ocean temperature and changes in ocean chemistry, including salinity variations by 2100. This has led to a substantial interest in the study of thermal ecophysiology, as temperature is a major factor shaping marine ectotherm communities. However, responses to temperature may be influenced by other factors such as salinity, highlighting the relevance of multiple stressor studies. In the present work, we experimentally evaluated the thermal tolerance of the marine ragworm Hediste diversicolor under predicted global change scenarios. Organisms were subjected to an experimental trial under control (24 degrees C), and two temperature treatment scenarios (ocean warming +3 degrees C - (27 degrees C) and heat wave +6 degrees C - (30 degrees C)), combined with salinity variations (20 and 30) in a full factorial design for 29 days. Environmental data from the field were collected during 2019 and 2020. At day 30 post exposure, upper thermal limits (Critical Thermal Maximum -CTMax), thermal safety margins (TSM) and acclimation capacity were measured. Higher acclimation temperatures led to higher thermal tolerance limits, confirming that H. diversicolor features some physiological plasticity, acclimation capacity and a positive thermal safety margin. This margin was greater considering in situ temperature data from 2019 than maximum temperatures for 2020 (CTMax > maximum habitat temperature-MHT). Moreover, smaller organisms displayed higher upper thermal limits suggesting that thermal tolerance is size dependent. Ragworms subjected to higher salinity also showed a higher CTMax than those acclimated to lower salinity. However, temperature and salinity showed an additive effect on CTMax, as no significant interaction was detected. We conclude that H. diversicolor can easily acclimate to increased water temperature, independently of salinity variations. Given the key role of ragworms in food webs in estuaries and coastal lagoons, substrate bioturbation and aquaculture, this information is relevant to support conservation actions, optimize culture protocols and identify thermal resistant strains.

Extreme weather events, such as heatwaves, are becoming increasingly frequent, long-lasting and severe as global climate change continues, shaping marine biodiversity patterns worldwide. Increased risk of overheating and mortality across major taxa have been recurrently observed, jeopardizing the sustainability of ecosystem services. Molecular responses of species, which scale up to physiological and population responses, are determinant processes that modulate species sensitivity or tolerance to extreme weather events. Here, by integrating proteomic, fatty acid profiling and physiological approaches, we show that the tolerance of the intertidal ragworm Hediste diversicolor, a keystone species in estuarine ecosystems and an emergent blue bio-resource, to long-lasting heatwaves (24  vs 30 °C for 30 days) is shaped by calcium homeostasis, immune function and stability of fatty acid profiles. These features potentially enabled H. diversicolor to increase its thermal tolerance limit by 0.81 °C under the heatwave scenario and maintain survival. No growth trade-offs were detected, as wet weight remained stable across conditions. Biological variation of physiological parameters was lower when compared to molecular measures. Proteins showed an overall elevated coefficient of variation, although decreasing molecular variance under the heatwave scenario was observed for both proteins and fatty acids. This finding is consistent with the phenomenon of physiological canalization in extreme environments and contradicts the theory that novel conditions increase trait variation. Our results show that keystone highly valued marine polychaetes are tolerant to heatwaves, confirming the potential of H. diversicolor as a blue bio-resource and opening new avenues for sustainable marine aquaculture development.

The bioremediation and biomass production of organic extractive organisms (polychaetes Arenicola marina , Hediste diversicolor and halophyte Salicornia ramosissima ) was assessed in an integrated multi-trophic aquaculture (IMTA) framework. Culture trials were performed outdoors using the nutient rich effluent from a shrimp farm employing recirculated aquaculture systems. Similar bioremediation efficiencies were obtained in cultures using a single polyculture tank (1 T) or two trophic levels separated tanks (2 T; ≈ 0.3 and 0.6 m 2 operational area, respectively), with a reduction of 74–87% for particulate organic matter (POM), 56–64% for dissolved inorganic nitrogen (DIN) and 60–65% for dissolved inorganic phosphorus (DIP). Hediste diversicolor adapted well to culture conditions, reaching densities up to 5.000 ind. m −2 (≈ 78–98 g m −2 ). Arenicola marina failed to cope with water temperature that exceeded the species thermal limits, displaying a survival < 10% (20 °C often pointed as the maximum thermal threshold for this species). Productivity of S. ramosissima with 1 T was about twice that obtained with 2 T (≈ 150–170 and ≈ 60–90 g FW m −2 edible aboveground biomass, respectively). The yellowish coloration of cultured plants was likely due to the chemical oxidation and rapid sand filtration pre-treatment applied to the brackish groundwater used in the aquaculture facility, that removed iron (and probably other essential elements). Overall, 1 T design combining H. diversicolor and S. ramosissima displayed the best bioremediation performance and biomass production, while also allowing reducing in half the operational area required to implement this IMTA framework.

Raw data on survival rates, wet weight, cellular stress response, oxidative stress and energy reserves of the ragworm Hediste diversicolor collected at Ria de Aveiro (Portugal) and subjected to a combination of different temperatures (24, 27 and 30 ºC) and salinities (20 and 30) over time (14 and 28 days). The biomarkers analysed include: heat shock protein 70 kDa, total ubiquitin, catalase, superoxide dismutase, glutathione-S-transferase, total antioxidant capacity, lipid peroxidation, glucose, glycogen, total protein and total lipids.

Polychaetes can be successfully employed to recover essential fatty acids (EFA) from wasted uneaten aquafeeds present in aquaculture effluents. The optimization of the timeframe required to produce premium ragworms (Hediste diversicolor) biomass rich in EFA is paramount to make available to the aquafeeds industry another alternative ingredient to fish meal and fish oil. The present study aimed to evaluate the potential enrichment of ragworms fatty acid (FA) profile when fed a commercial aquafeed during 10, 20, and 40 days (D10, D20, and D40) under different combinations of water temperature (20 and 25°C) and salinity (15, 20, and 25). Total FA incremented progressively overtime, with D40 polychaetes exhibiting average values ranging between 70 and 90 μg mg–1 DW. The average values of n-6 FA ranged between 13 and 17 μg mg–1 DW, while that of n-3 FA varied between 17 and 19 μg mg–1 DW at D40. No significant differences were found in the FA profile of H. diversicolor cultured under different combinations of temperature and salinity. The FA profile of cultured polychaetes exhibited between 28 and 31% dissimilarity from that of wild conspecifics and displayed a higher content of two essential n-3 FA: eicosapentaenoic (20:5 n-3, EPA) and docosahexaenoic acids (22:6 n-3, DHA) (values ranging between 9.6–11.2% and 4.3–5.0% of total FA, respectively). A higher similarity in FA profile was recorded between D40 polychaetes and aquafeed than with initially stocked or wild specimens. Palmitic (16:0), oleic (18:1 n-9), linoleic (18:2 n-6), eicosadienoic (20:2 n-6), EPA (20:5 n-3), and DHA (22:6 n-3) were the FA whose concentration exhibited the highest increment. Evidence of de novo FA biosynthesis was observed through the formation of some FA that were neither present in the initially stocked biomass, nor in the aquafeed supplied, such as 5,11-eicosadienoate (Δ 5,1120:2), 7,13,16-docosatrienoate (Δ 7,13,1622:3), dihomo-gamma-linolenic (20:3 n-6), eicosatrienoic (20:3 n-3) and eicosatetraenoic (20:4 n-3) acids. A plateau of total FA, n-6, and n-3 FA was not reached over the study period. Overall, the present study highlights the potential of H. diversicolor as an extractive species for integrated multi-trophic aquaculture (IMTA) applications.

Global change projections predict significant impacts on the aquaculture sector leading to a substantial interest in the study of species' ecophysiological responses to increased temperature and shifting salinities. Here, we experimentally evaluated shifts on the fatty acid (FA) profiles of the ragworm Hediste diversicolor under global and local ocean change drivers. This polychaete is a suitable extractive organism for integrated multi-trophic aquaculture (IMTA) designs, as it maximizes the use of otherwise wasted nutrients present in particulate organic matter of farm effluents. Ragworms were collected from intertidal mudflats and subjected to an experimental trial of 28 days under control (24 degrees C), warming (27 degrees C) and heatwave (30 degrees C) scenarios combined with salinity variations (20 and 30) in a full factorial design. Individuals were sampled after 14 and 28 days of exposure (D14 and D28 respectively) for FA profile analysis. Interactions between temperature x day and salinity x day modulated ragworms' fatty acid profiles. Overall, an increase in different FA classes, as well as in En-3 UFA, En-6 UFA and essential fatty acids (EFA) was detected over time in polychaetes exposed to salinity 30, contrary to what was observed in salinity 20. This suggests that salinity 30 is an optimal condition for H. diversicolor FA enrichment. At this salinity, fatty acids from n-3 and n-6 families remained stable at 24 degrees C and 27 degrees C, with a decrease being detected at 30 degrees C (after 14 days of exposure), possibly related to changes in the lipid composition of cell membranes to maintain homeostasis. However, after 28 days, no differences were detected, suggesting that polychaetes can acclimate to elevated temperatures when they are in optimal salinity conditions. In contrast, if an extreme warm event (30 degrees C) is combined with low salinity (20), all FA classes increase at day 14 and HUFA class remain elevated after 28 days, while En-3 UFA, En-6 UFA, ARA, EPA and DHA decrease, suggesting their potential role in osmotic balance and membrane fluidity. Still, if ragworms are grown at low salinity and the increase in temperature is only moderate, En-3 UFA, En-6 UFA, ARA, EPA and DHA increase. This study shows that heatwaves can have an impact on H. diversicolor aquaculture, especially under low salinity conditions, by decreasing EFA. Risk assessment and adaptation strategies need to be implemented into aquaculture practices to mitigate the impacts of global change on the nutritional profile of farmed species and their overall commercial value.

Estuarine systems are critical transition zones influenced by sea, land and freshwater. An array of human activities impacts these areas leading to multiple-stressor interactions. Temperature and salinity are among the most relevant drivers in estuaries, shaping species growth, reproduction and distribution. However, few studies provide an overview of cellular rewiring processes under multiple-stressor environments. Here, we tested how salinity could shape the response of ragworms Hediste diversicolor, an important bioindicator and commercial species, to elevated temperature. We exposed polychaetes to three temperatures for a month, simulating control, ocean warming and heatwave conditions (24, 27 and 30 °C, respectively) combined with two salinities (20 and 30). We quantified whole-organism performance (wet weight gain and survival), along with cellular stress response (CSR) and energy reserves of worms after 14 and 28 days of exposure. Significant three-way interactions between temperature, salinity and exposure time show the non-linearity of molecular responses. Worms at a salinity of 20 were more sensitive to warming than worms exposed to a salinity of 30. The combination of high temperature and low salinity can act synergistically to induce oxidative stress and macromolecular damage in worm tissues. This finding was supported by an induction of the CSR, with a concomitant decrease of energy reserves, pointing towards a metabolic compensation strategy. However, under a higher salinity (30), the need for a CSR upon thermal challenge was reduced and energy content increased with temperature, which suggests that environmental conditions were within the optimum range. Heatwaves striking low-salinity areas of estuaries can therefore negatively impact the cellular physiology of H. diversicolor, with greater metabolic costs. However, extreme stress levels were not reached as worms incremented wet weight and survival was high under all conditions tested. Our findings are important for the optimization of ragworm aquaculture and adaptive conservation strategies of estuarine systems.

Polychaetes can be successfully employed to recover otherwise wasted nutrients present in particulate organic matter (POM) of aquaculture effluents. The present study describes the fatty acid (FA) profile of four different polychaete species cultured in sand filters supplied with effluent water from a marine fish farm. The FA profile of cultured and wild Hediste diversicolor was compared and revealed a ≈ 24.2% dissimilarity, with cultured biomass displaying a higher content in two essential n -3 highly unsaturated FA (HUFA) (EPA [20:5 n -3] and DHA [22:6 n -3]—eicosapentaenoic and docosahexaenoic acid, respectively). The comparison of the FA profile of cultured H. diversicolor with that of other polychaete species whose larvae successfully settled on the sand filters ( Diopatra neapolitana , Sabella cf. pavonina and Terebella lapidaria ) revealed that their FA profile, which is here described for the first time, displayed high levels of EPA and DHA (≈ 1.5–4.8 and 1.0–1.1 µg mg −1 DW, respectively). The highest concentration of total FA per biomass of polychaete was recorded in H. diversicolor and T. lapidaria , with both species being the ones whose FA profiles revealed a lowest level of dissimilarity and more closely resembled that of the aquafeed used in the fish farm. In the present work it was demonstrated that it is possible to produce polychaetes biomass with high nutritional value through an eco-design concept such as integrated multi-trophic aquaculture (IMTA). Indeed, this framework promotes a cleaner production and, in this specific case, allowed to recover essential fatty acids that are commonly wasted in aquaculture effluents.

Polychaete assisted sand filters (PASFs) allow to combine a highly efficient retention of particulate organic matter (POM) present in aquaculture effluent water and turn otherwise wasted nutrients into valuable worm biomass, following an integrated multi-trophic aquaculture (IMTA) approach. This study evaluated the bioremediation and biomass production performances of three sets of PASFs stocked with ragworms (Hediste diversicolor) placed in three different locations of an open marine land-based IMTA system. The higher organic matter (OM) recorded in the substrate of the systems which received higher POM content (Raw and Df PASFs – filtered raw and screened by drum filter effluent, respectively) likely prompted a superior reproductive success of stocked polychaetes (final densities 2–7 times higher than initial stock; ≈1000–3000 ind. m−2). Bioremediation efficiencies of ≈70% of supplied POM (≈1.5–1.8 mg L−1) were reported in these systems. The PASFs with lower content of OM in the substrate (Df + Alg PASFs – filtered effluent previously screened by drum filter and macroalgae biofilter) differed significantly from the other two, with stocked polychaetes displaying a poorer reproductive success. The PASFs were naturally colonized with marine invertebrates, with the polychaetes Diopatra neapolitana, Terebella lapidaria and Sabella cf. pavonina being some of the species identified with potential for IMTA.

Turbot, Scophthlalmus maximus, is a Pleuronectiformes fish that occurs in northeast Atlantic along the European coast and in the Mediterranean Sea and is produced in aquaculture since the last quarter of the twentieth century. During a survey conducted in a turbot fish farm nodular formations were occasionally observed in several organs, especially in the kidney and in the spleen. Microscopic observations showed that these nodules contained acid-fast bacilli. The molecular identification of the isolated bacteria conducted to the Mycobacterium genus. Although no abnormal mortalities were evident morbidity was observed. The normal development and welfare of infected fish decrease and the condition factor, the haematocrit and the haemoglobin concentration in blood decreases significantly with the increase of nodules abundance.

Journal of Fish DiseasesVolume 34, Issue 12 p. 937-938 Short Communication Polycystic liver in farmed turbot, Scopthalmus maximus (L.) D Jeronimo, D Jeronimo Faculdade de Ciências, Universidade do Porto, Departamento de Biologia, R. do Campo Alegre, Porto, PortugalSearch for more papers by this authorC Cruz, C Cruz Faculdade de Ciências, Universidade do Porto, Departamento de Biologia, R. do Campo Alegre, Porto, Portugal CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas, Porto, PortugalSearch for more papers by this authorA Saraiva, A Saraiva Faculdade de Ciências, Universidade do Porto, Departamento de Biologia, R. do Campo Alegre, Porto, Portugal CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas, Porto, PortugalSearch for more papers by this author D Jeronimo, D Jeronimo Faculdade de Ciências, Universidade do Porto, Departamento de Biologia, R. do Campo Alegre, Porto, PortugalSearch for more papers by this authorC Cruz, C Cruz Faculdade de Ciências, Universidade do Porto, Departamento de Biologia, R. do Campo Alegre, Porto, Portugal CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas, Porto, PortugalSearch for more papers by this authorA Saraiva, A Saraiva Faculdade de Ciências, Universidade do Porto, Departamento de Biologia, R. do Campo Alegre, Porto, Portugal CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas, Porto, PortugalSearch for more papers by this author First published: 18 October 2011 https://doi.org/10.1111/j.1365-2761.2011.01309.xCitations: 5 A Saraiva, Faculdade de Ciências, Universidade do Porto, Departamento de Biologia, Rua do Campo Alegre, Edifício FC 4, 4169-007 Porto, Portugal(e-mail: [email protected]) Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References Bettini G., Mandrioli L. & Morini M. (2003) Bile duct dysplasia and congenital hepatic fibrosis associated with polycystic kidney (Caroli syndrome) in a rat. Veterinary Pathology 40, 693–694. Bruno D.W. & Ellis A.E. (1986) Multiple hepatic cysts in farmed Atlantic salmon, Salmo-salar L. Journal of Fish Diseases 9, 79–81. Bruno D.W. & Poppe T.T. (1996) A Colour Atlas of Salmonid Diseases. Academic Press, London. Ferguson H.W. (2006) Systemic Pathology of Fish: A Text and Atlas of Normal Tissues in Teleosts and their Response in Disease. Scotian Press, London. Froese R. & Pauly D. (2010) FishBase World Wide Web electronic publication. http://www.fishbase.org, version (09/2010) Glawischnig W. & Bago Z. (2010) Polycystic liver disease in senile chamois (Rupicaprae rupicaprae). Journal of Wildlife Diseases 46, 669–672. Krotec K., Meyer B.S., Freeman W. & Hamir A.N. (1996) Congenital cystic disease of the liver, pancreas, and kidney in a nubian goat (Capra hircus). Veterinary Pathology 33, 708–710. McKenna S.C. & Carpenter J.L. (1980) Polycystic disease of the kidney and liver in the cairn terrier. Veterinary Pathology 17, 436–442. Picone J., Williams J.F., Leid W. & Fay L.D. (1981) Polycystic liver in four white-ailed deer. Journal of Wildlife Diseases 17, 395–400. Roberts R.J. (2001) Fish Pathology. W. B. Saunders, London. Taylor P., Smith C.E. & Blair M.J. (2009) Polycystic lesions in the liver of the white sturgeon. Journal of Aquatic Animal Health 21, 57–59. Woo P.T.K., Bruno D.W. & Lim L.H.S. (eds) (2002) Diseases and Disorders of Finfish in Cage Culture. CABI Publishing, New York. Citing Literature Volume34, Issue12December 2011Pages 937-938 ReferencesRelatedInformation

Turbot Scophthalmus maximus (Linnaeus, 1758) referred many times as Psetta maxima junior synonym is a Pleuronectiformes fish that has been produced in aquaculture since the last quarter of XX century. One decisive factor to the maintenance and development of this economically important production is the increase of the knowledge of the most important diseases affecting turbot. The most deleterious infections on turbot culture in Iberian Peninsula are caused by bacteria and parasites. During a survey conducted during a 10month period (September 2009 to June 2010) in a Portuguese turbot intensive fish farm the cosmopolitan ectoparasite dinoflagellate Amyloodinium ocellatum was detected in 87.2% of turbot when water temperatures ranged from 18.2 to 19.7°C (temperate season) and 44.4% when water temperature ranged from 16 to 18.1°C (cold season). In both seasons infections levels were light and did not cause abnormal mortality. Histological sections revealed the occurrence of few scattered trophonts that insert the attaching disc into host cells causing vacuolar degeneration, focal hyperplasia and necrosis on gill epithelium. In this study it was stated that A. ocellatum was present and can multiply along all year around in temperate regions without causing epizootic problems when infection levels is low. However surveillance should be performed in spring and summer time in order to avoid proliferation of parasites and associated fish mortalities. This is the first report of the occurrence of A. ocellatum in a turbot fish farm.