Optimisation of captive breeding of the lumpfish Cyclopterus lumpus for sea lice control in salmon farming.
Conference Paper: Aquaculture Europe 2015, Rotterdam.
With an annual value of £588 M, the Atlantic salmon farming sector is the UK's largest single food exporter, directly employing 1,086 people in 257 farms, located in rural communities in Scotland. Scottish salmon is exported to 60 countries and has built a reputation for quality, sustainability and welfare, with Protected Geographical Indication status and 65% of fish being accredited under RSPCA Freedom Food Standards. However, plans for growth are being hampered by the challenge from sea lice which is estimated to cost the economy in excess of £30 M annually. In addition to direct costs associated with sea lice control, there is the potential for production losses associated with reduced growth, immunosuppression, and impaired welfare, all of which would have a negative effect on sustainability and potential for industry growth. The UK is restricted in the number of anti-sea lice medicines that can be used and current therapeutants are becoming less effective. Cleaner fish are a greener alternative to the use of these medicines, and ballan wrasse (Labrus bergylta) are being successfully farmed. Wrasse are very efficient at delousing salmon but they perform less well in winter. Lumpfish (Cyclopterus lumpus) prefer colder water and the two species will work well together in a complementary delousing strategy. To meet industry demands, ~10M cleaner fish of both species will be needed by 2020. We began in late 2014 a joint project aimed at developing and optimizing the sustainable farming of lumpfish, and its commercial deployment. To date + 1 million alevins have been produced from 120 females, of which 38 females were released back to the wild while a similar number are being reconditioned in captivity. Delousing of wild broodstock has been achieved by freshwater baths on entry followed by quarantine. Caligus sp., Gyrodactylus sp., and opportunistic ciliates have been observed and these were treated with Flukesolve, Licesolve and formalin baths, respectively. Lesions on adults have been treated with Topical Orabase. Egg husbandry has consisted of flattening and shaping egg masses to avoid 'dead areas' and, in the absence of natural male care, this appears to increase hatch rates, which is also enhanced by upwelling hopper incubators. Pilot results also indicate that keeping egg masses from single females in separate incubators facilitates husbandry and assists with traceability, while regular Pyceze treatment are also beneficial. Degumming trials involving alcalase, trypsin and milk have yielded inconclusive or mixed results and require further research. Larva are reared at densities ranging from 20 to 100 larvae/L starting with a small flow (c. 1L/min) rising to 15L/min after larvae become more active. Initial weaning rations were 10% biomass, and these were then reduced to 5% biomass after three weeks consisting of Artemia and dry feeds 250-350µm in size. The farming of lumpfish represents a unique opportunity to develop a new aquaculture species, create jobs in remote areas, and achieve greater sustainability in salmon farming. There are several challenges. For example, it is proving difficult to obtain quality gametes consistently, as broodstock become easily stressed during transport and handling, fry survival is variable, and no broodstock has been reconditioned to spawn over more than one breeding season. We have identified several production bottlenecks where innovative research is needed to farm lumpfish sustainably, namely (1) Optimization of reproduction and juvenile production, (2) Traceability and genetic characterization, and (3) Disease screening, biosecurity and monitoring during deployment.
Untersuchungen zur biotechnologischen Kultivierung von Schwämmen - Massenbilanzierung bei Aplysina aerophoba.
Dissertation, Universität Karlsruhe (TH). Fakultät für Chemieingenieurwesen und Verfahrenstechnik, 2008.
130 Seiten. Universitätsverlag Karlsruhe 2009. Print on Demand. ISBN: 978-3-86644-342-6.
In den letzten Jahren wurde der marine Lebensraum als Quelle zahlreicher neuer Naturstoffe mit besonderen biologischen Eigenschaften, vor allem für pharmazeutische Anwendungen, erforscht. Über 18.000 neue Naturstoffe aus marinen Organismen wurden beschrieben. Schwämme (Porifera) stellen dabei mit etwa 6.700 beschriebenen Substanzen die wichtigste Quelle dar. Die meisten bioaktiven Naturstoffe erreichen jedoch nur die präklinische bzw. erste klinische Phase, da in der Regel nicht ausreichend Substanzmenge zur Verfügung stehen, um weiterführende Untersuchungen durchzuführen. Gründe sind die geringen Konzentrationen der Naturstoffe im Schwammgewebe in Kombination mit geringen natürlichen Ressourcen an Schwammbiomasse. Die Alternative durch chemische Synthese an ausreichend Substanzmenge zu gelangen scheitert oft aufgrund der komplexen Molekülstrukturen. Ein Ansatz dieses Nachschubproblem zu ösen ist die biotechnologische Produktion von Schwammbiomasse unter definierten und kontrollierten Bedingungen. Die Strategie, die zur Etablierung einer erfolgreichen biotechnologischen Kultivierung von Schwämmen verfolgt wurde, bestand darin, einen geeigneten Modellorganismus zu wählen, der pharmakologisch interessante Sekundärmetabolite produziert sowie Kulturbedin-gungen zu entwickeln, die das dauerhafte Halten gesunder Schwämme unter Aquarienbedingungen ermöglicht. Als Modellorganismus wurde der leuchtend gelbe Schwamm Aplysina aerophoba aus der Klasse der Demospongiae gewählt. Die Kriterien, die zur Auswahl dieser im Mittelmeer weit verbreiteten Art führten, waren ihre gut untersuchte Naturstoffchemie, die gute Verfügbarkeit durch die Kooperation mit dem Institut 'Ruder Boškovic' und die ergleichsweise guten Kenntnisse ihrer ökologischen Ansprüche. Ihr Vorkommen in geringen Wassertiefen zwischen einem und zwanzig Metern erleichterte das Sammeln. Erste positive Erfahrungen in Aquarienkultur sind dokumentiert.
Paddlefish (Polyodon spathula) in Europe: An aquaculture species and a potential invader.
Journal of Applied Ichthyology 35 (1): 267-274. https://doi.org/10.1111/jai.13672
The paddlefish (Polyodon spathula) was first introduced to Europe in 1974, mainly due to its potential for rearing in natural polyculture ponds and large temperate reservoirs. The information on the history of paddlefish aquaculture efforts in Europe is scarce, as well as data on current paddlefish aquaculture status and trends. In addition, there is a lack of data on its presence and potential establishment in the wild, while its invasive potential and associated risks and impacts are largely unknown. In order to evaluate its current status in Europe, we conducted a survey among scientists, aquaculture producers and other stakeholders, and reviewed literature and data on the Internet. Based on the results obtained, we discuss the potential and the challenges in European paddlefish aquaculture development, and analyze paddlefish invasive potential and risks associated with its naturalization. Paddlefish aquaculture is well established only regionally in Europe, but offers relatively high potential for further development in pond farms. Nevertheless, future development will require careful planning, especially regarding market development and improved marketing strategies. While paddlefish likely represents a low‐risk invader, improved control and reporting on trade and intentional and unintentional releases will be required. Given the lack of knowledge on potential impacts following its introduction, due caution seems highly advisable.
Feeding preferences of the dusky grouper (Epinephelus marginatus, Lowe 1834) larvae reared in semi-intensive conditions: A contribution addressing the domestication of this species.
Aquaculture 289 (2009): 289–296.
Despite research efforts addressing artificial propagation, dusky grouper aquaculture still relies onexperimental trials owing to the low survival rates of larvae and juveniles, thus rendering mass rearing difficult to attain. Although some authors suggested that the preys offered to the early larval stages represent the major problem facing the rearing of all grouper species, very little information is available in literature on larval development and the behaviour of dusky grouper. The objective of this study was to investigate the trophic preferences of larval stages of the dusky grouper by rearing using a semi-intensive technology. Larvae were reared in pilot scale mesocosms (60 m3) from 3 to 35 days post hatching. The rearing system was supplied with wild zooplankton collected in a natural coastal lagoon in order to augment the chances of satisfying the larvae's feeding requirements; the feeding preferences were analyzed during ontogenesis. The relationship between mouth gape and dimensions of preys, considered as 3-D objects, was investigated to identify possible critical factor. The results of this study suggested a sequence of suitable food items from the beginning of exogenous feeding until day 35 post hatching. In particular, dusky grouper larvae actively select copepod nauplii in the size range between 2 and 12 mm in TL, and Artemia salina nauplii for TL larger than 9 mm. The rearing approach applied seemed to be promising. Indeed, while previous rearing trials of dusky grouper failed within ten days or finished at 30 days post hatching with a lower percent of survivors, this paper reports the best survival rate reported for this species (10%±7.0 survivors at 35 days post hatching). Finally, mouth width was observed to be the limiting factor in the selection of prey, while the smallest prey size plays a critical role in determining ingestion. Our results contribute to clarifying some aspects of the larval ecology of this species, furnishing some suggestions for its cultivation.
Natural spawning, early development and first feeding of the semicircle angelfish [Pomacanthus semicirculatus (Cuvier, 1831)] in captivity.
Aquaculture Research 40 (9): 1019-1030. https://doi.org/10.1111/j.1365-2109.2009.02192.x
Successful natural spawning of Pomacanthus semicirculatus in captivity from 11 September to 18 October, 2006 is described for the first time. Each female laid an average of 230 000 ( sic ?!) eggs during the spawning period. Fertilized eggs were spherical, transparent and buoyant and had a mean diameter of 0.61 ± 0.03 mm (mean ± SD). Embryonic development lasted 18–21 h at 28.5 °C. Newly hatched larvae were 1.35 ± 0.02 mm in total length (TL) with 27 (12+15) myomeres and had an oil globule in the ventroposterior area of the yolk sac. Larvae completed yolk absorption within 3 days post hatching at 2.37 ± 0.05 mm TL. Larvae were fed either 100% microalgae (Nannochloropsis sp.), 100% s‐type rotifers (Brachionus rotundiformis), 100% dinoflagellates (Gonyaulax sp.) or different combinations of the three (50%:50%:0%, 30%:35%:35%) to determine the effect of live feed on the survival rate. The survival was significantly (P<0.001) better in larvae fed a combination of diets (30%: 35%: 35%) than others. These results indicate that P. semicirculatus is a potential species for captive‐breeding programmes and the use of a combination of diets (microalgae plus s‐type rotifers and dinoflagellates) may be a suitable first food for fish larvae.
Culture of coral reef fishes.
Austasia Aquaculture: 11 (3), August/September 1997: 56–59.
Over the past couple of years, a number of differ-ent coral reef fish species have been successfully spawned and reared at James Cook University ,with relatively high rates of survival. A list of these species is shown in Table 1 (see next page). Some ofthe species listed have been spawned, but the larvae have not yet been reared.
Erfolgreich nachgezogen wurden:
- Amphiprion melanopus
- Amphiprion percula
- Premnas biaculeatus
- Neopomacentrus bankieri
- Pomacentrus amboinensis
Oceanic Institute Achieves Breakthroughs In Culture Technology For Yellow Tang.
Global Aquaculture Advocate (January February 2013): 82-84.
The culture of yellow tang represents a considerable economic opportunity and critical conservation strategy in coral reef ecosystem protection. The Oceanic Institute is working to establish aquaculture techniques to reduce the capture of wild yellow tang. Despite bottlenecks, improvements in broodstock holding systems and dietary regimes are raising egg output and quality. Specialized larval-rearing tanks enable the generation of large numbers of larvae through the critical first-feeding period. Refined lighting and equipment are leading to more consistent feeding.