Scolding J.W.S.,University of Swansea |
Powell A.,University of Swansea |
Boothroyd D.P.,The National Lobster Hatchery |
Shields R.J.,University of Swansea
Aquaculture | Year: 2012
The fishery for the European lobster, Homarus gammarus has declined in recent years and has subsequently impacted on local socio-economics and ecology at wider scales. This has led to the formation of hatcheries (restocking wild populations with juveniles) and more recently, an interest in land based farms (ongrowing of juveniles to an edible size for direct consumption). To optimise the success of lobster rearing, ozone was investigated as a sustainable, scalable antibacterial treatment to assist water quality management and hence survival of captive lobsters at larval and post larval (PL) stages. Larval lobsters were exposed to constant ozone at a candidate concentration (400. mV, ca. 15. ppb) in a number of replicate upwelling hopper systems in five repeated experiments. At intermediate sampling points during larval rearing, ozone treatment resulted in significantly enhanced survival while Vibrio sp. bacterial load was significantly reduced in ozone treated larvae and culture water compared to controls. However, larval length and weight declined towards the end of the five repeated 18. day trials, potentially due to the effects of ozone on water chemistry and hence larval nutrition and physiology. To understand if ozonation had longer term effects on PL after metamorphosis, groups of ozonated and unozonated larval recruits were placed in separate control and constantly ozonated raceways to create four treatments. Ozone did not reduce growth rate in PL exposed to ozone at any life stage. With both "double" treatments, survival was similar and approximately average considering all four treatments, was elevated in lobsters ozonated as PL only and reduced in lobsters ozonated as larvae only. © 2012 Elsevier B.V.
Daniels C.L.,The National Lobster Hatchery |
Daniels C.L.,University of Plymouth |
Merrifield D.L.,University of Plymouth |
Ringo E.,University of Tromsø |
Davies S.J.,University of Plymouth
Aquaculture | Year: 2013
The effects of dietary applications of a commercial probiotic (Bacillus spp.) and prebiotic (mannan oligosaccharides [MOS]), used singularly and combined (i.e. synbiotic), on larval survival, growth, intestinal microbial communities and stress resistance of larval European lobster, Homarus gammarus, were assessed. Larvae were reared in green water culture for 12days from hatch until metamorphosis to zoea III. Un-supplemented Artemia nauplii (control) or Artemia nauplii enriched with probiotics (Bacillus spp. 100mgl-1), prebiotic (MOS 12mgl-1) or synbiotics (100mgl-1 Bacillus spp.+MOS 12mgl-1) were each fed to 3 replicate groups of zoea I lobsters for 12days. The effects on gut microbiota were assessed using culture-dependent methods at 1, 7 and 12days post-hatch (dph) and PCR-DGGE at 1 and 12dph. PCR-DGGE was also used to assess microbial communities of the live feeds. Carapace length and weight of five H. gammarus from each replicate was recorded on 1, 7, and 12dph and survival to zoea III was recorded. A low salinity stress test was used as a measure of organism fitness at day 12.After 12. dph, H. gammarus larvae fed experimental treatments had significantly (P<. 0.02) improved weight, carapace length and weight gain, compared to larvae fed control treatments. Survival to 12. dph was elevated by all treatments and was significantly (P<. 0.001) increased for the Bacillus and MOS fed larvae. Salinity stress tolerance was greatest in larvae fed Bacillus although all experimental treatments produced enhanced tolerance to salinity stress in comparison to larvae fed control treatment. Culture-dependent analysis of the gut microbiota of larval lobsters demonstrated the colonisation of Bacillus spp. in larvae fed probiotic or synbiotic enriched live feeds. There was also a reduction in Vibrio levels in certain biotic fed larvae and live feed treatments. PCR-DGGE revealed that the number of observed taxonomical units (OTUs), species richness and species diversity increased in zoea III lobsters fed probiotic, prebiotic and synbiotic. Subsequently, the microbial profiles were dissimilar to the control group with the synbiotic group showing the greatest dissimilarity to the control (36.54. ±. 2.54%). The similarity between bacterial communities associated with Artemia and zoea III larvae was highest in the Bacillus treatments (53.86%). The present study demonstrates the benefit of applying dietary supplementation of Bacillus, MOS and Bacillus+. MOS on the GI microbiota of lobster larvae which subsequently improved growth performance and stress tolerance. © 2013 Elsevier B.V.
Daniels C.L.,The National Lobster Hatchery |
Wills B.,The National Lobster Hatchery |
Wills B.,University of Exeter |
Ruiz-Perez M.,The National Lobster Hatchery |
And 3 more authors.
Aquaculture | Year: 2015
This three year field investigation consisted of three discrete experiments, examining six potential sites for rearing the European lobster (Homarus gammarus) around the Cornish coast (U.K.). Sea-based container culture (SBCC) systems were deployed, varying site, year, depth, shelter and pre-fouling, to test effects on growth and survival of juvenile H. gammarus. Site and depth were examined between May-August 2011 at two sites off the South coast. One estuarine (River Fal: RF) and one sea-based (St. Austell Bay: SA) site were assessed with containers suspended at either 2 or 8 m depth. Greatest survival was found at the SA site (56%) compared to RF (25%), with the greatest growth (specific growth rate: SGR 3%, live weight gain: LWG 0.4. g and carapace length gain: CLG 4.5 mm) also achieved at SA. Depth did not affect juvenile development. Between May and August 2012, one estuarine (Fowey: F) and two sea-based (SA and St. Mawes: SM) sites on the south coast were selected to assess the effect of site and shelter. SM showed the highest survival (93%). Growth and survival were not affected by the presence of a shelter. From August to December 2013, three sites off the north and south coasts were selected to assess the effect of site, depth, pre-fouling and feed availability. Sea-based (Port Quin Bay: PQ, Wave Hub: WH and SA) sites were assessed, with containers submerged at either 3 or 10 m above the sea bed (PQ 7-14 m, WH 42-49 m depth at chart datum). Survival did not significantly differ between sites (61-86%), but growth at the PQ site (LWG 0.7 g; carapace length gain: CLG 6.1 mm) was significantly greater than at all other sites (LWG 0.3-0.4 g; CLG 2.5-3.6 mm). Depth did not affect juvenile development. Pre-fouling reduced growth at all sites. Feed availability varied between sites with PQ showing the greatest taxonomical units. Variations between years were also shown between 2011 and 2013 at the SA site. SBCC systems show potential for culturing H. gammarus juveniles compared to hatchery controls (survival ≤ 46%), acting as a transition step between hatchery rearing and release for stocking purposes. The importance of site selection and between year variations is highlighted as important factors to consider for larger scale assessment of aquaculture potential. Statement of relevance: This work presents the culmination of three discrete studies between 2011 and 2013 that investigated the use of sea based container culture (SBCC) systems for rearing European lobster (H. gammarus) juveniles at various sites around South West England. This is a relatively novel field and the first study of its kind to consider sites around the South West of England and also to quantitatively assess potential feed species. The main findings of this work identify the importance of site selection, deployment and container structure. With an ever increasing demand for protein, there needs to be efforts to relieve pressure on natural fishing stocks. This study not only highlights the potential for SBCC to provide improved stock enhancement processes but also discusses the potential for aquaculture of this currently unexploited species.Juvenile culture is one of the bottlenecks for the development of lobster culture due to high unit cost of production, high mortality rates due to cannibalism within intensive culture systems and long development times, and as such we feel that this work is extremely timely and relevant. This manuscript will not only contribute to the understanding of how SBCC systems can be employed, but also adds to our understanding of the requirements of the species. Therefore, this work is of significant interest to those involved in the culture of lobsters and marine animals generally. © 2015 Elsevier B.V..
Middlemiss K.L.,University of Exeter |
Daniels C.L.,The National Lobster Hatchery |
Urbina M.A.,University of Exeter |
Wilson R.W.,University of Exeter
Aquaculture | Year: 2015
Bacterial pathogens are a leading cause of disease in hatchery aquaculture systems and preventative methods such as use of probiotics as feed supplements and water additives are well documented. However, comparisons between the effectiveness of using probiotic water additives over traditional biocontrol methods are less understood. This study assessed the combined effects of ultraviolet (UV) irradiation, O3 (ozone) and Bacillus spp. as a water additive (probiotic), in the culture of European lobster (Homarus gammarus) in a semi-closed recirculation system. Larvae were categorised as zoea stages I-III, megalopa (stage IV) and juvenile (stage V) onwards. Stage I larvae were assigned to one of six treatment groups consisting of 1) O3, 2) probiotic, 3) probiotic+O3, 4) probiotic+O3+ UV, 5) O3+UV, or 6) probiotic+UV, for 18days. During stages I-V, growth was measured on 1, 6, 11, 18, 24, and 31dph (days post hatch), and survival was measured on 1, 18, 24 and 31dph. Bacterial counts of pathogenic Vibrio spp. in culture water were measured at 1, 4, 9, 14, and 18dph. Lobsters were also exposed to a physiological fitness test (low salinity challenge) at stage IV, 7days post treatment. Results showed that O3 is comparatively more beneficial than probiotic with increased LWG (live weight gain) in the O3 treatment over probiotic between stage IV and V (>5mg). Survival rates were ~10% higher in the O3 treatment group than probiotic treatment group on day 18, then ~5% and ~4% higher on days 24 and 31. Lobster biomass on day 18 was ~60% higher in the O3 treatment than probiotic treatment and 116% higher on day 31. Total Vibrio spp. present in the O3 treatment was 0.05% of the total in the probiotic treated culture water (day 18). Results between UV treatment groups showed significantly lower numbers of Vibrio spp. present in probiotic+O3+UV culture water 4dph than O3+UV (~10 fold higher) or UV+probiotic (~15 fold higher) and by day 18 probiotic+O3+UV was significantly higher than O3+UV (~8 fold higher). Osmoregulatory challenge test resulted in no significant differences in physiological fitness between any treatment groups. The present study shows the effectiveness of O3 in aquaculture facilities for control of pathogens in the rearing of European lobster over either a probiotic water additive (at 3.75×107CFUsL-1) or UV irradiation. © 2015 Elsevier B.V.
Neenan S.T.V.,University of Exeter |
Hodgson D.J.,University of Exeter |
Tregenza T.,University of Exeter |
Boothroyd D.,The National Lobster Hatchery |
Ellis C.D.,University of Exeter
Aquaculture Research | Year: 2015
Assessments of stock enhancement programmes for European lobsters (Homarus gammarus) require mark-recapture analysis of stocked individuals. However, established tag technology is deemed unsuitable for extensive use by many current lobster hatcheries, particularly upon the early juvenile stages. We tested the suitability of fluorescent Visible Implant Elastomer (VIE) tags for use in 5-month-old juvenile lobsters. Three treatment groups comprising 348 cultured lobsters in total were used to examine survival, growth and tag retention, and to assess mobility, shelter use and moulting behaviours. Tagging had no significant effect on lobster survival, growth, mobility, shelter use or moult frequency. Survival over 7 weeks was 75% among lobsters tagged with two elastomers, 76% in those with one elastomer and 74% among untagged controls. Mortality during moulting did not increase in tagged (6%) compared to untagged lobsters (9%). We found no evidence that VIE tags cause any negative effects that would be expected to inhibit survival upon wild release, but tag loss had reached 12% in both tagged treatments after 7 weeks and showed no sign of abating. Our study suggests that VIEs effectiveness in discerning cultured lobsters long after wild release may be limited when used in smaller juveniles. © 2015 John Wiley & Sons Ltd.
Agency: GTR | Branch: Innovate UK | Program: | Phase: Feasibility Study | Award Amount: 211.30K | Year: 2014
Support from the Agri-tech catalyst has been secured for a 15 month project addressing fundamental food security challenges by examining novel angles to expand the aquaculture industry; to include a species not currently exploited, the European Lobster. This species commands the highest value (by volume) of any species landed in the UK and supply does not meet demand. Sea based culture, in containers (SBCC) exhibit potential for a low carbon form of rearing with no feed costs. The project will design and develop a SBCC system specifically designed for nursery and on-growing, that can be used to rear the product to a marketable size. The project will set up a marine licence, essential for establishing a pilot scale site, so that future work can develop the essential tools and techniques required in order to pioneer a new industry. The consortium will be led by the National Lobster Hatchery and consists of three SMEs and micro SMEs, two HEIs and a Government Agency.
Agency: GTR | Branch: Innovate UK | Program: | Phase: Collaborative Research & Development | Award Amount: 1.02M | Year: 2016
Support from the Agri-tech catalyst has been secured for a 36 month project, addressing fundamental food security challenges by examining novel angles to expand aquaculture; to include a species not currently exploited, the European Lobster. This species commands the highest value (by volume) of any species landed in the UK and exhibits a significant supply deficit. Sea based culture, in containers (SBCC) exhibits the potential for a low carbon form of rearing with no feed costs. The project will use containers specifically designed for the species, developed in an early stage project, to assess performance and develop holistic application of SBCC systems. The project will run a pilot scale lobster farm to gather practical, operational, environmental, biological, engineering, economic and social data that can be used to develop an essential tool to encourage and inform future investment. The consortium will be led by the National Lobster Hatchery and consists of two SMEs, two HEIs and a Government Agency.
Agency: GTR | Branch: Innovate UK | Program: | Phase: Innovation Voucher | Award Amount: 5.00K | Year: 2013
Land based production of marketable sized lobsters is not currently feasible in the UK, thus cage culture systems in estuarine and coastal conditions could provide a sustainable alternative to providing a valuable human protein source at minimal unit cost of production. This project aims use marine engeneering expertise to desin and develop a rearing systems specifically for lobsters which enables more streamlined deployment, assessment and maintenance.