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Murray H.M.,Institute for Marine Biosciences | Murray H.M.,Scotian Halibut Ltd | Lall S.P.,Institute for Marine Biosciences | Rajaselvam R.,Genome Atlantic | And 8 more authors.
Marine Biotechnology

An experimental microdiet prepared using an internal gelation method was used to partially replace the traditional live feed (Artemia) for larval Atlantic halibut, Hippoglossus hippoglossus L. Three trials were conducted with microdiet introduced at 20, 32, and 43 days post first feeding and larvae were sampled at approximately 2, 13, 23, and 33 days after microdiet introduction in each trial. The success of feeding was assessed by morphometrics and histological analysis of gut contents. Microdiet particles were readily consumed after a period of adaptation and provided an adequate source of nutrients with no significant increase in mortality in the microdiet-fed group compared to the control group. However, growth was limited and there was an increased incidence of malpigmentation of the eye and skin. Subtle changes in underlying digestive and developmental physiology were revealed by microarray analysis of RNA from control and experimental fish given microdiet from day 20 post first feeding. Fifty-eight genes were differentially expressed over the four sampling times in the course of the trial and the 28 genes with annotated functions fell into five major categories: metabolism and biosynthesis, cell division and proliferation, protein trafficking, cell structure, and stress. Interestingly, several of these genes were involved in pigmentation and eye development, in agreement with the phenotypic abnormalities seen in the larvae. © 2009 Her Majesty the Queen in Right of Canada, as represented by the National Research Council of Canada. Source

Corey P.,Scotian Halibut Ltd | Kim J.K.,University of Connecticut | Kim J.K.,Dalhousie University | Duston J.,Dalhousie University | Garbary D.J.,St. Francis Xavier University

Palmaria palmata was integrated with Atlantic halibut Hippoglossus hippoglossus on a commercial farm for one year starting in November, with a temperature range of 0.4 to 19.1°C. The seaweed was grown in nine plastic mesh cages (each 1.25 m3 volume) suspended in a concrete sump tank (46 m3) in each of three recirculating systems. Two tanks received effluent water from tanks stocked with halibut, and the third received ambient seawater serving as a control. Thalli were tumbled by continuous aeration, and held under a constant photoperiod of 16: 8 (L: D). Palmaria stocking density was 2.95 kg m-3 initially, increasing to 9.85 kg m-3 after a year. Specific growth rate was highest from April to June (8.0 to 9.0°C), 1.1% d-1 in the halibut effluent and 0.8% d-1 in the control, but declined to zero or less than zero above 14°C. Total tissue nitrogen of Palmaria in effluent water was 4.2 to 4.4% DW from January to October, whereas tissue N in the control system declined to 3.0-3.6% DW from April to October. Tissue carbon was independent of seawater source at 39.9% DW. Estimated tank space required by Palmaria for 50% removal of the nitrogen excreted by 100 t of halibut during winter is about 29,000 to 38,000 m2, ten times the area required for halibut culture. Fifty percent removal of carbon from the same system requires 7,200 to 9,800 m2 cultivation area. Integration of P. palmata with Atlantic halibut is feasible below 10°C, but is impractical during summer months due to disintegration of thalli associated with reproductive maturation. © 2014 The Korean Society of Phycology. Source

Kim J.K.,Dalhousie University | Duston J.,Dalhousie University | Corey P.,Dalhousie University | Corey P.,Scotian Halibut Ltd | Garbary D.J.,St. Francis Xavier University

Optimal stocking density of the marine red algae Chondrus crispus and Palmaria palmata was determined to maximize productivity and nitrogen removal in a land-based Atlantic halibut farm. Both species were cultured at 0.2, 2, 4, 6 and 10kgm-2 for four weeks at 140±10μmolphotonsm-2s-1 of photosynthetically active radiation (PAR) and 16:8 L:D photoperiod. For each species, two rearing temperatures were compared at different times of the year: 6 (Dec.) and 13°C (June) for C. crispus, and 6 (Mar.) and 16°C (July) for P. palmata. Growth rates of both species were inversely dependent on stocking density at all temperatures; however, the productivity (gfresh weightd-1) in Chondrus was significantly higher at 2kgm-2 than 0.2kgm-2 at both temperatures. By contrast, productivity of Palmaria was independent of stocking densities of 0.2 through 6.0kgm-2 at both temperatures. The net N removal in Chondrus was the highest at 2.0kgm-2 at both temperature conditions. Palmaria also showed the highest N removal at 2.0kgm-2 at 6°C but at 4.0kgm-2 at 16°C. Overall, C. crispus was the better performer year-round than P. palmata in terms of productivity and nutrient removal capacity. © 2013 Elsevier B.V. Source

Caines S.,Dalhousie University | Manriquez-Hernandez J.A.,Dalhousie University | Duston J.,Dalhousie University | Corey P.,Scotian Halibut Ltd | Garbary D.J.,St. Francis Xavier University
Journal of Applied Phycology

The high cost of aeration needed to tumble culture macroalgae is a limiting factor for integration with land-based finfish culture. Toward reducing this electricity cost, we compared intermittent aeration (16 h on:8 h off) with continuous aeration (24 h on) on the productivity of two strains of Chondrus crispus (Basin Head and Charlesville) and Palmaria palmata from Atlantic Canada between May and June 2011. Algal fronds were cultured under a 16:8-h light/dark photoperiod in 50-L tanks supplied with finfish effluent (49 μmol L−1 of ammonium and 11μmol L−1 of phosphate) at a mean water flow rate of 0.4 L min−1. Nitrogen (N) influx was 1.8 gN m−2 day−1, and phosphorus (P) influx was 0.9 gP m−2 day−1, with uptake rates ranging from 0.02 to 2.4 gN m−2 day−1 and −0.2 to 0.4 gP m−2day−1. On average, the macroalgae culture system (algae and biofilms) removed 1.0gNm−2day−1 (51.9%). The growth of macroalgae (pooled across treatment and strain) ranged from 0.5 to 1.6%day−1, which accounted for a yield of 2.2 to 5.4 g DW m−2 day−1. Switching off aeration at night improved the growth rate of Basin Head Chondrus by 146% and had no effect on growth rate or nitrogen and carbon removal by P. palmata and Charlesville Chondrus. Growth and yield of Basin Head Chondrus under intermittent aeration were over two times greater than both Charlesville Chondrus treatments. © 2014, Springer Science+Business Media Dordrecht. Source

Ding F.,Chinese Academy of Fishery Sciences | Milley J.E.,National Research Council Canada | Rommens M.,Scotian Halibut Ltd | Li J.,CAS Qingdao Institute of Oceanology | And 2 more authors.

Hormone implantation is widely applied in halibut (Hippoglossus hippoglossus L.) aquaculture to extend the sperm production season of broodstock males. The ability to combine this technique with cryopreservation would increase sperm availability, thereby improving reproduction success and facilitating gene management. In this paper, the cryopreservation ability of sperm from hormone-treated males was examined at three times post-implantation and compared with that of sperm from males that were not hormone-treated. All sperm samples were cryopreserved using the same method. The effectiveness of these techniques was assessed by examining the fertilization rate and motility of thawed sperm. The spermotocrit and concentration of fresh sperm samples were measured to reveal the effect of hormone implantation on sperm characteristics. The reported results indicate that hormone implantation did not affect cryopreservation efficiency. The fertilization rate resulting from thawed sperm of hormone-treated males showed no significant difference from that of untreated males or from fresh sperm. A significant positive relationship was demonstrated between the spermatocrit and concentration of sperm; and a significant decrease of spermatocrit was found in sperm collected from hormone-treated males 14. days post-implantation. No significant linear relationship between spermotocrit and fertilization rate of thawed sperm was shown. © 2012. Source

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