United Kingdom
United Kingdom

Time filter

Source Type

Bravo S.,Austral University of Chile | Treasurer J.,Ardtoe Marine Laboratory | Sepulveda M.,Salmones Ventisqueros | Lagos C.,Austral University of Chile
Aquaculture | Year: 2010

Hydrogen peroxide (H2O2) was the only effective alternative treatment to emamectin benzoate (EMB, SLICE, Schering Plough) for the sea louse Caligus rogercresseyi in Chile during the period from February to September 2007. This introduction was due to the loss of sensitivity of lice to EMB after 7 years of exclusive use. A detailed field appraisal of treatments was carried out on salmon farms at two sites near Puerto Montt (Lat 42oS) in August 2007 to evaluate the efficacy of hydrogen peroxide in the control of C. rogercresseyi. A skirt was used on one farm for treatments and an enclosed tarpaulin in the other. Hydrogen peroxide was applied by bath at a concentration of 1.5 g l-1 for 20 min treatment but this did not kill C. rogercresseyi. Most of the parasites recovered from the treatment and were available to infest new hosts. Treatments were carried out in tanks under laboratory conditions to test the findings obtained in the field and these gave similar results. Caligus recovered completely after 30 min post treatment. © 2010 Elsevier B.V. All rights reserved.


Treasurer J.W.,Ardtoe Marine Laboratory | Bravo S.,Austral University of Chile
Aquaculture | Year: 2011

The location of attached and mobile stages of Caligus rogercresseyi and C. elongatus on Atlantic salmon Salmo salar hosts was compared with that of the distribution patterns of Lepeophtheirus salmonis. The distribution of C. rogercresseyi was also compared in experimental and natural infections, and there were no significant differences for either attached or mobile stages between infection routes. Most C. rogercresseyi chalimi were located on the abdomen and post anal areas. Although the distribution of mobile stages was more homogenous there was a significantly higher percentage on the post anal area, 35% of all mobiles, compared with the salmon surface in the post anal region of only 3%. Significantly more attached stages, from 70 to 75%, of both Caligus species were located on the fins compared with mobiles. The mobile stages of both Caligus species had a predilection for the abdominal body. A higher percentage of attached stages of C. elongatus was located on the ventral fins and tail compared with C. rogercresseyi and, in contrast,significantly more were present on the body in C. rogercresseyi. However, there was no difference in the distribution of mobile stages of the two Caligus species with a significantly higher percentage located on the abdomen. In contrast, mobile L. salmonis were predominantly located on the back and head. Significantly more attached stages of L. salmonis were present on the dorsal fins and adjoining basal epidermis, 30% comparedwith <. 2% in the Caligus species. These results suggest that C. rogercresseyi and C. elongatus show similar preferences for the host ventral body and fin locations and there is no direct competition for host substrate between C. elongatus and L. salmonis. © 2011 Elsevier B.V.


Di Iorio L.,ENSTA Bretagne | Gervaise C.,CNRS GIPSA Laboratory | Jaud V.,ENSTA Bretagne | Robson A.A.,Ardtoe Marine Laboratory | Chauvaud L.,Institut Universitaire de France
Journal of Experimental Marine Biology and Ecology | Year: 2012

Bivalve mollusks are of major ecological and economical importance in coastal ecosystems. They are natural archives of environmental information extractable from its shell. The formation and size of growth increments delimited by striae are affected by environmental stressors. The mechanisms linking shell growth and striae deposition in relation to environmental variations are poorly understood but are likely associated with the animal's valve-movement behavior. Here, we present a first attempt to record scallop valve movement using passive acoustics. This method has the advantage of being totally non-intrusive and deployable continuously, over the long term (months) and on a large number of individuals. By comparing simultaneous acoustic recordings with data from animal-attached movement sensors, we show that bivalve (Pecten maximus) adduction movements (here 'coughs') produce a specific sound. To evaluate the use of passive acoustic monitoring of these sounds in natural environments, we estimated if scallop coughing sounds are detectable in typical scallop habitats with different ambient noise levels. We found that scallop coughing sounds can be detected from a few to several tens of meters in different ambient noise environments. Furthermore, their acoustic characteristics are distinctive from those of other known benthic organisms. These results indicate that scallop valve movements can be monitored using passive acoustics in situ. We emphasize that acoustic recording is likely to become a powerful, non-intrusive method for the long-term monitoring of the behavior of a pectinid species and its responses to environmental changes affecting growth. © 2012 Elsevier B.V.


Treasurer J.,Ardtoe Marine Laboratory | Feledi T.,Research Institute for Fisheries
Journal of the World Aquaculture Society | Year: 2014

Several indices were examined to assess the physical condition of wrasse stocked on Atlantic salmon, Salmo salar, farms as cleaner fish, and included examination of eye condition, snout erosion, skin hemorrhaging, and erosion and splitting of dorsal, pectoral, anal and caudal fins. Baseline values were determined for five wrasse species: goldsinny, Ctenolabrus rupestris; rock cook, Centrolabrus exoletus; corkwing, Crenilabrus melops; cuckoo, Labrus mixtus; and ballan, Labrus bergylta, held in a farm environment for 3 mo prior to transfer to salmon farms. The caudal fin was most affected by injury. The fin erosion index (FEI) was low in all species and below 0.6. The fin splitting index (FSI) was the most prominent index and was significantly higher in the caudal fin (FSI>2) compared with other fins (FSI<0.5), and also significantly higher in corkwing and rock cook compared with the other wrasse species. The FEI and FSI were also calculated for a group of ballan wrasse before stocking on a seawater farm, during the first winter and upon harvesting. There were no significant differences in the scores of fin erosion and fin splitting in any of the samples, although the indices were marginally poorer in winter. © by the World Aquaculture Society 2014.


Robson A.A.,University of Western Brittany | Robson A.A.,Ardtoe Marine Laboratory
Nutrition and Health | Year: 2011

It is crucial that emergent technologies create foods that help prevent the causal mechanisms of the diet induced disease epidemic. Food nanotechnology could create modern convenience foods that mimic and improve on the nutritional value of the most nutritious cooked wild foods for humans. Structuring a solid processed food similar to a celery stalk using selfassembled, water-filled, edible nanocells or nanotubes would substantially lower its energy density (<1.6 kcal g"1).Food technologists could harness the natural turgor force to produce a firm chocolate bar, biscuit or breakfast cereal with a good bite, without altering the appearance or taste of the product. Water carriesflavour with few calories, and taste sensation per mouthful could be improved by processing food on the nanoscale to increase the surface area that is in contact with taste and smell receptors. The bioavaiiable nutrient content (including cofactors) of processed foodscould be increased by existing bioactive nanoencapsulation. This would allow people to continue to consume modern convenience food on a mass scale, while simultaneously and significantly increasing nutrient intake and reducing energy intake per day. Thus, helping to reduce mental ill health, obesity and other postprandial insults. © 2011 A B Academic Publishers.


Treasurer J.,Ardtoe Marine Laboratory | Ford L.,Ardtoe Marine Laboratory
Journal of Applied Ichthyology | Year: 2010

Potential predictors of egg quality were assessed in whiting Merlangius merlangus L. permitted to spawn in a tank from which eggs were collected. These included fertilisation rate, the proportion of viable buoyant eggs, egg diameter, and egg wet and dry weights; all were influenced by temporal effects and were negatively correlated with days from start of spawning. The spawning period was protracted, from February to June. Mean daily egg production per female was 2.74 ± 2.43 g and 2338 ± 2075 eggs, equivalent to 14.6 ± 13.1 g kg-1 day-1 female-1. Egg diameter was 1.21 ± 0.04 mm, egg wet weight 1.20 ± 0.21 mg, dry weight 0.10 ± 0.02 mg, and mean fertilisation rate and hatching rates were 76.8 and 73.3%, respectively. The incubation period ranged from 72 to 80 degree days and was dependent on temperature (x) and described by the equation y = 25.92 e-0.1219x. Realised fecundity was also assessed to determine if this gave a more accurate measure of reproductive potential, and this was compared with potential fecundity estimated from predictive regressions on fish length from fisheries data. Realised egg production of 20 females of 185 g mean weight and 256 mm fork length was 4 444 360 (95% CL 4 093 961-4 743 018), similar to predicted seasonal egg production based on gravimetric fecundity measurements of wild caught fish. © 2010 Blackwell Verlag, Berlin.


The stress and trauma associated with handling and movement of fish may have welfare implications and may also increase susceptibility to disease post-transfer. Juvenile salmonids have been transported live from hatchery to production grow out units for some time but little information is available on the live transport of marine finfish species such as Atlantic cod, Gadus morhua L. The present study examines the accumulation of un-ionised ammonia (UIA-N) in live transport of juvenile cod and examines the effectiveness of aeration, an ammonia absorbing agent and duration of fast period in controlling the level of UIA-N. UIA-N increased significantly with higher stocking densities in simulated transports of 24h duration, from 0.08μgl-1 at 10kgm-3 to 0.43μgl-1 at 30kgm-3, and also with duration of the simulated transports, rising from 1.14μgl-1 after 3h to 6.01μgl-1 at 24h in a second trial. Average UIA-N was significantly higher when diffuse aeration with air as well as oxygenation was used, 9.03μgl-1 compared with 1.54μgl-1 with oxygenation only. Air diffusion had the effect of maintaining a higher pH which consequently increased the potential for ammonia toxicity. Mean ammonia level was significantly less at 3.17μgl-1 in a simulated 24h transport when an ammonia absorbing product was used compared with 6.01μgl-1 l UIA-N in control tanks. This additive would be beneficial during transports of marine finfish for the regulation of ammonia. The effects of varying fast periods and related duration of gut evacuation in juvenile cod on water chemistry including ammonia levels were also assessed. From this an optimum fast period of 36h for live transport of cod at 12°C is recommended. Stocking densities of up to 30kgm-3 did not give rise to toxic levels of ammonia. Aeration in addition to oxygenation, while increasing pH, leads to elevated ammonia, but ammonia accumulation can be reduced by using an absorbing agent. © 2010 Elsevier B.V.


Treasurer J.,Ardtoe Marine Laboratory | Atack T.,Ardtoe Marine Laboratory | Rolton A.,Ardtoe Marine Laboratory | Walton J.,Biomar Ltd | Bickerdike R.,Biomar Ltd
Aquaculture | Year: 2011

A large proportion of cod juveniles fail following transfer to sea cages from the hatchery. Failed cod take and then eject feed and are thin and emaciated fish of low weight compared with "normal" siblings. Failed fish comprised 70% of total mortalities and 10% of fish stocked in the first eight months of production on a cod farm in Scotland. Failed cod comprised from 0 to 8% of fish reared in twelve hatchery tanks over 3months. These failed cod were graded from larger fish in five consecutive grades at four to six weekly intervals and, after being reared separately, over 90% of these fish were "recovered". No significant differences were found in food acceptance of six alternative diets and a standard marine commercial diet by failed cod. Smaller pellets or feed moistened in seawater were offered but this did not significantly increase the rate of feed acceptance. The effects of stocking density on the development of failed cod were assessed by comparing performance at densities of 0.2, 2 and 20kgm -3. Aggressive interaction was lowest at an intermediate stocking density of 2kgm -3 and highest at a density of 20kgm -3. Fin nipping was concentrated on the first dorsal fin and was not significantly different between stocking densities, but the other dorsal fins, pectoral fins and tail were also attacked more frequently at the highest stocking density. It is concluded that failed cod can be recovered by grading from the main population and feeding these cod separately. Stocking densities in sea cages should initially be similar to hatchery levels and this may be achieved by holding the cod in small enclosures within the main net. © 2011 Elsevier B.V.


Salmonids have been transported from hatchery to ongrowing units for many years, but little information is available on optimal conditions for the transport of marine finfish species. This study examined the changes in pH that occur under various simulated transport conditions of stocking density and fish size, and thereby recommends protocols for live marine fish transportation. The pH of the transport water declined rapidly due to the respiration of carbon dioxide. Various buffers (sodium bicarbonate, TRIS, Magnaspheres) were compared and maintained pH close to normal seawater levels. The decline in pH was greater with small (18g) rather than larger (32g) fish, at identical loading biomass in tanks, indicating that fish size should be considered when planning transport. Although unionised ammonia level increased with increasing stocking density (10 to 30kgm -3) the pH did not decline significantly. The use of air aeration as well as oxygenation reduced CO 2 levels indicating that aeration stripped the CO 2 from the water. Non invasive measurements of free cortisol release into the tank water by juvenile cod indicated primary stress response to handling events. This study demonstrates that cod juveniles will be exposed to fluctuating pH in transport tanks, and buffering of the pH and stripping of CO 2 by aeration to reduce fluctuations is recommended. © 2011 Elsevier B.V..


Treasurer J.W.,Ardtoe Marine Laboratory
Journal of Fish Diseases | Year: 2012

There have been several reported studies of wrasse health but none of these has shown transmission of wrasse diseases when stocked with farmed Atlantic salmon. Most of the studies have focussed on bacterial and parasite issues, including treatment of bacterial diseases with antibiotics and vaccination of wrasse. Classical and atypical furunculosis have been reported in wrasse following stress, and wrasse have been susceptible to vibrio infection. Further study is required on the vaccination of wrasse for furunculosis with latent carrier status to maximize survival. There are studies on viral diseases such as infectious pancreatic necrosis, infectious salmon anaemia and pancreas disease and although these did not give any undue concern for salmon health, there is also scope for further study in this area. Resident parasite communities of wrasse are largely host-specific and do not appear to be a threat to salmon. Given that wrasse have not, to date, been a vector of disease in salmon, attention should be placed on maintaining best practice in cohabiting wrasse with salmon. Other issues that should be addressed are good welfare of wrasse in pens and identifying measures of this, the identification of losses of wrasse in pens, being alert to potential emerging diseases through health screening of mortalities and assessing the risks associated with carrying forward wrasse from one salmon production cycle to the next. Issues of exploitation by fishing on wild wrasse stocks and improved biosecurity may be addressed by the increased movement by the industry to the stocking of farmed wrasse. © 2012 Blackwell Publishing Ltd.

Loading Ardtoe Marine Laboratory collaborators
Loading Ardtoe Marine Laboratory collaborators