Obligate and opportunistic parasites play a critical role in determining the productivity, sustainability and economic viability of global finfish aquaculture enterprises. Without stringent and appropriate control measures, the impacts of these pathogens can often be significant.
Selection for disease resistance has been used in breeding farm animals and can be a viable option to deal with white spot syndrome and acute hepatopancreatic necrosis disease in commercial shrimp culture. In trials, heritability for AHPND resistance was low, while that for WSS was moderate.
Strategies to control Vibrio bacteria at aquaculture farms must revolve around limiting inputs, including those from postlarvae suppliers, those that come in with the water, those that remain in the soil between crops and those in the feed and accumulated organic matter.
Control of Vibrio bacteria should focus on minimizing overall bacterial loads and the potential for horizontal transmission. The challenge for hatchery managers is identifying gaps in biosecurity and plugging them without creating niches for other potential pathogens.
Environmental lighting, which synchronizes all stages of aquatic life, is an important consideration as more aquatic animals are produced indoors in highly controlled environments. Artificial lighting should deliver uniform light across the water’s surface in rearing tanks and mimic not only photoperiod, but also light color and intensity.
Interest in the aquaculture of stalked barnacles has risen in recent years as a response to increasing market demand and concern over the conservation of natural stocks. Is there enough knowledge, however, to establish the culture of stalked barnacles?
Anecdotal information has suggested that pond-reared hybrid striped bass are more vulnerable to transportation-related stressors than cage-reared fish. Study results suggested that accumulation of carbon dioxide and decreasing pH levels may contribute to this phenomenon. Agitation during simulated transport mitigated the carbon dioxide accumulation and stabilized pH, but shifted the total ammonia nitrogen equilibrium in favor of un-ionized ammonia nitrogen.Ultimately, the agitators did not substantially attenuate the stress responses observed in the fish.
The use of larger and deeper tanks can reduce building, labor and other aquaculture production costs. However, the ability to grade and transfer large numbers of fish is more challenging when using large tanks. In a comparison of the effectiveness of a purse seine and a hinged clamshell to crowd fish in large tanks, the latter was easier to control and less stressful to salmonids. With a slotted bar rack in a side panel of the clamshell crowder, fish were simultaneously graded in size.
While sea cucumbers are one of the most prized seafoods in China and Asia, their production suffers from suboptimal juvenile production. The use of proper feeds and overall management in the nursery can improve yield and survival.
To develop an alternative mechanism for genetic copyright of improved shrimp lines, the authors used a bioinformatics approach to identify germ line genes that could be potentially targeted to ablate the germ line.
This article reports on a breeding program focused only on the improvement of growth rates at associate farms in Ecuador. By applying a localized breeding strategy, the program has yielded an average 7.8 percent annual phenotypic gain for commercial growth rates, while survival has remained fairly constant.
To help minimize economic losses caused by acute hepatopancreatic necrosis disease, timely detection of its pathogenic Vibrio etiological agent plays a critical part in disease management. A portable device with accompanying polymerase chain reaction assays can quickly identify the AHPND markers in shrimp, water, live feed or other sources.
The authors performed a study to determine the tolerance of shrimp postlarvae to the crowding effects of high-density stocking in terms of production performance. Postlarvae were stocked in heavily aerated microcosm tanks with biofloc at 1,500; 3,000; 6,000 or 9,000 shrimp/m3. High survival was observed at all densities. Final biomass values increased with higher stocking densities, but there was no significant difference between the 6,000 and 9,000 shrimp/m3 treatments or the 1,500 and 3,000 shrimp/m3 treatments.
The benefits realized by recirculating aquaculture systems – including enhanced fish growth, product quality and survival, as well as reduced treatment costs – have made the RAS approach an important production trend.
Real-time, quantitative polymerase chain reaction (qPCR) analysis has become an attractive alternative for quantification of the acute hepatopancreatic necrosis disease (AHPND) pathogen in infected shrimp. The authors developed a qPCR assay to quantify a virulence plasmid harbored by the bacterium that causes AHPND.
The bacterium Flavobacterium columnare and parasite Ichthyophthirius multifiliis (Ich) are common pathogens that can cause heavy economic losses for fish culture. The authors conducted a study to evaluate the susceptibility of hybrid tilapia to F. columnare, including fish mortality and bacterial numbers in fish after parasitism by Ich.