Delivering improved fertility and sperm storage solutions for salmon aquaculture

AIMS OBJECTIVES AND ACTIVITIES: Salmon farming has achieved major growth and success over a short period, but global demands mean that aquaculture will need to play a vital role in supplying animal protein to a fast-growing human population (World Bank 2014). Two overlapping bottlenecks currently limit progress in salmon aquaculture: (1) the ability to realise consistently high levels of fertility through artificial in vitro fertilisation, and (2) the ability to reliably store sperm both within and between spawning seasons. Fortunately, a very large body of research knowledge exists on reproduction, fertilisation, and sperm storage and cryopreservation in salmonids, which we will translate through this innovation project into practices that meet the specific needs of salmon aquaculture for improved breeding and stock enhancement.

PROJECT PARTNERS AND AQUACULTURE CHALLENGES: Alastair Hamilton and his team at Landcatch Natural Selection Ltd will work with Matt Gage (UEA), combining practical expertise from industry with scientific knowledge and skills. Breeding and stock enhancements within salmon aquaculture have so far focused (successfully) on improvements in growth, feed conversion and disease resistance. However, it is essential at this early stage in salmon farming that we do not neglect challenges from fundamental reproductive biology, which must be carefully managed through the domestication process as new strains and processes are developed. Broodstock fertility already presents significant constraints on progress in salmon aquaculture, and this should be guarded against into the future. Fertility that is often below 50% currently limits productivity into the farm stage by reducing the number of eyed eggs and fry that can be generated for the grow-on stages to market. Low fertility also significantly constrains the ability to replicate cross-strain breeding selection and stock improvements.

In addition to fertility limitations, ineffective sperm storage solutions place major breeding barriers on stock enhancement. Short-term (days to weeks) sperm storage using extenders and chilling can be implemented on the farm that researchers have used to achieve fertility up to 33 days from strip. Longer-term cryo-storage has a detailed history of investigation in fish, especially salmon, and methods are now developed that should allow reliable storage over years. Translating established knowledge and technology into farm salmon sperm storage solutions will transform aquaculture's ability to select for farm-friendly traits and enhance stocks, especially with the availability of modern genomic selection.

DELIVERABLES AND OUTPUTS: The project will deliver better fertility and sperm storage solutions, immediately benefiting farm productivity, and transforming the ability to select for and diversify optimal aquaculture traits. The outputs will be technical reports and demonstrations of work practice that detail how improvements in fertility and sperm storage can be applied on the farm, disseminated direct to Landcatch through Dr Alastair Hamilton and his team. The reports will be evolved and optimised under discussion between the team members so that the farm practicality perspective is prioritised, allowing successful implementation of change among farm processes and workers directly as a result of successful Knowledge Exchange. Ultimately, reports will be published in peer-reviewed international impact journals, and disseminated at the European Aquaculture Society annual meeting in Croatia '17. Peer-reviewed outputs will be produced in rapid-publication journals with relevance to the aquaculture industry; we anticipate four papers: two describing improvements in sperm recovery, handling, analysis and fertilization, and two on short-term and long-term sperm storage solutions.

PROJECT DURATION: 18 months, to encompass two spawning seasons and to allow 6-12 month testing of cryopreservation.

TOTAL COST: £185k (80% FEC)

This Innovation project will allow breeding improvements that help salmon farming improve its short- and long-term productivity. These improvements will directly benefit Landcatch ltd and the wider aquaculture industry, and its supply chain to market. In turn, improved production will benefit a global consumer market that now enjoys much more widely what was previously a very rare luxury food item.

Salmon farming is clearly an important, multi-billion dollar activity, with substantial export value to those countries where it operates, and potential to expand geographically even further using land-based systems. However, salmon farming is held back by two overlapping challenges within fish breeding: (1) broodstock fertility, and (2) reliable sperm storage.

Artificial fertilization using gametes stripped from ripe adults is employed to create eyed eggs for grow-on to market, and for stock selection and enhancement. However, fertilization success rates on the farm are frequently below 50%, and sometimes zero, creating major constraints on production and stock enhancement. Researchers have been able to achieve ~90%+ IVF success rates, so this Innovation project will translate that knowledge into farm breeding to realize direct benefits to the aquaculture industry.

In addition to low fertility, sperm storage, both within and between seasons and generations, is undeveloped in salmon aquaculture, and would transform the capacity for much improved stock enhancement. Reliable cryopreservation of banked sperm would allow major advances in stock selection and movement, directly informed by farm performance, and taking advantage of improvements in modern genomic selection. Again, researchers have been able to reliably store salmonid sperm, so this Innovation project seeks to translate that rich technology, and up-scale sperm storage for the salmon farm environment. Reliable short- and long-term sperm storage will allow considerable benefits to production and efficiency in the salmon aquaculture industry.

To translate the considerable knowledge and technology base from scientific research into breeding improvements for salmon aquaculture, the project will work closely with Landcatch and Hendrix breeding facilities, to integrate and optimize technologies and knowledge for production and stock enhancement improvements through a number of potential farm practices (see Case For Support). We have assembled a team that combine complementary skills and knowledge from the science of salmonid reproduction to the needs and practices of a major industrial player at Landcatch. The proposed Senior Research Assistant for the project has worked in both universities and at Landcatch, and is experienced in delivering impact from research to the industry, previously through feed conversion and fillet quality improvements. This new project will drive impact by improving the breeding practices of salmon farming.

Being an Innovation project, all the activity across the 18 months is directed at Impact, which we detail through the Case For Support. By transferring knowledge and skills through a close working relationship at Landcatch ltd, managed by PI and PP Gage and Hamilton respectively, the project will integrate, test, demonstrate, and document improvements in breeding and sperm storage so that standard industry practices are informed and improved. The project will document all improvements for breeding and sperm storage in farm-staff accessible formal reports, taking advantage of modern audio-visual opportunities weber relevant, such as video-clip demonstrations of practical improvements or where verbal explanations can best achieve knowledge exchange. in On project completion, and respecting any industrial confidentiality requirements, peer reviewed publications in aquaculture-relevant international impact journals will allow the improved technology to spread beyond the UK, potentially to emerging aquaculture using new finish species.