Guernsey Sea Farms

What Guernsey Sea Farms does

Guernsey Sea Farms is a family-run oyster hatchery and nursery based in Guernsey, Channel Islands, with origins in the early 1970s and a dedicated hatchery facility built in 1983 by founders Mark and Penny Dravers. The business produces Pacific oyster (Crassostrea gigas) seed in both diploid and triploid forms and operates a secondary ecotoxicology testing service for environmental laboratories. It is one of only two mollusc hatcheries in the United Kingdom and the sole UK supplier of disease-free triploid oyster seed, a position underpinned by Guernsey's geographic isolation and the absence of native oyster or mussel populations, which provide biosecurity against OsHV1µvar and Vibrio aestuarianus.\n\nThe technical platform centres on aquaculture infrastructure sited in a unique granite quarry with sluice-gate water access. Core systems include a custom Floating Upweller System (FLUPSY) with paddle wheel moving 30 tons of water per minute on under 0.5kW, micro-algae production at 300m3/day, 80-90% heat recovery, and an in-house flow cytometer for triploid ploidy verification. The team grades 20 million seed per person every two weeks, indicating a high-throughput operation relative to its small headcount of approximately five to six personnel.\n\nRevenue is generated through two channels: commercial oyster seed sales to aquaculture farmers across a wide international market (Europe, USA, Hong Kong), and contract ecotoxicology testing for environmental laboratories. The business is undergoing a generational succession, with Josie Chandler and Tom Hollingsworth taking over from the Dravers founders effective January 2026, preceded by the October 2024 appointment of James Dickinson as Director and General Manager.

Name

Guernsey Sea Farms

Legal name

Guernsey Sea Farms Limited

Website

https://guernseyseafarms.com

Company type

Private

Founded year

1970

Operating status

Operating

Short description

Guernsey Sea Farms is a family-run Guernsey-based oyster hatchery producing diploid and triploid Crassostrea gigas seed, operating as the only UK supplier of disease-free triploid seed while also offering ecotoxicology testing to environmental laboratories across an international market.

Ownership category

akta.pro rank

Product category

Mollusc Aquaculture / Oyster Hatchery

NAICS

Shellfish Farming (112512), Aquaculture (11251)

SIC

Agricultural Prod-Livestock & Animal Specialties (200), Agricultural Services (700)

akta.pro primary industry

Marine Shellfish Farming (e.g., oysters, mussels, clams) (AFAEAAAB)

akta.pro secondary industry

Shellfish Wholesale (Crustaceans & Mollusks) (AFAIADAF)

Keywords

• Oyster hatchery operations
• Oyster seed production
• Ecotoxicology testing services
• Aquaculture nursery services
• Bivalve seed supply

Headquarters

HQ city

St. Peter Port

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Operations, Supply Chain, Personnel, Infrastructure, Others

Revenue model

1. Oyster Seed Sales: Supplying disease-free oyster seed (both diploid and triploid) to farms around the world. Seed is delivered internationally within 48 hours. Main products include Crassostrea gigas seed in various sizes (G4, G7, G10, G13).
2. Ecotoxicology Testing Services: Supplying marine organisms for ecotoxicology testing to environmental laboratories throughout Europe, USA, and Hong Kong for over 25 years. Also performs inter-laboratory tests, range finder tests, and oyster embryo bioassay tests. Marine organisms available include Crassostrea gigas, copepods (Acartia tonsa, Tisbe battagliai), and marine micro-algae.

Go-to-market motion2 records

Distribution channels1 record

Marketing channels4 records

Core offering

Guernsey Sea Farms is a family-run oyster hatchery and nursery based in Guernsey, Channel Islands, producing diploid and triploid Crassostrea gigas (Pacific oyster) seed for commercial oyster farmers. In addition to seed supply, the company provides ecotoxicology testing services to environmental laboratories.

Product overview

Guernsey Sea Farms is an oyster hatchery and nursery operation offering two main product lines: oyster seed production (both diploid and triploid Crassostrea gigas) and Ecotox services for environmental laboratories. The oyster seed products are produced through their proprietary hatchery process and delivered internationally within 48 hours. The company is one of only two mollusc hatcheries in the UK and the only UK supplier of disease-free triploid oyster seed. Their Ecotox division supplies marine organisms for ecotoxicology testing globally.

Differentiator

Problem solved

Functional benefit

Products and services

• Diploid Crassostrea gigas Oyster Seed Diploid (fertile) Pacific oyster (Crassostrea gigas) seed produced at the hatchery and supplied to commercial oyster farmers for on-growing.
• Triploid Crassostrea gigas Oyster Seed Triploid (sterile) Pacific oyster (Crassostrea gigas) seed produced at the hatchery, typically used by commercial growers for faster growth and year-round marketability.
• Ecotoxicology Testing Services Ecotoxicology testing services supplied to environmental laboratories, leveraging the facility's controlled hatchery conditions to support regulatory and research testing.

Quantifiable outcome

• 80% survival rate achievable with best husbandry practices
• +5 more outcomes

Named customers4 records

Segments3 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature7 records

Scale indicators8 records

Recent moves5 records

Expansion highlights3 records

Regional players

• Scottish Sea Farms: Major UK salmon aquaculture operator jointly owned by SalMar and Lerøy. Comparable as a UK-based aquaculture operator in the same regulatory and geographic context as Guernsey Sea Farms' UK customer base.

Broad incumbents

• Pacific Seafood Group: Family-owned US seafood conglomerate with vertically integrated harvesting, processing and distribution. Comparable as a major privately held seafood operator serving similar foodservice and retail channels.
• Mowi ASA: World's largest aquaculture company, primarily Atlantic salmon but with broad seafood portfolio and global operations. Comparable as a large-scale aquaculture incumbent but with focus on finfish rather than shellfish.
• Huon Aquaculture: One of Australia's largest aquaculture producers (salmon and trout), now owned by JBS. Comparable as a vertically integrated aquaculture operator serving similar end markets in the Southern Hemisphere.
• SalMar: One of the world's largest Atlantic salmon producers with operations in Norway and internationally. Comparable as a major aquaculture incumbent with strong focus on hatchery and farming technology innovation.
• Cermaq: Global salmon aquaculture company owned by Mitsubishi Corporation, operating in Norway, Chile and Canada. Comparable as a large aquaculture incumbent in species diversification and international market reach, though finfish-focused.

Others

• Skretting: World's largest producer of aquaculture feed, supplying salmon, shrimp and other species including shellfish. Adjacent ecosystem participant — Guernsey Sea Farms relies on micro-algae production but does not buy feed; relevant for industry context and supply chain comparability.

Direct peers

• Coast Seafood: Norwegian seafood company specializing in oysters and other shellfish, supplying European markets. Directly comparable as a European shellfish supplier operating in adjacent geography with overlapping customer types.
• Loirston Shellfish: The other mollusc hatchery operating in the UK, producing Pacific oyster seed for Scottish and UK growers. Directly comparable niche hatchery operator with similar species focus and customer base.
• Taylor Shellfish Farms: One of the largest Pacific shellfish producers in North America with integrated hatchery, nursery and grow-out operations. Comparable as a vertically integrated oyster seed and grow-out business with proprietary hatchery technology.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• Facebookfacebook.com/guernseyseafarms

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Guernsey Sea Farms