Cormorants are a fisheries and aquaculture problem above all else. They are efficient underwater hunters, they work in groups, and where they settle on a stocked water body the losses are commercial rather than cosmetic. They also perch communally on whatever structure is available — rails, docks, posts and moored vessels — and foul it heavily.
Below are the Flock Free products we would use for cormorants. If you would rather understand the problem first, the full guide continues underneath.
Shop Cormorant Control Products
Bird Netting 3/4″ Mesh – 50' x 50'
$755.00
Covers ponds and raceways to deny access from above.
Transparent Shock Tape – 54 ft Roll
$200.00
For the rails, docks and structures cormorants perch on.
110V Charger for Shock Tape
$164.00
Charger to run a shock tape run where power is available.
Moby – Portable Hazer
$3,249.00
Portable hazer for treating the wider area around water.
Bird Repellent Concentrate – 1 gallon
$395.00
The concentrate our hazers and misting systems run on.
Flock Free Bird Bombs (5 pcs)
$41.99
Scent-repellent pods for small enclosed spaces. Repellent sold separately.
Flock Free Bird Bomb Bundle
$31.99
One Bird Bomb plus a 4 fl oz concentrate to soak it in.
Prices shown as listed at the time of publication. See each product page for current pricing and availability. Shipping restrictions apply to certain Flock Free Bird Repellent products in CT, IN, MD, MT, NM, RI, WI and DC — see the individual product page for current availability and shipping information. Other products on this page are not affected.
Cormorant work is site-specific and often commercial. Call 732-987-5400 before ordering — or keep reading below.
Continue Reading: How to Deter Cormorants
Why Cormorants Become a Problem
- Stock losses at scale. Cormorants are skilled divers and often feed in groups, so losses at a fishery or aquaculture site mount quickly.
- Damage to surviving fish. Fish that escape an attempt can be injured, which affects both welfare and saleability.
- Heavy fouling of structures. Communal perching on rails, docks, posts and vessels leaves a great deal of mess in a small area.
- They return. A productive water body is revisited, and a roost near it becomes established.
Where Cormorants Settle
- Aquaculture ponds and raceways.
- Stocked lakes and commercial fisheries.
- Rails, docks, posts and jetties beside the water.
- Moored vessels and waterside structures used for perching and drying.
Why cormorants keep coming back
The food is the draw and the perch is the convenience. Removing one without the other tends to move the birds a short distance rather than off the site, which is why the two approaches below are usually run together.
How to Deter Cormorants
Netting over the water
Where the water can be covered, netting is the most complete answer. Bird netting over ponds and raceways denies access from above, with the smaller 25' x 25' sheet for contained water.
As with any water installation, the net needs to be supported clear of the surface and closed at the margins. Cormorants are large, strong birds, so support and tensioning matter more here than on a garden pond — talk to us about specification before ordering for a commercial site.
Shock systems on perching structures
Where covering the water is impractical, the alternative is to take away the perches. Transparent Shock Tape along rails, dock edges, posts and jetty structures gives a mild, startling pulse on landing and keeps the birds off the structures they use to rest and dry. Run it from a 110V Charger where power is available, or an HD Solar Charger at waterside locations without it.
Netting and shock systems are the two routes for this species. Which one applies depends on whether the water itself can be covered.
Repellent applied around the water
Our repellent program, applied through a portable Moby hazer running on the 1 gallon concentrate, treats the wider area around a water body. The repellent is plant-based and non-toxic, exempt under FIFRA 25(b). Application around water needs planning — ask us how it should be positioned on your site.
Bird Bombs — spot treatment for enclosed spaces
Flock Free Bird Bombs are a scent repellent that gives you a long-lasting spot application. Each Bird Bomb is a highly absorbent pod designed to be saturated with Flock Free Bird Repellent, so the treatment stays put instead of needing to be re-sprayed.
Soak the Bird Bomb in the repellent solution — the mix rate is 50% concentrate to 50% water — then place it wherever you need to deter birds. They mount easily with zip ties or any other fastener.
They are designed for small, enclosed spaces: garbage cans, dumpsters, warehouses and small industrial facilities. At a fishery or aquaculture site that means the enclosed buildings — feed stores, bait rooms and waste areas — rather than the open water or the perching rails. The Bird Bombs cause irritation that suppresses the birds’ desire to feed and creates a sense of danger in that space.
The 5-pack is supplied on its own and needs Flock Free Bird Repellent separately. The Bird Bomb Bundle includes a single Bird Bomb with a 4 fl oz bottle of concentrate to soak it in.
Choosing the Right Approach
Cormorants come down to one decision: can the water be covered or not? If it can, netting is the answer, and the rest of this page is secondary. If it cannot — and on a large fishery it often cannot — then you work on the perches instead, because taking away the rails, docks and posts they rest and dry on makes the site far less convenient to fish.
If you are netting, size the specification for the birds. Cormorants are large and strong, so support and tensioning matter more than they would on an ornamental pond, and the margins need closing properly.
If you are working the perches, shock tape along the rails and dock edges is the practical route, with the charger chosen by whether you have power at the waterside.
Either way, the scale and the value of the stock will drive the specification, and both usually justify getting it right the first time. Since 2007, Flock Free has been protecting fisheries and aquaculture sites — call 732-987-5400 before ordering for a commercial operation.
Related Bird Control Resources
- Bird Control Tips by Species of the Birds — our guidance across the other species we treat.
- Bird Netting and Accessories — netting, fixings and installation components.
- Shock Systems — shock tape, connectors and chargers.
- Hazers and Sprayers — application equipment.
- Commercial Bird Control Services — for fisheries, aquaculture and larger sites.
Shop by Bird
Flock Free guidance for the other species we treat: