Ideas about using OpenROV to eliminate lionfish?



Hey Manny, thanks for your reply and the link. The trap looks interesting but must be for shallower water with live fish. Bermuda is a little different than the Caribbean, as we have found larger numbers at deeper depths, so far - much more info needed in this regard.

Thanks for your offer to help, I would be happy to post drawings of my ideas for the deep sea artificial lure - if modeling it would be helpful for construction, that would be great - especially if you could create models that could be used by 3D printing for the parts.

BTW my 3rd idea for catching Lion fish with the ROV (constant slurp hose to boat) would be a lot easier to use at shallow depths (where most problems seem to be in the Caribbean) and the hose (slinky-type wire reinforced) would probably only need to be 6" in diameter. The suction mechanism would look something like an oversized manual bilge pump (with stop screen and evacuation from one-way valved T at btm). Sucks in when the ROV arm is positioned in front of a Lion fish (use an artificial fish in front of the nozzle for a lure?) and on the down stroke, the one-way flap at the front end of the hose closes and the water is dumped through a strainer on the boat. With only 20-30 feet of this kind of hose, it should not be too hard to handle and store on a med sized boat. If this sounds interesting, I could also draw out the simple plunger/pump design, if needed.


Ted yes that sounds like a lot of fun in this fight. I can help with all the 3d. Regardless if you want me to model a part to be print or any sort of illustration or animation.

We can eradicate the lion fish from our waters!


Hi All, I have added a 'slurp hose' design concept to this forum for review & comment. I also added two of my latest design ideas for a deep sea fish lure - feedback is appreciated

1959-SlurpVacume.jpg (1.49 MB) 1960-LionFishLure1.jpg (2.11 MB) 1961-LFLure2.jpg (462 KB)


Here is my third design idea for a deep sea lure...

1958-LF3.jpg (660 KB)


hi, I dont know if anyone has played airsoft or has seen a airsoft gear box but i believe this would be a perfect way to reload spear. here is a video detailing a airsoft gear box and how it works My idea is to have a very high torque motor and gears incased in water tight gearbox. the shaft would have gear teeth running up it and would have a stop so that it could be reloaded easily. I also would like to be apart of this rov lion hunter. great thread.


Thanks for the idea! That's a good idea . Any idea is more than welcome so we finally get the first prototype going! Cheers!


Yes those designs are really sophisticated. That's a lot of work. Yea we should implement one this ideas and then test it in the waters to see how goes. Cheers Ted!


Yes the day we can finally make one of this and fisherman see it as a profitable way to get Lion Fish. That will be the beginning of the Lion Fish in out waters.


The slurp vacuum seems like a good idea but I worry about the weight of towing that pipe around. I wonder if it possible to have a spring loaded piston suction device (think large fish sucking up small fish) that fires fish into a mesh bag or holding tube.


I have been thinking about an ROV fisher for some time now. Love reading all your ideas.

Could you use a stainless steal gas strut- powered by a diving air/ co2 drinks cylinder? loaded by a solenoid valve and triggered mechanically.

Reload by dumping the gas or pumping it back into the cylinder and a small motor- attached to the spear via cable could retrieve the fish and reset the strut position.


Dear David,

sounds like a great idea, however, you need to make sure that the recoil of the harpoon doesn't move back or, even worst, turn the OpenROV to any side. After all, the weight of the OpenROV is not much larger than the weight of the harpoon, I assume...

Hope this helps - David


This is the collection of stuff i am hoping to turn into an ROV.

Ip cameras, arduino+ ethernet. 6 brushless thrusters, Water filter housing to store air at 100psi to return catch and gas
compansate. Will twist tether like rope with nylon cord to reinforce.

Catch arm -telescopic fishing rod with a drain spring up the middle fed and returned by a brushless motor. Spring should coil itself up in a cylinder. Its just an idea at the moment but im working on it.

Not sure how close you can get to a lion fish but a telescopic spear might be easier to aim and retrieve.

Bulking up the rov with a bigger payload might allow enough stability.


ok, that looks really interesting. Nice thinking.

Re: proximity to lionfish. If you haven't taken a shot at one, they could care less and you can get within inches. However, if you shot and missed, then it's a lot harder to get close for a second chance.

So basically, don't miss! :)


Hey David,

Exciting that you have compiled some parts and have a concept in mind! I agree with Jack and that you can get quite close to the lionfish without spooking them. Hopefully over the next couple weeks I'll take my OpenROV and try to find a couple lionfish and will see how close I can get before they move away.

I would test your spear idea before going too deep into your ROV design, just to prove it. One concern that I would have is the driving force that the air provides and how it will decrease with depth (as the differential pressure decreases)

One idea I had for dealing with the recoil of the spear on the ROV was to have a tail/fin like object that would be parallel to the water during normal operation and then it would rotate 90 degrees, presenting a large flat surface to help induce additional drag when you were about to shoot.



The filter housing contains 7 litres. So if P1 X V1 = P2 X v2 then ((100 psi X 7litre )/14psi= 50litre of gas at sea level? working at a depth of 30m the presure is 42psi so the differential pressure is 58 psi so V2 = V1 X P1 /P2 or V2= 100 X 7 /58?

So It might be 12litres at 30m depth? Just a guess- might need to deduct the volume of the rov? If it is 12l that would displace 12kg of water and fish must be about neutrally buoyant so there might be enough air inside.

If anyone understands Boyle's law I would love to here an explanation of this problem.

Im hoping to catch scalops with the rov- to provide an alternative to dredging that is accessible to everyone. And what i have been thinking is floating the fish up to the boat in batches of 5 by inflating a lift bag that is loaded in a rack of 5 possibly returning 25 fish up the tether. Then the rov would be pulled back and the 5 floats reset in the rack.


could you slurp it into a net?


Have you seen this research project? - I guess it's worth supporting, because it will probably also reveal behavioral patterns of the lionfish...


wow, nice to see his campaign so successful, and he's right here in Massachusetts! Lots of folks are doing similar work but I'm wondering now if we should crowd source a version of the OpenROV for lionfish removals....thoughts?


Maybe a bad idea but it seems to me that if recovery of the fish is secondary and the lionfish is as unafraid as it seems… Wouldn’t it be easier to have a fast spinning motor attached to a rod/axis (maybe 50cm long) and at the end of the rod have two knives (like an aeroplane propeller). Get the knives close to the fish and trigger the motor… Lionfish tartar!


Hello all.

OpenROV engineer here. I’ve been reading this thread a bit here and there. Today I feel like weighing in as the subject of spear fishing lion-fish came up in an email to me today.

Frankly, I think it is a terrible idea- inefficient, ineffective and a bit hostile. Obviously this part is my personal opinion, but I don’t think waging a technological war against fish that live in crevices in the ocean is something we have the upper hand in.

Please consider the logistical details of this venture. I know it sounds like a great idea, but I would never consider spear-gun fishing from an ROV to be an effective population control mechanism, unless of course the process from deployment to bringing in the kill was entirely autonomous- even then I think the idea deserves scrutiny.

Realistically, if you are hunting lion-fish, then you are probably in some sort of coral reef. Coral reefs contain a lot of fragile corals. How will you aim the spear gun accurately (amidst ocean currents) and make sure you don’t damage the very coral you are trying to save by killing lion fish? You will need to surface and redeploy the ROV for every shot fired. That takes a very long time. You get one shot every time you go down. In addition to the ROV, which has a tether of its own that requires a second person to make sure it doesn’t sink and get caught in corals, the spear gun will have its own cord that will need to be retrieved. If you aren’t William Tell of ROV spear-fishing, the spear will likely get stuck in a small rock (of which there are A LOT of in coral reefs), how then will you remove the spear? If you simply pull the ROV that it is attached to it then you are running the risk of breaking all the fragile corals in the path of your spear cord, which would be a heart breaking thing to do, if you care about the health of coral reefs.

If you are just trying to go straight up spear fishing, then it could be a cool project. Just don’t deploy it in our precious reefs.

I’m just trying to be as forward and direct as possible. I appreciate that everyone here is applying their mind to solving the lion-fish issue, I just don’t want to see OpenROV’s cause any damage in the very ecosystems we are trying to passively observe.

That all being said, I haven’t brought anything constructive to offer in terms of solving the lion-fish epidemic. I’m just chiming in regarding spear-fishing lion fish.