Guide to deep dropping
Deep drop fishing is a form of bottom fishing, but rather than targeting inshore areas where you can easily use most styles of reels, the depths fished range from 100 to 650 metres! Fishing offshore waters requires specialised gear and techniques which differ significantly from targeting snapper in 10 metres of water.
Deep dropping can be a daunting and challenging style of fishing, but very rewarding once the correct techniques are learnt. The best thing about deep dropping is that most fish you will encounter are delicious to eat!
TARGET SPECIES
HAPUKU
Hāpuku or hāpuka (Polyprion oxygeneios) are a slow growing species, which can grow to 60kg+, although most caught are around 15-25kg.
Also known as groper in New Zealand, they’re available right around the country, and along the southern coasts of Australia, from Sydney in NSW, to Rottnest Island in WA and around Tasmania.
They favour reefs in depths around 200m of water, but they can also be caught in shallower and deeper water.
The reefs and banks around Three Kings Islands, White Island and the Ranfurly Banks in New Zealand are known hotspots.
The edges of the continental shelf off the west coast of New Zealand, and the deep offshore reefs around the continental slope across the southern coast of Australia are prime fishing locations.
Larger fish (adults) are usually found around reef structure, but smaller fish (juveniles) may be caught out in the open over mud or sand.
BASS GROPER
Closely related to hāpuku, the bass groper (Polyprion americanus) is a large wreckfish which can grow to over 100kg in weight and 2 metres in length. The New Zealand all-tackle record is 86.2kg. Bass groper are most commonly caught weighing about 15kg and 80cm in length.
Bass groper are heavily built and have short, round heads, with a lower jaw that projects slightly. They tend to be darker brown in colour, grading gradually to grey-brown on the belly. Juvenile fish can feature pale bands or mottling.
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Adults usually inhabit deep rocky reefs at 100–900 metres (most commonly at 350-700 metres), juveniles (up to 60cm long) are pelagic, and can be found higher up in the water column, commonly near floating debris.
They’re found in Australia from Brunswick Heads in NSW, up to Fraser Island in Queensland, and around to Perth in WA, including Tasmania.
In New Zealand, you’ll find bass groper in shelf and slope waters of the North and South Island, and around offshore islands, from the Kermadecs to the Auckland Islands.
BLUE EYE TREVELLA OR BLUENOSE
Known as Blue Eye Trevella in Australia and Bluenose in New Zealand (Hyperoglyphe antarctica), they will bite and fight harder than any of the other bottom dwelling species. There’s usually no mistaking when you have one or a few on the line, as they will head shake and fight persistently almost to the surface.
They’re commonly found around offshore reefs or areas where the sea floor slopes steeply, particularly in depths of 100-500m.
They favour the east and west coast of the South Island (NZ) but can also be caught up the east coast of the North Island as well.
In Australia, they’re found along the southern coast from South Australia around to lower NSW, including Tasmania.
Bluenose are one of the most sought after species of all the fish you can catch down deep, due to their outstanding eating qualities.
They can weigh up to 40-50kg, but most are caught between 4-10kg.
PINK LING
Pink Ling (Genypterus blacodes) are a demersal species that inhabits the continental shelf and slope. They can be found at depths of 20‑1000metres. Juveniles tend to be found in shallower waters than adults.
Pink ling live over a variety of substrates, from rocky reef to soft sand and mud in which they burrow.
They can grow up to 1 meter long and weigh up to 20kg, but most caught weigh 1-5kg.
Pink Ling can be found along the south coast of Australia, from Albany in WA around to southern NSW, including Tasmania.
In New Zealand, Pink Ling are most commonly found around the South Island.
BLUE GRENADIER OR HOKI
Blue grenadier (Macruronus novaezealandiae), known as hoki in New Zealand, are a cooler water species.
You'll usually encounter blue grenadier/hoki beyond the continental shelf and they're most abundant in 300 to 600 meters but have a very wide depth range. Fully grown adult fish have been found in shallow coastal bays and out to sea in depths up to 900 meters.
Juveniles can be found in inshore nursery grounds from a few meters deep out to about 200 meters. As juvenile blue grenadier/hoki mature, they gradually move further out into deeper water, congregating near the sea bed during the day, moving up into the water column at night.
In Australia, they’re found along the southern coast from Cape Naturaliste in WA, around to southern NSW, including Tasmania. But is most commonly targeted off the coasts of Tasmania and Victoria.
Hoki can be found all around New Zealand, however they're more common off the coast of the South Island particularly in Cook Strait, off the West Coast, the Chatham Rise and the Campbell Plateau.
GEMFISH
Gemfish (Rexea solandri) are a bottom dwelling species that are generally found in large schools on the shelf edge as well as on the slope, particularly over the harder bottom. They are found around New Zealand and the bottom half of Australia. They can grow up to 1.2 metres in length and 15kg, but most weight 2-6kg when caught. When they are thick, big numbers can be caught in a single drop, and have a distinctive sharp tapping bite.
IMPERADOR
Imperador (Beryx decadactylus) are a distinctly bright red in colour and are commonly found along the east coast of Australia, including Tasmania, and occasionally north of New Zealand. This deepwater species may be encountered as by-catch when fishing in waters off the continental shelf and are harder to target specifically They can grow up to 60cm long.
BAROTRAUMA
When fish are brought up from the depths, usually quicker than they would surface under their own power, they can suffer barotrauma. The risk of barotrauma is generally increased as the depth increases. Symptoms can include their stomach being pushed out through their mouth, bulging eyes, bloating of the stomach, and protruding intestines.
Some fish will not show signs of barotrauma but can be suffering from internal injuries such as a ruptured swim bladder, damaged organs, internal bleeding, and clotting.
There is a lot of advice and some guidelines on how to “safely” release a fish suffering from barotrauma, and we suggest you do your own research.
Many deep-water species can’t be successfully released under normal circumstances, so any fish boated must be retained.
The good old recommendation of “only catch what you need” stands true.
Once you’ve either caught your bag limit, or what you want for a feed (within the bag limit), stop fishing.
If you still want to continue fishing, change the style of fishing to either trolling or fish in shallower water where you can catch fish which aren’t affected by barotrauma and can be released if necessary.
GEAR SET UP
ROD AND REEL
Your rod and reel set up needs to be heavy duty. Due to the depth you ‘re fishing in, heavy sinkers or weights are required to get your bait or lure down in a timely manner. Remember not only are you contending with the depth of water, but you also have other factors like the wind, current, and tide to take into consideration. Therefore, heavy weights require a heavy duty rod, capable of putting up with the strain of a heavy sinker as well as multiple fish fighting on the line. The best rods should have plenty of strength in the butt, but a sensitive tip to pick the slightest of bites.
A 24-60kg stand up game, bent butt or 300g+ weight jig rod is recommended. The style of rod will depend on the rod holders fitted to your boat, as well as how you want to fight the fish, i.e. leaving the rod in the rod holder as the fish are brought up, or holding the rod.
The reels will need to possess a good level of drag output, a high retrieval ratio, and have a high spool capacity. If you plan to hand crank then overhead reels are the ideal choice. Electric reels are ideal for deep dropping if you don’t feel like winding in hundreds of metres of line with a heavy fish on the end of it, and they’re now fairly affordable. Electric reels will allow you to do multiple drops on a mark much more effectively than hand cranking on conventional reels.
You can read more about deep dropping with electric reels here.
MAINLINE
Most deepwater anglers recommend using braid instead of monofilament line. This is because braid has very little stretch, providing you with more sensitivity to bites. A rainbow braid is ideal as it helps you know how deep you’re dropping, with colour changes every 10 metres and markers every metre.
Braid also has a very thin diameter for its breaking strain, which means that you can fit a lot more on a spool than using the equivalent breaking strain monofilament.
The thin diameter also means you’re less likely to have slack in the line which fishing at deep depths, which allows you to fish more effectively in rougher conditions, and maintain contact with your bait or lure.
This will result in better hook up rates than if you were using a monofilament line with much more stretch.
LEADER
Because of the unknowns your leader will face at depth, and the fact that the majority of deep sea fish have sharp teeth, it’s recommended you use an abrasion resistance monofilament leader with a minimum breaking strain of 200lb.
When retrieving fish from depths, many fish can spin in the water column as they come up, which not only results in higher abrasion on the leader but also twisting and kinking. A tough heavy leader like our 300lb or 400lb Tough Trace will withstand the abuse of deep drop fishing. When you’re deep dropping, the species you’ll be targeting generally are not shy of coarser leader materials given the low light conditions.
Thicker diameter leader can be harder to tie solid knots with, so using crimps is a good option to ensure your rigs or lures are connected securely.
HOOKS
Recurve or circle hooks are a must, in sizes 8/0 or bigger. Because of the distance between you and your hook and bait, you’re less likely to feel the bite, making it near impossible to strike to hook your fish.
A recurve hook will self-hook the fish when they swim off with your bait. Our KLT® hooks are ideal for deep dropping because they are a finer gauge and have a razor sharp tip, meaning it doesn’t take much pressure for the hook to pull into the corner of the fish’s mouth.
If you see your rod start to load, simply wind up a few turns to put on some gradual pressure and pull the slack out of the line. Then wind gently until you’re sure you’ve hooked your fish.
RIGS
A dropper, ledger or paternoster style rig will work well at depth.
Because it takes so long for your bait to hit the bottom, you want to increase your chance of a fish being on the line as much as possible. So always use the maximum number of hooks you are legally allowed to have on one line. This could vary from 2 to 5 hooks depending on the country/state you're fishing in.
Deep dropping rigs can either consist of a main monofilament backbone with individual monofilament snoods which can be clipped on and off, or a three way swivel connection with the five snoods permanently attached to the rig.
Snoods can be clipped on and off, making it easier to replace any which get chaffed, and to change the size of the hooks quickly. It also means that if you hook a shark or something bigger, you can unclip some of the snoods to make the leadering process easier and safer.
BAIT
Deep dwelling fish generally aren’t fussy eaters. Bait selection should be based on two things - scent and durability.
If you can tick both boxes, then that’s the ideal bait. Some good options are skipjack tuna, squid and kahawai/Australian salmon.
You want a bait which has a decent amount of oil and blood filtering from it which will help bring fish in, but it also needs to be tough enough to withstand the long drop to the bottom and the chance that smaller fish with teeth may pick at it.
The hardest part is making sure the bait can stay on the hook long enough to hook a fish. Cutting you bait into strips makes the more streamlined, which can assist with a quick drop, but also helps with natural bait presentation and movement throughout the water column, which will further entice the local fish.
Remember to match the size of your bait to the size of the species you’re targeting. If you want to target bigger fish, use bigger baits. Whole fish and squid can work for most deep sea fish, and you’ll filter out the smaller pickers doing this.
SINKERS
The sinkers you choose will vary depending on the depth of water you’re fishing in, but they can weight from 700g to 2kg.
If you use a sinker that is too light, it will take a longtime to reach the bottom, or you may not reach the bottom at all. If it does reach the bottom, you’ll also have trouble maintaining contact with the bottom.
If you a choose a sinker which is too heavy for the gear you are using, you will struggle to wind in an empty rig with no fish on it, and the rod will also seem like it’s straining excessively.
So your first few drops may just be about testing your gearset up and see what works best for the depth you’re fishing in, and any current or weather conditions you’re dealing with.
HOW TO FISH
The ocean is a big place, so to help you identify some good spots to fish you’ll need a bathymetric chart application, either on your phone, or on your GPS plotter.
With this alone you can start to have a few trial drops, even without reading the bottom. However, having a sounder which is suitable for these depths is a big advantage, as it allows you to mark bait and fish.
Before you head out fishing, it’s worth spending some time working out exactly where you plan to drop. Do this by inspecting your bathymetric chart application and start looking for areas of interest on the continental shelf. Look for the area of ground closest to the boat ramp you plan to launch from, then start to inspect the contour lines. Look for kinks and sharp bends in the lines on the shelf slope, as well as canyons (multiple circles), which could indicate bait-holding structure which in turn could potentially attract the target species of fish.
When you head out to fish these marks, take note of whether you catch any fish on them, and if you do, what species they are. Some fish will prefer the hard edge of ledges and drop offs, while other species will congregate over the flatter, muddier substrate. You will begin to see these patterns when you start to drift around different areas of the continental slope.
Once you have your spots marked out, and your rigs sorted, it’s time to put everything into practise.
When looking at your depth sounder, bait or fish will appear either as a “furry” layer over the bottom, or a thick band in mid-water or just above the bottom, which can be anywhere from 50 to 300 metres thick.
This layer is known as the “deep scattering” layer or the “scatter” layer and is an accumulation of various organisms which can include lanternfish, squid, hydrozoans, and pelagic tunicates. All of these organisms are sought after prey for deep sea bottom fish, so seeing a thick scatter layer on your sounder is a very good sign.
This doesn’t necessarily mean you’re guaranteed to catch fish, as sometimes the predators are not present or they’re simply not willing to take a bait, but it’s always worth doing a prospective drop even if there are no signs of life present on the sounder.
When dropping your baits down, be aware that you will probably let out more line than the depth you’re fishing in, due to the excess slack in the line from the deep depth. To reduce the slack as much as possible, ensure you use an appropriate sized sinker for the conditions, use braided line, and reverse back on the line if needed, so it drops as close to vertical as possible.
If you see a scatter layer on the sounder it’s worth stopping your bait in that zone to see if there are any fish feeding within it. More often than not, if the bottom fish are present they will stop your sinker from dropping when they grab the baits, which will appear as though you have reached the bottom prematurely. If this happens, flick the reel in gear, watch the bites, and wait for the rod to load up then start the retrieve.
If the current or wind is strong, it will be necessary to continue to back up on the bait to stay in contact with the bottom. It’s also useful to continue to let line out frequently. However, if you’re catching fish in the mid-water scatter layer, reversing is not essential as you can allow the bait to drift up in the water column. By using these principals, it’s still possible to deep drop effectively even in average conditions, in wind speeds up to 15 knots. It just won’t be overly comfortable on the boat!
The hardest part when deep dropping can be interpreting the bites and knowing when to start the retrieve. It’s difficult to know whether one set of bites is from an individual fish, or multiple fish attacking the baits.
To set the hook when you feel sets of bites, retrieve at highspeed for a few seconds, then stop the bait. If you get more bites, then repeat this process until you’re sure you have something hooked and you can start the retrieve.
If you want to prospect more of the bottom you’re fishing in, simply take longer drifts, and make note of what species you catch at particular stages of the drift. If you label the marks on your plotter by species, you will soon have a good pattern of species/structure in that particular area of the continental slope.
Deep sea fish can come on and off the chew with the tide and time of day, so don’t write a spot off completely simply because you didn’t catch anything on it on a particular occasion. It’s worth fishing your spots at different times of the day, but also mix it up by moving between spots spread over the shelf.
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