Understanding Tides: How tides affect fishing
WE were out well past the edge of the continental slope in over 300 metres of water trolling for blue marlin. There were a dozen boats within a few kilometres and the morning had only produced a couple of bites for the entire fleet. The water was glassy calm and there was scattered schools of striped tuna and a few birds meandering over the long groundswell. The radio chatter was quite flat, with no sudden excited transmissions, but there was eager anticipation for the upcoming high tide change in a bit over an hour. 20 minutes later two of the boats hooked up to big blue marlin, followed by three more ten minutes later. A minute later my biggest lure was engulfed by a rampaging marlin and we were hooked up solidly. The entire fleet was now getting bites. It took us an hour to land our fish, a solid one around 150 kilos that we released in good condition. During our fight time numerous other fish were landed. An hour later, after missing a bite on the long outrigger lure, things went quiet again.
The above is a repeated pattern I’ve seen many times. When you are well offshore in 350 metres of water, why do the marlin bite on the change of tide? I’ve never had a good explanation of this, and it also applies to black marlin when fishing the bait grounds in shallower water. The relationship between how fish feed and the tide cycle is a complex business that can be difficult to understand. The following article is about some of the lessons I’ve learnt when it comes to planning your fishing around the tide cycle. Regardless of whether you are chasing marlin offshore or flathead in your local estuary, tides are always a major influence. Even in inland impoundments chasing barramundi there is considerable evidence that barra bite on tide changes! For a lot of these tide related bite patterns we know they occur and plan our trips around the tides, we just don’t know exactly why in most cases they feed on tide changes on the offshore grounds.
Most estuaries are a bit easier to read than the offshore grounds when it comes to working out tides. Tidal variation changes markedly across Australia, with areas such as Broome having differentials between high and low tides of over 10 metres. In southern states most tidal movements are only one or two metres. There are basically two types of estuaries and rivers when it comes to tidal movement. Rivers with steep high banks just rise and fall with the tide, open estuaries with big tidal flats move in and out, filling the flats on flood tides and draining back as the tide falls. In these areas fish move up onto the flats and tend to move around a lot more, whereas in a river that stays within its banks fish can hold in one position for the entire tide cycle. This is important when you plan your fishing. One local species that has taught me a lot about tides is the humble flathead. I spend a lot of time chasing flathead and every trip’s plan is based on knowledge of the tides. The estuaries of the Gold Coast have extensive inter tidal zones, and an area where I catch fish at high tide will be dry at low tide.
Flathead are an ambush predator and use the movement of the tide to give them access to the best hunting spots. In areas with extensive intertidal zones the fish move quite a bit in order to find the best places to feed. They like to hunt where there is a bit of flow in the water that moves their prey with the flow. They always hunt facing into the water flow, which is why trolling down current is more effective than trolling into the flow. As the tide rises a lot of the bigger fish move up onto the flats to hunt in shallow water. This narrow water column gives their prey less means of escape. As the tide starts to fall they move into the draining channels where the current flows off the flats. In most places the best flathead fishing occurs on the last two hours of the run out tide and the first hour of the run in. It often goes quiet on the period of low water where the flow stops. When the tide is low bait is concentrated and has less areas to hide in. I’ve found the hardest time to catch my local flathead is between the first and third hour of the run out tide. In steep banked areas where the water just rises and falls this may not be the case as the fish can hold in the one spot throughout the whole tide cycle. When I plan my flathead trips I always have a plan as to where I should be at a particular part of the tide. Good spots on low tide rarely work well on high tide.
In contrast to flathead, many estuary species like to hunt when the water flow slows down. Mulloway always prefer to hunt when the flow is slow. Fishing live baits or big soft plastics works best on the top of the tide as the water slows down. The fish can isolate and stalk their prey more effectively in low flow conditions, and move well away from cover to chase mullet, pike and tailer. When the current runs hard mulloway look for back eddies where the flow slows and they tend to sit close to the bottom chasing bait the eddy current brings to them. Bream are another species that tend to be easier to catch as the tide slows down, particularly in the river mouths when they aggregate to spawn.
Tide differentials are another important factor to take into consideration. In my local waters in winter the high tide at night is often half a metre higher than the high tide in the day, especially around the full moon period. Sometimes these big tides, particularly if it is windy, can dirty up the water and make daylight fishing hard. When fishing for barramundi in tidal rivers tides control most aspects of fishing. On neap tides when there is less water movement the water is generally much cleaner. In places such as the Fitzroy River near Rockhampton fishing on spring tides is extremely hard with lures. The period around the neap tides and the first few days of building tides are generally the best time to fish for barramundi in tidal rivers. I recently fished the 2021 Barra Nationals on the Daly River in the Northern Territory. I’ve been there many times before and have a pretty good knowledge of the place. The tides were building through most of the event. Each day we adjusted our game plan according to the tides. When the tide runs in there is a lot of fish movement, but the water gets pretty filthy quite fast in the downstream sections. Spot selection is a critical choice. When large numbers of big barramundi are using the tide to move upstream you need to troll the run in flow or work the big rock bars where the fish will hold station. When the tide slows try and work gutters and deep holes adjacent to rock bars using vibes or vertically jigged plastics. The freshwater flow of the river dictates how far the dirty water will push upstream. As a general rule, the biggest barra turn up on the biggest tides.
In northern coastal estuaries there are a wide range of species you can target on the coastal flats. Barramundi, threadfin salmon, fingermark and mangrove jacks will all feed up on the flats as the tide pushes up. This can lead to amazing sight fishing in shallow water but the window of opportunity can be quite short. Casting shallow running hard bodies and soft plastics works well as the tide pushes up, but once it floods the mangrove trees a lot of the fish move into the mangrove forest which makes them hard to chase. If you can find isolated clumps of mangroves you can catch more fish. As the tide falls away again fish move back to the flats and working shallow snake drains can be effective at times. Once again, big spring tides can be tricky to fish in these places, particularly if the water is dirty.
On the offshore grounds tides still make a huge difference when it comes to fishing success or failure. Tide changes can be critical for some species, and I think a lot of this relates to changes in baitfish behaviour. Species such as slimy mackerel, even in the absence of predators, often move up towards the surface on high tide to feed. We often find big schools of slimies rippling the surface on high tide feeding on microscopic bait and plankton, and a lot of the bigger predators are tuned into this behaviour. This may be one of the reasons that most marlin species seem to bite well on a change of high tide. As written earlier in this article, it is amazing how many blue marlin bites come in the hour around a tide change.
Some pelagic species, such as Spanish mackerel, bite best when there is a change of high tide an hour or two after dawn. These are prime conditions to chase mackerel, regardless of the technique you use. They also seem to move up higher in the water column around a tide change. I’ve also found that I catch a lot of my wahoo on tide changes as well, and it seems when we are trolling the inshore grounds with lures targeting black marlin, wahoo, dolphin fish and tuna we get a disproportional number of strikes in the hour around a tide change, regardless of whether it is high or low. There is clearly a lot we don’t know as to why this happens, as in deep water current and water flow really don’t change that much. I do know that I’m a lot more confident in my trolling if I’m coming up to a change in the tide.
When bottom fishing for species such as snapper, pearl perch, teraglin and mulloway the change of low tide seems to be a productive time, and a low tide between 8 and 10am is often the most productive period. Once again, I have no idea why this is the case in 25 to 90 metres of water but it is a predictable and repeating pattern. Some days I’ve fished from daybreak with few fish but have hung on a 10am low tide change and seem snapper come on the bite. The same often applies when live baiting for mulloway on the inshore reefs and wrecks.
Tides are a very important part of fishing success and failure, but we often don’t remember the details of past trips when planning future trips. It is important to keep a diary of your trips recording the tides, weather and moon phases. Patterns definitely tend to repeat themselves, and looking back at your fishing diaries allows you to build on your future knowledge and make good plans. Similarly, if you are travelling to more remote places or area that you’ve never fished before, try and get as much local knowledge as you can as to the best tides to fish. Some places in the north are almost impossible to fish on bigger tides.
Obviously, the tides are controlled by the moon, and moon phases, and the tides they create are also important to record. The lead up to a full moon is often a good time to fish, as are the days after the moon. The exact day of the full moon however, is often quite poor for reasons unknown. The take home message is to develop a good understanding of how tides effect your fishing plans, and work out the most productive patterns.