Working With Your Local Currents – Bill Bowtell
Just about every angler who ventures out onto the ocean has experienced the effects of oceanic currents in some form, or other: be they geographical forces of nature, or locally driven by wind and tide.
Every angler who has fished a creek, river or estuary has experienced the same affects caused by tidal flows in both the daily ebbs and flows according to the phases of the Moon.
Even large bodies of still waters that are found in lakes, dams and other impoundments contain currents at one time, or another. These phenomenon being the direct result of wind and gravitational pulls of the Moon over these large fluid bodies of water.
The remnants of a 4.5m tide as it gently sweeps around the point of Manifold Is. Note that this current drains both a bay and the main channel!!!!
Fish, in all of these circumstances, react to the effects of these currents. Understanding these effects in your local fishing patch can often be the difference between a totally successful day’s fishing, or a day of fishing mediocrity; in some circumstances, even total failure.
My local patch is here on the Capricorn Coast, with its main features being Keppel Bay, the Fitzroy River, Cape Manifold and north through to include Port Clinton, Island Head Creek and the waters east to include the Capricorn Channel and the Capricorn-Bunker Group of reefs and islands. It is a big patch of country covering about 8500K2. The main influence on this large area, which affects much of the water movement, and ultimatelythe fishing, is the southerly flowing Eastern Australian Current. Other inclusions influencing this same area are the cessation of the continuous barrier reef culminating at the Swain Reefs section of the Great Barrier Reef; the gap known as the Capricorn Channel; and,the broken features of reefs and shoals known as the Capricorn -Bunker Group. Local marine charts and Google Earth clearly define these features.
Keppel Bay, a major feature of the Capricorn Coast is a large, shallow, macrotidal bay that forms the interface of the Fitzroy River Basin with the Great Barrier Reef lagoon and the Coral Sea. It is protected on its eastern front by a ring of continental islands known as the “Keppel Group”. Further to the east and sou-east are the intermittent reefs and shoals of the Capricorn – Bunker Group, which include such locations as Karamea, Morseby and Barcoo Banks; Goodwin, Douglas and Haberfield Shoals; Wistari and Polmaise Reefs and the sand cay islands of North West, Tryon, Mast Head and Heron, loosely described as a flooded break away from the continuous barrier reef. Like the rest of the Capricornian waters, Keppel Bay is a complex area of seasonal and annual currents that influence the movement of fish on a yearly basis. It is also indicative of other parts of Queensland’s coastline.
Guy, with Bill’s 12kg Spanish taken from the edge of the current line in the background on Trip #2.
As previously mentioned the Eastern Australian Current (EAC) is the primary current affecting this entire area. It flows south outside of the Great Barrier Reef pushing warm tropical waters from the higher tropics to southern latitude south of Sydney. Along the way, its waters are forced across, and through, the reef and into the inner reefal lagoon. This is due to the influences of the strong South East Trade Winds (SETW), bottom features of the sea bed, upwellings in the sea floor, gaps in the reef and tidal wind drifts. The normal seasonal drift of this inner reefal water is generally south. But there are exceptions. And the Capricorn Coast experiences many of these exceptions. Due mainly to the gaps and intrusions into the broken protecting reef to the east. The second major effect is the continuous run-off of the second largest catchment in Australia and the largest drainage system on the east coast of Australia: the Fitzroy River. When combined, these two features alone push and direct water on a major scale throughout the waters of Capricornia. They also control the movement of fish species. For the angler, it is important to recognize and understand not only the major effects of currents but also the micro, local effects that occur on any given day: right down to tidal movement and wind direction and strength.
The properties of currents, in their many forms, are varied. They have dimension. They are spatially located. They have speed and momentum. They may be cold. They may be warm. These properties may be static, or they may be dynamic. Currents can be complex and hard to understand. Generally the first indication that our days fishing has been affected by a current is a change from our normal fishing. This can simply be a better, or more varied catch; to no fish at all! It may include a different drift direction, or a noticeable change in both water temperature and colour. Effects of currents can be clear cut. They can be diverse.
Fish sitting wide of a Keppel Island bommies over a seemingly featureless bottom. They were juvenile mackerel.
As the major oceanic and coastal currents push along the coast and move throughout the reefs, they interface and impact with local water conditions. Features such as rivers, creeks, bays all carry and display the effects of their own environment and habitat. This can be local sediment run-off from creeks and rivers, open sandy ocean beaches, dense and continuous mangrove forests, such as seen in the Hinchinbrook Channel of North Queensland, rocky foreshores and headlands protecting secondary bays and creeks, such as seen in Capricornia’s Port Clinton and Island Head Creek. Waters from these local areas flow into the inner reefal lagoon where they are mixed in an oceanic bowl of warm, cold, clear and coloured waters with nutrient rich ingredients that provide a food supply for all sorts of fish species. These waters are then dictated to by the tides and wind.
So where does this leave the fisher? It’s ok to have this knowledge, but how can it be put to the best use when out fishing? Or better still, when planning a trip? What is the best way to ensure we maximize our opportunities? Keppel Bay offers typical, but very real conditions, of the affects of currents both oceanic Capricorn to the north and Fitzroy to the south, as well as the effects of the outflow of the Fitzroy River and the local Keppel Group of islands. It is a tidal macroscale that contains most conditions experienced along Queensland’s coast. Two recent trips, mixed with local knowledge, identify the importance of being aware of the benefits of understanding currents and their effects.
Trip #1: In Search of Mackerel – Keppel Islands
Notes from my diary:
High tide at 0520hrs at 4.04m. Moon Rise was at 0138hrs (Brisbane) – Minor Bite time in Keppel Bay approx. 0800 hrs. Wind was SSW at 12knots. Started fishing 0630hrs (5 mins after sunrise). Water temperature: 23.7*C. Location – Conical Rocks area.
I have been fishing the Conical area for Spanish for more than forty years. It has been good to me and I know the area well. However there are times when success has not come my way for one reason, or another. This was my second trip in a week to the area, the first lasting only 10mins with the current one fish in-possession limit for Spanish mackerel. I was home by 0730hrs. This trip was different.
The tide had been on the ebb for just on the hour. There were five other boats in the area; all trolling. None were having success. There were no birds working and the sounder showed little activity in that mid-depth range where Spanish like to hover. My mate, Pete, dropped the downrigger to 8m and I ran a flat line. One bait was bonito, the other ribbon fish. We went looking.
Peter with a nice 8.5kg Spanish taken at Outer Rock at a place I call “The Scallop” for obvious reasons – the bottom formation causes the current to swirl back on itself.
Spanish work the current lines in search of baitfish. That’s what we were endeavouring to do. Tidal currents form where the sea bed rises or deepens into a trough. Features such as coral reefs, rock bommies and sandbars push and direct the tidal flows into pathways along which baitfish move and the Spanish follow. Baitfish also gather at the edges and points of these impacting features. They will stay there for shelter out of the current and for safety from predators. At these times they are also a target. We caught three small undersize fish in near the rocks and bommies of this area over a three hour period. The water temperature had dropped to a cool 21.8*C. There was a cold current inshore of the islands. We moved wider to Outer Rock arriving at 10:30am – two-and-a-half hours after the minor bite time.
The water around Outer was a warm 24.9*C and even though the tide was in the last hour-and-a-half of the ebb there was still a noticeable current line forming as the tide moved past the large rock island. The baits were positioned so that one bait ran just to the edge of the current line and the other, inside of the current by two rod lengths. The line of flow was easy to pick.
Currents in their movement pick up all sorts of matter; debris, fallen, or thrown from shipping and boats, seagrasses disturbed from the sea floor by trawl operations, or storms and logs/timber washed out of estuaries. They all end up being transported along by the momentum of the flow. They are a dead giveaway as to the presence of a current. Similarly currents can be identified by broken, or ruffled water at the surface. These lesser currents can often be harder to identify if the winds are also affecting the surface. If there is uncertainty go back to your sounder and check for bottom features in the area you are fishing. Look for any distinguishing features that will cause deflections. We followed a line of floating sea grass and caught three nice Spanish mackerel, releasing one undersize fish of 61cms.
A common and welcome visitor to Keppel Bay’s Conical Rocks area. I think that the little fella was smiling at me. Mum was not impressed and slapped her tail at him. Whales use the current to great effect!
Trip #2 – Chasing Saddletail Snapper (Nannygai) on the Wide Grounds
The Wide Grounds east of Yeppoon are an extensive area of trenches; sand-drifts; red-fern; low, isolated bommies and rocky reefs and corals. To the west they are bounded by flat ridges of consolidated muds and shale hosting a variety of whips, ferns and isolates. Being the widest section of the Great Barrier Reef lagoon they are strongly influenced by the ensuing currents pouring through the Capricorn Channel, or pushing north through the inner coastal area north of Cape Manifold. From personal experience these coastal currents during the Winter months can run in a northwards direction for many weeks at a time. They can also be very unpredictable and erratic in water temperatures. For the fisher they can be a curse.
S-Cape 2 picked up the inshore current as we motored NE wide of Stockyard Point. The line of debris was the first indicator just on sunrise. The second was when we slammed, at speed, into a floating timber hatch cover lost overboard from some trawl operation. The damage was minimal. The incident itself – bloody scary! The heavy section of timber was dragged aboard so as not to be a further navigation hazard. We motored on as the sun rose arriving right on the top of the tide. Minor Bite time would be at 0950hrs; working 2hours either side of this time would give us four hours of prime fishing time from time of arrival.
Highest Astronomical Tide for 2024 flowing into Fig Tree Creek – Yeppoon. Fish moved at the head of this current.
The fish were found to the north of the shoal. They were out and feeding. This is an important point to note. Fish that are located over and around any form of structure will move according to strength and direction of tidal flow. Tidal flow fixes the schools of bait as they too move about feeding on plankton and zooplankton flushing in by the current. The fish follow. Tidal currents also sweep the sea bed floor, waving soft corals and fern. This bottom movement disturbs squid, crabs, prawns and other crustacea, all food for feeding fish like the nannygai.
The sea on this day was calm. The water temperature was a warm 25.3*C – ideal! We drifted the shoal and picked up several nice fish which included, not only saddletail snapper, but some large, grass sweetlip, cod and a lone pink snapper. After two drifts of the area, the wind sprung up from the south, then went to the sou-west. The water temperature dropped to 21.6*C. The tide, assisted by the wind, pushed our drift pattern to the east and we lost the fish. And try as we might by covering a very large area, we could not find the fish. They too, had moved; forced out by a current change. Checking the area four hours later after fishing marks further out, showed that the current had steadied and the fish had returned. The water temperature had returned to a tepid 23.6*C.
Shelter from the flow – fish such as mackerel and Queenfish will hover in these locations to rest after feeding. They will sometimes bite.
Currents are important features. Fishers need to be aware of their presence and how to treat them. They are dynamic and dictate where the fish will be and when they will be feeding. They play a major role in determining and regulating water temperatures which also affect the feeding habits and movement of fish species. Understand currents, put yourself in the right position and the fish come to you!
