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Understanding fish behaviour

FISH behaviour varies widely. Anglers encounter situations ranging from feeding-frenzies to shut-downs. Some cannot tell what is happening. Others can read the signs but accept things as they are. Far fewer anglers have the knowledge, skills, and tools to change the situation.  

Fishermen do far better by developing an understanding of their target species. Knowledge increases as you spend time on the water chasing a particular species. The ability to recognise what mood they are in is an important feature of this process. In this article, we examine fish behaviour and then describe ways to alter a fish’s state or mood to get a bite.

The ratio of rest to activity will vary between species. Some predatory fish spend much of their existence conserving energy and digesting their last meal. Murray cod are a good example. It spends much of its day hovering under a snag. Jew, mangrove jacks and many other highly desirable species also spend lengthy periods lurking in the shadows.

Regardless of species, this state or mood is characterised by calm, passive behaviour. Worse for anglers, they often rest in some snaggy dark cavern or snag pile where they feel safe from predators. Fish in this mood are probably the most challenging to catch. Often just presenting a lure or bait to them is hard enough! The accepted strategy for these species is to predict “bite-times” and work those periods hard.

Quite a few species are opportunistic feeders. This may be because they live where food is relatively scarce, there are high levels of competition or because of their metabolism.  Pelagic species such as billfish, wahoo and dolphinfish must deal with these issues. They will readily attack anything they can eat because they cannot afford to be picky due to their fast growth rates, the need for calories and the vagaries of the food supply in the open ocean. Likewise, some freshwater streams are quite barren, and trout will examine all potential food items that drift by. Numerous species are opportunistic and can be tempted more of the time than the first category. In many cases this makes them potentially easier to catch.

A few species need to feed constantly. Luderick and rock blackfish, like many omnivores with a preference for vegetation, must graze regularly to take in the amount of nutrients they need. They are nearly always on the chew and can be taken throughout the day.

Popular angling species range from being quite unreceptive for much of the time through to almost constant grazing. Understanding your target’s behaviour is key in designing an effective fishing strategy.

There are other factors to consider apart from food-driven activity. Survival is nearly always a priority for fish. If something threatens, a fish will go into an alerted state. This can vary widely between species. In addition, each species may have a graduated response ranging from ceasing to feed through to panic.  

Different species are triggered by different threats. Sharp noises, shadows, birds overhead or sudden movement are all likely to transform a relaxed fish into a wary one. The proximity of predators such as sharks can place fish on high alert. A struggling fish can put others off while the scent of a recent kill can send the remainder packing.

When alarmed, some species will withdraw further into the shadows or cluster closer together. Schooling species will tighten the group and may flash and dart to help confuse predators. Many fish simply disappear. We know most fish in an “alarmed” state are unlikely to bite. 

Therefore stealth, quietness and associated tactics are recommended. Anglers should always make every effort to avoid scaring fish by using distance and cover.

In some cases, we find fish putting their survival on the line while feeding. This situation is ideal for anglers. Hungry fish are active and aggressive and will often respond to a lure or bait in a very positive manner. Tuna working a bait school are often easily caught because they are presenting a clear target and are not put off by the boat’s presence and actively feeding. You soon notice other predators including birds, sharks, wahoo and billfish are also drawn to the frenzy.    

Breeding fish often throw caution to the wind too. Many species become easy to catch when focussed on reproduction and this why quite a few breeding aggregations are now protected.  

Group competition can also influence fish behaviour. This can be experienced when someone hooks a queenfish and suddenly many more want in on the action. GTs are another example where a group will compete for the lure. 

Environmental factors play a part in fish behaviour. Water temperature, salinity or freshness and light levels are all cited as major influencers on mood and activity. The barometer, moon phase and season all play a role in fish behaviour too although these vary widely between species.

Events such as flooding may cause a scarcity of food and force fish to feed on whatever they can scrounge. Normal behaviour is put on hold, and you can take some amazing captures when fish become “flood sick” or ravenous thanks to a shortage of food.

Anglers soon realise that fish follow patterns of behaviour. For example, most species appear to have a preferred feeding time. This may be at a point when they are less likely to become prey or when numbers make them less of a target. It might be when their preferred food is most vulnerable. Bites times may vary in length and can cease when a meal is taken. We know many species get active with the transition from day to night. Some anglers also endorse events like moon rise, moon “noon” (when the moon is highest in the night sky) and tide changes. Bite times may also be influenced by events such as insect hatches, barometric pressure changes, tides and water temperature.  

Some species’ bite times are reliable while others are harder to predict. When I was regularly fishing the beach, the dusk tailor bite was so reliable I stopped bringing back-up bait.

One of the most puzzling events I have experienced is when predators like blue marlin attack lures over a tide change. All charter skippers know the time to be paying close attention is over the change and while you can get strikes anytime, billfish activity levels go up when the tide transitions. Why do they bite then even though we are so far offshore?  

Conversely, on a winter trip to Copeton, we had trolled for many hours without a hit, much of it over the same few sections of deep rocky bank. Then without any obvious trigger we caught and released three big fish in short order. Why would Murray cod bite aggressively for thirty minutes at two am on a freezing winter morning?

Synchronising your angling effort when fish feed is a well-established method.  Unfortunately, we cannot always be there when this happens.  What can anglers do to draw a response outside those “bite” times?

The first step is to ensure fish are not alarmed as the chances of drawing a bite from fish in this state is significantly reduced. You will see many anglers disregard this vital aspect and plough right up to a fishing spot with the motor roaring. Others create noise, movement and other signals that put fish on alert. Startled, scared or panicked fish are best “rested” for several hours.  

Recently caught and released fish are also far less likely to bite. Apart from the odd suicidal individual, most will spend time recovering from a hook up. In some fisheries, released fish also cause the remainder to go off the bite. Bass anglers will often free fish away from areas they wish to continue fishing to avoid this. 

In most fisheries we are not the only anglers out there. Therefore, we can never be sure we are casting at fish in a receptive state. Recently I worked a series of canals for little only to discover I was unknowingly following another boat that was about ten minutes in front of me. Once we discovered this, we found some fresh areas and started to catch fish.

Anglers should make every effort to avoid working second-hand water, but some areas are targeted repeatedly by many anglers. This pressure may change fish behaviour and even force them to adopt strategies to avoid anglers. Areas that hold “educated” fish will rarely fish well using standard techniques and often require a different strategy.

Swinging a fish’s mood may be as simple as taking advantage of many species’ opportunistic nature. Very few fish will miss the chance to grab a meal if one blunders into range. Those who can cast accurately in close to cover or areas where fish hold will trigger more strikes than those who cannot. The chances are further increased when the live bait or lure behaves in a weak, vulnerable way. On a recent trip to the NT, we watched a school of barra holding tight under a mangrove tree. By casting to the back of the snag and subtly twitching the minnow we got them to bite. In consecutive casts fish “boofed” the suspending lure. They ignored any cast that landed more than a metre out and any lure that didn’t suspend.  Casting accuracy was the key.

For some hard to tempt species, repetition is the solution. Some spots are highly likely to hold the target species, but if a few casts result in no strikes many anglers move on.  Sometimes we can generate a bite by throwing repeated casts from several directions. This goads the residents into a strike. Cod, barra and jacks are all examples of fish that can be annoyed into striking. It takes perseverance and maybe several lure changes, but it is a good way to swing a mood. Remember though, the game is over if the fish becomes startled or fearful so stealth must be maintained. On the other hand, fish like bream and trout will be vulnerable for a few casts but wise up quickly.

Fish will respond to other fish. If they sense feeding is taking place, they may well try to join in. Some lures are designed to create this effect. Poppers and surface lures give off a similar noise to a predator chopping on the surface. Others create foam and bubbles designed to mimic a surface strike. Other lures feature flashing blades that signal to a predator in a positive way. You see this when an angler works a hookless popper to tease fish up for a fly caster.

Some anglers have also adopted the concept of introducing noise or a “sonic signature” into the area. This can be thought of as a type of berley. Technology now exists that generates bait school noises that is emitted underwater. This is said to attract and excite predators.

In offshore game trolling, anglers use teasers to attract predators like marlin and wahoo into striking. Holographic strips mimic a school of fleeing baitfish, a large teaser creates the illusion of a panicked tuna while an array of thrashing squid creates noise, activity and the idea fish are being chased and eaten. Predators attracted to the boat sense feeding is occurring and go from inquisitiveness to striking.    

One of the most effective ways to turn fish into feeders is to give them a whiff of a meal.  Berley has been used by anglers probably since we learned how to fish. By slinging a dead animal in a branch over the water the steady trail of maggots trained nearby fish to feed in the area. Seeds falling from over water foliage does the same thing as does insects that get blown in by the wind.

Berley includes fish food such as vegetation off a rock platform, pilchards, fish flesh, tuna oil and mashed up bread. It is used to attract and stimulate fish into feeding, but it is not designed to feed them. We fished an ocean rock ledge regularly several decades ago that had a featureless sand margin in only five metres of water. Berley was the key.  By lashing a fish carcase to rub on the barnacles, a trail of small particles spread hundreds of metres out to sea and drew in bait including large schools of garfish. With steady application we could convert the whole area into a huge bait banquet where tuna, kingfish and other predators soon turned up. 

Bait scent, bio baits and associated additives are the result of research designed to make farmed fish eat food they would not normally consume. It seems to work, and many anglers use it either in lure form or as an additive on their lures and soft plastics.

Some species develop mating features such as brighter colours. Trout anglers use bright red or orange hot spots on their lures to goad fish into attacking. These spots mimic the spots on rival males and cause fish to nip and bite. Other species will also respond as they look like a dislodged egg. Meanwhile lures in juvenile fish colours also draw attention from adult fish with cannibalistic or protective tendencies.

There may be more ways to get fish in the mood than we know. An old bloke I fished with believed in “waking them up”. He hit snag tops with an oar before lowering a yabbie and amazingly caught yellowbelly and cod during our few trips together. So much for scaring them. This system seemed to be the right stuff in that inland river.   

The ability to influence fish is well worth developing. What mood are they in? Resting, receptive or alert? When is the bite time? Does the target species respond to an opportunity for an easy meal, or can it be excited into biting using berley or other mood swinging strategies? Is my approach giving me the best opportunity to cast at unsuspecting fish? By thinking about these factors, anglers can refine their strategies to improve catches and to better target those trophy fish that elude most fishos. 

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