Are we putting too much salt in our bait? Should we be worried about it?
Many anglers swear by salt as an attractant (bait additive) and they have used it liberally in their baits for years and to make a PVA-friendly mix. But it’s often said (bandied about) that too much salt can be harmful for the environment and the fish: is this true?
Let’s have a little look to find out what’s going on…
Benefits of salt include its natural attraction and the preservation of food bait by inhibiting bacterial growth. For fish it eases stress, reduces osmotic pressure, inhibits nitrite uptake, promotes the slime coat, and helps in healing wounds and the prevention of some disease and parasites.
Salt is made of essential minerals and when in solution are important electrolytes for nerve, respiratory and muscle functions. Any salt used should be free of iodine which is one of the standard anti-caking agents used in some table salt. Iodine is essential for certain plants and animals and definitely of no concern in very low amounts, but significantly more dangerous for fish in higher than trace amounts.
The term ‘Osmotic pressure’ can be best described as Nature’s way of trying to balance the concentrations of a dilute and a concentrate. In the case of fish it’s the water trying to dilute the fish’s own body fluids (which contain salt and other mineral electrolytes) until both sides are equal. Freshwater fish therefore have to constantly eliminate the water – mainly through respiration and urine. The same applies to saltwater species, but in this case the roles are reversed. Saltwater fish have to ‘drink’ water in order to survive. Osmo-regulatory stress can occur during the transport and transfer of fish.
If you chuck some salt into the water what happens to it? Basically, salt is a chemical compound made up of two minerals, namely sodium and chloride – both of which are essential for fish and other life forms in varying amounts. – even slugs, but I am quite sure they don’t like it too much although, admittedly, I am less sure if a salted slug would be any more appetising to a hungry chub than a fresh one.
When salt is added to water it dissolves and goes into solution i.e. it mixes with the water, goes cloudy and then clears. All fine and dandy! However if you add salt to your bait it won’t dissolve so easily or quickly. That’s because the bulk of the salt will be trapped inside your bait and will not, therefore, be immediately exposed to the surrounding water molecules. It will only start to dissolve when the bait starts to break down and lets water in. Contrast this with salt on or near the surface of the bait for maximum/immediate attraction. Like most other attractants, salt works best when it can quickly react with water like when it’s added to a loose ground bait. In fact some of the salt within some hook-baits may not dissolve at all, especially when it’s on the bottom of a salted lake… it could even be rejected or ignored by the fish altogether – and that’s a worrying thought.
Salt also has consequences for PVA mesh and bags too. Just as low temperatures can hinder the melt process of PVA, the accumulation of salt on a lake bed can also retard the breakdown of PVA. In some cases a PVA bag of goodies on the bottom of a small salted lake can actually take longer to melt than if you were fishing in near freezing conditions. Something worth considering as a good indicator of a salted lake in a moderately warm climate would be the glob of PVA stuck to your hook when you wind in.
What is a salted lake?
There are two kinds: a naturally salty/brackish water and a water which contains added salt. A salted lake is a lake which ordinarily would be regarded as freshwater but which has been ‘salted’ artificially by the addition of salt from anglers’ baits over a period of time and, to some extent, industrial runoff. The kinds of lakes I’m talking about here are the ones which aren’t flushed regularly with fresh flowing water. Salting happens over a relatively short period of time where anglers have regularly used salt in their baits in the hope of attracting fish. Salt can indeed be a cheap and effective attractor – but not necessarily good if it’s fished on the bottom of an already salted lake and not if the species it holds are predominantly freshwater species that are deterred by too much salt.
Brackish water by comparison is a natural body of fresh and salt water combined and is tolerable to only some species of fish. Also, some isolated freshwater inland lakes are known to be brackish, especially in some coastal regions.
A few things to ponder over: Salt doesn’t dissipate or evaporate over time – it lingers and accumulates on the lake bed. The speed at which a chemical undergoes a reaction with water is sensed by the fishes’ olfactory system. A slow reaction of salt with water may go unnoticed by fish The salt within a bait may not dissolve quickly enough to be effective as an attractor Consuming raw/undissolved salt is potentially quite off-putting and dangerous to freshwater fish as it burns their gills The potential difference between freshwater and salted water -and depth – determines the solubility of any new salt added.
Salt (table salt) is made up of sodium and chloride ions. The dissolution of salt in water (in solution) means that both the sodium and the chloride are separated from each other and are each surrounded by water molecules. Sodium and chloride can bind to water molecules and they can readily bind with other chemicals to form new compounds. They are important for a variety of biological functions. However, no compound can bind to NaCl (the chemical symbol for salt) in water because NaCl does not exist in water.
Salt (sodium chloride) is made from positive sodium ions bonded to negative chloride ions – just think of it as having the ability to attract like a magnet.
About Sodium (Na):
Sodium is washed out from rocks and soils ending up in oceans where it remains. Seawater contains approximately 11,000 ppm sodium. Rivers contain only about 9 ppm. Drinking water usually contains about 50 mg/L sodium. This value is higher for mineral water. The sodium content in a typical lake depends on geological factors as well as the addition of salt by anglers and will vary widely. Sodium is one of several essential electrolytes required by fish.
The chloride ion is the most common form of chlorine and is one of the two elements that make up table salt, a.k.a. sodium chloride (NaCl). Chloride is an essential electrolyte, responsible for maintaining acid/base balance, transmitting nerve impulses and regulating fluid in and out of cells.
When dissolved in fluid, salts tend to break apart into their component ions, creating an electrically-conductive solution. For example, table salt (NaCl) dissolved in water dissociates into its component positive ion of sodium (Na+) and negative ion of chloride (Cl-). Any fluid that conducts electricity, such as this, is known as an electrolyte solution: the salt ions of which it’s composed of are then commonly referred to as electrolytes.
Difference between seawater and freshwater?
The average salinity of ocean water is 3.5 percent (by weight) which means that a litre of seawater contains 35 grams of dissolved salt. The salinity of different bodies of water hinders the majority of organisms from thriving in both salt water and fresh water. Some plants and animals survive in one type of water but not the other.
Another considerable difference between the two is their density. Salt water has a higher density than fresh water because of the sodium chloride it contains. Cold salt water is denser than warm salt water, but it becomes less dense when water freezes into ice. The boiling point of seawater is higher than that of pure water, and its freezing point is lower. The density of salt water is 1.025, while freshwater’s density is 1.0
Does dissolving salt in water change the pH?
No, at least not in pure water it doesn’t, so no change in pH. However, to arrive at the correct answer in a pond you would have to consider a few different scenarios which would be far too complex for a fishing forum. Suffice to say if you have ever tested your water you will find different readings throughout the day/night and throughout the water column. This is mainly due to other factors such as respirations and excretions from the inhabitants and the vegetation which all play their part. The relevance being that freshwater fish prefer to live in a slightly alkaline environment, that is, a pH of 7.0 and above – not acid.
A heavily stocked fishery will suffer more from ammonia and acid spikes, of which salt, to some extent will counter some of the effects. Salt generally works to rid the blood of excess ammonia and prevent nitrite take-up.
pH stands for ‘Power of Hydrogen’ and is a measure of how acidic or alkaline a liquid is. pH ranges from 0 to 14, with 7.0 being neutral. Example: lemon juice has a pH of 2; pure water a pH of 7 and drain-cleaner a pH of 14. The pH of natural seawater is around 7.5 to 8.4. Fish kept in a typical saltwater aquarium will live happily in a pH ranging from 8.0 to 8.4 with stability being the key in all respects. When water comes straight out of the tap, it is usually close to neutral or mildly alkaline (exact values will differ based on your geographic location). A sudden change in pH is detrimental to fish and continued exposure to high or low pH is likewise harmful. Carp (cyprinids) thrive at the 7.2 – 7.6 range.
A number of sodium compounds such as salt (sodium+ chloride) do not react as strongly with water as with elementary sodium metal, but are strongly water soluble. Na has a +1 charge and the O in water ~(-0.4); the charge attraction causes water to form a sphere around sodium ions.
When salt dissolves in water the sodium and chlorine ions separate. The positive hydrogen end of the water molecule attracts the negative chloride ion. The negative oxygen end of the water molecule attracts the positive sodium ion. The overall density of the water molecule increases and causes it to sink to the bottom of the lake. Therefore, because dissolved salt sinks, the bottom of a lake can be significantly more salty than the top layers which explains why PVA sometimes takes longer to dissolve than it does in a glass of tap water at home. There’s also a few other peculiarities which I’ll try to cover later, but essentially what you and I and a few thousand other anglers puts in, cannot be taken out.
In fact freshwater actually ‘floats’ on top of saltwater as seen in this lab demo:
All this suggests that a bait with added salt would work at attracting fish much better fishing ‘up in the water’ or mid depth on a zig where there is less salt density, and therefore a greater potential for a chemical reaction. Perhaps the best explanation is that salt doesn’t dissolve in an already salty water environment as quickly or as efficiently as it does in fresh unsalted water, assuming a deep lake heavily fished (salt regularly added by anglers) and only a few stockies to mix it up.
By the same reasoning, salt might not have any effect on a shallow lake already containing anglers’ salt at concentrations of one per cent – at any depth. One per cent is the ideal concentration for cyprinids. Also, a bait – whether its salted or unsalted laying on the bottom of a salted lake – will, in theory, take a lot longer to break down and will therefore be the least attractive to fish. The reason I say this is because a salted lake will likely contain fewer virgin water molecules to act upon the bait which is necessary for a bait to become soluble. In fact a bait fished up in the water will break down faster than on a lake bed where the salt is more concentrated but is probably insignificant on a typical shallow lake with an average depth of just a couple of metres.
Another thought to consider: the freezing point of salt water decreases as salt concentration increases. In other words if you add salt to ice it will melt it.
In a salted lake heavily stocked with relatively mobile fish, it is likely it won’t freeze over so quickly as a natural, unsalted lake of the same size and depth. Often the deepest parts of a lake in summer are the coolest as sunlight is diffused and the top layers and margins warmer. This is particularly noticeable on the rare occasions when the sun shines in winter. But in freezing conditions the bottom of a lake (still liquid but without flow or much sunshine) containing an accumulation of salt, might in fact be one of the warmest parts of the lake precisely because of the salt – where many fish like to hang out. Could the reason they sit there have anything to do with the salt, or just above bottom/mid water if the concentration of salt is more tolerable?
Targeting fish dead bottom of a salted lake is probably NOT the best place to put your hook bait… try the layer above!
Every lake contains salt to some degree. Knowing its concentration might be of benefit not only to the management of the fishery and the environment but also as an aid in locating the fish. As for adding salt to your bait, I would say that it’s more likely to work to the angers advantage on a deep lake or a lake where angling pressure is less intense compared to a heavily fished shallow lake. In all other cases a salt-laden bait will be best fished up in the water where the reaction of the attractant has more potential to react with virgin water molecules.
Sadly however, the vast majority of modern, shallow commercial venues preclude the potential for salt to work effectively in what is likely to be an already salted lake with a concentration of one percent or more.
However, all is not lost on the attraction front…. yes I’m babbling but this is important, and you don’t need to understand all the chemistry behind it. There is a viable, nay a much better alternative to salt which is especially suitable for salted lakes or where you suspect high concentrations of salt has accumulated over a number of years. I’ll just say this for now… it’s TWICE as good as salt!
I’ll cover that and more in SALT Part Two, including how to roughly determine the salt concentrations in your lake with a bit of magic pi and approximate guesstimating. Knowing how much is already in there will help you make some informed choices on your next home-made and future bait purchases. I will also discuss a couple of natural alternative additives to use and in what circumstances to use them. Please don’t be deterred by anglers who say additives don’t work; the most important thing you need to consider is WHY and HOW additives work.
See the Laguna Fishing Products website….
To comment on this article, go to…