What happens when carp can't shed their spawn?
It looks horrible and we're guessing it must be painful, but what causes it?
Remember those classic shots of Roddy Porter and Alex White with the fish that broke Chris Yates long-standing British record? Well, if you don't, look above. As you can see, it was hugely spawn-bound and shortly after the second capture (Alex White) the fish sadly died. So why does this happen to some carp and is there a way to help carp avoid it in the future? We asked fish expert and angling tutor, James Anderson to fill us in...
Why don't some carp shed their spawn?
"For a carp to spawn it must have several environmental factors in place. These are warm water (18°C for several weeks), good water quality, aquatic weed, no disturbance and a good food supply for the months prior to spawning. Like us, carp are individuals so some may spawn at lower temperatures or some may get more stressed than others, any of which may lead to an individual fish not spawning just because it's a little more 'fussy'. Eventually some carp may also stop spawning due to old age, something that happens to us all!"
How unhealthy is it for a carp not to shed its spawn then?
"If the environmental factors are not correct the carp will not be majorly affected by not spawning. They will wait for when the condition are correct. It's when conditions are very changeable that can stress the fish out, for example if the conditions seem correct and then a sudden drop in temperature."
So how many years can they go without shedding their spawn?
"A female carp can go for many years without spawning, even its whole life. This can happen when no males are present or when the other environmental conditions are not correct such as lack of spawning substrate."
Once they do shed it, how much weight can they lose?
"The ovaries can account for up to 15-20% of a female carp's body weight, so a 20lb female could lose as much as 4lbs in weight. This could be well over a million eggs depending on the fecundity of the individual."
If they can't shed it, will it kill the carp?
"Simply not spawning will not kill the carp. If the fish doesn't spawn due to the temperature not being warm enough for example they can just reabsorb the eggs. Problems start to occur if the physiological processes for the release of eggs are put in motion when the environmental conditions change suddenly. This could be a drop in temperature or oxygen depletion. These changes in environment put a huge amount of stress on the fish which can cause heath problem. If the eggs don't get fully eliminated from the body they can begin to 'go off' and cause bacterial infections which can be fatal."
