Anglerfish - taking the mating game to a whole new level
Deep sea Anglerfish embrace an all-consuming mating ritual
ONE species of Anglerfish plays a deadly mating game by absorbing its mate.
The female deep sea Anglerfish (certatoidal) is an ambush predator which hunts in the dark depths of the ocean using a ‘fishing rod’ style appendage with a bioluminescent light.
Females lie half buried in the sand or mud as they wait. The light at the end of the fishing appendage is created by bacteria within it.
The light draws prey from out of the depths towards some very impressive teeth. Prey is swallowed down in a gulp.
There are few if any similarities between male and females.
When two become one
The male fish has just one purpose in life - to find a mate. In its quest, it does not even eat, relying upon its giant liver which can sustain it for months. Once it finds a female, it bites into her belly and holds on.
Gradually, the male’s tissues fuse with the female’s body and becomes an integral part of the female. It will now live as a parasite. The females blood vessels begin to penetrate the male's body creating a connection enabling nutrients to move into the male keeping it alive so that its testicles grow.
Anglerfish reproduce by squirting sperm and eggs into open water and it does this once it has both male and female reproductive organs.
Females may have just one parasitic male attached but can absorb up to eight males. The process is known as sexual parasitism.
In its parasitic role, the male relies completely on the female but he still plays an important role by providing a constant supply of sperm ensuring fertile eggs are produced for the rest of her life.
He is vital to the survival of the species. Â
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Research
Encounters with Anglerfish are rare but when scientists first started capturing them, they noticed all specimens were female and that most had parasites attached. They realised that the parasites were the reduced forms of males.
At first, there was confusion as to how the male and female bodies could merge when the immune system is naturally geared to prevent it, but later research revealed some anglerfish species do not have key genes and this makes the fusion possible.
These are bony fish which inhabit ocean depths often at 1000 metres but there is a wide range of depth, which is dependent on the age of the fish, water temperature, and the availability of prey.
While the males of this species appear to embrace a parasitic role, males of other Anglerfish species only approach the female to mate and hunt for themselves.
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