Melanocetus johnsonii:
As mentioned briefly previously Melanocetus johnsonii has adapted a method of aiding predation by utilizing one of the products of bioluminescence; light. Positioned above the fish’s mouth via a modified dorsal spine is a photophore containing a large colony of bioluminescent bacteria, this particular photophore mimics smaller possibly more desirable third party organism; a behaviour know as aggressive mimicry.
The tip at the end of the fishes dorsal spine is able to move independently from the dorsal spine allowing it to mimic and adjust to any present ocean current, in addition to this the luminescence of the bacteria is controlled by the fish allowing for a range of rhythmic emissions of light. M. johnsonii have also adapted a protruding jaw which is accompanied by long sharp teeth, therefore anything that investigates the fishes lure is liable to be eaten. |
In fact there are a large amount of other organisms which use Bioluminescence in this manner, for example the Black Dragon Fish (Idiacanthus atlanticus). Why do these organisms use this technique when they could just go and hunt their prey? To answer this question it needs to be noted that there are some other largely stressful factors within the bathypelagic zone. For example biomass availability reduces, in correlation, as the depth of the ocean increases, this is due to the reduced energy supply to the base of the food webs; primary producers. This may explain the behaviour of predators within the deep-sea environment, waiting for prey to come to them is much more of an effective method with regards to energy conservation than exerting energy hunting the prey.
The Stoplight Losejaw (Malacosteus niger):
The Stoplight Losejaw (Malacosteus niger) has also evolved an incredible method of utilizing bioluminescence to aid its predatory behaviour. In relation to other organisms M. niger is able to emit short-wave, blue, bioluminescence.
The reason why organisms use mainly blue colours, with regards to bioluminescence within the Bathypelagic zone, is due to the fact that blue/purple has the largest frequency and thus the largest concentration of photons within the visible spectrum; allowing them to transmit further in water. Consequently deep-sea organisms have a wavelength maximum absorbance relative to the furthest emitting light in water, thus reflected in the common short-wave bioluminescence. |
The Stoplight Losejaw (Malacosteus niger) has however evolved an incredible method of utilizing bioluminescence to aid its predatory behaviour. In relation to other organisms, M. niger is able to emit short-wave, blue, bioluminescence however it is also able to emit long-wave red light. But why is this so impressive? Well due to the fact that red light is not able to reach down to the bathypelagic zone most organisms have lost the ability to visualize red colours, all except M. niger. In addition to being able to emit red light, M. niger can also visualize it, thus meaning that this organisms is able to light up potential prey without them even knowing; as they can’t see!