The specimen measures between 7 and 8 centimetres and emerged from the depths to the surface in an “excellent” state of preservation, according to the museum conservator.
Santa Cruz de Tenerife 14 Feb. (Europa Press) –
The specimen of the abyssal species ‘Black Devil’ is currently stored in the wet collection warehouse of the Museum of Natural Sciences (MUNA) in Santa Cruz de Tenerife, where it is preserved in a solution of ethyl alcohol to ensure its condition for research purposes, with the possibility of displaying it to the public in specific exhibitions not being ruled out.
This particular fish, an adult female that typically inhabits abyssal depths, was found very close to the surface, around two kilometres from the coast of Tenerife, although it was in a precarious state of health until its death a few hours later.
At the time of collection from the sea, its health was not “very promising,” as explained to the media by Alejandro de Vera, the marine biology conservator at MUNA, who described the preservation state of the specimen as “excellent” despite its death shortly after being discovered.
He stated that, likely, “we may never know” the reasons why this species surfaced from such depths, but several factors could have contributed, such as being carried by sea currents, suffering from a disease, or being affected by some kind of deep-sea fishing activity.
The species, identified as ‘Melanocetus Johnsonii’, inhabits deep waters, typically between 200 and 3,000 to 4,000 metres deep, with its most distinctive feature being a dorsal appendage that contains bioluminescent bacteria used for attracting prey in the darkness of the deep sea.
Generally, only larvae or specimens in a deteriorated state have been documented near the surface, and the female is larger than the male, reaching up to 18 centimetres.
This discovery is significant from a biogeographical perspective, particularly concerning species distribution and in the realm of genetic analysis that could reveal potential relationships among specimens of this species found in the abyssal environment.
“It can help us gain some understanding, depending on the genetic connections identified, regarding occurrences in the depths of the ocean,” said the museum conservator in comments to Europa Press.
Conservation Protocol
During the presentation of the species to the media, José Carlos Acha, the Minister of Culture of the Cabildo de Tenerife, expressed delight at the “fortunate” occurrence of this specimen arriving in “very good condition”.
Alejandro de Vera further noted the characteristics of this animal, whose sighting is already considered “quite unusual,” since it resides at depths of 200 metres or more. Thus, it is “exceptional” to have encountered it on the surface, and moreover, “alive,” albeit for a few brief moments.
Regarding the hypotheses concerning why this fish was at the sea surface near the coast of the island, De Vera indicated various factors such as sea currents, potential internal ailments, or deep-sea fishing techniques that might have affected it, as this species possesses swimming abilities but “not enough to navigate as they wish.”
“In the initial examination at the museum, the fish was intact,” he added.
Fatima Hernández, the director of MUNA, emphasised to the media the “strict protocols” governing the activities of natural science collections, which house “millions of specimens” of “fascinating” organisms linked to natural heritage and solving research challenges affecting humanity, including climate change and pesticides.
She also highlighted the keen interest of marine biologists in the great depths, from which the ‘Black Devil’ originates, which comprises only around 3% of our known oceans, as most research has focused more on surface organisms due to various challenges.
In relation to the conservation of marine species at MUNA in Tenerife, a preliminary formalin treatment process is employed to maintain tissue integrity, followed by a transition period of 24 to 48 hours before being transferred to a 70% ethyl alcohol solution.
However, this initial phase involving formalin presents challenges for genetic studies, a drawback that usually necessitates prior collection of muscle tissue samples to ensure future analyses are possible.
In the case of the ‘Black Devil’, due to its small size of approximately 7 or 8 centimetres, it was decided to refrain from intervening and to submerge it directly in ethyl alcohol, which preserves the specimen in its intact state for future biological analysis.
Potential Public Display
De Vera informed Europa Press that, in principle, public display of this specimen at MUNA is not excluded, contingent on the exhibition guidelines that the museum periodically establishes.
“Given the media attention it has garnered, we will carefully consider the best approach in the near future to create a small exhibit where it can be displayed to the public for a limited time,” he remarked.
In addition to being immersed in an alcohol solution, ‘The Black Devil’ requires other specific environmental conditions for its long-term preservation.
Thus, the wet collection warehouse at the Museum of Natural Sciences (MUNA) in Santa Cruz de Tenerife maintains temperature and humidity controls that consistently monitor these parameters throughout the year, as noted by Alejandro de Vera.
“The collections must always be kept under the most stable conditions possible: with humidity levels between 50 and 60%, a temperature range of 19 to 20 degrees Celsius, minimal fluctuations, and darkness, as light can damage the specimen’s skin,” he clarified.
