how likely do you think that this technology is will spread to other aquariums? Does it depend on how well it works in France?
Small, heavily pressurized deep water tanks have been used before with various levels of success under laboratory conditions. I think its spread among public aquariums mainly depends on how many aquariums are willing to pay $$$ for an exhibit that has great potential from a scientific point of view, but most normal aquarium visitors probably would find average. Or perhaps even less interesting than a normal coral reef aquarium that could be made at a fraction of the prize.
Do you think that aquariums really might display animals like the species you mention
Much of this is obviously speculative:
Deepwater tripod fish: A reasonable contender. Fairly small, inactive, have a relatively broad depth range (=they're not extremely specialized in depth) and found widely around the world (=a reasonable chance that an aquarium could get one, if they really made a serious effort with a sub). I suspect the primary issues would be the long fins and its carnivorous behavior. Capturing it without damaging the fins could be difficult. It probably can't be kept with larger fish that are too boisterous, as they would risk damanging the fins. Smaller animals could well appear like prey items to a tripod fish. That means you have a very expensive deep water aquarium with perhaps only one inhabitant.
Rattail: Perhaps the best contender among the groups I mentioned. Medium sized and could probably live with other species seen with some regularity in deep water tanks (Japanese spider crab, small sharks, deep water rock fish, etc) without major problems. Have a very broad depth range, from a few hundred meters to several thousand meters, and occur in a wide range of habitats. Common to very common in most deep oceans around the world. The first fish seen on a deep water submarine dive is often a rattail. If I remember right Monterey Bay Aquarium attempted keeping rattail years ago but didn't succeed. The knowledge gained since then combined with a pressurized tank could be the tipping point. With the developements in recent years, I wouldn't even be all that surprised if a Japanese aquarium has a rattail in a few years time in a
non-pressurized deep water tank. Unlike the other fish examples I have mentioned where I suspect a pressurized tank is a must.
Viperfish: Less likely than the two above. Even more carnivorous than a tripod fish = very expensive deep water aquarium with perhaps only one inhabitant. Additionally, viperfish are more of an open water group = require a larger aquariums than a similar sized fish that spends most of its time on or near the bottom.
Pelican eel: Least likely of the four I mentioned. Open water and very carnivorous behavior as in the viperfish. Unlike the three fish groups mentioned above sightings of the pelican eel are extremely rare. Based on catch data it isn't an exceptionally rare species but the usual techniques used by scientists to see living deep water creatures are evidently not suitable for this species. It is only quite recently that I saw the first photo of a living pelican eel (not the usual dark photos of museum specimens that are common). If scientists are struggling to get a photo of a living pelican eel, the chance of capturing one alive for an aquarium is tiny.
In summary, good contenders would probably be: Relatively small or medium sized, found at a broad depth range, widespread and regularly seen on deep water submarine dives, not extremely carnivorous, and typically found on or near the ocean floor (benthic).
Grimpoteuthis (or
Opisthoteuthis?) was kept at
Monterey Bay Aquarium in the 1990's and
Opisthoteuthis has been kept at
Enoshima Aquarium in Japan (
backstage w. light switched on shortly, note isopod neighbours). Both Monterey Bay and Enoshima octopuses were kept under normal surface pressure, though I don't think the Monterey fared too well. The Monterey has apparently (?) still not received a formal scientific description and I have seen it listed both as
Grimpoteuthis sp. and
Opisthoteuthis sp. Most use the former genus (e.g.
MBARI and Norman's book on cephalopods) but I'm not sure if anyone knows for certain where it belongs. So either a true Dumbo (
Grimpoteuthis) or a close relative (
Opisthoteuthis). It even laid eggs during its captive life in Monterey Bay Aquarium. In this group, the Monterey octopus is a "shallow" water species from around 300 m/1000 ft and deeper (about the same for the Enoshima
Opisthoteuthis). Most true Dumbo octopuses are generally found well below 2000 m/6500 ft. Often much deeper than simulated in the Oceanopolis tank. This combined with the rarity of sightings make them some of the least likely deep water octopuses for aquariums.
In general, invertebrates like octopuses and worms are far better at dealing with pressure changes than vertebrates like fish. Except for the ultra deep water speces, most deep water octopuses may even be possible in a deep water tank with normal surface pressure. One major problem is that most octopuses and squids have very short life spans, rarely more than 2 years. It has been suggested that the general failure to keep mimic octopus, a tropical shallow water species, hasn't really been a failure but its normal short life span. Of course it is possible that the virtually unknown deep water species live longer but I suspect not: Even the Humboldt squid, a very large species found in fairly deep waters, usually only lives for about 1 years. Getting a submarine to catch a Dumbo octopus from below 2000 m/6500 ft would be extremely expensive and you would need a lot of luck to get one on first attempt. Just imagine then realizing that it only has a few months left of its natural life
