{"id":2914,"date":"2017-09-30T23:26:54","date_gmt":"2017-09-30T23:26:54","guid":{"rendered":"http:\/\/whaletimes.org\/?page_id=2914"},"modified":"2020-10-21T09:28:07","modified_gmt":"2020-10-21T09:28:07","slug":"2914-2","status":"publish","type":"page","link":"https:\/\/whaletimes.org\/?page_id=2914","title":{"rendered":"Jeffrey Drazen and the Rattail"},"content":{"rendered":"

\u00a0\u00a0 Hagfish Day Star Expert Interview<\/h3>\n

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Jeffrey Drazen and the\u00a0Rattail<\/h2>\n

Hi Hagfish Day Fans,<\/p>\n

We’re excited to have one of our favorite biologists, Dr. J<\/span>effrey D<\/span>razen<\/strong> from the University of Hawaii, join us again this year for\u00a0 Hagfish Day! Dr. Drazen is a deep-sea fish expert and part of his very cool career includes exploring the deep-sea in a submersible!\u00a0 Last year he shared his thoughts on the lovely hagfish and the barreleye. This year, he’s back with another deep-sea beauty, the rattail fish. Who wouldn’t love that face? Jeff, tell us more…<\/p>\n

\u00a0\u00a0\u00a0\u00a0 Jake, the SeaDog<\/span> <\/em><\/p>\n

How many kinds of (deep-sea) rattails are there? Which is your favorite species? Why? \u00a0\u00a0<\/strong><\/p>\n

JD:<\/span> There are about 400 species worldwide which is an amazing diversity. My favorite is probably the abyssal rattail (Coryphaenoides armatus).\u00a0 Its found worldwide from about 2000-4500m depth making it one of the most abundant fishes on the planet.\u00a0 Yet, much of its biology still remains a mystery.\u00a0 We have no idea when or where they reproduce.\u00a0 We have found no larvae.\u00a0 We do know now that they are big time scavengers eating lots of dead fish and squid that died in the surface and sank to the abyss.<\/p>\n

My what big eyes they have….why? <\/strong><\/p>\n

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JD:<\/span> For rattail species that live down to about 3,281 ft (1000 m) they probably still see the last bits of sunlight. However, most species probably use their eyes to see bioluminescence \u2013 the light generated by other animals.\u00a0 This would allow them to hunt, avoid predators, and interact with others of their own kind.\u00a0 Some rattails have bioluminescent glands on their bellies, too.<\/p>\n

The rattail\u2019s *pelvic fins look longer than most fish…is there a reason?<\/p>\n

Most rattails (but certainly not all) swim along the seafloor looking for food. Their pelvic fins are long and covered in taste buds so that they can detect prey by skimming across the bottom.<\/p>\n

Pelvic fins are a pair of fins on underside or belly-side of the fish, sort centered between the head and tail. Pectoral fins are pair of fins closer to the eyes.<\/h5>\n

Is it true that some rattails are big-time drummers? Can the deep-sea rattails drum, too? <\/strong><\/p>\n

JD:<\/span> Yes! In many species the males have special muscles attached to their gas bladders (the drum).\u00a0 They use these to drum, making noises probably to communicate to their own kind.\u00a0 This would be a great way to communicate in the dark.<\/p>\n

A rattail’s tail doesn’t look like a rat’s tail to me. (Say that three times fast!) tail. So, what\u2019s up with the name? <\/strong><\/p>\n

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JD:<\/span> A long time ago, scientists thought that the tail of these fish resembled a rat\u2019s tail.\u00a0 This probably was in specimens captured in trawls so that all the scales were rubbed off.<\/p>\n

\u00a0Their long tapering tails don\u2019t allow for fantastic bursts of speed but they are very efficient slow swimmers. This is a big advantage for cruising in the darkness of the deep where food supply is really low. And, are they really called \u201cgrenadier\u201d to make them more appetizing to people?<\/p>\n

Common names change. Fisheries began developing for these fish in the late 1970\u2019s through to today. Nobody wants to eat a rattail.\u00a0 So they are now commonly called grenadiers.\u00a0 That sounds much more exotic and appetizing than rattail.<\/p>\n

According to Monterey Bay Aquarium\u2019s Seafood Watch, people shouldn\u2019t eat grenadier….why not? <\/strong>(Forgot what a grenadier is? Read #5 again!)<\/p>\n

JD:<\/span> The large grenadiers that are commercially fished have a really slow pace of life and won\u2019t be able to survive much fishing pressure. They have very low metabolisms and live a very long time — 50 to 75 years. They also mature late which means the do not reproduce until they’re somewhere between 10-20 years old! Grenadiers (rattails) also have have low numbers of offspring and\u00a0 probably only reproduce once every other year or so.<\/p>\n

All this information is important to understand because, the fisheries for grenadier\/rattails are mostly principally trawl fisheries. Dragging a trawl net along the bottom of the ocean devastates the seafloor killing juveniles and adults alike.<\/p>\n

Is there a safe way to fish for rattails (grenadier)? <\/strong><\/p>\n

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JD:<\/span> Probably not. Where biologists have been able to collect good data about rattails, the fisheries for these species are not sustainable. That means the fish could not keep up with the fishing industry. Fishing for them could cause a collapse in their population.<\/p>\n

Two of our other Hagfish Day, the hairy vent snail and black snail, live in deep-sea vents. Would a ratfish ever run across them in its travels? <\/strong><\/p>\n

JD:<\/span> They certainly come through vent fields but I\u2019ve not heard of them actually feeding on vent fauna.<\/p>\n

Why is the rattail important to its environment?<\/strong><\/p>\n

JD:<\/span> These fishes are relatively abundant, very diverse and often amongst the top predators in the deep-sea, the largest ecosystem on our planet. Can you imagine understanding how the African plains ecosystem worked without knowing anything about lions, cheetahs or hyenas?<\/p>\n

Can people….okay deep-sea scientists…observe them in person on a deep-sea sub or do they live too deep or are they shy? <\/strong><\/p>\n

JD:<\/span> We frequently see rattails from the sub. They aren\u2019t very fast swimmers. You can see how close from the photos (on this page) of rattails taken from the sub.<\/p>\n

\u00a0Some species do seem to avoid lights (shallower living ones) and others seem attracted to disturbance.<\/p>\n

\u00a0In one experiment I was involved with off Monterey we had rattails swimming around the area the whole time we were taking sediment cores, or moving instruments about.\u00a0 We actually bumped into a few of them before they swam off.<\/p>\n

What don\u2019t you know about rattails but hope to learn in your research?<\/strong><\/p>\n

JD:<\/span> There is a lot we don\u2019t know about rattails. Some of my current research is aimed at understanding their metabolism and growth.\u00a0 We know these things are very low in some species but with such a great diversity we don\u2019t know how general this pattern is.\u00a0 Finding out is really important because a slow pace of life means that they are very susceptible to fishing and to climate change.\u00a0 (see #6 and 7)<\/p>\n

Another of my science goal\u2019s is to understand life in the oceans deepest places, the ocean trenches. Rattails are some of the deepest living fishes in the world. They live\u00a0 just over 22,967 ft (7000 m) down! Why aren\u2019t they found even deeper?\u00a0 This may have to do with food supply or with adaptations to crushing pressure.<\/p>\n

Do rattails have any adaptations or behaviors as awesomely cool as a hagfish\u2019s<\/strong>? (though having taste buds on their pelvic fins is pretty cool!\u00a0 (See #3)<\/p>\n

JD:<\/span> Different species have different strategies or behaviors here are a couple. >The abyssal rattail has a very fat rich liver which it can use to live off of between meals. It has been calculated that it can live for about 200 days without eating.<\/p>\n

They are amazing scavengers and show up to bait within minutes even though they are not very abundant at any one location.\u00a0 They can do this because of their amazing sense of smell.\u00a0 (this is very similar to hagfish).<\/p>\n

\u00a0**A special thanks to Dr. Drazen for helping us celebrate Hagfish Day.\u00a0 Dr. Drazen’s research for this interview was\u00a0supported by the National Science Foundation (BIO-OCE #0727135)<\/h5>\n

To learn more about the rattail<\/p>\n