Sunday, February 15, 2015

Over the

If you're at all curious about the ocean, and let's face it you're reading this blog so you probably are, you're most like likely aware of the mola mola. Molas are also called sunfish thanks to their penchant for lounging at the surface like beach goers looking for a tan. 

That's fair, this is about what my thighs look like the first 
time I go out in shorts every year.
Courtesy: Sandip Bhattacharya via Flickr

So if there are sunfish out there, are there moonfish? That may sound like the kind of lame joke your uncle might make at a family dinner, but it's actually a valid question. And yes there are a couple of species commonly called moonfish. My favorite of these, and an animal I only discovered recently, is the opah (Lampris spp.). Opah look a little like mola, but they're completely unrelated.

Oooo, shouldn't have gone with the spray-on tan.

This fish is incredible. Believe it or not they're related to oarfish. If you've never seen them before, oarfish are anything but round and squat. In fact the giant oarfish (Regalecus glesne) is the longest of any bony fish, usually growing to 8 meters. It's believed that giant oarfish originated the legends of giant sea serpents. While they're generally pretty different; if you look at opah and the oarfish (dibs on the band name) side by side you can see a bit of a resemblance.

From Field Book of Giant Fishes 1949 courtesy: Biodiversity Heritage Library 

Both fish have those large dorsal (on their back) fins with a large crest in the front. They've also got long pelvic fins extending down from their bodies. It's going to sound incredibly unscientific to describe it this way but they're also both very shiny. The scales of these fishes are so reflective that their group name (Lampriformes) means the shapes of light. That reflectivity is really useful in both fishes' habitat, the open ocean.

Okay, so why are we not talking the sea serpent one? The opah just looks like someone took a belt sander to the edges of a tuna. Its tail is so small compared to the rest of its body it doesn't even look like it would help the opah swim. Ah, you're right imaginary snarky reader! Opah don't use their tail fin to propel themselves through the water. Instead they use their pectoral fins, flapping them up and down like a penguin! They're also massive, the biggest opah ever caught weighed over 300lbs. Yet despite their size and stubby looking fins opah have been recorded speeding away from predators at four meters per second. That's about twice as fast as most people jog.

In order to move all that mass around opah have powerful muscles behind their pectoral fins. The muscles are so burly that they look, and apparently taste, more like beef than fish; even though the rest of the opah's muscles are similar to those of tuna.

Courtesy: Io [Public domain], via Wikimedia Commons

It's kind of incredible that we have a lot of information about what Opah taste like, and you can find plenty of recipes online, because we hardly know anything about their biology and life history. Opah live in deep water, rarely coming to anything shallower than 50 meters and they don't live in schools. Both those things make them especially hard to study. It doesn't help that during the day when we humans like to be awake, opah spend time at the deepest parts of their range foraging mostly for squid.

Most encounters with opah come from fisher people long-lining for tuna. Long-lining is a fishing technique where several-hundred meter lengths of line are dropped down covered in hundreds of baited hooks. Inevitably something other than the target species gets caught; thinking they're snagging a free meal. This is referred to as bycatch, and many bycatch species aren't commercially valuable, so they're thrown back dead. Fortunately for fishers opahs' tasty meat makes them very valuable and they're able to keep and sell them. You can watch some guys in Hawaii filleting an opah in the video below. Skip ahead to the 2:50 mark to get past the local TV shenanigans, or enjoy the dorky jokes and watch the whole thing.

The thing is we don't know how this catch affects the opah population. Some people think they're safe because there isn't a targeted fishery, and others think we don't know enough to say whether they're being seriously harmed or not. The Monterey Bay Aquarium's seafood watch program, which is well researched, recommends avoiding eating opah from international sources, and only occasionally enjoying those caught in US waters. This is because the US has some of the best fisheries management in the world, and lots is being done to cut down on bycatch.


Lee, Jane, "Rarely Seen Moonfish, Size of Manhole Cover, Caught on Camera." National Geographic: Weird and Wild, February 5th, 2015

McClain et al., "Sizing Ocean Giants: Patterns of Intraspecific Size Variation in Marine Megafauna", PeerJ, 2015, DOI: 10.7717/peerj.715, Accessed via:

Polovina, Hawn, & Abecassis, "Vertical Movement and Habitat of Opah (Lampris Guttatus) in the Central North Pacific Recorded with Pop-up Archival Tags.", Marine Biology, 2007 DOI: 10.1007/s00227-007-0801-2

"Order Summary for Lampriformes", Fishbase

Sunday, February 1, 2015

What is a Seahawk Anyway?

You may or may not have seen that Chris Evans (Captain America) and Chris Pratt (Star Lord) got into a discussion on twitter over who would win the NFL championship today (I can't legally say the name of the event due to copyrights, yay!). Depending on which team wins the big game; one of their superhero personas will show up at non-profit for children with cancer in the other's hometown. Chris Pratt is from North of Seattle, and Chris Evans is from Boston. During the exchange Chris Evans asked a question that's actually pretty common even here in the land of the 12th Man. #whatisaseahawkanyway? Good question Chris, I think this week we'll answer that.

Seahawk (Superbowli repetensis)

It's not always the case with sports emblems, but the seahawk is actually surprisingly accurate to it's namesake.

 You were expecting it to be blue weren't you?
Courtesy: vladeb via Flickr

That bird is an osprey (Pandion haliaetus) and some of its alternative common names are: fish hawk, fishing eagle, and sea hawk. Now don't me started on the hilarious missed opportunity when we didn't call the team the fishawks, but otherwise this bird of prey is a powerful emblem for my home team.

If you feel like you've seen this bird before you probably have. Osprey are distributed world wide, from North to South America, and from Europe across Asia to Australia. The only place where these birds don't winter or breed is in Antarctica. There's only one requirement for these raptors to survive somewhere; fish. 

Osprey are almost exclusively piscivorous (piss-i-vore-us), not unlike that guy everyone knows who claims to be vegetarian, but doesn't count fish for some reason. Fish approaches 100% of their diet with occasional hors d'oeuvres of reptiles, rodents, and small mammals. The grace and power with which osprey catch their prey is astonishing. Their adaptations for hunting would make them pretty great football players as well.

Ugh this guy's Endzone celebration is really weird...
Courtesy: David Mills via Flickr

Osprey begin their hunts by circling above the water searching for the right place to strike. Not unlike Russell Wilson in the pocket, an osprey's eyes are perfectly adapted to find their target in all sorts of weather. The dark bars around their eyes help reduce glare (the charcoal football players use does the same thing) so they can see into the water. Once they've spotted a fish they have a couple ways they can catch it. There's the Richard Sherman style snag where they swoop down and snatch up their prey without getting touched by the water. You may have seen bald eagles do the same type of catch. Or they can go Beast Mode and crash directly into the water, talons outstretched in front of them, penetrating the surface to about 3 feet. This type of hunting is unique to osprey because most birds of prey can't scramble back to flight after getting wet. You can see both styles of hunting in this great video from Wildscreen.

They are so good at holding on to struggling fish because their talons are covered in minute hooks. These dig into the fish and make sure the osprey never fumbles. They also have another unique adaptation that allows them to get back to the air; wrists. They can bend their wings at a joint most other birds can't and that allows them to get lift straight out of the water from a dead stop.

Oh, Wilson's lost in the scrum at the line of scrimmage.
Courtesy: Jeff Bosco via Flickr

But wait he's managed to scramble out for a five yard gain!
Courtesy: Michael Utin via Flickr

So what are seahawks anyway? They're a unique and well adapted predator with all the skills necessary to dominate in almost any environment. Also they're a bird.


Flemming, Stephen, & Smith, Peter, "Environmental Influences on Osprey Foraging in Northeastern Nova Scotia", Journal of Raptor Research, 24(3):64-67, 1990

"Pandion haliaetus, Osprey"
The Encyclopedia of Life

"Pandion haliaetus"
US Forest Service