THE OBJECTIVE OBSERVERS TACKLE TUNA
In the third installment of Objective Observers, Derek and Jason discuss yellowfin tuna, a fish being mentioned often in the news right now. The angler who caught the all-tackle record yellowfin will be awarded a substantial prize during the upcoming Fred Hall Show in California.
J: No worries, D. I thought it ironic (I'll tell you what that means later) that you called me a butthole when you were the one being mean. Anywho…
D: I'm looking forward to meeting up with you in California next week. I think you said you guys are going out to award that 400-plus-pound Yellowfin Tuna at Fred Hall right? That thing was a beast!
J: Yes, it will be great to see you and the BD folks in Cali next week. I really do like mixing it up with people who fish differently than I do, and I love learning new things, so this will be a blast. Plus, getting to shake hands with Guy Yocom and congratulate him on a phenomenal catch will be a real pleasure. I don't care what you fish for or how you fish for it, you've got to give this guy some credit for that catch.
D: Personally I love everything thing about Yellowfin Tuna. As an artist I'm inspired by their form and colors. As an angler, everything about them makes them a prize. The bite, the fight and ooooohh man, as a potential fat guy, I love eating them.
J: Potential???? You also modestly forgot to mention that you're a pretty gifted naturalist in your own right. You're totally right though. How could you not be in awe of any tuna, especially a yellowfin.
D: You have any interesting facts about yellowfins?
J: I could bore you to death on yellowfin cocktail trivia, but true tunas in general are very, very highly engineered animals. Their swimming form is different from most other fishes, which makes for a potent combination of stamina and burst speed. If you're a fish living in a tuna's neighborhood, it pretty much sucks to be you.
D: I love the way tuna are so streamlined. The dorsal fin slides right onto a neat groove. The pectoral fins lay back into grooves. It really is so fascinating.
J: You got it. Tuna are the model of hydrodynamic form. Think about it. They are shaped like footballs. All the muscle is up front and the energy is translated to a very large, crescent-shaped tail through two very large tendons. What this means is that muscle contractions occur in the front of the fish and are transferred to the rear of the fish very efficiently. The body moves very little side-to-side while swimming, which reduces drag. Instead, you have a big half-moon tail that beats with relatively low side-to-side amplitude, but with incredibly high frequency.
D: Did I read somewhere that they will glide downward sometimes to save energy?
J: Tuna are termed “ram ventilators”, which means that they have to move forward in the water to respire. Contrast this to something like a grouper that can sit on the bottom and flare its mouth and gill plates to get enough water passing over the gills. It's analogous to having an old carburetor on your dad's station wagon compared to a turbo on a sports car. Tuna will make periodic oblique dives in the water column to conserve energy and respire.
D: In most places I have fished for them, they seem to be abundant. What's the state of the fishery?
J: Yellowfin tuna have a couple of things going for them over their bigger, colder water cousins bluefin and bigeye tuna. They are pretty much found worldwide in tropical and subtropical waters, and they spawn at earlier ages throughout the year and in less discrete locations. This makes them less vulnerable to commercial overexploitation. Unfortunately they are a high-dollar fish, so we need to manage them better.
D: Have you ever noticed that the fish in the Gulf of Mexico have the longest dorsal and anal fins?
J: I can't say for sure but I have some colleagues that have forgotten more about tuna than I'll ever remember. You have to remember that fish, to some extent, are like most other animals. Some individuals have longer (I won't mention names) anatomical features than others.
D: By the way, do you know how they got the name Allison fins?
J: I sure don't but I do like knowing why people call fish what. All I can tell you is that the genus for yellowfin, Thunnus, is Greek for tuna.
D: Is there a difference in Pacific and Atlantic yellowfin tuna?
J: No, yellowfin found in the Indian, Pacific and Atlantic oceans are the same species.
D: What's your favorite way to eat a yellowfin?
J: Honestly? At your place with Cory and Alden: sushi or ceviche style. We both like to cook but you kick my ass in this genre.
> See past Objective Observers installments HERE.
What do you get when you put a marine biologist (Jason Schratwieser) who also happens to be a passionate (if not opinionated) angler in a boat with a carefree artist (Derek Redwine) who would just as soon catch a redfish on a hunk of stinky crab than on a hand-tied fly? Some great conversation, that's what.
Join this "odd couple" as they explore the marine world together... sometimes side by side, and sometimes through candid, often controversial conversation.