[Fiskadoro]

Originally Posted by monkeyfishturds

I hope there is a better showing of threshers along the coast this spring. I don't know about offshore at 100 fathoms, but in 10 to 20 fathoms i've only seen 6 to 8 foot threshers caught in recent years. In 2006, i saw 10 to 12 foot sharks caught.

I guess it depends on what you mean by big, or adult. You might see some of the larger sub adult fish in Malibu. It's unlikely but possible. Most people think a 10 to 12 foot T shark is an Adult, but they are still sub adult Threshers.

It's really all about the migration patterns.

The larger adults migrate through offshore, heading up the coast around Point Conception and then North up to Oregon and beyond. The smaller, and younger pups migrate inshore moving slower, bunching up in large groups, sometimes stopping for extended periods. Everyone pretty much knows that but now I'm going to tell you something you probably don't know. I think the vast majority of smaller juvenile sharks never leave the So. Cal bite and stay in the warmer waters south of Point Conception.

T sharks are endothermic, meaning they are warm blooded. Water conducts heat away from your body with relentless efficiency much faster then air, so in order to keep their body temperature up T sharks have to eat a lot of food. The colder the water the more they have to eat to stay warm.

Earlier in the thread I talked about how strong adult threshers are. Pretty much everyone who's fished for them or studied them agrees that these sharks once the mature are the supreme athletes of the shark world. They might not be as fast as a Mako but pound for pound they outfight all the other sharks and are comparable in strength to the greatest fighters of the sea swordfish and giant bluefin tuna. Something happens with their biology when they go through puberty and suddenly the are the biggest badass of the sea. It's almost like they are a whole other species.

So why is that?

Why would a shark that feeds mainly on Sardines and Anchovies need to be that athletic? Why would an animals biology and behavior change so dramatically when it get's older. Natural selection doesn't select traits that are not needed, so why are these sharks so tough in adulthood.

Well I'd say it's about the migration. The adult T Sharks round point conception head north following the huge northern sub population sardine migration to their spawning grounds. They have to brave the cold waters of the California Current which runs against them, feed on the move but at the same time keep up with their peers. So unlike the pups which stay in one place for extended periods they are constantly on the move. The water temps are much colder then down here so they have to eat enough on the move to not only keep going but keep their body temperatures up in the colder water. It's kinda like spawning salmon running up a river, or better yet Tuna and Yellowtail. Yellows are tough fish but they can stay in one place, stop feeding, and just hang. Tuna are always on the move and have to eat to survive. It's a more demanding or harsher way for them to live so they have to be tougher and more athletic to survive.

The Pups can't do it they are simply not athletic enough to hunt down enough food to make the journey. So they stay down here in the So. Cal. bite where the water is ten to twenty degrees warmer and they feed on the Southern Sardine population which spawns local. It's actually a brilliant adaption. They both feed on the same things, but while the young ones live in the easier warmer environment and feed local, the adults are adapted to a long migration into a much harsher environment where they can feed aggressively without competing with their young for the same food source.

That's the key. It's about food and survival. That's why the pups have a different migration pattern then the adults, that's why the pups stay inshore and the Adults stay offshore, and that's why the Adults fight so much harder then the pups. They are simply tougher, because they are adapted to live in harsher conditions to survive.

Puberty is a bitch and it can be confusing. Sub adults like then ten and twelve footers your describing from Malibu are not yet true adults. From my experience Ts over 175 pounds generally migrate North with the adults. Then again I always run into them while fishing for adult T's. I have no doubt that the sub adult fish I've seen if left unmolested would of complete the full migration, but do to what I've read about their growth rate, I would guess it was the first attempt.

The Adult Migration pattern is actually pretty well known.

They come up the coast in groups, packs or waves, five, ten, twenty sometimes even hundreds fish traveling together, working bait concentrations on upwellings offshore in deep water. The 9 mile bank, deep water areas off La Jolla, Oceanside, Dana and Newport, all see adult fish every year.

After Newport they swing out to avoid the shallow flats in front of Pedro then cross the channel outside the rigs. They then work North past Catalina but the population splits with some of the Adult sharks working up the front side and some working up the back side.

Those that choose the backside route then head up passing SBI on the outside, circle outside around the channel islands and head up the coast to Oregon. We don't fish those sharks but the commercials get them and they are there at the same times every year.

The fish that go up inside of Catalina cross the 286, the boot, pass east of SBI, follow the inside edge of the ridge up past the hidden reef. They then have another split short of Anacapa like the one at Catalina where some of the sharks cross over the ridge and go around outside the channel islands then up the coast to Oregon, and some others stay inside and go up the channel inside of Cruz in front of Santa Barbara and then round Point conception and head up the coast as well.

None of this is written in stone and the Sharks always are responding to conditions but these patterns are predictable, they happen every year, and fisherman especially the commercials who target them use these patterns to plot their migration and catch them year after year.

All the guys I know that reliably fish adults in the LA area target them out between the boot and the hidden reef more then twenty miles offshore of Malibu. My largest was taken East of the boot closer to the 286, but it was still way offshore.

What I'm saying here is that Malibu is not like Newport. It's not normal stop on the Adult migration pattern, but some larger fish can end up there with the right chain of events. No-one can give you a definitive answer as to why, but I've thought about it a lot and I'll give you my take.

Like I said sub adults or sharks that are 175+ pounds travel with the adults but it's probably their first attempt at the migration. Some years we have really clean water and a ton of fin bait in the area inside the 286 between the 270 and the deep water in Redondo canyon. I think if the conditions are just right those sub adult fish can get distracted follow the bait in feeding on them and they essentially just loose the migration.

These are sharks that probably just the year before worked up the coast tight to shore, so the combination of clean deep water and lots of food is enough to get them off course.

I've seen ten to 12 ft T sharks on bait in Redondo Canyon, I know that occasionally they end up in there, and I think once they are in there they then get confused and don't know how to get back to the main body of the migration.

True Adults who've made the migration before are probably less likely to do this, but sub adults who have not fully adapted to the adult migration pattern might be susceptible and once in the Canyon they are separated from the majority of the migration and are then left to figure things out for themselves.

They have they instinct to continue North so the work North along the 100 fathom curve which puts them on a direct course for Malibu, but when they hit the shallows off Malibu they are caught on the wrong side of Point Dume and don't know where to go next.

Maybe they then mix in with Pups, or if there is a ton of bait in there they might come in tight to the beach to feed before they figure out how to circumvent Dume and continue on their migration. At any rate they sometimes end up in there and that's when you end up getting those larger Ts in Malibu, but it's not something that happens all the time as it's purely a product of a set of unique conditions.

So do true adults 350+ pound threshers come into Malibu beaches? Not normally, it could happen but it's extremely rare. I don't know of anyone whose caught a true adult T over 350 pounds close to the beach at Malibu.

Do some sub adult fish in the ten to twelve foot range come into the beach there? Yes they do occasionally but these fish are probably just lost and it's not part of the standard adult migration pattern.

Are they going to come in this year?

Well that's a good question, but pretty impossible to answer. It all depends on what the conditions are when they pass the 270, at least that would be my take but the truth is there is no way know, or to predict it. The only way to know those sharks are in Malibu is to run into them, that's because it's a random fluke and not part of the standard migration.

So that's my take on the subject Mike. Maybe a little more then you wanted.

Personally I love talking about sharks, looking at data plotting their migrations etc...
I can't wait for another year to go by, so you can bring this up again.