American Fisheries Society - Report

Greetings NCKA Members,

I've been more of a lurker these days on this site.  However, I had the opportunity to attend the annual American Fisheries Society Meeting in SF this year in SF and heard some talks regarding things most likely of interest to NCKA members.  I'll present brief summaries by subject, and please excuse the fish-nerd talk:

Steelhead  Sean Hayes and his crew working down on Scott Creek near Santa Cruz have pulled together some interesting data on steelhead rearing patterns in small California coastal creeks.  He found that most of the successful fish that return to spawn (86%) reared (grew up) in the estuary, not the actual stream itself.  He found that estuarine reared steelhead grew twice as fast as stream reared fish, and could end up being twice the size as stream fish at the same age.  This was all done with PIT tags.

A grad student working with him suspected that the nutrient input into the bar-lagoon system to run the bioenergetic processes came from kelp that washes over the bar. And to test this she looked at stable isotopes in fish flesh from the estuary and from upstream fish and found that the estuary fish had the isotope structure closer to marine fish, not river fish. This suggests that kelp wash fuels the critters that fuels the fish, and its more productive than upstream conditions.

Cabazon A guy doing research on cabs (also using PIT tags) off of Morro Bay founds some interesting things.  We've all (yak-fishers) suspected this, but it appears that cabs don't move around a lot from their home range, which is generally around 200 m².  Most of the recaptures of tagged fish were within 50 meters of the original capture location.

To test their homing abilities, he translocated fish up to  2 or three miles away from their original capture location (I think) and the 52 fish he recaptured were all found within 100 meters of original capture location.  I'm not sure what time of year he did this, but clearly they're homebodies at that time.

Juvenile Rockfish Indices  The NOAA research vessel David Starr Jordan give a bleak report on offshore juvenile rock fish abundances for 2006 and 2007.  This almost 50 year old ship has been sampling with drag nets at the same offshore locations for 25 years.  And in the past few years, they've increased their sampling grid up and down the coast.  They found that abundances of all the commercial species of rockfish babies (all the ones we target and more) vary fairly uniformly by year.  That is all species all go up or down pretty much the same by year, which indicates they're all influenced by the same oceanic (upwelling) conditions.  The abundances for the last 2 year were the lowest since the ship started working this sampling method.  This suggests that in 5-6 years when these fish mature, rockfishing may suck.  I was particularly bummed to see my old fall-backs, blues and blacks, right in there with the rest of them.  There are other reasons why it may end up not being too bad, but the point is that there were few babies in the last two years........which also brings up another interesting but gloomy subject:  Humboldt Squid.

Humboldt Squid  Researchers on the David Starr and three other speakers all presented clear observations that Humboldt squid are vastly expanding their range and numbers.  Additionally, they prey on just about everything of all different size ranges, which is looking like a another big setback for rockfishes.   I'll say right now that I have to eat my hat on this one.  I was one of the first to condemn the seemingly wanton overfishing of these animals by the party boats.  But from what I'm hearing, well, fish away.

These squid used to range in the the gulf of California  up into southern CA.  They now can be found in numbers up to Sitka AK, and don't appear to be affected by the cold:  One guy showed a pic of a big squid next to an iceberg.  The real distressing thing about these guys is their growth rates.  Their life span is 18 months, and in that time they go from plankton sized organisms to over six feet.  One presenter made the analogy of going from human baby size to blue whale size in 18 months. This takes a lot of feed.

Besides the enormous growth rates, these cephalpods are amazingly fecund, producing many young.  So there's a lot of them and they eat a ton. Additionally, because their generations are so short, an average rockfish living 25 - 30 years may have to suffer through 20 generations of these things, which reduces their survival to reproduction ratio considerably.

Oddly, the squid can reside in the Oxygen Minimum Layer (OML), a depleted oxygen zone about 200 meters (I think , again) in depth where fish generally won't go due to O2 depletion.  They hang out there to avoid predation, then vertically migrate up to the fish levels for carnage.  They feed more at night, but are not nocturnal by any means.  For some reason as yet undetermined, they don't mind low O2, which is unusual for squid.

One speaker had two hypothesis of why this is occurring.  Reason 1, which he didn't seem to give very much support, is that the heavy take of top-water predators, the natural predators of squids, have lessened limiting factors on the population.  Reason 2 is that climate change has raised the OML and pushed it more inshore.  I didn't quite understand all of this, but the speaker was putting more money on this scenario.

The only good thing that can be said about them is they may provide more of a prey base for sperm whales and mako sharks.

Hope NCKA members find this information useful......and kill more squid.

Thanks for the report.

I wasn't able to attend this year but Jim "InSeine" Hobbs and Naoaki are there.  The steelhead stuff is pretty cool, the cabezon stuff not surprising at all and the rockfish and squid info simply depressing.   I'm a pretty firm believer in the oceanographic/climate change hypotheses for both the rockfish declines and squid increases.

Brian

Cabazone A guy doing research on cabs (also using PIT tags) off of Morro Bay founds some interesting things.  We've all (yak-fishers) suspected this, but it appears that cabs don't move around a lot from their home range, which is generally around 200 m².  Most of the recaptures of tagged fish were within 50 meters of the original capture location.

To test their homing abilities, he translocated fish up to  2 or three miles away from their original capture location (I think) and the 52 fish he recaptured were all found within 100 meters of original capture location.  I'm not sure what time of year he did this, but clearly they're homebodies at that time.

So to sum it up....they swam home?

-Brian G

So to sum it up....they swam home?

-Brian G
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Yup, almost to the exact spot.

Thanks for sharing.........can we put Humboldt squid in Hobies and have the landlord eat them????..........

Hey Pescadore:

Thanks for the report.  I was at the same talks as you.  We should have meet up for a beer. 

I would like to add some thing as well.

First. There was a session of MPA's, several off whom where old friends for graduate school.  What I was very surprised to hear was that they really had no clue that the MPA's where being drawn up for the North Central coast this year and that much of their work to optimally design MPA's, particularly in California where waste of time. rt  But what was most interesting was a talk from a fellow at Santa Barbara working on this huge multidisciplinary projuect called "Fish, Flows and Fisheries.   Basically they are a group of oceanographers that have been studying the central coast.  This study has shown that because the oceanography in the area is so variable, due to these large eddie currents that at a year to year scale it is pretty much impossible to predict where babies land onshore, but over the lifespan of a rockfish. due to randon probability the entire coast line will receive larvae.  This means that as long as we protect habitats the MPA's produce fish and that the more productive sites will obviously produce more fish than less productive habitats.  This makes me laugh because it is one of the those "duh" kind of things, but people are knocking themselves out (myself included) to figure out where the big momma's are and where their babies end up.  But this makes me feel better about drawing circles on a map.

Jim

Hey Pescadore:

Thanks for the report.  I was at the same talks as you.  We should have meet up for a beer. 

Jim

I would have liked that.  I think there there were over 3000 folks there, and I knew maybe 10.  Thanks for the MPA information.  Us yak-fishers should wear armbands or something.

Great meeting, but I couldn't go too much talks except work related ones (I was helping out too much)...
I wanna thank you to Sean for his donation tho (I didn't win, but what's new...)!  That made raffle sells alot easier.

No problem!  The yak was won by an HSU student...can't feel any better than that!!!