Thresher Conservation Debate - Kayak Fishing Adventures on Big Water’s Edge

FISHIONADO · 08-30-2010, 07:24 PM

I recognize there are strong feelings on both sides but I'm interested to hear arguments for and against taking threshers, either pups or breeders. We should be able to disagree in a civil manner. I apologize for stirring the pot when I was defending a guy on another thread, I was sort of an ass. Owe some of you a cold beer on the water.

Definitely interested in seeing other sources of information. This is what I found when I first considered the topic.

NOAA National Marine Fisheries Service:
http://www.nmfs.noaa.gov/fishwatch/s...n_thresher.htm

Pacific Common Thresher Shark (Alopias vulpinus)

Sustainability Status

Biomass: Unknown; preliminary analyses of common thresher shark catch in the pelagic drift gillnet fishery operating off the U.S. West Coast indicated that the biomass in 2000 was above the biomass supporting the maximum sustainable yield (MSY).

Overfishing: Unknown; Preliminary analyses of common thresher shark catch and effort in the pelagic drift gillnet fishery operating off the U.S. West Coast indicated that the catch-per-unit-effort of thresher sharks was increasing in the late 1990s above historical lows experienced during the early 1990s. Thus, in the U.S. West Coast EEZ, it was estimated that the local population of common thresher shark was not experiencing overfishing at that time, and the population may have been rebuilding.

FISHIONADO · 09-01-2010, 05:29 AM

Maybe there is no debate on this subject? Someone mentioned in another thread that their friends were trying to get the DFG to change the rules on threshers. Anyone have the data they were using?

I'm interested because I have released threshers in the past because I thought they were endangered based on the opinions on all the fishing forums. But my own quick research says they are at sustainable levels in Southern California. Is it just an emotional thing or is there current scientific data to support "no take"? This is the same reason I fought the MLPA so strongly, I want regulations based on science and not emotion.

Peace all!

dos ballenas · 09-01-2010, 10:46 AM

check this out:

http://www.bloodydecks.com/forums/ca...ase-first.html

the current status of the population is unknown... but likely is at sustainable levels.

But, like Black Seabass, threshers are susceptible to overfishing.

Sharks are known to live for a long time. They are slow to grow, have very few babies, and don't reach reproductive maturity until about 4 years old. Harvesting young pups and large breeders are two things that could have a negative impact on their long term sustainability.

Thresher sharks are also known as ram ventilators, which means they have to be swimming forward in order to breath. This is a problem because many times they get hooked in their tails. Threshers like to hit their prey with their tails to stun them. This results in tail hooking and during the fight, the sharks are dragged backwards through the water. As a result, many sharks are fought to the point of exhaustion, and when released, some do not survive.

Many people feel that recreational sport fishing pressure on threshers has increased in recent years due to the sharing of current fishing reports on the internet, and the fact that thresher sharks are very easy to hook. The possible results from an increase in recreational fishing pressure have not been studied.

The are no regulations on sharks fishing currently. That means you can keep as many as you want, of all shape and sizes. That doesn't mean that you should.

There are many reasons why keeping threshers is controversial, and many reasons why some sort of regulation may be implemented. Most reasons are based on the biology and life history of the animal.

FISHIONADO · 09-01-2010, 11:55 AM

Great input, thanks. Do you have any idea what the major threats are to threshers and where kayak fishing ranks?

I've never targeted them, always figured I would take one if it was by-catch and drowned or was the right size for me to land alone.

CurtyL · 09-01-2010, 12:16 PM

my take is pretty simple. If I'm not eating it I'm not keeping it. I don't like T so I don't keep them. I do try and get my hooks back though.

dgax65 · 09-01-2010, 12:46 PM

I wouldn't mind seeing more restrictive limits on thresher and mako. The only problem is that more restrictive limits on recreational anglers are pretty much pointless when there is long-lining going on just outside of our waters. Commercial long liners probably take more in a day than the entire yearly recreational catch. Its too bad mako aren't cute like dolphin. If they were, the PETA/Greenpeace/Sea Shepard douchebags would be all over it. Stop buying shark, tuna, swordfish, rockfish....from the market and convince all your friends and acquaintances to do likewise and maybe we wouldn't have to reduce the recreational take limits.

Regor · 09-01-2010, 05:53 PM

Quote:

Originally Posted by dos ballenas

The are no regulations on sharks fishing currently. That means you can keep as many as you want, of all shape and sizes. That doesn't mean that you should.

Oh yeah, there's a limit, better check your DFG, not that any of us in our yaks have much of a chance of going over :

"The bag limits for shortfin mako shark (Isurus oxyrinchus), thresher shark (Alopias vulpinus), and blue shark (Prionace glauca) allow take of two fish per day with no size limit."

Ohana · 09-01-2010, 08:10 PM

FISHIONADO:

Thanks for starting this topic. It is definitely something worth having a good discussion about.

Having fished for Threshers for the last 10 years, I would say that the fishery from recreational fisherman pressure has increased due to the increase in number of boaters (especially in the middle of the last decade) and the relatively close inshore nature of the sharks has made them easy to target for a larger percentage of fisherman (no long travel using up expensive gas). I know that when I first started catch and release of T-sharks, you rarely heard about it on the local fishing boards, but as more people started posting the knowledge of this fishery, when was the optimum time to fish, techniques/locations, and the ease at catching them, it seemed like every spring everyone who had a boat was out trolling for T-sharks and were showing off their catch being weighed rather then releasing the sharks.

Does this have an impact on the fishery? Hard to say as removal of certain numbers may actually improve the health of the population as there is less competition for food/ decreased cannibalization increasing the recruitment size. But considering that T-sharks give birth to living young, their litter size is small (2 to 4 pups), and that they take between 7 and 13 years to reach sexual maturity would make them more vulnerable to overfishing then other large gamefish, such as marlin, swordfish, and white seabass which produce large number of eggs and mature at a faster rate. As off the Southern California coast it appears to be the T-shark pupping grounds, both newborn, juvenile, and adult sharks can be caught year round, resulting on a potential overfishing impact to all populations of growth stages of the T-shark.

Based on my observations the last 10 years and the fact that we humans lack certain levels of self control (i.e. how we got into the current economic mess

) ), I am for a limit on the number kept and setting the maximum size of 150 lbs that can be kept by recreational fisherman. I choose a maximum size as the idea is to increase survival of the breeding class and that a small/medium T-shark (<150 lbs) is plenty of good meat.

Please note that I am strong believer that recreational fisherman are low on the scale of threats to saltwater fish populations; habitat destruction, pollution, and commercial gillnet/longline fishing are far and away the biggest threats.

Thanks again for starting this topic and I look forward to reading other peoples responses.

Kevin

FISHIONADO · 09-02-2010, 06:00 AM

If anyone here supports slot limits maybe they could explain the benefit of releasing the smaller threshers. Is it because they are too easy to catch? Agree Kevin it's nice to see a civil discussion on this topic. I have a lightly supported opinion that threshers from SoCal are a sustainable resource based on the NOAA website, but I'll flip flop in light of compelling information.

I always refuse shark fin soup during biz travel to Asia. And chicken feet....

08-30-2010, 07:24 PM	#1
FISHIONADO Senior Member Join Date: May 2006 Posts: 698	Thresher Conservation Debate I recognize there are strong feelings on both sides but I'm interested to hear arguments for and against taking threshers, either pups or breeders. We should be able to disagree in a civil manner. I apologize for stirring the pot when I was defending a guy on another thread, I was sort of an ass. Owe some of you a cold beer on the water. Definitely interested in seeing other sources of information. This is what I found when I first considered the topic. NOAA National Marine Fisheries Service: http://www.nmfs.noaa.gov/fishwatch/s...n_thresher.htm Pacific Common Thresher Shark (Alopias vulpinus) Sustainability Status Biomass: Unknown; preliminary analyses of common thresher shark catch in the pelagic drift gillnet fishery operating off the U.S. West Coast indicated that the biomass in 2000 was above the biomass supporting the maximum sustainable yield (MSY). Overfishing: Unknown; Preliminary analyses of common thresher shark catch and effort in the pelagic drift gillnet fishery operating off the U.S. West Coast indicated that the catch-per-unit-effort of thresher sharks was increasing in the late 1990s above historical lows experienced during the early 1990s. Thus, in the U.S. West Coast EEZ, it was estimated that the local population of common thresher shark was not experiencing overfishing at that time, and the population may have been rebuilding.

09-01-2010, 10:46 AM	#3
dos ballenas Vampyroteuthis infernalis Join Date: Nov 2005 Posts: 585	check this out: http://www.bloodydecks.com/forums/ca...ase-first.html the current status of the population is unknown... but likely is at sustainable levels. But, like Black Seabass, threshers are susceptible to overfishing. Sharks are known to live for a long time. They are slow to grow, have very few babies, and don't reach reproductive maturity until about 4 years old. Harvesting young pups and large breeders are two things that could have a negative impact on their long term sustainability. Thresher sharks are also known as ram ventilators, which means they have to be swimming forward in order to breath. This is a problem because many times they get hooked in their tails. Threshers like to hit their prey with their tails to stun them. This results in tail hooking and during the fight, the sharks are dragged backwards through the water. As a result, many sharks are fought to the point of exhaustion, and when released, some do not survive. Many people feel that recreational sport fishing pressure on threshers has increased in recent years due to the sharing of current fishing reports on the internet, and the fact that thresher sharks are very easy to hook. The possible results from an increase in recreational fishing pressure have not been studied. The are no regulations on sharks fishing currently. That means you can keep as many as you want, of all shape and sizes. That doesn't mean that you should. There are many reasons why keeping threshers is controversial, and many reasons why some sort of regulation may be implemented. Most reasons are based on the biology and life history of the animal. __________________ ____________________________________________ Last edited by dos ballenas; 09-01-2010 at 01:00 PM.

09-01-2010, 12:46 PM	#6
dgax65 Guerro Grande Join Date: Jan 2006 Location: Houston, TX Posts: 629	I wouldn't mind seeing more restrictive limits on thresher and mako. The only problem is that more restrictive limits on recreational anglers are pretty much pointless when there is long-lining going on just outside of our waters. Commercial long liners probably take more in a day than the entire yearly recreational catch. Its too bad mako aren't cute like dolphin. If they were, the PETA/Greenpeace/Sea Shepard douchebags would be all over it. Stop buying shark, tuna, swordfish, rockfish....from the market and convince all your friends and acquaintances to do likewise and maybe we wouldn't have to reduce the recreational take limits. __________________ Douglas Gaxiola Team No Fish- Amateur Staff

09-01-2010, 05:29 AM	#2
FISHIONADO Senior Member Join Date: May 2006 Posts: 698	Maybe there is no debate on this subject? Someone mentioned in another thread that their friends were trying to get the DFG to change the rules on threshers. Anyone have the data they were using? I'm interested because I have released threshers in the past because I thought they were endangered based on the opinions on all the fishing forums. But my own quick research says they are at sustainable levels in Southern California. Is it just an emotional thing or is there current scientific data to support "no take"? This is the same reason I fought the MLPA so strongly, I want regulations based on science and not emotion. Peace all!

09-01-2010, 11:55 AM	#4
FISHIONADO Senior Member Join Date: May 2006 Posts: 698	Great input, thanks. Do you have any idea what the major threats are to threshers and where kayak fishing ranks? I've never targeted them, always figured I would take one if it was by-catch and drowned or was the right size for me to land alone.

09-01-2010, 12:16 PM	#5
CurtyL Senior Member Join Date: May 2009 Location: wherever the college girlz r Posts: 127	my take is pretty simple. If I'm not eating it I'm not keeping it. I don't like T so I don't keep them. I do try and get my hooks back though.

09-01-2010, 08:10 PM	#8
Ohana Senior Member Join Date: Oct 2009 Location: Coto de Caza, CA Posts: 155	FISHIONADO: Thanks for starting this topic. It is definitely something worth having a good discussion about. Having fished for Threshers for the last 10 years, I would say that the fishery from recreational fisherman pressure has increased due to the increase in number of boaters (especially in the middle of the last decade) and the relatively close inshore nature of the sharks has made them easy to target for a larger percentage of fisherman (no long travel using up expensive gas). I know that when I first started catch and release of T-sharks, you rarely heard about it on the local fishing boards, but as more people started posting the knowledge of this fishery, when was the optimum time to fish, techniques/locations, and the ease at catching them, it seemed like every spring everyone who had a boat was out trolling for T-sharks and were showing off their catch being weighed rather then releasing the sharks. Does this have an impact on the fishery? Hard to say as removal of certain numbers may actually improve the health of the population as there is less competition for food/ decreased cannibalization increasing the recruitment size. But considering that T-sharks give birth to living young, their litter size is small (2 to 4 pups), and that they take between 7 and 13 years to reach sexual maturity would make them more vulnerable to overfishing then other large gamefish, such as marlin, swordfish, and white seabass which produce large number of eggs and mature at a faster rate. As off the Southern California coast it appears to be the T-shark pupping grounds, both newborn, juvenile, and adult sharks can be caught year round, resulting on a potential overfishing impact to all populations of growth stages of the T-shark. Based on my observations the last 10 years and the fact that we humans lack certain levels of self control (i.e. how we got into the current economic mess ) ), I am for a limit on the number kept and setting the maximum size of 150 lbs that can be kept by recreational fisherman. I choose a maximum size as the idea is to increase survival of the breeding class and that a small/medium T-shark (<150 lbs) is plenty of good meat. Please note that I am strong believer that recreational fisherman are low on the scale of threats to saltwater fish populations; habitat destruction, pollution, and commercial gillnet/longline fishing are far and away the biggest threats. Thanks again for starting this topic and I look forward to reading other peoples responses. Kevin

09-02-2010, 06:00 AM	#9
FISHIONADO Senior Member Join Date: May 2006 Posts: 698	If anyone here supports slot limits maybe they could explain the benefit of releasing the smaller threshers. Is it because they are too easy to catch? Agree Kevin it's nice to see a civil discussion on this topic. I have a lightly supported opinion that threshers from SoCal are a sustainable resource based on the NOAA website, but I'll flip flop in light of compelling information. I always refuse shark fin soup during biz travel to Asia. And chicken feet....