2016 Striped Bass Stocking

[mwardncsu]

Below are the tallys of the 2016 Stocking. Ken Ulrich, Operations Chair in the Smith Mountain Striper Club, oversaw the stocking at several drop-offs this year. The process was a bit different in 2016 than in past year - previously there were two, maybe three trips to the lake in which stripers were stocked in multiple locations per trip. However, the new hatchery manager in place at Vic Thomas Hatchery desired to make more frequent runs to one, or a smaller number of, locations - with less fish on the truck at a time to help maximize the health of the fish.

We received fish from Brookneal/Vic Thomas and also from King & Queen hatcheries this year. These fish were all "Roanoke strain" as I understand it (last year we stocked with Bay resident fish in an attempt to determine if there is any genetics issue playing into our lower than average growth rates).  Part way through the stocking I received word that it was uncertain if we would receive our target of 300K due to poor yields from the grow-out ponds this year - in years with a lot of rain / cloud cover there often is not enough algae production to provide the food needed for the fry - which leads to poor yields.   However, DGIF was able to juggle some things, cut out some smaller stockings at some secondary priority lakes and redirect some fish from King & Queen hatchery to Smith Mountain Lake. In all we received around 317 thousand stripers form 1" - 1.5". Sounds like a lot, but remember there is a VERY high mortality in the 1st year. Target stocking has been around 300K the last number of years. Some years back we received 400-450K, but there was a concern that the striper population was too large for the available forage base and risked potential of another crash, so it was reduced to the 300-350K/year range.

Stocking totals across sites are below - there were some additional above plan stocked in the upper Roanoke due to the forage base that was measured by DGIF when doing bait sampling.

Date	Site	# Released	Avg Size (in)	Avg # / lb	Hatchery	Roanoke	Blackwater
6/11 & 6/30	Penhook	37,743	1.0	1,718 & 2,535	VT & KQ		37,743
6/14	Scruggs	31.240	1.5	1,562	VTFCS		31,240
6/30	Rt 655	35,744	1.0	2,535	VTFCS		35,744
6/30	Our Place Marina (Craddock Creek)	35,490	1.0	2,535	KQFCS	35,490
6/14	Anthony Ford	31,240	1.5	1,562	KQFCS	31,240
6/25	State Park	30,915	1.5	1,718	VTFCS	30,915
6/25	Hales Ford Bridge	30,915	1.5	1,718	VTFCS	30,915
6/16 & 6/27	Indian Point	27,643	1.5	1,562	VTFCS	27,643
6/29	Pleasure Point	25,098	1.4	2,024	VTFCS	25,098
6/16	Moormans	31,240	1.5	1,562	VTFCS	31,240
Totals		317,268	1.3	1864.22		212,541	104,727

[mwardncsu]

And before the Blackwater guys complain about not getting enough fish - don't forget that Anthony Ford is almost more BW than Roanoke - and all the Craddock Creek stocked fish run up the Blackwater anyway.....

[BentRod]

Anthony ford is on the Roanoke - how's it more Blackwater than Roanoke? You sound like a politician.

[drag4striper]

Have there been any studies or estimates showing the survival of the stockings to catchable size? Say maybe 8 to 10% or more?

[mwardncsu]

Jul 6, 2016 15:49:01 GMT -5 BentRod said:

Anthony ford is on the Roanoke - how's it more Blackwater than Roanoke? You sound like a politician.

It's down there close to the mountain, yes technically on the Roanoke but we all know that all the fish near the dam run up the Blackwater and don't come up past the State Park.....

[mwardncsu]

Jul 6, 2016 15:53:09 GMT -5 drag4striper said:

Have there been any studies or estimates showing the survival of the stockings to catchable size? Say maybe 8 to 10% or more?

I'l have to dig up some old data from Dan Wilson - don't have it on my current laptop.... I think Year 1 mortality is estimated at 70% - but then Year 2 mortality flips to 10% (fish are apex predator at that point but too small for anglers) and then an added 20% of angler impact, for a total of estimated at 30% mortality for Year 3 and on . I may be off on those numbers but its roughly what I remember - probably can find it somewhere on an older post here about stocking or other related topic.

Using those percentages - here is what 317K fish from the Class of 2016 become over 15 years.....

Age	Mortality	# Fish
Year 0		317,000
Year 1	70%	95,100
Year 2	10%	85,590
Year 3	30%	59,913
Year 4	30%	41,939
Year 5	30%	29,357
Year 6	30%	20,550
Year 7	30%	14,385
Year 8	30%	10,070
Year 9	30%	7,049
Year 10	30%	4,934
Year 11	30%	3,454
Year 12	30%	2,418
Year 13	30%	1,692
Year 14	30%	1,185
Year 15	30%	829

Of course that is an estimate - and any given year can be different - the 1st year is obviously the most critical until the fish grow large enough to be safe from other predators.   Gill Netting done each year helps to provide some estimate of the stocking success of previous years - the smallest stripers the nets get are the 18 month olds - and usually up to 3 or 4 years.

The above is of course additive year on year with each year's stocking.   A couple of years ago I tried to build a model using the above assumptions and assuming we had no fish post fish-kill (which of course was not accurate) - and then laying in the stocking rates for each of the years since - and some adjustment for the "success" of each year's stocking based on gill-net results - just to try and get a feel for how many fish would theoretically be in the lake - and across what age classes.

Based on that info - I'm increasingly wondering if the 20% angler impact is under scoped....  my guess is we don't have 20% impact on the Age 3-4, but its probably a fair bit more than 20% on age 5+ - again, I don't have any hard data on this but you have to keep a WHOLE lot more 3-4 year old fish to have a 20% impact than you do on a 10 or 15 year old fish....  I'd say the model needs to be adjusted for increased angler impact rates in the older fish.

[drag4striper]

Thanks for the interesting information, I had always wondered about the survival rate of stocked stripers. 

The young fish really take a big hit in the first year as I expected. I wonder if DGIF could increase the survival 

rate by letting the stripers get larger before they are stocked?

[striperjohn]

I think I recall them saying if you keep them in pen feeding too long they can't survive in the wild in their own.

[coheasion]

Sobering information as it pertains to catch and release. A striper growth chart I found online shows that on average a fish needs to reach 15+ years of age to reach 40 lbs. We aren't allowing many fish to get into that range if only 829 of 300k possibly survive that long.

Cue up the recent Catch and Release works post again.

[drag4striper]

Jul 7, 2016 6:50:16 GMT -5 striperjohn said:

I think I recall them saying if you keep them in pen feeding too long they can't survive in the wild in their own.

I have an idea. If the DGIF could install some floating pens inside the boom at the dam. They could then let the stocked fish get larger before

they release them. And I would think swimming in the current the dam produces would make them healthier than just be raised in a pond or pool.

Just thinking out loud.

[mwardncsu]

John is right - there is a trade-off in size at which they become a bit too "domesticated" if you will and have more issues adapting to the natural available "forage" (algae/plantkon, then bugs, then other live stuff). That said TN has historically grown theirs out a bit larger before stocking (though they stock less). But let's be honest - in addition to what is optimal for their acclimating and adapting to the new environment - this is largely an also an issue of resources (the larger the fish the less can go in each grow-out pond, so it means more ponds are needed), more $$$$, additional handling of fish from one pond to another for larger size - etc.

Would a set of large grow-out nets floating in a protected area work? Interesting though - my guess is that environment is actually not ideal in terms of forage but honestly don't know. Then there is logistics of accessing the pens, re-harvesting to then go and redistribute, etc. However, these are good thoughts and the types of discussions we like to encourage with DGIF on continual improvement to the methods used.