Summary Of Gillnet Sizes Used For Lake Sturgeon

 

Based on an e-mail survey of researchers

by

 Thomas E. Brooking

 

Cornell University Biological Field Station

900 Shackelton Point Rd.

Bridgeport, NY 13030

(315) 633-9243

 9/13/2000

 

 

During the summer of 2000, I conducted an e-mail survey of various researchers working on sturgeon, especially lake sturgeon. Researchers were asked to provide information on what size and type of nets they used for capturing both juvenile and adult sturgeon, and provide any insightful comments that may be helpful when purchasing new nets. Based on the information below, we chose to purchase monofilament gillnets of the following size for sub-adult and adult lake sturgeon: mono, 88 m long, with 8 panels each 11m long, of the following mesh sizes: 6, 8, 10, 12, 6, 8, 10, 12”. These nets have proven to be very effective for sturgeon from 900-1200 mm.

 

 

 

Nets for small fish

Nets for adult fish

Researcher

Size

Type

Size

Type

 

S. Schram – WI DNR

C. Mackenzie – VT F&W

T. Chiotti – NY DEC

J. Hayes – SUNY ESF

H. Quinlan – USFWS

C. Lowie – USFWS

D. Noakes – U. of Guelph

T. Hill – USFWS

A. Runstrom – USFWS

S. Schlueter – SUNY ESF

R. Colombo – Shedd Aqu.

M. Bain – Cornell Univ.

R. Fortin – Univ. Quebec

L. Mohr – OMNR

D. Peterson – Central MI Univ.

E. Baker – MI DNR

L. Meyers – WI DNR

G. Kornely – WI DNR

T. Brooking – Cornell Univ.

T. Heinrich – MN

G. Whelan – MI DNR

 

1.5-7”

--

1-5.5”

2-4.5”

--

1-6”

--

--

2.5-6”

--

2, 4, 6”

--

4.5-5.5”

--

--

--

--

1.5-4”

--

graded mesh

 

mono

--

--

mono

multi

--

mono, multi

--

--

mono

--

mono

--

mono

--

--

--

--

multi

--

--

 

8, 10, 12, 14”

8, 10, 12”

--

8, 10, 12”

8-12”

10”

--

8, 10”

8, 10, 12”

7, 8, 10”

8, 10, 12”

14”

8, 9, 10”

9, 10, 12”

8, 10, 12”

8, 10”

7.5-8”

10”

6, 8, 10, 12”

8, 10, 12”

8, 10, 12”

 

 

mono

multi, mono

--

mono

mono, multi

mono

--

mono

mono, multi

mono

mono

multi

mono

multi, mono

mono

mono

multi

multi

multi

--

--

 

 

 

 

Comments from individual researchers are listed below:

 

 

Our gill net specifications for sturgeon vary by assessment. We sample sturgeon during our spring lake trout survey using 4 1/2"  stretch multifilament nylon nets. During the summer we fish mono from 1 1/2" up to 7" stretch by 1/2" intervals. The nets are designed to catch all species including sturgeon. I can provide more details if desired. We "target" sturgeon in Chequamegon Bay using 8", 10", 12" and 14" stretch monofilament nets.

 

Mesh

Twine size

Meshes deep

No. 8 mono .47mm

13

10”

No. 8 mono .47mm

11

12”

No. 16 mono .66mm

12

14”

.74mm

7

 

 

These nets are set overnight. We have been using them for 13 years, have caught and released 20-60 fish per year and have never killed a single fish. Hope this helps. Please let me know if you need more information.

 

Stephen T. Schram

Wisconsin DNR

____

 

Donna Parrish forwarded your message about gillnet sizes to me a couple of weeks ago. Sorry for the delay. In Vermont, we've been using 8", 10", & 12" stretched mesh multifilament gillnets to capture spawning lake sturgeon.   Sizes were recommended to us by Rejean Fortin, University of Quebec, Montreal. Although a review of my notes indicates that he prefers monofilament. Also spoke to Micah Kieffer who preferred multifilament because he felt mono cut fish easier. Someone from this office also spoke to Doug Peterson and he preferred to use mono. We went with multifilament because we didn't want to cut fish and felt it would be easier to work with. Visibility is not great in the spring when we're surveying tribs to Champlain. In this years budget request I included money to buy both mono and multifilament nets to use next spring.

 

I've ordered twine size #208 in the past from Nylon Net Company. Sturgeon have not torn them up but the river has, particularly this year.

Hope this helps.

 

Chet Mackenzie

VT Fish and Wildlife

____

 

We have not yet had to capture fish large enough to require that we go larger than our largest mesh size-- 5 inch stretch.

 

Tom Chiotti

NYS DEC

____

 

During the course of my study I have handled fish from 195mm to 1800mm and have likewise used a variety of net sizes to do so. For juveniles up to 700 to 800 mm I have used experimental monofilament nets with 6 panels increasing from 1" to 5.5" stretch mesh.  For smaller adult sturgeon (excluding large females etc.) you may be able to get away with a 7" stretch mesh but I did have a couple of mortalities with this size with larger fish. I now use nothing smaller than an 8" mono with a tendency towards 10" and 12" during spawning runs.  If you have a large mature population that you are sampling you must be wary of the 7" net but otherwise you are probably ok. As far as multifilament ....never again. Twice was enough. I use mono with foam core float line vs floats and at least a 30 weight lead core line. Hope this helps. Any questions give me a shout.

 

Jennifer Hayes

SUNY ESF

____

 

In the draft lake sturgeon rehab plan for Lake Superior we outline the specs for assessment of lake sturgeon with gill nets. This is what is recommend.  For adults use 8-12" stretch measure gill nets of 0.47 to 0.66 mm monofilament twine at 11-13 meshes deep.

 

For juveniles the plan calls for 2-4.5" stretch measure of 210/2 multifilament nylon at 18 meshes deep.  This is used in L. Superior not in the rivers.

 

We (fishery agencies working L. Superior) have found that the larger mesh sizes capture larger fish.  One agency did try 14" stretch mesh but returned to the 10-12".  There are also variations of twine type and diameter.  Here at Ashland we also use 8 and 10" multifilament twine (#277).  The mono is generally used in the clear waters of L. Superior while multifilament can be used in the rivers.

Hope this is helpful.

 

Regards,

Henry Quinlan

USFWS Ashland, WI

____

 

We're using mono, 10" stretch only.  We catch sizes from 30" to 63".  We're happy with our results of that size range.

 

Christopher Lowie

USFWS Amherst, NY

____

 

We have used both monofilament and multifilamnet gill nets, with a range of sizes (experimental gill nets) from 0.5 to 15 cm.....because we were primarily interested in the capture of smaller fish. All our nets took a beating from the fish and the sunken logs and rocks in our collecting sites. Both seemed to catch fish equally well.

 

David Noakes

Univ. of Guelph, Canada

____

 

Although we have not been successful at catching sturgeon we are using 8 and 10 stretch mesh monofilament nets.  Dr. Doug Peterson from Central Michigan University suggested that we purchase this size of nets.  He has been very successful with capturing fish in Lake Michigan using these size nets.  Others that I am aware of who are using gill nets are Lloyd Mohr with the Ontario Ministry of Natural Resources and Chris Lowie with the Lower Great Lakes Fish and Wildlife Service Fishery Resources Office.  Both of these individuals are on the sturgeon list that you requested this information from.  I would expect both of them to respond.  I think you know Chris anyway.  If you need contact numbers for them give me a call or check our sturgeon web page www.midwest.fws.gov/sturgeon. Hope this is valuable to you.

 

Tracy D. Hill

USFWS Alpena, MI

____

 

We have been gillnetting and tagging lake sturgeon on the Wisconsin, Chippewa and Wolf rivers in Wisconsin.  This spring we tagged 200 lake sturgeon in 5 days of netting on the Chippewa.  Fish measured 1077-1765mm total length and weighed 7-40 kg.    We used both  #177 mono and #208 multifilament of mesh size 4, 5, and 6" bar measure.  I don't think you need anything bigger.  On occasion we get fish breaking out of the mono filament, but I don't recall problems with the multifilament.  At one time I tried to purchase 7" bar and was told the mesh had to be special orderer from Japan and that it was quite expensive.   I  purchase our nets from H. Christianson Co. in Duluth MN.   Their phone is (218)724-5509 and they are very friendly to deal with. I hope this helps. I wouldn't mind seeing some data on mesh size and size of fish you are catching and also what type of habitat you are sampling.

 

Thanks,

Ann Runstrom

USFWS La Crosse, WI

____

 

As you have found gillnets from 2.5 inch to 6 inch stretch mesh work  extremely well for juveniles.  When trying to catch larger adults we have used 7 and 8 inch stretch mesh, with the downside being larger adults get stuck in the net in such a position to hold their gillcovers shut resulting in higher mortalities.  Not only have we found this but we were missing the very large fish (>5.5 feet).  Switching to 10 inch stretch mesh nets had advantages; mortality was reduced on large fish while catching the same size classes the 8 inch stretch mesh size seemed to target.  The problem arises here in the material, unless you go to an expensive custom net, the major net manufactures will only make nets with approximately 25 pound mono.  Having used both mono and multifilament gillnets I prefer mono nets.  Mono nets appear to have a higher catchability, may be a direct result from stretching more than mutlifilament nets thus entangling and holding fish better.  With that being said this stretching also appears to be gentler on captured fish reducing abrasions more so than fish captured in multi nets.  I know in Quebec they use heavy monofilament nets to capture very large sturgeon with mesh sizes of 12 inches and greater, while down on the Hudson I believe they used mutlifilament nets on Atlantics (Tom Hughes could verify).  I guess in a nutshell Tom, knowing the fish you will be working with I would stick with mono nets increasing with the size of the fish, 7 and 8 inch stretch mesh would be suitable until you feel you have fish that weigh over 35 pounds (roughly).  When the average targeted fish are over this weight larger nets may want to be considered.  Jennifer Hayes and Steve LaPan would be a great resource for information on this matter.  We have worked together with various combinations of nets/materials and may be able to offer more detailed information on size class Vs. mesh size. Any questions you can drop me a line.  Take care.

 

Scott Schlueter

US Army/ SUNY ESF

____

 

We used up to 12” stretch measure nets to capture adult sturgeon.  I found working with mono nets easier, do to the fact that repairing any holes was easier.  As for juveniles the variable size mesh works great.  We did have increased mortality and morbidity in 8” stretch net as opposed to the 10” mono nets.

 

Good hunting and tight lines.

Robert E. Colombo

John G Shedd Aquarium

____

 

We used different gill nets for adult Atlantic sturgeon (14"/twine) and small Atlantics and all shortnose sturgeon (<1 m TL).  The small sturgeon nets were a set of 3 single-mesh nets: 2", 4", and 6".  This covers the range of sturgeon from 100 to 1000 mm FL well.  Both our sturgeons were pretty sticky to the nets because of very sharp scutes in small fish.  Lake sturgeon may be different.  For very small sturgeon; yearlings (Ύ100 FL), we believe our 2" nets had reduced catch efficiency.  To correct for that, we tried 1" nets for a summer.  These 1" nets had very low catch rates even for small fish, they did not differ from 2: net catch in small fish numbers, and they were quickly clogged by the plant debris sloshing around the bottom of the river.  So we gave up on small meshes.  All nets were single mono nets. Overall, we feel the 2/4/6 3-net sets covered your size range well. This method was defined fairly early in our work after some testing  around with gear.  We stayed with the method because we felt is was as good as can be done, and it worked well enough for our aims.

 

Hope this helps,

Mark Bain

Cornell Univ.

____

 

We use 8", 9" and 10" stretched monofilament gillnets to catch lake sturgeon spawners at the Des Prairies River spawning grounds, near the DPR Power House.

 

Rιjean Fortin

Universitι du Quιbec ΰ Montrιal

____

 

I have had experience gillnetting sturgeon in Lake Huron using 2 different approaches.  The first is in low flow, non-spawning areas and the second is in moderate to high flow areas in spawning areas.

 

1. We (our assessment team and commercial fishermen) use 2 different types of nets in this situation.  The first is small mesh nets (4.5 to 5.5" monofilament) which are set "loose".  By loose, I mean set very loosely and generally in a zig-zag pattern.  This allows the fish to bag itself, reduces incidental species, and has produced many fish in the 800 to 1500 range. The second type of net is a large mesh (9"-12")multifilament net.  The 9"nets are sometimes referred to as carp nets.  These nets are set a bit more rigid than the small mesh, but again not extremely taut.  This net produces generally only fish greater than 1000mm.  Commercial fishermen also incidentally capture small lake sturgeon in 2.5 to 3" monofilament gear targeted at yellow perch.  These nets are set fairly tight in shoal or nearshore areas.  Sturgeon are almost always alive in all of the gear mentioned above.

 

2. In spawning areas, we generally restrict ourselves to large mesh monofilament nets.  This is due to the lower amount of strain on the nets. These nets do perform well in high flow areas and are generally set parallel to the current, close to back eddys, and sometimes in a gentle sweep shape which sometimes produces better results.

 

We used to fish multifilament nets, but due to problems in getting supplies, we have switched to monofilament.  There still are multifilament nets being used by the commercial industry, especially the larger 9", 10", and 12".

 

Hope this is of help.

Lloyd Mohr

OMNR Ontario, CA

____

 

The nets we use for adults are 8 and 10" stretch mesh, however we will likely use some 12" nets this year.  For juvies, I would recommend nets up to 8" stretch.  Larger net will catch small fish (scutes get tangled) but they are best for fish greater than 150 cm.  We typically use mono but multi works well also.  The choice here, depends primarily on your preference.  Mono is easier to keep clean, and possibly a bit more durable, while the multi is a bit easier to handle and is also better if you want to make lots of minor repairs.  We use mono and rehang our nets each year with fresh webbing. Either way, make sure you get nets constructed with foamcore float and ledcore lines.  Plastic floats and leads will cause horrific tangles in large mesh nets! For lake sturgeon, you can really get away with nets that are only 6 feet deep, but most of our nets are 8' just for the sake of sampling continuity. If you are worried about bycatch, it's probably best to stick with the 6 footers. 

 

As for net makers, we have bought much of our stuff from Memphis Net and Twine, but we have just ordered some new nets from a relatively new company that is supposedly much better.  The name of this company is Nichols Net Company (or something similar) and they are located in the Midwest (Illinois?).  I don't have their phone number at hand right now, but I can get it if you need it. Hope this helps and good luck!

 

Doug Peterson

Central Michigan Univ.

____

 

I have used gillnets for lake sturgeon for several years with good success on adults.  I have used monofilament gillnets, 8" and 10" stretch mesh, and have been able to catch and release adult and large juvenile lake sturgeon from a number of water bodies with no known mortality.  The mono nets work well although they are not the easiest to work with, mono nets are difficult to pack into gill net boxes because they don't lay down as nicely as nylon nets.  I have also used graded mesh nylon gillnets in attempts to catch small juvenile sturgeon but to date have not had any luck.  However, I don't think it is because the fish avoid the nets but more likely because I am fishing in waters with few lake sturgeon and I'm not fishing in the right habitat (if you know the habitats I should fish to catch small juveniles please let me know).

 

If you would like more info about adult captures with gillnets I published a paper in NAJFM in 1999, volume 19:1080-1088.  I would be happy to send you a reprint if you'd like.  In addition, Steve Schram, Wisconsin DNR has used gillnets to catch lake sturgeon in Lake Superior for several years so he may be able to help you (schras@dnr.state.wi.us). I'm not sure I'm in a position to recommend anything because I have only used mono nets.  The only thing I can say with certainty is that the mono nets work very well.

 

Edward A. Baker, Ph.D.

Michigan Department of Natural Resources

____

 

We used a combination of 7.5 and 8 - inch stretch mesh gill net to capture 872 lake sturgeon in the upper Winnebago system that averaged 970 mm in total length with 88% of the catch ranging between 762 and 1118 mm. The gillnet was multifilament which appeared to hold up better than monofilament.  We would have to do more looking to determine the twine size.

 

Lee S. Meyers

Wisconsin DNR

____

 

For the past few years we have been capturing lake sturgeon with gill nets at spawning time in the Menominee River. (Thus we are selecting for adult fish) Using 10 inch stretch mesh, with nylon twine, we captured 102 lake sturgeon ranging from 40 to 60 inches in length. The net is about 6 feet in depth and is set in shallow water 2 to 8 feet deep. We lift the net twice a day and have not harmed the fish, although they do become very entangled.  I've had better success with this nylon twine than with monofilament. I have used both.

 

Greg Kornely

Wisconsin DNR

____

 

I received your request for gill net info from Mike Hendrix here at the NE Fishery Center.  We have gill-netted mature and subadult sturgeon for the Hudson River and Del. River for a number of years.  We tried the multi filament nylon in a variety of mesh sizes from Memphis Net and Twine and found that it is not real durable when it comes to the rigors of tidal River sturgeon fishing.  Commercial fisherman Doug Bush  (Embought Bay Fish Co., 134 Embought Rd. , Catskill, NY) constructed some very good nets for us under contract .   He has good expertise in mesh sizes necessary for different sized sturgeon.  He has used monofilament netting on occasion too - sometimes for drift-netting.   If you contact him be sure to let him know I gave you his name.

 

Jerre Mohler

NE Fishery Center, Lamar, PA

____

 

We have used 8" and 10" stretch mesh for adult surveys and graded mesh nets for juveniles.  We also think it would be worthwhile to also use some 12" stretch mesh for adult surveys but have not tried that size yet. Hope this helps.

 

Gary E. Whelan

MI DNR Fisheries Division

____

 

The area I sample sturgeon is the Rainy River / Lake of the Woods system, on the Minnesota - Ontario border. Generally gill nets are extremely size selective for lake sturgeon. Mesh sizes I use range up to 12" (stretch measure) nets.  Mean total lengths of sturgeon sampled, by mesh size, are: 8" - 1,034 mm, 10" - 1,193 mm, and 12" - 1,259 mm.  Individuals up to 1,900 mm have been captured by anglers, but the largest sturgeon I have sampled is 1,668 mm. If you would like more information regarding my sampling I will try to help.

 

Tom Heinrich

Large Lake Specialist, MN