Tuesday, August 03, 2010

Latest Nass Update to August 2nd

Here is the latest Nass Update to August 2nd. Information provided courtesy of Nisga'a Fisheries Department.
Weve taken the liberty of cutting/pasting the steelhead section up to near the top for covenience.

2010 NASS RIVER STOCK ASSESSMENT UPDATE – MONDAY, 2 AUGUST 2010

Attached is a public Nass River salmon stock assessment update for 2010 (pdf format) from the Nisga’a Fisheries and Wildlife Department of Nisga’a Lisims Government. Sayt K'il'im Goot – one heart, one path, one nation.

All data presented in this update are preliminary and subject to change with further assessment information that becomes available and should be interpreted cautiously for in-season assessment purposes only.

ESCAPEMENT UPDATES AND FISHERY ANNOUNCEMENTS FROM NISGA’A FISHERIES AND WILDLIFE DEPARTMENT ARE AVAILABLE AT THE FOLLOWING LINK:

ftp://ftp.lgl.com/Nass%20Stock%20Assessment%20Updates/

It is recommended to refresh link (F5) each time & copy files to your machine before opening.

NASS FISHWHEEL, MEZIADIN FISHWAY, KWINAGEESE & SEASKINNISH WEIR OPERATIONAL NOTES:

Assessment data for fishwheels and Meziadin Fishway: Up to Sunday, 1 August 2010

Meziadin Fishway counts from 28 June to 1 August are: adult sockeye (55,000 vs. 70,500) and Chinook (160 vs. 160) are below average for sockeye and average for Chinook based on counts from 1994 to 2009. Other counts are: 1,290 tagged sockeye, 1,163 sockeye jacks (<45 cm NF length), 1 tagged Chinook and 21 Chinook jacks (<50 cm NF length).

Kwinageese weir counts from 9 July to 1 August are: 13 adult Chinook (0 tags) and 0 adult sockeye. Other adult counts are: 6 bull trout and 1 rainbow.

Seaskinnish weir counts (net upstream) from 17 July to 1 August are: 5 adult Chinook (0 tags), 7 jack Chinook (<50 cm NF length), 0 coho, 2 adult rainbow, 2 adult Pacific lamprey (0 tags), 9 juvenile trout, 1 adult sockeye (0 tags) and 1 beaver.

GITWINKSIHLKW (GW) FISHWHEELS (TEST FISHERY - 17TH YEAR):

Fishwheels 1 and 2 were started on 1 June for tagging and historical catch index assessments for salmon and steelhead. A third fishwheel (FW#7) began operation below Gitwinksihlkw from 1 June to 27 July for applying additional Chinook tags as part of the Nass Chinook Sentinel Stock Program. All fish caught at the GW fishwheels in 2010 will be released. Over the past five days, daily catches of adult salmon at the Gitwinksihlkw fishwheels have dropped for sockeye (averaging ~105 per day), low for Chinook (averaging <2 per day), chum (averaging ~1 per day) and steelhead (averaging ~2 per day), and increasing for coho (averaging ~47 per day) and pink (averaging ~25 per day).

Fishwheels 1 and 2 are currently operating at very low water levels (1.6 m vs. 2.1 m average (94-09)).

GREASE HARBOUR (GH) FISHWHEELS (~17 KM UPSTREAM OF TEST FISHERY):

Three fishwheels (FW#3, 5 and 6) are currently operating at Grease Harbour (upstream of Ts'im Anwiihlist) for in-season mark-recapture tag recoveries, tagging of adult steelhead, chum and lamprey; and for some selective harvesting of sockeye (ended on 24 July), Chinook (ended on 24 July) and coho salmon from July to September depending on run strength, Nisga’a entitlement levels and targets as directed by Nisga’a Lisims Government. FW#7 that was operating at GW up to 27 July will be moved to Grease Harbour this week for additional tag recovery, tagging, and harvesting of coho. Start-up dates of the GH fishwheels were: 5 June (FW#5) and 7 June (FW#3 and FW#6).

Selective harvesting of sockeye and coho at the Grease Harbour fishwheels began on 5 July. Harvests to date are: 6,023 sockeye and 23 coho. Sockeye harvesting at the fishwheels is now closed with a reduction in TRTC and entitlement estimates for Nass sockeye. A small sample of Chinook (155) were harvested at the Grease Harbour fishwheels for morphometric length research as part of the Nass Chinook Sentinel Stock Program. The sample of Chinook were distributed to the elders and community food programs. Over the past five days, daily catches of salmon at the Grease Harbour fishwheels have increased for sockeye (averaging ~400 per day), coho (averaging ~40 per day) and steelhead (averaging ~4 per day); steady for pink (averaging ~9 per day), and low for Chinook (averaging ~2 per day) and chum (averaging <1 per day).

NASS SUMMER-RUN STEELHEAD:

Total catch of steelhead at the Nass fishwheels to date is 73 (64 anchor tagged). The GW catch (33 vs. 25 mean) of steelhead is above average based on mean catches from 1994-2009 to week ending 31 July.

In-season run size estimates presented for Nass steelhead are only for summer runs (i.e., do not include any estimates for winter or spring run steelhead) and only cover return information from July to September when the fishwheels typically operate during summer run migration.

The Nass Summer-run steelhead in-season run size estimate to Gitwinksihlkw to 1 August (1,100) is above average (750) based on a mean run size to Gitwinksihlkw of 11,500 from 1994 to 2009. The run size estimate is using the same catch efficiency rates used for coho during the season. The early projected run size projection for summer-run steelhead to GW to date is 10,000 (95% CI: 4,500, 16,000) based on in-season to post-season estimates, 94-09 linear regression relationship (r2=0.50).

The Nisga’a catch of steelhead to week ending 24 July is 348 and includes spring run steelhead caught in May and June. The average harvest of Nass steelhead in the Nisga’a fishery is ~400 (range: 100 to 700) from 1993 to 2009 catch monitoring programs. Releases of steelhead in the Area 3 commercial fishery to date is 185 from gillnet and 11 from seine fisheries in 2010.


NASS SOCKEYE SALMON:

Total catch of sockeye at the Nass fishwheels to date is 16,633 adults (4,920 tagged) and 1,912 jacks. The GW catch (5,600 vs. 12,200 mean) of adult sockeye is below average based on mean catches from 1994-2009 to week ending 31 July. The GW catch (772 vs. 720) of jack sockeye is average to date.

The recommended run size target for adult Nass sockeye to Gitwinksihlkw is 275,000 depending on harvests projected above Gitwinksihlkw. The run size target has been set to have a greater certainty of reaching the Meziadin River escapement goal (160,000) which has represented 51% to 85% (avg. is 68%) of the total Nass sockeye aggregate population since 1994. The net aggregate escapement target is ~200,000.

The Nass sockeye in-season run size estimate to Gitwinksihlkw to 1 August (158,000) is tracking below average (205,000) based on a mean run size to Gitwinksihlkw of 278,000 from 1994 to 2009. The run size estimate is a combination of mark-recapture and historical catch indices methods. Currently, run size estimates are final to 27 July. Mark-recapture (and best estimates of current run size) will fluctuate over a 5 day period as additional catch and tag recovery data from the weekly GW tagging period pass the GH fishwheels. A spreadsheet of the calculations and range of estimates is provided in the attachment.

The run size projection for Nass sockeye to GW to date is 228,000 (95% CI: 142,000, 314,000) based on in-season to post-season 93-09 linear regression relationship (r2=0.89). Using the 94-09 mean-run timing method, the projection is 215,000 (+/- 2 S.D: 175,000, 278,000). A chart is attached to show the daily projections since mark-recapture estimates started on 28 June. Note that the current in-season run size and projection estimate may be 10,000-20,000 higher after comparing the in-season fishwheel mark rate versus the current Meziadin mark rate, using a 18 d lag and tag retention rate of 80%.

Using the 93-09 mean run timing to GW fishwheels (74%), in-season net escapement (~137,000) and total Canadian catch (~136,000) estimates to date, the TRTC estimate being used by Nisga’a Fisheries for Nass sockeye is 370,000 (Min/Max ranges: 314,000, 458,000). DFO’s Bayesian Total Nass sockeye return estimate using Alaskan Tree Point catch data to 29 July is 550,000 (95% C.I. = 380,000, 796,000). Assuming a harvest between 120,000 and 160,000 Nass sockeye in Alaskan fisheries in 2010, the TRTC point estimate would range between 390,000 and 430,000.

Based on the pre-season TRTC forecasts and the minimum escapement goal (100,000), the Nisga’a pre-season allocation for Nass sockeye ranges between 52,000 and 118,000. The pre-season target was ~113,000 based on the sibling forecast method. The in-season target is estimated at ~53,000 sockeye to date based on the in-season TRTC estimate.

Nisga’a domestic (FSC) fisheries continue with current catch monitoring results up to 24 July. Catch results up to 31 July will be available on Wednesday, 4 August. FSC catches to week ending 24 July are currently above average for sockeye (20,104 vs. 16,000 mean), coho (112 vs. 65 mean) and steelhead (348 vs. 80 mean – note atypical high abundance of steelhead encountered in early spring months); and below average for Chinook (4,090 vs. 5,400 mean), pink (402 vs. 615 even year mean) and chum (48 vs. 300 mean) based on mean catch monitoring results from 2000 to 2009.

Four Nisga’a marine sale fisheries in Area 3-12 have occurred to date on 2 July (29 boats), 9 July (29 boats), 10 July (21 boats) and 17 July (28 GN and 1 SN). Total marine sale catches to date are: 11,306 sockeye, 30 Chinook, 9 coho, and 1,327 pink. Four Nisga’a in-river sale fisheries have occurred to date on 12 July, 14 July, 16 July and 22 July. Total in-river sale catches to date are: 17,928 sockeye and 41 coho. Results of each fishery are provided in the attachment (pg 2 summary).

All Nisga’a sockeye sale fisheries are shutdown until further notice due to the current TRTC and Nisga’a entitlement estimates.

Total in-season catch estimates in Nisga’a fisheries to date are: 55,361 sockeye, 4,212 Chinook, 185 coho, 1,729 pink, 48 chum and 348 steelhead.

Area 3 commercial fisheries conducted in 2010 to date: Nine gillnet [15 June (150 boats), 21 June (164 boats), 28 June (216 boats), 29 June (216 boats), 5 July (228 boats), 6 July (228 boats), 12 July (56 boats), 13 July (107 boats) and 26 July (17 boats)] and three seine [12 July (9 boats), 13 July (9 boats) and 26 July (9 boats)]. Total in-season commercial harvest estimates in Area 3 to date are: 67,757 sockeye; 0 coho (2,852 released); 53,370 pink (126 released); 15,388 chum (18,782 released) and 694 Chinook (520 released). Areas 3 and 4 are currently closed to sockeye fisheries due to low returns of both Nass and Skeena sockeye. Source of commercial information is courtesy of DFO Prince Rupert Fisheries Management. Gitanyow Nass salmon harvests as reported by the Gitanyow Fisheries Authority to week ending 24 July are: 1,535 adult sockeye (30 tags recaps) and 57 adult Chinook (1 tag recovery).

Alaskan gillnet fisheries in Districts 101 (Tree Point) and 106 (Sumner and Upper Clarence) began on 20 June and 21 June, respectively. Alaskan seine fisheries opening dates are: District 101 (Revilla & Lower Clarence) – 4 July; District 102 (Middle Clarence) – 21 June; District 103 (Cordova) – 25 July; and District 104 (Noyes and Dall) - 4 July. Total gillnet catches at Tree Point to date are below average for sockeye (43,000 vs. 72,000 mean) and coho (8,900 vs. 10,000 mean); average for Chinook (1,300 vs. 1,350 mean); and above average for pink (207,000 vs. 145,000 mean) and chum (272,000 vs. 145,000 mean) based on catch data from 2000 to 2009. The total salmon catch estimate to date in districts 101-104 by gillnet and seine are approximately: 3,000 Chinook, 158,000 sockeye, 109,000 coho, 1,431,000 pink and 708,000 chum salmon. Of the total sockeye catch reported, approximately 47,000 (30%) are estimated as Nass origin based on mean stock composition estimates from 1982 to 2007. Source of Alaskan commercial catch information is from the Alaskan Department of Fish and Game (ADFG) website.

NASS CHINOOK SALMON:

Total catch of Chinook salmon at the Nass fishwheels to date is 1,085 adults (348 tagged) and 643 jacks. The GW catch (316 vs. 1,700) of adult Chinook is below average based on mean catches from 1994-2009 to week ending 31 July. The GW catch (182 vs. 170) of jack Chinook is just above average.

The recommended in-season run size target for adult Nass Chinook to Gitwinksihlkw in 2010 is 17,000 depending on harvests projected above GW. The net escapement target is ~15,000.

The Nass Chinook in-season run size estimate to Gitwinksihlkw to 1 August (8,100) is well below average (22,400) based on a mean run size to Gitwinksihlkw of 23,000 from 1994 to 2009. The run size is estimated based on catch indices where the cumulative daily catch of Chinook at FW1 and FW2 is multiplied by a catchability expansion factors from 1994-2009 post-season results depending on daily water levels. Three catchability index ranges are shown in the attachment based on: 1) mean catchability (7.6%), 2) low water/low catchability (3.9%) and 3) high water/high catchability (12.6%). The low water-low catchability estimate is being used to generate the current run size estimates for Chinook. The run size projection for Upper Nass Chinook to GW to date is 9,000 (95% CI: 7,800, 9,600) based on in-season to post-season estimates, 94-09 linear regression relationship (r2=1.00).

Using the 94-09 mean run timing to GW fishwheels (97%), in-season net escapement (~7,300 – coastal and in-river estimate) and total Canadian catch (~7,000) estimates to date, the TRTC estimate for Nass Chinook is 14,700 (Min/Max ranges: 14,000, 15,000).

The total Nisga’a harvest estimate of Nass Chinook to date is 4,212. FSC catches to week ending 24 July are below average for Chinook (4,090 vs. 5,400 mean) based on mean catch monitoring results from 2000 to 2009.

Area 3 commercial net fishery harvests of Chinook to date is 694 (520 released). Areas 1 and 2 reported Chinook harvests in the recreational and troll fishery is 18,350 and 64,000, respectively. The total in-season harvest estimate of Chinook in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~3,000.

NASS COHO SALMON:

Total catch of coho salmon at the Nass fishwheels to date is 584 (282 tagged) and 217 jacks. The GW catch (259 vs. 200 mean) of adult coho is above average based on mean catches from 1994-2009 to week ending 31 July. The GW catch (16 vs. 9) of jack coho is above average.

The recommended in-season run size target for adult Nass coho to Gitwinksihlkw in 2010 is 65,000 depending on harvests projected above GW. The net escapement target to the Upper Nass is ~60,000.

The Nass coho in-season run size estimate to Gitwinksihlkw to 1 August (11,400) is currently tracking above average (4,600) based on a mean run size to Gitwinksihlkw of 82,000 from 1994 to 2009. However, caution is warranted with the current estimate as the run size estimate is currently a historical catch index estimate until enough tag recoveries (>12) at the Grease Harbour fishwheels occur to start generating an independent, more accurate, in-season mark-recapture estimate. Three catchability index ranges are shown in the attachment based on: 1) mean catchability (4.3%), 2) low water/low catchability (2.8%) and 3) high water/high catchability (6.5%). The low water-low catchability estimate is currently being used to generate the current run size estimates for Upper Nass coho as tag recoveries at GH are only one to date. The run size projection for Upper Nass coho to GW to date is 165,000 (95% CI: 65,000, 265,000) based on in-season to post-season estimates, 94-09 linear regression relationship (r2=0.58).

Pre-season TRTC forecasts for Nass coho range between 104,000 (minimum brood estimate) and 127,000 (maximum brood estimate). Based on the pre-season TRTC forecasts and the minimum escapement goal (40,000), the Nisga’a pre-season allocation ranges between 8,000 and 10,000 for Nass Area coho. The mean brood pre-season TRTC estimate (115,000) will be used for calculating the initial target for the in-season Nisga’a allocation (9,000). This target will be adjusted during the season based on in-season assessments. The actual allocation target may be up to 7,000 more to account for management uncertainty allowances as part of the overage/underage calculations from 2000 to 2009. Underages would only be targeted in a productive return year as assessed during the season. It is too early to project TRTC estimate for Nass coho based on <10% return to date (94-09 mean run timing).

The total Nisga’a harvest estimate of Nass coho to date is 185. FSC catches to week ending 24 July are average for coho (112 vs. 65 mean) based on mean catch monitoring results from 2000 to 2009.

Area 3 commercial net fishery harvests of coho to date is 0 (2,852 released). Areas 1 and 2 reported coho harvests in the recreational fishery is 9,205. The total in-season harvest estimate of coho in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~108,500.

NASS PINK SALMON:

Total catch of pink salmon at the Nass fishwheels to date is 376. The GW catch (183 vs. 1,375 mean) of pink is below average based on mean catches for even years from 1994-2009 to week ending 31 July.

Pre-season TRTC forecasts for Nass pinks range between 68,000 (minimum brood estimate) and 230,000 (maximum brood estimate) for even year, two year return average. Based on the pre-season TRTC forecasts and the minimum escapement goal (150,000), the Nisga’a allocation ranges between 0 and 2,000 for Nass Area pinks. No cumulated overages or underages exist from 2000 to 2009.

The total Nisga’a harvest estimate of Nass pink salmon to date is 1,729. FSC catches to week ending 24 July are below average for pink (402 vs. 615 even year mean) based on mean catch results from 2000 to 2009 catch monitoring program for even year returns.

Area 3 commercial net fishery harvests of pink salmon to date is 53,370 (126 released). Areas 1 and 2 recreational catch estimates to date for pinks is 755. The total in-season harvest estimate of pink salmon in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~1,431,000.

NASS CHUM SALMON:

Total catch of chum salmon at the Nass fishwheels to date is 25 (19 tagged). The GW catch (14 vs. 10 mean) of chum is above average based on mean catches from 1994-2009 to week ending 31 July.

Pre-season TRTC forecasts for Nass Area chums range between 19,000 (minimum brood estimate) and 107,000 (maximum brood estimate). Based on the pre-season TRTC forecasts and the minimum escapement goal (30,000), the Nisga’a allocation of Nass Area chums ranges between 0 and 8,500. The actual allocation target may be up to 36,000 more to account for overage/underage allowances from 2000 to 2009. However, Nass area chum will not be targeted in Nisga’a fisheries to promote rebuilding of stocks in Area 3 and assisting in addressing one of the conditions of the MSC certification recently awarded to the Nass sockeye fishery. Nisga’a FSC harvest of chum will be minimal and is anticipated to reach between 100 and 500 in 2010.

The total Nisga’a harvest estimate of Nass chum salmon to date is 48. FSC catches to week ending 24 July are below average for chum (48 vs. 300 mean) based on mean catch results from 2000 to 2009 catch monitoring program.

Area 3 commercial gillnet harvest of chum salmon to date is 15,388 (10,982 released). The Area 3 commercial seine fisheries released 7,800 chum to date. The total in-season harvest estimate of chum salmon in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~708,000.


OTHER FISHWHEEL CAUGHT SPECIES:

Other catches of adult salmon and non-salmon species at the fishwheels to date include: 210 Pacific lamprey (193 tagged), 155 whitefish, 149 Dolly Varden, 83 cutthroat, 60 rainbows, 45 Northern pike minnow, 20 suckers, 10 peamouth chubb, 7 spiny sculpins, 6 redside shiners, and 2 surf smelt.

An escapement update will be available at the above website link on Friday, 6 August.

The next Nass River public stock assessment update from Nisga’a Fisheries is planned for: Sunday, 8 August.

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