Nass Update to Aug.8th, 2010

Here is the latest Nass Update provided courtesy of the Nisga'a Fisheries Dept.


2010 NASS RIVER STOCK ASSESSMENT UPDATE – SUNDAY, 8 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 Saturday, 7 August 2010



Meziadin Fishway counts from 28 June to 7 August are: adult sockeye (59,973 vs. 85,500 mean) and Chinook (184 vs. 230 mean) are below average based on counts from 1994 to 2009. Other counts are: 1,391 tagged sockeye, 1,471 sockeye jacks (<45 cm NF length), 1 tagged Chinook and 28 Chinook jacks (<50 cm NF length).

Kwinageese weir counts from 9 July to 8 August are: 30 adult Chinook (0 tags), 0 adult sockeye and 0 adult coho. Other adult counts are: 7 bull trout, 2 rainbow and 3 mountain whitefish.

Seaskinnish weir counts (net upstream) from 17 July to 5 August are: 7 adult Chinook (0 tags), 9 Chinook jacks (<50 cm NF length), 2 adult sockeye (0 tags), 1 adult coho (0 tags), 1 coho jack, and 2 adult Pacific lamprey (0 tags). Two adult steelhead and one adult trout have been counted moving downstream of weir. Other video counts are: beavers, otters, juvenile salmon and trout, northern pike minnow, sucker, sculpin, whitefish and one small unidentified non-salmonid in the viewing box.

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) operated below Gitwinksihlkw from 1 June to 27 July for applying additional Chinook tags as part of the Nass Chinook Sentinel Stock Program. Fishwheels 1 and 2 are currently operating at average water levels (2.1 m vs. 2.0 m mean) when compared to operational years from 1994 to 2009.

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

Four fishwheels (FW#3, 5, 6 and now FW#4) are now operating at Grease Harbour (upstream of Ts'im Anwiihlist) for in-season mark-recapture tag recoveries, additional tagging (adult steelhead, chum and Pacific 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. Start-up dates of GH fishwheels were: 5 June (FW#5), 7 June (FW#3 and FW#6) and 5 August (FW#4).

Selective harvesting of sockeye and coho at the Grease Harbour fishwheels began on 5 July. Harvests to date are: 6,023 sockeye and 477 coho. Sockeye harvesting at the fishwheels was shutdown on 24 July with a reduction in TRTC and entitlement estimates for Nass sockeye. A small sample of Chinook (155) were also harvested at the Grease Harbour fishwheels for morphometric length and sex research as part of the Nass Chinook PSC Sentinel Stock Program. The sample of Chinook were distributed to the elders and community food programs.

NASS SOCKEYE SALMON:

Total catch of sockeye at the Nass fishwheels to date is 19,601 adults (5,479 tagged) and 2,212 jacks. The GW catch (6,500 vs. 13,500 mean) of adult sockeye is below average based on mean catches from 1994-2009 to week ending 7 August. The GW catch (833 vs. 830) of jack sockeye is average to date.

The recommended run size target for adult Nass sockeye to Gitwinksihlkw in 2010 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 7 August (178,000) is tracking below average (230,000) 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 2 August. Mark-recapture (and best estimates of current run size) will fluctuate over a five 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 223,000 (95% CI: 134,000, 312,000) based on in-season to post-season 93-09 linear regression relationship (r2=0.90). Using the 94-09 mean-run timing (83% to date) method, the projection is 214,000 (+/- 2 S.D: 177,000, 271,000). 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 to GW and projection estimates may be under estimated by 10,000-20,000 when comparing the in-season fishwheel mark rate at GW versus the current Meziadin mark rate using a 18 d lag and tag retention rate of 80% (i.e., 20 July – 113,000 (fishwheel) vs. 128,500 (Meziadin) estimate).

Using the 94-09 mean run timing to GW fishwheels (83%), in-season net escapement (~155,000) and total Canadian catch (~140,000) estimates to date, the in-season TRTC estimate being used by Nisga’a Fisheries for Nass sockeye is ~356,000 (Min/Max ranges: 318,000, 449,000). DFO’s Bayesian Total Nass sockeye run estimate using Alaskan Tree Point catch data to 5 August is 560,000 (95% C.I. = 330,000, 905,000). Assuming a harvest between 120,000 and 160,000 Nass sockeye in Alaskan fisheries in 2010, the TRTC point estimate would range between 400,000 and 440,000.

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. Based on the in-season TRTC estimate, the in-season Nisga’a share of Nass sockeye is estimated at ~53,000 (Min/Max ranges: 44,000, 75,000).

Nisga’a domestic (FSC) fisheries continue with current catch monitoring results up to 31 July. Catch results up to 7 August will be available on Wednesday, 11 August. FSC catches to week ending 31 July are currently above average for sockeye (24,823 vs. 20,000 mean), coho (282 vs. 165 mean) and steelhead (365 vs. 100 mean – note atypical high abundance of steelhead encountered in early spring months); and below average for Chinook (4,062 vs. 5,500 mean), pink (570 vs. 850 even year mean) and chum (57 vs. 350 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 due to the current TRTC and Nisga’a entitlement estimates.

Total in-season catch estimates in Nisga’a fisheries to date are: 60,080 sockeye, 4,247 Chinook, 809 coho, 1,897 pink, 57 chum and 365 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 31 July are: 2,182 adult sockeye (30 tags recaps), 66 adult Chinook (1 tag recovery) and 1 adult coho (0 tags).

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 well below average for sockeye (48,000 vs. 80,000 mean); about average for Chinook (1,325 vs. 1,375 mean) and coho (12,000 vs. 13,000 mean); and above average for pink (277,000 vs. 202,000 mean) and chum (276,000 vs. 159,000 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: 3,050 Chinook, 195,000 sockeye, 132,000 coho, 4,033,000 pink and 779,000 chum salmon. Of the total sockeye catch reported, approximately 54,000 (28%) 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 1,097 adults (351 tagged) and 661 jacks. The GW catch (322 vs. 1,700) of adult Chinook is below average based on mean catches from 1994-2009 to week ending 7 August. The GW catch (184 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 7 August (8,126) is well below average (22,570) 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 has been used to generate the majority of the daily run size estimates for Chinook in 2010. The run size projection for Upper Nass Chinook to GW to date is 9,000 (95% CI: 7,900, 9,300) 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 (98%), in-season net escapement (~7,500 – coastal and in-river estimate) and total Canadian catch (~7,000) estimates to date, the TRTC estimate for Nass Chinook is 14,400 (Min/Max ranges: 14,000, 15,000). Based on the in-season TRTC estimate, the in-season Nisga’a share of Nass Chinook is estimated at ~4,000 (Min/Max ranges: 4,500, 4,700). The actual allocation share may be up to ~4,000 more for management uncertainty allowances as part of the overage/underage calculations from 2000 to 2009. However, the management uncertainty underage amount was not targeted in 2010 due to the poor return.

The total Nisga’a harvest estimate of Nass Chinook to date is 4,247. FSC catches to week ending 31 July are below average for Chinook (4,062 vs. 5,500 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. DNA analyses of the troll catch indicated that Nass chinook made up 0.6% and 0.8% in the two early samples, and 0% in the third and fourth samples. Source of catch and DNA information from DFO Prince Rupert. The total in-season harvest estimate of Chinook in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~3,050.

NASS COHO SALMON:

Total catch of coho salmon at the Nass fishwheels to date is 2,329 (951 tagged) and 475 jacks. The GW catch (1,011 vs. 700 mean) of adult coho is above average based on mean catches from 1994-2009 to week ending 7 August. The GW catch (150 vs. 60) 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 7 August (32,000) is tracking above average (15,000) based on a mean run size to Gitwinksihlkw of 82,000 from 1994 to 2009. The run size estimate has now switched to mark-recapture estimates from historical catch index estimates with sufficient tag recoveries at the Grease Harbour fishwheels (n=18) to generate independent in-season mark-recapture estimates. Currently, run size estimates are final to 31 July. Mark-recapture (and best estimates of current run size) will fluctuate over an eight 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 adult coho to GW to date is 136,000 (95% CI: 63,000, 208,000) based on in-season to post-season 94-09 linear regression relationship (r2=0.62). Using the 94-09 mean-run timing (18% to date) method, the early projection with this method is 179,000 (+/- 2 S.D: 95,000, 358,000).

Using the 94-09 mean run timing to GW fishwheels (18%), in-season net escapement (~58,500 – coastal and in-river estimate) and total Canadian catch (~4,000) estimates to date, the very early in-season TRTC estimate being used by Nisga’a Fisheries for Nass coho is ~346,000 (Min/Max ranges: 170,000, 928,000). Based on the preliminary in-season TRTC estimate, the in-season Nisga’a share of Nass coho is estimated at ~19,200 (the maximum treaty amount with Min/Max ranges: 13,600, 19,200). The actual allocation share may be up to 8,000 more depending on run strength to account for management uncertainty allowances as part of the overage/underage calculations from 2000 to 2009. However, the management uncertainty underage amount would only be targeted in 2010 if the return is well above average.

The total Nisga’a harvest estimate of Nass coho to date is 809. FSC catches to week ending 31 July are above average for coho (282 vs. 165 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 ~132,000.

NASS PINK SALMON:

Total catch of adult pink salmon at the Nass fishwheels to date is 755. The GW catch (500 vs. 3,000 mean) of pink is well below average based on mean catches for even years from 1994-2009 to week ending 7 August.

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 1,897. FSC catches to week ending 31 July are below average for pink (570 vs. 850 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 ~4,033,000.

NASS CHUM SALMON:

Total catch of chum salmon at the Nass fishwheels to date is 25 (22 tagged). The GW catch (17 vs. 20 mean) of chum is about average based on mean catches from 1994-2009 to week ending 7 August.

Pre-season TRTC forecasts for Nass Area chums range between 19,000 (minimum brood estimate) and 108,000 (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 8,600. The actual allocation share 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 300 in 2010.

The total Nisga’a harvest estimate of Nass chum salmon to date is 57. FSC catches to week ending 31 July are below average for chum (57 vs. 350 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 ~779,000.

NASS SUMMER-RUN STEELHEAD:

Total catch of steelhead at the Nass fishwheels to date is 132 (123 anchor tagged). The GW catch (50 vs. 53 mean) of steelhead is average based on mean catches from 1994-2009 to week ending 7 August.

In-season run size estimates presented for adult 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 7 August (1,850) is just above average (1,700) 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 run size projection for Nass summer-run steelhead to GW to date is 9,000 (95% CI: 5,000, 14,000) based on in-season to post-season 94-09 linear regression relationship (r2=0.71). Using the 94-09 mean-run timing (18% to date) method, the early projection with this method is 10,000 (+/- 2 S.D: 6,000, 41,000).

The Nisga’a catch of steelhead to week ending 31 July is 365 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.

OTHER FISHWHEEL CAUGHT SPECIES:

Other catches of adult salmon and non-salmon species at the fishwheels to date include: 240 Pacific lamprey (223 tagged), 183 Dolly Varden, 161 whitefish, 85 cutthroat, 70 rainbows, 50 Northern pike minnow, 22 suckers, 10 Peamouth chubb, 7 spiny sculpins, 6 redside shiners, 2 surf smelt and 1 mouse.

An escapement update will be available at the above website link on Thursday, 12 August.

The next Nass River public stock assessment update from Nisga’a Fisheries is planned for: Sunday, 15 August.