Nass Update to July 11th, 2010

Here is the Nass Update to July 11th, 2010. Information provided courtesy of Nisga'a Fisheries.


2010 NASS RIVER STOCK ASSESSMENT UPDATE – SUNDAY 11 JULY 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 (AND MEZIADIN FISHWAY) OPERATIONAL NOTES:

Fishwheel (and Meziadin Fishway) assessment data: Up to Saturday 10 July 2010

Meziadin Fishway began operations on 28 June. Counts of adult sockeye (6,928 vs. 6,200) and Chinook (9 vs. 4 94-09 mean) are just above average (94-09) to date. Other counts are: 72 tagged sockeye, and 8 sockeye jacks (<45 cm).

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 on 1 June for applying additional Chinook tags as part of the Nass Chinook Sentinel Stock Program and will only operate in June and a portion of July once the majority of Chinook have passed GW. All fish caught at the GW fishwheels will be released in 2010. Daily catches of salmon at the Gitwinksihlkw fishwheels have picked up for sockeye (averaging ~175 per day) and dropped for Chinook (averaging ~3 per day) over the past five days.

Fishwheels 1 and 2 are currently operating at near ideal catchability water levels but below average water to date (2.5 m vs. 3.0 m average (94-09)).

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

Three fishwheels (FW#3, 5 and 6) are operating at Grease Harbour (upstream of Ts'im Anwiihlist) for in-season mark-recapture tag recoveries and for some selective harvesting of sockeye, Chinook and/or coho salmon to begin in July and/or August 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) and 7 June (FW#3 and FW#6).

Selective harvesting of sockeye at the Grease Harbour fishwheels began on 5 July. Harvests to date are: 2,526 sockeye. A small sample of Chinook (111 to date) have also been harvested at the Grease Harbour fishwheels for morphometric length research as part of the Nass Chinook Sentinel Stock Program. The Chinook that have been harvested have been distributed to the elders and community food programs. Daily catches of salmon at the Grease Harbour fishwheels have picked up for sockeye (averaging ~475 per day) and dropped for Chinook (averaging ~15 per day) over the past five days.
NASS SUMMER-RUN STEELHEAD:

Total catch of steelhead at the Nass fishwheels to date is 16. The GW catch (11 vs. 6) of steelhead is above average based on mean catches from 1994-2009 to week ending 10 July. No steelhead have been caught since 24 June.

In-season run size estimates that will be 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. These estimates will begin in mid-July.

The Nisga’a catch of steelhead to week ending 3 July is 302 and includes spring run steelhead caught in May and June. The average harvest of Nass steelhead in the Nisga’a fishery is ~400 from 1994 to 2009 catch monitoring programs. A total of 139 steelhead have been released in the Area 3 gillnet fishery in 2010.


NASS SOCKEYE SALMON:

Total catch of sockeye at the Nass fishwheels to date is 7,238 adults (2,618 tagged) and 828 jacks. The GW catch (3,095 vs. 6,800) of adult sockeye is currently below average based on mean catches from 1994-2009 to week ending 10 July. The GW catch (582 vs. 280) of jack sockeye is currently above average.

The recommended run size target for adult Nass sockeye to Gitwinksihlkw is 275,000. 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 10 July (91,213) is currently tracking below average (108,000) 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 5 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 10 July is 260,000 (95% CI: 130,500, 390,000) based on in-season to post-season 93-09 linear regression relationship (r2=0.66). Using the 94-09 mean-run timing method, the projection is 237,000 (+/- 2 S.D: 156,000, 492,000). A chart is attached to show the daily projections since mark-recapture estimates started on 28 June.

Using the 93-09 median run timing to GW fishwheels (37%), in-season net escapement (~86,000) and total Canadian catch (~76,000) estimates to 10 July, the TRTC estimate for Nass sockeye is 451,000.

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 ~71,000 sockeye to date based on the in-season TRTC estimate.

Nisga’a FSC fisheries continue with current catch monitoring results up to 3 July. Catch results up to 10 July will be available on Wednesday, 14 July. Total FSC catches to date are: 6,954 sockeye, 3,386 Chinook, 1 coho, 13 pink, 11 chum and 302 steelhead. FSC catches to week ending 3 July are currently average for sockeye (6,954 vs. 7,100) and for Chinook (3,386 vs. 3,200) based on mean catch monitoring results from 2000 to 2009.

Three Nisga’a marine fisheries in Area 3-12 have occurred to date on 2 July (29 boats), 9 July (29 boats) and 10 July (21 boats). Total marine catches to date are: 8,595 sockeye, 30 Chinook, 5 coho, and 273 pink. A 10-hr (8:00-18:00 hrs) Nisga’a in-river sale fishery has been announced for Monday, 12 July. A closure above Grease Harbour at the entrance of the canyon near fishwheel 3 will be in effect for this fishery to limit by-catch of Chinook. Nisga’a Fisheries will make an announcement on Tuesday (13 July) regarding the next planned individual sale fishery openings in marine or in-river. Total estimates of Nisga’a catch to date are: 18,705 sockeye, 3,527 Chinook, 6 coho, 286 pink, 11 chum and 302 steelhead.

Area 3 commercial fisheries conducted in 2010 to date: 6 gillnet [15 June (150 boats), 21 June (164 boats), 28 June (216 boats), 29 June (216 boats), 5 July (228 boats) and 6 July (228 boats)]. Total in-season commercial harvest estimates in Area 3 to date are: 53,877 sockeye; 0 coho (1744 released); 5365 pink (39 released); 15,388 chum (2097 released) and 692 Chinook (246 released). The next Area 3 gillnet fishery has been announced by DFO for Monday 12 July for both seines and gillnets. Non-retention of chum, Chinook, coho and steelhead in Area 3 will be in effect. An opening in Area 4 for gillnet was also announced for Monday, 12 July. Source of commercial information is courtesy of DFO Prince Rupert Fisheries Management.

Alaskan gillnet fisheries in Districts 101 (Tree Point) and 106 (Sumner and Upper Clarence) began on 20 June and 21 June, respectively. District 101 (Revilla & Lower Clarence) and District 102 (Middle Clarence) Alaskan seine fishery began on 4 July and 21 June, respectively. Total gillnet catches at Tree Point to date are approximately: 36,500 sockeye, 1,280 Chinook, 3,900 coho, 26,150 pink and 124,000 chum salmon. Tree point catches are average for Chinook (~1200) and coho (~4100), below average for sockeye (~50,000) and pink (~60,000); and above average for chum (~65,000) to date. Total catches in all districts to date are approximately: 82,500 sockeye, 2,300 Chinook, 68,250 coho, 106,500 pink and 295,000 chum salmon. Source of Alaskan commercial 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 945 adults (323 tagged) and 415 jacks. The GW catch (296 vs. 1,550) of adult Chinook is below average based on mean catches from 1994-2009 to week ending 10 July. The GW catch (147 vs. 120) 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 10 July (7,548) is tracking below average (20,000) 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 11 July is 10,000 (95% CI: 6,000, 14,000) based on in-season to post-season 93-09 linear regression relationship (r2=0.95). Using the 94-09 median run timing to GW fishwheels (86%), in-season net escapement (7,105– coastal and in-river estimate) and total Canadian catch (6,676) estimates to 10 July, the TRTC estimate for Nass Chinook is 16,000. Pre-season TRTC forecasts range between 29,000 (minimum brood estimate) and 44,000 (maximum brood estimate). Based on the pre-season TRTC forecasts and the minimum escapement goal (10,000), the Nisga’a allocation of Nass Chinook ranges between 6,000 and 9,500 plus an underage (up to 4,500) to account for management uncertainty allowances as part of the overage/underage calculations from 2000 to 2009. The in-season target is estimated at ~3,400 Chinook (plus underage allowance) to date based on the in-season TRTC estimate.

The total Nisga’a harvest estimate of Nass Chinook to date is 3,527. FSC catches to week ending 3 July are about average for Chinook (3,321 vs. 3,200) based on mean catch monitoring results from 2000 to 2009. Nisga’a FSC harvest of Chinook is anticipated to reach between 5,000 and 7,000 in 2010.

Area 3 commercial gillnet harvest of Chinook to date is 692 (246 released). No estimates of the Nass component are currently available to Nisga’a Fisheries. The total in-season harvest estimate of Chinook in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~2,500.

NASS COHO SALMON:

No coho salmon have been caught at the Nass fishwheels to date. Coho typically begin to be caught at the fishwheels in mid-July.

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.

The total Nisga’a harvest estimate of Nass coho salmon to date is 6. FSC catches to week ending 3 July are just about average for coho (6 vs. 9) based on mean catch monitoring results from 2000 to 2009.

Area 3 commercial gillnet harvest of coho salmon to date is 0 (1,744 released). The total in-season harvest estimate of coho in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~68,000.

NASS PINK SALMON:

Total catch of pink salmon at the Nass fishwheels to date is 7. The GW catch (4 vs. 6) of pink is about average based on mean catches for even years from 1994-2009 to week ending 10 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. The mean brood pre-season TRTC estimate (149,000) will be used for calculating the initial target for the in-season Nisga’a allocation (<500). This target will be adjusted during the season based on in-season data. No cumulated overages or underages exist from 2000 to 2009.

The total Nisga’a harvest estimate of Nass pink salmon to date is 286. FSC catches to week ending 3 July are just about average for pink (286 vs. 300) based on mean catch monitoring results from 2000 to 2009 for even year catches.

Area 3 commercial gillnet harvest of pink salmon to date is 5,365 (39 released). The total in-season harvest estimate of pink salmon in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~107,000.

NASS CHUM SALMON:

Total catch of chum salmon at the Nass fishwheels to date is 2. The GW catch (1 vs. 1) of chum is average based on mean catches from 1994-2009 to week ending 10 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 mean brood pre-season TRTC estimate (61,000) will be used for calculating the initial target for the in-season Nisga’a allocation (5,000). This target will be adjusted during the season based on in-season data. The actual allocation target may be up to 36,000 more to account for overage/underage allowances from 2000 to 2009. However, underages would only be targeted in productive return years as assessed during the season, and opportunities of utilizing the underage for Nass Area chum are not anticipated for 2010.

The total Nisga’a harvest estimate of Nass chum salmon to date is 11. FSC catches to week ending 3 July are below average for chum (11 vs. 70) based on mean catch monitoring results from 2000 to 2009 catches.

Area 3 commercial gillnet harvest of chum salmon to date is 15,388 (2,097 released). The total in-season harvest estimate of chum salmon in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~294,500.

Escapement updates will be available at the above website link on Tuesday, 13 July and Thursday, 15 July.

The next Nass River public stock assessment update is planned for: Sunday, 18 July.