Wednesday, June 30, 2010

Nass Update #2 to June 25th, 2010

Here is the Nass Update #2 to June 25th. Information provided courtesy of the Nisga'a Fisheries

2010 NASS RIVER STOCK ASSESSMENT UPDATE – 25 JUNE 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 assessment data: Up to Thursday, 24 June 2010
Meziadin Fishway: Begins operation on approximately 1 July 2010

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

Fishwheels 1 and 2 began operation on 1 June for tagging and historical catch index assessments for salmon and steelhead.

Fishwheels 1 and 2 are currently operating at below average water levels to date (2.5 m vs. 3.1 m average (94-09)).

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 (with the exception of a small sample of adult Chinook (~150) that may be sacrificed for scientific research as part of the Nass Chinook Sentinel Stock Program).

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). No fish have been harvested to date.

NASS SUMMER-RUN STEELHEAD:

Total catch of steelhead at the Nass fishwheels to date is 16 adults. The GW catch (11) of adult steelhead is currently above average (5) based on mean catches from 1994-2009.

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 19 June is 299 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 monitoring programs.

NASS SOCKEYE SALMON:

Total catch of sockeye at the Nass fishwheels to date is 1,211 adults (794 tagged) and 138 jacks. The GW catch (872) of adult sockeye is below average (~1,500) based on mean catches from 1994-2009.

The Nass sockeye in-season run size estimate to Gitwinksihlkw to 24 June (25,590) is currently tracking below average (31,500) based on a mean run size to Gitwinksihlkw of 278,000 from 1994 to 2009. 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 in-season net escapement estimate for Nass sockeye to date is ~25,500. The net escapement target is ~200,000.

The in-season run size estimate to Gitwinksihlkw is calculated by either a mark-recapture or historical catch indices method. Currently, the run size is estimated based on catch indices where the cumulative daily catch of sockeye at FW1 and FW2 is multiplied by weekly historic catchability expansion factors from 1994-2009 results. This method is the historical catchability index method which will be used until mark-recapture estimates begin later in June when enough tag recaptures (>12) have been caught at the GH fishwheels to begin making reliable mark-recapture estimates. A spreadsheet of the calculations and range of in-season estimates under different fishwheel water level conditions is provided in the attachment.

It is too early to make any in-season forecasts of projected run size to GW or Total Return to Canada (TRTC) estimates for Nass sockeye. Pre-season TRTC forecasts range between 350,000 (minimum brood estimate) and 686,000 (maximum brood estimate).

Based on the pre-season TRTC forecasts and the minimum escapement goal (100,000), the Nisga’a pre-season allocation ranges between 52,000 and 118,000 sockeye. The sibling (age) TRTC pre-season method (648,000) has tracked well in the past and will be used by Nisga’a Fisheries for calculating the initial target for the in-season Nisga’a allocation (113,000). This target will be adjusted accordingly based on in-season data. The actual allocation target may be up to 2,000 less to account for the cumulative overages/underages accrued from 2000 to 2009.

Nisga’a food fish (FSC) harvesting is open for all salmon species and is anticipated to reach between 25,000 and 40,000 Nass sockeye in 2010. The total Nisga’a harvest estimate of Nass sockeye to week ending 19 June is 378. The current FSC catch (378) is below average (2,000) for the 19 June week ending period based on 1994-2009 catches. The next Nisga’a salmon catch estimate for week ending 26 June will be available on Wednesday, 30 June.

No Nisga’a marine or in-river individual sale fisheries for Nass sockeye have occurred to date. A public announcement by Nisga’a Fisheries was released on 22 June with notification that Nisga’a marine sale fisheries for sockeye and Chinook are planned in the first week of July in Area 3. An official notice of opening will be announced 48 hours prior to the fishery opening.

Area 3 commercial fisheries conducted in 2010 to date: 2 gillnet [15 June (150 boats) and 21 June (164 boats)]. Total in-season commercial harvest estimates in Area 3 to date are: 8,623 sockeye, 0 coho, 48 pink, 311 chum and 367 Chinook. Area 3 commercial gillnet releases of salmon are: 274 coho, 116 chum and 95 Chinook. The next Area 3 gillnet fishery has been announced by DFO for Monday 28 June. 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 102 (Middle Clarence) Alaskan seine fishery began on 21 June. Total catches at Tree Point to date are approximately: 19,000 sockeye, 680 Chinook, 800 coho, 150 pink and 24,000 chum salmon. Total catches in the District 106 gillnet fishery to date are approximately: 13,000 sockeye, 500 Chinook, 28,000 coho, 550 pink and 1900 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 at the Nass fishwheels to date is 533 adults (208 tagged) and 68 jacks. The GW catch (186) of adult Chinook is below average (~700) based on mean catches from 1994-2009.

The Nass Chinook in-season run size estimate to Gitwinksihlkw to 24 June (4,734) is currently tracking below average (7,400) based on a mean run size to Gitwinksihlkw of 23,000 from 1994 to 2009. The recommended in-season run size target for adult Nass Chinook to Gitwinksihlkw in 2010 is 18,000. The net escapement estimate for Nass Chinook to date is ~4,150. The net escapement target is ~15,000.

The in-season run size estimate is calculated by a historical catch indices method where the cumulative daily catch of Chinook at FW1 and FW2 is multiplied by a range of annual historic catchability expansion factors from 1994-2009 results. A spreadsheet of the calculations and range of estimates under different fishwheel water level conditions is provided in the attachment.

It is too early to make any in-season forecasts of projected run size to GW or TRTC estimates for Nass Chinook. Pre-season TRTC forecasts range between 29,000 (minimum brood estimate) and 44,000 (maximum brood estimate). Based on the TRTC forecasts and the minimum escapement goal (10,000), the Nisga’a allocation of Nass Chinook ranges between 6,000 and 9,500. The sibling (age) TRTC estimate (33,000) will be used for calculating the initial target for the in-season Nisga’a allocation (7,000) of Nass Chinook. This target will be adjusted during the season based on in-season date. The actual allocation target may be up to 4,500 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 Chinook to week ending 19 June is 1,828. The current FSC catch (1,828) is just above average (1,500) for the 19 June week ending period based on 1994-2009 catches. Nisga’a FSC harvest of Chinook is anticipated to reach between 6,000 and 9,000 in 2010.

Area 3 commercial gillnet harvest of Chinook to date is 367 (95 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 1,180.

NASS COHO SALMON:

No coho salmon have been caught at the Nass fishwheels or in the Nisga’a fishery 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.

A total of 274 coho were released in the Area 3 commercial gillnet fishery to date. The total in-season harvest estimate of coho in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~28,800 to date.

NASS PINK SALMON:

No pink salmon have been caught at the Nass fishwheels or in the Nisga’a fishery. Pink salmon typically begin to be caught at the fishwheels in the first week of July.

Pre-season TRTC forecasts for Nass pinks range between 68,000 (minimum brood estimate) and 230,000 (maximum brood estimate) for two year, even 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.

A total of 48 pink salmon were harvested in the Area 3 commercial gillnet fishery to date. The total in-season harvest estimate of pink salmon in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is 700 to date.

NASS CHUM SALMON:

One chum salmon has been caught at the Nass fishwheels to date. Chum salmon typically begin to be caught at the fishwheels in the second week of July. No chum have been caught in the Nisga’a fishery to date.

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.

A total of 311 chum salmon (116 released) were harvested in the Area 3 commercial gillnet fishery to date. The total in-season harvest estimate of chum salmon in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is 25,900 to date.

The next Nass River public stock assessment update is planned for: Friday, 2 July.

An escapement update will also be available at the above website link on Tuesday, 29 June and Thursday, 1 July.

No comments: