Nass Update to July 31st

Nass Update to July 31st. Information provided courtesy/copyright Nisga'a Fisheries.
We've moved the Steelhead Section to near the top for convenience.



2009 NASS RIVER STOCK ASSESSMENT UPDATE

Attached is a stock assessment summary update for the Nass River (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/

(Note: 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 Thursday 30 July 2009.

GITWINKSIHLKW (GW) FISHWHEELS (TEST FISHERY - 16TH YEAR): Fishwheels 1 and 2 were started on 1 June for tagging and historical catch index assessments for salmon and steelhead. The fishwheels were shutdown during the high water period (2-15 June) and re-started on 16 June. Fishwheels 1 and 2 are currently operating well at above average water levels (3.2 m vs. 1.9 m average (92-08)). All fish caught in the Gitwinksihlkw fishwheels have been released.

GREASE HARBOUR (GH) FISHWHEELS (~17 KM UPSTREAM OF TEST FISHERY): Up to four fishwheels were operated at Grease Harbour (upstream of Ts'im Anwiihlist) in 2009 for in-season mark-recapture tag recoveries and some selective harvesting of sockeye, Chinook and coho based on Nisga’a entitlement levels and targets as directed by Nisga’a Lisims Government. The GH fishwheel start-up dates were: 17 June (FW6), 23 June (FW3), 25 June (FW5) and 7 July (FW4). All four fishwheels are currently operational.

NASS SUMMER-RUN STEELHEAD:

In-season run size estimates or other information 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.

The fishwheel catch of Nass steelhead (26) to 30 July is below average (58) based on fishwheel operations from 2000 to 2008. However, steelhead catches (11) at the Gitwinksihlkw fishwheels to week ending, 25 July, are average (94-08 average is 11).

The run size estimate of Nass summer-run steelhead to Gitwinksihlkw to 30 July is 700 with ~6% (94-08 median) of the run estimated to have passed Gitwinksihlkw to date. The current estimate is above average (545) based on the mean returns from 1994 to 2008. During typical Gitwinksihlkw fishwheel operation (July to early to mid September), the preliminary run size target for Nass summer-run steelhead to Gitwinksihlkw is ~4,200 depending on any losses projected above Gitwinksihlkw. The mean run size estimate to Gitwinksihlkw from 1994 to 2008 is ~8,500.

The run size estimates will be a combination of mark-recapture and historical catch indices methods at GW fishwheels. Mark rates derived from the coho assessment program are used to generate summer-run steelhead estimates that assume similar catchability between coho and steelhead at the GW fishwheels based on similar run timing patterns. Mark-rate sample sizes are much larger and more reliable for coho than using steelhead mark rate data. Steelhead run size estimates will change over a 7 day period due to coho mark rates stabilizing at Grease Harbour as tagged fish at Gitwinksihlkw pass the upstream Grease Harbour fishwheel sites over a 7 day period.

The net run size estimate above Grease Harbour for Nass summer-run steelhead is 699. The net run size target for Nass summer-run steelhead above Grease Harbour is ~4,000 during typical operations of the Gitwinksihlkw fishwheels from July to first or second week of September.

Total counts of steelhead at Meziadin Fishway to date are: 0 adults (0 adipose marks). The 2009 cumulative adult count (0) to date is the same as the average (0) based on mean counts at the Meziadin Fishway from 1994 to 2008. The average count of steelhead during operation of Meziadin Fishway (July to mid-October) from 1994 to 2008 is 30. Steelhead begin passing the Fishway in late August.

The Nisga’a harvest estimate of Nass steelhead to week ending 25 July is 66. The average harvest of Nass summer-run steelhead in Nisga’a Fisheries is ~400 from 1994 to 2008.

The next Nass River stock assessment update is planned for: Friday, 7 August. An escapement update will also be available on Tuesday, 4 August at the above website link.



NASS SOCKEYE SALMON:

The Nass sockeye run size estimate to Gitwinksihlkw to 30 July (182,285) is currently tracking at below average (195,000) abundance level based on a mean run size to Gitwinksihlkw of 278,000 from 1994 to 2008.

The run size estimate is a combination of mark-recapture and historical catch indices methods. Note that mark-recapture estimates will change over a 5 day period due to mark rates stabilizing at Grease Harbour as fish tagged at Gitwinksihlkw pass the upstream Grease Harbour fishwheel sites over a 5 day period. After the mark rate stabilizes, the daily estimate is better at predicting actual catch efficiencies at the GW fishwheels than the historical indices. As such we will use historical catch efficiencies during the 5 d fluctuating period while mark-recapture estimates are stabilizing for less fluctuating estimates that are reported. Currently, mark-recapture estimates are final to 25 July and later dates will fluctuate as additional catch and tag recovery data become available from the GH fishwheels. A spreadsheet of the calculations and range of estimates is provided in the attachment.

The recommended run size target for adult Nass sockeye to Gitwinksihlkw is 275,000 depending on harvests projected above Gitwinksihlkw. Although the net escapement goal (200,000) for Nass sockeye has been achieved at lower in-season aggregate run size targets (225,000 to 250,000) in seven of the past nine years since the implementation of the Nisga’a treaty, the Meziadin goal (160,000) has only been achieved in two years of the past nine years. Therefore, Nisga’a Fisheries has recommended to DFO that the run size target be increased to 275,000 in 2009 to have a greater certainty of reaching the Meziadin River escapement which has represented 51% to 85% (avg. is 68%) of the total Nass sockeye aggregate population since 1994.

Using final mark-recapture estimates to 25 July, preliminary forecast methods are currently predicting to be below the run size target to Gitwinksihlkw (275,000) with estimates ranging between 265,000 (range 248,000-281,000 using mean run timing method) and 269,000 (in-season to final method) using two different methods. If the run timing is the same as last year (see below), the forecast would be lower (227,000).

The net escapement estimate for Nass sockeye to date is ~154,000. The current net escapement target is ~200,000 (160,000 to Meziadin River and ~40,000 to non-Meziadin systems). However, as noted above, to reach the Meziadin escapement goal, the net escapement target may need to be as large as 215,000.

Meziadin Fishway opened on 1 July for escapement counts to the river. Total counts of sockeye at Meziadin to 30 July are: 66,881 adults (1550 tags) and 1841 jacks. The 2009 cumulative adult count to date is average (66,000) based on mean counts at the Meziadin Fishway from 1994 to 2008. The average count of adult sockeye from 1994 to 2008 is 169,000. The fishwheel mean-run timing forecast is predicting ~153,000 sockeye (range: 123,000-187,000) to reach the Fishway based on current escapement passed GW, estimated mean stock composition (68%; 1994 to 2008) and projected harvests (40,000) above GW. In-season to final fishway count (167,000) and Meziadin mean count (160,000) methods are projecting slightly higher forecasts to reach the fishway in 2009 using those methods. Nisga’a Fisheries estimates that ~42% of the Meziadin sockeye run has reached the Fishway to date based on mean counts from 1990 to 2008.

Depending on the cumulative run timing estimate used to date, the in-season Nass sockeye projected TRTC is between 385,000 (using a more advanced run timing like 2008 - 81%) and 445,000 (using 93-08 median run timing and entitlement - 70%) and continues to track well below the pre-season TRTC and entitlement estimate (511,000 TRTC; 86,000 entitlement). The in-season Nisga'a entitlement of Nass sockeye ranges between ~58,000 and 72,000 to date using the in-season TRTC projections. As a result of the downsizing of the TRTC and entitlement amounts from pre-season levels, Nisga'a sale fisheries on sockeye are closed until further notice. We believe the run is more advanced than the median estimate based on the high number of jacks and larger fish observed over the past week or so that typically suggest a more advanced run timing. Age results will be available next week to help confirm these observations. The attachment shows the median run timing estimate but includes two escapement forecast charts, one for the median run timing forecast and the other a more advanced run timing (2008). The 2009 pre-season TRTC return was expected to be below average (636,000) based on TRTC returns from 1994 to 2008.

Nisga’a food fish (FSC) harvesting is open for all salmon species and is anticipated to reach between 20,000 and 30,000 for Nass sockeye in 2009. Given that the total FSC amount was projected to not exceed the total Nisga’a entitlement estimate for 2009, the remaining entitlement (~30,000 to 60,000 sockeye) was available for sale fisheries. Therefore, the Director of Nisga’a Fisheries and Wildlife Department opened the Nisga’a individual and communal-sale fisheries for harvesting Nass sockeye as announced by the Nisga’a Fisheries and Wildlife Department.

The total Nisga’a harvest estimate of Nass sockeye to date is 56,769. The total includes FSC catch (11,227) to week ending 25 July and sale fishery catch estimates to date (37,280 from individual sales and 8,262 from communal sales from GH fishwheels). The next Nisga’a catch estimate for week ending 1 August will be updated on Wednesday, 5 August.

Eight 12-hr Nisga’a marine individual sale fisheries have occurred to date: 25 June (33 boats), 26 June (33 boats), 2 July (30 boats), 3 July (30 boats), 9 July (25 boats), 10 July (23 boats),16 July (17 boats) and 17 July (17 boats) in Area 3-12. Total harvests in the Nisga’a marine sale fisheries to date are: 16,373 sockeye; 20,891 pink; 240 Chinook and 30 coho. The marine sale fishery is closed until further notice.

Six 10-hr Nisga’a in-river individual sale fisheries have occurred to date: 8 July, 15 July, 17 July, 19 July, 21 July, and 23 July. The in-river sale fishery is closed until further notice.

Area 3 commercial fisheries conducted in 2009 to date have been 10 gillnet [16 June (146 boats), 23 June (224 boats), 29 June (253 boats), 30 June (253), 6 July (264 boats), 7 July (229 boats), 13 July (258 boats), 4 July (224 boats), 20 July (164 boats) and 21 July (157 boats)] and 7 seine [13 July (19 boats),16 July (39 boats), 20 July (19 boats), 21 July (19 boats), 24 July (6 boats), 25 July (23 boats) and 27 July (19 boats). Total in-season commercial harvest estimates in Area 3 to date are: 104,259 sockeye; 886,605 pink; 46,427 chum and 1,296 Chinook (source of data is from DFO Prince Rupert Fisheries Management).

Alaskan gillnet fisheries in Districts 101 (Tree Point) and 106 (Sumner and Upper Clarence) began on 21 June and 15 June, respectively. Alaskan seine fisheries opening dates were: Districts 101 (Lower Clarence/Revilla; opened on 5 July), 102 (Middle Clarence; opened on 21 June), 103 (Cordova; not opened yet) and 104 (Noyes/Dall; opened on 5 July).

Total in-season harvest estimates of sockeye in southeast Alaskan gillnet and seine fisheries in the above Districts is 183,805 based on data to week ending 30 (25 July) on the ADFG website. An attachment is provided showing the in-season breakout of catch by the respective district areas. The reported catches are below average (245,000) to the week ending period. The average total catch of sockeye in southeast Alaskan fisheries is 660,000 sockeye from 1999 to 2008. Of the Alaskan total catch of sockeye, Nisga’a Fisheries estimates that approximately 59,000 are Nass sockeye based on average stock % data (1982-07) and is below average (86,000) to date. The average total catch of Nass sockeye in Alaskan fisheries is 156,000 from 1999 to 2008, and 185,000 in odd-years when targeting pinks.

NASS CHINOOK SALMON:

The Nass Chinook run size estimate to Gitwinksihlkw (22,498) is tracking above average (21,800) to 30 July based on a mean run size to Gitwinksihlkw of 23,000 from 1994 to 2008. The run size target for Nass Chinook to Gitwinksihlkw is 17,000 depending on harvests projected above Gitwinksihlkw. The run size target for 2009 has been reached based on in-season data.

The in-season tracking of the Nass Chinook run to Gitwinksihlkw predicted 23,000 as the final in-season run size total to Gitwinksihlkw using the two methods (in-season to final and mean run timing methods. Nisga’a Fisheries estimates that 97% (93-08 median) of the run has passed Gitwinksihlkw to date.

The net escapement estimate for Nass Chinook is 19,798. The net escapement target for Nass Chinook above Grease Harbour is ~15,000 and has been reached based on in-season data.

Total counts of Chinook at Meziadin Fishway to 30 July are: 111 adults (0 tags) and 4 jacks. The 2009 cumulative adult count to date is currently below average (145) based on mean counts at the Meziadin Fishway from 1994 to 2008. The average count of adult Chinook at Meziadin Fishway from 1994 to 2008 is 480. The fishwheel mean-run timing forecast is predicting ~500 Chinook (range: 490-510) to reach the Fishway based on current escapement passed GW and estimated mean stock composition (2.6%; 1994 to 2008). Nisga’a Fisheries estimates that ~34% of the Meziadin Chinook run has passed the Fishway to date based on mean counts from 1990 to 2008. Mark-recapture data for final escapement estimates will be based primarily on Meziadin and Kwinageese weir counts and tag recovery information. Kwinageese weir operations began on 12 July.

The Kincolith video-counting fence will not operate in 2009 due to water levels not cooperating for fully installing the weir after removing the log jam above the weir in the early summer months. The weir is beneficial to collecting escapement data for the Kincolith River and providing an index of escapement of salmon to coastal streams in Area 3. A mark-recapture study is currently being conducted on Kincolith Chinook to estimate the number of Chinook that passed to the spawning areas in 2009.

Nisga’a Fisheries is using a preliminary TRTC estimate for Nass Chinook of between 32,000 (in-season) and 48,000 (pre-season) for tracking the Nisga’a entitlement of Nass Chinook. The 2009 pre-season TRTC estimate was forecasting for an above average (36,000) return based on TRTC returns from 1994 to 2008; but in-season assessments are suggesting a below average return. Uncertainty of marine commercial and recreational catches of Nass Chinook make it difficult to accurately estimate in-season TRTC estimates for Nass Chinook. However, based on the current TRTC estimate for 2009, the Nisga’a entitlement of Nass Chinook is between ~7,000 and ~10,000. An additional allocation is also available as an underage (3,900) provision based on past year’s management uncertainty allowances; however, underages are only targeted in productive return years as assessed during the season.

The Nisga’a harvest estimate of Nass Chinook to date is 5,002. The total includes FSC catch (3,405) to week ending 25 July and sale fishery catch estimates to date (566 from individual sales and 1031 from communal sales from GH fishwheels).

Area 3 commercial gillnet harvest of Chinook to date is 1,296 (1547 released). No estimates of the Nass component are currently available to Nisga’a Fisheries.

Total in-season harvest estimate of Chinook in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is 5,036 based on data to week ending 30 (25 July) on the ADFG website. Reported catches are average (4,900) to date. The average total catch of Chinook in southeast Alaskan gillnets and seine fisheries in Districts 101 to 104 is ~13,000 Chinook from 2000 to 2008. No estimates of the Nass component are currently available to Nisga’a Fisheries.

NASS COHO SALMON:

The run size estimate of Nass coho to Gitwinksihlkw to 30 July is 6,024 with ~4% (93-08 median) of the run estimated to have passed Gitwinksihlkw to date. The current estimate is above average (2,300) based on the mean returns from 1994 to 2008. The run size target for Nass coho to Gitwinksihlkw is ~65,000 depending on harvests projected above Gitwinksihlkw and during typical Gitwinksihlkw fishwheel operation (July to early-mid September) as coho continue to pass the fishwheels after the fishwheel program ends operation. The mean run size estimate to Gitwinksihlkw from 1994 to 2008 is 68,000.

The in-season run size estimate for Nass coho will be a combination of mark-recapture and historical catch indices methods. The mark-recapture estimates will fluctuate over a 7 day period due to mark rates stabilizing at Grease Harbour as coho tagged at Gitwinksihlkw pass the upstream Grease Harbour fishwheel sites over the 7 day period.

The net escapement estimate for Nass coho is ~5,991. The net escapement target for Nass coho above Grease Harbour is ~60,000 during typical operations of the Gitwinksihlkw fishwheels from July to first or second week of September.

Total counts of coho at Meziadin Fishway to 30 July are: 0 adults (0 tags) and 0 jacks. The 2009 cumulative adult count to date is the same as the average (0) based on mean counts at the Meziadin Fishway from 1994 to 2008. The average count of adult coho at Meziadin Fishway from 1994 to 2008 is 3700. Coho begin passing the Fishway typically in late August.

Nisga’a Fisheries is currently using a preliminary TRTC estimate for Nass coho of 119,000 (pre-season) for tracking the Nisga’a entitlement of Nass coho that is ~9,500. An additional allocation is also available as an underage (6,263) provision based on past year’s management uncertainty allowances; however, underages would only be targeted in productive return years as assessed during the season. The 2009 pre-season TRTC estimate is projecting for a below average (162,000) return based on TRTC returns from 1994 to 2008. Uncertainty of marine commercial and recreational catches and lower/coastal Nass coho escapement make it difficult to accurately estimate in-season TRTC estimates for Nass coho. However, forecast methods continue to be developed to assist in reaching escapement and entitlement targets.

The Nisga’a harvest estimate of Nass coho to date is 192. The total includes FSC catch (153) to week ending 25 July and sale fishery catch estimates to date (39 from individual sales and 0 from communal sales from GH fishwheels).

Area 3 commercial gillnet and seine harvests of coho to date are 0 (8,779 released). No estimates of the Nass component are available to Nisga’a Fisheries.

Total in-season harvest estimate of coho in Southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is 88,252 based on data to week ending 30 (25 July) on the ADFG website. Reported catches are just above average (87,000) to date. The average total catch of coho in southeast Alaskan gillnets and seine fisheries in Districts 101 to 104 is ~370,000 coho from 2000 to 2008. No estimates of the Nass component are available to Nisga’a Fisheries.

NASS PINK SALMON:

The total fishwheel catch (4,825) of pink salmon to 30 July is below the mean catch (12,200) for odd-year returns from 2000 to 2008. However, pink catches (2170) at the Gitwinksihlkw fishwheels to week ending, 25 July, are average (odd year average between 1992 and 2008 is 2068).

Nisga’a Fisheries is currently using the pre-season TRTC estimate for Nass pinks of 1,053,000 for tracking the Nisga’a entitlement (129,000) of Nass area pinks. The 2009 TRTC estimate is projecting to be just below average (1,150,000) based on TRTC returns of odd year pinks from 1995 to 2007.

Note that pre-season and in-season forecasting of Nass area pinks are poorly developed for Area 3 currently. Nisga’a Fisheries is developing in-season methods with DFO for better predicting the magnitude of returns in the future based on fishwheel mean catches, Kincolith weir counts (when operated) and any stream survey information that can be collected (primarily from late July and early August data) to aid in managing Nass area pinks and tracking the Nisga’a entitlement.

The Nisga’a harvest estimate of Nass pinks to date is 26,806. The total includes FSC catch (5,874) to week ending 25 July and sale fishery catch estimates to date (20,932 from individual sales fisheries).

Area 3 commercial gillnet and seine harvest of pink to date are: 886,605 (910 released).

Total in-season harvest estimate of pink salmon in Southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is 2,013,000 based on data to week ending 30 (25 July) on the ADFG website. Reported catches are below average (3,500,000) for week ending period catches of odd-year pink returns. The average total catch of pink in southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is ~28,000,000 pink from odd year returns between 1999 and 2008. No estimates of the Nass component are available to Nisga’a Fisheries.

NASS CHUM SALMON:

The total fishwheel catch of chum salmon (11) to 30 July is below the mean catch (24) level based on total fishwheel catches from 2000 to 2008. However, chum catches (7) at the Gitwinksihlkw fishwheels to week ending, 25 July, are just above average (92-08 average is 5).

Nisga’a Fisheries is currently using the pre-season TRTC estimate for Nass chum of 56,000 for tracking the Nisga’a entitlement (4,480) of Nass chum. The 2009 TRTC estimate is projecting a below average (93,000) return based on TRTC returns from 1994 to 2008. In addition, for the past two years the returns of Nass area chum have been well below the minimum escapement goal and concern for stock status has been raised by Nisga’a Fisheries to DFO. The overall stock status of Nass area chum since 2000 has prevented the opportunity to utilize the Nisga’a entitlement underages (~28,000) that occurred in the early years of implementing the Nisga’a treaty (2000 to 2002). When returns have been above the escapement goal, the majority of the Nisga’a entitlement of Nass area chum has been foregone since 2002 in an attempt to rebuild stocks.

Note that pre-season and in-season forecasting of Nass area chums are poorly developed for Area 3. No reliable methods are currently available to estimate escapement during the season, track the status of the run or the Nisga’a entitlement.

The Nisga’a harvest estimate of Nass chum to date is 80. The total includes FSC catch (80) to week ending 25 July. No Nisga’a sale fisheries for Nass chum are being permitted in 2009 to allow stock rebuilding in Area 3.

Area 3 commercial gillnet harvest of chum to date is 46,427 (24,936 released). No estimates of the Nass component are available to Nisga’a Fisheries.

Total in-season harvest estimate of chum in Southeast Alaskan gillnet and seine fisheries in Districts 101 to 104 is 788,128 based on data to week ending 30 (25 July) on the ADFG website. Reported catches are well above average (582,000) to week ending period reported. The average total catch of chum in Southeast Alaskan gillnets and seine fisheries in Districts 101 to 104 is ~1,500,000 chum from 1999 to 2008. No estimates of the Nass component are available to Nisga’a Fisheries.