DFO WCVI Bulletin, Observations to Nov 12, 2010
SUMMARY:
For 2010 large amounts of rainfall and, in some cases flooding, have made escapement surveys challenging. For some systems fewer than optimal surveys have been conducted and this will contribute to greater uncertainty in final escapement estimates -i.e. in some cases estimates will be biased low. Also, please note the observations for 2010 reported below are the ‘peak counts’ observed to date; they do not represent an estimate of total escapement.
Similar to the pattern observed in 2008 and 2009, Chinook escapement levels are about the recent 12¬year average in the NWVI region (DFO Statistical Areas 25 to 27), but below average in the SWVI region (DFO Statistical Areas 20 to 24). Chinook escapements remain particularly low in Clayoquot Sound (Area 24). With the exception of the San Juan area, coho escapements are about the recent 12-year average. Chum escapements throughout the WCVI are well below recent 5 and 12-year averages.
2010 EXPECTATIONS:
Chinook: Approximately 43,000 Somass Chinook are forecast to return to Barkley Sound and Alberni Inlet in 2010. For other WCVI Chinook populations, expectations are for below-average returns: Conuma Hatchery Terminal Return: 5000 – 14,000; Nitinat Terminal: 10,000; Nahmint River: <100; San Juan River: 1000 – 3000; WCVI Wild about 6000 total (~40% of average observations since 1995).
Coho: Most coho returning to WCVI systems in 2010 are 3-years from the 2007 brood year. Return expectations are based on forecast marine survival rates of the brood, which are below average at 1% for the Roberstson Creek hatchery indicator stock. However, forecast model predict a much higher survival rate of 10% for the wild indicator stock (Carnation Creek).
Chum: WCVI chum forecasts for 2010 are well below average returns at about 83K, 24K, 35K, 69K and 35K for Nitinat, Barkley, Clayoquot, Nootka and Kyoquot terminal areas, respectively.
Sockeye: The 2010 Somass (Great Central and Sproat Lake) sockeye return is in the range of 1.2 to 1.4M adults, far exceeding pre-season expectations. Observations suggest returns of other WCVI sockeye populations are also relatively abundant compared to recent year averages.
METHODOLOGY:
Since 1995, escapements to about 18 systems throughout the WCVI have been surveyed annually by DFO-contracted crews with a consistent methodology. These crews count spawners several times over the duration of the run. Spawners are usually counted during swims, but other methods may be used, such as aerial surveys or bank walks. The counts are compiled and analyzed (using the area-under-the-curve method) to estimate total escapement. Although other species are observed and recorded, the timing and methodology of these surveys is most conducive to generating estimates of Chinook, coho and chum escapement.
More precise escapement data are also gathered through indicator stock programs (e.g. Somass sockeye and Chinook, Carnation Creek coho). Less precise data are gathered through surveys sponsored by local First Nations, stewardship groups and Charter Patrol operators.
PORT RENFREW (AREA 20):
Escapement to the San Juan River is monitored at the counting fence operated by the San Juan enhancement society until high water necessitates the removal of the fence. After that, the Pacheedaht First Nation will conduct swim surveys once per week for a total of 4 swims (depending on river conditions). Escapement to Harris and Lens creeks will also be surveyed by the Pacheedaht First Nation.
Since 1995, average escapement to San Juan River is about 2000 and 17,000 for chinook and coho, respectively.
2010 observations indicate well below average escapement of both chinook and coho to the San Juan River with peak observations of < 500 chinook and < 4000 coho.
NITINAT (AREA 21, 22):
Nitinat River will be surveyed by DFO StAD and Nitinat Hatchery. Four surveys are scheduled. Hobiton Creek sockeye run is currently monitored by Ditidaht First Nation and the Nuu-chah-nulth Tribal Council (NTC). Two surveys are scheduled for the Klanawa River during peak Chinook and Chum timing, to be conducted by Huu-ay-aht First Nation and DFO.
Since 1995, average escapement to the Nitinat River is about 21,000 and 200,000 for chinook and chum,
respectively. Surveys of the Nitinat River are not conducive to estimating coho abundance. 2010 observations indicate a peak escapement of about 4500 of Chinook to Nitinat River, which although below average is about expected levels. Escapement of chum to the Nitinat Lake and River is well below average, estimated at about 90,000 near forecast.
SOMASS KEY STREAM (AREA 23):
The Somass system is a ‘key stream’ for sockeye, chinook and coho. In partnership with the Hupacasath First Nation, DFO operates counting operations at various sites from May to October. Estimated Somass salmon escapement to date is:
Sockeye: 430,000. Chinook: 25,000. Coho: 21,000 Major chum spawning areas occur below Stamp Falls and therefore are not included in the counts.
GREATER ALBERNI INLET/BARKLEY SOUND (AREA 23):
The Sarita River is surveyed by Huu-ay-aht First Nation and DFO. Four surveys are scheduled for the 2010 season. Clemens Creek and Nahmint River are surveyed by DFO in partnership with the Uchucklesaht First Nation and Nuu-chah-nuulth Tribal Council Four and seven surveys are scheduled for each, respectively.
Since 1995, the average escapement to Sarita River was about 2000 and 14,000 for chinook and chum, respectively. Surveys of the Sarita River are not conducive to coho estimates. Since 1995, the average escapement to the Nahmint River was about 500, 40,000 and 400 for chinook, chum and coho, respectively.
2010 observations indicate below average escapement of chinook to both the Sarita and Nahmint Rivers with peak counts to date of < 900 to Sarita and <400 to Nahmint. It should be noted that although Nahmint escapement is below the 15-year average, it is higher than recent year averages and has likely benefitted from enhancement efforts from the 2006 brood year. Chum escapements to Area 23 are well below average. Coho escapements are about recent year averages and higher than expected.
CLAYOQUOT (AREA 24):
Megin, Bedwell/Ursus, Cypre, Tranquil, and Kennedy Rivers are surveyed by DFO in partnership with the Ahousaht and Tloquiaht First Nations and the Tofino Enhancement Society and the Thorton Creek Hatchery. About 5-6 surveys are planned at a frequency of about once per week, depending on river conditions. There are also plans to survey a number of other systems for chum escapements including Ice, Sydney, Atleo and some systems in Hesquiaht. In addition, for 2010, there are mark-recapture studies operating on the Moyeha and Tranquil Rivers to generate more precise estimates of chinook escapement.
For 2010, peak counts to date indicate that escapement of Chinook to Area 24 systems remains very low, although there may some modest improvement relative to 2008 and 2009 levels. Observations indicate escapement of coho to Area 24 systems is about recent 12-year averages. Chum escapements are below average with the exception of the Tranquil River.
NOOTKA / ESPERANZA (AREA 25):
The Tahsis, Leiner, Conuma, and Burman Rivers are surveyed by DFO in partnership with the Mowachaht/Muchalaht First Nations and Nootka Sound Watershed Society (NSWS) members. For 2010, 5-6 surveys are planned at a frequency of about once per week, depending on river conditions. The
Charter Patrol operator will also survey a number of systems in Area 25 with assistance by Ehatisaht First Nation. For 2010, there are also mark-recapture studies for chinook operating on the Tahsis and Burman River.
2010 observations indicate Chinook escapements to Area 25 systems are similar to the recent 5-year average (i.e. lower than the longer-term 12 year average, but stable). Coho escapements are about the 12-year average for most systems. Chum escapements are well below average.
KYUQUOT (AREA 26):
In Area 26, the Kaouk, Artlish and Tahsish Rivers are surveyed by DFO in partnership the North Vancouver Island Salmon Enhancement Society and Kyuquot First Nations. 5 surveys are planned this year at a frequency of about once per week, depending on river conditions. For 2010, there is a mark-recapture study for chinook operating on the Kaouk River.
2010 observations of Chinook escapements to Area 26 systems are variable and likely influenced by poor survey conditions. Chinook escapement to the Kaouk River is above the 12-year average, whereas there are below average observations in the two other indicator systems (Artlish, Tahsish). Coho escapements are about the 12-year average for most systems. Chum escapements are well below average.
QUATSINO (AREA 27):
In Area 27, the Marble, Colonial/Cayeghle Rivers are surveyed by DFO in partnership the North Vancouver Island Salmon Enhancement Society. 5 surveys are planned this year at a frequency of about once per week, depending on river conditions.
2010 observations indicate Chinook escapements to Area 26 systems are similar to the recent 5-year average (i.e. lower than the longer-term 15 year average, but stable). Coho escapements are about the 15-year average for most systems.
For more information contact: Cora Moret WCVI Salmon Field Program Coordinator Telephone (250) 756-7006, Fax (250) 756-7162 E-mail:
cora.mora@dfo-mpo.gc.ca
