Volpe et al snorkeled 40 Van Isle rivers in 1997 to 1999, looking for Atlantic salmon fry and adults. Farming started in 1985, and Volpe was working for DFO at the time of this research. I have fished more than 40 Van Isle rivers, so am interested to know those he looked at.
His work is contained in three PDFs, and I present a few snippets of the three documents coming close to 200 pages in total. Look at this post for the original document I have written on Volpe's work: https://fishfarmnews.blogspot.ca/2017/12/atlantic-salmon-in-bc-rivers-bad-news.html.
The fish farm industry started in 1985 and only five years later in 1990 Atlantics were documented in BC streams. This is shocking.
Here is part of the '97 text: "The first documented occurrence of free swimming Atlantic salmon identified in a B.C. coastal stream was in 1990 (Burt et al. 1992). Since then the frequency of reported sightings has increased significantly in both the marine environment (Thomson and McKinnell 1993; 1994; 1995; 1996; 1997) and freshwater (Lough et al. 1995; Lough et al. 1997)."
I will give you my comments and then have listed the rivers swum at the bottom of this post.
Those of you who are fisher dudes will be interested in the river specific information on Atlantics as well as hybridizing with browns, coho and steelhead. If you catch an Atlantic, usually identified most easily by their spotted gill covers, make sure to give it to DFO, but also find out if Volpe wants it. It should be frozen immediately. Volpe is on the web at: http://www.johnvolpe.ca/ that has a whole section on Atlantics in our ocean and rivers. Take a few images of your fish as well.
Here are the brief Trend notes of the 1997 swims:
Although these surveys provide only observational data which cannot be used to support
or refute certain hypotheses, trends in the data set are apparent and can be informative for
future work.
• Migrating adult Atlantic salmon observed in streams prefer to remain in relatively
large, mainstem waters and tend to avoid head water regions. It is possible that
increased salmonid densities (and putative competition) may be responsible for this
trend. Therefore it may be more effective in the future to concentrate surveys in the
lower sections of streams unless information to the contrary is available.
• No sex or size bias was apparent. Additionally a wide degree of overall health was
observed, from bright chrome fish with no sign of wear or disease to individuals with
significant fin wear and lethargy.
• Atlantics were seldom seen interacting with other salmonids - coho and steelhead
being the rare exceptions.
• Sexual maturation (i.e. colouration, kype development etc.) was not observed until
mid November in any individuals. It is likely that spawning does not occur until after
most fall spawning Oncorhynchus spp. have finished, if at all.
Here are the brief conclusions of the 1998 swims:
TRENDS and CONCLUSIONS
• The capture of at least two year classes of juvenile Atlantic salmon ends any debate regarding the potential for Atlantic salmon to successfully reproduce on this coast. The juveniles were found in typical habitat for the species and exhibited behaviours consistent with those published for wild fish in Atlantic drainages.
• As noted last year, migrating adult Atlantic salmon continue to prefer to remain in relatively large,
mainstem waters and tend to avoid head water regions. Increased salmonid densities (and therefore
competition) may be responsible for his trend. Therefore it may be more effective in the future to
concentrate surveys in the lower sections of streams unless information to the contrary is available.
• Sexual maturation (i.e. colouration, kype development etc.) was not observed in Atlantic salmon until October. It is likely that spawning does not occur until after most fall spawning Oncorhynchus spp. have finished, if at all.
Here are the brief notes of the 1999 swims:
Surveys began on July 13 and ended October 23. Approximately 90.7 km of river habitat was surveyed in 1999 and 213 adult and 176 juvenile Atlantic salmon were observed. Repeat observations of some individuals are likely on systems surveyed more than once. Because there is no way to effectively control for repeat observations over time (individuals cannot usually be discriminated), the number of repeat observations is unknown. Survey summary data are listed in Table 1. Data sheets for each survey including details of all Atlantic salmon observations are found in Appendix 1b.
DCR: And note the large number of Atlantics in the Salmon River: Approximately 110 adult Atlantic salmon were observed in and around what is known locally as the “clay bank pool”, 500m below the Cable House, on October 7. These adult Atlantic salmon were composed of two size classes, each equally represented. A small ~ 1.8-2.3 kg class and a large size class of individuals ranging from ~ 4.5-6.8 kg. Approximately 60% of both size classes showed obvious fin wear and net abrasions suggesting their presence was the result of a recent aquaculture escape event.
Here are the brief conclusions of the 1999 swims:
TRENDS and CONCLUSIONS
• Juvenile Atlantic salmon were identified in three river systems in 1999; the Adam R., Amor de Cosmos Cr. and the Tsitika R. This being the first year juveniles being identified in the former two systems, juvenile Atlantic salmon were first observed and captured in the Tsitika R. in 1998.
• Most juvenile Atlantic salmon identified to date have been observed in consistently similar habitats - relatively high gradient, fast water over large cobble / boulder substrate. All individuals have shown a benthic habit, defending small territories dominated by a home rock on which individuals sit atop of, resting on pectoral fins. In all cases juvenile Atlantic salmon shared habitats with sympatric rainbow trout / steelhead juveniles - but minimal interaction has been observed between the two species. Similar diets of the two species as juveniles may lead to trophic competition under limiting conditions.
• As noted in previous years, the majority of adult Atlantic salmon observed in freshwater river systems are found in mainstem waters and only rarely in lower order channels. To what degree this is a true reflection of Atlantic salmon preferences and to what extent this is a result of sampling bias is unknown. Survey effort on mainstem areas is disproportionate to total river length surveyed.
• Fin wear (particularly caudal and dorsal) is a common character among farm-reared fish. Of adult Atlantic salmon observed this year, roughly equal numbers showed fin wear as did not. Adults with fin wear were found only in the Adam / Eve R. and Salmon R. systems. In addition to these two systems, adults with intact fins were also found in Kokish R. and Zeballos R. Migratory adult Atlantic salmon with intact fins are indicative of i) a recent escapee without fin wear ii) an escapee with regenerated fin tissue iii) wild reared feral individual. No data are available to evaluate the potential likelihood of each of these three scenarios. It would be extremely informative to know if any captured migratory adult Atlantic salmon with intact fins exhibited scale / otolith growth patterns consistent with being reared in the wild and if so, what proportion?
***************
Here are the rivers that were looked at in 1997 and those that I have fished are bold faced, just a selection of the +40 I have fished.
Please note that I am surprised some other rivers were not swum, but there is cost and there is time, I suppose: the
Big Qualicum, Quinsam, Nahwitti, Marble (only swum in one year), Stamp,
Sproat, Taylor, Nahmint, Pachena, Henderson, Toquart, Grice,
Gold/Muchalet, Sucwoa, Tahsis, Somass, Gordon, Harris, Loss, Caycuse,
Nitinat and the Klanawa.
The rivers:
East Coast Vancouver Island:
Adam & Eve Rivers
Heath Creek (Gilford Island)2
Kokish River
Nimpkish River
Salmon River
Songees Creek
Quatse River
Viner Creek (Gilford Island)
West Coast Vancouver Island: Bedwell/Ursus River
Cayhegle River
Colonial River
Heath Creek
Leiner River
Marble River
Moyeha River
Zeballos River
The following streams were added in-season in response to reports of Atlantic salmon
activity either in the system or more commonly, in the adjacent marine environment:
Ayum Creek
Englishman River
Lake of the Mountain Creek
Little Qualicum River
Muir Creek
Naka Creek
San Juan River
Sooke River
Tugwell Creek
The following streams were selected for electrofishing surveys:
Boot Lagoon, Great Central Lake
Coal Creek
Colonial River
Cowichan (Lower) / Koksilah River
Dalrymple Creek
Rosewall Creek
Pye Creek
Whitehouse Creek
These are the streams and rivers he snorkeled in 1998:
East Coast Vancouver Island:
Adam & Eve Rivers
Cluxewe River
Kokish River
Nimpkish River
Salmon River
Scotia Creek
Songhees Creek
Quatse River
West Coast Vancouver Island:
Bedwell/Ursus River
Cayhegle River
Colonial River
Leiner River
Moyeha River
Zeballos River
"The following streams were added in-season in response to reports of Atlantic salmon activity in the area or because the system possessed habitat deemed by the monitoring crew likely to attract adult spawning Atlantic salmon:"
Amor de Cosmos Cr.
Campbell River
Kaouk River
Kennedy River
Lake of the Mountain Creek
South Sarita River
Tsitika River
White River
The following streams were identified for electrofishing surveys:
Boot Lagoon, Great Central Lake
Coal Creek
Colonial River
Cowichan (Lower) / Koksilah River
Dalrymple Creek
Rosewall Creek
Pye Creek
Whitehouse Creek
And in 1999, the following were snorkelled:
East Coast Vancouver Island:
Adam & Eve Rivers
Amor de Cosmos Creek
Campbell River
Cluxewe River
Keogh River
Kokish River
Nimpkish River
Salmon River
Tsitika River
Quatse River
West Coast Vancouver Island:
Cayeghle River
Colonial River
Leiner River
Zeballos River
The following streams with Atlantic salmon culture facilities were also identified for surveys:
Coal Creek
Colonial River
Cowichan (Lower) / Koksilah River
Kokish River
Lake of the Mountain Creek
Rosewall Creek
Songhees Creek
Pye Creek
No comments:
Post a Comment