Flooding - a problem for fish? - James Hunt, The Tweed Foundation
•Transferir como PPTX, PDF•
1 gostou•235 visualizações
Talk provided during the Scottish Fisheries Co-ordination Centre Annual Biologist's Meeting, February 3rd and 4th 2016, Milton Birnam Hotel
Recomendados
Mais conteúdo relacionado
Mais procurados
Mais procurados (20)
Destaque
Destaque (18)
Semelhante a Flooding - a problem for fish? - James Hunt, The Tweed Foundation
Semelhante a Flooding - a problem for fish? - James Hunt, The Tweed Foundation (7)
Mais de Scottish Fisheries Co Ordination Centre
Mais de Scottish Fisheries Co Ordination Centre (20)
Último
Último (20)
Flooding - a problem for fish? - James Hunt, The Tweed Foundation
- 1. Salmon Fry Ecology Flooding – a problem for fish?
- 2. Flooding at spawning time
- 3. Flooding at spawning time
- 4. January flooding SITE 1994 1999 2004 BK03 51 93 170 TT04 89 106 199 TT02 30 191 69 SITE 1994 1999 2004 BK03 51 37 46 TT04 60 49 41 TT02 14 17 29 2005 148 118 172 2005 45 33 19 Salmon Fry Salmon Parr
- 5. Spring flooding SITE CODE 2006 37 34 1 14 2 30 3 36 7 24 8 46 11 13 2009 46 56 46 90 21 2010 7 2 3 7 1 15 Upstream
- 7. Juvenile monitoring example SITE CODE 2006 2009 2010 37 34 46 7 1 14 56 2 2 30 46 3 36 90 3 7 24 21 7 8 46 1 11 13 15 2011 19 1 6 61 123 39 66 2012 19 6 35 40 40 39 Upstream
- 8. A benefit of large flood events? 5th,6th,7th September 2008 July 2009
Notas do Editor
- Based on data recently released by the Met Office, December 2015 was the wettest calendar month on record (in a series from 1910). Many of you will have to stand up in front of boards or angling clubs and provide our opinion on whether fish stocks will be affected. And this really touches on one of the functions of the SFCC which is to “encourages discussion of fisheries science and management in a forum informed by data driven evidence,” We know that Salmon are a resilient species, but how much can they put up with? Expertise of ian and Ross to chip in and after these presentations it is very much up to you to decide if there is anything that can be taken forward My presentation I would like to consider the consequences of flooding at three different times of year – Spawning time, mid-winter and spring time and we have three strands of evidence for the consequences.
- In the battle for the most dramatic flooding pictures, 31st October 1977, a slow moving autumn storm caused the joint highest flow ever recorded on the Ettrick Water (with 1926) and memorably caused the loss of the Philiphaugh Bridge and inundation along Ettrickhaugh Road, Riverside and Lindean: 560m3 sec. compared to an average of 8.9 What was the consequence? This was pre-electro-fishing monitoring so was there an effect on the catches? We know that most of our Springers come from the Ettrick, so let’s look at specifically Spring catches
- When did catch and release come in? There is evidence for the reduced catches every fifth year being due to reduced numbers of 2.2 type Salmon from the scale reading monitoring programme which has been carried out by the Tweed Foundation since 1991 ( the same survey was made by the then OAFS in 1989 as well). As can be seen from this graph, in "Normal" years, the percentage of 2.2 fish is between 70% and 85%, but in the years 1992 and 1997, when catches were poor, this percentage fell to 62% and 60%: Nos of fish caught in sample fisheries before the 1st July in recent seasons and the % of them that were 2.2 Salmon This indicates that low total "Spring" catches are associated with low numbers of 2.2 fish, also showing that that when 2.2 type Salmon are scarce, their numbers are not made up by fish of other types, such as 1.2 or 3.2. 7 As shown in both the graphs above, 1993 was also a year of poor "Spring" catches, but the fact that the percentage of 2.2 fish in those catches was a "normal" 70% is an indicator that the low catches were not due to a failure of the key 2.2 type of Salmon but to some other reason -. perhaps a season of poor "fishability". 9 Ettrick Salmon, being early-running fish, are early-spawners, with peak spawning in the last week of October and the first week in November. This flood therefore occurred at the precise time and place to have had a very severe impact on the spawning success of "Spring Salmon" that year, and five years later, the "Spring" catches of 1982 were very poor. No connection can, of course, now be proven, but the timing and location are highly suggestive. 10 The question that needs to be answered is how this cycle of poor years has persisted? Not all Ettrick I "Spring" Salmon are five years old and there should therefore be a "filling in" of poor years by fish of different ages from other spawning years- 1.2 fish are four years old and 3.2 fish are six years old.
- A mere 300 m3 sec volume of water recorded in January at Hawick Gauging station 2005, the 2nd highest recorded flood event in any month since records started in 1961 Where does that fit flood exceedance? S0 S1+ 0 0 0 1 4.141499 2.06906975 2 34.37168 8.850251 3 101.1603 21.049795 4 706.7055 134.9693 It is interesting to note that we have a number of very large floods through December and January in 2015. Will this affect Salmon productivity? The complicating factor is that there may have been less spawning due to less fish last year
- 2010 genetic samples taken on lower Gala Water Show site locations on map?
- The ‘smoking gun’ The peak flow of 78.24 m3 sec-1 on the 5th of April was the highest maximum daily flow in that month since records started in 1964. A similar event of 74.12 m3 sec-1 was recorded in 2000, but it is not known whether this occurred at the beginning or end of this month, which could be of critical importance to survival rates of Alevins or recently emerged Fry. In agreement with the literature .g. The functional relationship between peak spring floods and survival and growth of juvenile Atlantic Salmon (Salmo salar) and Brown Trout (Salmo trutta) A. J. JENSEN and B. O. JOHNSEN Norwegian Institute for Nature Research, Tungasletta 2, N-7485 Trondheim, Norway
- Fish counters