SUMMARY
Introduced perch negatively impact native fish populations by both competing with juvenile salmon for food, and by directly eating juvenile salmon. The purpose of this proposed research is to develop methods to control the spread of yellow perch into interior lakes and streams, most notably Adams and Shuswap Lakes. Research into the ecology and control methods for perch will be undertaken by an M.Sc. student at Thompson Rivers University.
DESCRIPTION
Over the last several years, Aquatic Invasive Species (AIS), namely spiny ray fish species, have become a major threat in the Thompson/Shuswap drainage area. Spiny Ray fish (perch, small and largemouth bass) have the potential to seriously disrupt and/or limit the capacity of aquatic ecosystems to support socially and economically important native fish species such as Pacific salmon. Yellow Perch (Perca flavescens) have been captured in Adams Lake, presumably moving downstream from Forest Lake via natural dispersal corridors (Sinmax Creek). Unconfirmed reports also place perch in Shuswap Lake in the Salmon Arm area. Their presence in these important salmon and trout habitats place at risk the sustainability of natural productivity and the integrity of the aquatic ecosystems and the economies they support.
Introduced perch negatively impact native fish populations by both competing with juvenile salmon for food, and by directly eating juvenile salmon. The purpose of this proposed research is to develop methods to control the spread of yellow perch into interior lakes and streams.
Larval perch (6 mm) feed primarily on zooplankton, covering a wide size range, depending on the lake (Siefert 1972; Kelso and Ward 1977, Bonar et al. 2005, Brown et al. 2009). As perch grow larger their diet shifts from zooplankton to amphipods, chironomid larvae, other dipteran larvae, and larger aquatic invertebrates (Peterson and Martin-Robichaud 1982, Krieger et al. 1983, Brown et al. 2009). As an adult the diet still includes aquatic invertebrates, but also includes fish eggs and juvenile fish.
Perch are known to lay eggs in large ribbons attached to bottom substrates such as sand, gravel, rubble and vegetation, with the preferred substrates being submerged terrestrial plants (tree and shrub branches in the water), sunken logs, roots and other woody material, and aquatic macrophytes (Craig 1987, Mangan 2004, Brown et al. 2009). The depth of spawning may be influenced by the amount of Dissolved Organic Carbon (DOC) in the water, as this screens out the harmful effects of UV radiation on the eggs (Williamson et al. 1997). The extent of Perch movements around lakes varies, and may be related to lake basin complexity, and season (Radabaugh et al. 2010).
Our current understanding of yellow perch biology is based on studies in other parts of Canada and the United States; we know almost nothing about how perch eat, where and how they spawn, and their preferred habitats in the BC interior. We do know that perch in Forest Lake fed on benthic invertebrates, apparently excluding rainbow trout, which fed extensively on terrestrial invertebrates such as ants and grasshoppers (Bruno and Heise, in prep.). As well, Heise (unpublished) found 14 juvenile fish in the stomach of one perch caught in Adams Lake in 2009, indicating their large potential for negatively affecting larval salmon via predation. Research into the ecology and control methods for perch will be undertaken by an M.Sc. student at Thompson Rivers University (TRU), supervised by Dr. Brian Heise. This is a collaborative project with partners Department of Fisheries and Oceans Canada (stock assessment, habitat, and resource management sections), CN Rail, the BC Ministry of Natural Resource Operations, the Secwepemc Fisheries Commission, and Thompson Rivers University (Dept. Natural Resource Sciences). With the support of the Fraser Salmon and Watershed Program as an industrial partner, we will also have NSERC as a contributor to the project (grad student industrial scholarship).
Literature Cited
Bonar, S.A., Bolding, B.D., Divens, M., and Meyer, W. 2005. Effects of introduced fishes on wild juvenile
coho salmon in three shallow Pacific Northwest lakes. Trans. Am. Fish. Soc. 134: 641-652.
Brown, T.G., Runciman, B., Bradford, M.J., and Pollard, S. 2009. A biological synopsis of yellow perch
(Perca flavescens). Can. Manuscr. Rep. Fish. Aquat. Sci. 2883: v + 28 p.
Craig, J. 1987. The Biology of Perch and Related Fishes. Portland, OR: Timber Press. 333p.
Kelso, J.R., and Ward, F.J. 1977. Unexploited percid populations of West Blue Lake, Manitoba, and their
interactions. J. Fish. Res. Board Can. 34: 1655-1669.
Krieger, D.A., Terrell, J.W., and Nelson, P.C. 1983. Habitat suitability information: Yellow perch. U.S. Fish
Wildl. Serv. FWS/OBS-83/10.55. 37p.
Mangan, M.T. 2004. Yellow perch production and harvest strategies for semi-permanent wetlands in
Eastern South Dakota. MSc thesis, Wildlife and Fisheries Sciences, South Dakota University. 85p.
Peterson, R.H., and Martin-Robichaud, D.J. 1982. Food habits of fishes in ten New Brunswick lakes. Can.
Tech. Rep. Fish. Aquat. Sci. 1094: 43p.
Radabaugh, Nicholas B., Bauer, William F. and Brown, Michael L. 2010. A Comparison of Seasonal
Movement Patterns of Yellow Perch in Simple and Complex Lake Basins, N. Am. Jour. of Fish. Manag., 30:179-190.
Siefert, R.E. 1972. Fish food of larval yellow perch, white suckers, emerald shiner, and rainbow smelt.
Trans. Am. Fish. Soc. 101: 219-225.
Williamson, C. E., S. L. Metzgar, P. A. Lovera & R. E. Moeller. 1997. Solar ultraviolet radiation and the spawning habitat of yellow perch, Perca flavescens. Ecol. Appl. 7: 1017-1023.
OBJECTIVES
Determine distribution and feeding ecology of yellow perch in Pinaus and Swan Lakes (spring, summer and fall). Do additional sampling of perch diet in Wood, Ellison, Kalamalka and Little Pinaus Lakes.
Determine food availability in Pinaus and Swan Lakes through sampling zooplankton and benthic inverts. (spring, summer and fall). Complete additional sampling on Wood, Ellison, Kalamalka and Little Pinaus Lakes.
Determine the timing of yellow perch spawning in Pinaus and Swan Lakes in spring 2011 and 2012
Determine if yellow perch in Pinaus and Swan Lakes will spawn on artificial spawning substrates (spring 2011)
Complete trial of artificial spawning substrates in Adams Lake in spring 2012.
METHODS
Component 1: Life History and ecology
The Life history and ecology of introduced perch will be studied intensively in Pinaus and Swan Lakes. Information will be collected on spawning timing, gut contents and feeding ecology, size class structure of the population, and depth (habitat) preferences of the perch. We will determine the time of spawning in the spring by gillnet sampling of perch (for gonad inspection) and snorkelling observation of the shallows of the small lakes to look for spawning behaviour and signs of egg strings. We will also be determining where perch are foraging and what they are eating. This will involve gill netting of perch and trout in the spring, summer and fall in Swan and Pinaus Lakes to examine gut contents for feeding ecology. The fish captured will also be used to determine the size class structure of the perch population. Fish length, weight, sex, and stomach contents will be recorded. Stomach contents will be preserved by injecting alcohol into the stomach of the dead fish. Gill netting will take place once in the spring, summer and fall of 2011 to examine changes in feeding patterns over that time period.
Four other lakes will also be sampled twice during the summer (Wood, Ellison, Kalamalka and Little Pinaus Lakes), as the diet of perch may vary from lake to lake. Brian Heise’s lab at TRU has been examining perch gut contents for the past few years, and so is well equipped to complete the feeding analysis.
Food availability within the lakes during spring, summer and fall will be determined by sampling zooplankton, benthic invertebrates and small fish present in the lakes. This sampling will take place in conjunction with the gill net sampling of the perch and rainbow trout so that stomach contents can be compared to the food sources present at the time. Sampling of benthic invertebrates will be completed in the shallows by sweeping a D-frame net for 30 seconds, and in deeper water using an Ekman grab sampler. Zooplankton will be sampled using a Wisconsin plankton net. Small fish will be sampled in the shallows of the lakes using a baited Gee trap.
Radio transmitters will be implanted into a small number of perch (2 lakes x 2 sets x 6 perch per set = 24 fish) in order to follow their movement patterns and depth/temperature preferences in Pinaus and Swan Lakes. Transmitters will operate in June/July transmitting data 24 hours a day, allowing us to track day/night changes in activity. A separate sample of fish will have transmitters implanted for the period July-November, but in this case the transmitters will broadcast for only 12 hours a day (during the day), thereby lasting longer (less drain on their batteries). The transmitters in fish in Pinaus Lake will transmit location and temperature; by recording a temperature depth profile of this lake during the study, we will be able to calculate the depth of the fish based on its temperature (because fish are cold blooded, their body temperature will give us the temperature of the water in which they are swimming). Temperature/oxygen profiles will be taken using a YSI meter. Temperature sensors will not be used in Swan Lake, as this lake is very shallow, and so will show little temperature difference from top to bottom; however, we will still be tracking fish movements through radio transmitters. The transmitters to be used are:
Lotek MST-820-T, 8 mm x 22 mm, weight 2.2 grams (temperature sensor)
Lotek MST 820, 8 mm x 20 mm, weight 2.1 grams (location transmitter)
Fish will be caught by angling and held in a holding area. Just prior to surgery the fish will be anaesthetised using MS-222. The surgery will take place with the fish sitting upside down in a V-shaped trough containing enough water to keep the gills wet, but the belly dry. A small incision will be made in the belly of the fish, the transmitter implanted, and the incision sewn up. The whole procedure should take ~ 2-3 minutes, given the small size of the transmitters.
Component 2: Control of perch using artificial spawning substrates
Perch are known to lay eggs in large ribbons attached to bottom substrates. We will identify suitable shallow areas at Pinaus and Swan Lakes for placement of artificial spawning substrates. We will use two types of artificial substrates: 4 substrates constructed from lumber, with dowels simulating submerged trees, and 4 substrates constructed from sections of seine netting. We believe that our wooden structures will work based on the use of bundles of brushwood to collect eggs of European perch (Pedicillo et al. 2008). We will also “bait” the artificial spawning substrates with perch female pheromones if we can find a supplier (we have contacted Dr. Michael Stewart, Marine Natural Products Chemist, National Institute of Water & Atmospheric Research Ltd (NIWA) in Hamilton, New Zealand, who has worked with Perca fluviatilus). Once the artificial substrates are colonized with eggs the substrates and eggs will be removed from the lake, killing all eggs. We will develop this technique in the spring in Pinaus and Swan Lakes; if time allows we will then also try it in one of the shallow bays in Adams Lake (near Bush Creek Park, or in Agate Bay), where the availability of natural spawning substrates is limited.
Literature cited:
Pedicillo, P., F. Merulli, A. Carosi, P. Viali, and M. Lorenzoni. 2008. The use of artificial spawning substrates as media to support the reproduction of Eurasian perch in Lake Piediluco. Hydrobiologia 609:219-223.
BENEFITS
This project will directly contribute to the long-term sustainability of Fraser Basin Pacific salmon by developing a method to control the spread of invasive yellow perch. Invasive perch negatively impact native salmon populations by both competing with juvenile salmon for food, and by directly eating juvenile salmon. This research will develop methods to control the spread of yellow perch into interior lakes and streams by reducing perch spawning success in large lakes where eradication techniques such as rotenone treatment are not feasible. This project will also develop new partnerships among Thompson Rivers University, two government agencies responsible for fish, CN Rail, and First Nations. Further, capacity building will be provided in terms of both skills and leadership with the training of one masters and one undergraduate student, and the engagement of public fishers at the study lakes.
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