July 30, 2010
The morning began with an overview lecture on the Great Lakes and Lake Ontario (1) , presented by New York Sea Grant’s (NYSG) Helen Domske. The presentations, which will be made available for use by the teachers in their classrooms, focused on the geology [see illustration in (2)], history and environmental issues of the Great Lakes system, along with an in-depth look at some of the important issues related to Lake Ontario. These include the Cladophora algae problems, issues with increased fishing pressure of the double-crested cormorant, Type-E botulism outbreaks, and changes in the fish community of the Lake caused by the introduction of invasive species. Throughout the week, the educators have learned about some of these issues, so it was a good review of some of their new-found knowledge.
“Did you know that a total of 86% of inflows to Lake Ontario comes from the upper Great Lakes and Lake Erie via the Niagara River?” asked Domske at one point during the lecture. “So, you can see how water quality in Lake Ontario is affected by upstream sources and inputs from local industry, urban development, agriculture and landfills.” As discussed in “Day 3″ of our blog (July 27, 2010), this is what has led to identifying various Areas of Concern (AOCs) in Lake Ontario and throughout the rest of the Great Lakes system (3). Lake Ontario is certainly not stagnant or a complete sink to what enters its system, though. With a retention time of about six years, about 93% of the water in Lake Ontario flows out to the St. Lawrence River, with the remaining 7% leaving via evaporation.
A number of native species in Lake Ontario (4) (5) - whitefish, lake trout, lake herring, Atlantic salmon - have seen population fluctuations over the last century, mostly due to changes in the food web. For example, spring abundance of diatoms, a microscopic algae that is an important food source for zooplankton and opossum shrimp (Mysis), has declined in the Eastern Basin of Lake Ontario since the establishment of zebra and quagga mussels. Any decline in diatoms would affect zooplankton and Mysis, which then impacts forage fish like lake herring and its competitor since at least the 1950s, the invasive alewife. With their food source at risk, lake herring and other native species certainly struggle more to thrive in the presence of pervasive species like the alewife. (See a NYSG Coastlines article spotlighting Sea Grant-funded research on Mysis and alewife to get a better sense of impacts on the Great Lakes food chain, click here.)
Overall, much has changed with Lake Ontario fisheries over the years, as the teachers saw in a presentation timeline:
- Early-late 1800s: canal system, lamprey enter, watershed changes: deforestation, damming, siltation, unregulated salmon fishing, alewives introduced, salmon collapse and extirpated.
- 1920s and 1930s: lamprey predation, highly-prized fish populations collapse, increased harvest on alternative fish species, introduction of smelt and double crested cormorant, smelt and alewife dominate offshore, alewife die-offs, human population growth, industry, nutrient inputs.
- 1950s and 1960s: population collapses of many native species, severe decline of lake trout/burbot, St. Lawrence Seaway, TFM (a chemical carefully applied to streams infested with aquatic invasives such as sea lamprey ton control their populations), massive alewife die-offs, contaminant loading, hydroelectric power use, successful stocking, lamprey control, concern for nutrient loading, cormorants decline.
- 1970s and 1980s: beginning/expansion of stocking efforts, sportfishery generating revenue, alewives and smelt under some control, ballast species introductions, nutrient/toxic abatement, signs of successful lake rehabilitation.
- 1990s and early 2000s: stocking rates/sportfisheries peak & decline, more ballast invasions with negative impacts on fish/ecosystems, cormorant populations explode, alewife/smelt decline, signs of successful lake trout reproduction, fisheries sustainability?
In addition to discussing how recent climate trends have influenced the Great Lakes (6), the teachers detailed some of effects human impacts have had on fish communities in Lake Ontario, the Lake “in their backyard.”
- A shift from dominant species that are large and long-lived (i.e. lake trout, Atlantic salmon, lake sturgeon) to smaller, short-lived fish species.
- A shift in populations with relatively stable populations (numbers and age) to unstable populations fluctuate considerably (numbers/ages).
- A shift from populations with diverse habitat preferences and diverse physical characteristics to populations that thrive only in narrow range of habitats.
- A shift in abundance of highly-prized, commercial fish species for human food to species to fish species that are of little or no commercial value.
Before breaking for lunch, the teachers took part in an interactive three-hour workshop on geospatial mapping that was presented by Cornell University geographer Susan Hoskins, and NYSG educator, Nordica Holochuck [pictured (7) r-l, along with NYSG’s Mary Penney and Dave White]. This workshop was similar to one the pair presented in New York City, but this version focused on Lake Ontario and its sand dune ecosystem. The teachers learned about topographic maps and how to read the map symbols, colors and patterns. They were also shown how to use aerial maps and were asked to complete an exercise that used their newly-learned information to determine information on the sand dune area and changes that have taken place over time. Educators then presented their findings to each other.
During an early afternoon break, the teachers got back into groups they formed earlier in the week (8) and worked on lesson plan materials presented on Friday, July 30, the final day of the workshop. Discussions centered not only on what the teachers learned during their week-long Lake Ontario training, but also how they might implement some of the concepts into their classroom curricula.
In the afternoon, the educators headed to SUNY Oswego’s Rice Creek Field Station for a presentation by Dr. Lucina Hernandez (9), who originally worked on ecosystem issues in Mexico. Dr. Hernandez told the group about some of the research being conducted by students and faculty of the college who utilize the different ecosystems of the station to study the plants and animals found within this beautiful location. Afterwards, a few of the educators shared their week-long experiences so far with a reporter from The Salmon River News (see news article, pdf). They later joined the other teachers for a walk through the trails, where they observed native and invasive species that are found on the grounds of the field station.
The station property is made up of a 26-acre Rice Creek pond (10) surrounded by 300 acres of land in several stages of succession from open field to mature forest. It includes a small nature center where the educators were able to see preserved specimens of many of the birds they have encountered during the workshop. While its primary function is to provide facilities for field-oriented courses in natural science taught at SUNY Oswego, the field station is also available for public education and recreation.
On the way to the next location, NYSG Program Leader Dave White gave an historic and cultural overview of the Oswego Harbor (11) from a beautiful overlook on the harbor (12). While looking out at the lighthouse, U.S. Coast Guard Station and marina, the educators learned about the important role that the Oswego Harbor has played to shape the history and economy of the area.
The last stop of the afternoon was the H. Lee White Marine Museum (13), where the group learned about the history of the area, the importance of shipping and its economic contribution to the growth of Oswego. The educators had the chance to tour the facility and explore a World War II ship that has been added to the museum’s display. During this time, some of the teachers local to the Oswego area reflected on their experiences along Lake Ontario with a reporter from the Palladium Times (14). Overall, the museum experience helped to round out the week and provide the teachers with some historical and cultural perspective on Lake Ontario.