Great Lakes, Great Stakes! Part 1. The rise and fall of fish species.

10 05 2011

Are the Great Lakes important? Should people outside of the region care about our Great Lakes?  The Institutes for Journalism and Natural Resources (IJNR) think so.

Last week, a group of American and Canadian journalists travelled around Lake Ontario on an IJNR fellowship.  Travelling on a bus rented from a Montreal hockey team, they started their journey canoeing down the Don River in Toronto. After the canoe trip, they continued along their route, stopping at various sites to meet experts and learn about environmental issues affecting Lake Ontario.

Frank Allen of IJNR invited me to join them halfway through their trip.  I met the journalists in Sackets Harbor in New York and spent a lovely evening talking about science communication and the journalist perspective.  The next day, inspired and energized by the discussions from the night before, I joined several journalists on a charter fishing boat captained by “Megabite”.  The goal for the day was to land some trout, but the heavens opened early.

IJNR Fellows fishing in the rain

IJNR Fellows fishing in the rain

Despite the downpour, it was a good trip. We went to a deep trench in Lake Ontario by an island where trout and salmon congregate at their preferred cold temperatures and caught many fish.  And throughout the day we talked extensively about the science and economics of the introduced fish.

IJNR fellows interviewing Captain "Megabite"

IJNR fellows interviewing Captain "Megabite"

Most trout and all salmon in Lake Ontario are not native. They have been stocked by state and provincial governments for several decades.  They are the cornerstone of a thriving multi-million dollar sportfish and recreational fishing industry around the lake.

Just as I wrote about Lake Erie, Lake Ontario is not the same lake it was 50 years ago.  Invasive species, especially round goby, now make up a high proportion of the trout and salmon diets. After meeting with the charter boat captains and New York biologists we discussed native, introduced and invasive species. The Sackets Harbor captains mentioned that the round goby had very probably revived their fishing businesses in a big way!

Trout caught by IJNR fellows for lunch!

We then drove over the Canadian border to meet with a group of people working on the endangered American eel.  The rain simply would not abate, and we had to huddle under a bridge by small river for shelter. This particular river is an important site for young eels and we were to see a demonstration of electro-fishing. My colleague, John Casselman and his graduate students spoke about their work with American eel, which has an amazingly intricate marine-freshwater lifecycle that is threatened by dams along the St. Lawrence Seaway.

In addition, John Rorabeck, an expert commercial fisherman, spoke about the historical importance of American eel to fishing industries. Unfortunately the boat was not working so we could not collect American eel, but the journalists got to listen to top-notch stories by two leading experts.  It was wonderful to listen to John R, especially as he truly has close ties to Lake Ontario and he had worked with one of my graduate students on the Rideau Lakes catching fish for our food web analyses.

Commercial fisherman John R speaking about American eel

Commercial fisherman John R speaking about American eel

By the end of the day the complexity of the lake was becoming very apparent. We had considered introduced fish species which were benefiting from an invasive fish species, the trout and the round goby. We also discussed a native species fast declining in the Great Lakes.  Lake Ontario is changing very rapidly… what will it be like in the future? Even the most knowledgeable scientists and fishermen are not sure.

Tomorrow:  Tilting at wind turbines.


Project 52 No 18. Fishing for fun? Then take care of the fish!

15 02 2011

¡Hola de Bariloche! While I doubt very much we’d get the opportunity to sample Nahuelito, the local monster, we did get a pretty good representation of key species from the entire food web in each of the 3 sites in Lake Nahuel Huapi over the past two weeks. Last Thursday and Friday, we sampled the third and final site, the southernmost bay near Dina Huapi and the Rio Limay, a famous trout river.   Nahuel Huapi National Park is renowned internationally for its trout fishing, with all of its trout species introduced since early 1900’s until about 1950-60’s.  Now, all trout species are self-sustaining and provide very important economic revenue for the region.

While we were searching for a place on the Dina Huapi beach to put the boat in, I came across this dead trout, likely a rainbow trout (Oncorhynchus mykiss), although I couldn’t confirm the identification.  Within the Park boundaries, anglers are not permitted to keep the fish they catch, but must release all fish.  The cause of death for this trout is likely exhaustion and poor handling after capture.

This image reveals the other side of trophy and sport fishing – fish do suffer and do not always recover rapidly from being caught especially if there is a long fight on the line and a tricky hook to take out.   I liked this image as it contrasted textures and colours of the pale decaying trout against the beautiful  cobblestones under the water in the very harsh morning light.  As such, the presence of death  in such hard surroundings sends a powerful message. 

Exhausted trout near Limay River

I am not against recreational fishing.  However, it is good to be reminded that all actions we undertake will have consequences, and it is always wise to minimize the negative impacts of those acts when we can.

Here is a shot of the nearby river and the Park signage:

Fly fishing in Nahual Huapi

Ecogirl: Tomorrow’s Lake Erie is not yesterday’s.

10 06 2010

Slipping on the metal deck, I step back quickly as the motorized reel hauls the fish net onto the Ontario Ministry of Natural Resources boat. Early-morning breath mists the air; gloved hands reach for frantic fish trapped in the net as it is being pulled onto the boat. We eye each fish as it is tossed into a plastic bin filled with ice. Scales are everywhere, sparkling like sequins.

Bin after bin is filled as we continue with the survey along the Lake Erie shoreline. Excitement increases a notch when a metre-long brown trout is added to the bin, but work must continue as the net full of fish is still being pulled onto the boat.

From this first sight, it seems apparent that the lake is full of healthy fish, and all is well. But science says not so. The fish of Lake Erie have changed dramatically, and there is cause for concern for the future.

In the bins, we can see numerous slimy brown fish with bulging eyes
Round Gobywriggling across the crushed ice, each about a hands’ length. Those round gobies are the descendants of a handful transported from across the Atlantic Ocean just 15 years ago. Today, the Lake Erie round goby population is now in the billions.

The round goby is not the only unwanted immigrant to Lake Erie. Its fellow European hitchhikers, zebra and quagga mussels have spread throughout North America since their introduction in the early 1980s. Even now, scientists are wrangling with exponential increases of another European introduction, the tiny bloody-red Hemimysis shrimp, discovered in Lake Erie only a few years ago. Those unwanted invaders are out-competing many native species and are changing the food web dynamics by altering prey-predator relationships.

The costs due to impacts of invasive species are high. In 2008, researchers at the University of Notre Dame, Center for Aquatic Conservation, estimated that invasive species cost around $200 million US dollars a year in losses to commercial and sport fishing, loss of habitat and impaired access to the area’s water supply.

With the addition of new exotic species nearly every year, many seem to think that nothing can disturb the huge commercial walleye and yellow perch fishery, among the largest in the world. However, those fisheries are in steady decline for a while. The disappearance of the blue pike, a close cousin of the walleye, serves as a cautionary tale.

The native blue pike was a tasty expensive treat eaten by restaurant patrons along the Lake Erie shorelines until the 1960s. Due to overfishing and possibly due to increased contaminant exposure, anglers found they no longer were catching blue pike in Lake Erie or elsewhere. Ten years ago, Carol Stepien, a University of Toledo fish geneticist, reported at a meeting that a 37-year frozen specimen was merely a blue pike – walleye hybrid. This confirmed that there couldn’t be any blue pike in the lake. Whispered rumours and pickled specimens in dusty museum jars are the only clues that those commercially valuable fish species ever existed.

Those shifts were why we were excited to catch a prize brown trout this morning. Many of us did not realize that such a magnificent specimen is the direct result of stocking programs. Desirable species have been replaced and supplemented many times over. For example, lake trout nearly disappeared from the lake in the 1940s due to over fishing and other factors. However, through government efforts, the lake trout and its salmonid cousins has been re-stocked every few years, ensuring that a few trophy sportfish will be caught every year by lucky anglers, and the occasional scientist.

The Natural Resources ship returns to its Port Dover dock after a long day ofProcessing fish in the OMNR fish lab at Port Dover collecting fish. We carry the cold bins full of fish back to the laboratory. The next day, the fish will be carefully weighed, processed and counted. Many fish will go into a freezer for genetic and chemical analyses which will eventually provide insights into the complex dynamics in the lake, including the invasions, stocking and disappearances of many species.

This survey is not the first one. Ontario Ministry of Natural Resources has been conducting similar surveys for the last 30 years. All this work has allowed Natural Resources scientist to build an immensely valuable database on fish and environmental conditions. The database allows us to determine changes in fish communities through time along Lake Erie’s shorelines and see if there are links with ongoing environmental changes. We can say with absolute confidence that the Lake Erie we see today is just not the same lake that existed 40 years ago.

Added: Link to scientific paper.

LM Campbell, R Thacker, D Barton, DCG Muir, D Greenwood && RE Hecky. 2009. Re-engineering the eastern Lake Erie littoral food web: The trophic function of non-indigenous Ponto-Caspian species. Journal of Great Lakes Research 35(2): 224–231.