On May 7th, our guest speaker was Steve Hogler, a fisheries biologist with the WI DNR. Steve has worked for the DNR for quite a long time, and his work focuses on Green Bay Fish Management. He manages the waters of Manitowoc, Kewaunee, Brown County & Door County tributaries, and lakes & waters of Green Bay, both inland and offshore areas. He is also a large part of the Green Bay walleye and muskellunge assessments and management practices. Some of the management issues Steve is faced with and working to improve include: habitat destruction and loss, water pollution, unregulated fishing practices and invasive species management.
A main focus of management is restoration of fisheries, specifically native fish. This involves stocking and habitat restoration and creation. In regards to walleye populations, they were stocking millions of walleye fry and fingerlings about four decades ago. Within 10-15 years, the populations had started reproducing naturally, and so they stopped the stocking efforts. The DNR also creates spawning reefs for walleye, and this has proved to be a very successful method is maintaining their populations. To monitor walleye, they do spring and fall YOY assessments, spring tagging of spawning adults in Fox River and tributaries, and creel surveys at relevant fishing locations. They recently started a floy tagging program to help determine if walleye return to the same rivers to spawn, as well as see where they go between spawning periods.
The spotted musky management and monitoring program is quite similar. The DNR does spring netting to embed a PIT tag, as well as collect eggs and milt for hatchery rearing. They also do spring and fall electroshocking and take creel surveys.
From a broader aspect, there are over 60 species of fish in the Fox River. This is a great sign of improvement, yet there is still a ways to go in terms of water quality and habitat availability for these fishes.
On April 16th, Patrick Robinson came in to talk with us about his career history and what he does now with the UW-Extension. Patrick has worked as a consultant ecologist, a natural resources educator, and as a regional ecologist. He really wanted to get back to the university, so he started working for the UW-Extension office as their environmental restoration and estuary outreach coordinator. He is now working on the Lake Superior National Estuarine Research Reserve and is also an adjunct faculty member at UWGB.
As an employee of the Lake Superior NERR, he was in charge of designating a piece of land for permanent protection that would get funding every year for research and education. Patrick chose the St. Louis River freshwater estuary. He needed to then go out and make sure the community was okay with the plan and inform everyone of the changes taking place. A lot of research and monitoring went into this decision, and there are now numerous resources for scientists and the public alike to take part in the research reserve.
The UW-Extension has staff all over the state, and they have a lot of resources as well. One of the bigger projects Patrick is working on is the Cat Island Chain Restoration project. The Cat Islands were wiped out by a large storm in the 1970s, and this caused a huge decline in vegetation and aquatic species that inhabited the lower bay of Green Bay. After 40 years of planning, the restoration project began in 2012 when the island outlines were built with riprap, and were filled in with dredge material. A few graduate students at UWGB are doing research in regards to the island chain. The research is focused on vegetation, water quality, and migratory bird use. One of the main goals is to construct a successfully self-monitoring seed bank to kickstart vegetation growth around the islands. Since this project is so massive and still fairly new, there is a heavy need for more research.
This past Thursday, Nick Legler, a DNR Great Lakes Fisheries Management Biologist, came in to talk with us about Chinook salmon management in Lake Michigan. Chinook salmon are not native to the Great Lakes, but once the alewife population skyrocketed, different trout and salmon species were brought in to control them. Chinook and alewife are both pelagic feeders, and therefore Chinook did the best in controlling alewife populations. This worked great for a while, but now there are too many predator fish and not enough prey, which causes a lack of nutrition for the salmon.
Many forage surveys were completed, and results show that overall forage biomass is very low – the alewives aren’t reaching their typical size, and the salmon are consuming them at a younger age than normal (1-3 years). This proves to be more energetically costly for the salmon. Since quagga and zebra mussels have moved in, they have removed a lot of the smaller organisms that larval alewife usually eat, causing food shortages for them. This factor, along with the large number of Chinook salmon in the lake, is causing a top-down bottom-up effect and putting too much pressure on the alewife to survive.
Chinook salmon are currently raised in a number of hatcheries in the state that prove to be successful. However, reduced stocking of these fish may be needed in order to get the alewife population back up. It would be pointless to stock even more Chinook salmon, because without a main food source, they would not have a high survival rate.
On Thursday, March 26th, Kevin Mann came in to talk with us about Lake Sturgeon Streamside Rearing operations. Kevin is a fish biologist with the US Fish & Wildlife Service, and he works out of the Green Bay Fish and Wildlife Conservation Office.
Lake sturgeon are a very long-lived species and don’t mature until they are ~ 12-20 years old. Because of this factor, their populations do not increase too rapidly. Therefore, outside factors have a highly negative effect on them. Pollution, dam blockage and overfishing have all led to the extirpation of many populations. Some agreed upon solutions include: create fishing restrictions/closures, keep water flow relatively constant below dams, and regulate river pollution. Another big way to have a strong positive affect is to engage in streamside rearing.
Streamside rearing is done from a mobile trailer that ‘raises’ the sturgeon within the water of the river they will likely return to. Lake sturgeon are a species of fish that use natal homing to return to the river they were raised in to spawn, so this is a crucial part of the process. Before the water enters the tank, it is filtered to remove sediment and then UV treated to removed bacteria. This is done to protect the fish from starvation and disease. To obtain the gametes needed for reproduction, there are two methods. For populations being re-established, they take eggs and sperm from the fish. For populations that are being supplemented, they use ‘egg mats’ that collect the eggs, and bring those into the facility to raise. They also collect larval sturgeon during drift periods. Once the fish reach a size of 6-10 inches, they are tagged – either with a coded wire tage or PIT tag – and released.
On Thursday, March 12th, we had Tim Strakosh in from the US Fish and Wildlife Service to talk with us about their multi-state Lake Michigan Aquatic Invasive Species Early Detection Monitoring Program. Aquatic invasive species have huge ecological and economical impacts wherever they are prevalent. Loss of biodiversity, negative alterations to ecosystem functions, and increased climate change impacts are just a few, not to mention nearly $5.6 billion/year loss in commercial fisheries and $4.5 billion/year loss in sport fisheries in the Great Lakes area. The best resolution is to stop the invasives at the source of entry by first eliminating the inlet channels, then practicing early detection methods, and finally monitoring the ecosystem as a whole.
2014 was the first year this program was fully implemented. The success of the program largely depends on rapid communication with all partners involved, research, and constant outreach and education to the public. Tim is currently working on a risk assessment model to narrow the program and hopefully become more efficient.
Another large part of the AIS program is the e DNA surveillance, currently focused on bighead and silver carp populations. In 2013, there were 1,600 e DNA sample collected in the Great Lakes. By the following year, 2,150 samples were taken just from Lake Michigan, with 4,262 overall. Environmental DNA can be transferred through different vectors, like bird poop or barge ballast water, so that can give false positives. In these cases, extensive sampling would be done over multiple days to ensure the reading.
The AIS program also focuses on macro invertebrate sampling to screen for new mussels and/or amphipods, ichthyoplankton sampling, and nearshore sampling using traditional gear.