A picture of a sea turtle tangled up in a mile-long fishing net contrasted the image of a white-striped orange clownfish wading in the sea floor’s protective tentacles during Pam Blackledge’s presentation on ocean depletion.

The depletion of fish in oceans and its effects were among the main topics of discussion Wednesday afternoon in the Life Science III Auditorium.

Blackledge, the Great Lakes Regional organizer of Conserve Our Ocean Legacy campaign, spoke about the various dangers oceans and their marine life face due to “overfishing” practices.

The presentation comes at the heel of a recent study released by the PEW Charitable Trust “America’s Living Oceans.” The report cited sport and commercial fishing, pollution, global warming and overfishing as contributing factors to the ocean’s risk of losing valuable resources.

In mid-April, the U.S. Commission on Ocean Policy will release a report on the issue following the PEW study.

Blackledge focused her presentation, which was sponsored by the SIUC student chapter of the American Fisheries Society, on overfishing. Overfishing means severely depleting fish stocks at a rate that outpaces the time it takes for the population to renew itself naturally.

Harmful fishing practices, which include the use of bottom trollers and fishing fleets and cast massive nets that span miles, are mostly utilized by commercial fishing corporations, Blackledge said. She said the common use of these ships contributes to unnecessary and excessive destruction of fish, which affects other marine life. The net’s wide reach collects unwanted marine creatures and plants that end up “rotting on the boat deck.”

“It goes beyond just fish,” Blackledge said. “It goes looking at the ocean as an entire ecosystem, looking at fish populations but also looking at habitat and looking at how species interact with other species.”

In addition to harmful fishing practices, the presentation encouraged students to educate themselves about how the government regulates the fishing industry. The campaign aims to point out conflicts of interest that may be hindering the use of environmentally unsound fishing methods.

“The idea is to have someone based in the Midwest to talk more about ocean issues inland, to gain more support so that when it comes to vote in Congress for stronger ocean protections that our Midwest legislators will have the information and the support behind them to actually vocal on ocean protection issues,” Blackledge said.

In 1996 Sustainable Fisheries Act, renamed the Magnuson-Stevens Act, enforced the reduction of overfishing and protection of specified ocean areas. Blackledge said regulation still has been lax in recent years.

The campaigns cited recent reports from the National Marine Fisheries Service, including a 2002 finding that “about 60 percent of commercially important stocks is severely depleted by overfishing.”

Bruce Tetzlaff, research project director of SIUC’s Fisheries and Illinois Acquaculture Center, said any ocean issue has direct effects on landlocked geographic locations such as Carbondale.

“In the Midwest, some of the environmental things that affect the ocean fisheries, such as nutrients flowing down the river into the oceans creating deadzones and eliminating habitat for ocean fishers, affect us very importantly,” he said. “Whether it be the over-fertilization of farm fields or the improper fertilization of farm fields or wetland destruction so that the water rushes down rather than soaks in so there’s a lot of fresh water acquatic things, that directly affects the oceans.”