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Hook, Line and Sinkered into a Sea of Garbage

August 5, 2011

Category: A Closer Look

From ocean pollution to overfishing, human impacts have caused dramatic changes in coastal and marine ecosystems worldwide.

The toxic chemicals from oil spills or sewage disposal, slowly decomposing garbage and fishing gear left in the ocean are often the causes of sickness, injury and death to marine animals. Most of the waste humans produce on land eventually reaches the oceans, either through deliberate dumping or from run-off through rivers and drains. In fact, over 80 percent of marine pollution comes from land-based activities.

Since its establishment in 1966, the Moss Landing Marine Laboratories (MLML) has executed in-depth marine science research and given students pursuing their Masters of Science degrees the hands-on education needed to excel in marine topics such as marine life decline.

Operated by a consortium of seven California State University campuses (East Bay, Fresno, Monterey Bay, Sacramento, San Francisco, San José and Stanislaus), the MLML works with scientific collaborators to examine the effects of human behavior on the marine environment.

Recently, the MLML has collaborated with the Marine Mammal Center to examine the health, disease, contaminant levels and post-release survival of harbor seals along the west coast including Tomales Bay, San Francisco Bay and Monterey Bay. Through projects such as determining the levels of emerging contaminants in free-ranging harbor seals, MLML students and faculty were able to determine that persistent organic pollutants are associated with disease susceptibility and decreased immunity in marine mammals.

Similarly, the MLML has conducted numerous studies that have examined changes in demography and life history of individual species as a result of fishing. Scott Hamilton, assistant professor in Ichthyology at Moss Landing Marine Laboratories and San José State, has been focusing his research on the ecology of coastal marine fish and how the presence of top predators affects the health of coral reef ecosystems.

With student assistance in field and lab work, data analysis and research, Hamilton and his colleagues discovered that islands with people had fewer sharks and large fishes, lower coral cover, higher fleshy macroalgae cover and more pathogenic microbes in the water. Additionally, they found that on unfished islands large predatory fishes were able to live longer and grow larger.

The loss of large predators from an ecosystem triggers an ecological phenomenon known as a “trophic cascade” — a chain of effects moving down through lower levels of the food chain — and changes the structure and dynamics of the ecosystem.  Their decline, largely caused by humans through hunting and habitat fragmentation, has had dire consequences, including changes in vegetation, infectious diseases, wildfire frequency, water quality, invasive species and nutrient cycles.

“Many of the declines we are seeing from overfishing and climate change to pollution and invasive species involve anthropogenic disturbance so solutions will require humans to change their behavior,” said Hamilton.

Professor Hamilton’s research is just one of the many projects underway at the MLML.

In addition to a dedicated team of faculty, staff, students and researchers, MLML’s state-of-the-art equipment and prime location near ample marine resources places the CSU at the frontiers of marine science where discoveries are being made.

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