Final answer:
The statement that larval clams are ectoparasites of fish is false. Biological challenges facing predators and birds in the Great Lakes include human persecution, invasive species, diseases, and toxin bioaccumulation. Sustainable fishing practices are important to prevent the decline of fish populations.
Step-by-step explanation:
The statement that larval clams are ectoparasites of fish is not true. While there are many organisms that can be parasitic, affecting both invertebrates and vertebrates, larval clams are not typically parasitic in nature. The threats mentioned to predatory animals and fish-eating birds in the Great Lakes are human persecution, invasive species like Asian carp, diseases such as botulism, and bioaccumulation of toxins like PCBs. Overexploitation and overfishing have also led to declines in certain fish populations, underscoring the importance of sustainable fishing practices.
Human persecution is a significant issue for predators as they are often targeted for various reasons, which can lead to a decline in their populations. In aquatic ecosystems, bioaccumulation of toxic substances like PCBs in predatory fish is a concern. These toxins not only affect the fish populations but also the birds that feed on these fish, leading to higher concentrations of PCBs in these birds, which can have detrimental health effects.