There are a total of 434 marine species (7 species of turtles, 312 species of seabirds, and 115 species of marine mammals) and of these a total of 89 species (6 species of turtles, 51 species of seabirds, and 32 species of marine mammals) show entanglement records while a total of 143 species (6 species of turtles, 111 species of seabirds, and 26 species of marine mammals) show ingestion records.

a. Of the 312 species of seabirds, 51 species or 16% had entanglement records. Further, of the five groups of seabirds, the two groups with the highest rate of entanglements are the penguins with 6 of 16 or 38% of species showing entanglement records and the pelicans and cormorants with 11 of 51 or 22% of species showing entanglement records.

b. Of the 312 species of seabirds, 111 species or 36% have ingestion records. Further, of the five groups of seabirds, the two groups with the highest rate of ingestions are the albatrosses with 62 of 99 or 63% of species showing ingestion records and the gulls and terns with 40 of 122 or 33% of species showing ingestion records.

a. Of the 115 species of marine mammals, 32 species or 28% have entanglement records. Further, of the six groups of marine mammals, the two groups with the highest rate of entanglements are the sea otter with 1 of 1 or 100% of species showing entanglement records and fur seals and sea lions with 11 of 14 or 79% of species showing entanglement records.

b. Of the 115 species of marine mammals, 26 species or 23% have ingestion records. Further, of the six groups of marine mammals, the two groups with the highest rate of ingestions are the toothed whales with 21 of 65 or 32% of species showing ingestion records and manatees and dugongs with 1 of 4 or 25% of species showing ingestion records.

a. Based on the data, sea turtles are likely most affected by entanglements. Of the 7 species of sea turtles, 6 (or 86%) have documented evidence of entanglements — the highest rate among the three groups. This is a concern as most species of sea turtles are threatened or endangered. Also, as they range widely over the open ocean it makes it more likely that sea turtles will encounter and get entangled in abandoned fishing equipment.

b. The entanglement problem is hard to quantify as the reported data are based on individuals who are found (typically on the shore) and does not account for animals that die and remain at sea.

In all likelihood, differences in rates of ingesting plastic relate to the feeding ecology of a species. In some cases species eat plastic because they confuse the debris for food: plastic bags can look a lot like jellyfish, while small floating bits of plastic can be mistaken for plankton. In other cases the ingestion is accidental if the plastic just happens to be located in the same space where the animals feed. Also the plastic may be present in the gut of the prey they are feeding on, or their food sources may be attached to the plastic (e.g., fish eggs).

Many questions arise related to the ingestion of plastics and how it impacts species — here are three. Do micro plastic particles cause blockages in the digestive system leading to starvation? Does the plastic debris contain toxins and do these toxins migrate into the tissues and organs of the animals that ingest them? Do buoyant plastic particles ingested by deep sea species negatively impact their ability to return to lower depths?

To study if micro plastic particles cause blockages in the digestive leading to starvation, the gut content of dead marine animals can be studied for amount of plastic ingested and the way it is lodged in the digestive tract, and correlated to the overall nutritional status of that animal — i.e., was the animal starving or malnourished.

To study if plastic debris contains toxins and if these toxins migrate into the tissues and organs of the animals that ingest them, plastic debris can be analyzed for presence of toxins and be tested in various conditions that mimic ocean conditions, or the conditions inside the digestive tract of a marine animal, to see if the pollutants can dissociate from the plastic. In addition, tissue of dead marine animals from the same area, with and without ingested plastic, can be analyzed for the levels of various toxins.

To study if buoyant plastic particles ingested by deep sea species negatively impact their ability to return to lower depths, deep sea species of fish can be fed buoyant plastic particles and tested to see if their ability to move to lower depths is affected.