The data in the following table come from a report by Greenpeace based on research published on plastic debris in the world’s oceans between 1990 and 2005.
INTERPRETATION
How many different species are included in these data and how many are affected?
For seabirds:
What percentage of seabird species had entanglement records? Which two groups had the highest rate of entanglements?
What percentage of seabird species had ingestion records? Which two groups of seabirds had the highest rate of ingestions?
For marine mammals:
What percentage of marine mammal species had entanglement records? Which two groups had the highest rate of entanglements?
What percentage of marine mammal species had ingestion records? Which two groups had the highest rate of ingestions?
|
Species group |
Total number of species worldwide |
Number and percentage of species with entanglement records |
Number and percentage of species with ingestion records |
|---|---|---|---|
| Sea turtles | 7 | 6 (86%) | 6 (86%) |
| Seabirds | 312 | 51 (16%) | 111 (36%) |
| Penguins | 16 | 6 (38%) | 1 (6%) |
| Grebes | 19 | 2 (10%) | 0 |
| Albatrosses | 99 | 10 (10%) | 62 (63%) |
| Pelicans and cormorants | 51 | 11 (22%) | 8 (16%) |
| Gulls and terns | 122 | 22 (18%) | 40 (33%) |
| Marine mammals | 115 | 32 (28%) | 26 (23%) |
| Baleen whales | 10 | 6 (60%) | 2 (20%) |
| Toothed whales | 65 | 5 (8%) | 21 (32%) |
| Fur seals and sea lions | 14 | 11 (79%) | 1 (7%) |
| True seals | 19 | 8 (42%) | 1 (5%) |
| Manatees and dugongs | 4 | 1 (25%) | 1 (25%) |
| Sea otters | 1 | 1 (100%) | 0 |
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ADVANCE YOUR THINKING
Hint: Access the actual report at http://bit.ly/tdQ7Kr.
Scientists suspect that entanglement is a significant cause of population decline for many species, but they consider the reported entanglement rates to be conservative.
Based on the data in the table, which group (sea turtles, seabirds, or marine mammals) is likely to be most affected by entanglement? Why?
Why might reported entanglement rates underestimate the real problem?
Ingestion refers to animals eating plastic. While many species of marine mammals, seabirds, and sea turtles ingest plastic, some groups ingest more than others. What might explain these differences in ingestion rates among species?
Not much is known about the specific consequences of aquatic species ingesting plastics. In the process of science, observation leads to more questions. List three questions about ingestion of plastics that should be studied. How would you go about answering one of these questions?