Question

1a. What is the "tragedy of the commons?" Discuss how this relates to examples of over-exploited fisheries?

1b. Describe a marine habitat and describe 2 biotic factors and 2 abiotic factors that affect organisms in that habitat. Describe 2 ecosystem services provided by it as well.

Answer 1

Ans 1a) Tragedy of commons is a situation that arises in a shared-resource ecosystem, where individuals act according to their self interests and benefits, hampering the common benefits of all the users, leading to depletion and exploitation of the shared resources.

One of the best examples of tragedy of commons is over-exploited fisheries.

- In fisheries, the fish, the fishermen and the corporate fishing companies share a common resource ecosystem, water.

-Ideally, the fish use water as their natural habitat while the fishermen use fish as a source of income and maintain an ecological balance by keeping the population of fish in check.

- But due to the self interest and benefits of fishermen and corporate fisheries, over-exploitation of these resources occurred. Fishermen harvested more than the allowed number of fishes leading to depletion of the fish population, disrupting the balance of the ecosystem. In this case, nobody thought about the stability of the fish population and everybody worked for their own benefit.

- Some fisheries also buy the rights for a particular fish found specifically in certain areas, causing over-exploitation of that fish species and reducing chances of other fisheries to capture that fish. This also leads to deterioriation of the ecosystem.

- Example for this is Cod fish found on the grand banks. The competition between fisheries lead to the depletion in the number of cod fish in these waters leading to an imbalance in the population.

Ans 1b) Marine habitats are the habitats that support Marine life. One of the marine habitats is- Coastal habitat.

Coastal Habitat

Coastal habitat involves the area where the land meets the sea. It is an ecosystem formed by mangroves, estuaries, coral reefs, beaches, rock pools, backwaters etc. Coastal habitats form an important part of the fisheries. They are ecologically and commercially important because they provide ground for spawning and nurturing of fish, shellfish and birds.

Biotic factors

1. Seagulls, crabs, pelicans are the invertebrates found in the coastal habitat.
2. Plants like mangroves are specially adapted to grow in the soil found in the coastal region.

Abiotic factors

1. Temperature- It plays a very important part in maintaining the marine ecosystem. Fishes are sensitive to temperature and need a certain degree of temperature for survival. Changes in temperature from the average value can lead to loss of nutrients and marine life in a marine ecosystem.
2. Sunlight- Another abiotic factor that maintains the aquatic life. Sunlight is needed by aquatic plants for photosynthesis which in turn provide nutrition to other organisms. Most of the aquatic life survives in sunlit areas under water.

Ecosystem

The coastal areas provide the following ecosystem:

• Mangrove ecosystem- This ecosystem provides home to the finfish and crustacean fishes. It also helps in nutrient filtration of the soil.
• Salt Marshes- These are found in estuaries and coastal areas. They are home to 75% of commercially viable fish.