How many dolphins are killed per tuna?

How Many Dolphins Are Killed Per Tuna?

The relationship between dolphins and tuna is a complex and contentious issue. Dolphins, as well as other marine animals, are often caught inadvertently in tuna fishing nets, resulting in significant bycatch and mortality. In this article, we will delve into the issue of how many dolphins are killed per tuna and explore the implications for marine conservation.

The Problem of Bycatch

Bycatch, which is the catching of non-target species in fishing gear, is a significant issue in the tuna industry. According to the Food and Agriculture Organization (FAO) of the United Nations, bycatch is a major threat to the survival of many marine species. Dolphins, in particular, are vulnerable to bycatch, as they are attracted to the schools of fish that tuna fishermen target.

The Impact of Bycatch on Dolphins

Estimated Annual Dolphin Mortality

• 80,000 dolphins: This is the estimated annual mortality of dolphins due to bycatch in tuna fishing nets (Source: Inter-American Tropical Tuna Commission)
• 4.1 million dolphins: This is the estimated total number of dolphins that have been killed in the Indian Ocean since the introduction of tuna fishing nets in the 1950s (Source: Mongabay)

Types of Tuna Fishing Gear Responsible for Bycatch

• Gillnets: These are the most common type of fishing gear used in tuna fishing, and they are responsible for a significant proportion of bycatch. Gillnets are large nets that are set at a depth of around 10-20 meters to catch tuna.
• Troll lines: Troll lines are used to catch tuna, but they also catch other marine animals, including dolphins.

Why Tuna Fishing Gear Is Ineffective

• Indiscriminate catching: Tuna fishing gear is not designed to target specific species, and as a result, many non-target species are caught, including dolphins.
• Lack of selectivity: Even if fishing gear is designed to target specific species, it is often not effective at excluding non-target species, leading to bycatch.

Efforts to Reduce Bycatch

• Improved fishing gear design: Researchers are working on designing fishing gear that is more selective and reduces bycatch.
• Changes to fishing practices: Changes to fishing practices, such as using different types of fishing gear or adjusting fishing times, can also reduce bycatch.
• Conservation efforts: Conservation efforts, such as protected areas and marine reserves, can also help reduce bycatch.

The Impact on Tuna Stocks

• Overfishing: Bycatch can lead to overfishing, as the number of fish caught in tuna fishing nets is higher than the number of fish that can be sustainably caught.
• Declining tuna stocks: As a result, tuna stocks are declining, which can have significant impacts on the environment and human communities that depend on tuna fishing.

Conclusion

Bycatch is a significant issue in the tuna industry, and it is having a devastating impact on dolphin populations. The estimated annual mortality of dolphins due to bycatch is staggering, and it is essential that we take action to reduce bycatch and protect dolphins. This can be achieved through improved fishing gear design, changes to fishing practices, and conservation efforts.