Fishing Rod

Story Introduction

It is the seventh day after setting sail. Ian is navigating the Hope across the vast, calm ocean. He thinks today is the perfect day for a fishing break, but after searching everywhere on the boat, he can't find a fishing rod. So, Ian hopes that his friends can build a fishing rod with building blocks by themselves.

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Teaching Preparation

Name	Illustration
Nezha Pro Ocean Kit

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Teaching Objectives

1. Recognize the ratchet.
2. Understand the characteristics of the ratchet.
3. Understand the history and current situation of human marine fishing development.

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Learning and Exploration

By consulting relevant materials, explore the characteristics of the ratchet and understand its applications in daily life.

Construction Steps

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Case Demonstration

The reel seat of the fishing rod features a ratchet mechanism. When letting out the line, the ratchet is released; when reeling in the line, it makes a clicking sound.

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Extended Knowledge

Human Marine Fishing: From Historical Evolution to Global Practices of Sustainable Development

I. Historical Context and Development Stages of Marine Fishing

1. Ancient Times to the Middle Ages (Relying on Natural Fishing)

Evolution of tools: From primitive fishing nets and harpoons to wooden fishing boats. In China's Song Dynasty, "sea boats" were already used for fishing, and European Vikings used longships to catch cod.

Characteristics: Fishing range was limited to coastal waters, output was restricted by natural conditions, and it was mainly for subsistence (self-sufficiency).

2. Industrial Revolution to the 20th Century (Mechanization and Expansion Period)

Technological breakthroughs: Steam-powered fishing boats, refrigeration and preservation technology (19th century), sonar and radar (after World War II) promoted pelagic fishing. Japan and Norway became early pelagic fishing powers.

Impact: Global fishing output increased from 20 million tons to 80 million tons between 1950 and 1980, and the problem of overfishing began to emerge (such as the decline of cod resources in the North Sea).

3. 21st Century to Present (Crisis and Transformation Period)

Current situation: Global marine fishing output was about 85 million tons in 2020 (FAO data), but 34.2% of fish stocks are overfished. The international community is accelerating the promotion of sustainable fisheries management.

II. Main Methods and Technologies of Modern Marine Fishing

Fishing Method	Tools / Principles	Typical Applications	Ecological Impact
Trawl Fishing	Fishing boats drag net bags to filter water, divided into bottom trawling (close to the seabed) and midwater trawling	Cod, shrimp, demersal fish	Destroys seabed ecosystems, catches juvenile fish and non-target species as bycatch
Purse Seine Fishing	Surrounds fish schools with nets and then tightens them, often combined with fish finders for positioning	Tuna, herring and other schooling fish	May accidentally catch dolphins, sea turtles (e.g., tuna purse seines)
Longline Fishing	Main rope with thousands of hooks hanging to catch pelagic fish	Tuna, marlin, cod	Threatens seabirds (ingesting hooks by mistake)
Gillnet Fishing	Vertical nets where fish get stuck by their gill covers after touching the net	Sardines, mackerel	Difficult to distinguish species, high bycatch rate
Rake, Spear and Pot Fishing	Rakes scrape shellfish, pots trap crabs, lobsters	Scallops, king crabs	Destroys intertidal habitats, reduces benthic organisms

III. Key Data and Regional Characteristics of Global Marine Fishing

1. Production Distribution (2020 FAO data)

Top 5 countries: China (13.5 million tons), India (4.8 million tons), Indonesia (4.5 million tons), the United States (4.3 million tons), Vietnam (3.5 million tons).

Regional proportion: Asia accounts for 58% of global fishing output, the Atlantic Ocean and the Pacific Ocean contribute 32% and 28% respectively.

2. Current Status of Major Economic Fish Resources

Declining species: Atlantic bluefin tuna (commercial catches once dropped to 10% of historical levels), North Sea herring, Peruvian anchovy (fluctuating due to El Niño).

Cases of sustainable management: Alaskan pollock (resource recovery achieved through quota system, annual catch stable at 3 million tons).

IV. Ecological and Social Challenges of Marine Fishing

1. Environmental Crises

Overfishing: 34.2% of global fish stocks were overexploited in 2020, leading to food chain disruption (e.g., reduced sharks causing jellyfish blooms).

Bycatch issues: About 20 million tons of non-target organisms are accidentally caught each year (such as sea turtles, seabirds, dolphins), 30% of which are discarded.

Fishing gear pollution: About 640,000 tons of abandoned fishing nets ("ghost gear") are left in the ocean each year, entangling marine mammals and releasing microplastics.

2. Social and Economic Contradictions

Fishing-dependent communities: About 200 million people worldwide rely on marine fishing for a living. Coastal communities in developing countries are the most affected by resource decline (e.g., small-scale fishermen in West Africa losing their livelihoods due to the influx of EU fishing boats).

IUU fishing (Illegal, Unreported, Unregulated): Causes economic losses of 10-23 billion US dollars annually, disrupting international fisheries order (e.g., "pirate fishing" in Southeast Asian waters).

V. Global Practices and Solutions for Sustainable Fishing

1. Management Mechanisms

Quota system (TAC): The EU Common Fisheries Policy (CFP) sets fish catch quotas. In 2023, North Sea cod quotas increased by 40% compared to 2015.

Fishing moratoriums and no-take zones: China implements summer fishing moratoriums (May-September) in the Yellow Sea and Bohai Sea. In 2023, the East China Sea hairtail resources increased by 15% year-on-year; Pacific island countries established the Micronesian No-Take Zone (3 million square kilometers).

2. Certification and Standards

MSC (Marine Stewardship Council) certification: As of 2024, over 400 fisheries worldwide have passed MSC certification, covering 15% of output (e.g., Alaskan wild salmon, Norwegian cod).

ASC (Aquaculture Stewardship Council): Regulates the aquaculture sector but is mainly used to assess sustainability in marine fishing.

3. Technological Innovation

Selective fishing gear: Bottom trawls equipped with "Turtle Excluder Devices (TED)" reduce turtle bycatch by 90%; tuna longlines use bird deterrent devices (such as colored streamers) to reduce seabird mortality.

Digital monitoring: Satellite tracking of fishing vessels (e.g., Global Fishing Watch platform) for real-time monitoring of IUU fishing; AI identifies catch species to reduce bycatch.

VI. Future Trends: From "Extraction" to "Symbiosis"

1. Blue economy and ecological compensation: The EU launched "blue bonds" to fund sustainable fisheries projects; Indonesia piloted "payment for fisheries ecosystem services," where fishermen receive subsidies for protecting coral reefs.

2. Alternative proteins and aquaculture: Lab-grown fish meat (e.g., Singapore approved the first cell-cultured tuna in 2024), land-based recirculating aquaculture (reducing coastal pollution).

3. Deepened international cooperation: The 2023 UN High Seas Biodiversity Agreement came into effect, establishing the first global management framework for high seas fisheries, with plans to introduce a high seas fishing quota system by 2025.

Conclusion

Marine fishing is not only an important pillar of human civilization but also a key field testing the wisdom of sustainable development. From Viking longships to intelligent fishing vessels, the relationship between humans and the ocean is shifting from "conquest" to "co-governance" — only by taking scientific management as the anchor and technological innovation as the sail can the blue granary continue to nourish humanity.