What are the forces that influence ocean currents? Describe their role in fishing industry of the world.
Approach · directive: “what / describe”
What it asks · Two parts: the forces that generate and modify ocean currents, and how currents shape the location and productivity of fisheries.
It asks 2 things — answer each
- What are the forces that influence ocean currents: primary (solar heating, wind, gravity, Coriolis) and secondary (density, coasts, seasonal winds)
- Describe the role of ocean currents in the fishing industry of the world: convergence, upwelling, migration, fish-finding and instability
Open with · Uneven solar heating, wind drag and Earth's rotation set ocean water moving; where currents mix or rise, they decide where fish gather.
Cover
- Primary forces: solar heating, planetary winds, gravity and the Coriolis force, which deflects flow right in the north and left in the south.
- Secondary forces: temperature, salinity and density differences; coastline and sea-floor shape; seasonal monsoon reversal in the north Indian Ocean.
- Convergence: Gulf Stream and Labrador at the Grand Banks, warm and cold waters off Japan, mix nutrients and support rich fisheries.
- Upwelling: Humboldt, Benguela, Canary and California currents raise nutrients that sustain anchovy and sardine fisheries.
- Fish-finding: INCOIS PFZ advisories use satellite sea-surface temperature and chlorophyll for India's coastal fishers.
- Instability: NOAA notes El Niño weakens upwelling and phytoplankton; warming shifts stocks; FAO SOFIA 2024 shows aquaculture overtaking capture.
Close with · With aquaculture now outstripping wild capture of aquatic animals (FAO, SOFIA 2024), the current-fed wild grounds must be managed as climate-sensitive commons that move as the oceans warm.
Add value (verified)
- NOAA: during El Niño, upwelling off the Pacific coast of South America weakens or stops, so phytoplankton and the fish that eat them decline.What are El Niño and La Niña? — NOAA National Ocean Service ↗“During El Niño, upwelling weakens or stops altogether. Without the nutrients from the deep, there are fewer phytoplankton off the coast”
- FAO SOFIA 2024: world fisheries and aquaculture output reached 223.2 million tonnes in 2022, and aquaculture of aquatic animals surpassed capture fisheries for the first time.FAO Report: Global fisheries and aquaculture production reaches a new record high — FAO Newsroom ↗“global fisheries and aquaculture production in 2022 surged to 223.2 million tonnes, a 4.4 percent increase from the year 2020”
- INCOIS Potential Fishing Zone advisories are meant for the fishing community: about 7 million people along India's 8,100-km coastline depend on fishing for their livelihood.Potential Fishing Zone (PFZ) Advisory — INCOIS ↗“About 7 million people living along the Indian coastline, spanning over 8100 km, are depending”
- PFZ advisories use satellite sea-surface temperature and chlorophyll, including Oceansat-II data.Potential Fishing Zone (PFZ) Advisory — INCOIS ↗“along with optical bands of Oceansat-II (India) and MODIS Aqua (USA) satellites are used for the identification of Potential Fishing Zones”
Question: UPSC's CS (Main) 2022, GS Paper I — paper ↗. Approach: Minimalist IAS, checked 16 Oct 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer· 334words · Minimalist IAS
The sun heats the oceans unevenly, winds drag their surface and Earth's rotation bends every moving mass. Together these set water flowing in currents, and where currents meet, rise or sink, they decide where fish gather.
Forces influencing ocean currents
- Solar heating: equatorial water expands and stands slightly higher, so it flows down the gentle slope towards the poles.
- Wind: planetary winds, the trades and westerlies, drag surface water into equatorial currents and drifts.
- Gravity: pulls water down pressure slopes and makes cold, dense water sink.
- Coriolis force: deflects moving water to the right in the northern hemisphere and left in the southern, closing the great gyres.
- Secondary forces: temperature, salinity and density differences drive slow thermohaline circulation; coasts and sea-floor relief deflect flow; the monsoon's seasonal reversal reverses currents in the northern Indian Ocean.
Role in the fishing industry of the world
- Meeting of warm and cold currents: the Gulf Stream meets the Labrador Current at the Grand Banks, and warm and cold streams meet off Japan; mixing feeds plankton and dense shoals.
- Upwelling coasts: cold currents on western margins, the Humboldt off Peru, Benguela off Namibia, Canary and California, lift nutrients that sustain anchovy and sardine fisheries.
- Cold current or upwelling
- nutrients reach the surface
- plankton bloom
- fish shoals
- rich fishing grounds
- Migration and seasons: currents carry eggs and larvae and guide migrating shoals, fixing when and where fleets work.
- Fish-finding: India's INCOIS issues Potential Fishing Zone advisories from satellite sea-surface temperature and chlorophyll, including Oceansat-II data, for the 7 million people along the coast who live by fishing.
- Instability: in an El Niño year, NOAA notes, upwelling weakens or stops and phytoplankton decline, hitting Peru's catch; warming is also shifting stocks.
Way forward
- Climate-ready management: quotas tied to current and temperature data, wider satellite advisories and protection of upwelling and spawning zones.
With aquaculture overtaking wild capture of aquatic animals in 2022 (FAO, SOFIA 2024), the current-fed wild grounds must be managed as climate-sensitive commons that move as the oceans warm.
Prepared by Minimalist IAS to the answer standard of Shivam Singh (mentor, 7 years) · facts checked against official sources (how we verify) · updated 16 Oct 2026. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.
