Capture Fisheries and Fishing Gear
What the exam tests
Capture fisheries questions test gear types, selectivity, fishing effort and management. You should distinguish active and passive gear, interpret catch per unit effort, and relate mesh size to sustainability in rivers and beels.
Core rules
- Active gear is moved to catch fish, such as cast nets, seines and trawls. Passive gear stays in place, such as gill nets, traps and hook and line.
- Gill nets entangle fish by the gills; mesh size determines the size range caught.
- Small mesh captures juveniles and can reduce future stocks; regulations set minimum mesh and closed seasons.
- Catch per unit effort (CPUE) = catch divided by effort, such as kg per boat-day. Falling CPUE can indicate overfishing.
- Bycatch is non-target catch; reduce it through selective gear and release practices.
- In Assam, beel and river fisheries need community rules, habitat protection and seasonal closures.
Worked example
Catch is 200 kg over 10 boat-days. CPUE = 200 / 10 = 20 kg per boat-day. If effort doubles to 20 boat-days and catch rises only to 300 kg, CPUE = 15. The lower CPUE suggests the stock is being fished harder and may be declining. Reasoning: compare catch with the effort needed to obtain it.
Traps
Do not call a gill net active gear. Do not judge gear only by catch; consider selectivity. Do not confuse CPUE with total catch. Do not ignore illegal mesh sizes.
Key facts
Cast nets are used in shallow water. Hooks and lines are selective. Traps are common in beels.