FISHING EFFORT & CPUE

Introduction Fisheries – integral part of most of the societies of the world It makes important contribution to economic and social health and well being in many countries World fish resources are suffering due to combined effort of heavy exploitation & environmental degradation

Introduction continued……. Increasing demand for fish and fishery products – world market – makes increase in fishing effort Modern navigational equipments Introduction of trawl nets Announcement of subsidies by governments 1960 & 1970 – World fish catch was in peak 1980s – stock depletion was seriously felt 1990s – Management of fisheries (FAO Code of Conduct for Responsible Fisheries

Acc. to FAO (2000) 47% of the 441 commercially important species are fully exploited 18% are over exploited 9 % depleted 1% recovering Living resources are limited but renewable Our aim is to get maximum yield for long time – sustainability Increasing effort – in developing countries – leads to sudden depletion of stocks

Fishing Effort Effort put by man for fishing. Total amount of fishing activity on fishing ground over a given period of time. The effort could be visualized in terms of - time devoted - implements used - technology adopted - money spent

Fishing Effort continued...... The amount of fishing gear of a specific type used on the fishing grounds over a given unit of time e.g. hours trawled per day, number of hooks set per day number of hauls of a beach seine per day

Eg. - No. of hauls / day - No. of hours / day - No. of hooks / day - No. of traps / day - Length of gill net / day - No. of dives / hour or day

When two or more kinds of gear are used, the respective efforts must be adjusted to some standard type before being added. The total fishing gear in use for a specified period of time. When two or more kinds of gear are used, they must be adjusted to some standard type.

Stock Assessment & Effort Advice on optimum exploitation Important basic requirement for stock assessment studies – Effort Fishing mortality is directly proportional to fishing effort Catch & Effort data is an input data in estimation of mortality parameters Fishing effort is useful measure to catch a given proportion of the fish stock/year.

Fishing effort measurement Three levels of precision of fishing effort are identified in reporting forms. Data should be provided for all three levels indicated as categories. Category A refers to a detailed unit of measure, e.g. hours fished or number of sets, etc. These units of measure will vary with the gear used.

Category B refers to "number of days fished", i. e Category B refers to "number of days fished", i.e., the number of days on which fishing took place. For those fisheries in which searching is a substantial part of the fishing operation, days in which searching but no fishing took place should be included in "days fished" data

The effort may be nominal, reflecting the simple total of effort units exerted on a stock in a given time period. It may also be standard or effective when corrected to take account of differences in fishing power and efficiency and ensure direct proportionality with fishing mortality. Relates usually to a specific fishery and gear

If more than one gear is considered, standardization in relation to one of them is necessary. For biologists, a good measure of fishing effort should be proportional to fishing mortality. For economists it should be proportional to the cost of fishing

Problems in Quantifying Effort Different sizes of gears Different technical specification Fisherman skills – not equal Developing countries - No log book - No proper record CPUE = Yield / effort

Fishing Effort in Fisheries Management Fishery resources are limited If the mortality due to fishing is not controlled – the fishery becomes economically non-viable & stocks collapse to extinction Two ways in the fisheries management i) Input Control (Effort Management) - Restrict the No. of fleets - Restrict the No. of gears - Size control of gears - Amount of fuel used

Controlling of Fishing Effort Both effort & catch management options should support biological economic ecological and social objectives

Biological – Target species – level of exploitation should ensure continued productivity. Economic – Maximize the income of fishermen. Ecological –Minimize the impacts of fishing on physical environment & on non target species Social – Maximize the employment opportunities

Methods of controlling effort Restriction on license Reduction of fleet capacity Restriction of fishing time Restriction on certain fishing gear

Conclusion Effort to be calculated with minimum error. Suitable sampling technique. Scientist and enforcing authority to jointly work.

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