Data collection systems should be designed to continuously improve the quality and quantity of data available for assessment and management, within the cost and capacity constraints of the fishery. It is important to carefully design data collection systems to match assessment methods and management needs. Many data collection systems have required much effort and cost but have not yet resulted in useful data. Using the baskets of fish approach to multispecies management (Step 5) may reduce data collection costs by reducing the number of management units in fisheries that harvest dozens of species for which it would be difficult to collect detailed data.
Well-designed collection programs should include data on the biological, social and economic aspects of the fishery. While biological data have long been considered necessary to determine the status of the fishery, social and economic data have not routinely been a part of data collection programs. Information such as market prices, fishing costs and revenues and employment characteristics can be highly informative and useful for determining the economic and social health of fishing communities. Poor economic health may be an indicator of declining fish populations. Information on fishing costs and revenue as functions of fishing effort is also necessary to estimate maximum economic yield.
Biological data should encompass both fishery dependent and independent data to fully assess the status of the fish stocks. Fishery dependent data on total catch (landings plus discards), landings and fishing effort can be gathered through the use of logbooks and representative dockside samples of length and weight. Unbiased scientific fishing surveys and underwater visual surveys of fish species, density and individual fish lengths, along with habitat types in both fished and unfished areas, also produce important fishery independent records. Additional biological data such as size at maturity and fecundity are also highly useful and can often be collected through relatively simple sampling programs.
In many locations, fishermen and local community members help design and carry out data collection and sampling programs. Incorporating the knowledge and manpower of local fishermen and their families can help reduce data collection costs, and the community-based approach may help increase the likelihood of successful management outcomes.