A Telephone-Diary-Mail Approach to Survey Recreational Fisheries on Large Geographic Scales, with a Note on Annual Landings Estimates by Anglers in Northern Germany
Malte Dorow and Robert Arlinghaus
Abstract.—Fisheries managers are looking for valid information on basic characteristics of recreational fisheries, such as landings data, to inform management decisions. We present a complementary survey approach designed to generate data on effort and harvest as well as various human dimensions of anglers using a telephonediary- mail survey design for a multispecies, multi-site fishery in a water-rich state in northern Germany (Mecklenburg-Vorpommern). First, a nationwide telephone screening was applied to estimate the total number of active resident and nonresident anglers in the study area. Afterwards, a 1-year diary study with randomly recruited resident and nonresident anglers was conducted. Routine check-up telephone calls were used to encourage the participants, generate detailed human dimensions data on the characteristics of anglers, and evaluate diary entries. After the end of the diary study, 648 anglers (58%) returned complete diaries. Responding diarists were significantly older, had a higher level of education, and encompassed more avid anglers than the nonresponding participants. Thus, diarists were weighted against external characteristics of a random sample of the resident angler population to reduce the risk of biased catch and harvest estimates. Indeed, estimates for harvest and effort based on weighted samples were significantly lower than unweighted mean estimates. Extrapolations of average annual harvest rates per angler to the population level revealed that for the most economically important fish species such as European eel Anguilla anguilla, Atlantic cod Gadus morhua, northern pike Esox lucius, common carp Cyprinus carpio, or Eurasian perch Perca fluviatilis, recreational fishing landings greatly exceeded commercial fisheries landings. Because diary estimates of annual angler landings were generally smaller relative to estimates of angler harvest stemming from 3-month recall periods using telephone surveys and on-site creel surveys, we concluded that the use of diary data likely resulted in conservative estimates of total landings. Our survey design may serve as a model for further studies because of its cost-effectiveness relative to standard creel surveys and because the panel structure of diary studies allows rich insights into individual angler behavior that is not possible to be accomplished by cross-sectional creel surveys.