Standard Sampling of Inland Fish: Benefits, Challenges, and a Call for Action

Abstract

There are many examples of how standardization of procedures in production and data collection have led to remarkable advances in industry and science, but standardization is lacking regarding protocols for sampling fish populations in inland, freshwater systems. Reasons given why biologists often resist standardized sampling protocols include perceptions that differences in regions invalidate standard techniques; use of standard sampling is costly and reduces innovation by regional biologists; the variation already present in nature masks any gains introduced by standardization; and historical trend data is lost. We examine these reasons and provide procedures that may serve as a template by describing how development and implementation of standardized sampling protocols were achieved by the Washington Department of Fish and Wildlife. These procedures included obtaining support from high‐level management within the agency and input from a wide variety of sources; emphasizing benefits to management biologists; designing procedures to be simple and cost‐effective; minimizing variation in catchability and maximizing catch; providing techniques for determining sample sizes; and field testing, reviewing methods, and training crews before implementation. Standardization can provide clear benefits and we discuss the option of developing nation‐wide or continent‐wide standards with leadership by the American Fisheries Society.

Spatial and seasonal patterns in freshwater ichthyofaunal communities of a tropical high island in Fiji

“…3), we observed high numbers of fish species that were only seen in one season. The reasons for the high degree of seasonal exclusivity are likely a combination of instantaneous variation in fish present during sampling (Bonar and Hubert 2002;McClanahan et al 2007) and species' preferences for particular seasonally available habitats and water characteristics. For example, many of those species only seen during the dry season spend significant portions of their adult lives in marine and estuarine environments and are potentially capitalizing on the longer upward penetration of saline water during this season for feeding, breeding or to escape predation (Rasalato et al 2010;McBride et al 2010).…”

A Preliminary Fishery Quality Index for Portuguese Streams

“…A different standard method and a probabilistic study design allowed a rigorous assessment of nearly all western U.S. streams and rivers (Whittier et al 2007;Pont et al 2009). Clearly, standard sampling methods are essential for spatially extensive assessments of fish populations and assemblages (Bonar and Hubert 2002;Hughes and Peck 2008;Bonar et al 2009). …”

Estimating abundance of endangered fish by eliminating bias from non-constant detectability

“…Many freshwater fish monitoring efforts rely on a fixed number of samples per year (Bonar & Hubert 2002). For example, the Río Yaqui fish monitoring program has relied on 8 to 30 samples pond −1 , where the number was fixed through time and dependent upon pond size.…”

“…For example, the use of information from historical surveys can be used to gauge the efficiency and shortcomings of the previous design, measure precision, and quantify the degree of inter-annual variability along with measurement issues related to variance components (Bonar & Hubert 2002). Aspects of the old versus a new sampling protocol should be evaluated using an experimental framework to determine the effects of measurement error on the utility of the index to generalize to the population's abundance (Kéry & Royle 2010).…”