Sampling high biomass but rare benthic animals: Methods for surveying commercial clam stocks using a hydraulic dredge

Atlantic surfclams and ocean quahogs are large-bodied clams that inhabit the continental shelf of the Mid -Atlantic. Ecologically, they are the prevailing biomass on the shelf, yet in terms of numerical abundance they are not dominant in the benthic community and clams tend to be patchily distributed. The unusual characteristics of individual clams and their population distribution habits create difficult conditions for estimating overall abundance and biomass. Sampling and survey strategies need to be carefully tailored to these large-bodied, patchily distributed, infaunal animals to prevent undersampling or introduction of bias in surveys. Addition-ally, to compare data collected across multiple survey projects, consistent and comparable sample collection methods must be used. The ability to compare data across multiple surveys improves regional assessments of status and changes in populations. This paper provides recommendations, based on established best practices, for performing surveys of commercial clam stocks that should improve the quality of the data generated by those surveys and allow for data collected among various surveys and teams to be directly compared.

Automated summary

Atlantic surfclams and ocean quahogs are large-bodied clams that dominate the biomass on the Mid-Atlantic continental shelf. However, their numerical abundance is not dominant in the benthic community and they tend to be patchily distributed. Estimating overall abundance and biomass is challenging due to the unique characteristics of individual clams and their distribution habits. Proper sampling and survey strategies are crucial to prevent undersampling and bias. Moreover, consistent sample collection methods are essential to compare data across multiple surveys, improving regional assessments of population status and changes. This paper provides recommendations to enhance the quality of surveys and facilitate direct comparison of data among different surveys and teams.