Gastric mill age estimates for ringed crayfish Faxonius neglectus neglectus (Faxon) and the influence of temperature on band formation

Freshwater Crayfish
By: , and 

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Abstract

Counting bands via the gastric mill is a potential direct approach for ageing crayfish; however, the validity of ageing crustaceans using the gastric mill is unknown. Our study objectives were to 1) compare gastric mill age estimates to a traditional aging technique, 2) compare ageing precision among the ossicles, and 3) examine the effects of temperature on gastric mill band formation. From 2017–2018, we collected 681 ringed crayfish Faxonius neglectus neglectus (Faxon) from ten Ozark Highland streams. Our length-frequency analysis reflected seven age classes, whereas gastric mill age estimates indicated individuals were up to 10 yr of age. The length-frequency analysis age estimates showed good congruence (± 1 yr) with age estimates from the gastric mill 78% of the time. The coefficient of variation (CV) of age estimates from gastric mill bands between our readers was 29.7%. Ageing precision was highest when using the zygocardiac ossicles (CV = 12.4%). Gastric mill age estimates for known age-1 crayfish from a thermally stable laboratory were not significantly different from one, whereas age estimates from a thermally varying laboratory were greater than one. Our results indicate molting frequency does not control gastric mill band formation, and temperature plays a role in band formation.

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Publication type Article
Publication Subtype Journal Article
Title Gastric mill age estimates for ringed crayfish Faxonius neglectus neglectus (Faxon) and the influence of temperature on band formation
Series title Freshwater Crayfish
DOI 10.5869/fc.2020.v25-1.059
Volume 25
Issue 1
Year Published 2020
Language English
Publisher International Association of Astacology
Contributing office(s) Coop Res Unit Atlanta
Description 9 p.
First page 59
Last page 67
Country United States
State Arkansas, Missouri, Oklahoma
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