Cartabiano, E.C., D.R. Stewart, and J.M. Long. 2015. Effect of bait and gear type on turtle bycatch and Channel Catfish population parameter estimates in a reservoir. Journal of Freshwater Ecology 30:407-415. http://dx.doi.org/10.1080/02705060.2014.966165
Abstract
Hoop nets have become the preferred gear choice to sample channel catfish Ictalurus
punctatus but the degree of bycatch can be high, especially due to the incidental
capture of aquatic turtles. While exclusion and escapement devices have been
developed and evaluated, few have examined bait choice as a method to reduce turtle
bycatch. The use of ZoteTM soap has shown considerable promise to reduce bycatch of
aquatic turtles when used with trotlines but its effectiveness in hoop nets has not been
evaluated. We sought to determine the effectiveness of hoop nets baited with cheese
bait or ZoteTM soap and trotlines baited with shad or ZoteTM soap as a way to sample
channel catfish and prevent capture of aquatic turtles. We used a repeated-measures
experimental design and treatment combinations were randomly assigned using a
Latin-square arrangement. Eight sampling locations were systematically selected and
then sampled with either hoop nets or trotlines using ZoteTM soap (both gears), waste
cheese (hoop nets), or cut shad (trotlines). Catch rates did not statistically differ
among the gearbait-type combinations. Size bias was evident with trotlines
consistently capturing larger sized channel catfish compared to hoop nets. Results
from a Monte Carlo bootstrapping procedure estimated the number of samples needed
to reach predetermined levels of sampling precision to be lowest for trotlines baited
with soap. Moreover, trotlines baited with soap caught no aquatic turtles, while hoop
nets captured many turtles and had high mortality rates. We suggest that ZoteTM soap
used in combination with multiple hook sizes on trotlines may be a viable alternative
to sample channel catfish and reduce bycatch of aquatic turtles.