By Scott Bisping and Andy Strickland
Golden shiners, Notemigonus crysoleucas, are one of the most popular, non-sportfish species in Florida and are greatly utilized among bass anglers throughout the state. Anglers trying to persuade the sometimes stubborn Florida bass to bite, often turn to golden shiners as the bait of choice. Of the 6,257 of submissions in the Florida TrophyCatch program (trophycatchflorida.com), 1,741 (28%) were caught on “natural bait” (primarily golden shiners). Golden shiners can be purchased at bait and tackle shops, where the price can range from $10-$26 per dozen depending on size and availability. Golden shiners at tackle shops are typically wild, and caught by commercial fisherman in public and private waters throughout the state. Harvest of wild shiners is largely unregulated, only requiring a commercial fishing license ($25) and a fish dealer’s license ($40) for commercial fisherman to harvest and sell golden shiners. There are no size or daily bag limits for commercial shiner fishermen, with no restriction on the size of cast net they can throw while fishing. In addition, recreational anglers who want to catch their own golden shiners to use as bait have no size or daily bag limit.
Such liberal regulation of a species with considerable economic value raised concerns with researchers. Research biologists had no data with regards to age and growth of the species. Thus, researchers designed a project to determine if golden shiners could be accurately aged using otoliths, and attempted to validate annulus formation. Lake Jackson (Leon County) was the study lake selected for this project. Golden shiners were collected by boat electrofishing using a SmithRoot model GPP 7.5 with direct pulsed current at 120 pulses per second, 1,000 volts (@ 6-8 amps). Golden shiners were collected monthly over a 12-month period. All fish were collected within 5 days of the middle of each calendar month. We determined an individual total length (mm) for each fish collected in addition to collecting the lapillar otoliths. The lapillar otoliths were removed from each individual by cutting through the ventral side of the cranial region. Once removed, the otoliths were cleaned, air dried, and stored in glass vials until they were processed. An attempt was made to collect 1-3 dozen golden shiners each month and follow a specific cohort over a 12-month period to ensure that annulus formation occurred only once per year.
More than 400 golden shiners were sacrificed for the project in 2015-2016. A total of 180 golden shiners that were sacrificed represented the 2013 year class. We performed a marginal increment analysis for the 2013 cohort by calculating an index of completion (C) for each otolith where (C = Wn/Wn – 1, where Wn is the width of the marginal increment on the distal edge of the otolith and Wn – 1 is the width of the most recent complete increment. Otolith measurements were taken with a microscope eyepiece on a direct horizontal plane. The marginal increment analysis validated that golden shiners form one annulus per year. The index value (C) was highest from January through March and lowest in May and June, indicating that annuli were deposited during April and May. We recommend the use of lapillar otoliths for aging golden shiners to determine population characteristics including annual mortality, growth, and recruitment. This information could be used to better understand golden shiner populations and potential impacts from an unregulated fishery.