Trends in Hybridization Rates of Crappies (Pomoxis) in a Minnesota Lake Michael Lew 2005

Introduction There are two types of crappies: –Black: (Pomoxis nigromaculatus) –White: (Pomoxis annularis) Source: Source:

Introduction They sometimes cross-breed, forming a hybrid crappie –F1: A hybrid with one Black and one White parent –Fx: A hybrid with at least one hybrid parent

Introduction Travnichek et al. studied ten Alabama reservoirs from 1992 to 1995 –Found first-generation hybrid and advanced hybrid crappies –Proved hybrid crappies were fertile

Introduction Smith et al. studied Weiss Lake, Alabama from 1990 to 1991 –Found that first-generation hybrids grew faster in length to 254 mm than parent white or black crappies –Found that advanced hybrids grew slower in length to 254 mm than first-generation hybrids

Introduction Hooe and Buck et al. studied crappies in small aquaria from 1984 to 1989 –Found that first-generation hybrids outgrew parent white and black crappies over a period of three years –Found that advanced hybrids grew slower than first-generation hybrids over a period of three years

Introduction Crappies studied were from Fox Lake, Minnesota Years 1998, 1999, 2000, 2001, and 2002 were studied Part of a DNR goal to determine each lake’s “potential to produce large crappies”

Goals Determine trends in the rate of hybridization over five years Determine effects of hybridization on growth of the four categories (white, black, F1, and Fx) of crappies

Methods Preparation of Scale Samples 5% Chelex solution Incubated at 56°C overnight Polymerase Chain Reaction 10x Buffer 25 mM MgCl 2 10 mM dNTPs 100 mM Primer: LMA 104, LMA 117s, MS 13, LMA 21 Taq

Methods Gel Electrophoresis 10x TBE Acrylamide TEMED Ammonium Persulfate Gel Staining SYBR Gold Nucleic Acid Gel Stain ® UV Light Box

Results

Discussion Fx crappies grew similar in length to white crappies Age 0: p = Age 1: p = Age 2: p = Age 3: p = 0.331

Discussion Fx crappies grew similar in length to F1 crappies Age 1: p = Age 2: p = 0.668

Discussion Fx crappies grew larger in length than black crappies Age 0: p = Age 1: p = Age 2: p = Age 3: p = 0.224

Discussion F1 crappies grew larger in length than white crappies Age 1: p = Age 2: p =

Discussion F1 crappies grew larger in length than black crappies Age 1: p = Age 2: p =

Discussion Not enough data for F1 analysis for ages 0 and 3 Age 3 comparisons all had p-values higher than the significance value (p < 0.05)

Discussion Rate of hybridization was 10.5%, but not steady over the five years

Practical Analysis F1 hybrid crappies could be used for stocking lakes –Crappies are a popular sport fish and pan fish –Over fishing by the human population or a winter kill-off could present the need for stocking –F1 crappies grew significantly larger than parent white or black crappies –F1 crappies are fertile

Further Study Collect scale samples from every third, fourth, or fifth fish to ensure that data represents fish population more accurately Collect climate data at the lake to determine if there are effects of weather on hybridization

Acknowledgments Dr. Loren Miller Ms. Lois Fruen Team Research Mr. Brad Peterson Dave Carroffino Jason Roloff

Trends in Hybridization Rates of Crappies (Pomoxis) in a Minnesota Lake Michael Lew 2005 Source: Source: