The University of Southern Mississippi The Aquila Digital Community Master's Theses Spring 5-2018 Growth and Reproduction of Atlantic Chub Mackerel (Scomber colias) in the Northwest Atlantic Taylor T. Daley University of Southern Mississippi Follow this and additional works at: https://aquila.usm.edu/masters_theses Recommended Citation Daley, Taylor T., "Growth and Reproduction of Atlantic Chub Mackerel (Scomber colias) in the Northwest Atlantic" (2018). Master's Theses. 364. https://aquila.usm.edu/masters_theses/364 This Masters Thesis is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Master's Theses by an authorized administrator of The Aquila Digital Community. For more information, please contact [email protected]. GROWTH AND REPRODUCTION OF ATLANTIC CHUB MACKEREL (SCOMBER COLIAS) IN THE NORTHWEST ATLANTIC by Taylor T. Daley A Thesis Submitted to the Graduate School, the College of Science and Technology and the School of Ocean Science and Technology at The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Master of Science Approved by: Dr. Robert T. Leaf, Committee Chair Dr. Eric N. Powell Eric Robillard ____________________ ____________________ ____________________ Dr. Robert T. Leaf Dr. Robert J. Griffitt Dr. Karen S. Coats Committee Chair Department Chair Dean of the Graduate School May 2018 COPYRIGHT BY Taylor T. Daley 2018 Published by the Graduate School ABSTRACT Recent efforts to manage Atlantic Chub Mackerel (Scomber colias) in the northwest Atlantic have necessitated the description of the stocks life-history characteristics. The purpose of this study was to address the absence of regional information on growth and reproduction. Growth models were fit in a Bayesian framework. The length-at-age relationship was described using four non-linear candidate growth models, which were fit to total length (TL, cm) and age estimates (y). Age estimates were derived from whole otoliths for adults (n = 422) and ages of one month were assigned to larval fish (n = 60). The three-parameter VBGF was selected as the best -1 candidate model using Deviance Information Criterion (퐿∞ = 33.56 cm TL, k = 1.75 y , t0 = 0.07) to describe the weight-at-length relationship (a = 0.0258, b = 2.72). Sex and maturity were evaluated using histological techniques. A two-parameter logistic function was fit to length measurements (cm) and maturity estimates (n = 151) to describe length- -1 specific maturity for females (r = 0.38 cm , L50 = 27.39 cm TL). Age-at-50% maturity was estimated as 2.16 (y) by back calculation. Spawning season was estimated to occur during the months of January to April, using histological indicators and evidence of spawning from analysis of historical data on larval fish collections and commercial catch. These results can be used to inform the effective management of the Atlantic Chub Mackerel stock in the northwest Atlantic. ii ACKNOWLEDGMENTS The Science Center for Marine Fisheries provided funding for this project. Thank you to our industry liaison Jeff Kaelin from Lund’s Fisheries Inc., and Meghan Lapp from Seafreeze Limited whose companies provided us with fishery dependent samples. The insight they provided on the fishery and data for commercial landings was also extremely informative. Thank you to the Northeast Fisheries Science Center and its members who shared their expertise and hosted me, in addition to the fishery independent samples provided by the NOAA Groundfish survey. I would particularly like to thank Sandy Sutherland who was the second reader on all of the otoliths in this study. In addition, Eric Robillard provided valuable advice as a member on my thesis committee, allowed members of his lab to spend a great deal of time collaborating on this project, and worked with me to develop the methodology used for ageing otoliths in this research. Thank you to Dr. Eric Powell for serving on my committee. His attention to detail, vast knowledge of the literature, and valuable feedback greatly contributed to the projects quality. Nancy Brown-Peterson, a reproductive biology and histology expert provided essential training in histological techniques and was a second reader on all histology slides. Thank you to everyone who helped process fish especially Dr. Eleanor Bochenek, Kasea Price, and Dr. Ashely McDonald. I have learned so much from my labmates Meg Oshima, Corbin Bennetts, Nate Jermain, Grant Adams, and Morgan Corey and feel fortunate to be part such a supportive group of students in the Leaf Lab. A special thank you to my advisor Dr. Robert T. Leaf for providing me with the opportunity to work on this project. Your support and encouragement to learn new skills, collaborate, and attend meetings has been incredible. iii TABLE OF CONTENTS ABSTRACT ........................................................................................................................ ii ACKNOWLEDGMENTS ................................................................................................. iii LIST OF TABLES .............................................................................................................. v LIST OF ILLUSTRATIONS ............................................................................................. vi CHAPTER I – AGE AND GROWTH OF ATLANTIC CHUB MACKEREL IN THE NORTHWEST ATLANTIC ............................................................................................... 1 1.1 Introduction ............................................................................................................... 1 1.2 Methods..................................................................................................................... 4 1.3 Results ..................................................................................................................... 10 1.4 Discussion ............................................................................................................... 14 CHAPTER II – REPRODUCTIVE DYNAMICS OF ATLANTIC CHUB MACKEREL IN THE NORTHWEST ATLANTIC ............................................................................... 30 2.1 Introduction ............................................................................................................. 30 2.2 Methods................................................................................................................... 32 2.3 Results ..................................................................................................................... 36 2.4 Discussion ............................................................................................................... 39 REFERENCES ................................................................................................................. 63 iv LIST OF TABLES Table 1.1 Previous growth studies length-at-age parameter estimates ............................. 20 Table 1.2 Previous growth studies weight-at-length parameter estimates ........................ 22 Table 1.3 Length-at-age model parameter estimates ........................................................ 23 Table 1.4 Regional predicted length-at-age ...................................................................... 27 Table 2.1 Summary of reported length-at-maturity estimates .......................................... 46 Table 2.2 Summary of reported spawning season ............................................................ 47 Table 2.3 Histological processing sequence ..................................................................... 48 Table 2.4 Outline of tissue staining process ..................................................................... 49 Table 2.5 Indicators of maturity........................................................................................ 50 Table 2.6 Female reproductive phase terminology ........................................................... 51 v LIST OF ILLUSTRATIONS Figure 1.1 Bayesian structure of the three-parameter VBGF model ................................ 24 Figure 1.2 Bayesian structure of the power function used to describe weight-at-length .. 25 Figure 1.3 Length-at-age relationship ............................................................................... 26 Figure 1.4 Comparison of length-at-age relationship by region ....................................... 28 Figure 1.5 Weight-at-length relationship .......................................................................... 29 Figure 2.1 Historical commercial catch ............................................................................ 45 Figure 2.2 Mature female histology image ....................................................................... 52 Figure 2.3 Mature female histology image ....................................................................... 53 Figure 2.4 Immature female histology image ................................................................... 54 Figure 2.5 Male histology image ...................................................................................... 55 Figure 2.6 Non-gonadal tissue .......................................................................................... 56 Figure 2.7 Spawning capable male histology image ........................................................ 57 Figure 2.8 Comparison of fresh to frozen female gonad tissue ........................................ 58 Figure 2.9 Comparison of fresh to frozen male gonad tissue ........................................... 59