Estimating Anadromous River Herring Natal Stream Homing Rates and Timing of
Juvenile Emigration Using Otolith Microchemistry
Benjamin Ian Gahagan
B.A., Kenyon College, 2002
A Thesis
Submitted in Partial Fulfillment of the
Requirements for the Degree of
Master of Science
At the
University of Connecticut
2010 APPROVAL PAGE
Master of Science Thesis
Estimating Anadromous River Herring Natal Stream Homing Rates and Timing of
Juvenile Emigration Using Otolith Microchemistry
Presented by
Benjamin Ian Gahagan, B.A.
Major Advisor______
Associate Advisor______
Associate Advisor______
Associate Advisor______
University of Connecticut
2010
ii ACKNOWLEDGEMENTS
The only place for me to begin these acknowledgements is with my parents. So many times through life I have been reminded how truly fortunate I am to have been born to two loving, courageous, intelligent people. Without your love, support and guidance, and that of my entire wonderful family: William, Gwyn, Marylou, and Anthony, none of this would have been possible. I am who and what I am because of you; there is no way to thank you enough for that.
I owe my advisor Dr. Jason Vokoun an immense debt of gratitude for making my time at the University of Connecticut productive on so many levels. Outside of the myriad ways in which he provided guidance and advice during this research he also helped me develop into a more thoughtful, caring, and introspective conservationist. It is with some trepidation that I graduate; I suspect I will never again have a supervisor so willing and enthusiastic to contemplate not only the ‘how’ but the ‘why’ of natural resource management. This has been a gift the past three years and one I will not forget.
Dr. Eric Schultz has fostered my scientific curiosity and development since I arrived at the University in 2005; I have benefited immensely from his experience, advice, and patience as I learned how to conduct scientific research. Without him I would not have been able to accomplish this. Dr. Peter Auster and Dr. Greg Whitledge both contributed significantly to my progress and this work, my expertise and this thesis are immeasurably better for it. If not for Dr. Auster I would be ignorant of the magnificence of dress sneakers and possess a poorer sense of what an aquatic scientist can and should accomplish. Dr. Jack Clausen, Deb Horton, and Beth Sheldon also deserve many thanks for all the bumps in the road they made smoother.
iii Many thanks are due to my fellow graduate students and the numerous friends and undergraduate students who helped me in some phase of this study: David Ellis,
Brian Hiller, Yoichiro Kanno, Bruce Gregoire, Mike Turner, Acima Cheriyan, Alicia
Landi, Katie Gerhard, George Maynard, Anson Smigel, Diane Alix, Mike Rege, Joe
Cassone, Kevin Job, Jon Velotta, Bill Embacher, Brian Embacher, Roger Fecteau, Mike
Davidson, Neal Hagstrom, and Linda Bireley.
A special thanks to the folks at Connecticut Department of Environmental
Protection Inland Fisheries’ Diadromous Project and Eastern Division. They volunteered their advice, time, fish, and equipment, often when I needed it the most. An additional thanks to Steve Gephard for recognizing some potential in me and being a mentor as I found my way; it was and is appreciated.
Willy, Dave, Roger, Justin…I can’t count the number of times you guys were there when I needed you. Whether it was fish talk (Willy, you even pretended to be interested!), a morning on the water, daybreak in a corn field or swamp, those precious moments in the cobalt blue waters of the canyons, or most importantly making me smile and laugh when I needed it the most…You guys were the best friends a man could ask for. Thank you.
Trish, you have made this last year, one which should have been among the hardest, the best. Your smile, your heart, your laugh gave me strength and happiness and always reminded me that I had the best times ahead.
iv ABSTRACT
Alewife (Alosa pseudoharengus Wilson) and blueback herring (Alosa aestivalis
Mitchill) are two closely related fishes in the family Clupeidae. Over the past two decades documented population declines have led four states, Connecticut,
Massachusetts, Rhode Island, and North Carolina, to close their river herring fisheries and the National Marine Fisheries Service to list river herring as Species of Concern under the Endangered Species Act. Information concerning the natal origins and individual movements of adult fish returning from the sea to spawn has been unattainable but is needed; philopatry and data on the movements and history of individual fish are important to understanding fish ecology and population dynamics. Otolith microchemistry combines the unique temporal properties of the otolith with the chemical history of the fish in the form of variation in minor and trace elements within the otolith.
These data were used to 1) investigate the natal fidelity of alewife and blueback herring,
2) retrospectively estimate the age at emigration of returning fish, and 3) correlate this early life history component with eventual growth and fitness for individual fish.
Ten sites were sampled across the state of Connecticut representing three separate habitat types: coastal headpond, cove, and riverine. Water samples were collected at all sites in early summer and in autumn in 2008 and 2009 to characterize water chemistry.
Returning adult alewife and blueback herring were collected from March through June during the spring season of 2008 and 2009. Five hundred forty-four alewife ranging from
218 to 312 mm and two hundred forty blueback herring were retained; total lengths
v ranged from 210 to 307 mm. Five age 0 fish per site were collected from 6 of the 10 sites in September - October of 2008 and 8 of the 10 sites in September – October 2009.
Water chemistry varied at sites for multiple minor and trace elements but only differences in Sr:Ca and Ba:Ca were consistently reflected in the otoliths of the age 0 fish. Water chemistry at the sites had minimal inter-annual variation. Reclassification of age-0 alewife to their site of origin was variable (50 – 100%) but demonstrated that age-0 fish could be accurately reclassified to their putative natal nursery at some sites.
Reclassification of age-0 blueback herring to their site of capture was less successful (20-
57%) due to minimal differences in water chemistry at the three sites with adequate sample sizes.
Reclassification rates to site of capture for adult alewife were highly variable (10
– 85%) and canonical plots revealed that several site signatures were overlapping and composed of relatively dispersed individuals in multivariate space. Sites with more distinct signatures and relatively less dispersed individuals returned higher reclassification rates (64 -85%). Adult blueback herring reclassification rates were almost exclusively low (15 – 83%) due to overlapping signatures for three of the four sites which were all tributaries of the Connecticut River. The fourth site had a distinct signature and a reclassification rate (83%) comparable to that of the highest alewife rate.
Reclassification of both age 0 and adult fish was complicated by variable early life histories which suggested a higher degree of movement as young of the year than has been previously documented and made characterization of natal signatures and collection of known-location fish problematic.
vi Age at emigration (days) was retrospectively estimated for 38 fish, 26 alewife and
12 blueback herring, and its influence on length at age 1 (millimeters), length at maturity
(millimeters), and age at maturity (years) was assessed using the Pearson Correlation coefficient. Length at maturity and age at maturity were combined into principal components. Age at emigration was variable in both species; fish emigrated after as few as 30 days and as many as 139. Length at age 1 was negatively correlated to age at emigration; fish that emigrated at younger ages were longer at age 1. Relationships between age at emigration and length and age at emigration were weak but age at emigration was positively correlated to the second principal component. Age at maturity had a positive loading on the second component while length at maturity had a negative loading, meaning that fish that emigrated younger returned at an earlier age and larger size than fish that emigrated at a greater age.
vii TABLE OF CONTENTS Page Acknowledgements……………………………………………………………………... iii Abstract…………………………………………………………………………………... v List of Tables…………………………………………………………………………..... ix List of Figures………………………………………………………………………….… x Chapter 1. River Herring Biology, Life History, and Status……………………………. 1 Setting…………………………………………………………………………... 11 Chapter 2. Estimating Anadromous River Herring Natal Stream Homing Rates Using Otolith Microchemistry…………………………………………………………………. 16 Methods…………………………………………………………………………. 21 Results…………………………………………………………………………... 27 Discussion………………………………………………………………………. 35 Chapter 3. Retrospective Determination of River Herring Daily Age at Emigration and Relationship to Subsequent Life History……………………………………………….. 55 Methods………………………………………………………………………… 58 Results…………………………………………………………………………... 64 Discussion………………………………………………………………………. 68 Literature Cited…………………………………………………………………………. 81 Appendix A…………………………………………………………………………….. 92 Appendix B……………………………………………………………………………. 109 Appendix C……………………………………………………………………………. 111 Appendix D……………………………………………………………………………. 115 Appendix E……………………………………………………………………………. 119
viii LIST OF TABLES Page
2.1. Results of quadratic discriminant function analysis with jackknife procedure for age 0 alewife. The number of fish analyzed per site is the total for each row. Classification accuracy back to site of collection was based upon otolith Sr:Ca and Ba:Ca………………………… 45
2.2. Results of quadratic discriminant function analysis with jackknife procedure for adult alewife. The number of fish analyzed per site is the total for each row. Classification accuracy back to site of collection was based upon otolith Sr:Ca and Ba:Ca (Site codes: BB = Bride Brook; EM = Eightmile River; HR = Housatonic River; MR = Mianus River; PB = Poquetanuck Brook; PR = Pequonnock River; QR = Quinnipiac River; SH = Shetucket River)……………………………………….………..……………… 46
2.3. Results of quadratic discriminant function analysis with jackknife procedure for adult blueback herring. The number of fish analyzed per site is the total for each row. Classification accuracy back to site of collection was based upon otolith Sr:Ca and Ba:Ca…………………………………………………………………………… 47
3.1. Summary table of species, sex, and age in years for alewife and blueback herring used in the study.…………………………………………….. 74
3.2. Mean lengths at age for alewife and blueback herring based upon recorded lengths at capture and back calculations. Back calculated lengths were generated using the proportional Dahl-Lea method on measurements from scales……………………………….. 75
ix LIST OF FIGURES Page
1.1. Map of the north shore of Long Island Sound with study sites. Sites are color coded by habitat type: black circles are headpond sites, dark gray circles are coves, and light gray circles are riverine sites. Red dots represent dams. Locations are accompanied by their respective two letter codes. From west to east the sites are Mianus River, Pequonnock River, Housatonic River, Quinnipiac River, Farmington River, Wethersfield Cove, Eight Mile River, Bride Brook, Shetucket River, and Poquetanuck Brook.………………………. 15
2.1. a Mean water Sr:Ca (SE) and b mean water Ba:Ca (SE) for the 10 collection sites. In each panel means that are marked with the same letter are not significantly different (ANOVA with Tukey’s HSD test on log transformed values, P < 0.05).………….…………… 48
2.2. a Linear regression of individual age 0 alewife otolith Sr:Ca on mean water Sr:Ca and b Linear regression of individual age 0 alewife otolith Ba:Ca on mean water Ba:Ca. All data are log- transformed...…………………………………………………………………… 49
2.3. a Linear regression of individual age 0 blueback herring otolith Sr:Ca on mean water Sr:Ca and b Linear regression of individual age 0 alewife otolith Ba:Ca on mean water Ba:Ca. All data are log- transformed...…………………………………………………………………… 50
2.4. Plot of Canonical Variates 1 and 2 created through quadratic discriminant function analysis including age 0 alewife Sr:Ca and Ba:Ca....……………………………………………………………… 51
2.5. Plot of Canonical Variates 1 and 2 created through quadratic discriminant function analysis including adult alewife otolith Sr:Ca and Ba:Ca. Points represent individuals collected from the indicated sites and ovals are 95% confidence ellipses around group centroids generated from the samples…………………………………… 52
2.6. Plot of Canonical Variates 1 and 2 created through quadratic Discriminant function analysis including adult blueback herring otolith Sr:Ca and Ba:Ca. Points represent individuals collected from the indicated sites and ovals are 95% confidence ellipses around group centroids generated from the samples…………………………………… 53
2.7. Representative Sr:Ca and Ba:Ca transects of adult direct migrations (a and b), age 0 indirect migrations (c and d) and adult indirect migrations(e and f). All transects proceed from the core of the
x otolith towards the edge. X-axes are unequal and represent the distance from the otolith core in microns; age 0 transects are complete but adult transect are abbreviated at the point of migration to saltwater. The left y-axes are unequal and denote otolith Sr:Ca concentration (umol/mol). The right y-axes are unequal and denote otolith Ba:Ca concentration (umol/mol)………………...… 54
3.1. Demonstration of the techniques used to combine otolith microchemistry data and the ability to count daily growth increments to estimate the age at emigration for juvenile river herring (PR913). The red circles mark daily growth increments (n = 58), the straight red line marks the path of laser ablation to the point the fish emigrated. On the graph the solid red line is otolith Sr:Ca (µmol/mol) and the dashed blue line is Ba:Ca (µmol/mol)…………………………………………………... 76
3.2. Scale from an alewife with, freshwater zone (FWZ), annuli, and spawning check marked. Spawning checks result when a fish enters freshwater to spawn and scale erosion occurs. Spawning checks are counted as an annulus.....……………...... 77
3.3. Bar graphs depicting the frequency distributions for age at emigration, total length (mm) at maturity, and age at maturity for alewife (Figs. a - c) and blueback herring (Figs. d - f). The bars are stacked by sex with males depicted in light blue and females in dark blue. The Y-axes represent the number of individuals observed and are unequal. The X-axes represent age at emigration (Figs. a and d), total length (mm) at maturity (Figs. b and e), and age at maturity (Figs. c and f)…………………… 78
3.4. Scatterplots of length at age 1 (mm) against age at emigration (days) and length at maturity (mm) against age at maturity (years) for alewife (Figs. a and b) and blueback herring (Figs. c and d). Females are represented by open circles and males by closed triangles…………………………………………………………….… 79
3.5. Scatterplots of Principal Component 2 (increased age at maturity – decreased size at maturity) against age at emigration (days) for alewife (a) and blueback herring (b). Females are represented by open circles and males by closed triangles…………………………………………………….… 80
3.6. Scatterplots of Principal Component 2 (increased age at maturity – decreased size at maturity) against length at age 1 (mm) for alewife (a) and blueback herring (b). Females are represented by open circles and males by
xi closed triangles…………………………………………………………………. 81
xii CHAPTER ONE
River Herring Biology, Life History, and Status
Introduction
Alewife (Alosa pseudoharengus Wilson) and blueback herring (Alosa aestivalis
Mitchill) are two closely related fishes in the family Clupeidae. The two species are so similar in appearance and aspects of their biology that they are often managed jointly as
‘river herring.’ Over the past two decades documented population declines have led four states, Connecticut, Massachusetts, Rhode Island, and North Carolina, to close their river herring fisheries. Early in 2007 the National Marine Fisheries Service (NMFS) listed river herring as Species of Concern under the Endangered Species Act (NMFS 2007).
Ecological information about the two species is lacking in several areas, including knowledge of the juvenile life stage, movements in the marine environment, and accurate natal homing rates (Greene et al. 2009). This study seeks to complement what is currently known about these fish by using otolith microchemistry to collect individual level data from adult fish that had returned to freshwater for their spawning run.
Alewife and blueback herring are anadromous, spending the majority of their life in marine habitats but returning to breed in freshwater. The ranges of the two species overlap, alewife being found between Labrador, Canada south to Georgia, USA and blueback herring ranging from New Brunswick south to the St. John’s River in Florida
(Loesch 1987). The two species are similar in size; alewife are somewhat deeper bodied and can reach 36 cm while blueback herring grow to 34 cm (Collette and Klein-MacPhee
2002). The species can be distinguished externally by differences in eye diameter, and internally by the color of the peritoneal lining, which is considered to be a more reliable
1 difference (Messieh 1977). Scale (MacLellan et al. 1981) and otolith morphology (Price
1978) have also been suggested as reliable methods to differentiate the two species.
Alewife and blueback herring typically return to freshwater to spawn for the first time at age 3 or 4 (Havey 1961; Marcy 1969). While a number of adult fish may die during or after the spawning migration, both species are considered iteroparous throughout most of their range (Loesch 1987). As with the closely related American shad
(Alosa sapidissima), there appears to be a cline where blueback herring reproductive strategy shifts towards semelparity south of Cape Fear, North Carolina (S. Winslow,
North Carolina DMF, pers. comm.). Both river herring species are able to reach at least 8 years of age, meaning a single fish could possibly return to freshwater to spawn for 4 to 5 consecutive years (Havey 1961; Marcy 1969).
The two species differ in spawning migration timing, although the runs often overlap. Alewives enter rivers to spawn in the early to mid-spring when water temperatures reach between 16° C and 19° C (Ellis and Vokoun 2009; Loesch 1987).
Blueback herring migrate when freshwaters reach 21° C, usually about a month to a month and a half after alewife spawning has commenced (Loesch 1987). Early observations and research suggest a moderate degree of natal homing (Carscadden and
Leggett 1975; Jessop 1994; Messieh 1977; Thunberg 1971) but less than that of salmon or American shad (Messieh 1977). A tagging study of spawning adults demonstrated that mature alewife and blueback herring are capable of homing to natal rivers and even to specific areas within a river system in subsequent spawning seasons (Jessop 1994).
Recent genetic research has been conflicting, indicating degrees of reproductive isolation among spawning stream populations in Maine (Bentzen and Paterson 2005) but also
2 finding that there is little genetic differentiation over spatial scales as large as 80km
(Palkovacs et al. 2008) further confirming that natal homing influences river herring population dynamics.
The two species select different spawning habitat. Alewife spawn almost exclusively in lentic habitats while blueback herring utilize lotic waters in the sympatric range of the two fish (Collette and Klein-MacPhee 2002; Loesch 1987). However, blueback herring have been shown to utilize a wider array of spawning habitats, especially in the absence of alewife (Loesch 1987; Walsh et al. 2005). Both species are group broadcast spawners and have variable fecundity (Loesch 1987). A single female is capable of producing nearly half a million eggs in a single spawning season (Jessop
1993).
After hatching, larval river herring develop for a period of 3 to 7 months in freshwater nursery grounds (Kosa and Mather 2001; Richkus 1975; Yako et al. 2002) but may leave in as few as 30 days depending upon developmental rate and environmental cues such as rain events (Gahagan et al. 2010a). Fish size can range between 28 mm to over 100 mm at time of emigration (Gahagan et al. 2010a; Kosa and Mather 2001; Yako et al. 2002). As juveniles, anadromous alewives feed on zooplankton and are capable of reshaping the plankton community in their natal ponds (Post et al. 2008). Larval and juvenile river herring suffer very high levels of mortality in nursery areas (Havey 1973;
Kissil 1974) partly because they are prey for other fish as well as terrestrial and avian predators (Loesch 1987; Yako et al. 2000).
Little is known about the movements and habitat use of juvenile and sub-adults after leaving nursery areas as juvenile river herring are fragile and typically unable to
3 cope with prolonged handling stress, making tagging difficult. It is presumed that juvenile fish migrate to saltwater in a direct fashion but alternative patterns of migration
(e.g. overwintering in freshwater or estuaries) have been observed in river herring from the Hudson River (Limburg 1998a). Juvenile fish production has been positively correlated to year class strength of returning adults (Jessop 1990).
River herring are integral components of aquatic ecosystems because they are consumed by a wide range of predators, thereby linking planktonic productivity to higher trophic levels. Aquatic, avian, and terrestrial predators all rely on river herring to form part of their seasonal diet (Durbin et al. 1979; MacAvoy et al. 2000; Uphoff 2003; Walter et al. 2003; Yako et al. 2000). Like Pacific salmon they also serve as vectors transporting marine derived nutrients to inland ecosystems (Browder and Garman 1994; Durbin et al.
1979; Garman 1992; Walters et al. 2009). River herring have socio-economic importance as commercial fisheries for river herring historically had been extensive and they are caught recreationally for consumption or use as bait in many states. Currently, U.S. landings amount to roughly 1,000 metric tons a year, down from an annual average of
25,000 mt between 1950 and 1969 (Schmidt et al. 2003). Over the last 40 years Virginia and North Carolina have reported over 70% of the total landings of river herring
(Schmidt et al. 2003).
Alewife and blueback herring have decreased in abundance across much of their range in the last 15 years. Multiple runs have decreased to the point that returning adult abundance is less than 1% of historical numbers (Haas-Castro 2006). Currently, the
Atlantic States Marine Fisheries Commission (ASMFC) manages the population through the Interstate Fishery Management Plan for Shad and River Herring and has initiated a
4 priority stock status review for the two species. There has not been a full stock assessment since 1990 (Crecco and Gibson 1990). However a recent assessment based on data from large rivers across the species’ range found that both species of fish showed significant signs of overexploitation in all rivers examined (Schmidt et al. 2003). The blueback herring run in the Connecticut River, as measured by returns to the Holyoke
Dam, has dropped from over 600,000 fish in the mid 1980’s to 39 fish in 2009 (Gephard et al. 2009).
There have also been documented changes in population demography. Studies comparing runs from the past 10 years to runs in the 1960’s and 1970’s have shown that many spawning cohorts are now composed of herring that are significantly smaller in body size, younger in average age, younger at sexual maturation, and dominated by virgin fish. This phenomenon has been recorded across the species’ range in both large river systems (Jessop 2003; Schmidt et al. 2003) and a small coastal stream (Davis and
Schultz 2009). The types of changes seen in alewife and blueback herring demography have frequently been associated with increased fisheries or natural mortality on the adult life stages (Beard and Essington 2000; de Roos et al. 2006; Jessop 2003; Law 2000;
Olsen et al. 2004). River herring have been reported as bycatch in both the Atlantic herring and mackerel fisheries (Harrington 2005; McAllister 2007).
The scientific information currently available for river herring has been derived from decades of studies using various fisheries techniques. These methods have allowed researchers to learn about river herring populations and the biology of the two species but have not enabled much information to be gathered about natal origins or individual movements of returning adults. Philopatry and individual-level histories are important to
5 understanding growth and movement patterns as well as population dynamics. Modern approaches to quantify the variation in otolith microchemistry now facilitate research into both of these subjects.
Otoliths
Otoliths (ear stones) are found in the inner ears of fish. They lie upon sensory cilia within the maculae and are of a higher density than the surrounding fluid. Otoliths stimulate the cilia transmitting nerve impulses that allow fish to sense motion, gravity, and near-field sound (Hawkins 1981; Lowenstein 1971; Popper et al. 2005). By weight they are approximately 96% calcium carbonate (CaCO3), 3% organic matrix, and less than 1% trace elements or metals (Campana et al. 1997; Proctor et al. 1995; Sie and
Thresher 1992). Otoliths are formed in the membranous labyrinth of the inner ear through biomineralization, primarily of calcium and carbonate, from the endolymph
(Campana and Thorrold 2001; Wheeler and Sikes 1984). Fish have three types of otoliths: the asteriscus (within the lagena), lapillus (utriculus), and sagitta (sacculus). The sagitta are typically the largest and the asteriscus the smallest.
In scientific studies the sagittal otolith is used almost exclusively over the asteriscus or lapilla, because its larger size makes it easier to locate, remove, and manipulate (Campana and Neilson 1985). Of the three possible crystalline forms of calcium carbonate, sagittae are nearly always composed of aragonite, although they are occasionally found in an alternate vaterite state (see Campana 1999 for review).
Otoliths have been studied by fisheries biologists for over a century (Reibisch
1899). The formation of annual bands (annuli) allows for the estimation of age for many species of fish. In their first months of life, fish accrete new materials onto the otolith at
6 a variable diel rate that creates daily growth increments (Pannella 1971). Otoliths make excellent recorders of age in fish because, unlike other hard parts such as bones or scales, they are metabolically inert. As a result, even in times of physiological stress they are neither resorbed nor reconstituted and form a continual, permanent record of a fish’s growth (Campana and Neilson 1985). Otoliths also record environmental information in the form of trace elements (primarily metals) that vary across environments in which a fish occurs and are deposited in the crystalline structure along with or in the place of calcium carbonate. These elements are locked in place and through otolith microchemistry techniques can be paired with the daily or annual bands on the otolith to create a microchemical timeline (Campana et al. 2000).
Otolith Microchemistry
More than 30 elements have been identified within the otoliths of fish (Campana
1999). The inclusion of minor and trace elements in the otolith is most often the result of ion substitution for Ca2+ or from the co-precipitation of an alternative form of carbonate
(Campana 1999). These alternative otolith constituents are largely derived from the aqueous environment surrounding the fish rather than food or metabolic processes
(Dorval et al. 2007; Fowler et al. 1995; Gallahar and Kingsford 1996; Walther and
Thorrold 2006b). While the concentration of elements in the water and in the otolith can be correlated, some elements are less suitable for use in microchemical studies than others. Physiological processes (Kalish 1989), environmental conditions (Bath et al.
2000; Bath Martin et al. 2004; Elsdon and Gillanders 2002; Gallahar and Kingsford 1996;
Thorrold et al. 1997), and elemental association with the organic matrix rather than the
7 crystalline structure of the otolith (Campana et al. 2000; Proctor and Thresher 1998) can all decouple the water:otolith relationship.
The use of otolith microchemistry has taken time to mature but is now an accepted fisheries science tool. Initially some researchers possessed doubts as to the accuracy, reproducibility, and overall utility of otolith microchemistry studies (Campana et al. 1997; Milton and Chenery 1998; Proctor and Thresher 1998; Thresher 1999).
Advancements in technology and refinements in methodology have resulted in reproducible results in marine, estuarine, and freshwater habitats and proven that otoliths can be accurate sources of an individual’s environmental history (Bickford and Hannigan
2005; Brazner et al. 2004a; Brazner et al. 2004b; Feyrer et al. 2007; Kellison and Taylor
2007; Tomas et al. 2005a; Veinott and Porter 2005; Whitledge et al. 2007). To date studies have shown that Sr, Ba, Na, Mg, K, Li, U, Mn, Fe, Ni, Cu, and Zn can act as discriminatory factors when researchers are attempting to develop ‘elemental fingerprints’ for specific habitats (Campana et al. 2000).
There are various techniques that can be used to analyze the microchemistry of fish otoliths. When resolving specific portions of a fish’s life history, the otolith, or a section thereof, can be dissolved in a solution of known composition and analyzed after drying. When seeking finer resolution in temporal or spatial information a whole otolith can be prepared and then analyzed using a precise probe. Probe microchemistry has two important advantages. First, it is non-destructive, allowing for repeated microchemical analysis or later non-chemical analyses. Second, it allows for patterns to be linked to growth increments, adding a temporal scale to the analysis. The most commonly used probe technique is laser ablation inductively coupled plasma mass spectrometry (LA-
8 ICP-MS) as it provides consistent, controllable, high resolution analyses of otolith microchemistry (Campana et al. 1997; Ludsin et al. 2006; Thorrold and Shuttleworth
2000; Whitledge et al. 2007).
Previous otolith microchemistry studies have focused on topics ranging from the detection of migration patterns such as diadromy (Kennedy 2002; Limburg 1998b; Secor
1992), to stock delineation (Bickford and Hannigan 2005; Feyrer et al. 2007; Miller et al.
2005; Patterson et al. 2004; Proctor et al. 1995; Thresher 1999), natal origins (Brazner et al. 2004b; Hobbs et al. 2005; Thorrold et al. 1998a; Thorrold et al. 2001; Tomas et al.
2005a; Veinott and Porter 2005; Whitledge et al. 2007) and examination of an individual’s environmental life history (Bath Martin et al. 2004; Brazner et al. 2004a;
Elsdon and Gillanders 2002; Fowler et al. 1995; Kennedy 2002). Studies that have focused on diadromy and the identification of natal areas are most relevant to the objectives of this project.
Researchers noted the ability to detect diadromy early in the development of otolith microchemistry (Kalish 1990; Limburg 1998b; Secor 1992; Secor et al. 1995;
Volk et al. 2000; Zimmerman and Reeves 2002). As fish pass across gradients from low to high salinity there is a marked increase in Sr:Ca and corresponding decrease in Ba:Ca within the otolith, presumably as a reflection of environmental availability (Bath Martin et al. 2004; Elsdon and Gillanders 2005; Secor et al. 1995; Zimmerman 2005). The ability to detect important events in early life history such as emigration to saltwater allows for retrospective analysis of migration timing and its effects on the development of that fish to maturity.
9 The ability to isolate the portion of an adult anadromous fish’s otolith that corresponds to the time it spent in its natal nursery can be combined with statistical techniques to identify unique elemental signatures for different areas (Campana et al.
2000). Given proper coverage of natal areas, these signatures act as a chemical mark that allow for the retrospective assignment of individuals to natal areas (Brazner et al. 2004a;
Gillanders 2005; Thorrold et al. 2001; Veinott and Porter 2005; Whitledge et al. 2007).
For this method to be successful several conditions must be met. For variations in otolith chemistry among sites to exist there must be adequate variation in the availability of elements at the sites themselves (Campana 1999). Water chemistry at sites is influenced primarily by the underlying geology but can be mediated by other processes such as atmospheric deposition and organic inputs (Hem 1970). Spatial variation can easily be confounded by temporal variation; accurate natal site classification therefore requires that temporal variation within sites be low or that differences persist across time, which is not always the case. Temporal variation in site specific signatures often requires the creation of a library or ‘atlas’ that catalogs temporal variation at sites (Gillanders 2002; White and
Ruttenberg 2007). Finally, the period of juvenile residency in a specific area must be of sufficient duration for the otolith to record the signature of that environment.
As concern about these two species of anadromous fish grows it is important to realize that information about these fish is largely restricted to juvenile emigration patterns and the numerical abundance and physical characteristics of returning adults.
Insights into individual movements, sub-adult development, and the importance of emigration patterns observed in early life history have been scarce due the low economic value of these fish and the limitations of traditional tracking methods with fragile
10 juveniles. The objectives of this study were to provide information about natal fidelity and the effects of age-at-emigration for future river herring conservation and research.
To achieve the first objective, I assessed the ability of otolith microchemistry to provide estimates of natal fidelity at a fine spatial scale by isolating site specific natal otolith signatures and using them to classify adults on the spawning run to their site of origin.
Natal fidelity rates can be informative; homing may sharply influence population dynamics and connectivity and can influence extinction risk (Hastings and Harrison
1994; Schindler et al. 2010; Secor et al. 2009). From a management perspective it is useful to know the amount of mixing between runs and potential source and sink populations. The second objective was to retrospectively determine age at emigration of adult fish and determine what, if any, effects emigration timing had on subsequent life history. Early life history can have tremendous influence on the eventual fitness of an individual (Callihan et al. 2008; Conover et al. 2003; Schultz 1993) and can also provide insight into population level dynamics (Doak et al. 1998; Secor 2007; Secor et al. 2009;
Tilman et al. 1998).
Setting
This study took place within the state of Connecticut, USA, along the north shore of Long Island Sound (LIS). The north shore of LIS has a large number of rivers that support alewife and blueback herring runs and was an ideal area to examine natal homing over variable spatial resolutions. LIS is a 110 mile long tidal estuary bounded by
Connecticut and mainland New York to the north and west, and Long Island on the south.
The eastern end is open to Block Island Sound and the Atlantic Ocean with the exception of a chain of small islands extending from the north fork of Long Island. All the rivers in
11 this study are connected to Long Island Sound directly or through rivers they serve as tributaries to.
Fish were collected from 10 sites in 7 watersheds (Figure 1.1). The sites varied in size and distance from Long Island Sound. The 10 sites represent three different habitat types: riverine, coves of larger rivers, and headponds (natural and manmade) connected to LIS by a short stream segment.
Sites
Sites will be described in geographic order, starting from the western end of the state and moving to the east.
Mianus River: The Mianus River is a headpond site. The impoundment, Mianus Pond, is less than one km inland in the town of Greenwich, CT. A small river (mean width ≈50 m) exits the impoundment and flows into Long Island Sound. River herring enter Mianus
Pond by ascending a fish ladder. Both species of river herring use the site.
Pequonnock River: The Pequonnock River is a headpond site. An impoundment,
Bunnell’s Pond, is 3.4 rkm from Long Island Sound. Below the impoundment the
Pequonnock River is small (mean width ≈ 12 m and highly altered (channelized, rerouted under city infrastructure). The river empties into Long Island Sound in Bridgeport, CT.
Only alewife utilize the Pequonnock River, entering Bunnel’s Pond via a fish ladder at the dam.
Housatonic River: The Housatonic River is a riverine site. The Housatonic empties into Long Island Sound between Fairfield and Milford, CT. The Derby Dam, the first dam on the Housatonic, is 20.6 rkm upstream in the town of Derby. There is no fish
12 passage at the Derby Dam and it represents the upstream limit of river herring migration in the river. Both species of fish use the Housatonic River as spawning habitat.
Quinnipiac River: The Quinnipiac is a riverine site. It flows into Long Island Sound in
New Haven, CT. The first impediment to migration is the Wallace Dam, 23.3 rkm upstream in Wallingford. The river is used by both species of river herring.
CONNECTICUT RIVER: Measuring 655 km, the Connecticut is the largest river in southern New England and its watershed includes parts of Connecticut, Massachusetts,
Vermont, New Hampshire, and Quebec. The head of tide is in Windsor Locks, 97 rkm upriver from the mouth. There are three study sites located on the Connecticut River.
The sites will be addressed moving from the mouth of the river upstream.
Eight Mile River: The Eight Mile River is a riverine site connected to the
Connecticut River by Hamburg Cove, in Lyme, CT. The cove is on the east side
of the Connecticut 12.4 rkm from the mouth. The first dam on the Eight Mile is
at Moulson Pond, 1.6 rkm upstream from Hamburg Cove. There is a fish ladder
at Moulson Pond. There is a second dam with a fish ladder an additional 4.8 rkm
further upstream on the east branch of the Eight Mile at Ed Bill’s Pond. Both
species of river herring use the Eight Mile River as spawning habitat.
Wethersfield Cove: Wethersfield Cove is a 27.2 hectare (ha), 5.2 m deep cove
site in Wethersfield, CT. It is connected to the Connecticut River by a 320 m
long, 30 m wide channel. The cove is 72.3 rkm from the mouth of the
Connecticut River. The cove is primarily used by blueback herring, but alewife
can also be found there.
13 Farmington River: The Farmington River is a riverine site that enters the
Connecticut River 87.2 rkm from the mouth. The Farmington is a controlled-flow
river with a hydroelectric dam, Rainbow Dam. The Rainbow dam has a concrete
block-and-weir fish ladder. The river is primarily used by blueback herring, but
alewife can also be found there.
Bride Brook: Bride Brook is a headpond site. A small (mean width ≈ 3 m) stream exits from 29 ha Bride Lake by a small weir board dam. The brook enters Long Island Sound through a 3 m diameter culvert in East Lyme, CT. Bride Lake is 3.5 rkm upstream from
Long Island Sound. Bride Brook is used by alewife.
Poquetanuck Brook: Poquetanuck Brook is a cove site. The small brook is a tributary of the Thames River. The brook empties into Poquetanuck Cove, a shallow (mean depth
< 2 m) tidal cove and marsh that runs into the Thames 21.3 rkm upstream from the mouth. The first dam on the Poquetanuck is 2.7 rkm upstream from the cove and has no fish passage. Alewife use Poquetanuck Brook and cove.
Shetucket River: The Shetucket is a riverine site that joins with the Yantic River to form the Thames River in Norwich, 23.7 rkm upstream from the mouth of the Thames in
New London. The Shetucket is a medium sized river (mean width ≈ 75 m) and the first dam, Greenville Dam, is 3.5 rkm upstream from the confluence. The dam has a fish lift that provides passage for fish migrating upstream. Both species of river herring use the
Shetucket.
14
Figure 1.1 Map of the north shore of Long Island Sound with study sites. Sites are color coded by habitat type: black circles are headpond sites, dark gray circles are coves, and light gray circles are riverine sites. Red dots represent dams. Locations are accompanied by their respective two letter codes. From west to east the sites are Mianus River, Pequonnock River, Housatonic River, Quinnipiac River, Farmington River, Wethersfield Cove, Eight Mile River, Bride Brook, Shetucket River, and Poquetanuck Brook.
15 CHAPTER TWO
Estimating Anadromous River Herring Natal Stream Homing Rates Using Otolith Microchemistry
INTRODUCTION
Natal homing, or philopatry, is a life history characteristic shared by many species of fish. Evidence for spawning site fidelity has been documented across a diverse group of fishes including many species of salmon (Quinn 1993; Quinn et al. 1999), weakfish
Cynoscion regalis (Thorrold et al. 2001), Atlantic bluefin tuna Thunnus thynnus (Rooker et al. 2008), Atlantic cod Gadus morhua (Svedang et al. 2007), Atlantic herring Clupea harengus (Brophy et al. 2006) and American shad Alosa sapidissima (Walther and
Thorrold 2008a; Walther and Thorrold 2008b). Natal fidelity has important ramifications for population connectivity, population persistence, and potential management of fish stocks. Complete or near complete natal fidelity can isolate breeding populations into distinct genetic units, requiring that the breeding population at a site be managed as a distinct biological or population unit. Conversely, lower rates of natal fidelity are characteristic of loosely connected populations that primarily return to specific sites, while allowing for strays to make genetic contributions to other sites. The latter is often termed a metapopulation (Levins 1969; Levins 1970).
Metapopulation dynamics have been shown to increase population resilience to extinction from stochastic threats and contribute to greater temporal population persistence, even when metapopulations are not overly large (Hastings and Harrison
1994). As an example, it has been demonstrated that in species of Pacific salmon, which have some of the highest rates of philopatry discovered, even minor rates of straying can
16 significantly increase mean time until extinction for individual populations (Hill et al.
2002). Some subpopulations often act as sources while others are considered sinks, having a greater propensity for extirpation (Pulliam 1988). In such a scenario, it is vital that source populations be identified and monitored to ensure their persistence and the corresponding possibility of future recolonizations of sink sites in a given metapopulation.
This is the first study that has applied otolith microchemistry to alewife and blueback herring in an effort to provide answers to integral questions about their population dynamics and life history. The two alosine species are collectively referred to as river herring. River herring are anadromous, although alewife also persist in landlocked populations. In response to recent declines in breeding populations across much of the fishes’ range, multiple states have now closed commercial and recreational river herring fisheries. The first moratorium was initiated by Connecticut in 2002 and since then Massachusetts, Rhode Island, and North Carolina have followed suit. In 2007 the National Oceanic and Atmospheric Administration (NOAA) declared alewife and blueback herring Species of Concern under the Endangered Species Act. River herring are jointly managed with a single ‘run’ typically the unit of focus. This management perspective relies upon the untested assumption that river herring home to their natal rivers at high rates and that stock mixing is negligible.
Prior research has suggested that both species of river herring home to their natal rivers at a moderate level but no true estimates have been generated. Analyses of meristic characters (Messieh 1977), physical tagging of spawning adults (Jessop 1994) and limited genetic analyses (Bentzen and Paterson 2005) have provided evidence of
17 philopatry. Additional evidence comes from olfactory choice experiments that showed adult herring preferred water from their natal streams over alternative choices (Thunberg
1971). Research has shown escapement to be directly related to returning year class strength (Jessop 1990) and the stocking of near-ripe adults re-established remnant runs in
Maine (Havey 1961) and the Bronx River, NY (S. Gephard, CDEP; pers. comm.), suggesting that natal fidelity occurs at a moderate level.
That alewife and blueback herring predominately return to their natal locations to spawn as adults is generally accepted, but there have been no precise estimations of the actual degree of homing and straying. This is in large part due to the fragility of juveniles, which makes physical tagging of individuals problematic. A genetic study in
Connecticut exploring the evolutionary origins of landlocked and anadromous alewife concluded that there was little genetic differentiation between the sampled anadromous runs (Palkovacs et al. 2008), however the techniques used did not have the temporal resolution necessary to estimate homing and straying and genetic methods may not be well suited to answering these types of questions (Ferguson and Danzmann 1998). Even with advances in genetic techniques that may allow specific stock identification on finer time scales (e.g. single nucleotide polymorphisms), genetic approaches for estimating river herring natal fidelity to Connecticut tributaries of Long Island Sound may be complicated by active restoration work carried out by fisheries managers. The
Connecticut Department of Environmental Protection (CDEP) annually conducts a successful trap and transport program that augment or seeds struggling and ‘new’ runs of anadromous alewife using pre-spawn individuals captured at sites with stronger runs.
The United States Fish and Wildlife Service has also transported fish from the lower
18 Connecticut River upstream to attempt reestablishment of runs. These relocation activities would likely confound attempts to elucidate homing and straying by river herring. In contrast, trap and transport activities should have a minimal effect on otolith chemistry studies as progeny of transplanted fish would carry the signature of their river of origin, not their parents.
Otolith microchemistry is an approach that has been used to estimate philopatry in other species and could potentially provide estimates of river herring fidelity. Over the past two decades studies have consistently shown that certain elements are incorporated into fish otoliths in concentrations that reflect the chemical composition of the water that the fish inhabited (Bath et al. 2000; Dorval et al. 2007; Elsdon and Gillanders 2002;
Farrell and Campana 1996; Milton and Chenery 2001; Thorrold et al. 1997). It has also been shown that once incorporated into the otolith, elements are metabolically inert
(Campana and Thorrold 2001). These properties enable researchers to examine a diverse range of topics including the movement of individuals (Brazner et al. 2004b; Elsdon and
Gillanders 2005; Kennedy 2002; Limburg 1998a; Secor and Piccoli 1996), natal fidelity
(Rooker et al. 2008; Thorrold et al. 2001; Walther and Thorrold 2008b), potential stock sources (Crook and Gillanders 2006; Hobbs et al. 2005; Zeigler and Whitledge 2010), and population connectivity (Rooker et al. 2008; Thorrold et al. 2001).
Diadromous fish were among the first species to be examined using otolith microchemistry (Limburg 1995; Limburg 1998a; Limburg 2001; Milton et al. 1997;
Quinn et al. 1999; Secor and Piccoli 1996; Thorrold et al. 1998a) and are still common subjects for these studies (Hale and Swearer 2008; Jessop 2003; Morris et al. 2003;
Walther and Thorrold 2008a; Walther and Thorrold 2008b). Otolith microchemistry has
19 been used in retrospective examinations of diadromous fish life history due to the ability of the technique to detect changes in salinity experienced by individuals, largely through changes in Sr concentration (Diouf et al. 2006; Limburg 1995; Limburg 1998a; Secor et al. 1995; Secor and Rooker 2000; Zimmerman Christian 2005). The microchemical demarcation of egress to sea in a life history allows for the elemental signature of freshwater residency (i.e., a natal site) to be isolated, enabling the characterization of chemical signatures for natal sites (Brazner et al. 2004a; Hobbs et al. 2005; Kellison and
Taylor 2007; Milton et al. 1997; Thorrold et al. 1998a; Thorrold et al. 1998b; Tomas et al. 2005b; Walther and Thorrold 2008b; Whitledge et al. 2007). This approach has not been applied to alewife or blueback herring; the capability of otoliths to act as natural tags of natal origin and tracers of individual movements could be a valuable tool to estimate natal fidelity and stock compositions.
The overall objective of this study was to estimate natal fidelity in alewife and blueback herring using otolith microchemistry approaches. In this effort I collected water samples, returning adult river herring, and age 0 herring in 2008 and 2009. The first objective was to quantify what spatial and temporal water chemistry differences might occur among study locations. Age 0 herring were used to examine relationships between water and otolith microchemistry in alewife and blueback herring, determine if differences in incorporation of elements into the otolith existed between the two species, and measure the potential ability to correctly classify known individuals back to their site of collection. Finally, the chemical records from the cores of otoliths from adult fish collected during their spawning migration were used to assess the rate at which fish could be classified back to their collection site.
20
METHODS
Water Collection and Analysis
Samples were collected from nursery areas where age 0 fish were collected or observed in the past at all 10 sites using syringe filtration procedures (Shiller 2003) in order to characterize minor and trace element water chemistry. One sample was collected from each site seasonally in early summer and again in autumn to capture intra-annual variability in elemental composition at the sites. Using a clean polypropylene syringe sample water was passed through a 0.45-µm filter into an acid washed polypropylene sample bottle. Fifteen ml of sample water was passed through the filter as waste followed by an additional 5 ml that was used to rinse the sample bottle. Following the rinsing, 15 ml of water was filtered into the collection bottle. Water samples were stored on ice in a cooler and transported to the Center for Environmental Science and
Engineering (CESE) at the University of Connecticut. Water samples were analyzed using Inductively Coupled Mass Spectrometry (ICPMS) to quantify concentrations of a suite of minor and trace elements including Ca, Sr, Ba, Mg, K, Li, U, Mn, Fe, Ni, Cu, and
Zn. These elements are known to occur in otoliths (Campana 1999) and have been used as elemental tracers of natal habitats in previous studies (Brazner et al. 2004a; Campana et al. 2000; Forrester 2005; Miller et al. 2005; Patterson et al. 2004; Thorrold et al. 2001;
Whitledge et al. 2007) Element concentrations were originally calculated as µg/l. These values were subsequently normalized to Ca and are reported as molar element:Ca ratios
(mmol/mol).
River Herring Collection and Identification
21 Returning adult alewife and blueback herring were collected from March through
June during the springs of 2008 and 2009 (Appendix 1). Five hundred forty-four alewife ranging from 218 to 312 mm were retained. Two hundred forty blueback herring were retained; total lengths ranged from 210 to 307 mm. To obtain a representative temporal sample of returning adults fish were collected from each site every 8-12 days for a total of three to five sampling dates per site. To ensure complete representation of size and age class variation within runs fish were classified by 5-mm size increments during each sampling event and one to two fish per size class were retained for otolith extraction.
Multiple sampling gears were used to capture fish. Gear selection depended upon the habitat type of the sampling area and concentration of fish in that area. Adult fish were collected with dip nets, cast nets, backpack electrofishing, and night-time boat electrofishing. The total length of all retained fish was recorded to the nearest mm and weight to the nearest 0.1 g. Sex was determined by expressing individual fish and gut cavity inspection for sexual organs. Species were identified by external coloration, basic morphology, and for those fish retained for otolith extraction, pigmentation of the peritoneal lining (Collette and Klein-MacPhee 2002). Fifteen-20 scales were removed from the left side of each fish above the lateral line anterior to the dorsal fin and placed in scale envelopes (Davis and Schultz 2009). Fish were euthanized by cold shock, sealed in individual bags and placed on ice. Fish were frozen whole until otoliths were removed several weeks subsequent to collection.
Age 0 fish were sampled in the latter portion of their freshwater residency. By sampling age 0 fish later in the year the amount of time they had spent in the natal environment was maximized, thereby increasing our knowledge of intra-annual variation
22 in site chemistry. Five age 0 fish per site were collected from 6 of the 10 sites in
September - October of 2009 and 8 of the 10 sites in September – October 2009. Age 0 fish were collected using the same technique as adults and were identified as alewife or blueback herring by head morphology and the color of the peritoneal lining (Walsh et al.
2005). Despite multiple efforts, no age 0 fish were collected from the Housatonic River or the Shetucket River in 2008 and Poquetanuck Brook and the Farmington River in either year.
Otolith Preparation and Analysis
Both sagittal otoliths were removed from each fish using nonmetallic forceps, thoroughly rinsed in reverse osmosis de-ionized (DI) water to remove any organic materials and stored in capped polyethylene vials until otolith microchemistry preparation.
One otolith from each adult fish was chosen randomly and prepared for analysis.
The selected otolith was embedded in Epo-Fix epoxy (Struers, Inc.) and sectioned in the transverse plane using an ISOMET low-speed saw. Each otolith was cut twice, creating a section of otolith with the core at the center. Likewise, one otolith from each age 0 fish was randomly selected and prepared. Age 0 otoliths were placed in thermoplastic glue and ground in the frontal plane. All otoliths were ground evenly with multiple grades of silicon carbide (SiC) wet/dry sandpaper and polished with 3 µm lapping film to reveal growth increments and create a polished surface prior to ablation. Prepared otoliths were affixed to acid-washed glass slides using double-sided tape (3M), placed in polypropylene petri dishes and ultrasonically cleaned for 5 minutes in ultrapure water
(Fisher Scientific). Samples were then dried in a Class 100 laminar flow hood. After
23 drying the samples were sealed and placed in a container for transport to the Great Lakes
Institute for Environmental Research (GLIER) at the University of Windsor, Canada.
Adult otolith thin sections and juvenile whole otoliths were analyzed for 7Li,
25Mg, 39K, 43Ca, 44Ca, 55Mn, 57Fe, 60Ni, 62Ni, 63Cu, 65Cu, 66Zn, 67Zn, 86Sr, 88Sr,
118Sn, 120Sn, 138Ba, and 238U, using a Finnegan Thermo Elemental X7 inductively coupled mass spectrometer (ICPMS) coupled with a Quantronix Integra C® femtosecond
(fs) laser. Transects were ablated from the dorsal side of the otolith to the ventral edge passing through the core (beam diameter = 24 µm, laser pulse rate = 100 Hz, laser energy level = 0.026 mJ/pulse, wavelenghth 785 nm, dwell time = 253 ms). A National Institute of Standards and Technology (NIST) 610 standard was ablated every 5-17 samples to adjust for possible instrument drift. Each sample analysis was preceded by a gas blank measurement. Isotopic counts were converted to elemental concentrations (µg/g) after correction for gas blank, matrix, and drift effects. Element: Ca ratios were averaged over the period an adult fish spent in freshwater or the entire age 0 otolith. In adult otoliths the transitions from the natal area to saltwater were isolated by examining the Sr:Ca and
Ba:Ca levels during the first year of a fish’s life. In the past transitions to saltwater have been identified by rapid changes in ratio levels (Limburg 2001; Secor 1992) which were apparent in the otoliths of most fish examined. In cases where no transition was observed the ablated otolith was examine under a compound microscope to discover whether the core was removed during grinding or missed during ablation. If this was the case, the otolith and corresponding fish were removed from the study. After removing these otolith 498 fish remained for analysis, 333 of these were alewife and 165 blueback herring. I further discriminated natal site selection by calculating the 95th percentile
24 value of Sr:Ca and 5th percentile value of Ba:Ca from the age 0 fish that were known to inhabit fresh water (Lochet et al. 2008). These values provided bench marks for freshwater habitation and transitions form these levels to elevated Sr and depressed Ba environments were assumed to be transitions to saltwater. Averages were then normalized to Ca, which was considered an internal pseudostandard (Bickford and
Hannigan 2005; Ludsin et al. 2006; Whitledge et al. 2007). All otolith microchemistry data are reported as molar element:Ca ratios (µmol/mol).
Data Analysis
Both univariate and multivariate approaches were used to assess differences in trace element concentrations among collection sites. All water and otolith concentrations were log10 transformed to address concerns about normality. In most cases Sr:Ca and
Ba:Ca still violated assumptions of normality after transformation. For all tests a P value of ≤0.05 was considered significant.
Prior to examining otolith chemistry it was necessary to characterize the differences in mean water chemistry at the sites during the two years of the study. A two- way analysis of variance (ANOVA) with an interaction term combining site and year was used to assess inter-annual variability in the mean water chemistry among sites. Mean element:Ca at the individual for both years of the study were compared using one-way
ANOVAs followed by Tukey’s Honestly Significant Difference (HSD) test.
Since this was the first otolith microchemistry study to examine alewife or blueback herring it was necessary to determine whether the two species assimilated trace and minor elements from the water at similar levels. To assess the effect of species on
25 differences in age 0 element:Ca ratios ANCOVA tests were run with Tukey’s adjustment; year specific mean water element:Ca from the collection sites were used as covariates.
For an element:Ca ratio to aid in natal site identification it must vary between sites and this variability must be reflected in the otolith of the fish inhabiting that site.
Elements that did not meet both of these qualifications were removed from further consideration. Data from the two years of age-0 fish collected were pooled to meet sample size requirements and differences in mean element:Ca among sites were identified using one-way ANOVA with Tukey’s HSD test. Differences in adult ratios were evaluated in identical fashion. The relationship between corresponding year mean site water chemistry and individual otolith chemistry was assessed by linear regression for each element.
To characterize site specific signatures a number of multivariate techniques were used. Only element:Ca ratios that varied by site and were included in multivariate analysis only included element:Ca ratios that both varied by site and had a significant relationship between water and otolith abundance. Further, sites represented by inadequate sample sizes were removed prior to analysis (McGarigal et al. 2000).
Minimum sample size was defined as,
, where N was the number of samples, P represented the variables in group 1, and M the number of variables in group 2. Sites were characterized in multivariate space using both multivariate analysis of variance (MANOVA) and canonical analysis of discrimination
(PROC CANDISC, SAS 9.2). Pillai’s trace statistic was used to assess significant differences in multivariate element signatures for the study sites. Classifications of
26 individuals were made through quadratic discriminant function analysis with a leave-one- out jackknife procedure (PROC DISCRIM, SAS 9.2). Differences among sites were visualized by plotting collection site group means with 95% confidence ellipses around the centroid in SYSTAT 13.
Classification procedures were evaluated in several ways. Discriminatory performance was examined via the proportion of among-group variation explained by the eigenvalue of each canonical variate. Performance was also evaluated using the squared
2 canonical correlation (Rc ), which represents the amount of explained dispersion on a canonical variate that is attributable to differences between the examined groups
(McGarigal et al. 2000). Discriminant function analysis accuracy was also assessed using a randomization method (White and Ruttenberg 2007). A bootstrap procedure generated
5,000 randomizations of the otolith data to estimate the random chance of success and determine if the mean rates of reclassification were significant.
Evidence of different movement patterns among individual fish were examined by inspection of otolith Sr:Ca and Ba:Ca trends across an ablation transect of the otolith.
Element concentrations were plotted beginning at the core and proceeding outward to the edge of the otolith. Rapid changes in Sr:Ca greater than 1.5X in magnitude (personal observation) as well as periods where Sr:Ca values were sustained at near seawater levels (1,500 – 2,500 µmol/mol) only to revert to freshwater levels (200 – 1,000
µmol/mol) were interpreted as transitions among habitats, such as from a coastal pond to a downstream tidal estuary (Kennedy 2002; Limburg 1995; Limburg 1998a; Limburg
2001; Morris et al. 2003; Secor et al. 1995; Walther and Thorrold 2006a).
27 RESULTS
Water chemistry
Element:Ca ratios for Mg, K, Mn, Fe, Zn, Sr, and Ba varied among sites.
However only variability in Sr:Ca and Ba:Ca produced corresponding differences in otolith chemistry among sites, so Mg, K, Mn, Fe, and Zn were not considered further.
Sr:Ca and Ba:Ca were not significantly different between the two years (two-way
ANOVAs; Sr: F = 0.85; df = 1, 20; P < 0.3668, Ba: F = 3.41; df = 1, 20; P < 0.0798 ).
Differences in mean Sr:Ca among the study sites did not vary significantly between 2008 and 2009 (SITE*YEAR interaction term ; F = 0.15; df = 9, 20; P = 0.9996). Sr:Ca in the water did differ significantly by site (two-way ANOVA; F = 10.48; df = 9, 20; P <
0.0001). Poquetanuck Brook had Sr compared to most other sites, while the Quinnipiac
River and Housatonic River had lower mean Sr:Ca than several sites (Fig. 2.1a).
Differences in mean Ba:Ca among the study sites did not vary significantly between 2008 and 2009 (SITE*YEAR interaction term, F = 0.45; df = 9, 20; P = 0.8934). There were differences in mean Ba:Ca among sites (two-way ANOVA; F = 6.74; df = 9, 20; P =
0.0002). The Farmington River and the Quinnipiac River had the highest mean Ba and, while still similar to 3 other sites, the Housatonic River had the lowest. (Fig. 2.1b)
Age 0 otolith chemistry
The relationship between mean water Sr:Ca and Sr:Ca in the otoliths of individual fish differed significantly between age 0 alewives and blueback herring (ANCOVA; F =
51.70; df = 1, 64; P < 0.0001). Blueback herring otoliths had lower otolith Sr:Ca for a given water Sr:Ca than alewives (Figs 2.2a and 2.3a). The relationship between water
28 Ba:Ca and Ba:Ca within individual otoliths did not differ between species (F = 0.23; df =
1, 64; P = 0.6322). The Sr:Ca values (Fig. 2.2a) and Ba:Ca (Fig.2.2b) values from alewife otoliths reflected the mean water Sr:Ca and Ba:Ca values from their collection sites (Sr: r2 = 0.7070; P < 0.0001 and Ba: r2 = 0.2172; P = 0.0028). The Sr:Ca water to otolith regression explained more variation than the Ba:Ca regression (Figs. 2.2a and
2.2b). In blueback herring otoliths Sr:Ca (Fig. 2.3a) and Ba:Ca (Fig. 2.3b) were significantly related to the chemistry of the water they were collected from (Sr: r2 =
0.7560; P < 0.0001 and Ba: r2 = 0.3070; P = 0.0022). As with alewife, the Sr:Ca water to otolith regression for blueback herring explained more variation than Ba:Ca (Figs. 2.3a and 2.3b). The difference in the incorporation of Sr into the otoliths between species necessitated that the two species be analyzed separately in subsequent analyses.
Ba:Ca and Sr:Ca in age 0 alewife otoliths varied among sites and allowed for high reclassification rates at some sites. Age 0 fish collected from the Housatonic River, the
Mianus River, and the Shetucket River were removed prior to multivariate analysis because of inadequate sample sizes at those sites. Multivariate analysis of variance indicated that fish from the 4 remaining alewife collection sites (Bride, Eightmile,
Quinnipiac and Pequonnock) had significantly different otolith chemistry signatures
(Pillai’s Trace Statistic: F = 17.55, df = 6, 54, P < 0.0001). Canonical scores for individuals suggested that unique chemical signatures existed, but not for all sites; the
Eightmile River was not distinct from other collection areas (Fig. 2.4a). The first canonical function (CAN 1) explained 77% of the total dispersion in the data, and 79% of the variation of the function was attributed to differences among groups. Both otolith
Sr:Ca and Ba:Ca were correlated with CAN 1 (correlation coefficients: Sr:Ca = 0.97;
29 Ba:Ca = 0.64; P ≤ 0.0001). The second canonical function (CAN 2) explained less of the dispersion in the data (23%) and differences among sites accounted for 53% of the canonical variation. Only otolith Ba:Ca values were correlated with CAN 2 (correlation coefficient = 0.77, P < 0.0001). Numerically CAN 2 does not appear as important as
CAN 1 but visually it is apparent that CAN 2 contributes to site discrimination, especially between Pequonnock and Quinnipiac (Fig. 2.4). Quadratic discriminant function analysis
(QDFA) was conducted using Sr:Ca and Ba:Ca since both elements contributed significantly to discriminatory power. Results from the QDFA employing a leave-one- out jackknife procedure suggested that classification back to site-of-capture was possible in most instances (Table 2.1); individuals were classified with 50-100% accuracy. All of the QDFA reclassification rates were higher than what the randomization procedure suggested was expected from chance alone (Null reclassification rate = 24.45%; SD =
0.10). The mean reclassification rate obtained through QDFA was 77.5%, which was comparable to the mean reclassification rate generated by the randomization procedure
(mean reclassification rate = 80.65%; P = 0.0002).
There was little variation in age 0 blueback herring otolith Sr:Ca and Ba:Ca among sites; reclassification rates were uniformly low. Juvenile blueback herring inhabit fewer aquatic systems in Connecticut and were collected from 6 locations. However, in 3 of those rivers (Housatonic River, Quinnipiac River, and Shetucket River) low sample sizes necessitated their removal from multivariate analyses, leaving three collection sites
(Eightmile River, Wethersfield Cove, and Mianus River) with adequate samples.
MANOVA results indicated that there were not significant differences in age 0 blueback herring Sr:Ca and Ba:Ca from the remaining sites (Pillai’s Trace Statistic: F = 2.17, df =
30 4, 38, P < 0.0905). Otolith Ba:Ca was correlated (correlation coefficient = 0.97, P <
0.0001) with CAN 1, which explained 65% of the total dispersion in the data. However, differences in site means accounted for 23% of the total canonical variation, meaning that
CAN 1 did a poor overall job of discriminating among collection sites. The second canonical variate was correlated with otolith Sr:Ca (correlation coefficient = 0.99, P <
0.0001) and performed similarly as among group differences explained only 19% of the total canonical variation. As a result, QDFA jackknife classification accuracy for age 0 blueback herring to their site of collection was low (20-57%). The randomization procedure confirmed that classification was not reliable (Null reclassification rate =
32.83%; SD = 12.41%). All of the reclassification rates generated by the QDFA fell within the 95% confidence limits of the null reclassification estimate. The mean reclassification success rate generated by the randomization procedure (36%) was comparable to the mean rate of the QDFA (39.05) but was not significantly different from the null reclassification rate (P = 0.4570).
Adult otolith chemistry
Adult alewife otolith chemistry differed by site but there was widespread overlap among sites which created highly variable reclassification rates. Returning adult alewife were collected from all 10 sites, although less than 10 fish were collected from Wethersfield
Cove and the Farmington River. Consequently these two sites were removed from multivariate analysis. Both Sr:Ca and Ba:Ca differed among collection sites (one-way
ANOVAs Sr: F = 41.73, df = 7, 325, P < 0.0001; Ba: F = 14.88, df = 7, 325, P < 0.0001).
Multivariate analysis using both ratios indicated differences between sites (Pillai’s Trace
Statistic: F = 27.06; df = 14, 650; P < 0.0001). Visual inspection of the plot of canonical
31 variates indicated that fish within all sites were dispersed but that some signatures were distinct (Fig. 2.5). The 95% confidence ellipses of the group means suggest separation of signatures for Poquetanuck Brook, Housatonic River, Pequonnock River, and Bride
Brook. The signals for Quinnipiac River, Mianus River, Shetucket River, and Eightmile
River either overlapped or were relatively more dispersed. The first canonical variate explained 76% of the total dispersion in the data. Group differences accounted for 50% of the total variation within CAN 1. Adult alewife otolith Sr:Ca levels were correlated with CAN 1 (correlation coefficient = 0.96; P < 0.0001). The remaining dispersion in the data was explained by CAN 2. Less of the variation in CAN 2 (24%) was explained by differences among sites than CAN 1. Adult alewife otolith Ba:Ca levels were positively correlated to CAN 2 (correlation coefficient = 0.99; P < 0.0001) and otolith Sr:Ca levels were negatively correlated to CAN 2 (correlation coefficient = -0.30; P < 0.0001). Adult alewife Sr:Ca and Ba:Ca were included in a QDFA using the jackknife leave-one-out reclassification procedure. Reclassification of fish to their site of collection was variable; rates ranged between 10 - 85% (Table 2.2). Poquetanuck Brook, Bride Brook and
Housatonic River, which all had isolated and cohesive signatures, returned higher (64-
85%) reclassification rates. Locations whose signatures largely overlapped or where there was large variation in the individuals collected at that site (Shetucket River,
Quinnipiac River, and Eightmile River) had lower rates (10 - 20%) of reclassification.
The results of the randomization analysis indicated that the classifications from the adult alewife QDFA were accurate. The estimated rate of successful reclassification due to chance alone was equivalent to the results for the 3 sites with the lowest reclassification rates (Null reclassification rate = 12%; SD = 2.48%). The overall mean QDFA
32 reclassification rate (44.66%) compared favorably with the significant mean obtained by the randomization routine (Mean reclassification rate = 39.64%; P = 0.0002).
Blueback herring otolith chemistry varied by site but differences were largely restricted to one site, limiting the functionality of classification procedure. As expected, returning adult blueback herring were collected at fewer sites than alewife and were collected at only 5 locations. Only one individual was collected from the Shetucket River, hence the site was removed from multivariate analyses. Otolith Sr:Ca and Ba:Ca values from Quinnipiac River, Eightmile River, Farmington River, and Wethersfield Cove were significantly different among sites (one-way ANOVAs Sr: F = 10.48, df = 3, 160, P <
0.0001; Ba: F = 3.10, df = 3, 160, P < 0.0285). Multivariate analysis based upon the two ratios also indicated differences among sites (Pillai’s Trace Statistic: F = 5.53; df = 6,
320; P < 0.0001). Canonical plots suggested that the only distinct signature was for
Quinnipiac River, which separated on canonical variate 1 (Fig. 2.6). The first canonical variate explained 89% of the dispersion in the data, but only 17% of the variation within
CAN1 could be attributed to differences in mean otolith Sr:Ca and Ba:Ca among sites.
Adult blueback herring otolith Sr:Ca was positively correlated with CAN 1 (correlation coefficient = 0.99; P < 0.0001) and otolith Ba:Ca was negatively correlated with CAN 1
(correlation coefficient = -0.48; P < 0.0001). CAN 2 made a negligible contribution to discrimination among sites; it explained 11% of the variation with differences between groups explaining 2% of the within variate dispersion. Adult blueback herring otolith
Ba:Ca was correlated to CAN 2 (correlation coefficient = -0.88; P < 0.0001).
Reclassification of individuals back to their site of capture was low for the three
Connecticut River tributary sites (Farmington River, Wethersfield Cove, Eightmile
33 River), and ranged between 15-33%. Quinnipiac River, however, had a reclassification rate of 81%. This rate was comparable to that of the most distinct alewife site,
Poquetanuck Brook, which had a reclassification rate of 85%. Randomization analysis results suggested that some of the blueback QDFA classifications were not better than chance. The null reclassification rate from the randomization analysis was 25% (SD =
4.2%). The reclassification rates for the three Connecticut River sites fall within the 95% confidence limits for this estimate. The mean reclassification rate obtained by QDFA
(39.89%) was comparable to the significant mean estimated by the randomization procedure (mean reclassification rate = 35.37%, P = 0.0068).
Early life history movements
Otolith records of the early life history of individual fish were largely suggestive of occupancy in a discrete habitat (i.e. minimal variation in Sr:Ca and Ba:Ca) until emigration from natal sites, but a subset of fish did not conform to this pattern. Otolith chemistry from age 0 river herring collected in freshwater and from the portions of adult transects corresponding to marine residency (i.e. near the edge of the otolith) indicated that Sr:Ca values reflective of saltwater occupancy were above 2,000 µmol/mol while concentrations in freshwater were typically below 1000 µmol/mol. Ba:Ca patterns were usually the inverse of Sr:Ca but sometimes Ba:Ca remained elevated even when Sr:Ca reached levels indicative of high salinity environments. Ba:Ca ratios above 3 µmol/mol were typical of freshwater residency while values below 2 were indicative of marine residency. Most fish displayed patterns that suggested direct emigration from freshwater natal habitats to the marine environment (Figs. 2.7a and 2.7b). Records from age 0 fish sampled from headponds were assumed to reflect temporal rather than spatial variations
34 in element:Ca ratios because once juveniles left these sites re-entry into the nursery was impeded (i.e. high head dams, Figure 2.7b). Inspection of the individual otolith microchemistry transects of age 0 alewife and blueback herring from non-headpond locations sometimes revealed patterns that suggested spatial rather than temporal variation, although variation could have theoretically occurred from shifts in the position of the salt wedge at river sites closer to Long Island Sound. These patterns were typified by periods where the magnitude of Sr:Ca would rapidly double or decrease by half. In many instances Sr:Ca levels would approach or equal what was typical of saltwater environments only to return to levels representative of freshwaters (Figs. 2.7c and 2.7d).
This indicated that at least some individuals did not emigrate from nursery areas to the ocean in a single downstream movement. Otolith chemistry from the early life of returning adults also indicated that at age 0 some individuals made transitions between environments with different salinities (Figs. 2.7e and 2.7f), particularly in systems where movement between different habitats was unrestricted, such as tributaries of the
Connecticut and other riverine sites. Inspection of the early life history of all ablated fish showed that approximately 15% of fish did not migrate directly from their natal site but instead appeared to move between sites or exited and re-entered freshwater habitats.
DISCUSSION
There were significant differences in the water chemistry at the study sites and in the otoliths of age 0 fish collected from these sites, but the differences did not allow complete resolution of chemical signatures among sites. Several sites had similar multivariate signatures, presumably because of their close proximity and geologic
35 similarities among watersheds. Otolith chemistry did allow for the accurate reclassification of adult fish to a few chemically distinct collection locations, but again was not reliable for most sites. Unlike other sympatric anadromous species, particularly striped bass Morone saxatilis and American shad, which ascend only larger watersheds to reproduce, river herring and in particular alewife often return to closely spaced, even neighboring, watersheds of varied size along the Atlantic coast. The difficulty observed in reclassifying individuals back to sites was probably linked to the relatively small spatial scale of our study, although resolution at this small spatial scale, informative to potential metapopulation dynamics, is precisely the information needed to inform management and restoration activities.
Reclassification of age 0 alewives to their collection location was partially successful while reclassification of age 0 blueback herring was not. While sample sizes were low, reclassification rates for sites that were not tributaries of larger systems (Bride
Brook, Pequonnock River, Quinnipiac River) suggest that otolith chemistry techniques can be used to discriminate the natal origins of alewife. Jackknife reclassifications of adult alewife to chemically distinct sites, presumed to be the natal nurseries of these fish, ranged between 65-83%. These estimates of homing are consistent with estimates from preliminary genetic studies (Bentzen and Paterson 2005), meristic character analysis
(Messieh 1977), and physical tagging results (Jessop 1994). Evaluating the generality of homing and straying estimates among sites and establishing estimates of population connectivity were not possible.
Typically reclassification rates of known-origin individuals are greater than the rates seen in this study (Brazner et al. 2004a; Thorrold et al. 1998a; Walther and Thorrold
36 2008b; Zeigler and Whitledge 2010). Initial concerns about low within-group sample size (Williams and Titus 1988) were reduced by the significant results of the randomization procedure. The observed reduced reclassification rates in this study were seemingly a result of two factors. The analysis was challenged in large part because of the homogeneous trace element water chemistry. Only two chemical markers (Sr:Ca and
Ba:Ca) had significant differences between the water bodies sampled and were reflected in the otoliths of age 0 fish. These markers separated age 0 alewife sites adequately, but did not differentiate the reduced set of three age 0 blueback herring sampling locations despite separation between Mianus River and the other two sites (Eightmile River and
Wethersfield Cove) which are both tributaries of the Connecticut River. This result was not unexpected given that analysis of water samples indicated that these three sites had equivalent water Sr:Ca and Ba:Ca.
Another factor contributing to the inability to reclassify known-origin age 0 individuals back to some sites was the apparent mobility of age 0 fish in nursery systems.
Previous studies have documented age 1 river herring in estuaries and rivers that appeared to have never emigrated to the open ocean (Limburg 1998a; Marcy 1969) but the general expectation of age 0 movement was that individuals remained in discrete nursery areas until emigration was triggered and that the majority of age 0 fish emigrated in large waves (Gahagan et al. 2010b; Kissil 1974; Loesch 1987; Yako et al. 2002). The otolith transects of individual fish examined in this study indicated that age 0 fish were more mobile than has been previously suggested. Sr:Ca ratios appeared to indicate salinity transitions (Kennedy 2002; Limburg 1995; Limburg 1998a; Secor et al. 1995);
Ba:Ca was also informative of salinity (Elsdon and Gillanders 2005) but may be
37 complicated by more complex gradients in estuaries (Coffey et al. 1997; Shaw et al.
1998; Stecherlii and Kogut 1999). Different movement patterns were observed among individual fish. Stair-case increases in Sr:Ca (Fig. 2.7 c and d) suggested gradual down- stream movement towards saltwater as fish develop. Some individuals (Fig. 2.7b) likely encountered higher salinity and subsequently moved back to freshwater. Another pattern
(Fig. 2.7a) appeared to be movement from freshwater to an elevated salinity environment followed by a gradual movement towards slightly lower salinity, perhaps an estuary.
Otolith Ba:Ca in adult fish always decreased at the presumed entry into the marine environment but did not always appear to reflect environmental transitions as well as
Sr:Ca during the period of freshwater residency (Figs. 2.7 a and c).
The rate and variety of movement witnessed in age 0 river herring has not been documented previously and made collection and designation of ‘known’ location fish, and establishment of otolith chemistry signatures for those sites, more complicated than was anticipated. In some sites no age 0 fish were collected, even though adults were known to have been present and spawning, and in others age 0 were difficult to collect.
This was especially true for blueback herring which were more frequently collected from lotic systems where a high degree of mobility was possible. The issue of high mobility at early life stages should not be thought of as solely an issue for reclassification of age 0 fish as it can also hinder the ability to designate ‘natal’ signatures in the otolith cores of adult fish. In a management context, the possibility that stock mixing begins to occur prior to age 0 migration from larger natal systems may preclude desires to manage at the tributary or stream ‘run’ scale.
38 Age 0 alewife were collected from sites whose water chemistry featured significant differences in both Sr:Ca and Ba:Ca and were successfully classified back to their natal areas at relatively high rates. In contrast to blueback herring, alewife typically spawn in lentic environments such as coastal and river headwater ponds and impoundments (Collette and Klein-MacPhee 2002; Loesch 1987). In these circumstances collecting known-origin age 0 fish was straightforward and variability in the chemical signatures of these sites represented temporal rather than spatial variability. The defined space of these ponded nursery environments also appeared to produce more cohesive otolith chemistry signatures when compared to larger open systems. This was supported by the low reclassification rate of fish from the Eightmile River, which is connected to the tidal lower Connecticut River. The successful reclassification of some of the age 0 alewife demonstrated that despite issues with the mobility of individuals and relatively homogeneous water chemistry between sites, otolith chemistry could be used to discern the origins of river herring at some of the sites.
Reclassification of returning adult individuals was variable for alewife and blueback herring. There were multiple sites for both species of fish where reclassification was no better than would be expected from random assignment. For adult alewife, all three sites that did not exceed this null reclassification rate were riverine in nature and the otolith signatures of individuals collected at those sites were widely dispersed in multivariate space. A high degree of variability in the otolith signatures from a site could be caused by a prevalence of individuals that had strayed to that site, but could also be caused by misclassification due to similar otolith signatures caused by homogeneous water chemistry. Further, the mobility of those fish in the earliest life
39 stages can make retrieval of a distinct natal chemical signature at the otolith core difficult if fish spent only a short period of time near the location of birth. The otolith chemistry from three collection locations (Poquetanuck Brook, Bride Brook, and the Housatonic
River) produced distinct signatures and minimal dispersion among individuals in multivariate space. Reclassification rates at three of the four blueback herring sites were not higher than random. The Farmington River, Wethersfield Cove and the Eightmile
River are all tributaries of the Connecticut River and it is possible that in conjunction with similar water chemistry there may be higher straying among these three sites.
Blueback herring are batch spawners (Richkus and Dinardo 1984) and the incidence of repeated spawning events appears to increase moving northwards in the species’ range
(Greene et al. 2009). It is possible that fish collected at locations up-river in the
Connecticut River watershed may have already spawned once, perhaps at their natal site downstream and have moved elsewhere for a second spawning event. It appears that otolith microchemistry will not provide the resolution needed to address questions such as the possibility of within watershed movements between batch spawning events.
There were two sites with distinct water chemistry that may have in turn produced distinct signatures in the otoliths of adult fish captured there. Poquetanuck Brook was likely chemically distinct from the other sites due to high salinity, which created higher water Sr:Ca and lower water Ba:Ca and appeared to be corroborated in the juvenile- period otolith chemistry of most fish captured there. Poquetanuck Brook grades into
Poquetanuck Cove, which is a shallow (depth < 2m in most areas) tidal cove connected to the lower Thames River. The cove is very well mixed by tidal actions and has elevated levels of salinity regardless of tide level (Loesch and Lund 1977). Returning adults
40 collected from Poquetanuck Brook often had core Sr:Ca values higher (>3,000 µmol/mol) than those portions of the otolith corresponding to marine residency. These Sr:Ca values exceeded the mean levels in fish collected from other sites (Appendix II). The distinct chemical signal provided a reclassification rate (85%) that may accurately reflect alewife natal fidelity, although there may have been other unsampled sites with similar chemical signals from which fish could have originated. The Quinnipiac River was not as unique as Poquetanuck Brook but stood out from other the other sites where spawning blueback herring were collected and produced an estimated 81% reclassification rate. The reduced number of sites (and runs) of blueback herring aided the ability to separate Quinnipiac
River in multivariate space, as sites with overlapping chemistry only supported alewife runs during the two years of sampling. The observed difference in results for the two species from the same site clearly illustrated the effect of site selection in otolith chemistry studies. A reduction in the number of sites to be resolved in multivariate analyses can alter reclassification percentages. Non-objective approaches such as choosing a reduced suite of sites, removing sites with poor performance from analysis, or picking ideal sites based upon preliminary water chemistry analyses will likely boost the performance of reclassification procedures but may lead to inflated rates of homing if unsampled sites are likely contributors of strays. This study examined a number of sites but the presence of many spawning sites, particularly for alewife, makes complete coverage a near impossibility. The prospect of future recoveries of previously extirpated runs will decrease the possibility of sampling all the existent runs even further.
The two rates produced that may be more accurate of true fidelity were similar, alewife 85% and blueback herring 81%, but only represent two sites and a single datum
41 for each species. Because these rates were estimated without the benefit of known chemistry signatures from specific years they are not homing estimates and should be used cautiously. On the other hand these rates are within the range of estimates derived from other methods. Jessop (1994) tagged spawning adults in the St. John River, New
Brunswick, Canada and recaptured individuals that survived to spawn in subsequent years. He observed that adult herring returned not only to natal rivers but to specific areas with those systems at rates of 63-97%. Messieh (1977) employed a discriminant function analysis of the meristic characters of alewife in the St. John River and produced a wide range of homing estimates, 20.8 – 82.6%, across sites (mean = 45.82; SE = 8.55).
Preliminary genetic analysis of tributary runs in the St. Croix River, Maine, USA and
New Brunswick indicated that alewife were capable of fine-scale philopatry (Bentzen and
Paterson 2005) but a genetic study in eastern Connecticut concluded that there was significant gene flow between populations and that it did not diminish across the spatial scale (80 km) of the study (Palkovacs et al. 2008). Compared to other species of fish, philopatry estimates in the low 80% range indicates an inherent proclivity to spawn at natal locations but the rates are less than estimates for many salmon species (Quinn 1993;
Quinn et al. 1999).
The reclassification rates for adult river herring are also less than the homing rates observed for another alosine, the American shad. Trap and transport of pre-spawn adults to restored or soon to be restored natal habitats has been a successful strategy in
American shad management (Greene et al. 2009) and chemical tags created in hatcheries have indicated that adults that return to newly restored habitat are overwhelmingly composed of fish that were stocked there as larvae (Hendricks et al. 2002). Examination
42 of natural tags has shown that shad can have very high fidelity to natal sites at the watershed level but straying increases at the level of within watershed tributaries
(Walther and Thorrold 2008b). Recent research on the trap and transport stocking of river herring suggests that this method of run augmentation may be less successful than previously thought (Frank et al. 2009; Smith et al. 2009). Trap and transport may also have negative effects on the run from which fish are taken beyond reducing the numbers of fish that spawn at a site. Fish held within a trap may spawn in the trap, suffer scale loss, experience stress from being sequestered, and be harassed, wounded, or killed by predators while trapped (Dalton et al. 2009; Gahagan pers. obs.). There is no research on the potential effects trap and transport may have on the host run, but if benefits are reduced by ‘fallback’ (Frank et al. 2009) and straying occurs at a rate that is adequate to repopulate opened runs on a comparable time scale then less active management of runs may be prudent.
It is important to note that the reclassification rates presented here should not be interpreted as true estimates of natal homing. In this study no age 0 fish were available or collected prior to our sampling to generate an ‘atlas’ of known chemical signatures from sites and create statistical training sets to discriminate the origins of adult year classes returning to spawn in 2008 and 2009. It was therefore impossible to know whether fish classified as strays were spawned at another location or represented variability in site chemistry across years, although chemistry was stable during the two years of this study.
This research demonstrated that age 0 and adult river herring could be reclassified to the site of capture at sites that were geochemically distinct. However the observed homogeneity of water chemistry in closely spaced watersheds and possible difficulties in
43 sampling ‘known’ age 0 fish due to early life history movements from nursery areas suggest that it may be difficult to use geochemical methods to resolve natal origins among closely spaced river herring runs. Despite these issues the technique may be useful for estimating homing to particular sites with unique chemical signatures such as
Poquetanuck Brook.. Further discrimination may be possible in future studies if isotopic markers (e.g. δ18 O, δ13 C, 87Sr/86Sr) are also employed. Future research into anadromous river herring philopatry may be more effectively accomplished through alternate techniques. Advancements in genetic analysis, new physical tagging methods that may work on fragile river herring juveniles, chemical batch marking, or a combination of several techniques could be used to better explore homing in alewife and blueback herring.
44 Table 2.1 Results of quadratic discriminant function analysis with jackknife procedure for age 0 alewife. The number of fish analyzed per site is the total for each row. Classification accuracy back to site of collection was based upon otolith Sr:Ca and Ba:Ca. Source Assigned Site % Correct Site Bride Eightmile Pequonnock Quinnipiac Bride 9 1 0 0 90 Eightmile 1 2 0 1 50 Pequonnock 1 2 7 0 70 Quinnipiac 0 0 0 7 100
45 Table 2.2 Results of quadratic discriminant function analysis with jackknife procedure for adult alewife. The number of fish analyzed per site is the total for each row. Reclassification back to site of collection was based upon otolith Sr:Ca and Ba:Ca. (Site codes: BB = Bride Brook; EM = Eightmile River; HR = Housatonic River; MR = Mianus River; PB = Poquetanuck Brook; PR = Pequonnock River; QR = Quinnipiac River; SH = Shetucket River) Source Assigned Site % Site BB EM HR MR PB PR QR SH Correct BB 32 2 1 5 5 5 0 0 64 EM 8 7 4 5 6 12 0 0 17 HR 0 0 26 1 1 8 0 4 65 MR 12 2 0 22 4 6 2 1 45 PB 0 1 1 0 41 0 0 5 85 PR 1 2 8 5 3 20 0 0 51 QR 4 2 3 12 8 6 9 0 20 SH 2 3 2 1 10 1 0 2 10
46 Table 2.3 Results of quadratic discriminant function analysis with jackknife procedure for adult blueback herring. The number of fish analyzed per site is the total for each row. Reclassification back to site of collection was based upon otolith Sr:Ca and Ba:Ca. Source Assigned Site % Site Eightmile Farmington Quinnipiac Wethersfield Reclassified Eightmile 6 9 13 13 15 Farmington 4 12 9 13 32 Quinnipiac 1 3 29 3 81 Wethersfield 8 17 8 16 33
47 (a)
(b)
Figure 2.1 a Mean water Sr:Ca (SE) and b mean water Ba:Ca (SE) for the 10 collection sites Bars represent the mean element:Ca ratio based upon samples from both years. In each panel means that are marked with the same letter are not significantly different (ANOVA with Tukey’s HSD test on log transformed values, P < 0.05).
48 (a)
(b)
Figure 2.2 a Linear regression of individual age 0 alewife otolith Sr:Ca on mean water Sr:Ca and b Linear regression of individual age 0 alewife otolith Ba:Ca on mean water Ba:Ca. All element:Ca ratios are based upon the freshwater residency period of the fish. All data are log-transformed.
49 (a)
(b)
Figure 2.3 a Linear regression of individual age 0 blueback herring otolith Sr:Ca on mean water Sr:Ca and b Linear regression of individual age 0 blueback herring otolith Ba:Ca on mean water Ba:Ca. All data are log-transformed.
50
Figure 2.4 Plot of Canonical Variates 1 and 2 created through quadratic discriminant function analysis including age 0 alewife Sr:Ca and Ba:Ca.
51
Figure 2.5 Plot of Canonical Variates 1 and 2 created through quadratic discriminant function analysis including adult alewife otolith Sr:Ca and Ba:Ca. Points represent individuals collected from the indicated sites and ovals are 95% confidence ellipses around group centroids generated from the samples.
52
Figure 2.6 Plot of Canonical Variates 1 and 2 created through quadratic discriminant function analysis including adult blueback herring otolith Sr:Ca and Ba:Ca. Points represent individuals collected from the indicated sites and ovals are 95% confidence ellipses around group centroids generated from the samples.
53
Figure 2.7 Representative Sr:Ca and Ba:Ca transects of adult direct migrations (a and b), age 0 indirect migrations (c and d) and adult indirect migrations(e and f). All transects proceed from the core of the otolith towards the edge. X-axes are unequal and represent the distance from the otolith core in microns; age 0 transects are complete but adult transect are abbreviated at the point of migration to saltwater. The left y-axes are unequal and denote otolith Sr:Ca concentration (umol/mol). The right y-axes are unequal and denote otolith Ba:Ca concentration (umol/mol).
54 CHAPTER THREE
Retrospective Determination of River Herring Daily Age at Emigration and Relationship to Subsequent Life History
INTRODUCTION
Events in the early life histories of fish can be essential to understanding population dynamics and demography. During the larval and juvenile stages fish cohorts typically suffer mortality at levels extensive enough to determine the resulting year-class strength. Influential events can even be rooted in circumstances predating the hatching of an individual. As an example, maternal fitness can have important ramifications for offspring and has been linked to early larval size, growth and survival (Berkeley et al.
2004; Einum and Fleming 1999; Heath et al. 1999). In bluefish (Pomatomus saltatrix), cohorts hatched in the spring maintain an advantage in size and survivorship over cohorts hatched in the summer and autumn and are typically disproportionately represented in adult year-classes (Callihan et al. 2008; Conover et al. 2003; Munch and Conover 2000;
Scharf et al. 2006). Likewise, dwarf surf perch (Micrometrus minimus) females that were members of early birthed cohorts were more successful during the first breeding season than females in late birthed cohorts (Schultz 1993).
There are two distinct types of variability in the timing of emigration in juvenile fish: seasonal and ontogenetic. Hatch or birth date is commonly used to measure the seasonal effects of timing on development and emigration (e.g. Conover et al. 2003;
Schultz 1993). Alternatively, age at emigration is used to measure the ontogentic development of fish leading to emigration (e.g. Gahagan et al. 2010; Limburg 1996;
Zydlewski and McCormick 1995). Both types may be important in examining juvenile
55 patterns of emigration and can be coupled (Gahagan et al. 2010; Iafrate and Oliveira
2008; Limburg 2001; Schultz et al. 2005).
This study examined the effects of age 0 migratory timing on the subsequent development of two anadromous alosines, alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis). Previous work on juvenile alewife demonstrated that age was connected to seasonal patterns of emigration; excluding an early cohort of older fast growing fish, the age and size of emigrants increased over the course of the emigration season (Gahagan et al. 2010). Age at emigration was also connected to condition, as fish that were older and emigrated later in the summer had less residual mass than fish that were younger and left earlier (Gahagan et al. 2010).
Driven by concerns about dwindling population levels (Davis and Schultz 2009;
Greene et al. 2009; NMFS 2007; Schmidt et al. 2003) research on juvenile river herring emigration, particularly alewife, has been increasing (Gahagan et al. 2010; Iafrate and
Oliveira 2008; Kosa and Mather 2001; Walsh et al. 2005; Yako et al. 2002). These studies complement earlier work that described emigration timing and emigrant charcteristics (Cooper 1961; Havey 1973; Kissil 1974; Loesch and Lund 1977).
Migration timing of age 0 river herring can be highly variable, occurring in New England from June until as late as December (Iafrate and Oliveira 2008; Kosa and Mather 2001;
Loesch 1965) and at ages as young as 31 days and as old as 157 days (Gahagan et al.
2010; Iafrate and Oliveira 2008; Yako et al. 2002). Over the course of the migration season differences in size at emigration, age at emigration, and condition have all been documented (Gahagan et al. 2010; Iafrate and Oliveira 2008; Yako et al. 2002).
Differences in emigrating age 0 and variability in nursery residence time suggest that
56 events in the juvenile life stage may influence the subsequent fitness of individual river herring and merit further investigation (Gahagan et al. 2010).
Given the previous findings specific to river herring and an extensive literature on the advantages of early hatch date and relative age there is an a priori expectation that individuals that emigrate at a younger age will likely carry these advantages forward to later events in life such as yearly growth, size at maturity, and age at maturity. The existence of anadromy in northern hemisphere fish is postulated to have developed upon increased opportunities for growth in marine habitats (Gross et al. 1988). Hence one would expect that by emigrating early individuals should increase their size and condition advantage over late emigrants. Alternatively, abundant food resources in the marine zone could be offset by increased mortality, effectively nullifying any advantage to early emigration. It is also possible that any consequences of emigration timing could be erased by the 3 – 5 years river herring spend in the ocean developing to maturity.
Otolith microchemistry represents a new and powerful tool to investigate the early life of fishes. Tracking movements of age 0 fish has been problematic using conventional techniques; many juvenile fish are too small or fragile to support the types of tags (i.e. telemetry techniques) that allow for monitoring of fish movements. The ability to discern transitions between waters of different salinity through Sr:Ca and Ba:Ca ratios within the otolith has been well documented and used to elucidate movement patterns of diadromous fishes (Elsdon and Gillanders 2005; Kennedy 2002; Limburg
1995; Limburg 1998a; Lochet et al. 2008; Secor et al. 1995). Ba and Sr are effective biogeochemical tracers because there are large differences in the concentration of these elements in freshwater and seawater and they typically form gradients associated with
57 salinity in estuarine habitats (Coffey et al. 1997; Ingram and Sloan 1992; Shaw et al.
1998; Stecherlii and Kogut 1999). Water Sr and Ba concentrations are reflected in the otoliths of fish (Bath et al. 2000; Walther and Thorrold 2006a). Combined with the time- keeping properties of the otolith, the microchemical record allows for retrospective tracking of fish across environments and estimation of when in their life these transitions occurred. Limburg (2001) clearly demonstrated the potential of applying otolith microchemistry to life history components in her study of an anadromous alosine, the
American shad (Alosa sapidissima).
The objective of this study was to determine if age at emigration had an effect on subsequent life history fitness correlates. We combined the unique temporal properties of the otolith with movement patterns derived from an individual’s otolith microchemistry record to retrospectively estimate age at emigration and examined correlations between age at emigration and that fish’s length at age 1and age and size when it returned to spawn as an adult. Otolith microchemistry has been used to track the movement of diadromous clupeids (Limburg 1995; Limburg 1998a) and more recently to estimate the age of life history transitions (Lochet et al. 2008); the application presented here is a novel approach to investigating the ramifications of emigration timing.
METHODS
River Herring Collection and Analysis
The fish used in this study were a subset of fish collected and analyzed in chapter
2. Adult alewife and blueback herring on their spawning runs were collected from March through June during the springs of 2008 and 2009 (Appendix 1). To obtain a
58 representative temporal sample of returning adults fish were collected from each site every 8-12 days for a total of 3 to 5 sampling dates per site. To ensure complete representation of size and age class variation within runs, fish were classified by 5-mm size increments during each sampling event and one to two fish per size class were retained for otolith extraction. To identify the Sr:Ca and Ba:Ca ratios that represented freshwater residency, age 0 fish were sampled from the same collection sites as adults during the summer and autumn of 2008 and 2009.
Multiple sampling gears were used to capture fish. Gear selection depended upon the habitat type of the sampling area and concentration of fish in that area. Adult and age
0 fish were collected with dip nets, cast nets, and backpack and boat electrofishers. The total length of all retained fish was recorded to the nearest mm and weight to the nearest
0.1 g. Sex was determined by expressing individual fish and gut cavity inspection for sperm or eggs. Species were identified by external coloration, basic morphology, and for those fish retained for otolith extraction, pigmentation of the peritoneal lining (Collette and Klein-MacPhee 2002; Walsh et al. 2005). Fifteen to 20 scales were removed from the left side of adult fish above the lateral line anterior to the dorsal fin (Davis and
Schultz 2009) and placed in scale envelopes after which the fish was euthanized via cold shock, sealed in individual bags and placed on ice. Fish were frozen whole until otoliths were removed several weeks subsequent to collection.
Hard Part Preparation and Analysis
Both sagittal otoliths were removed from each fish using nonmetallic forceps, thoroughly rinsed in reverse osmosis de-ionized (DI) water to remove any organic
59 materials and stored in capped polyethylene vials until otolith microchemistry preparation.
One otolith from each adult fish was chosen randomly and prepared for analysis.
The selected otolith was embedded in Epo-Fix epoxy (Struers, Inc.) and sectioned in the transverse plane using an ISOMET low-speed saw. Each otolith was cut twice, creating a section of otolith with the core at the center. Likewise, one otolith from each age 0 fish was randomly selected and prepared. Age 0 otoliths were placed in thermoplastic glue and ground in the frontal plane. All otoliths were ground evenly with multiple grades of silicon carbide (SiC) wet/dry sandpaper and polished with 3 µm lapping film to reveal growth increments and create a polished surface prior to ablation. Prepared otoliths were affixed to acid-washed glass slides using double-sided tape (3M), placed in polypropylene petri dishes and ultrasonically cleaned for 5 minutes in Ultrapure water
(Fisher Scientific). Samples were then dried in a Class 100 laminar flow hood. After drying the samples were sealed and placed in a container for transport to the Great Lakes
Institute for Environmental Research (GLIER) at the University of Windsor, Canada.
Adult otolith thin sections and juvenile whole otoliths were analyzed for 7Li,
25Mg, 39K, 43Ca, 44Ca, 55Mn, 57Fe, 60Ni, 62Ni, 63Cu, 65Cu, 66Zn, 67Zn, 86Sr, 88Sr,
118Sn, 120Sn, 138Ba, and 238U, using a Finnegan Thermo Elemental X7 inductively coupled mass spectrometer (ICPMS) coupled with a Quantronix Integra C® femtosecond
(fs) laser. Transects were ablated from the dorsal side of the otolith out to the ventral edge passing through the core (beam diameter = 24 µm, laser pulse rate = 100 Hz, laser energy level = 0.026 mJ/pulse, wavelength 785 nm, dwell time = 253 ms). A National
Institute of Standards and Technology (NIST) 610 standard was ablated every 5-17
60 samples to adjust for possible instrument drift. Each sample analysis was preceded by a gas blank measurement. Isotopic counts were converted to elemental concentrations
(µg/g) after correction for gas blank, matrix, and drift effects. Elemental concentrations were normalized to Ca, which was considered an internal pseudostandard (Bickford and
Hannigan 2005; Ludsin et al. 2006; Whitledge et al. 2007). All otolith microchemistry data are reported as molar element:Ca ratios (µmol/mol).
The Sr:Ca and Ba:Ca ratios of age 0 otolith were used to estimate thresholds that demarcated environmental transitions in individual fish. Since Sr:Ca ratios increase upon transition to saltwater and Ba:Ca ratios decrease the 95th percentile of Sr:Ca measurements and 5th percentile of Ba:Ca measurements were used to facilitate identification of the point of emigration (Lochet et al. 2008). Distance from the beginning of the ablation to the point of emigration was then derived using the bi-vector speeds of the laser and the time elapsed at point of emigration:
, where D is the distance (µm) at the point of emigration, t is the time (s) elapsed in the ablation at the point of emigration, X is the laser speed (µm-s) in the X-plane, and Y is the laser speed (µm-s) in the Y-plane.
After ablation cross-sectioned otoliths were examined using light microscopy to determine which otoliths retained adequate daily age information after preparation and ablation. Otoliths with intact daily age information were subsequently imaged at 500X
(Olympus QC-3 camera paired with an Olympus CX41 compound microscope, Image-
Pro Express). The magnification required to capture daily age increments necessitated that whole otolith montages be reconstructed from multiple images of each otolith.
61 During imaging landmarks on the otolith were sought to facilitate later merging of the images. Images were imported into Adobe Photoshop CS3 which was used to merge individual images into cohesive montage of the whole otolith. Each whole otolith montage was composed of 9 to 13 separate images (Figure 3.1).
To estimate daily age at emigration merged whole otolith montages were imported into a digital image analysis program (Image-Pro Express 5.1) and measured; the point at which the fish emigrated was then marked. Laser diameter was less than 5 daily increments wide for almost all growth periods. Daily growth increments were then enumerated from that point back to the core. At least two replicate counts of daily age were made and then averaged to arrive at a daily age estimate (Schultz 1990). In cases where the laser ablation partially destroyed part of core of an otolith the number of increments was estimated based upon prior experience reading age 0 anadromous river herring otoliths and added to the counted total. Daily age increments have not been validated for either species but have been validated in the closely related American shad
(Limburg 1994, Lochet et al. 2008).
Annual age and spawning marks were identified from scales. Whole otoliths and scales were considered for determination of annual age; scales had clearer annuli, allowed for more consistent orientation, and allowed us to increase the size of our sample as both otoliths from some fish had been altered in preparation for LA-ICPMS analysis.
Three to 6 non-regenerated scales from each fish were cleaned in distilled water and 70% ethanol, then dried and mounted between glass slides. Prepared scales were then imaged at 1.5X to 3X magnification (Olympus QC-3 camera paired with an Olympus SZ61 dissection microscope). The ageing protocol used followed that outlined in Davis and
62 Schultz (2009) and was based upon the clupeid aging protocols developed by Cating
(1953) and Marcy (1969). Annual age validation has not been performed for either species.
Data Analysis
To calculate lengths at age, annuli (Figure 3.2) were identified from the scale images and the distances from the core to the annuli were measured in a digital image analysis program (Image-Pro Express 5.1). Computationally, back calculated lengths were generated using the proportional Dahl-Lea method (Lea 1910):
,
Where Li is the length (mm) at age increment i, Si is the scale radius at age-increment i,
Sc is the scale radius at capture, and Lc is the total length of the fish (mm) at capture
(Figure 3.2). For virgin fish, the age at capture and length at capture were considered age at maturity and length at maturity. In cases where spawning checks were identified
(Figure 3.2) the age and back calculated length at the spawning check were used to determine age and length at maturity for that individual.
Separate analyses were conducted for each species of fish to safeguard against any physiological differences that might confound results. For each species the influence of sex on fitness correlates was evaluated via one-way analysis of variance (ANOVA).
Relationships between age at emigration, length at age 1, length at maturity, and age at maturity were assessed using Pearson correlation coefficients. Since length at maturity and age at maturity are often highly correlated and the effects of one might interfere with or obscure the other the two variables were considered independently and also combined into principal components (PROC PRINCOMP, SAS 9.2). Principal Component
63 Analysis (PCA) takes many variables that are likely correlated and combines them into new variables, or vectors, that explain as much of the variation in the data as possible. In this instance PCA was used to create two new variables from length at maturity and age at maturity that combined the effects of the fitness correlates. The normality of all variables was examined via the Shapiro-Wilkes statistic. Data that violated normality assumptions were log-transformed. All tests were assessed at the α = 0.05 level.
RESULTS
The fish examined in this study represented four year classes and a range of lengths; most fish were virgin spawners. After preparation for LA-ICPMS and ablation a total of 38 fish from the original collection retained daily growth increments visible enough to allow enumeration. Of these 38 individuals 15 had cores that were partially obstructed necessitating an adjustment in estimated age (alewife: mean adjustment = 5.00 days; SD = 7.07: blueback herring: mean adjustment = 4.58 days; SD = 4.98). The species were unevenly represented; there were 28 alewife between 2 and 5 years of age and 217 – 287 mm long and 12 blueback herring between 2 and 5 years of age and 226 –
269 mm long (Table 3.1; Appendix 3). The alewife sample consisted of 10 females and
16 males and there were 2 female and 10 male blueback herring (Table 3.1). Spawning checks were detected for 4 individuals; back calculated lengths at the spawning check and age at spawning check were substituted for the length at maturity and age at maturity of these fish.
Not all variables of interest were distributed normally. Alewife age at emigration and age at maturity violated normality assumptions; the former due to an outlier and the
64 latter from the predominance of age 2 and 3 fish. All analyses that assumed a normal distribution (i.e. one-way ANOVAs) and involved these variables were performed on natural log transformed data.
Both species demonstrated variable length at age 1. Back calculated lengths for alewife at age 1 ranged between 134.21mm – 237.20 mm and blueback herring ranged from 103.97 – 187.56 mm (Table 3.2; Appendix 4). Sex had no discernible effect on alewife or blueback lengths at age 1 (one-way ANOVAs: alewife: F = 0.28; df = 1, 24; P
= 0.6002; blueback herring: F = 0.05; df = 1, 10; P = 0.8210).
Alewife emigrated over a range of ages within that of published studies and typically matured at 3 years of age and 250mm long. Age at emigration ranged between
30 and 139 days. There was no difference in age at emigration due to sex of the individual (one-way ANOVA: F = 0.13; df = 1, 24; P = 0.7229). Age at emigration was unimodal with the greatest number of fish, both male and female, emigrating between 40 to 59 days of age (Fig. 3.3a). The distribution of age at emigration was positively skewed and no fish that emigrated between the ages of 100 and 120 days were collected. Length at maturity for alewife differed between the two sexes (one-way ANOVA: F = 5.37; df =
1, 24; P = 0.0293; Fig 3.3b). The distribution of male alewife was unimodal; most males were between 230 – 250 mm at maturity. Female lengths at maturity were equally represented by fish between 240 – 250 mm and 270 – 280 mm. Age at maturity was not significantly influenced by sex (one-way ANOVA: F = 1.87; df = 1, 24; P = 0.1846); alewife most commonly matured at 3 years of age (Fig 3.3c).
Sex did not influence blueback herring age at emigration, length at maturity, or age at maturity (one-way ANOVAs: age at emigration: F = 0.51; df = 1, 10; P = 0.4907;
65 length at maturity: F = 0.18; df = 1, 10; P = 0.6836; age at maturity: F = 0.02; df = 1, 10;
P = 0.9040). Emigration ages ranged between 37 – 136 days; the distribution of ages was dominated by fish that emigrated between 40 – 80 days or 100 – 140 days (Fig 3.3d).
Blueback herring length at maturity for both sexes was similar to male alewife, with the majority of fish maturing at lengths of 230 – 250 mm. The two female bluebacks were between 240 -250 mm while the majority of males were between 230 – 240 mm (Fig.
3.3e). The predominant age at maturity was 3 years old with a few age 2 fish and five fish older than 3 represented (Fig 3.3f)
Age at emigration was strongly related to length at age 1 in alewife but the relationship was weaker in blueback herring; fish that emigrated at greater ages were shorter at than end of their first year of life than fish that left at younger ages. Alewife age at emigration and length at age 1 were negatively correlated (r = -0.6559; P = 0.0003;
Fig 3.4a). The evident outlier in Figure 3.4a (male alewife, age at emigration =139) influenced the correlation between age at emigration and length at age 1; when this observation was removed the correlation remained negative but the p-value increased (r =
-0.3656; P = 0.0723). Blueback age at emigration and length at age 1 were negatively correlated; the relationship was not significant at the α = 0.05 level but a weak relationship was evident (r = -0.5004; P = 0.0975; Fig. 3.4c).
Although age at maturity and length at maturity did not initially appear to be related to age at emigration, there was a strong positive relationship between length at maturity and age at maturity observed in both species. Alewife age at emigration was not correlated to age at maturity or length at maturity, although a weak relationship was observed for length at maturity (age at maturity: r = 0.14913; P = 0.4672; length at
66 maturity: r = -0.37929; P = 0.056). Neither age nor length at maturity were correlated with age at emigration in blueback herring (age at maturity: r = 0.28149; P = 0.3754; length at maturity: r = -0.23465; P = 0.4629). Alewife length at maturity increased as age at maturity increased, although there was variation in size at maturity within age groups (r = 0.6179; P = 0.0008; Fig. 3.4b). The relationship between length at maturity and age at maturity for blueback herring was positive (r = 0.7340; P = 0.0066); the size of fish at maturity increased along with age at maturity but with noticeable overlap between groups (Fig. 3.4d).
Early age at emigration was correlated with larger size at age 1 (Figs. 3.4a and c) and larger size at maturity through PC2 (Figs. 3.5a and b). The combination of age at maturity and length at maturity into a principal component, when related to age at emigration, suggested that alewife and blueback herring that emigrated at younger age matured at younger ages and at greater lengths at age than their counterparts that emigrated at older ages. The principal component analysis created 2 vectors. Age at maturity and length at maturity both had positive loadings on the first vector (PC1), which explained 81% of the variance in the alewife data and 87% in blueback herring.
The second principal component (PC2) explained 19% of the variability in the alewife data and 13% in the blueback herring; age at maturity had a positive loading on this vector and length at maturity had a negative loading. Age at emigration was not correlated with PC1 (alewife: r = -0.12795; P = 0.5333; blueback herring: r = 0.02515; P
= 0.9832). The principal component combining greater age at maturity and smaller length at maturity (PC2) was significantly positively correlated to age at emigration in alewife and blueback herring (alewife: r = 0.60446; P = 0.0011; blueback herring: r =
67 0.70769; P = 0.0100), indicating that fish that emigrated at a younger age matured at a younger age with greater size (Figs. 3.6a and b). Additionally, length at age 1 was predictive of fitness correlates; alewife and blueback herring that were larger at age 1 returned to spawn at a younger age and larger size at that age than fish that were relatively smaller at age 1. A significant negative relationship existed between length at age 1 and PC2 for both species of river herring (alewife: r =- 077013; P < 0.0001; blueback herring: r = -0.6762; P = 0.0158). The negative correlation, opposite from age at emigration, confirms the earlier results as larger size at age 1 was associated with emigration at a younger age (Figs 3.6a and b).
DISCUSSION
The age at which river herring emigrated to saltwater as juveniles was strongly tied to measures of individual fitness later in life. Fish that emigrated to marine environments at younger ages matured at a younger age and greater size at that age than fish that spent prolonged time in freshwater nurseries. This relationship also applied to length at age 1, suggesting that the superior size and condition that can accompany emigration at earlier age (Gahagan et al. 2010) persisted during juvenile development in marine environments. These findings confirm previous observations about the importance of early life history formed from life history theory and previous research
(Limburg 2001). Results presented here are the first to directly link age at emigration to correlates of fitness in diadromous clupeids. The potential importance of development in nursery areas suggests that the monitoring and management of this crucial life stage may facilitate species recovery.
68 Emigration at an early age was linked to greater sizes in the first year of life as well as at maturity. Emigration to marine environments theoretically occurs because of higher productivity and more opportunities for growth (Gross et al. 1988) and the benefits of emigration can be observed in young emigrants. Greater size over the course of life should confer several advantages. Larger individuals should be more developed and able to swim faster and, by virtue of greater energy reserves, sustain swimming activity longer than smaller individuals. This would confer competitive advantages in both predator avoidance and prey capture. Larger fish should also have larger gape sizes allowing them to pursue and consume larger, more energetically rewarding prey items, reduce handling time of prey, and consume prey at higher rates. Larger size at maturity also produces direct fitness advantages. Generally larger females are expected to produce more eggs than smaller females (Murua et al. 2003). In both alewife and blueback herring, length of females has been linked to increased fecundity, although the relationship is variable among populations (Jessop 1993; Kissil 1969; Loesch and Lund 1977; E. Schultz,
University of Connecticut, unpublished data). Becoming sexually mature at an earlier age should also be advantageous for iteroparous fish as it would create more potential reproduction events over the lifetime of the fish and would also result in multiple generations of progeny at an earlier date. Energetic thresholds to migration have been identified in alewife; prior work at one of the sites included in this research indicated that emigrants were not a random subset of the population within the nursery (Gahagan et al.
2010). Specifically, emigrants had improved condition and were larger at age than non- migrants. Waves of emigration from nursery habitats can also be related to the abundance of prey items for juvenile river herring, typically large zooplankton (Post et al.
69 2008; Vigerstad and Cobb 1978). Once food resources in the natal nursery are exhausted individuals that are physiologically prepared to emigrate do so in large numbers
(Gahagan et al. 2010; Post et al. 2008).
Late age emigrants, especially those transitioning at ages greater than 100 days, may have been entrapped by low flows between nursery areas and marine habitats. Fish that are denied egress in nursery areas can suffer energetic debts and emerge in poorer condition (Gahagan et al. 2010). Waterways connecting nursery and estuarine or marine habitats can be affected by both natural and anthropogenic processes. As coastal populations and development continue to expand, human demands for water (Nadim et al. 2007) in conjunction with global warming phenomena (Hayhoe et al. 2008; Moore et al. 1997; Nelson et al. 2009) could lead to periods of increasing freshwater entrapment for age 0 river herring. Given the previously observed immediate negative impacts and the suggested possibility that those impacts are carried throughout an individual’s life the necessity of ensuring adequate in-stream flows for migrating fish becomes a conservation priority.
The variability observed in life history patterns raises an important question about the necessity of having such variance. The results suggest that fish that migrate at a younger age have higher fitness and could be seen as the more important life history component. Thus late migrants could serve minimal purpose and, as it is sometimes referred to, simply be ‘making the best of a bad job,’ meaning they are simply surviving to reproduce but contributing little to the evolution of a species or stability and population persistence. Alternatively, it is quite possible that the variability observed, especially as it is linked in some fashion to hatch date, is a form of temporal cohort splitting (Secor
70 2007). In this scenario fish that emigrate at greater ages, likely hatched as part of a later cohort (Gahagan et al. 2010), would provide essential life history variability and population resilience in years where abnormal conditions could otherwise lead to year class failures (Secor 2007; Secor et al. 2009). Hence, fish that emigrate at later ages may be of conservation importance over the long term.
The findings presented here must be considered carefully. The results are based on a limited sample size, especially for blueback herring. It is promising that correlations were evident from a small sample that likely did not capture the full variation present in the populations but it is possible that as sample size increased the patterns might change.
Our sampling was also limited temporally; alewife and blueback herring examined came from 4 year-classes (2004-2007); it is unlikely that our results capture the species specific response to patterns in ocean circulation and weather that operate on time scales that are often decadal or longer. There has been little research, historic or recent (but see Milstein
1981), on the distribution of river herring in marine waters and no estimates of mortality during the period between emigration and spawning. It is possible that variable survival and differential mortality during this period may also relate to population consequences with equal or greater magnitude than age at emigration. I acknowledge that we did not have available estimates of the time lag from when a fish moved from freshwater to the marine environment until the microchemistry of the otolith would reflect the change, which would influence the estimates of age at emigration. However, the lag should be relatively constant across individuals within the same species and the estimates of age at emigration conformed well to those reported in studies that collected actively emigrating age 0 fish (Gahagan et al. 2010; Iafrate and Oliveira 2008; Yako et al. 2002).
71 This study provides a glimpse at the possible information that can be gained utilizing these methods. In the future several refinements could be made to increase efficacy and provide clearer results. Adult otoliths were prepared in the transverse plane which facilitated mounting and allowed for reliable access to the portion of the otolith corresponding to time spent in natal areas. However, this approach infrequently preserved all the daily rings because the ablation transect obscured some of the rings particularly near the otolith core. This artifact of the preparation and ablation methods ultimately reduced sample sizes. Future studies should experiment with alternate preparations and ablation analyses (e.g. frontal and sagittal planes; ablate ‘spots’ rather than transects) that might improve results. Also this study used age at emigration without knowledge of hatch date. Gahagan et al. (2010) subsampled and estimated age at emigration of age 0 alewife and were able to assign hatch date estimates by counting back from date of collection. In this study I sampled returning adults and it was impossible to count back to a hatch date estimate. It is likely that some of the relationships examined were weakened or obscured by this reliance. If data on seasonal growth rates was created from otolith daily growth increments for a number of river herring populations it could be possible to assign adult fish to temporal cohorts based upon otolith growth patterns during freshwater residency.
This study demonstrated that otolith microchemistry could be used to conduct retrospective analyses of individual-level attributes. The uncovered relationships between age at emigration, length at age 1, length at maturity, and age at maturity have not been explored previously and alternate methods to conduct such work are not apparent. Studies with this focus have been rare (Limburg 2001; Lochet et al. 2008) but
72 the obvious utility of the technique and the increasing awareness of its capabilities will hopefully lead to more investigations of this type.
73
Table 3.1 Summary table of species , sex, and age in years for alewife and blueback herring used in the study. Species Sex Age Number Observed Alewife Female 2 2 3 4 4 3 5 1 Male 2 6 3 5 4 4 5 1 Blueback Herring Female 4 1 5 1 Male 2 2 3 4 4 2 5 2
74 Table 3.2 Mean lengths at age for alewife and blueback herring based upon recorded lengths at capture and back calculations. Back calculated lengths were generated using the proportional Dahl-Lea method on measurements from scales. Species Age Increment N Mean SE SD Alewife 1 26 196.33 4.05 20.67 2 26 229.37 3.52 17.96 3 18 248.66 4.26 18.07 4 9 262.78 6.46 19.39 5 2 263.50 12.50 17.68 Blueback 1 12 157.80 9.20 31.88 2 12 208.95 6.67 23.12 3 10 234.17 4.01 12.69 4 6 250.49 3.87 9.48 5 3 262.67 3.28 5.69
75
Figure 3.1 Demonstration of the techniques used to combine otolith microchemistry data and the ability to count daily growth increments to estimate the age at emigration for juvenile river herring (PR913). The red circles mark daily growth increments (n = 58), the straight red line marks the path of laser ablation to the point the fish emigrated. On the graph the solid red line is otolith Sr:Ca (µmol/mol) and the dashed blue line is Ba:Ca (µmol/mol).
76 2
Annuli
Spawning check
FWZ
Figure 3.2 Scale from an alewife with, freshwater zone (FWZ), annuli, and spawning check marked. Spawning checks result when a fish enters freshwater to spawn and scale erosion occurs. Spawning checks are counted as an annulus.
77 a) d)
b) e)
c) f)
Figure 3.3 Bar graphs depicting the frequency distributions for age at emigration, total length (mm) at maturity, and age at maturity for alewife (Figs. a - c) and blueback herring (Figs. d - f). The bars are stacked by sex with males depicted in light blue and females in dark blue. The Y-axes represent the number of individuals observed and are unequal. The X-axes represent age at emigration (Figs. a and d), total length (mm) at maturity (Figs. b and e), and age at maturity (Figs. c and f).
78 a) c)
b) d)
Figure 3.4 Scatterplots of length at age 1 (mm) against age at emigration (days) and length at maturity (mm) against age at maturity (years) for alewife (Figs. a and b) and blueback herring (Figs. c and d). Females are represented by open circles and males by closed triangles.
79
a)
b)
Figure 3.5 Scatterplots of Principal Component 2 (increased age at maturity – decreased size at maturity) against age at emigration (days) for alewife (a) and blueback herring (b). Females are represented by open circles and males by closed triangles.
80 a)
b)
Figure 3.6 Scatterplots of Principal Component 2 (increased age at maturity – decreased size at maturity) against length at age 1 (mm) for alewife (a) and blueback herring (b). Females are represented by open circles and males by closed triangles.
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90 Thorrold, S. R., and S. Shuttleworth. 2000. In situ analysis of trace elements and isotope ratios in fish otoliths using laser ablation sector field inductively coupled plasma mass spectrometry. Canadian Journal of Fisheries & Aquatic Sciences 57:11. Thresher, R. E. 1999. Elemental composition of otoliths as a stock delineator in fishes. Fisheries Research 43(1-3):165-204. Thunberg, B. E. 1971. Olfaction in parent stream selection by the alewife (Alosa pseudoharengus). Animal Behavior 19(2):217-225. Tilman, D., Clarence L. Lehman, and Charles E. Bristow. 1998. Diversity-Stability Relationships: Statistical Inevitability or Ecological Consequence? The American Naturalist 151(3):277-282. Tomas, J., S. Augagneur, and E. Rochard. 2005a. Discrimination of the natal origin of young-of-the-year Allis shad (Alosa alosa) in the Garonne-Dordogne basin (south-west France) using otolith chemistry. Ecology of Freshwater Fish 14(2):6. Tomas, J., S. Augagneur, and E. Rochard. 2005b. Discrimination of the natal origin of young-of-the-year Allis shad (Alosa alosa) in the Garonne-Dordogne basin (south-west France) using otolith chemistry. Ecology of Freshwater Fish 14(2):185-190. Uphoff, J. H. 2003. Predator-prey analysis of striped bass and Atlantic menhaden in upper Chesapeake Bay. Fisheries Management and Ecology 10(5):313-322. Veinott, G., and R. Porter. 2005. Using otolith microchemistry to distinguish Atlantic salmon (Salmo salar) parr from different natal streams. Fisheries Research 71(3):349-355. Vigerstad, T., and J. Cobb. 1978. Effects of predation by sea-run juvenile alewife (Alosa pseudoharengus) on the zooplankton community at Hamilton Reservoir, Rhode Island. Estuaries and Coasts 1(1):36-45. Volk, E. C., A. Blakley, S. L. Schroder, and S. M. Kuehner. 2000. Otolith chemistry reflects migratory characteristics of Pacific salmonids:: Using otolith core chemistry to distinguish maternal associations with sea and freshwaters. Fisheries Research 46(1-3):251-266. Walsh, H. J., L. R. Settle, and D. S. Peters. 2005. Early Life History of Blueback Herring and Alewife in the Lower Roanoke River, North Carolina. Transactions of the American Fisheries Society 134(4):910-926. Walter, J. F., A. S. Overton, K. H. Ferry, and M. E. Mather. 2003. Atlantic coast feeding habits of striped bass: a synthesis supporting a coast-wide understanding of trophic biology. Fisheries Management and Ecology [Fish. Manage. Ecol.]. 10(5):349-360. Walters, A. W., R. T. Barnes, and D. M. Post. 2009. Anadromous alewives (Alosa pseudoharengus) contribute marine-derived nutrients to coastal stream food webs. Canadian Journal of Fisheries and Aquatic Sciences 66(3):439-448. Walther, B. D., and S. R. Thorrold. 2006a. Water, not food, contributes the majority of strontium and barium deposited in the otoliths of a marine fish. Marine Ecology Progress Series 311:125-130. Walther, B. D., and S. R. Thorrold. 2006b. Water, not food, contributes the majority of strontium and barium deposited in the otoliths of a marine fish. Marine Ecology Progress Series 311:6.
91 Walther, B. D., and S. R. Thorrold. 2008a. Continental-scale variation in otolith geochemistry of juvenile American shad (Alosa sapidissima). Canadian Journal of Fisheries and Aquatic Sciences 65:2623-2635. Walther, B. D., and S. R. Thorrold. 2008b. Geochemical Signatures in Otoliths Record Natal Origins of American Shad. Transactions of the American Fisheries Society 137:57-69. Wheeler, A. P., and C. S. Sikes. 1984. Regulation of Carbonate Calcification by Organic Matrix. American Zoologist 24(4):933-944. White, J. W., and B. I. Ruttenberg. 2007. Discriminant function analysis in marine ecology: some oversights and their solutions. Marine Ecology Progress Series 329:301-305. Whitledge, G. W., B. M. Johnson, P. J. Martinez, and A. M. Martinez. 2007. Sources of Nonnative Centrarchids in the Upper Colorado River Revealed by Stable Isotope and Microchemical Analyses of Otoliths. Transactions of the American Fisheries Society 136(5):1263-1275. Williams, B. K., and K. Titus. 1988. Assessment of Sampling Stability in Ecological Applications of Discriminant Analysis. Ecology 69(4):1275-1285. Yako, L. A., M. E. Mather, and F. Juanes. 2000. Assessing the contribution of anadromous herring to largemouth bass growth. Transactions of the American Fisheries Society 129(1):77-88. Yako, L. A., M. E. Mather, and F. Juanes. 2002. Mechanisms for migration of anadromous herring: An ecological basis for effective conservation. Ecological Applications Ecological Applications. 12(2):521-534. Zeigler, J., and G. Whitledge. 2010. Assessment of otolith chemistry for identifying source environment of fishes in the lower Illinois River, Illinois. Hydrobiologia 638(1):109-119. Zimmerman, C. E., and G. H. Reeves. 2002. Identification of Steelhead and Resident Rainbow Trout Progeny in the Deschutes River, Oregon, Revealed with Otolith Microchemistry. Transactions of the American Fisheries Society 131(5):986-993. Zimmerman,,C. E. 2005. Relationship of otolith strontium-to-calcium ratios and salinity: experimental validation for juvenile salmonids. Canadian Journal of Fisheries and Aquatic Sciences 62:88-97. Zydlewski, J., and S. D. McCormick. 1995. The Ontogeny of salinity tolerance in the American shad, Alosa sapidissima. Canadian Journal of Fisheries and Aquatic Sciences 54:182-189.
92 APPENDIX A
93
Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) BB801 BB 4/3/2008 M ALE 246 147 BB802 BB 4/3/2008 M ALE 256 150 BB803 BB 4/3/2008 F ALE 256 162 BB804 BB 4/3/2008 F ALE 242 232 BB805 BB 4/3/2008 F ALE 273 188 BB806 BB 4/3/2008 M ALE 233 112 BB807 BB 4/3/2008 F ALE 257 168 BB808 BB 4/3/2008 M ALE 253 164 BB809 BB 4/3/2008 F ALE 283 210 BB810 BB 4/3/2008 M ALE 262 168 BB811 BB 4/21/2008 F ALE 274 176 BB812 BB 4/21/2008 F ALE 277 210 BB813 BB 4/21/2008 F ALE 277 208 BB814 BB 4/21/2008 F ALE 258 162 BB815 BB 4/21/2008 F ALE 262 154 BB816 BB 4/21/2008 F ALE 271 176 BB817 BB 4/21/2008 M ALE 258 146 BB818 BB 4/21/2008 F ALE 249 150 BB819 BB 4/21/2008 M ALE 266 164 BB820 BB 4/21/2008 F ALE 279 190 BB821 BB 4/21/2008 F ALE 258 162 BB822 BB 4/21/2008 M ALE 257 154 BB823 BB 4/21/2008 F ALE 262 168 BB824 BB 4/21/2008 F ALE 262 168 BB825 BB 4/21/2008 M ALE 239 138 BB826 BB 4/21/2008 M ALE 260 158 BB827 BB 4/21/2008 M ALE 251 150 BB828 BB 4/21/2008 F ALE 271 168 BB829 BB 4/21/2008 F ALE 270 172 BB830 BB 4/21/2008 F ALE 251 158 BB901 BB 4/1/2009 M ALE 262 154 BB902 BB 4/1/2009 M ALE 274 200 BB903 BB 4/1/2009 M ALE 264 174 BB904 BB 4/1/2009 M ALE 229 98 BB905 BB 4/1/2009 F ALE 291 217 BB906 BB 4/1/2009 M ALE 267 182 BB907 BB 4/1/2009 M ALE 237 107 BB908 BB 4/1/2009 F ALE 282 204 BB909 BB 4/1/2009 F ALE 259 148 BB910 BB 4/1/2009 M ALE 253 130 BB911 BB 4/1/2009 F ALE 249 126 BB912 BB 4/1/2009 F ALE 276 198 BB916 BB 4/8/2009 M ALE 263 158 BB917 BB 4/8/2009 F ALE 267 172 BB918 BB 4/8/2009 F ALE 279 210 BB919 BB 4/8/2009 M ALE 249 138 BB920 BB 4/8/2009 M ALE 252 130 BB921 BB 4/8/2009 M ALE 250 120 BB922 BB 4/8/2009 F ALE 272 180
94 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) BB923 BB 4/8/2009 F ALE 256 154 BB924 BB 4/8/2009 M ALE 253 140 BB925 BB 4/8/2009 M ALE 256 154 BB926 BB 4/8/2009 F ALE 247 122 BB927 BB 4/8/2009 M ALE 237 110 BB928 BB 4/8/2009 F ALE 284 204 BB929 BB 4/8/2009 M ALE 236 116 BB930 BB 4/8/2009 M ALE 268 160 BB931 BB 4/8/2009 M ALE 242 124 BB932 BB 4/20/2009 M ALE 262 154 BB933 BB 4/20/2009 M ALE 252 144 BB934 BB 4/20/2009 M ALE 277 170 BB935 BB 4/20/2009 F ALE 258 152 BB936 BB 4/20/2009 F ALE 269 162 BB937 BB 4/20/2009 M ALE 242 126 BB938 BB 4/20/2009 F ALE 270 174 BB939 BB 4/20/2009 F ALE 289 238 BB940 BB 4/20/2009 M ALE 234 108 BB941 BB 4/20/2009 F ALE 283 224 BB942 BB 4/20/2009 F ALE 230 104 BB943 BB 4/20/2009 F ALE 231 110 BB944 BB 4/20/2009 F ALE 253 152 BB945 BB 4/20/2009 F ALE 249 154 BB946 BB 4/20/2009 M ALE 247 138 BB947 BB 4/20/2009 M ALE 238 NR BB948 BB 4/27/2009 F ALE 229 104 BB949 BB 4/27/2009 M ALE 247 146 BB950 BB 4/27/2009 M ALE 259 144 BB951 BB 4/27/2009 M ALE 262 168 BB952 BB 4/27/2009 F ALE 254 138 BB953 BB 4/27/2009 M ALE 238 116 BB954 BB 4/27/2009 M ALE 235 106 BB955 BB 4/27/2009 M ALE 232 106 EM801 EM 4/10/2008 F ALE 298 288 EM802 EM 4/10/2008 M ALE 277 190 EM803 EM 4/10/2008 F ALE 312 310 EM804 EM 4/10/2008 M ALE 260 158 EM805 EM 4/10/2008 M ALE 274 176 EM806 EM 4/10/2008 M ALE 282 214 EM807 EM 4/10/2008 M ALE 259 164 EM808 EM 4/10/2008 M ALE 267 164 EM809 EM 4/10/2008 M ALE 252 152 EM810 EM 4/10/2008 M ALE 295 236 EM811 EM 4/10/2008 M ALE 300 236 EM812 EM 4/10/2008 M ALE 290 200 EM813 EM 4/10/2008 F ALE 285 224 EM814 EM 4/10/2008 M ALE 274 172 EM815 EM 4/10/2008 M ALE 281 204 EM838 EM 4/21/2008 M ALE 250 126 EM839 EM 4/21/2008 M ALE 277 174
95 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) EM840 EM 4/21/2008 M ALE 309 244 EM841 EM 4/21/2008 M ALE 252 146 EM842 EM 4/21/2008 M ALE 262 166 EM843 EM 4/21/2008 M ALE 251 134 EM844 EM 4/21/2008 M ALE 274 190 EM845 EM 4/21/2008 M ALE 238 132 EM846 EM 4/21/2008 M ALE 276 170 EM847 EM 4/21/2008 M ALE 277 190 EM848 EM 4/21/2008 M ALE 252 152 EM849 EM 4/21/2008 M ALE 235 130 EM850 EM 4/21/2008 M ALE 282 216 EM851 EM 4/21/2008 M ALE 247 144 EM852 EM 4/21/2008 M ALE 266 170 EM853 EM 4/21/2008 M ALE 275 170 EM854 EM 4/21/2008 M ALE 278 186 EM855 EM 4/21/2008 M ALE 256 158 EM856 EM 4/21/2008 M ALE 267 174 EM857 EM 5/6/2008 F BBH 245 140 EM858 EM 5/6/2008 M BBH 275 170 EM859 EM 5/6/2008 F BBH 277 210 EM860 EM 5/6/2008 F BBH 254 156 EM861 EM 5/6/2008 M BBH 257 146 EM862 EM 5/6/2008 M BBH 244 124 EM863 EM 5/6/2008 M BBH 228 118 EM864 EM 5/6/2008 M BBH 254 148 EM865 EM 5/6/2008 F BBH 247 108 EM866 EM 5/6/2008 M BBH 272 152 EM867 EM 5/6/2008 M BBH 236 116 EM868 EM 5/6/2008 M BBH 263 166 EM869 EM 5/6/2008 M BBH 247 138 EM870 EM 5/6/2008 M BBH 244 108 EM871 EM 5/8/2008 M BBH 234 108 EM872 EM 5/8/2008 M BBH 239 124 EM873 EM 5/8/2008 M BBH 232 110 EM874 EM 5/8/2008 M BBH 242 120 EM875 EM 5/8/2008 M BBH 226 108 EM876 EM 5/8/2008 M BBH 235 120 EM877 EM 5/8/2008 M BBH 240 132 EM878 EM 5/8/2008 M BBH 250 132 EM879 EM 5/8/2008 M BBH 233 112 EM880 EM 5/8/2008 M BBH 43 132 EM881 EM 5/8/2008 M BBH 218 100 EM882 EM 5/8/2008 M BBH 249 140 EM883 EM 5/8/2008 M BBH 217 96 EM884 EM 5/8/2008 M BBH 239 118 EM885 EM 5/8/2008 M BBH 247 142 EM886 EM 5/8/2008 M BBH 228 100 EM887 EM 5/8/2008 M BBH 254 152 EM888 EM 5/8/2008 M BBH 245 124 EM901 EM 4/20/2009 F ALE 301 296
96 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) EM902 EM 4/20/2009 M ALE 232 106 EM903 EM 4/20/2009 F ALE 258 198 EM904 EM 4/20/2009 M ALE 236 108 EM905 EM 4/20/2009 M ALE 277 180 EM906 EM 4/20/2009 M ALE 251 140 EM907 EM 4/20/2009 M ALE 246 130 EM908 EM 4/20/2009 M ALE 240 184 EM909 EM 4/20/2009 F ALE 266 174 EM910 EM 4/20/2009 M ALE 295 220 EM911 EM 4/20/2009 M ALE 285 284 EM912 EM 4/20/2009 M ALE 226 96 EM913 EM 4/20/2009 M ALE 273 154 EM914 EM 4/20/2009 M ALE 245 120 EM915 EM 4/27/2009 M ALE 243 120 EM916 EM 4/27/2009 M ALE 236 114 EM917 EM 4/27/2009 F ALE 270 202 EM918 EM 4/27/2009 F ALE 250 154 EM919 EM 4/27/2009 M ALE 232 104 EM920 EM 4/27/2009 M ALE 244 126 EM921 EM 4/27/2009 M ALE 240 114 EM922 EM 4/27/2009 M ALE 232 94 EM923 EM 4/27/2009 M ALE 245 134 EM924 EM 4/27/2009 M ALE 267 144 EM925 EM 4/27/2009 M ALE 273 154 EM926 EM 4/27/2009 M ALE 262 136 EM927 EM 4/27/2009 M ALE 229 98 EM928 EM 4/27/2009 M ALE 288 176 EM929 EM 4/27/2009 M ALE 255 132 EM930 EM 5/10/2009 M BBH 247 114 EM931 EM 5/10/2009 M BBH 252 122 EM932 EM 5/11/2009 M BBH 251 142 EM933 EM 5/11/2009 F BBH 267 154 EM934 EM 5/11/2009 M BBH 253 134 EM935 EM 5/11/2009 M BBH 253 128 EM936 EM 5/11/2009 F BBH 250 166 EM937 EM 5/11/2009 M BBH 262 142 EM938 EM 5/11/2009 M BBH 241 114 EM939 EM 5/11/2009 M BBH 246 122 EM940 EM 5/11/2009 M ALE 236 104 EM941 EM 5/11/2009 F BBH 263 160 EM942 EM 5/11/2009 F BBH 259 120 EM943 EM 5/11/2009 M BBH 237 114 EM944 EM 5/11/2009 M BBH 247 104 EM945 EM 5/11/2009 M BBH 239 128 EM946 EM 5/11/2009 M BBH 236 108 FR801 FR 5/30/2008 M BBH 260 126 FR802 FR 5/30/2008 M BBH 257 130 FR803 FR 5/30/2008 F BBH 283 168 FR804 FR 5/30/2008 M BBH 260 150 FR805 FR 5/30/2008 F BBH 256 124
97 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) FR806 FR 5/30/2008 M BBH 242 122 FR807 FR 5/30/2008 F BBH 279 180 FR808 FR 5/30/2008 M BBH 238 110 FR809 FR 5/30/2008 M BBH 251 128 FR810 FR 5/30/2008 M BBH 252 128 FR811 FR 5/30/2008 M BBH 249 120 FR812 FR 6/2/2008 M BBH 257 138 FR813 FR 6/2/2008 F BBH 272 160 FR814 FR 6/2/2008 M BBH 254 124 FR901 FR 4/30/2009 M BBH 280 192 FR902 FR 4/30/2009 F BBH 247 132 FR903 FR 4/30/2009 F BBH 269 164 FR904 FR 4/30/2009 M BBH 282 184 FR905 FR 4/30/2009 F BBH 288 212 FR906 FR 4/30/2009 M BBH 274 166 FR907 FR 4/30/2009 F BBH 278 182 FR908 FR 4/30/2009 F BBH 291 218 FR909 FR 4/30/2009 F BBH 298 222 FR910 FR 4/30/2009 M BBH 264 158 FR911 FR 4/30/2009 M BBH 254 150 FR912 FR 4/30/2009 M ALE 268 162 FR913 FR 4/30/2009 M BBH 244 124 FR914 FR 4/30/2009 M ALE 286 186 FR915 FR 4/30/2009 F BBH 302 236 FR916 FR 4/30/2009 M BBH 256 152 FR917 FR 4/30/2009 M BBH 238 128 FR918 FR 5/6/2009 F BBH 264 184 FR919 FR 5/6/2009 M BBH 259 150 FR920 FR 5/6/2009 F BBH 295 222 FR921 FR 5/6/2009 F BBH 254 134 FR922 FR 5/6/2009 F BBH 279 202 FR923 FR 5/6/2009 F BBH 272 190 FR924 FR 5/6/2009 F BBH 269 176 FR925 FR 5/6/2009 M BBH 284 180 FR926 FR 5/6/2009 M BBH 242 124 FR927 FR 5/6/2009 F BBH 288 206 FR928 FR 5/6/2009 M BBH 238 116 FR929 FR 5/6/2009 M BBH 223 100 FR930 FR 5/6/2009 M BBH 264 168 FR931 FR 5/13/2009 M BBH 239 118 FR932 FR 5/13/2009 M BBH 250 138 FR933 FR 5/13/2009 M BBH 244 120 FR934 FR 5/13/2009 M BBH 259 144 FR935 FR 5/13/2009 F BBH 287 212 FR936 FR 5/13/2009 F BBH 276 16 FR937 FR 5/13/2009 F BBH 265 214 FR938 FR 5/13/2009 M BBH 248 130 FR939 FR 5/13/2009 M BBH 233 112 FR940 FR 5/13/2009 M BBH 261 146 FR941 FR 5/13/2009 F BBH 280 184
98 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) GR901 SH 4/22/2009 F ALE 282 204 GR902 SH 4/22/2009 M ALE 253 138 GR903 SH 4/22/2009 M ALE 263 168 GR904 SH 4/22/2009 F ALE 277 196 GR905 SH 4/22/2009 M ALE 256 164 GR906 SH 4/22/2009 M ALE 232 120 GR907 SH 4/22/2009 M ALE 267 162 GR908 SH 4/22/2009 M ALE 264 164 GR909 SH 4/22/2009 F ALE 245 152 GR910 SH 4/22/2009 F ALE 255 148 GR911 SH 4/22/2009 F ALE 270 184 GR912 SH 4/22/2009 M ALE 238 118 GR913 SH 4/22/2009 M ALE 274 170 GR914 SH 4/22/2009 F ALE 300 238 GR915 SH 4/27/2009 F ALE 285 226 GR916 SH 4/27/2009 M ALE 270 148 GR917 SH 4/27/2009 F ALE 298 238 GR918 SH 4/27/2009 F ALE 278 180 GR919 SH 4/27/2009 F ALE 273 192 GR920 SH 4/27/2009 F ALE 272 174 GR921 SH 4/27/2009 F ALE 242 130 GR922 SH 4/27/2009 M ALE 255 142 GR923 SH 4/27/2009 F ALE 268 136 GR924 SH 4/27/2009 M ALE 244 130 GR925 SH 4/27/2009 F ALE 296 274 GR926 SH 4/27/2009 M ALE 256 144 GR927 SH 4/27/2009 F ALE 274 190 GR928 SH 4/27/2009 F ALE 271 174 GR929 SH 4/27/2009 M ALE 235 106 GR930 SH 4/27/2009 M BBH 267 148 GR931 SH 4/27/2009 M ALE 250 150 GR932 SH 4/27/2009 F ALE 244 134 GR933 SH 5/11/2009 F BBH 251 134 GR934 SH 5/11/2009 M ALE 251 120 GR935 SH 5/11/2009 M BBH 239 112 GR936 SH 5/11/2009 F ALE 240 124 GR937 SH 5/11/2009 M ALE 289 186 HR001 HR 4/24/2008 M ALE 247 128 HR002 HR 4/24/2008 M ALE 228 116 HR003 HR 4/24/2008 M ALE 245 134 HR004 HR 4/24/2008 M ALE 247 148 HR005 HR 4/24/2008 M ALE 243 116 HR006 HR 4/24/2008 M ALE 232 118 HR007 HR 4/24/2008 M ALE 243 132 HR008 HR 4/24/2008 M ALE 247 142 HR009 HR 4/24/2008 M ALE 259 170 HR010 HR 4/24/2008 F ALE 264 176 HR011 HR 4/24/2008 M ALE 248 130 HR012 HR 4/24/2008 M ALE 249 130 HR013 HR 4/24/2008 M ALE 247 134
99 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) HR014 HR 4/24/2008 M ALE 241 110 HR015 HR 4/24/2008 M ALE 234 118 HR016 HR 4/24/2008 M ALE 256 158 HR017 HR 4/24/2008 M ALE 246 124 HR018 HR 4/24/2008 M ALE 257 164 HR019 HR 4/24/2008 M ALE 248 114 HR020 HR 4/24/2008 M ALE 254 168 HR021 HR 4/24/2008 M ALE 250 140 HR022 HR 4/24/2008 M ALE 252 120 HR023 HR 4/24/2008 M ALE 254 150 HR024 HR 4/24/2008 M ALE 244 122 HR025 HR 4/24/2008 M ALE 244 114 HR026 HR 5/16/2008 M ALE 264 170 HR027 HR 5/16/2008 F ALE 267 154 HR028 HR 5/16/2008 M ALE 255 146 HR029 HR 5/16/2008 F ALE 249 134 HR030 HR 5/16/2008 F ALE 248 128 HR031 HR 5/16/2008 F ALE 244 122 HR032 HR 5/16/2008 M ALE 264 148 HR033 HR 5/16/2008 M ALE 256 136 HR034 HR 5/16/2008 M ALE 232 108 HR035 HR 5/16/2008 M ALE 267 164 HR036 HR 5/16/2008 M ALE 234 112 HR037 HR 5/16/2008 M ALE 248 134 HR038 HR 5/16/2008 M ALE 252 132 HR039 HR 5/16/2008 F ALE 267 146 HR901 HR 4/30/2009 M ALE 256 122 HR902 HR 4/30/2009 F ALE 274 176 HR903 HR 4/30/2009 M ALE 259 134 HR904 HR 4/30/2009 M ALE 260 140 HR905 HR 4/30/2009 M ALE 231 110 HR906 HR 4/30/2009 M ALE 269 150 HR907 HR 4/30/2009 M ALE 261 164 HR908 HR 4/30/2009 M ALE 264 158 HR909 HR 4/30/2009 M ALE 218 88 HR910 HR 4/30/2009 M ALE 255 142 HR911 HR 4/30/2009 M ALE 266 152 HR912 HR 4/30/2009 M ALE 235 120 HR913 HR 4/30/2009 M ALE 262 176 HR914 HR 5/6/2009 M ALE 255 142 HR915 HR 5/6/2009 M ALE 265 148 HR916 HR 5/6/2009 M ALE 281 168 HR917 HR 5/6/2009 M ALE 254 154 HR918 HR 5/6/2009 M ALE 249 124 HR919 HR 5/6/2009 M ALE 276 180 HR920 HR 5/6/2009 M ALE 227 98 HR921 HR 5/6/2009 M ALE 235 114 HR922 HR 5/6/2009 M ALE 233 92 HR923 HR 5/6/2009 M ALE 229 104 HR924 HR 5/6/2009 M ALE 242 122
100 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) HR925 HR 5/13/2009 M ALE 267 154 HR926 HR 5/13/2009 M ALE 230 98 HR927 HR 5/13/2009 M ALE 247 122 HR928 HR 5/13/2009 M ALE 258 138 HR929 HR 5/13/2009 M ALE 250 138 HR930 HR 5/13/2009 M ALE 238 104 HR931 HR 5/13/2009 M ALE 245 114 HR932 HR 5/13/2009 M ALE 261 132 HR933 HR 5/13/2009 M ALE 218 80 HR934 HR 5/13/2009 M ALE 236 118 MR801 MR 4/2/2008 M ALE 269 188 MR802 MR 4/2/2008 F ALE 262 164 MR803 MR 4/2/2008 M ALE 270 188 MR804 MR 4/2/2008 M ALE 257 166 MR805 MR 4/2/2008 F ALE 280 212 MR806 MR 4/2/2008 F ALE 267 180 MR807 MR 4/2/2008 M ALE 263 162 MR808 MR 4/2/2008 F ALE 272 200 MR809 MR 4/2/2008 F ALE 259 166 MR810 MR 4/2/2008 F ALE 265 190 MR811 MR 4/2/2008 F ALE 275 188 MR812 MR 4/2/2008 F ALE 263 164 MR813 MR 4/10/2008 F ALE 284 217 MR814 MR 4/10/2008 M ALE 257 158 MR815 MR 4/10/2008 M ALE 273 194 MR816 MR 4/10/2008 F ALE 294 260 MR817 MR 4/10/2008 F ALE 269 174 MR818 MR 4/10/2008 M ALE 246 148 MR819 MR 4/10/2008 M ALE 262 168 MR820 MR 4/10/2008 F ALE 268 194 MR821 MR 4/10/2008 M ALE 254 166 MR822 MR 4/10/2008 M ALE 264 170 MR823 MR 4/10/2008 M ALE 278 214 MR824 MR 4/10/2008 M ALE 266 176 MR825 MR 4/10/2008 M ALE 236 132 MR826 MR 4/24/2008 F ALE 246 154 MR827 MR 4/24/2008 F ALE 268 198 MR828 MR 4/24/2008 F ALE 258 172 MR829 MR 4/24/2008 F ALE 259 176 MR830 MR 4/24/2008 F ALE 259 190 MR831 MR 4/24/2008 M ALE 252 170 MR832 MR 4/24/2008 F ALE 262 193 MR833 MR 4/24/2008 F ALE 254 176 MR834 MR 4/24/2008 M ALE 266 178 MR835 MR 4/24/2008 F ALE 252 172 MR901 MR 4/6/2009 F ALE 260 156 MR902 MR 4/6/2009 F ALE 282 188 MR903 MR 4/6/2009 F ALE 289 222 MR904 MR 4/6/2009 F ALE 269 176 MR905 MR 4/6/2009 F ALE 274 200
101 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) MR906 MR 4/6/2009 M ALE 263 170 MR907 MR 4/6/2009 M ALE 252 148 MR908 MR 4/6/2009 F ALE 290 218 MR909 MR 4/6/2009 F ALE 276 180 MR910 MR 4/6/2009 M ALE 275 181 MR911 MR 4/22/2009 M ALE 269 182 MR912 MR 4/22/2009 M ALE 253 246 MR913 MR 4/22/2009 F ALE 278 206 MR914 MR 4/22/2009 M ALE 244 118 MR915 MR 4/22/2009 F ALE 273 200 MR916 MR 4/22/2009 M ALE 278 188 MR917 MR 4/22/2009 F ALE 289 228 MR918 MR 4/22/2009 F ALE 293 220 MR919 MR 4/22/2009 M ALE 233 110 MR920 MR 4/22/2009 F ALE 264 180 MR921 MR 4/22/2009 F ALE 272 188 MR922 MR 4/22/2009 F ALE 288 232 MR923 MR 5/7/2009 M ALE 238 128 MR924 MR 5/7/2009 F ALE 243 140 MR925 MR 5/7/2009 M ALE 261 164 MR926 MR 5/7/2009 F ALE 276 208 MR927 MR 5/7/2009 M ALE 231 114 MR928 MR 5/7/2009 F ALE 259 152 MR929 MR 5/7/2009 M ALE 225 104 MR930 MR 5/7/2009 F ALE 245 134 MR931 MR 5/7/2009 F ALE 269 188 MR932 MR 5/7/2009 F ALE 288 238 PB801 PB 4/7/2008 M ALE 278 192 PB802 PB 4/7/2008 M ALE 278 188 PB803 PB 4/7/2008 F ALE 296 270 PB804 PB 4/7/2008 M ALE 258 158 PB805 PB 4/7/2008 M ALE 271 172 PB806 PB 4/7/2008 M ALE 255 154 PB807 PB 4/7/2008 M ALE 261 174 PB808 PB 4/7/2008 M ALE 264 170 PB809 PB 4/7/2008 M ALE 258 160 PB810 PB 4/7/2008 M ALE 278 210 PB811 PB 4/7/2008 M ALE 272 195 PB812 PB 4/7/2008 M ALE 257 152 PB813 PB 4/7/2008 M ALE 275 200 PB814 PB 4/7/2008 M ALE 254 145 PB815 PB 4/7/2008 M ALE 272 190 PB816 PB 4/7/2008 M ALE 254 130 PB819 PB 4/14/2008 M ALE 286 210 PB820 PB 4/14/2008 M ALE 242 132 PB821 PB 4/14/2008 M ALE 250 138 PB822 PB 4/14/2008 M ALE 263 160 PB823 PB 4/14/2008 M ALE 248 140 PB824 PB 4/14/2008 M ALE 257 160 PB825 PB 4/14/2008 M ALE 263 142
102 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) PB826 PB 4/14/2008 F ALE 272 220 PB827 PB 4/14/2008 M ALE 288 236 PB828 PB 4/14/2008 M ALE 266 167 PB829 PB 4/14/2008 F ALE 263 160 PB830 PB 4/14/2008 F ALE 284 244 PB831 PB 4/14/2008 F ALE 284 230 PB832 PB 4/22/2008 M ALE 271 158 PB833 PB 4/22/2008 M ALE 267 152 PB834 PB 4/22/2008 F ALE 281 242 PB835 PB 4/22/2008 M ALE 289 172 PB836 PB 4/22/2008 M ALE 257 146 PB837 PB 4/22/2008 F ALE 244 134 PB838 PB 4/22/2008 M ALE 238 118 PB839 PB 4/22/2008 M ALE 278 184 PB840 PB 4/22/2008 M ALE 261 148 PB841 PB 4/22/2008 M ALE 250 132 PB901 PB 4/2/2009 M ALE 281 208 PB902 PB 4/2/2009 M ALE 267 170 PB903 PB 4/2/2009 M ALE 279 208 PB904 PB 4/2/2009 M ALE 269 176 PB905 PB 4/2/2009 M ALE 273 170 PB906 PB 4/2/2009 M ALE 274 174 PB907 PB 4/2/2009 F ALE 296 256 PB908 PB 4/2/2009 M ALE 264 168 PB909 PB 4/2/2009 M ALE 256 160 PB910 PB 4/2/2009 M ALE 283 288 PB911 PB 4/2/2009 F ALE 288 232 PB912 PB 4/2/2009 M ALE 262 150 PB913 PB 4/2/2009 F ALE 294 230 PB914 PB 4/20/2009 M ALE 276 184 PB915 PB 4/20/2009 F ALE 293 216 PB916 PB 4/20/2009 M ALE 253 231 PB917 PB 4/20/2009 F ALE 287 200 PB918 PB 4/20/2009 F ALE 250 130 PB919 PB 4/20/2009 M ALE 274 168 PB920 PB 4/20/2009 M ALE 243 122 PB921 PB 4/20/2009 F ALE 281 180 PB922 PB 4/20/2009 F ALE 303 260 PB923 PB 4/20/2009 M ALE 248 126 PB924 PB 4/20/2009 F ALE 266 182 PB925 PB 4/20/2009 M ALE 235 105 PB926 PB 4/20/2009 M ALE 264 152 PB927 PB 4/20/2009 F ALE 278 186 PB928 PB 4/20/2009 M ALE 287 198 PB929 PB 4/27/2009 M ALE 254 128 PB930 PB 4/27/2009 F ALE 291 220 PB931 PB 4/27/2009 M ALE 264 146 PB932 PB 4/27/2009 M ALE 237 108 PB934 PB 4/27/2009 M ALE 226 88 PB935 PB 4/27/2009 M ALE 274 152
103 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) PB936 PB 4/27/2009 M ALE 266 150 PB937 PB 4/27/2009 M ALE 281 196 PB938 PB 4/27/2009 F ALE 296 192 PB939 PB 4/27/2009 M ALE 249 224 PB940 PB 4/27/2009 M ALE 259 140 PR801 PR 4/10/2008 M ALE 254 166 PR802 PR 4/10/2008 M ALE 240 134 PR803 PR 4/10/2008 F ALE 284 220 PR804 PR 4/10/2008 M ALE 263 140 PR805 PR 4/10/2008 F ALE 266 176 PR806 PR 4/10/2008 M ALE 257 154 PR807 PR 4/10/2008 F ALE 262 164 PR808 PR 4/10/2008 M ALE 254 150 PR809 PR 4/10/2008 F ALE 243 120 PR810 PR 4/10/2008 M ALE 258 178 PR811 PR 4/10/2008 M ALE 264 168 PR812 PR 4/10/2008 M ALE 237 126 PR813 PR 4/10/2008 F ALE 270 182 PR814 PR 4/17/2008 F ALE 276 198 PR815 PR 4/17/2008 F ALE 256 160 PR816 PR 4/17/2008 M ALE 250 132 PR817 PR 4/17/2008 F ALE 270 190 PR818 PR 4/17/2008 M ALE 263 160 PR819 PR 4/17/2008 M ALE 242 130 PR820 PR 4/17/2008 F ALE 249 148 PR821 PR 4/17/2008 F ALE 267 182 PR822 PR 4/17/2008 M ALE 264 158 PR823 PR 4/17/2008 M ALE 254 142 PR824 PR 4/17/2008 M ALE 269 158 PR825 PR 4/17/2008 M ALE 250 142 PR826 PR 4/17/2008 M ALE 232 104 PR827 PR 4/17/2008 M ALE 236 104 PR828 PR 4/17/2008 M ALE 228 98 PR829 PR 4/24/2008 F ALE 259 172 PR830 PR 4/24/2008 F ALE 231 122 PR831 PR 4/24/2008 M ALE 240 120 PR832 PR 4/24/2008 F ALE 248 156 PR833 PR 4/24/2008 M ALE 244 126 PR834 PR 4/24/2008 M ALE 235 120 PR835 PR 4/24/2008 F ALE 264 274 PR836 PR 4/24/2008 F ALE 263 274 PR837 PR 4/24/2008 M ALE 250 156 PR838 PR 4/24/2008 M ALE 246 128 PR901 PR 4/20/2009 F ALE 288 220 PR902 PR 4/20/2009 M ALE 234 116 PR903 PR 4/20/2009 M ALE 278 182 PR904 PR 4/20/2009 M ALE 282 204 PR905 PR 4/20/2009 F ALE 296 252 PR906 PR 4/20/2009 M ALE 271 170 PR907 PR 4/20/2009 M ALE 246 128
104 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) PR908 PR 4/20/2009 M ALE 256 138 PR909 PR 4/20/2009 F ALE 263 170 PR910 PR 4/20/2009 M ALE 237 110 PR911 PR 4/20/2009 F ALE 273 190 PR912 PR 4/20/2009 F ALE 268 172 PR913 PR 4/20/2009 M ALE 250 142 PR914 PR 4/20/2009 F ALE 293 232 PR915 PR 4/28/2009 F ALE 284 184 PR916 PR 4/28/2009 F ALE 247 120 PR917 PR 4/28/2009 F ALE 279 206 PR918 PR 4/28/2009 M ALE 251 144 PR919 PR 4/28/2009 M ALE 273 170 PR920 PR 4/28/2009 M ALE 228 132 PR921 PR 4/28/2009 M ALE 257 162 PR922 PR 4/28/2009 M ALE 263 146 PR923 PR 4/28/2009 M ALE 232 112 PR924 PR 4/28/2009 M ALE 287 184 PR925 PR 4/28/2009 F ALE 268 178 PR926 PR 5/6/2009 M ALE 229 102 PR927 PR 5/6/2009 F ALE 259 154 PR928 PR 5/6/2009 F ALE 282 208 PR929 PR 5/6/2009 M ALE 264 148 PR930 PR 5/6/2009 F ALE 268 186 QR801 QR 4/17/2008 M ALE 257 146 QR802 QR 4/17/2008 M ALE 254 140 QR803 QR 4/17/2008 M ALE 264 158 QR804 QR 4/17/2008 M ALE 266 178 QR805 QR 4/17/2008 M ALE 247 128 QR806 QR 4/17/2008 F ALE 275 202 QR807 QR 4/17/2008 M ALE 252 140 QR808 QR 4/17/2008 M ALE 267 168 QR809 QR 4/17/2008 F ALE 273 182 QR810 QR 4/17/2008 M ALE 257 154 QR811 QR 4/17/2008 M ALE 228 104 QR812 QR 4/17/2008 M ALE 239 124 QR813 QR 4/24/2008 M ALE 244 120 QR814 QR 4/24/2008 F ALE 278 198 QR815 QR 4/24/2008 M ALE 270 184 QR816 QR 4/24/2008 F ALE 268 176 QR817 QR 4/24/2008 M ALE 246 140 QR818 QR 4/24/2008 F ALE 255 154 QR819 QR 4/24/2008 M ALE 258 158 QR820 QR 4/24/2008 F ALE 273 196 QR821 QR 4/24/2008 M ALE 253 140 QR822 QR 4/24/2008 M ALE 264 154 QR823 QR 4/24/2008 F ALE 265 168 QR824 QR 4/24/2008 M ALE 256 176 QR825 QR 4/24/2008 F ALE 272 168 QR826 QR 4/24/2008 F ALE 251 248 QR827 QR 4/24/2008 M ALE 247 124
105 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) QR828 QR 4/24/2008 F ALE 266 180 QR829 QR 4/24/2008 M ALE 269 180 QR830 QR 4/24/2008 M ALE 242 130 QR831 QR 5/19/2008 F BBH 257 166 QR832 QR 5/19/2008 F BBH 232 118 QR833 QR 5/19/2008 M BBH 235 112 QR834 QR 5/19/2008 M BBH 247 134 QR835 QR 5/19/2008 M BBH 234 108 QR836 QR 5/19/2008 F BBH 252 152 QR837 QR 5/19/2008 F BBH 244 224 QR838 QR 5/19/2008 M BBH 238 112 QR839 QR 5/19/2008 F BBH 243 128 QR840 QR 5/19/2008 M BBH 238 118 QR841 QR 5/19/2008 F BBH 237 106 QR842 QR 5/19/2008 F BBH 241 120 QR843 QR 5/19/2008 M BBH 234 112 QR844 QR 5/19/2008 F BBH 243 130 QR845 QR 5/19/2008 M BBH 240 118 QR846 QR 5/28/2008 M BBH 236 102 QR847 QR 5/28/2008 F BBH 234 104 QR848 QR 5/28/2008 M BBH 219 94 QR849 QR 5/28/2008 F BBH 237 118 QR850 QR 5/28/2008 M BBH 239 110 QR851 QR 5/28/2008 F BBH 242 116 QR852 QR 5/28/2008 M BBH 241 130 QR853 QR 5/28/2008 M BBH 242 110 QR854 QR 5/28/2008 M BBH 237 94 QR855 QR 5/28/2008 M BBH 229 96 QR856 QR 5/28/2008 F BBH 251 148 QR857 QR 5/28/2008 M BBH 231 112 QR858 QR 5/28/2008 M BBH 227 96 QR859 QR 5/28/2008 M BBH 262 160 QR860 QR 5/28/2008 F BBH 267 174 QR861 QR 5/28/2008 NR BBH 247 148 QR901 QR 4/24/2009 M ALE 268 164 QR902 QR 4/24/2009 M ALE 247 138 QR903 QR 4/24/2009 M ALE 241 120 QR904 QR 4/24/2009 F ALE 276 190 QR905 QR 4/24/2009 M ALE 228 98 QR906 QR 4/24/2009 F ALE 259 146 QR907 QR 4/24/2009 M ALE 233 112 QR908 QR 4/24/2009 M ALE 247 132 QR909 QR 4/24/2009 M ALE 271 172 QR910 QR 4/24/2009 F ALE 254 158 QR911 QR 4/24/2009 F ALE 263 164 QR912 QR 4/24/2009 M ALE 259 148 QR913 QR 4/24/2009 M ALE 239 114 QR914 QR 4/28/2009 M ALE 263 146 QR915 QR 4/28/2009 F ALE 258 146 QR916 QR 4/28/2009 M ALE 232 120
106 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) QR917 QR 4/28/2009 F ALE 269 172 QR918 QR 4/28/2009 F ALE 251 144 QR919 QR 4/28/2009 M ALE 248 130 QR920 QR 4/28/2009 F ALE 243 118 QR921 QR 4/28/2009 M ALE 239 106 QR922 QR 4/28/2009 F ALE 242 118 QR923 QR 4/28/2009 M ALE 259 156 QR924 QR 4/28/2009 M ALE 245 112 QR925 QR 4/28/2009 M ALE 236 108 QR926 QR 4/28/2009 M ALE 243 124 QR927 QR 5/5/2209 M ALE 232 102 QR928 QR 5/5/2209 F ALE 256 164 QR929 QR 5/5/2209 M BBH 222 98 QR930 QR 5/5/2209 M ALE 231 104 QR931 QR 5/5/2209 F ALE 283 232 QR932 QR 5/5/2209 F ALE 271 200 QR933 QR 5/5/2209 F ALE 252 142 QR934 QR 5/5/2209 M ALE 268 194 QR935 QR 5/5/2209 F ALE 260 168 QR936 QR 5/5/2209 M ALE 237 122 QR937 QR 5/5/2209 F ALE 242 114 QR938 QR 5/5/2209 F ALE 249 114 QR939 QR 5/13/2009 M BBH 226 94 QR940 QR 5/13/2009 M BBH 240 116 QR941 QR 5/13/2009 M BBH 241 120 QR942 QR 5/13/2009 F BBH 259 170 QR943 QR 5/13/2009 F BBH 248 134 QR944 QR 5/13/2009 M BBH 231 104 QR945 QR 5/13/2009 F BBH 263 164 QR946 QR 5/13/2009 M BBH 250 136 QR947 QR 5/13/2009 M BBH 237 116 QR948 QR 5/13/2009 F BBH 236 100 QR953 QR 5/19/2009 M BBH 263 150 QR954 QR 5/19/2009 M BBH 244 118 QR955 QR 5/19/2009 M BBH 240 104 QR956 QR 5/19/2009 M BBH 243 128 QR957 QR 5/19/2009 F BBH 251 134 QR958 QR 5/19/2009 M BBH 238 104 QR959 QR 5/19/2009 F BBH 258 162 QR960 QR 5/19/2009 M BBH 244 120 QR961 QR 5/19/2009 M BBH 232 106 QR962 QR 5/19/2009 F BBH 250 146 QR963 QR 5/19/2009 F BBH 258 162 QR964 QR 5/19/2009 F BBH 239 122 QR965 QR 5/19/2009 F BBH 230 106 QR966 QR 5/19/2009 F BBH 234 120 QR967 QR 5/19/2009 F BBH 252 134 QR968 QR 5/19/2009 F BBH 268 194 QR969 QR 5/19/2009 M BBH 210 80 QR970 QR 5/19/2009 F BBH 247 126
107 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) QR971 QR 5/19/2009 M BBH 223 92 WC801 WC 5/9/2008 F ALE 262 150 WC802 WC 5/9/2008 M BBH 238 124 WC803 WC 5/9/2008 F BBH 241 116 WC804 WC 5/9/2008 F BBH 238 116 WC805 WC 5/9/2008 F ALE 263 160 WC806 WC 5/9/2008 M BBH 239 128 WC807 WC 5/9/2008 M BBH 244 130 WC808 WC 5/9/2008 F BBH 248 142 WC809 WC 5/9/2008 M BBH 257 150 WC810 WC 5/9/2008 F ALE 257 142 WC811 WC 5/9/2008 F BBH 255 146 WC812 WC 5/9/2008 F BBH 262 142 WC813 WC 5/9/2008 F BBH 285 217 WC814 WC 5/9/2008 M BBH 263 148 WC815 WC 5/9/2008 F BBH 259 194 WC816 WC 5/9/2008 F BBH 248 124 WC817 WC 5/9/2008 F BBH 277 196 WC818 WC 5/9/2008 F BBH 265 180 WC819 WC 5/9/2008 F BBH 262 164 WC820 WC 5/9/2008 F BBH 253 168 WC821 WC 5/9/2008 M BBH 239 136 WC822 WC 5/9/2008 M ALE 262 152 WC823 WC 5/9/2008 F BBH 267 168 WC824 WC 5/9/2008 F BBH 286 184 WC825 WC 5/9/2008 M BBH 241 126 WC826 WC 5/9/2008 F BBH 257 136 WC827 WC 5/9/2008 M ALE 257 150 WC828 WC 5/9/2008 F BBH 259 172 WC829 WC 5/9/2008 M ALE 267 164 WC830 WC 5/9/2008 F ALE 262 150 WC831 WC 5/9/2008 M BBH 233 120 WC832 WC 5/9/2008 F BBH 297 210 WC833 WC 5/9/2008 F BBH 258 170 WC834 WC 5/9/2008 M BBH 241 126 WC835 WC 5/9/2008 M BBH 233 120 WC836 WC 5/9/2008 M BBH 230 104 WC837 WC 5/9/2008 M BBH 239 130 WC838 WC 6/4/2008 M BBH 249 120 WC839 WC 6/4/2008 M BBH 228 96 WC840 WC 6/4/2008 F BBH 260 132 WC841 WC 6/4/2008 M BBH 235 100 WC842 WC 6/4/2008 M BBH 255 132 WC843 WC 6/4/2008 F BBH 243 112 WC844 WC 6/4/2008 M BBH 234 104 WC845 WC 6/4/2008 F BBH 236 116 WC846 WC 6/4/2008 M BBH 224 94 WC847 WC 6/4/2008 F BBH 265 146 WC848 WC 6/4/2008 M BBH 258 142 WC849 WC 6/4/2008 M BBH 234 106
108 Date Total Length FISH ID Site Collected Sex Species (mm) Weight (g) WC850 WC 6/4/2008 M BBH 248 114 WC901 WC 4/23/2009 F BBH 266 164 WC902 WC 4/23/2009 M BBH 252 150 WC903 WC 4/23/2009 M ALE 235 110 WC904 WC 4/23/2009 M BBH 254 156 WC905 WC 4/28/2009 M BBH 219 88 WC906 WC 4/28/2009 M BBH 240 144 WC907 WC 4/28/2009 M BBH 252 152 WC908 WC 4/28/2009 F BBH 307 298 WC909 WC 4/28/2009 M BBH 245 142 WC910 WC 4/28/2009 M BBH 268 172 WC911 WC 4/28/2009 M BBH 256 160 WC912 WC 4/28/2009 M BBH 237 102 WC913 WC 4/28/2009 F BBH 284 230 WC914 WC 4/28/2009 M BBH 226 104 WC915 WC 4/28/2009 M BBH 261 168 WC916 WC 4/28/2009 F BBH 272 178 WC917 WC 4/28/2009 M BBH 251 160 WC918 WC 4/28/2009 F ALE 276 184 WC919 WC 4/28/2009 F BBH 275 170 WC920 WC 4/28/2009 M BBH 223 96 WC921 WC 4/28/2009 M BBH 252 154 WC921 WC 5/7/2009 M BBH 242 112 WC922 WC 5/7/2009 F BBH 283 206 WC923 WC 5/7/2009 F BBH 293 248 WC924 WC 5/7/2009 F BBH 256 136 WC925 WC 5/7/2009 F BBH 273 196 WC926 WC 5/7/2009 F BBH 289 218 WC927 WC 5/7/2009 M BBH 244 124 WC928 WC 5/7/2009 M BBH 238 112 WC929 WC 5/7/2009 M BBH 234 116 WC930 WC 5/7/2009 F BBH 277 184 WC931 WC 5/7/2009 M BBH 258 148 WC932 WC 5/7/2009 F BBH 262 160
109
APPENDIX B
110
Means Site Species Lifestage Sr Ba Bride Brook Alewife Adult 1365.043 8.410 Eightmile River Alewife Adult 1554.743 5.174 Housatonic River Alewife Adult 844.8593 3.217 Mianus River Alewife Adult 1055.675 9.484 Poquetanuck Brook Alewife Adult 3554.710 9.714 Pequonnock River Alewife Adult 964.915 4.360 Quinnipiac River Alewife Adult 1247.957 8.950 Shetucket River Alewife Adult 3096.731 3.912 Bride Brook Alewife Age 0 1045.239 29.448 Eightmile River Alewife Age 0 813.371 13.742 Housatonic River Alewife Age 0 279.953 2.702 Mianus River Alewife Age 0 604.007 5.388 Pequonnock River Alewife Age 0 701.491 6.015 Quinnipiac River Alewife Age 0 469.596 11.793 Shetucket River Alewife Age 0 699.769 4.914 Eightmile River Blueback Adult 901.267 7.090 Farmington River Blueback Adult 729.969 10.067 Quinnipiac River Blueback Adult 437.527 11.935 Wethersfield Cove Blueback Adult 850.019 8.322 Eightmile River Blueback Age 0 590.446 9.109 Housatonic River Blueback Age 0 190.204 2.689 Mianus River Blueback Age 0 592.412 16.268 Quinnipiac River Blueback Age 0 320.122 11.214 Wethersfield Cove Blueback Age 0 530.902 12.490
111
APPENDIX C
112 ID Site Sex Species TL WEIGHT AGE YC AEM AAF Li1 LAM AAM SC PC2 BB818 BRIDE F ALE 249 150 3 2005 61 0 183.051 249 3 N -0.04566 BB830 BRIDE F ALE 251 158 3 2005 79 0 180.858 251 3 N -0.12226 BB912 BRIDE F ALE 276 198 5 2004 57 0 195.035 276 5 N 0.58694 BB942 BRIDE F ALE 230 104 2 2007 54 0 209.815 230 2 N -0.15132 BB951 BRIDE M ALE 262 168 3 2006 39 10 191.114 262 3 N -0.54355 EM805 EIGHTMILE M ALE 274 176 4 2004 65 10 200.722 261 3 Y -0.50525 EM883 EIGHTMILE M ALE 217 96 2 2006 68 0 187.489 217 2 N 0.346559 EM902 EIGHTMILE M ALE 232 106 2 2007 52 15 200.579 232 2 N -0.22792 EM917 EIGHTMILE F ALE 270 202 3 2006 43 0 214.751 270 3 N -0.84994 GR936 SHETUCKET F ALE 240 124 3 2006 30 0 192.87 240 3 N 0.299024 HR909 HOUSATONIC M ALE 218 88 2 2007 73 15 200.178 218 2 N 0.308261 HR920 HOUSATONIC M ALE 227 98 2 2007 55 0 188.542 227 2 N -0.03643 HR924 HOUSATONIC M ALE 242 122 3 2006 50 0 208.605 242 3 N 0.222427 MR818 MIANUS M ALE 246 148 3 2005 47 5 203.815 246 3 N 0.069232 MR901 MIANUS F ALE 260 156 4 2005 44 0 174.548 260 4 N 0.366385 MR902 MIANUS F ALE 282 188 4 2005 55 15 203.792 282 4 N -0.47619 MR912 MIANUS M ALE 253 246 2 2005 40 0 237.197 253 2 N -1.03219 PR838 PEQUONNOCK M ALE 246 128 3 2005 37 20 211.772 246 3 N 0.069232 PR907 PEQUONNOCK M ALE 246 128 4 2005 82 0 172.655 246 4 N 0.902565 PR913 PEQUONNOCK M ALE 250 142 4 2005 58 0 170.67 250 4 N 0.749371 PR918 PEQUONNOCK M ALE 251 144 5 2004 139 0 134.213 227 4 Y 1.630239 PR924 PEQUONNOCK M ALE 287 184 4 2005 31 0 208.836 276 3 Y -1.07973 QR904 QUINNIPIAC F ALE 276 190 4 2005 55 0 232.349 276 4 N -0.24639 QR916 QUINNIPIAC M ALE 232 120 3 2006 56 10 186.943 232 3 N 0.605413 QR927 QUINNIPIAC M ALE 232 102 2 2007 64 10 210.3 232 2 N -0.22792 QR937 QUINNIPIAC F ALE 242 114 2 2007 73 20 203.871 242 2 N -0.61091 EM871 EIGHTMILE M BBH 234 108 3 2005 37 10 152.882 234 3 N 0.233687 EM937 EIGHTMILE M BBH 262 142 4 2005 60 10 187.383 262 4 N -0.68854 FR808 FARMINGTON M BBH 238 110 4 2004 119 0 103.965 238 4 N 0.710341 FR903 FARMINGTON F BBH 269 164 5 2004 61 10 167.265 245 3 Y -0.40747 ID Site Sex Species TL WEIGHT AGE YC AEM AAF Li1 LAM AAM SC PC2 FR940 FARMINGTON M BBH 261 146 5 2004 58 10 127.339 261 5 N 0.079548
113 QR855 QUINNIPIAC M BBH 229 96 3 2005 109 0 135.144 229 3 N 0.52512 QR939 QUINNIPIAC M BBH 226 94 3 2006 134 0 126.359 226 3 N 0.69998 QR943 QUINNIPIAC F BBH 248 134 4 2005 136 0 142.051 248 4 N 0.127474 QR956 QUINNIPIAC M BBH 243 128 3 2006 76 0 179.166 243 3 N -0.29089 QR958 QUINNIPIAC M BBH 238 104 2 2007 40 0 187.559 238 2 N -0.70926 QR963 QUINNIPIAC M BBH 258 162 5 2004 93 0 171.088 258 5 N 0.254408 WC841 WETHERSFIELD M BBH 235 100 2 2006 59 10 123.048 235 2 N -0.5344
114
APPENDIX D
115
ID SITE Sex Species Lc Age Sc Inc. Si Li BB818 Bride F ALE 249 3 1925.01 1 1415.16 183.051 BB818 Bride F ALE 249 3 1925.01 2 1733.79 224.265 BB818 Bride F ALE 249 3 1925.01 3 1925.01 249 BB830 Bride F ALE 251 3 2317.36 1 1669.77 180.858 BB830 Bride F ALE 251 3 2317.36 2 2145.66 232.403 BB830 Bride F ALE 251 3 2317.36 3 2317.36 251 BB912 Bride F ALE 276 5 2267.49 1 1602.32 195.035 BB912 Bride F ALE 276 5 2267.49 2 1842.27 224.242 BB912 Bride F ALE 276 5 2267.49 3 2021.28 246.03 BB912 Bride F ALE 276 5 2267.49 4 2162.67 263.241 BB912 Bride F ALE 276 5 2267.49 5 2267.49 276 BB942 Bride F ALE 230 3 2133.92 1 1946.65 209.815 BB942 Bride F ALE 230 2 2133.92 2 2133.92 230 BB951 Bride M ALE 262 2 2257.32 1 1646.59 191.114 BB951 Bride M ALE 262 3 2257.32 2 1988.76 230.83 BB951 Bride M ALE 262 3 2257.32 3 2257.32 262 EM805 Eightmile M ALE 274 4 2159.31 1 1581.83 200.722 EM805 Eightmile M ALE 274 4 2159.31 2 1851.07 234.886 EM805 Eightmile M ALE 274 4 2159.31 3 2055.3 260.801 EM805 Eightmile M ALE 274 4 2159.31 4 2159.31 274 EM871 Eightmile M BBH 234 3 2056.92 1 1343.88 152.882 EM871 Eightmile M BBH 234 3 2056.92 2 1897.6 215.875 EM871 Eightmile M BBH 234 3 2056.92 3 2056.92 234 EM883 Eightmile M ALE 217 2 2290.93 1 1979.38 187.489 EM883 Eightmile M ALE 217 2 2290.93 2 2290.93 217 EM902 Eightmile M ALE 232 2 2630.48 1 2274.22 200.579 EM902 Eightmile M ALE 232 2 2630.48 2 2630.48 232 EM917 Eightmile F ALE 270 3 2779.42 1 2210.68 214.751 EM917 Eightmile F ALE 270 3 2779.42 2 2576.45 250.283 EM917 Eightmile F ALE 270 3 2779.42 3 2779.42 270 EM937 Eightmile M BBH 262 4 2480.13 1 1773.79 187.383 EM937 Eightmile M BBH 262 4 2480.13 2 2178.29 230.113 EM937 Eightmile M BBH 262 4 2480.13 3 2408.36 254.418 EM937 Eightmile M BBH 262 4 2480.13 4 2480.72 262.062 FR808 Farmington M BBH 238 4 1778.72 1 776.99 103.965 FR808 Farmington M BBH 238 4 1778.72 2 1330.87 178.076 FR808 Farmington M BBH 238 4 1778.72 3 1636.79 219.008 FR808 Farmington M BBH 238 4 1778.72 4 1778.72 238 FR903 Farmington F BBH 269 5 2137.83 1 1329.31 167.265 FR903 Farmington F BBH 269 5 2137.83 2 1768.22 222.492 FR903 Farmington F BBH 269 5 2137.83 3 1949.87 245.35 FR903 Farmington F BBH 269 5 2137.83 4 2077.99 261.471 FR903 Farmington F BBH 269 5 2137.83 5 2137.83 269 FR940 Farmington M BBH 261 5 2043.95 1 997.22 127.339 ID SITE Sex Species Lc Age Sc Inc. Si Li FR940 Farmington M BBH 261 5 2043.95 2 1371.4 175.12 FR940 Farmington M BBH 261 5 2043.95 3 1674.23 213.789 FR940 Farmington M BBH 261 5 2043.95 4 1943.16 248.129
116 FR940 Farmington M BBH 261 5 2043.95 5 2043.95 261 GR936 Shetucket F ALE 240 3 2200.39 1 1768.28 192.87 GR936 Shetucket F ALE 240 3 2200.39 2 2080.62 226.936 GR936 Shetucket F ALE 240 3 2200.39 3 2200.39 240 HR909 Housatonic M ALE 218 2 1611.19 1 1479.47 200.178 HR909 Housatonic M ALE 218 2 1611.19 2 1611.19 218 HR920 Housatonic M ALE 227 2 1989.7 1 1652.61 188.542 HR920 Housatonic M ALE 227 2 1989.7 2 1989.7 227 HR924 Housatonic M ALE 242 3 2225.35 1 1918.26 208.605 HR924 Housatonic M ALE 242 3 2225.35 2 2163.4 235.263 HR924 Housatonic M ALE 242 3 2225.35 3 2225.35 242 MR818 Mianus M ALE 246 3 2186.01 1 1811.14 203.815 MR818 Mianus M ALE 246 3 2186.01 2 2082.07 234.303 MR818 Mianus M ALE 246 3 2186.01 3 2186.01 246 MR901 Mianus F ALE 260 4 2072.19 1 1391.15 174.548 MR901 Mianus F ALE 260 4 2072.19 2 1748.67 219.407 MR901 Mianus F ALE 260 4 2072.19 3 1910.15 239.668 MR901 Mianus F ALE 260 4 2072.19 4 2072.19 260 MR902 Mianus F ALE 282 4 1713.07 1 1237.98 203.792 MR902 Mianus F ALE 282 4 1713.07 2 1497.8 246.562 MR902 Mianus F ALE 282 4 1713.07 3 1644.84 270.767 MR902 Mianus F ALE 282 4 1713.07 4 1713.07 282 MR912 Mianus M ALE 253 2 2237.63 1 2097.85 237.197 MR912 Mianus M ALE 253 2 2237.63 2 2237.63 253 PR838 Pequonnock M ALE 246 3 1952.45 1 1680.79 211.772 PR838 Pequonnock M ALE 246 3 1952.45 2 1861.9 234.591 PR838 Pequonnock M ALE 246 3 1952.45 3 1952.45 246 PR907 Pequonnock M ALE 246 4 1980.08 1 1389.71 172.655 PR907 Pequonnock M ALE 246 4 1980.08 2 1707.62 212.15 PR907 Pequonnock M ALE 246 4 1980.08 3 1868.42 232.128 PR907 Pequonnock M ALE 246 4 1980.08 4 1980.08 246 PR913 Pequonnock M ALE 250 4 2166.51 1 1479.03 170.67 PR913 Pequonnock M ALE 250 4 2166.51 2 1876.38 216.521 PR913 Pequonnock M ALE 250 4 2166.51 3 2106.6 243.086 PR913 Pequonnock M ALE 250 4 2166.51 4 2166.51 250 PR918 Pequonnock M ALE 251 5 2005.13 1 1072.17 134.213 PR918 Pequonnock M ALE 251 5 2005.13 2 1309.11 163.872 PR918 Pequonnock M ALE 251 5 2005.13 3 1601.77 200.508 PR918 Pequonnock M ALE 251 5 2005.13 4 1811.49 226.76 PR918 Pequonnock M ALE 251 5 2005.13 5 2005.13 251 PR924 Pequonnock M ALE 287 4 1955.25 1 1422.74 208.836 PR924 Pequonnock M ALE 287 4 1955.25 2 1692.29 248.402 ID SITE Sex Species Lc Age Sc Inc. Si Li PR924 Pequonnock M ALE 287 4 1955.25 3 1879 275.808 PR924 Pequonnock M ALE 287 4 1955.25 4 1955.25 287 QR855 Quinnipiac M BBH 229 3 1841.03 1 1086.49 135.144 QR855 Quinnipiac M BBH 229 3 1841.03 2 1589.79 197.748 QR855 Quinnipiac M BBH 229 3 1841.03 3 1841.03 229 QR904 Quinnipiac F ALE 276 4 2361.98 1 1988.42 232.349 QR904 Quinnipiac F ALE 276 4 2361.98 2 2207.36 257.932
117 QR904 Quinnipiac F ALE 276 4 2361.98 3 2302.61 269.063 QR904 Quinnipiac F ALE 276 4 2361.98 4 2361.98 276 QR916 Quinnipiac M ALE 232 3 2477.6 1 1996.42 186.943 QR916 Quinnipiac M ALE 232 3 2477.6 2 2347.1 219.78 QR916 Quinnipiac M ALE 232 3 2477.6 3 2477.6 232 QR927 Quinnipiac M ALE 232 2 1854.66 1 1681.18 210.3 QR927 Quinnipiac M ALE 232 2 1854.66 2 1854.66 232 QR937 Quinnipiac F ALE 242 2 2410.53 1 2030.73 203.871 QR937 Quinnipiac F ALE 242 2 2410.53 2 2410.53 242 QR939 Quinnipiac M BBH 226 3 1974.17 1 1103.77 126.359 QR939 Quinnipiac M BBH 226 3 1974.17 2 1654.08 189.356 QR939 Quinnipiac M BBH 226 3 1974.17 3 1974.17 226 QR943 Quinnipiac F BBH 248 4 2247.47 1 1287.32 142.051 QR943 Quinnipiac F BBH 248 4 2247.47 2 1696.25 187.175 QR943 Quinnipiac F BBH 248 4 2247.47 3 2211.55 244.037 QR943 Quinnipiac F BBH 248 4 2247.47 4 2247.47 248 QR956 Quinnipiac M BBH 243 3 2109.48 1 1555.34 179.166 QR956 Quinnipiac M BBH 243 3 2109.48 2 2023.43 233.088 QR956 Quinnipiac M BBH 243 3 2109.48 3 2109.48 243 QR958 Quinnipiac M BBH 238 2 2152.84 2 1696.57 187.559 QR958 Quinnipiac M BBH 238 2 2152.84 3 2152.84 238 QR963 Quinnipiac M BBH 258 5 2654.08 1 1760.01 171.088 QR963 Quinnipiac M BBH 258 5 2654.08 2 2112.23 205.327 QR963 Quinnipiac M BBH 258 5 2654.08 3 2397.97 233.103 QR963 Quinnipiac M BBH 258 5 2654.08 4 2522.97 245.255 QR963 Quinnipiac M BBH 258 5 2654.08 5 2654.08 258 WC841 Wethersfield M BBH 235 2 1905.66 1 1730.63 213.416 WC841 Wethersfield M BBH 235 2 1905.66 2 1905.66 235
118
APPENDIX E
119 COPY OF COLLECTION PERMIT
120