Mechanisms driving recruitment variability in fish: comparisons between the Laurentian Great Lakes and marine systems

ICES Journal of Marine Science ICES Journal of Marine Science (2014), 71(8), 2252– 2267. doi:10.1093/icesjms/fsu080 Contribution to the Special Issue: ‘Commemorating 100 years since Hjort’s 1914 treatise on fluctuations in the great fisheries of northern Europe’ Review Article Mechanisms driving recruitment variability in fish: comparisons between the Laurentian Great Lakes and marine systems Jeremy J. Pritt*, Edward F. Roseman, and Timothy P. O’Brien US Geological Survey, Great Lakes Science Center, 1451 Green Rd., Ann Arbor, MI 48105, USA *Corresponding author: tel: +1-419-530-8386; fax: +1-419-530-8399; e-mail: Pritt, J. J., Roseman, E. F., and O’Brien, T. P. Mechanisms driving recruitment variability in fish: comparisons between the Laurentian Great Lakes and marine systems. – ICES Journal of Marine Science, 71: 2252 –2267. Received 11 December 2013; revised 7 April 2014; accepted 8 April 2014; advance access publication 27 May 2014. In his seminal work, Hjort (in Fluctuations in the great fisheries of Northern Europe. Conseil Parmanent International Pour L’Exploration De La Mar. Rapports et Proces-Verbaux, 20: 1–228, 1914) observed that fish population levels fluctuated widely, year-class strength was set early in life, and egg production by adults could not alone explain variability in year-class strength. These observations laid the foundation for hypotheses on mechanisms driving recruitment variability in marine systems. More recently, researchers have sought to explain year-class strength of important fish in the Laurentian Great Lakes and some of the hypotheses developed for marine fisheries have been transferred to Great Lakes fish. We conducted a literature review to determine the applicability of marine recruitment hypotheses to Great Lakes fish. We found that temperature, interspecific interactions, and spawner effects (abundance, age, and condition of adults) were the most important factors in explaining recruitment variability in Great Lakes fish, whereas relatively fewer studies identified bottom-up trophodynamic factors or hydrodynamic factors as important. Next, we compared recruitment between Great Lakes and Baltic Sea fish populations and found no statistical difference in factors driving recruitment between the two systems, indicating that recruitment hypotheses may often be transferable between Great Lakes and marine systems. Many recruitment hypotheses developed for marine fish have yet to be applied to Great Lakes fish. We suggest that future research on recruitment in the Great Lakes should focus on forecasting the effects of climate change and invasive species. Further, because the Great Lakes are smaller and more enclosed than marine systems, and have abundant fishery-independent data, they are excellent candidates for future hypothesis testing on recruitment in fish. Keywords: larval fish, Laurentian Great Lakes, life history, recruitment. Introduction Predicting year-class strength and subsequent recruitment have long been sought after to improve the management of fisheries (Houde, 2008). Hjort (1914) made several key observations to set the stage for a century’s worth of fisheries research: (i) fish populations experience large fluctuations in abundance, (ii) year-class strength was set early in life, and (iii) egg production (i.e. the number of spawners) alone was insufficient to explain year-class strength variation. Stemming from these observations, much effort has been devoted to determining the factors that drive mortality of the early life stages of fish, particularly in marine systems (Houde, 2009). Much like the important marine fisheries that were the focus of Hjort (1914), freshwater fish in large lentic systems, such as the Laurentian Great Lakes, experience large fluctuations in recruitment. However, research into the dynamics of early life stages of fish in freshwater systems is comparatively newer than that for marine systems and it is unclear whether recruitment hypotheses derived from marine fish are transferable to Great Lakes fish and vice versa. Marine and freshwater fisheries are often in stark contrast to each other. For example, marine fisheries are dominated by commercial users, whereas freshwater fisheries are often dominated by recreational users. Most obviously, marine fisheries are much larger in terms of spatial scale and the abundance of organisms and fishers than freshwater fisheries. However, the Laurentian Great Lakes (hereafter, Great Lakes) have many parallels to marine systems and, in some instances, are more analogous to marine fisheries than other freshwater fisheries. Although recreational angling is more prevalent, substantial commercial fisheries exist in each of the Great Lakes (Kinnunen, 2003). Similar to many marine fisheries, management of Great Lakes fisheries is international and occurs over multiple jurisdictional boundaries (GLFC, 1980). The Great # 2014 International Council for the Exploration of the Sea. Published by Oxford University Press. All rights reserved. For Permissions, please email: Fish Recruitment in the Great Lakes 2253 Lakes are much larger in size than most other freshwater systems and, though they are smaller than large offshore marine fisheries, they are affected by physical and biological processes similar to marine systems. The goal of this paper is to compare early life history paradigms between fish in Great Lakes and marine systems. Our objectives are to: (i) review the biological similarities and differences in early life stages between Great Lakes and marine fish, (ii) review the physical similarities and differences between Great Lakes and marine systems, (iii) review the factors driving recruitment in Great Lakes fish, and (iv) compare factors driving recruitment in Great Lakes fish to factors driving recruitment in Baltic Sea fish. Based on comparisons of recruitment processes between marine and Great Lakes systems, we recommend areas for continued research on the early life stages of fish in the Great Lakes, including determining the effects of climate change and invasive species on recruitment. Biological similarities and differences between Great Lakes and marine species Fish display tremendous variation in life history strategies (Winemiller and Rose, 1992; Winemiller, 2005); however, some differences can be generalized for Great Lakes and marine species. Many of the large-bodied Great Lakes fish are among the most fecund North American freshwater fish (Frimpong and Angermeier, 2009). For example, walleye (Sander vitreus), burbot (Lota lota), and white bass (Morone chrysops) can all have greater than 500 000 eggs per female. However, compared with morphologically similar marine species, such as Atlantic cod (Gadus morhua), walleye pollock (Gadus chalcogrammus), and striped bass (Morone saxatilis) (all species that can have over 1 million eggs per female), the largebodied Great Lakes species have comparatively low fecundity. We compared fecundity, length at hatch (...truncated)