Great Lakes Salmon Research Articles

Ecological consequences of Great Lakes salmon subsidies for stream-resident brook and brown trout

Introduced Pacific salmon (Oncorhynchus spp.) deliver novel, pulsed resource subsidies to Great Lakes streams. We explored interactions between native brook trout (Salvelinus fontinalis) and non-native brown trout (Salmo trutta) in the context of this resource pulse. Diets surveyed before and during salmon spawning showed that, regardless of species, trout consumed 4.5-fold more biomass during than before salmon runs. Brook trout grew more quickly than brown trout under controlled feeding regimes due, in part, to their higher food conversion efficiency of 36% compared with 21%. Bioenergetics model simulations explored the influence of temperature on the exploitation of resource pulses and found 35% lower growth rates and increased gorging at colder temperatures. Overall, we found evidence that brook trout and brown trout foraging and growth are modulated by the salmon resource pulse, especially through gorging on eggs. However, these species exhibit distinct physiological adaptations and environmental preferences that may influence their ultimate capacity to exploit resource pulses. The effects of environmental conditions and salmon subsidies on stream-resident trout have broader consequences for fisheries management and conservation efforts.

The geometry of reaction norms yields insights on classical fitness functions for Great Lakes salmon.

Life history theory examines how characteristics of organisms, such as age and size at maturity, may vary through natural selection as evolutionary responses that optimize fitness. Here we ask how predictions of age and size at maturity differ for the three classical fitness functions–intrinsic rate of natural increase r, net reproductive rate R0, and reproductive value Vx−for semelparous species. We show that different choices of fitness functions can lead to very different predictions of species behavior. In one’s efforts to understand an organism’s behavior and to develop effective conservation and management policies, the choice of fitness function matters. The central ingredient of our approach is the maturation reaction norm (MRN), which describes how optimal age and size at maturation vary with growth rate or mortality rate. We develop a practical geometric construction of MRNs that allows us to include different growth functions (linear growth and nonlinear von Bertalanffy growth in length) and develop two-dimensional MRNs useful for quantifying growth-mortality trade-offs. We relate our approach to Beverton-Holt life history invariants and to the Stearns-Koella categorization of MRNs. We conclude with a detailed discussion of life history parameters for Great Lakes Chinook Salmon and demonstrate that age and size at maturity are consistent with predictions using R0 (but not r or Vx) as the underlying fitness function.

Something Spectacular: My Great Lakes Salmon Story by Howard A. Tanner

Book Reviews 151 Howard A. Tanner. Something Spectacular: My Great Lakes Salmon Story. East Lansing: Michigan State University Press, 2019. Pp. 268. Illustrations. Index. Notes. Cloth: $39.95. When I was approximately ten years old, my parents treated me to a visit to Cedar Point, the Ohio-based amusement park on the shores of Lake Erie. I recall the menu at one of the park’s eateries offering a special fish plate—I believe it was walleye. The listing in the menu included a brief but cryptic warning about overindulging in fish from the Great Lakes due to contamination. The warning reflected the public tenor of the 1970s and early 1980s in many lakeside communities, a recognition that the Great Lakes were a polluted, embattled resource. In his new book, Something Spectacular: My Great Lakes Salmon Story, Howard A. Tanner briefly discusses the concerns he and other colleagues shared regarding the persistence of DDT-derived pesticides in the lakes and the threat those derivatives posed to the economic viability of the new salmon sport fishery. While not the focus of his work, the historical changes connected to the introduction of Pacific salmon are just as important. Something Spectacular is as much memoir as historical study, written from the perspective of the person at the center of Pacific salmon introductions into the Great Lakes system. Tanner’s work is written from a perspective reflected in its title, that the recreational fishery and the managerial changes that sanctioned and followed the first salmon introductions were almost entirely positive. If viewed through an anthropocentric and economic lens, one could make a strong case in that regard. Included with his central narrative are Tanner’s connected recollections of his long professional life working in fisheries science and management, his vivid memories regarding service in World War II, and everyday shared experiences and professional work alongside his wife, Helen. With enduring and serious questions regarding the logic of humanintroduced exotic species into the ecologically embattled Great Lakes, an important consideration is that at least equally “spectacular” stories exist in the historical subplots and residual changes influenced or brought about through the audacious efforts of Tanner and his colleagues. The fishery’s stimulus on the banning of DDT in Michigan and subsequent reductions in Great Lakes fish toxicology are one example. There are others. That the fishery enforcement efforts of Michigan’s Department of Natural Resources and its allies led (to Tanner’s continued dismay) to the courts’ woefully belated recognition and legal protection of the treatyguaranteed rights of the sovereign Great Lakes Indian Nations was 152 The Michigan Historical Review another arguably “spectacular” outcome. In that case and others, readers will need to turn to other works, such as Robert Doherty’s Disputed Waters: Native Americans and the Great Lakes Fishery, for a more complete picture. Other tangential developments are important considerations when examining this story as a whole. With the continued and evolving dialogue regarding intentional human introductions of exotic species into existent ecosystems, Something Spectacular recounts what was perhaps the most significant introductions attempted in the Great Lakes, written from the perspective of the fishery scientist at its center. This is an important and accessibly written work. It is especially recommended for anyone interested in the Great Lakes, water research, fisheries, or the introduction of exotic species. Kent LaCombe University of California, Riverside Brian C. Wilson. John E. Fetzer and the Quest for the New Age. Detroit: Wayne State University Press, 2018. Pp. 326. Bibliography. Illustrations. Index. Notes. Cloth: $34.99. Many Michiganders are aware of John E. Fetzer’s life as a broadcaster and pioneer in local radio (he founded WKZO), as a businessman and philanthropist (he made the Forbes list of 400 wealthiest people in America), and as owner of the Detroit Tigers (with whom he won the World Series in 1968), but few are aware of his lifelong eclectic religious journey. This book is not a biography in the usual sense but instead probes the soul of a man who believed the world is bigger, and could potentially be better, than any one faith tradition imagines. Forward-thinking in his professional life, Fetzer was even more progressive in his private...

Are PCBs the Major Neurotoxicant in Great Lakes Salmon?

Epidemiological studies have demonstrated an association between consumption, by women, of contaminated Great Lakes salmon and deficits in cognitive performance in the children of these women. Although significant statistical associations between polychlorinated biphenyl (PCB) body burdens and these negative outcomes suggest that PCBs may be responsible, the fetus and neonate are also exposed to other fish-borne neurotoxicants. In this manuscript we present data from two developmental studies that support the hypothesis that PCBs may serve either as a marker for other contaminants that are responsible for the observed effects, or that other contaminants present in the fish interact synergistically with the PCBs to produce the observed neurotoxicity. In the first study we demonstrated that exposure of rats to diets containing lyophilized Great Lakes salmon, resulting in exposure to as little as 13.9 μg/(kg·day) of total PCBs, induced significant reductions in regional brain dopamine (DA) concentrations. In the second study, we demonstrated that exposure of rats to the ortho-substituted PCB congener (2,4,2′,4′-tetrachloro- biphenyl) at 1, 10 or 20 mg/(kg·day) also induced significant reductions in DA concentrations in the same brain regions although only at the two highest doses—levels at least 100-fold higher than seen in the first study. On the basis of these developmental neurochemical studies we suggest that the reported cognitive deficits in children exposedin uteroand during lactation to fish-borne contaminants may be due either to contaminants other than PCBs or to complex interactions between PCBs and other neurotoxicants present in the fish.

PCB Congener Patterns in Rats Consuming Diets Containing Great Lakes Salmon: Analysis of Fish, Diets, and Adipose Tissue

As part of a multidisciplinary toxicological investigation into Great Lakes contaminants, chinook salmon were collected from Lake Huron (LH) and Lake Ontario (LO) and incorporated (as lyophilized fillets) into standard rat diets as 20 or 100% of the protein complement (5 or 20%, w/w diet—LH5, LH20, LO5, and LO20 diets). Final PCB concentrations in the experiment ranged from 3.15 ng/g in the control diet to 1080 ng/g in the high-dose (20%) LO diet, with maximal estimated daily consumption by the rats of 82μg PCBs/kg body wt in the LO20 dietary group. Seventeen PCB congeners, PCB 85, 99, 101, 105, 110, 118, 128, 129, 132, 138, 149, 153, 170, 177, 180, 187, and 199, occurred at ≥3.0% of the total PCBs in the fish with no major site differences. Cumulatively, these 17 congeners accounted for up to 75% of the total PCBs in the fish compared to 44 and 54% in two commercial Aroclors, 1254 and 1260, respectively. PCB 77 was the major “dioxin-like” congener in the fish, followed by PCB 126 and then PCB 169. All major dietary congeners bioaccumulated in the adipose tissue of the rats with the exception of PCB congeners 101, 110, 132, and 149. The group of 17 major congeners accounted for up to 71% of the total PCBs in adipose tissue samples collected from the rats following up to 19 weeks of diet ingestion. Of the coplanar PCB congeners, PCB 77 appeared to bioaccumulate to a lesser extent compared to PCBs 126 and 169. When comparing PCBs in the rat adipose tissue to PCB congeners in Canadian breast milk, PCBs 44, 49, 74, and 137 tended to occur in higher amounts in the human samples (contributing together 18.4 vs. 1.4% of the total PCB concentration), whereas PCB 129 occurred at higher levels in the rats (3.4 vs. 0.3% of the total PCB concentration, respectively). Although adipose tissue from the rats fed diets containing Great Lakes salmon had up to two orders of magnitude higher concentrations of PCBs compared to average human values, with the exception of some lower chlorinated congeners, similar major congeners tended to be present in both the rats in the present study and humans.

Neurochemical Effects of Consumption of Great Lakes Salmon by Rats

This study, part of a larger project to determine the health consequences of both perinatal and adult exposure to contaminated salmon from the Great Lakes, determined the neurochemical effects of exposure of rats to chow adulterated with lyophilized salmon fillets. Concentrations of biogenic amines, their metabolites, and choline acetyltransferase (ChAT) were determined in the frontal cortex (FC), nucleus accumbens, caudate nucleus (CN), hippocampus (HC), and substantia nigra (SN) of adult rats who had been exposed, both perinatally and as adults, to standard rat chow adulterated with either 5 or 20% (w/w) lyophilized fillets from either Lake Huron (LH) or Lake Ontario (LO) salmon. Dopamine (DA) concentrations in the FC were significantly decreased following exposure to both 20% fish diets. CN DA concentrations were significantly reduced in rats exposed to all diets, while SN DA was decreased only in the LO20-fed animals. SN norepinephrine concentrations were reduced in all groups except for the LO5-fed rats. 3,4-Dihydroxyphenylacetic acid (DOPAC) concentrations in the FC were significantly increased in the LH20 and LO5 groups, while CN DOPAC concentrations were reduced in LH20, LO5, and LO20 animals. 5-Hydroxyindoleacetic acid concentrations were reduced in the FC and CN of all animals exposed to diets adulterated with Great Lakes salmon. ChAT concentrations were unaffected in rats exposed to any of the adulterated diets. The significant reductions in DA, particularly in the FC and CN, suggest that either fish-borne contaminants or consumption of fish, per se, may affect behaviors that require inhibition of normal responding. We conclude that consumption of contaminated fish from the Great Lakes may result in sufficient reductions in biogenic amine function to result in significant deficits in important behavioral functions in the rat and, by inference, in the perinatally exposed human.

A Multigeneration Study to Ascertain the Toxicological Effects of Great Lakes Salmon Fed to Rats: Study Overview and Design

Fish from the Great Lakes can be contaminated with a plethora of industrial, agricultural, and environmental chemicals. These chemicals have been associated with reproductive and other toxicological effects in fish and fish-eating birds found in the Great Lakes basin. To obtain more insight into this association, several laboratory studies have been undertaken wherein fish have been incorporated into the experimental diets to determine the effect of their ingestion upon the test animals. In addition, several human epidemiological studies have found correlations between Great Lakes fish consumption and effects in neonates which have been attributed to polychlorinated biphenyls without any appreciable consideration as to what synergistic or antagonistic effects other chemicals or heavy metals may or may not have contributed to the observed findings. Herein is presented the design of a two-generation feeding–reproduction study that incorporated lyophilized chinook salmon (Oncorhynchus tsawytscha) fillets into the diets of Sprague–Dawley rats. The findings of this study will be presented in the sections which follow.

Dietary and Tissue Residue Analysis and Contaminant Intake Estimations in Rats Consuming Diets Composed of Great Lakes Salmon: A Multigeneration Study

To further characterize the toxicological risk associated with chemical contaminants in Great Lakes fish, a multigeneration rat reproduction study was designed. Mature chinook salmon (Oncorhynchus tsawytscha), collected during the Fall 1991 spawning runs from Sydenham River, Lake Huron, and Credit River, Lake Ontario, were filleted, lyophilized, and incorporated into standard rat diets at 25% (w/w) or 100% (w/w) of the normal protein compliment [casein, 20% (w/w)]. This resulted in diets composed of 5 or 20% (w/w) lyophilized fish and estimated daily fish intakes by the rats at levels approximately 15- and 60-fold greater, respectively, than the current estimate for the Canadian public for all fish and seafood. Both fresh and lyophilized fish were analyzed for the following groups of contaminants: halogenated aromatic hydrocarbons [polychlorinated biphenyls, dibenzodioxins, and dibenzofurans (PCBs, PCDDs, PCDFs)], polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, metals, volatile organics, and other extractable organics (chlorinated phenols and benzenes). In general, only minor site differences existed for the specific types of contaminants detected; however, fish from the Credit River contained slightly greater amounts of PCBs (2- to 3-fold), dioxin toxic equivalencies (TCDD TEQs; 1.5- to 2.0-fold), DDT and metabolites (1.5-fold), and appreciably higher amounts of mirex (15-fold). This general pattern of contaminant differences continued when the various diets were prepared using the lyophilized fish. Tissue samples (adipose, liver) were taken from the animals at various stages of the study and also analyzed for the same groups of contaminants. In general, adipose tissue was the major reservoir for organochlorine (OC) pesticides and PCBs, while “dioxin-like” PCDD/DF congeners and mercury were found preferentially in the liver. Contaminant intake calculations and tissue residue levels are provided.

Influence of Maturity on the Volatile Aroma Compounds from Fresh Pacific and Great Lakes Salmon

ABSTRACTVolatile aroma compounds from freshly harvested prime and spawning‐condition salmon (Oncorhynchus sp.) from the Pacific Ocean (chi‐nook, sockeye, chum, coho and pink) and the Great Lakes (chinook, coho and pink) were quantitatively measured. Both prime and spawning‐condition salmon had 1‐octen‐3‐one, 1,5‐octadien‐3‐one, 1‐octen‐3‐ol, 1,5‐octadien‐3‐ol, 2‐octen‐1‐ol, and 2,5‐octadien‐1‐ol which contributed distinct and characteristic plant‐like aromas to the fish. More pronounced aromas of spawning‐conditions almon were attributed to greater concentrations of the 8‐carbon compounds in combination with occurrence of (E)‐2‐nonenal, (E)‐2,(Z)‐6‐nonadienal, 6‐nonen‐1‐ol, and 3,6‐nonadien‐1‐ol which added sweet, cucumber‐ or melon‐like aroma notes. The 9‐carbon compounds may have resulted from biochemical regulation of physiologically active lipid‐derived substances which activate mucus secretion in salmon approaching sexual maturity.

Dietary consumption of Great Lakes salmon: Public Health perspectives

Dietary consumption of Great Lakes salmon: Public Health perspectives

Contamination of Stream Fishes with Chlorinated Hydrocarbons from Eggs of Great Lakes Salmon

Abstract Pacific salmon Oncorhynchus spp. have been stocked in the Great Lakes where they accumulate body burdens of chlorinated hydrocarbons. The transport of these contaminants to resident communities in spawning streams was studied in two tributaries of Lake Michigan accessible to anadromous spawners and one control tributary blocked to them. No polychlorinated biphenyls (PCBs), DDT, or dieldrin were detected in the sediments or biota of the control stream, or in sediments of the test streams. However, trout Salmo spp. and, to a lesser extent, sculpins Cottus spp. accumulated PCBs and DDT as a result of eating contaminated salmon eggs. Eggs constituted as much as 87% (by weight) of the total stomach contents of trout collected during the salmon spawning season early October to early January. Salmon eggs contained 0.46–9.50 mg PCBs/kg, and 0.14–1.80 mg DDT/kg. Consumption of eggs varied greatly among individual trout, and there was a strong correlation between numbers of eggs in the stomachs and PCB and...

Hormonal control of gonadal maturation and development of secondary sexual characteristics in coho salmon, Oncorhynchus kisutch, from Lakes Ontario, Erie, and Michigan

Pituitary and serum gonadotropin (GTH) levels and plasma 11-ketotestosterone levels were measured in sexually mature spawning adult and sexually precocious “jack” coho salmon ( Oncorhynchus kisutch) from Lakes Ontario, Michigan, and Erie to determine whether the relatively low fecundity of the Lake Erie coho salmon has an endocrine aetiology, possibly associated with the apparent thyroid dysfunction in the Great Lakes salmon. Highest pituitary GTH content was found in Lake Ontario adult males and females; pituitary GTH content of coho salmon from Lakes Erie and Michigan were similar. Serum GTH levels were similar in adults and “jacks” from Lakes Ontario and Michigan and these were significantly higher than in the Lake Erie fish. Serum 11-ketotestosterone levels in adult males and “jacks” from Lake Ontario were up to 5.4-fold higher than in comparable animals from Lakes Erie and Michigan, whereas in the females serum 11-ketotestosterone levels in the Lake Erie coho salmon were significantly lower than in comparable fish from the other two lakes. The findings are discussed in relation to the interlake differences in gonadosomatic index, egg fecundity, and degree of apparent thyroid dysfunction.

Thyroid responses in rats fed diets formulated with Great Lakes coho salmon.

In earlier papers we reported thyroid hyperplasia and goiters together with clinical signs of hypothyroidism in male rats fed diets of Great Lakes coho salmon (OncorhYnchus kisutch) (SONSTEGARD & LEATHERLAND 1979a, LEATHERLAND & SONSTEGARD 1980). In these preliminary studies, the rats were fed a total fish diet without supplementation of any kind. The present paper reports on the effects of Great Lakes coho salmon on thyroid function in rats when the fish was given as part of a formulated diet together with rat chow, vitamin, mineral, and lipid supplementation. The study is a further attempt to assess the possible health hazards of using Great Lakes salmon for human consumption and an attempt to monitor the level of goitrogenic xenobiotics in the flesh of these fish.

Structure of thyroid and adrenal glands in rats fed diets of Great Lakes coho salmon ( Oncorhynchus kisutch)

Feral Great Lakes coho salmon ( Oncorhynchus kisutch) were fed to Sprague-Dawley rats in order to determine the effects of bioaccumulated xenobiotics on mammalian endocrine physiology and assess the risk of human consumption of Great Lakes salmon. Rats fed coho salmon from Lakes Ontario, Erie, and Michigan had enlarged thyroid glands compared with controls fed Pacific Ocean coho or Rat Chow. The thyroid epithelial cell height was significantly increased in the rats fed Lake Ontario coho for 8 weeks, and the cells in this group, and to a lesser extent in the group fed Lake Michigan coho, contained more mitochondria, rough endoplasmic reticulum, Golgi profiles, and colloid-filled vacuoles than those of controls or rats fed Lake Erie coho. Dietary iodide supplementation to rats fed the Lake Ontario coho diet had no effect on either thyroid weight or thyroid histology, suggesting that the goiter was not due to iodide deficiency. The adrenal glands of rats fed coho from Lakes Erie or Michigan were significantly larger ( P < 0.01) than those in all other groups, apparently because of an enlargement of the zonae fasciculata and reticularis. In addition, rats given the Lake Ontario coho diet had markedly dilated sinusoidal spaces in the zonae fasciculata and reticularis of the adrenal cortex and also in the adrenal medulla.

Are goiter frequencies in Great Lakes salmon correlated with organochlorine residues?

Are goiter frequencies in Great Lakes salmon correlated with organochlorine residues?

Fecundity of Coho Salmon (Oncorhynchus kisutch) from the Great Lakes and a Comparison with Ocean Salmon

I measured fecundity of coho salmon (Oncorhynchus kisutch) that matured in the Great Lakes to make comparisons with Pacific Ocean coho salmon and among groups of Great Lakes salmon. Numbers of eggs produced (1600–3500) by Great Lakes salmon were comparable to production (1500–3300) by Pacific salmon of similar size. Average egg diameters of Lake Michigan (7.1–7.4 mm) and Pacific salmon (6.1–7.4 mm) were also comparable but Lake Superior eggs were smaller (5.1–5.4 mm). Fecundity of second generation freshwater salmon which originated from Lake Michigan eggs was similar to that of the first generation which originated from Pacific eggs because the average numbers (2938–3243) and diameters (7.1–7.4 mm) of eggs produced were about the same. On the average, Lake Michigan salmon contained more (2938) and larger (7.1-mm diam) eggs than did Lake Superior salmon (2150 and 5.1-mm diam) of the same year-class and early life history.

Thyroid Activity in Coho Salmon from Oregon and Lake Michigan

Blood and thyroid tissue samples were compared among adult, jack, and smolt coho salmon from Oregon and Lake Michigan. Blood samples were analyzed for thyroxine and triiodothyronine, and thyroid tissue was examined histologically. Significant differences in estimates of thyroxine and triiodothyronine levels and histological condition indicated that Lake Michigan jack and adult coho salmon were hypothyroid. The authors theorize that the hypothyroid condition is related to the general iodine deficiency in the Great Lakes Region, contributes to the lower fertility and fecundity of the Great Lakes salmon, and exaggerates pesticide accumulation in the fish.