The Pacific Lamprey Entosphenus tridentatus, an anadromous fish native to the northern Pacific Ocean and bordering freshwater habitats, has recently experienced steep declines in abundance and range contractions along the West Coast of North America. During the early 1990s, Native American tribes recognized the declining numbers of lamprey and championed their importance. In 2012, 26 entities signed a conservation agreement to coordinate and implement restoration and research for Pacific Lamprey. Regional plans have identified numerous threats, monitoring needs, and strategies to conserve and restore Pacific Lamprey during their freshwater life stages. Prime among these are needs to improve lamprey passage, restore freshwater habitats, educate stakeholders, and implement lamprey‐specific research and management protocols. Key unknowns include range‐wide trends in status, population dynamics, population delineation, limiting factors, and marine influences. We synthesize these key unknowns, with a focus on the freshwater life stages of lamprey in the Columbia River basin.
Six blastomere morphology parameters indicative of cell development abnormalities, egg diameter, dry weight, total lipid, lipid classes and fatty acids were determined for egg batches collected daily from three Atlantic cod (Gadus morhua) broodstock groups over the course of one spawning season. Egg batches were incubated to hatch and each morphological and biochemical parameter was tested as a predictor of hatching success. Five of the six blastomere morphology parameters were significantly positively correlated with each other. Correlation coefficients among several fatty acid parameters were also significant but correlation coefficients among the various lipid classes were mostly not significant. No significant correlations were found between blastomere morphology and lipid class or fatty acid parameters. Egg dry weight was negatively correlated with cell clarity, %docosahexanoic acid (DHA), DHA:eicosapentaenoic acid, and Σ polyunsaturated fatty acids. Fertilization success was not significantly correlated with any of the morphology or biochemistry parameters. Within‐population variability in several morphological and fatty acid parameters was related to elapsed time since onset of first spawning. However, the occurrence of such relationships with elapsed time was highly variable and inconsistent among the three broodstocks, typically being significant for only one or two broodstocks but not all three. Mean hatching success rates were high (>75%) in all three broodstocks but hatching success was not significantly related to any of the morphological or biochemical parameters nor to elapsed time from onset of first spawning. The implications of these results are discussed in terms of the utility of the various morphology and biochemistry parameters as measures of egg quality in marine finfish hatcheries.
During a study of the early marine survival of Chinook Salmon Oncorhynchus tshawytscha and Coho Salmon O. kisutch in the Strait of Georgia from 1998 to 2010, moderate abundances of juvenile Sockeye Salmon O. nerka were observed to remain in the strait much longer than previously thought. In 2008, DNA stock identification showed that these juveniles were from the Harrison River, a population with a sea-type life history in which juveniles enter the ocean during the year of emergence from the gravel. Using information collected in 1998-2010, we describe the early ocean life and production of Harrison River sea-type Sockeye Salmon. Juveniles entered the Strait of Georgia from the Fraser River over an extended period, with most entering after mid-July-about 8 weeks later than lake-type juveniles, which had virtually all left the strait by that time. The September diets of sea-type juveniles were highly selective for hyperiid amphipods, which were not abundant in the zooplankton.
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