Retrospective growth analysis of Atlantic salmon (Salmo salar) from the Miramichi River, Canada

Abstract

We have developed a multidecadal retrospective growth history for the principal sea-age groups of the Miramichi River population of Atlantic salmon ( Salmo salar ) that characterizes freshwater growth and marine growth partitioned on a number of different time scales. Based on precedent with European salmon, we tested whether postsmolt growth was positively correlated with recruitment, assuming that growth during the postsmolt year mediates predation mortality. We found no such correlation in the Miramichi postsmolt growth pattern and instead found evidence of a negative correlation between growth and recruitment established by the second month that the fish were at sea. This negative correlation was interpreted as a density-dependant response of the population to recruitment determined early in the marine phase. There was inconsistent evidence that smolt size, as represented by freshwater zone length of the scale, influenced the pattern of recruitment. Finally, we found systematic differences between one-sea-winter (1SW) and 2SW returns related to greater postsmolt growth and, in particular, greater winter growth experienced by fish maturing after the first sea-winter. These data are consistent with findings relating climate variability during the months after smolts migrate to sea and recruitment variability, suggesting that the mortality is a short-duration event independent of growth conditions.

Variation in wind and piscivorous predator fields affecting the survival of Atlantic salmon, Salmo salar, in the Gulf of Maine

“…The proposed recruitment mechanism draws on a phenological mismatch between thermal conditions in fresh water and the ocean that delivers post‐smolts into warmer ocean conditions with a more aggressive predator field. This mechanism has been proposed for stocks in the Gulf of St Lawrence, which represent trends in the stock complex (Friedland et al. 2003b, 2009b), and specifically for stocks in the GOM (Friedland et al.…”

“…The evidence from wild populations comes from river systems in both Canada and the United States including: the Margaree stock from Nova Scotia (Friedland et al. 2005); the Machias and the Narraguagus rivers of coastal Maine (Hogan & Friedland 2010); and the Miramichi River, the largest salmon‐producing river in North America (Friedland et al. 2009b).…”

Lake Ontario salmon (Salmo salar) were not migratory: A long-standing historical debate solved through stable isotope analysis

“…Comparative data from modern Atlantic Salmon scales2930 as well as European505152 and North American53 archaeological bones were sourced from previously published studies and are supplemented by new analyses of a single European Atlantic Salmon individual from an Early Christian context from the site of Knowth in Ireland. Morphological analyses of scales from 5 of the 7 nineteenth-century Atlantic Salmon skin mounts were used to provide a second line of evidence for salmon origin and were conducted at the National Marine Fisheries Service (Narragansett, RI, USA) using established methods5455 (Supplementary Information). …”

Synchrony in marine growth among Atlantic salmon (Salmo salar) populations

“…The reasons for this difference in growth rate are not clear, and exceptions exist (Friedland et al 2009a). In the west Atlantic, Saunders (1969) and Anderson (1985) suggested that grilse and MSW salmon have different migration routes at sea.…”