Dating salmon postcards Ontario adult chat
Add to that the nails which tell wood, treament, and other information, and toss in all date nails used in poles and other timbers, and the total number of different nails from this continent easily exceeds 3,500. When North American railroads began to experiment with treated ties in the second half of the 1800s, it was not known which chemicals, treament methods, or woods were most economical.They needed some method of keeping track of the lives of ties, so like their European counterparts, they decided to mark them. By the late 1800s American railroads settled on the use of date nails.Over that time, most adult populations have become smaller, up to 10 percent shorter in length, researchers found.The data also showed that the largest Chinook salmon – fish that can weigh almost as much as a person – were once commonplace but are now rare or nonexistent.
Although the study didn’t formally test why the largest Chinook salmon are disappearing, the authors – after considering other possibilities, such as climate change and competition between different species of salmon – believe growing populations of resident orcas in the salmon’s northern feeding ground are the most plausible cause.While efforts, such as dam removals, are underway to save threatened runs, some researchers have predicted that global warming and habitat loss will all but eradicate North American salmon south of Canada.So it may be no coincidence that southern resident killer whales – a distinct population from the northern resident whales that live off the coasts of Oregon, Washington and British Columbia – have dwindled to just several dozen animals and are listed as endangered.Authors of the , published in the journal Fish and Fisheries, suggest that increasing populations of northern resident orcas, or killer whales, are selectively eating the largest of the Chinook salmon, contributing to the fish’s shrinking average size.
million Chinook salmon dating back 40 years, from the waters off California to Alaska.Often, salmon fishers – both commercial and recreational – have been blamed.