Scientific Illustration

Fig 1 Skull of a Male Salmon

Fig 2 Skull of a Male Brook Trout

by BioDivLibrary on Flickr.

British and Irish Salmonidæ /.
London [etc.]Williams and Norgate,1887..
biodiversitylibrary.org/page/5615808

minaturalismo:

Salmon sketch, for the Natural histoy museum, Santiago, Chile. 2012

rhamphotheca:

Sakhalin taimen (Hucho perryi)

CRITICALLY ENDANGERED

… also called the Stringfish, Japanese huchen, or Ito, is a species of fish in the salmon family (family Salmonidae) of order Salmoniformes. Sakhalin taimen is one of largest, most ancient salmon species and primarily inhabitats the lower to middle reaches of lakes and rivers.

Fishes over 30 cm long are almost exclusively piscivores, while the young feed mostly on aquatic insects. Females typically lay between 2,000-10,000 eggs in the spring on the sandy or gravelly river bottom. The average specimen caught have weighed around 5 kg (11 lb).

The global population of Sakhalin taimen has dwindled in recent years for a variety of reasons. The loss of more than 50% of their original habitat due to agriculture, urbanization, and more recently oil and gas development, is a major factor. Other considerable pressures include bycatch in the commercial salmon fisheries of Russia and Japan, as well as illegal fishing practices in Russia. The fish are also prized as trophies by Japanese recreational anglers…

(read more: Wikipedia)              

(illustration from Notes on some figures of Japanese fish : taken from recent specimens by the artists of the U. S. Japan expedition, 1856, James Carson Brevoort)

rhamphotheca:

Why Sockeye Salmon Are in Trouble

by Emily Sohn

Every year, millions of adult salmon return from the ocean to their home streams, where they lay eggs and produce the next generation of fish. But far fewer sockeye salmon are making it back to their freshwater mating grounds compared to a few decades ago, and that’s seriously affecting population sizes of the species throughout the Northwest, from Alaska to Washington State.

The discovery suggests that changing ocean conditions may be making life harder for some groups of wild salmon — possibly by reducing their food supply or increasing populations of predators.

By zeroing in on what, exactly, is causing the widespread decline, researchers hope to help managers figure out what to do about the problem.

“We found that substantial reductions in productivity of over 50 percent have occurred in the last two decades in a wide geographical area,” said Randall Peterman, a fisheries scientist at Simon Fraser University in Burnaby, Canada. “We were quite stunned to see these results.”…

(read more: LiveScience)        

(images: T - Sockeye Salmon (Oncorhynchus nerka) by Timothy Knepp - USFWS; B - School of spawning Sockeye, by TheInterior)

rhamphotheca:

Seven species of salmonids:

Five Pacific salmon and two trout—inhabit the rivers and streams of the Pacific Northwest. (Their North American ranges are indicated.) Although these fish share certain fundamental characteristics, the differences among them are numerous, both in behavioral traits and in appearance, as is evident from this rendition of spawning males. As the authors explain, conservation efforts aimed at protecting salmon often overlook the importance of preserving this biodiversity and focus instead on boosting the total numbers of fish.

(via: Scientific American)      (artist: Emma Skurnick)

biomedicalephemera:

Salmo scouleri (now Oncorhynchus gorbuscha) -  The Pink Salmon

Sometimes known as the humpback salmon or humpie, due to the humped back that males develop during spawning season.

Like all salmon, clearly one of the top predators in its ecosystem. The pink salmon is the smallest and most abundant of their family, but is still imperiled within California (though they only exist as far south as Sacramento) and Washington. On the West Pacific (throughout the Siberian and part of the Korean coastline), within British Columbia, and in Alaskan populations, the species is stable.  

Fauna Boreali-Americana; or the zoology of the northern parts of British America.: containing descriptions of the objects of natural history collected on the late northern land expeditions, under the command of Sir John Franklin. Part 3: The Fish. John Richardson, 1836.

Humpback Salmon (Oncorhynchus gorbuscha) Breeding Male

n802_w1150 by BioDivLibrary on Flickr.

The Atlantic salmon (Salmo salar)

biomedicalephemera:

Development of Salmo salar, from egg to alevin

You can easily see the developing eye and neural tube here. An “alevin” is the initially hatched fish, when it’s still living off its yolk sac.

The Atlantic Salmon’s eggs incubate at different rates, depending on the temperature of the water. Assuming water at least 6-8 C, the incubation is 35-45 days to “eyed” (when the eyes are visible within the egg), 18-20 days from eyed to hatched alevins, and 14-21 days until the alevin has used up its yolk sac and is a free-feeding fry (juvenile fish). In total, it’s about 68-86 days in total from being laid to becoming true fry.

La Monde de la Mer. Alfred Fredol, 1866.