Snake River salmonids are federally protected, but face a succession of dams to navigate from the ocean to the spawning grounds. The final dam in the sequence is the Lower Granite Dam. Ascending salmonids (sockeye salmon, steelhead, and Chinook salmon) all enter the fish ladders on the side of the dam, but some pass straight through and exit above the dam, while others are shunted off to one side and either released after a longer pathway, or held in tanks and sampled before being released to continue up the fish ladders. 

The dry northern reaches of Earth contain nearly half of all of the carbon originating in living matter, mostly stored in the frozen soils of the permafrost. It has been long thought that warming in the Arctic will result in this carbon being released from the soil and activated again, through the many lakes that are prominent features of the Arctic. 

Shifting baselines is the concept that each human generation thinks “normal” conditions are those when they were growing up, and therefore only takes into account declines during their lifetime, instead of over multiple generations. A new paper now examines newspaper headlines over time to see whether declining fish size is detectable in fish described as superlatively enormous (e.g. “giant”, “huge”, or “monster”), finding declines in reports of lengths. 

This winter, Greg Jensen is releasing his follow-up book, Beneath Pacific Tides: Subtidal Invertebrates of the West Coast. Like the charismatic crustaceans featured in his debut publication, the colorful and bizarre invertebrates found along the Pacific Coast are explored in this new user-friendly guide, featuring Jensen’s underwater photography.

Male Pacific salmon usually compete aggressively with each other to gain access to spawning females, and are most successful when they are old and large. But a few males come back from the ocean early and small, and with less noticeable male traits. These small males are called “jacks” and cannot win battles of aggression but instead compete by sneaking into the spawning arena and fertilizing eggs on the sly. 

Genetic engineering is widely used in plants and animals to promote rapid growth and create resistance to common diseases. One genetic modification that has achieved prominence in fish is the insertion of growth hormone transgenes, which produce dramatically larger sizes and rapid growth rates. However, there is concern that escaped genetically modified fish might breed with their wild counterparts, passing on the genetic modification and changing the wild population. 

Long-term life-support in space requires renewable sources of oxygen and food that can survive and thrive in a closed system without any external inputs. In a closed-system experiment, three species of green algae were added to a nutrient mixture together with a grazer species, the common water flea (Daphnia magna). Despite calculations of the appropriate level of carbon and nitrogen needed in the mixture, the pH in the closed system rapidly increased to become highly alkaline (pH 10-11), so much so that most forms of life would not be able to survive. 

Managing fisheries usually follows one of three pathways: limiting catches, limiting fishing effort, or limiting where fishing can take place. In a new review, each of these pathways is explored to examine their biological, social and economic implications. Limiting catches includes guideline harvests, strict limits on the total catch, allocations to groups, division of the total catch among individual participants, and fully transferable individual rights to catch a portion of the total allowable catch. 

Water temperatures affect the length of salmon incubation, including the periods between spawning and hatching, and between hatching and the emergence of free-swimming fry. In Bristol Bay, Alaska, lake temperatures are predicted to increase by 0.7-1.4°C from 2015 to 2099 at the time of the year when incubation occurs, due to the effect of human emissions of greenhouse gases. As a result, sockeye salmon in Alaska will start hatching 16 to 30 days earlier than at present, according to a new model that examined the effects of climate change on 25 populations of sockeye salmon in four Alaskan lakes. 

Two new species of jawfishes (family Opistognathidae) have been described for the first time this month. These small fish have fascinating life histories, digging burrows in sandy bottoms near reefs, and relying on males to brood eggs in their mouths. Each burrow houses one fish, and they strongly defend their burrows. The first new species, Thionyi’s jawfish (Opistognathus thionyi), is found in Vitória-Trindade Chain and Fernando de Noronha Archipelago off Brazil; while the second new species, the Brazilian dusky jawfish (Opistognathus vicinus), is found off mainland Brazil.