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. 

Polar bears, like other large predators, are hard to track and count, and available data is often fragmentary and difficult to piece together. Now, a new model provides estimates for key parameters for polar bears in the Chukchi Sea off north-western Alaska, by combining available data from telemetry, marking and recapturing, and counts. The model estimates that 83% of females give birth every year, that litter sizes are 2.11 per year, and that survival is about 90% for both males and females. 

Individual fishing quotas have been introduced to the Pacific whiting fishery off the US west coast, involving allocating rights to fish quota to both harvesters (80%) and processors (20%) and letting individuals decide when and how to to catch and land fish. A unique dataset of prices and costs allowed researchers to examine the impact of this change on land-based processors. 

Scientific surveys using fishing rods, each fishing multiple hooks, have the advantage of being able to access rocky areas while obtaining samples of fish for length and age estimation. However, in areas with lots of fish, it is possible for nearly every hook to catch a fish, resulting in an upper limit on the number of fish that can be counted. 

Fisheries management is often seen as a balancing act that aims for economic development, environmental protection and social development. Previous work shows that overfishing or other forms of poor ecological health, reduces economic profits; and it has long been assumed that pursuit of profits leads to poor social outcomes for fishing communities. But now a new analysis of 121 fisheries worldwide suggests this second assumption may not hold, based on scores of 68 different ecological, economic, and social metrics for each fishery. 

Oceanic discoveries of new species continue at pace, with a new species added to the 34,000 previously described: the Polkadot Dwarfgoby (Eviota maculosa). The new species occurs in New Guinea, Indonesia, and Pohnpei in the Federated States of Micronesia, and is distinguished by unique fin patterns, distinctive genetics, and multiple rows of trident-like teeth in both the upper and lower jaws. 

Forage fish are small, densely schooling fish at the heart of many marine ecosystems. These fish, including sardines, anchovies, menhaden and their kin, consume tremendous quantities of plankton and also provide abundant food for top marine predators such as larger fish and whales. A key characteristic of these species is their dramatic fluctuation in numbers between high “bonanza” periods and low “collapse” periods, which make them hard to manage. 

Tom Quinn and colleagues have found that two decades of carcasses — nearly 600,000 pounds of fish — tossed to the left side of Hansen Creek did have a noticeable effect: White spruce trees on that side of the stream grew faster than their counterparts on the other side.

Captive breeding programs are intended to rebuild highly endangered populations, but a major problem is how to reintroduce captive-bred individuals back to their native habitat. Often, there is low survival of reintroduced individuals compared to wild-born individuals. Such is the case for the critically endangered Vancouver Island marmot, which had shrunk to just 30 individuals in 2003. A new experiment compares survival to breeding age for three strategies: transferring wild-born individuals, translocating captive-born individuals to wild habitat, and a new stepping stone strategy that involved first transplanting captive born individuals to a safe wild area with high survival before transferring them in their second year to the lower-survival final destination.