scholarly journals Applying the Krogh Principle to Find Shortcuts to Understanding Pacific Salmon Production

2016 ◽  
Vol 6 (1) ◽  
pp. 455-468
Author(s):  
Richard Beamish ◽  
Chrys-Ellen Neville
Keyword(s):  
Pacific Salmon ◽  
Salmon Production

Challenges for Diadromous Fishes in a Dynamic Global Environment

2009 ◽  
Keyword(s):  
Chinook Salmon ◽  
Large Scale ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Commercial Catch ◽  
Atmospheric Processes ◽  
Energy Transfers ◽  
Salmon Production ◽  
The Impact

<em>Abstract</em>.-Pacific salmon <em>Oncorhynchus </em>spp. catches are at historic high levels. It is significant that one of the world's major fisheries for a group of species that dominates the surface waters of the subarctic Pacific is actually very healthy. Natural trends in climate are now recognized to cause large fluctuations in Pacific salmon production, as shown in historical records of catch and recent changes probably have been affected by greenhouse gas induced climate changes. Pink salmon <em>O. gorbuscha </em>and chum salmon <em>O. keta </em>production and catch has increased in the past 30 years and may continue in a similar trend for for the next few decades. Coho salmon <em>O. kisutch </em>and Chinook salmon <em>O. tshawytscha </em>catches have been declining for several decades, particularly at the southern end of their range, and they may continue to decline. In the 1970s, hatcheries were considered to be a method of adding to the wild production of coho and Chinook salmon because the ocean capacity to produce these species was assumed to be underutilized. Large-scale changes in Pacific salmon abundances are linked to changes in large-scale atmospheric processes. These large-scale atmospheric processes are also linked to planetary energy transfers, and there is a decadal scale pattern to these relationships. Pacific salmon production in general is higher in decades of intense Aleutian lows than in periods of weak Aleutian lows. Key to understanding the impact of climate change on Pacific salmon is understanding how the Aleutian low will change. Chinook and coho salmon are minor species in the total commercial catch, but important socially and economically in North America. A wise use of hatcheries may be needed to maintain abundances of these species in future decades.

Anatomical specialization in the gut of Pacific salmon (Oncorhynchus): evidence for oceanic limits to salmon production?

1997 ◽  
Vol 75 (6) ◽  
pp. 936-942 ◽  
Author(s):  
D. W. Welch
Keyword(s):  
Carrying Capacity ◽  
Chum Salmon ◽  
Pacific Salmon ◽  
Gelatinous Zooplankton ◽  
Oncorhynchus Keta ◽  
Evolutionary Selection ◽  
The North ◽  
Salmon Production ◽  
The North Pacific ◽  
Trophic Competition

The stomach (but not the intestine) of chum salmon (Oncorhynchus keta) is greatly enlarged relative to that of other species of Pacific salmon. This permits the exploitation of gelatinous zooplankton (jellyfish, ctenophores, and salps), an abundant but low-energy prey unused by other species of salmon, as a major food source. The unique gut structure of chum salmon therefore allows efficient feeding on a little-exploited branch of the food web and reduces interspecific trophic competition. The development of this remarkable anatomical specialization suggests that salmon abundances were previously high enough that the resulting trophic competition led to evolutionary selection to reduce trophic competition. As total salmon abundances in the North Pacific are now probably the highest of this century, the carrying capacity of the ocean rather than that of fresh water could limit overall salmon production if abundances are once again approaching pre-exploitation levels.

scholarly journals Forecasting Pacific Salmon Production in a Changing Climate: A Review of the 2011–2015 NPAFC Science Plan

2016 ◽  
Vol 6 (1) ◽  
pp. 501-534
Author(s):  
Shigehiko Urawa ◽  
James Irvine ◽  
Ju Kyoung Kim ◽  
Eric Volk ◽  
Alexander Zavolokin ◽  
...  
Keyword(s):  
Pacific Salmon ◽  
Changing Climate ◽  
Salmon Production

scholarly journals Forecasting Pacific Salmon Production in a Changing Climate: A Review of the 2011–2015 NPAFC Science Plan

2016 ◽  
Vol 6 (1) ◽  
pp. 501-534 ◽  
Author(s):  
Shigehiko Urawa ◽  
James Irvine ◽  
Ju Kyoung Kim ◽  
Eric Volk ◽  
Alexander Zavolokin ◽  
...  
Keyword(s):  
Pacific Salmon ◽  
Changing Climate ◽  
Salmon Production

Nutrients in Salmonid Ecosystems: Sustaining Production and Biodiversity

2003 ◽  
Keyword(s):  
Coho Salmon ◽  
Pacific Salmon ◽  
Positive Effects ◽  
Delivery Vector ◽  
Salmon Population ◽  
Population Sizes ◽  
Salmon Production ◽  
Salmon Carcass ◽  
Salmon Carcasses

<em>Abstract.</em>—A number of Pacific salmon populations have already been lost and many others throughout the range are in various states of decline. Recent research has documented that Pacific salmon carcasses serve as a key delivery vector of marine-derived nutrients into the freshwater portions of their ecosystems. This nutrient supply plays a critical biological feedback role in salmon sustainability by supporting juvenile salmon production. We first demonstrate how nutrient feedback potential to juvenile production may be unaccounted for in spawner-recruit models of populations under long-term exploitation. We then present a heuristic, life history-based, spreadsheet survival model that incorporates salmon carcass-driven nutrient feedback to the freshwater components of the salmon ecosystem. The productivity of a hypothetical coho salmon population was simulated using rates from the literature for survival from spawner to egg, egg to fry, fry to smolt, and smolt to adult. The effects of climate variation and nutrient feedback on survival were incorporated, as were density-dependent effects of the numbers of spawners and fry on freshwater survival of eggs and juveniles. The unexploited equilibrium population was subjected to 100 years of 20, 40, 60, and 80% harvest. Each harvest scenario greater than 20% brought the population to a reduced steady state, regardless of generous compensatory survival at low population sizes. Increasing harvest reduced the positive effects of nutrient contributions to population growth. Salmon researchers should further explore this modeling approach for establishing escapement goals. Given the importance of nutrient feedback, managers should strive for generous escapements that support nutrient rebuilding, as well as egg deposition, to ensure strong future salmon production.

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