Ocean Acidification and Ocean Warming Effects on Pacific Herring (Clupea pallasi) Early Life Stages

Increasing green house gas emissions are expected to raise surface seawater temperatures and lead to locally intensified ocean acidity in the U.S. Pacific Northwest. Pacific herring (Clupea pallasi) are ecologically and economically important forage fish species native to this region. While the impacts of ocean acidification and ocean warming on organism physiology have been extensively studied, less is known on how concurrent climate change stressors will affect marine fish. Therefore, our study focused on the combined effects of ocean acidification and warming on Pacific herring early life history stages. Pacific herring embryos were incubated under a factorial design of two temperature (10°C or 16°C) and two pCO2 (600 μatm or 1200 μatm) treatments from fertilization until hatch (6 to 15 days depending on temperature). Elevated pCO2 was associated with a small increase in embryo mortality. Elevated temperature, as a single stressor, generated greater embryo mortality and embryo heart rates, larger yolk areas upon hatch, lower hatching success, and shorter larval lengths; compared with the same parameters measured under ambient temperature. The interaction of elevated temperature and pCO2 was associated with greater embryo heart rates and yolk areas compared to ambient conditions. This study suggests that while temperature is the primary global change stressor affecting Pacific herring embryology, interaction effects with pCO2 could introduce additional physiological challenges.

Sighting rates and prey of Minke Whales (Balaenoptera acutorostrata) and other cetaceans off Cormorant Island, British Columbia

From June to August 2012, we conducted over 500 h of visual surveys from Cormorant Island, British Columbia, to determine behaviour and habitat use patterns of nearby cetaceans. Seven species were documented, but Minke Whales (Balaenoptera acutorostrata) were by far the most common and were observed lunge feeding at the surface on 15 occasions. In addition, this species was documented surface lunge feeding on Pacific Herring (Clupea pallasi) and Pacific Sand Lance (Ammodytes personatus) on 32 occasions during vessel-based cetacean surveys around Cormorant Island between 2010 and 2014. Although Minke Whales are relatively uncommon in British Columbia, these results indicate that they can regularly be found in specific feeding areas during the summer.

An Indigenous Model of a Contested Pacific Herring Fishery in Sitka, Alaska

This paper uses GIS and spatiotemporal analysis of a historically and culturally modified marine ecosystem to evaluate Pacific herring abundance, declines, vulnerabilities, and future prospects, about which a Native Tribe and state fisheries managers disagree. In 2008, the Sitka Tribe of Alaska (STA) requested that an area within its traditional waters be closed to commercial sac roe fishing to protect spawning Pacific herring (Clupea pallasi), a key species for Native subsistence and marine ecosystem health. This proposal was opposed by the Alaska Department of Fish and Game (ADF&G), which estimated that adequate biomass was available to accommodate all herring users' needs. The disagreement exposes divisions between the Tribe's and the State's conceptualizations of the status, health, and management priorities for fisheries and marine ecosystems. The Tribe's model is one of cultivated abundance, wherein herring eggs are harvested conservatively and habitat is enhanced to make coastal spawning areas more productive, stable, and resilient. The State's paradigm, in contrast, follows a constitutional mandate to manage fisheries for Maximum Sustained Yield (MSY). A single-species biomass model is used to estimate a “surplus” herring for commercial roe harvesting within management areas. This work analyses and compares the spatiotemporal prescriptions of State and Indigenous models of herring fisheries management as they are used within debates over a closed area (Proposal 239), and assesses their relative potential for improving herring fisheries and marine ecosystem management using a combination of GIS spatial and scientific analysis and traditional ecological knowledge.