A large spatial closure to protect leatherback sea turtles greatly effect the California Drift Gillnet fishery, but did not have unintended negative consequences. Also, a decline in CPUE and effort for the fishery preceded the closure.
Not all fisheries dependent data tell the same story. Runcie et al. 2018 in Fisheries Oceanography shows how different fisheries and different gears show different preferences when fit with habitat models. It highlights an inherent difficulty in understanding the underlying habitat of a highly migratory predator from spatially restricted datasets.
I joined the Stellwagen Bank National Marine Sanctuary research team in 2005 and completed a large part of my PhD research there on fine scale foraging decisions of humpback whales. Theresa, a recent graduate from OSU, picked up the torch looking at the role of prey in structuring predator foraging decisions, using two vessels, archival tags, and EK60 acoustics. Kirchner et al. found that whale foraging bout size was linked to inter-patch-interval thus highlighting the role that spatial scale of prey plays in structuring the environment.
Just because data on rare species bycatch is sparse and from multiple sources does not mean it is useless for fisheries management. Welch et al. show that correlations can be used to assess and improve the enactment of a seasonal closure.
Figure shows SST anomalies were correlated with sightings and increased interactions with loggerhead turtles. Historical closures are shown with black rectangles. Continue reading
With the Bakun upwelling index almost 30 years old, a new publication by Mike Jacox explores two new indices derived from modeled vertical velocity: CUTI (coastal upwelling and transport index) and BEUTI (biologically effective upwelling and transport index). Mike has also provided a history of the upwelling indices focusing on where the indices agree and diverge. The publication is available in early view at JGR. Continue reading
We are excited to have Stefan join the team, moving from his position in Bremen to our cooperative institute at UC Santa Cruz. During his PhD, Stefan used interdisciplinary methods to investigate the impacts of ongoing ocean warming and acidification on the marine ecosystem and human user groups in the sub-arctic Barents Sea. He developed and applied integrative ecological models that incorporate experimental and observational data on biological processes as well as the input of local stakeholder groups. The models allow to assess future shifts in marine fish stocks, food web-mediated impacts on marine mammals and seabirds, and changes in ecosystem functioning. They are used to develop feasible and fair strategies for ecosystem-based governance of climate change impacts in the marine realm. We are excited to have Stefan join the team and help develop similar models for the California Current!
When building an operational tool, building the ecological models is only part of the equation. Equally important is ensuring that we have operational tools and regular predictions for use in management. Welch et al. 2018 explore the operational-side of the EcoCast tool, including potential pitfalls and solutions towards decision making. The paper came out in early view in the Journal of Applied Ecology and there is a discussion on the steps involved in creating fisheries nowcasts in the Conversation.
Figure 1. The four stages of operationalizing a dynamic management tool (hollow fill) and internal components (grey fill). The framework is relevant to operationalizing tools at one point in time and does not encompass tool updates as new data become available.
Elucidating connections between ocean climate variability and change, and recruitment of juvenile fishes to adult populations, is critical for understanding variability in stock-recruit dynamics. Recruitment to adult rockfish populations in the California Current Ecosystem (CCE) is highly variable, leading to short and long-term changes in abundance, productivity, forage availability and potential fisheries yield. We used regional ocean model output, oceanographic data, and a 34-year time series of pelagic juvenile rockfish, to investigate the interaction between changes in CCE source waters as reflected by physical water mass properties and recruitment variability. Specifically, variability of spiciness on upper water isopycnals explains a substantial fraction of the variation in pelagic juvenile rockfish abundance. High rockfish abundances correspond to cooler, fresher waters with higher dissolved oxygen (i.e., minty) conditions, indicative of Pacific Subarctic Water. By contrast, years of low rockfish abundance are associated with warmer, more saline, and more oxygen deficient (i.e., spicy) conditions, reflecting waters of subtropical or equatorial origin. Transport and source waters in the CCE are key factors determining density-independent processes and subsequent recruitment to adult populations.
We are excited to have Megan join the team, moving from her position in UC San Diego to our cooperative institute at UC Santa Cruz. Her Ph.D. research investigated the effects of climate change on Pygoscelid penguins in the Southern Ocean by using underwater robots, animal-borne tags, habitat modeling approaches, IPCC global climate models, and multi-decadal satellite, weather and penguins observations. This research addressed multidisciplinary questions (climate change effects, changes in demography, predator-prey dynamics, interspecific competition) across multiple trophic levels and scales. As a post-doc at the Scripps Institution of Oceanography in the Coastal Observing Research and Development Center, she used autonomous robots in novel ways to study jellyfish distribution in a marine lake, a snapper spawning aggregation, and detect tagged and vocalizing animals. She is excited to join NOAA ERD where her work will continue to understand the bio-physical factors that drive species distributions and movements on multiple spatiotemporal scales with the ultimate goal of aiding in conservation and management.
Future Seas is a project exploring potential impacts of climate change on the swordfish, albacore, and Pacific sardine fisheries in the California Current System. A suite of dynamical, statistical, and conceptual models is being applied to explore future scenarios in an “end-to-end” framework spanning physical changes to socio-economic consequences, and to evaluate uncertainty associated with individual elements of the modeling framework.