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Collaborative Research: Demographic structure and recruitment patterns of the scyphozoan, Chrysaora melanaster, in the Bering Sea: the influence of climate on ecosystem function

General

Organisation
Project start
01.01.2016
Project end
31.12.2019
Type of project
ARMAP/NSF
Project theme
Ocean & fiord systems
Project topic
Oceanography

Fieldwork / Study

Fieldwork country
Arctic Oceans and various regions
Fieldwork region
North Pacific
Fieldwork location

Geolocation is 59.22399902344, -177.71499633789

Fieldwork start
28.07.2017
Fieldwork end
05.08.2017

SAR information

Fieldwork / Study

Fieldwork country
Arctic Oceans and various regions
Fieldwork region
North Pacific
Fieldwork location

Geolocation is 59.22399902344, -177.71499633789

Fieldwork start
05.07.2018
Fieldwork end
11.07.2018

SAR information

Project details

02.09.2019
Science / project summary

In the eastern Bering Sea, jellyfish biomass increased dramatically after 1990 and peaked in 2000. Biomass increased again during the cool period of 2007-2012. Overall, moderate to cold conditions tend to favor jellyfish in this system. During times of population increase, jellyfish likely have major impacts on the Bering Sea food web, including Walleye Pollock fisheries, because the medusae directly feed on young life stages of fish and compete with fish for food. This project will estimate the age structure and age-specific abundances of the predominant jellyfish in the Bering Sea, Chrysaora melanaster, and will relate this to adult medusa abundance in order to understand how their population structure changes with time. The ultimate goal is to estimate the reproductive capacity and success of this jellyfish in relation to climate variability and to investigate the potential for increases of this jellyfish to become a recurring pattern in the Bering Sea given future climate scenarios. This project will contribute to STEM workforce development through the support for the training of a graduate student. The investigators will participate in K-12 teacher training workshops. Undergraduate students will be entrained into the research through an existing Research Experience for Undergraduates program. Elementary school students will be introduced to marine science through visits to the principal investigator's laboratory. A website for the project, including novel imagery, will be developed. Open-source code for image processing will be posted on the World Wide Web as a resource for the larger scientific community. The importance of incorporating age-specific abundances and age structure in assessments of the population dynamics of a species in relation to environmental change is well-established in fisheries science and other disciplines that attempt to understand the temporal variation of populations. Rigorous investigations will be conducted to estimate the abundance and fine-scale spatial distribution of C. melanaster including both their early planktonic and adult stages, to determine their age structure, and to construct a population model to identify recruit success and recruitment timing. This research will examine how gelatinous zooplankton populations respond to large scale environmental changes and will also facilitate understanding of the reoccurring jellyfish population increases in the Bering Sea. The sonar imaging technologies (ARIS1800) are effective in sampling adult forms of the congener C. quinquecirrha and an advanced optical ZOOplankton VISualization (ZOOVIS) system can sample small jellyfish effectively. The combination of net sampling and new aging techniques will provide much needed information on the age-structure within cohorts and will facilitate understanding of recruitment processes, e.g. single cohort versus multiple cohorts. This will in turn enable forecasting of jellyfish abundance and their predatory impacts in the Bering Sea ecosystem.

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