Marine Scotland Science: directory

Hannah Holah

Fisheries Data Programme
Fishing Gear Technology Group
Ichthyoplankton Biologist

E-mail: hannah.holah@gov.scot

Marine Scotland Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB, UK

Pronouns: she/her/hers

Details of specialism

In general terms I am interested in the distribution and abundance of ichthyoplankton in the North Sea and Eastern Atlantic, with particular focus on clupeid larvae and mackerel (Scomber scombrus) eggs. I am interested in the collection and identification of ichthyoplankton samples, the data from which is used to inform recruitment indices for stock assessments. I also work on image capture, image analysis techniques and their applications to ichthyoplankton ID. 

Within the broad topic area my role at Marine Scotland covers, the current focuses of my work include:

• undertaking fish larvae sampling using the mid-water ring net and MIKey-M attachments during the IBTS Q1 North Sea MIK survey
• carrying out at-sea and post cruise identification of target larval species. Considering improvements to the MIK survey to gather data on a wider variety of species
• carrying out fish egg sampling using the Gulf-7 sampler during triennial mackerel egg surveys as well as processing adult mackerel and horse mackerel including taking ovary and egg samples
• analysing mackerel ovary and egg samples in collaboration with other participating European institutes
• analysing, quality checking, and submitting ichthyoplankton data to the ICES Egg and Larvae Database
• investigating new uses of image capture and analysis software such as Qcapture, ImageJ, and ObjectJ for measuring and identifying fish eggs

Main policy links

• sea fisheries

External committees and responsibilities

• member of the ICES Working Group on Surveys on Ichthyoplankton in the North Sea and adjacent Seas
• member of the ICES Working Group on Mackerel and Horse Mackerel Egg Surveys
• member of the ICES Working Group on Atlantic Fish Larvae and Eggs Surveys
• deputy chair of the Marine Scotland Science Athena SWAN team
• committee member of Marine Scotland Women and Equalities Network
• founding member of Marine Scotland’s Early Career Scientist Network