Selective Field Collection of Juvenile Littorina littorea: Methods, Spatial Variability, and Sustainability Assessment
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Subject: Marine Biology
Level: Bachelor or master, 30-60 hp
Start: Spring 2026
Supervisor: Susanne Lindegarth
Location: Tjärnö marine laboratory
Background
The common periwinkle (Littorina littorea) is a dominant intertidal gastropod in the North Atlantic and a species of established culinary value, being a mandatory item on shellfish plateaus in southern Europe. Despite this, L. littorea is neither collected, farmed or marketed in Scandinavia. There is potential for developing farming practices for these snails with cost-effective methods, aimed for niche, top-end seafood restaurants in Sweden.
Juvenile L. littorea recruit naturally in high numbers in intertidal habitats, often forming dense cohorts associated with macroalgal cover and hard substrates. This natural recruitment suggests that selective collection of juveniles could represent a low-impact method for obtaining seed material for experimental aquaculture.
However, there is limited quantitative information on juvenile densities, spatial variability, and the potential ecological implications of juvenile collection methods in Nordic coastal systems.
This project addresses the need for field-based data and standardized methodologies for assessing whether juvenile collection for aquaculture purposes can be conducted in a controlled, selective, and ecologically responsible manner.
Objectives
- Develop and apply a standardized, quantitative method for collecting juvenile L. littorea in the intertidal zone.
- Quantify juvenile density, size structure, and spatial variability across multiple coastal sites.
- Estimate proportional removal under different collection intensities.
- Assess temporal variation in juvenile availability during the recruitment season.
- Discuss ecological and regulatory implications of juvenile collection as a seed strategy for aquaculture.
Methodology
Fieldwork will be conducted at 3–5 intertidal coastal sites during late spring and summer 2026. Data collected will include abundance, size class distribution, substrate type, and macroalgal cover. Analyses will focus on spatial and temporal variability, estimation of sustainable collection levels, and comparison between sites.
The project will primarily be field- and data-driven, with limited or no laboratory experimentation.
Contact
Susanne Lindegarth,
Project coordinator
Email: susanne.lindegarth@marine.gu.se