Fiscal Year
2014
Title
Field survey of rocky shore ecosystem in Shizugawa Bay
Project and Theme
Project 1. Study on ecological succession of fisheries ground
Representative Organization: Tohoku University
Theme2. Ecosystems and genetic researches to conserve and restore the coastal fisheries areas in Miyagi Prefecture| Representative person | Yukio Agatsuma |
|---|
| Organization | Tohoku University |
|---|
| Department | Graduate School of Agricultural Science |
|---|
Research InformationPeriod and Interval2014/04/01 - 2015/03/31
monthly
Research Area
CategoryField survey
OverviewLarge perennial kelp Eisenia bicyclis provides foods for commercially important organisms such as sea urchin Strongylocentrotus nudus and abalone Haliotis hannai hannai. We study the effect of tsunami and subsidence on population dynamics of the kelp, sea urchin, and abalone. We also study cultivation methods for sea urchins and commercially important kelp Undaria pinnatifida.
Overview of the Observation
Results and Future PlanA monitoring survey at a permanent study in the coast of Bentenzaki, inner part of Shizugawa Bay, showed that adult kelp Eisenia bicyclis disappeared from the area between 60-80m (5.9-7.5m in water depth) offshore from the base point, corresponding to an increase of sea urchin Mesocentrotus nudus density from November 2013 to February 2014. Although sea urchin distribution expanded toward 20m offshore (3.1m in water depth) from the base point since February 2014, decrease of Eisenia population size there didn't observed by September 2014.
Survey on the sea urchin M. nudus at 5 sites showed that there area no clear differences of size distribution trait from last year but post-tsunami cohort became bigger in their test diameter. Average density at some sites decreased from 2013 to 2014, suggesting the effect of fishery. The relation between these sea urchin and Eisenia distribution is now being analyzed.
Cage culture of the sea urchin M. nudus improved its gonad index, cohort, firmness. Free amino acid analysis showed that sweet-tasted alanine and serine increased and bitter-tasted arginine and lysine decreased in gonads of cultured sea urchin. Sensory evaluation by fishermen indicated high score at cultured urchin.
Fertilizer application for field Undaria culture didn't affect number of individuals and total weight of each strain but increased each individual's weight. It also decreased B-value which indicates blue reflected light.
Investigation Item and Data Acquisition
| Investigation Item | Data Acquisition |
|---|
| Large perennial kelp Eisenia bicyclis | Density |
| Sea urchin aquaculture | Body size(test diameter), gonad size and quality after cultivation |
| Cultivated kelp Undaria pinnatifida | Wet weight, nitrogen concentration |
| Environmental condition | Light and nutrient conditions, temperature, sediment |
Reference
Related Observation Plan
Related Observation Data
Person in charge of Investigation
| Representative person | Yukio Agatsuma |
|---|
| Organization | Tohoku University |
|---|
| Department | Graduate School of Agricultural Science |
|---|
| Representative person | Hikaru Endo |
|---|
| Organization | Tohoku University |
|---|
| Department | Graduate School of Agricultural Science |
|---|
| Fiscal Year | 2014 |
|---|
| Organization | Tohoku University |
|---|
| Category | Field survey |
|---|
| Research Area | South Sanriku |
|---|
| Discipline | Ocean physics -> Water temperature
Ocean physics -> Ocean current / Tidal current (Current direction/Current speed)
Ocean physics -> Others
Ocean chemistry -> Nutrients
Ocean environment -> Nutrients
Ocean biology / Ocean ecology -> Biomass
Ocean biology / Ocean ecology -> Physiology
Ocean biology / Ocean ecology -> Ecology
Ocean biology / Ocean ecology -> Sea algae
Ocean biology / Ocean ecology -> Seaweed beds / Tidal flats distribution
Ocean biology / Ocean ecology -> Others
Topography / Geology / Geophysics -> Seabed morphology
Topography / Geology / Geophysics -> Bottom sediment
Topography / Geology / Geophysics -> Marine sediments
|
|---|
