Effect of flow speed on fish feeding kinematics

Supervised By: Victor ChinaAdam Cockburn, Joshua Eisenstat, Zane Grossinger, Joshua

David Holtzman, Micah Maerov, Sam Neumark

Introduction:

How do planktivorous fish feedFish feed by using suction. They rapidly

increase the volume of their oral cavity creating an area of low pressure. This results in an inward water flow carrying its prey into its mouth.

20 times slower than real life

?Who is our fishOur fish is the Chromis viridis.This green and yellow fish is a species of

Damselfish found within the Gulf of Aqaba that feeds on plankton.

Previous studies have shown that this type of fish is able to adjust its feeding kinematics for different prey types.

Mussels and flow speedOther marine life have proven to modulate

their feeding kinematics based on ambient flow speed

In previous studies Mussels have shown the ability to fulfill this action

Our projectIn our studies, we search to find the effect

of the ambient flow speed on the feeding behavior (feeding strike kinematics) of the Chromis viridis.

Methods:

Methods for Data AcquisitionIn order to obtain the feeding kinematics data of

our fish, we used a high speed camera and a flow tank.

Methods for Data AcquisitionA total of nine fish were used for the experiment.

The fish were captured and transferred into the lab along with the coral that they lived in.

Methods for Data AcquisitionTwo hours before the

filming, the flow speed was set so that by the time of the filming, the fish would already be accustomed to the new flow speed. The fish were not fed anything prior to the filming in order to ensure that they would be hungry at the time of the data acquisition.

Methods for Data AcquisitionFeeding was measured at three flow speeds:

2.5 cm/s, 5 cm/s, and 7.5 cm/s.

Methods for Data AcquisitionThe fish were fed using a peristaltic pump,

which pumped a type of crustacean larvae called Nauplii into the flow tank. The pump was activated at the same time as the camera. As soon as feeding strikes were filmed, the pump was stopped.

Methods for Data AcquisitionThe flow tank was illuminated by a 1000W

LED light. The camera was set at 500 frames per

second. The camera buffered video for three seconds,

so when feeding was evident, the camera and food supply were immediately stopped. The previous three seconds were saved.

ImageJ Software• Our group used ImageJ software to analyze

videos and to obtain information on the parameters of interest from our high speed videos. We were able to create a scale and calibrate our measurements using a ruler we had recorded before taking videos of the fish feedings. Using the ImageJ measuring tools, we collected data on the parameters of interest.

Data Analysis

This picture shows how ImageJ was used to measure and collect data under the maximum gape size parameter of our research project. Using ImageJ, you can either measure the distance using pixels, or using a scale of your choice that you can set up.

Data Analysis

Data Analysis Four main parameters were chosen and measured for this project. The four parameters were:1. Maximal Gape Size2. Time to Peak Gape3. Gape Protrusion4. Food Distance

Data ResultsWe found: feeding distance increased with

flow speed Other kinematic parameters were not

influenced by flow speed

2.5 5 7.50

0.2

0.4

0.6

0.8

1

1.2

1.4

Food Distance vs. Flow Speed

Flow speed (cm/s)

Food d

ista

nce

(rel.

to

max.

gape)

ConclusionsChromis changed their timing in order to

compensate for the faster flow speed. Other kinematic parameters were not

influenced by the change in flow speed. This means that the flow speed is indeed

integrated into decision making.We believe that the Chromis do this because

they are able to anticipate the faster approaching food.

ConclusionsIn order to further extend our study, we could

increase the range and number of flow speeds and consider measuring more kinematic parameters such as: The timing of food entering the mouth. The overall parameters of the strike against

the varying sizes of the Chromis viridis.The addition of more species of fish into the

study.

Thank You!!!!!

Rabbi BuckmanNoam JosephVictor ChinaRachel Carr

Brad KitchenEveryone!