Understanding the distribution of Fish Aggregating Devices ...

Understanding the distribution

of Fish Aggregating Devices

(FADs) in the western and

central Pacific Ocean

Eunjung KimUniversity of Hawaii at Manoa

Pelagic Fisheries Research Program

Friday, December 16, 11

Source: A. Fonteneau

Tuna purse seine FAD associated catch by species

● skipjack● yellowfin● bigeye


Research Approach


Research Approach

Advection (u,v)

Diffusion (D)


Research Approach

Advection (u,v)

Diffusion (D)

FADs


hypothesis

�fad(i) < �fad(i+1)

�N

�t=

�

�x(D

�N

�x) +

�

�y(D

�N

�y)� �

�x(uN)� �

�y(vN)� ZN

Advection (u,v)Diffusion (D)

D = L+U � L

1 + e�s(�fad�K)

u = au + Sp · d⇢faddx

v = av + Sp · d⇢faddy


hypothesis

�fad(i) < �fad(i+1)

�N

�t=

�

�x(D

�N

�x) +

�

�y(D

�N

�y)� �

�x(uN)� �

�y(vN)� ZN

Advection (u,v)Diffusion (D)

D = L+U � L

1 + e�s(�fad�K)

u = au + Sp · d⇢faddx

v = av + Sp · d⇢faddy

Fish movement is a function of FAD density


• Fisheries data (purse seine fishing set data)

- catch (presence)

- date

- location

- types of sets : natural log

drifting FAD (man-made)

anchored FAD (man-made)

How many FADs are there in the WCPO?Where are the FADs?


Types of sets

Photos D. Itano

Photos D. Itano

Photos D. Itano

log

drifting FAD

anchored FAD


Fisheries data

2006 2007

20092008

● log● dFAD● aFAD

PNG PNG

PNGPNG

PNGPNG

0"

2000"

4000"

6000"

8000"

10000"

12000"

2006" 2007" 2008" 2009"


➜ Understanding the process of how the

types of FADs are distributed will allow to

reproduce better FAD density fields for

Advection-Diffusion Reaction & FAD model.


Natural log

Monthly log set number in years of 2006-2010 & monthly

climatological rainfall in Port Moresby (PNG)rainfall (m

m)

log

sets

4000

3000

1000

2000

0

300

250

200

100

50

0

150

JAN MAR MAY JUL SEP NOV


http://en.wikipedia.org/wiki/Sepik

20˚N

10˚N

10˚S

20˚S

0

120˚E 140˚E 180160˚E 160˚W

Sepik River

Natural log


2006

2008

1150mm

950mm

Natural log & Rainfall


Anchored FAD (aFAD)


Anchored FAD (aFAD)

aFAD


Anchored FAD (aFAD)

• K nearest neighbor (KNN) classification

aFAD

d1 d2

d3 d4

d5

d6

d7

r


number of aFAD:4709

2155


0 2 4 6 8 10 12

distance (NM)

freq

uenc

y

Anchored FAD (aFAD)

• Distance frequency between the aFADs


Results

• The amount of log sets are correlated with rainfall.

• The high density of log sets are close to the mouth of the Sepik river.

• The geographic distributions of anchored FADs are concentrated in certain areas (Bismarck Sea, Solomon Sea).

• The realistic density of aFADs can be inferred by KNN.

• The distance between the aFADs are 4-7 nmi apart in PNG.


Future works

• Drifting FAD.

• Using particle tracking tool, reproduce the dFAD distribution (forward tracking or backward tracking)

• What drives the distribution of dFAD?

• Apply the FAD density to ADR&FAD model.


Thank you.


4

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Understanding the distribution of Fish Aggregating Devices ...

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