Ctenophores, jellyfish, anchovies, zooplankton and
menhaden -OH MY!
Jim UphoffMD DNR, Fisheries Service
Ctenophores, jellyfish, anchovies, zooplankton and
menhaden
Ctenophores, jellyfish, anchovies, zooplankton and
menhaden
represent important middle links in Chesapeake Bay
trophic and nutrient dynamics
represent important middle links in Chesapeake Bay
trophic and nutrient dynamics
Phytoplankton
Zooplankton
Don’t forget microbes!
What fisheries want!
Balanced nutrients and fishing
What fisheries fear!
Too many nutrientsToo many removals
A look at the middle of the food chain and a couple of mediators
(summer data)
It’s a Maryland-centric
look for now
Chesapeake Bay Menhaden Indices
-1.5-1
-0.5
00.5
11.5
2
2.53
3.5
Sta
nd
ard
ized
ind
ex
MD Juvenile
MD Age 1+
PRFC Age 1+
Menhaden in the Bay – indices of relative demand by bass (fc of regulations and year-class) and relative
exploitation by fishery have risen.
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20
40
60
80
100
120
140
160
0
2000
4000
6000
8000
10000
12000
14000Relative bassdemand
Relative Exploitaion
Mean 4 week peak sea nettle count (approximated from Breitburg and Fulford 2006) and MD bay anchovy seine
index (geometric mean).
0
200
400
600
800
1000
1200
1400
1600
1800
Mea
n J
elly
fish
Co
un
t
0
1
2
3
4
5
6
7
8
9
An
cho
vy G
M
Mean jellyfishcount
MD Anchovy GM
Bay Program Zooplankton Monitoring – trends in sea nettle and ctenophore biovolume geometric mean.
Note monitoring ends in 2002
00.2
0.40.6
0.81
1.21.4
1.61.8
2
Jell
yfis
h G
M
01
23
45
67
89
10
Cten
op
ho
re GM
jelly GM
Cteno GM
Ctenophores go up, anchovies go down.
01
23
45
67
89
10
Cte
no
ph
ore
GM
0
0.5
1
1.5
2
2.5
3
3.5
An
ch
ov
y G
M
Cteno GM
MD anchovy index
Anchovies are also subject to striped bass predatory demand. Demand index a function of
regulations and year-class success.
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1
2
3
4
5
6
7
8
9
An
ch
ov
y J
I
0
5
10
15
20
25
30
35
40
45
50
Rela
tiv
e b
as
s d
em
an
dAnchovy JI
Relative bassdemand
Sea nettle abundance index follows MD oyster biomass index (skipjack CPUE)
0
10000
20000
30000
40000
50000
60000
70000
Oys
ter
cpu
e (l
bs/
skip
jack
)
0
50
100
150
200
250
300
350
Pea
k n
ettl
e m
eanPounds/Skipjack
Nettle count
Exploratory linear regressions of community dynamics. All variables loge-transformed. Yellow indicates P < 0.05.
C=count & B=biovolume.
Comparison r2 N
Oyster & nettle C + 0.32 20
Nettle B & ctenophore B 0.06 18
Nettle B & ctenophore B
Category (threshold?)
0.53
(- ?)
18
Nettle C & ctenophore B -0.35 12
Ctenophore B & anchovy -0.48 18
Nettle C & anchovy +0.22 38
Anchovy & striped bass -0.24 46
So far, things are acting logically; anchovies (high predation) & menhaden (high predation &
exploitation) replaced by ctenophores as sea nettles drop.
Comforting, ain’t it?
Based on my fishing observations, impervious surface sampling over the past 2 years,
and 34 years of experience
it looks to me like ctenophores have also dropped to a low level and others don’t appear to be
increasing!
Presence-absence of ctenophores has fallen in our impervious surface study. Brackish tributaries, same 2003-2005. Corsica only one continuously sampled.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
2003 2004 2005 2006
Pro
po
rtio
n w
/ ct
eno
0
2
4
6
8
10
12
N system
s
P/N cteno
Corsica P/N
Systems
We had this. Now we have this
?
This might mean something!What’s happening to the food chain?
We should look into this!
OOPS!No more Baywide monitoring!
MEAN SUMMER BAY ACARTIA DENSITYCB3.3C-CB4.3C-CB5.2 1985-2002
0
5
10
15
20
25
30
35
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02
#/L
ITE
R
CB3.3C CB4.3C CB5.2
MEAN SUMMER ACARTIA, CTENOPHORE & ANCHOVY MD MESOHALINE BAY 1985-2002 (6)
0
5
10
15
20
25
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06
AC
AR
TIA
#/L
ITE
R
0
1
2
3
4
5
CT
EN
OP
HO
RE
BIO
VO
LU
ME
ML
S/2
00 &
MD
AN
CH
OV
Y
ACARTIA CTENOPHORE ANCHOVYSeries4 Series5
MEAN SUMMER ACARTIA DENSITY & FILAMENTOUS CYANO CARBON 1985-2002 (6)
0
5
10
15
20
25
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06
AC
AR
TIA
/LIT
ER
0
50
100
150
200
250
CY
AN
O C
ug
C/L
ACARTIA CYANO C
Feedback from memo
• Mike Lane – ODU
• U-shaped trend in primary production
• Primary production correlated with DIN or DIN:DIP
• Increasing cyanobacteria abundance
Feedback from memo
• Claire Buchanan – ICPRB
• Prototype mesozooplankton IBI declining 1976-2003
• Calvert cliffs mesozooplankton (Marcia Olson) 1976-1980
N/L: min=2.2, max=65.1, median=14.3
• CB 4.3 1998-2002
N/L: min=0.2, max=16.0, median=6.7
• Claire Buchanan – ICPRB
• Prototype mesozooplankton IBI declining 1976-2003
• Calvert cliffs mesozooplankton (Marcia Olson) 1976-1980
N/L: min=2.2, max=65.1, median=14.3
• CB 4.3 1998-2002
N/L: min=0.2, max=16.0, median=6.7
Feedback from memoFeedback from memo
• Denise Breitburg – SI• Denise Breitburg and Richard Fulford
did a very nice exploration of much of this (Estuaries and Coasts 2006 29:776-784)
• Late ctenophores and jellies not unprecented
• 2003 & 2007 were late
• Denise Breitburg – SI• Denise Breitburg and Richard Fulford
did a very nice exploration of much of this (Estuaries and Coasts 2006 29:776-784)
• Late ctenophores and jellies not unprecented
• 2003 & 2007 were late
Feedback from memo
• Thoughts from Peter Tango – CBP• Mesozooplankton low numbers could reflect:
– Decline in reproductive success– High powered microzooplankton grazing– High abundance of low nutrition
phytoplankton
• Ed Houde – CBL
• Regime shift thinking in vogue – be cautious
• Serves as preliminary hypothesis
• MD anchovy index may not be best
• MD Index accumulates fish of all sizes
• Most spawning in lower 1/3 Bay, most ctenophores too
• Hypoxia may be factor in interactions
• He’s wary anchovy abundance has shifted in last 2-4 years
• Ed Houde – CBL
• Regime shift thinking in vogue – be cautious
• Serves as preliminary hypothesis
• MD anchovy index may not be best
• MD Index accumulates fish of all sizes
• Most spawning in lower 1/3 Bay, most ctenophores too
• Hypoxia may be factor in interactions
• He’s wary anchovy abundance has shifted in last 2-4 years
In the last years of my career I think I will
begin to work on the microbial loop where
most of the energy and action is concentrated
Ed Houde
What’s Next?What’s Next?
This is my obligatory Three Stooges slide
This is my obligatory Three Stooges slide