Small Fish Surveys – 2014
Kathryn Nelson, Research Officer
Contents
Introduction ............................................................................................................................... 2
Aims............................................................................................................................................ 2
Sites ............................................................................................................................................ 2
Chichester Harbour .................................................................................................................... 3
Introduction ........................................................................................................................... 3
Results .................................................................................................................................... 4
Cuckmere ................................................................................................................................... 6
Introduction ........................................................................................................................... 6
Results .................................................................................................................................... 7
Rye.............................................................................................................................................. 9
Introduction ........................................................................................................................... 9
Results .................................................................................................................................. 10
Medmerry ................................................................................................................................ 13
Introduction ......................................................................................................................... 13
Results .................................................................................................................................. 14
Discussion................................................................................................................................. 15
Summary .............................................................................................................................. 15
Partnerships ......................................................................................................................... 15
Diversity ............................................................................................................................... 15
Other surveys ....................................................................................................................... 16
Conclusion ................................................................................................................................ 16
Acknowledgements.................................................................................................................. 16
1
Introduction
The fish populations of the UK, together with the fisheries they support, are of enormous
environmental, social and economic value. Environmentally, fish are a major contributor and
component of aquatic communities and are a key module in the majority of marine and estuarine
food webs. They are a good general indictor of ecological status and habitat health. In addition, fish
are commonly used as specific indictors to monitor change in the marine environment for example,
temperature (climate change) and water quality (the effects of urban development and pollution).
The near-shore marine environment provides valuable commercial and recreational fisheries, in
addition to a multitude of other activities from water sports to renewable energy.
The near shore marine and estuarine environments commonly have high productivity and high
biodiversity. These zones are home to many small fish species, from those which have evolved to be
adapted to the specific near-shore conditions and remain in-situ for the majority of their life-cycle
(e.g. gobies and sticklebacks) to species which utilise the near shore environment during vulnerable
stages in their life cycle, for example as ‘nursery’ grounds where the juveniles of larger fish species
use the features of the near-shore area for shelter (e.g. bass, herring and sprat).
It is mutually beneficial for the Water Framework Directive (WFD) and for the sampling of juvenile
bass for surveys to be conducted during;
 May-June, termed ‘Spring’ survey period
 September-October, termed ‘Autumn’ survey period
Outside of these months the data will either be non-compliant with the WFD or is likely to miss the
targeted 1-gp and 0-gp bass (spring and autumn respectively). However, in Rye the purpose of the
small fish survey was to link the small fish population to the breeding success of the local terns.
Therefore, sampling was conducted monthly from April to September.
The value of the surveys is not only in the data collected, that can inform management decisions in
relation to statutory drivers and in monitoring Marine Protected Areas, but also in the mutual
benefit of partnership working and the sharing of resources and data.
Aims
The objective of monitoring small fish communities is to develop a time series of biodiversity and
relative abundance in these highly productive near shore habitats. There is particular interest in
species that are commercially important and that are important as a food source for other species
such as terns. The information collected will have many applications such as:
 To gain an understanding of the current health of these communities
 To provide evidence to guide any actions that may be required to improve the health of
these communities
 To monitor these communities over time and in relation to any specific or on-going events
 To investigate the auto-ecology of fish species
 To monitor the juvenile stocks of commercially important species
Sites
Small fish surveys were conducted at four locations in the Sussex IFCA district in 2014; Chichester
Harbour, Cuckmere, Rye and Medmerry.
2
Chichester Harbour
Introduction








In collaboration with Chichester Harbour Conservancy and with support from the University
of Portsmouth, the Wildlife Trust, West Sussex County Council, Natural History Museum
London and Environment Agency
17 people from 8 organisations
Surveys have been conducted since 2010
2m beam trawl
43m seine net
Three sites: Pilsney, Marker and Copperas (Figure 1)
June 16th and 17th
o 16th High tide at 15:00 (Marker)
o 17th Low tide at 08:30 (Pilsney) and high tide at 16:00 (Copperas)
o Overcast but warm and dry
o Water temperature: 18oC
September 11th and 12th
o 11th High tide at 14:00 (Marker)
o 12th Low tide at 07:30 (Pilsney) and high tide at 14:45 (Copperas)
o Partially overcast with a light northerly wind
o Water temperature: 18oC
Figure 1: Location of the 2014 survey sites (blue line is the SxIFCA district boundary)
3
Results
0%
10%
Relative abundance
20%
30%
40%
50%
Species
Goby - common
Bass
Goby - rock
Sand smelt
Goby - sand
Herring
Herring/Sprat - juvenile
Goby - juvenile
Mullet - thin lipped
Wrasse - Corkwing
Wrasse - Ballan
Sprat
Mullet - golden grey
Dragonet - Reticulated
Goby - black
Mullet - red
Sea Scorpion - Long-spined
Bream - Black
Garfish
Goby - painted
Mullet - thick lipped
Flounder
Pipefish - Greater
Figure 2: Percentage of total abundance for each species found in Chichester Harbour in 2014, June
and September combined.
No. of species
Total abundance
Index of diversity
June




June
19
1273
0.51
September
17
3491
0.56
Both
23
4764
0.55
Most abundant species was bass Dicentrarchus labrax
(856), 98% of which were caught at Marker
Second most abundant species was herring Clupea
harengus (223)
Bass and herring made up 85% of the total abundance
Pilsney: most number of species (12), including garfish
Belone belone new to this survey
Simpson’s index of diversity:
1=infinite diversity
0=no diversity
Garfish
4


Marker: highest abundance (918) but lowest diversity (0.15) as it was dominated by bass
Copperas: least number of species (4), least abundance (41) but highest diversity (0.72)
September






Most abundant species was common goby
Pomatoschistus microps (2106), 99% of which were
caught at Copperas with an average length of 35mm
Second most abundant species was bass Dicentrarchus
labrax (579)
Common goby and bass made up 77% of the total
Red mullet
abundance
Pilsney: most number of species (14), including red mullet Mullus surmuletus new to this
survey, and the highest diversity (0.74)
Marker: least number of species (4) and least abundance (429)
Copperas: highest abundance (2426) but lowest diversity (0.24), as it was dominated by
common goby
Bass
In the spring, there was a total of 856 bass and 76% were 90-139mm total length, considered to be
group 1 bass. In the autumn, there were 579 bass and 70% of them were less than 69mm,
considered to be group 0 bass, hatched this year.
80%
70%
Relative abundance
60%
50%
40%
30%
June
20%
Sept
10%
0%
1-69
70-89
90-139
140-169
170-209
>210
Gp-0
0-1
Gp-1
1-2
Gp-2
2+
Size classes (total length mm) and age classes
Figure 3: Relative abundance of bass in Chichester Harbour in 2014.
Comparison


Spring 2014 compared to the other spring surveys had the second highest number of
species, third most abundance, second lowest diversity and highest number of bass.
Autumn 2014 compared to the other autumn surveys had the lowest number of species,
second most abundance, lowest diversity and second most number of bass.
5
Cuckmere
Introduction







In collaboration with Environment Agency and South Downs National Park Authority with
support from the Wildlife Trust, Friends of the Cuckmere and the Angling Trust
22 people from 8 organisations
Surveys have been conducted since 2013 by SxIFCA, by EA 2005-07
43m seine net
Two sites: Seven Sisters 1 and Seven Sisters 2 (Figure 4)
June 3rd
o Low tide at 09:20 (SS1)
o High tide at 15:30 (SS2)
o Overcast with drizzle in the morning
o Water temperature: 16oC
October 1st
o Low tide at 10:20 (SS1)
o High tide at 15:30 (SS2)
o Showers in the morning, sunny in the afternoon
o Water temperature: 18oC
Figure 4: Location of the Cuckmere survey sites.
6
Results
Relative abundance
0%
10%
20%
30%
40%
50%
Bass
Mullet - thin lipped
Species
Sand smelt
Goby - Sand
Goby - Common
Mullet - golden grey
Flounder
Mullet - thick lipped
Figure 5: Percentage of total abundance for each species found in Cuckmere in 2014, June and
September combined.
June
October
Both
7
4
8
Total abundance
129
399
528
Index of diversity
0.82
0.59
0.70
No. of species
Simpson’s index of diversity:
1=infinite diversity
0=no diversity
June




Most abundant species was sand smelt Atherina presbyter (39), 90% of which were caught
at SS2
Second most abundant species was sand goby Pomatoschistus minutus (24)
Sand smelt and sand goby made up 49% of the total abundance
Seven Sisters 1: most number of species, highest abundance
and highest diversity
September




Most abundant species was bass Dicentrarchus labrax (202)
Second most abundant species was thin lipped mullet Liza
Thin lipped mullet
ramada (154)
Bass and thin lipped mullet made up 89% of the total abundance
Seven Sisters 1: most number of species, highest abundance and highest diversity
7
Bass
In the spring, there was a total of 16 bass and 69% were 90-139mm total length, considered to be
group 1 bass. In the autumn, there were 202 bass and 34% of them were less than 69mm,
considered to be group 0 bass, hatched this year. However, 42% were 90-139mm.
70%
Relative abundance
60%
50%
40%
30%
June
Oct
20%
10%
0%
1-69
Gp-0
70-89
90-139
140-169
170-209
>210
0-1
Gp-1
1-2
Gp-2
2+
Size classes (total length mm) and age classes
Figure 6: Relative abundance of bass in the Cuckmere in 2014.
Comparison


Spring 2014 compared to the other spring surveys had the second highest number of
species, second least abundance, second highest diversity and third highest number of bass.
Autumn 2014 compared to the other autumn surveys had the lowest number of species,
third most abundance, second lowest diversity and third most number of bass
8
Rye
Introduction












In collaboration with Natural England, Environment Agency and Rye Harbour Nature Reserve
with support from the Wildlife Trust, Romney Marshes Area Internal Drainage Board and
University of Brighton.
28 people from 7 organisations
Surveys have been conducted since 2013
43m seine net from Rye beach April-September at 3
hours before low tide, 1.5 hours before low tide and
at low tide
2m beam trawl in Rye Bay and off Hastings in
September
April 9th: Low tide at 14:00, water temperature 12oC
May: Attempts were made on 9th and 23rd but too
rough for safe successful sampling
June 9th: Low tide at 15:30, water temperature 18oC
July 8th: Low tide at 14:30, water temperature 19oC
August 19th: Low tide at 13:15, water temperature
18oC
September 4th: Low tide at 13:15, water
temperature 20oC
September 2nd and 3rd: Beam trawling in Rye Bay, 6
stations and Hastings, 3 stations
Figure 7: Location of the Rye survey sites; seine netting on Rye beach and survey beam trawling in
Rye Bay and off Hastings.
9
Results
Species
0%
Relative abundance
20%
30%
40%
10%
50%
60%
Herring/sprat - juvenile
Solenette
Goby - Sand
Bass
Dab
Herring
Sprat
Sand smelt
Plaice
Dragonet - Reticulated
Weaver - Lesser
Sole - Dover
Goby - Transparent
Pouting
Whiting
Brill
Mullet - thick lipped
Mullet - golden grey
Anchovy
Blenny - Shanny
Hooknose
Mullet - thin lipped
Flounder
Tub gurnard
Thornback ray
Goby - Common
Pipefish - Greater
Pipefish - Lesser
Smelt
Rockling - five bearded
Sole - sand
Figure 8: Percentage of total abundance for each species found in Rye in 2014, methods and months
combined.
April
June
July
August
September
Trawling
All
No. of species
12
15
18
15
18
21
31
Total abundance
73
378
449
490
495
8807
10692
Index of diversity
0.86
0.67
0.83
0.76
0.80
0.64
0.74
Simpson’s index of diversity:
1=infinite diversity
0=no diversity
Simpson’s index of diversity is a measure of how many
species are in the sample and how evenly individuals are
distributed among those species.
10
April


Most abundant species was lesser weever Echiichthys vipera (15)
Second most abundant was thin lipped mullet Liza ramada (13)
June


Most abundant species was sand smelt Atherina presbyter (151)
Second most abundant was herring Clupea harengus (140), 61%
caught at LW-1.5hrs and 35% at LW
Brill
July


Most abundant fish was juveniles of either herring Clupea harengus or sprat Sprattus
sprattus (160). The average length was 29mm which is too small to tell the difference. All
were caught at LW-3
Second most abundant species was sand goby
Pomatoschistus minutus (53)
August


Herring
Most abundant species was bass Dicentrarchus labrax (179)
Second most abundant was sand goby Pomatoschistus minutus (145)
September


Most abundant species was bass Dicentrarchus labrax (170)
Second most abundant species was sprat Sprattus sprattus (124)
September Rye Bay


Most abundant fish was juveniles of either herring Clupea
harengus or sprat Sprattus sprattus (4802)
Second most abundant species was solenette Buglossidium
luteum (1159)
September Hastings


Bass
Most abundant species was solenette Buglossidium luteum
(457)
Second most abundant was juveniles of either herring Clupea harengus or sprat Sprattus
sprattus (452)
Other species
Other conspicuous non-fish species included: squid (Loligo sp. and Alloteuthis sp.), squid eggs,
cuttlefish (Sepia officianalis and Sepiola atlantica), shrimps (Crangon spp.), rayed trough shell
(Mactra stultorum), spiny cockle (Acanthocardia aculeata),
necklace shell (Euspira catena), netted dog whelk (Nassarius
reticulatus), sea gooseberries (Pleurobrachia bachei), sea
potato (Echinocardium cordatum), starfish (Asterias rubens),
brittle stars (Ophiurida spp.), swimming crab (Liocarcinus
holsatus), hermit crabs (Pagurus spp.), spider crab (Maja
brachydactyla), masked crab (Corystes cassivelaunus), sea
mouse (Aphrodita aculeata) and sea chervil bryozoan
(Alcyondium diaphanum).
11
Bass
In April there were no bass. In June there were 7 bass, 86% 170-209mm total length, considered to
be group 2 age class. In July (29, 90%), August (179, 87%) and September (170, 66%) the majority of
bass were less than 69mm, considered to be group 0, hatched that spring. There was only one bass
caught by the beam trawl and it was 250mm total length.
90%
Relative abundance
80%
70%
60%
50%
June
40%
July
30%
Aug
20%
Sept
10%
0%
1-69
70-89
90-139
140-169
170-209
>210
Gp-0
0-1
Gp-1
1-2
Gp-2
2+
Length classes (mm)
Figure 9: Relative abundance of bass in Rye in 2014.
Comparison



There were differences in methods and sampling stations between 2013 and 2014 which
made direct comparison difficult.
However the relative abundance of the ten most abundant species can be seen in Figure 10.
In 2013, the three most abundant species were sand goby, solenette and herring and they
made 75% of the total abundance.
In 2014, the three most abundant species were very similar; herring/sprat juvenile, solenette
and sand goby, making 80% of the total abundance.
2013
Species
Goby - Sand
Solenette
Herring
Dab
Sole - Dover
Goby - Juvenile
Plaice
Herring/sprat juvenile
Dragonet - Reticulated
Weaver - Lesser
0%
Relative abundance
20% 40% 60%
2014
0%
Relative abundance
20% 40% 60%
Herring/sprat juvenile
Solenette
Goby - Sand
Bass
Dab
Herring
Sprat
Sand smelt
Plaice
Dragonet - Reticulated
Species

Figure 10: Comparison of the ten most abundant species in 2013 and 2014.
12
Medmerry
Introduction









In collaboration with Environment Agency and RSPB with support from the Wildlife Trust,
SC2 and Langstone Harbour Board
12 people from 6 organisations
Managed realignment site breached in September 2013
First year of survey, various sites and methods trialled
Drainage outfalls (DO), creeks and borrow pits (BP) sampled (Figure 11)
Seine nets: 43m, 35m and 15m
Fyke nets: single leader and double leader micromesh
July 3rd and 4th
o 3rd low tide at 09:15 set two fyke nets in the main Eastern
creek and one in the creek downstream from DO 1
o 4th low tide at 10:00 collect fyke from DO 1 creek, use hand net
in DO 1, collect fykes from Eastern creek and 43m seine net in Eastern creek
downstream from fykes
o Water temperature: 22oC
October 14th and 15th
o 14th low tide at 09:30 set one fyke net in the creek downstream from DO 4, two
hauls with the 15m seine in DO 4 and two hauls with the 35m seine net in BP 9
o 4th low tide at 10:00 collect fyke from DO 4 creek and use the 15m seine in DO1
o Water temperature: 13oC
Figure 11: Diagram of Medmerry managed realignment scheme, blue indicates water and the green
line is the flood defensive bund.
13
Results
Relative abundnace
0%
10%
20%
30%
40%
50%
Bass
Goby - Sand
Mullet - juvenile
Sand smelt
Stickleback - 3 spined
Species
Mullet - thin lipped
Wrasse - Corkwing
Goby - Common
Flounder
Herring
Mullet - golden grey
Goby - Juvenile
Pipefish - Worm
Plaice
Solenette
Figure 12: Percentage of total abundance for each species found in Medmerry in 2014, July and
October combined.
No. of species
Total abundance
Index of diversity
July
10
255
0.83
October
13
548
0.65
Both
15
803
0.74
Simpson’s index of diversity:
1=infinite diversity
0=no diversity
July




Most abundant species was sand goby Pomatoschistus minutus (64)
Second most abundant species was sand smelt Atherina presbyter (57)
Sand goby and sand smelt made up 47% of the total abundance
Seine netting in Eastern creek had the most number of species (7), highest abundance (148)
and highest diversity (0.70)
October




Most abundant species was bass Dicentrarchus labrax (293)
Second most abundant species was sand goby Pomatoschistus minutus (103)
Bass and sand goby made up 72% of the total abundance
DO 4 and DO1 had the joint most number of species (7), BP 9 had the highest abundance
(309) and DO4 had the highest diversity (0.70)
14
Bass
In the spring, there was a total of 32 bass and 31% were 90-139mm total length, considered to be
group 1 bass. However, 66% were less than 69mm. In the autumn, there were 179 bass and 55% of
them were less than 69mm, considered to be group 0 bass, hatched this year. However, 39% were
90-139mm.
70%
Relative abundnace
60%
50%
40%
30%
July
20%
Oct
10%
0%
1-69
70-89
90-139
140-169
170-209
>210
Gp-0
0-1
Gp-1
1-2
Gp-2
2+
Size classes (total length mm) and age classes
Figure 13: Relative abundance of bass in Medmerry in 2014.
Discussion
Summary
In total across all sites and months, there were 43 species and a total abundance of 16,769. Juvenile
herring/sprat were the most abundant (5532), followed by bass (2371), common goby (2172), sand
goby (1800) and solenette (1674). These five species made up 81% of the total abundance. The
average index of diversity was 0.70.
Partnerships
The surveys involved a total of 67 people from 20 organisations. The hard work and enthusiasm of all
those who took part is what made these surveys possible. The sharing of skills, knowledge,
experience and resources through partnership working has also been instrumental to the success of
the surveys, increasing efficiency, productivity and proficiency. It is hoped that these working
relationships will flourish in the future, with clear advantages for resource and time management.
Diversity
Comparison between the small fish surveys conducted in Chichester Harbour, Cuckmere, Rye and
Medmerry is difficult as different methods were used and there were different numbers of sites at
each location. However, as the Simpson’s index of diversity takes into account both the number of
15
species and the distribution of abundance across those species, it can be compared across sites. Rye
had the highest diversity (0.739) on average including all sites and months and Medmerry was a
close second (0.738). Chichester had the lowest diversity (0.553) as this was dominated by common
goby and bass. There were 7 species common to all four sites: bass, flounder, common goby, sand
goby, golden grey mullet, thin lipped mullet and sand smelt. The two locations with the most species
in common were Chichester and Rye (13). Rye had 16 species that were not found at the other
locations, Chichester Harbour 8 species, Medmerry 2 and Cuckmere none.
Other surveys
Small fish surveys are also conducted by other organisations including the Environment Agency and
Langstone Harbour Board. Langstone Harbour neighbours Chichester Harbour and lies within
Southern IFCA’s district. Three sites within the Harbour were surveyed in June and September using
a beach seine and beam trawl – the same as Chichester Harbour. This year, there was a total of 27
species and a total abundance of 7,837 in Langstone. The most common species was sand goby
(3031), followed by sand smelt (2185) and bass (1870). These three species made up 90% of the total
abundance. There were 14 species in common between Langstone and Chichester Harbours but
Langstone had 12 species that were not in Chichester and Chichester had 8 species that were not in
Langstone.
Conclusion
The ongoing monitoring of small fish populations is important to gain an understanding of the health
of the communities associated with highly productive near-shore habitats. It fulfils statutory drivers
and helps to inform the condition of important Marine Protected Areas. These surveys are part of an
ongoing monitoring program that is building up a time series of ecological trends and creating a
detailed picture of the biological health of inshore habitats. Partnership working has been
instrumental in the success of all of the small fish surveys this year and has strong benefits for future
surveys. The skills and experience of the participants has ranged from technical experts to
undergraduate students at the start of their career, creating cross-organisation opportunities for
learning, networking and increased competence. The support and enthusiasm of all of those
involved has been fantastic and there are opportunities to be involved again next year and in
following years.
Acknowledgements
A sincere thank you to all the volunteers and staff from the Environment Agency, Chichester Harbour
Conservancy, Natural England, West Sussex County Council, Hampshire and Isle of Wight Wildlife
Trust, Sussex Wildlife Trust, South Downs National Park Authority, Rye Harbour Nature Reserve,
Angling Trust, Friends of the Cuckmere, Langstone Harbour Board, Natural History Museum London,
Romney Marshes Area Internal Drainage Board, Royal Society for the Protection of Birds, SC2
consultancy, University of Portsmouth and University of Brighton.
16