Marine Fishes of the south-western North Sea. by Suffolk Naturalists' Society

MARINE FISH

MARINE FISHES OF THE SOUTH-WESTERN NORTH SEA GEN BROAD & JIM R. ELLIS Introduction In order to better understand the status of fish stocks in the North Sea and Atlantic waters, a range of western European nations participate in the International Bottom Trawl Survey (IBTS). These surveys are internationally co-ordinated by the International Council for the Exploration of the Sea (ICES) and have been running in the North Sea since the 1960s (ICES, 2015). These trawl surveys sample a range of bottom-living (demersal) fish and small pelagic fish, with catch information and biological data collected. These surveys provide consistent and standardized data on the species present, their relative abundance and distribution, size composition and, for commercial stocks, information on the age structure and length-at-maturity, and enable the status of the stocks to be monitored over time. The countries participating in the North Sea IBTS include Denmark, France, Germany, Netherlands, Norway, Sweden and the UK (Scotland and England). These data can also provide an important insight into which species occur in the different parts of the North Sea, although it should be noted that trawl surveys only sample a part of the wider fish community, and that trawl survey datasets can contain some erroneous records. The latter may relate to misidentifications of noncommercial species as well as coding errors (Daan, 2001; ICES, 2007; Heessen et al., 2015). This paper summarises the results from the IBTS for those waters around the coast of East Anglia during the period 2016–2020, thus providing some contemporary information on the marine fishes of the area. Methods The International Bottom Trawl Survey (IBTS) of the North Sea samples across the North Sea, including the Skagerrak and parts of the eastern English Channel (ICES, 2015). The gear used is a GOV trawl (chalut à Grande Ouverture Verticale), and the high headline of the trawl allows for small pelagic fish species to be sampled, as well as demersal fish. The trawl is typically towed for 30 minutes duration at predefined sites, the catches sorted and the fish measured (total length) to the cm below (i.e. fish of 240–249 mm are recorded as 24 cm), with herring and sprat measured to the 0.5 cm below. Participating nations upload these data to the DATRAS database, which is hosted by ICES (http://www.ices.dk/data/data-portals/Pages/DATRAS.aspx). The IBTS is conducted twice per year, in the first quarter (Q1) and third quarter (Q3). Data on the numbers-at-length of all fish species captured in the IBTS-Q1 and IBTSQ3 for the years 2016–2020 were extracted (on 13 Oct 2020) for the south-western North Sea (Roundfish Area 5; see ICES, 2015). This area extends from Kent to Lincolnshire, including the coast of East Anglia (Figure 1). The numbers of stations fished in Roundfish Area 5, by year and quarter, are summarised in Table 1. Some processing of those data extracted was undertaken prior to subsequent analyses. Firstly, due to the use of different taxonomic codes, some data nominally reported as genus were mapped to the relevant species. Secondly, data submitted for common smooth-hound Mustelus mustelus were assumed to relate to starry smooth-hound Mustelus asterias (see Farrell et al., 2009). Trans. Suffolk Nat. Soc. 56 (2020)

Suffolk Natural History, Vol. 56

Figure 1. Map of trawl sites by year (With thanks to SBIS) Table 1: Numbers of trawl stations sampled in Roundfish Area 5 (south-western North Sea) in the IBTS-Q1 and IBTS-Q3 by year (2016–2020). Year 2016 2017 2018 2019 2020 Sub-total Total Trans. Suffolk Nat. Soc. 56 (2020)

Q1 23 20 21 19 18 101

Q3 15 14 14 14 14 71 172

MARINE FISH

Results Between 2016–2020, a total of 83 fish species (and 90 taxonomic categories, including specimens only recorded to genus or family) were reported (Table 2), although this included one species record which was considered erroneous and likely relates to either a misidentification or coding error. Hence, there were records for 82 fish species in Roundfish Area 5. The record that was considered invalid was a nominal record of a 24 cm specimen of big-eye rockling Gaidropsarus macrophthalmus, as this species generally attains a smaller size and is more common on the outer continental shelf of the Atlantic. Several length records were also considered as suspicious (e.g. a 6 cm specimen of European eel Anguilla anguilla, a 15 cm specimen of Norwegian topknot Phrynorhombus norvegicus and a 19 cm specimen of scaldfish Arnoglossus laterna), and these records should also be used with caution. Table 2. Taxonomic list of fish species sampled in Roundfish Area 5 (south-western North Sea) in the IBTS-Q1 and IBTS-Q3 (2016–2020) and their reported length ranges. Taxonomic order based on the on-line Catalog of Fishes (https://www.calacademy.org/scientists/projects/catalog-of-fishes) Family

Scientific name

Common name

Petromyzontidae Scyliorhinidae Triakidae

Lampetra fluviatilis Scyliorhinus canicula Galeorhinus galeus Mustelus asterias Squalus acanthias Amblyraja radiata Leucoraja naevus Raja brachyura Raja clavata Raja microocellata Raja montagui Anguilla anguilla Alosa fallax Clupea harengus Sardina pilchardus Sprattus sprattus Clupeidae Engraulis encrasicolus Salmo trutta Zeus faber Gadus morhua Melanogrammus aeglefinus Merlangius merlangus

River lamprey Lesser-spotted dogfish Tope [1] Starry smooth-hound Spurdog Starry ray Cuckoo ray Blonde ray Thornback ray Small-eyed ray Spotted ray European eel Twaite shad Herring Pilchard Sprat Clupeid (indet.) Anchovy Sea trout John dory Cod Haddock Whiting

Squalidae Rajidae

Anguillidae Clupeidae

Engraulidae Salmonidae Zeidae Gadidae

Length range (cm) 19–34 6–69 36–163 24–125 34–127 [2] 26–26 29–54 17–100 11–94 25 8–69 67–76 (6–76) [3] 16–45 5–32.5 6–25 3–15 5–9 6–19 26 10–33 8–105 10–37 4–44

Trans. Suffolk Nat. Soc. 56 (2020)

Suffolk Natural History, Vol. 56

Table 2 cont. Family

Scientific name

Common name

Gadidae

Pollachius virens Trisopterus esmarkii Trisopterus luscus Trisopterus minutus Ciliata mustela Ciliata septentrionalis Enchelyopus cimbrius [Gaidropsarus macrophthalmus] Gaidropsarus vulgaris Scomber scombrus Entelurus aequoreus Syngnathus acus Syngnathus rostellatus Syngnathus spp. Syngnathidae (indet.) Aphia minuta Crystallogobius linearis Gobius niger Gobius paganellus Pomatoschistus lozanoi Pomatoschistus minutus Pomatoschistus spp. Gobiidae (indet.) Lepidorhombus whiffiagonis Phrynorhombus norvegicus Scophthalmus maximus Scophthalmus rhombus Zeugopterus punctatus Arnoglossus laterna Hippoglossoides platessoides Limanda limanda Microstomus kitt Platichthys flesus Pleuronectes platessa Buglossidium luteum Microchirus variegatus Solea solea

Saithe Norway pout Bib Poor cod Five-bearded rockling Northern rockling Four-bearded rockling

Lotidae

Scombridae Syngnathidae

Gobiidae

Scophthalmidae

Bothidae Pleuronectidae

Soleidae

Trans. Suffolk Nat. Soc. 56 (2020)

Big-eye rockling [4] Three-bearded rockling Atlantic mackerel Snake pipefish Greater pipefish Nilssen’s pipefish Pipefish (indet.) Pipefish (indet.) Transparent goby Crystal goby Black goby Rock goby Lozano’s goby Sand goby Sand gobies (indet.) Goby (indet.) Megrim Norwegian topknot Turbot Brill Common topknot Scaldfish Long-rough dab Dab Lemon sole Flounder Plaice Solenette Thickback sole Common sole

Length range (cm) 26 6–16 5–36 3–24 7–25 7–13 8–23 24 6–19 8–46 38–45 13–33 13 9–14 12 4 3–5 7–11 6–8 3–6 3–7 2–8 4–6 24 8–15 [2] 24–52 21–55 7 5–15 (5–19) [2] 11–22 3–32 5–37 22–39 3–49 3–14 11–14 6–35

MARINE FISH Table 2 cont.

Length range (cm)

Family

Scientific name

Common name

Carangidae Belonidae Blennidae Lophiidae Moronidae Sparidae Mullidae Labridae Pholidae Ammodytidae

Trachurus trachurus Belone belone Blennius ocellaris Lophius piscatorius Dicentrarchus labrax Spondyliosoma cantharus Mullus surmuletus Symphodus melops Pholis gunnellus Ammodytes marinus Ammodytes tobianus Ammodytes spp.

Horse mackerel Garfish Butterfly blenny Anglerfish Seabass Black seabream Striped red mullet Corkwing wrasse Butterfish Common sandeel Lesser sandeel Sandeel (Indet.)

3–32 40 7 27–46 26–75 18 9–30 9 9–20 5–21 5–25 5–16

Gymnammodytes semisquamatus Hyperoplus immaculatus Hyperoplus lanceolatus Ammodytidae (indet.) Echiichthys vipera Trachinus draco Callionymus lyra Callionymus maculatus Callionymus reticulatus Helicolenus dactylopterus Chelidonichthys cuculus Chelidonichthys lucerna Eutrigla gurnardus Myoxocephalus scorpius Taurulus bubalis Agonus cataphractus Liparis liparis Liparis montagui

Smooth sandeels Immaculate sandeel Greater sandeel Sandeel (Indet.) Lesser weever Greater weever Common dragonet Spotted dragonet Reticulated dragonet Blue-mouth redfish Red gurnard Tub gurnard Grey gurnard Bullrout Sea scorpion Pogge Seasnail Montagu’s seasnail

17–18 14–20 5–36 6 4–18 28 3–28 6–11 7–10 14–18 13–43 5–56 8–39 4–26 7–23 3–16 6–15 7–10

Trachinidae Callionymidae

Sebastidae Triglidae

Cottidae Agonidae Liparidae

Notes: [1] Some participating surveys are considered to confound data for tope and starry smooth-hound [2] The upper size limit reported here is slightly higher than the maximum length normally reported and should be viewed with caution [3] The nominal presence of a 6 cm European eel is viewed with caution [4] Big-eye rockling occurs on the outer continental shelf and this record is considered erroneous, possibly being based on a misidentification or coding error

Trans. Suffolk Nat. Soc. 56 (2020)

Scientific name L. fluviatilis S. canicula G. galeus M. asterias S. acanthias A. radiata L. naevus R. brachyura R. clavata R. microocellata R. montagui A. anguilla A. fallax C. harengus S. pilchardus S. sprattus Clupeidae E. encrasicolus S. trutta Z. faber G. morhua M. aeglefinus M. merlangus P. virens T. esmarkii T. luscus T. minutus C. mustela C. septentrionalis

Trans. Suffolk Nat. Soc. 56 (2020)

15.0 546.0

163.0

884.0

2017

144.0 4.0 34.0 154.0 98.0 -

1400.0

34.0 320.0

220.0

1691.0

2019

107.0 62.0 2.0 18.0 8.0 26.0 5769.6 40099.0 4255.0 3289.0 12.0 44.0 52.0 38326.2 174541.0 42714.0 63727.0 74.0 39.0 157.0 265.0 6.0 79.0 31.0 24.0 42.0 2.0 18304.8 52532.0 13456.0 16012.6 4.0 315.0 128.0 269.0 652.0 322.8 70.0 262.0 344.0 50.7 30.0 18.0 26.0 5.0 2.0 2.0 34.0

2016 2.1 2443.8 467.4 2.0 8.0 122.6 28.5

Q1 2018

1134.0 16.0 178.0

2016

2.0 4.0 4.0 18.0 215.0 640.0 2.0 50.0 24.0 4.0 4.0 4.0 4661.8 17915.8 136.0 4.0 69436.5 111922.1 538.0 2.0 6.0 26.0 8.0 22.0 4.0 21589.0 36136.2 3.0 235.0 44.0 225.0 162.0 28.0 6.0 -

1531.0 2.0 330.0

2020

64.0

12.0 198.3

13.9 2.0 3197.5 3495.8 80.0 76.0 35610.3 222451.2 3673.7 1.9 4.0 6.0 64.0 20.3 75483.4 78722.6 6.0 44.0 68.3 228.1 59.9 411.7 2.0 2.1 -

54.0

8.0 49.4

2017 3.9 1051.2 8.0 381.1

718.6 12.0 108.1 2.0

2019 -

787.8 47.6 178.0 1.9 2.4

2020

2.0 6.0 2.0 112.1 70.7 66.0 12.3 2.0 2.0 63732.8 53271.5 108.0 458.0 268019.8 34574.9 42.0 1422.5 8.1 8.4 28.2 12.8 162.0 8.4 49814.8 168989.0 1777.1 42.4 398.8 277.6 -

Q3 2018 4.0 2281.3 57.6 562.4

Total 10.1 13922.7 143.2 2732.1 9.9 2.4 8.0 141.0 2428.2 2.0 565.8 6.0 79.9 199687.7 970.0 1061322.9 3673.7 2543.4 2.0 34.5 335.3 198.4 531040.3 3.0 54.0 3758.9 2533.9 156.8 49.0

Table 3. Numbers of fish (after all catches standardised to numbers per hour) in Roundfish Area 5 (south-western North Sea) in the IBTS-Q1 and IBTS-Q3 by year (2016–2020).

42 Suffolk Natural History, Vol. 56

Scientific name E. cimbrius G. vulgaris S. scombrus E. aequoreus S. acus S. rostellatus Syngnathus spp. Syngnathidae (indet.) A. minuta C. linearis G. niger G. paganellus P. lozanoi P. minutus Pomatoschistus spp. Gobiidae (indet.) L. whiffiagonis P. norvegicus S. maximus S. rhombus Z. punctatus A. laterna H. platessoides L. limanda M. kitt P. flesus P. platessa B. luteum M. variegatus S. solea T. trachurus

61.0 107.7

9770.4 114.9 10.5 6567.1 145.9

10.0

4.0

6.0 42.0 23.0 -

4.5 -

2016 6.0 12.0 76.3 2.0 -

Q1 Q3 2017 2018 2019 2020 2016 2017 2018 2019 2020 12.0 45.0 100.0 86.0 234.0 434.8 160.1 278.0 606.0 2.0 6.0 373.0 4.0 985.0 1710.2 4265.9 2734.2 6013.0 3130.8 2.0 2.0 2.0 4.0 2.0 2.0 6.0 2.0 4.0 10.0 1.9 2.0 8.0 2.0 4.0 55.0 3.0 13.0 4.0 6.0 64.0 11.0 14.0 3.9 16.0 4.8 2.0 6.0 2.0 4.1 5.0 6.0 4.0 8.0 8.0 8.0 8.0 18.1 8.0 2.0 2.0 2.0 6.0 2.0 8.0 6.0 5.9 2.0 51.0 7.0 47.0 28.0 42.0 350.0 100.0 60.0 107.6 4.0 2.0 2.0 8.0 16.0 4.0 6.0 10294.0 4906.0 7435.0 4702.0 16942.9 25752.7 14615.6 12567.8 20796.5 37.0 59.0 173.0 97.0 92.0 190.0 665.7 78.6 186.0 26.0 21.0 22.0 18.0 4.0 2156.0 1211.0 1774.0 977.0 1288.0 1932.1 984.3 796.8 884.6 881.0 170.0 353.0 312.0 296.0 1026.3 372.3 134.3 125.4 4.0 2.0 243.0 76.0 603.0 201.0 310.0 96.4 788.6 56.1 108.0 2054.0 3.0 42.0 47.0 4082.8 12111.3 18539.6 5290.7 19771.3 Total 1962.0 20.0 19292.5 4.0 10.0 2.0 6.0 2.0 4.0 11.9 14.5 6.0 55.0 26.0 161.7 23.0 2.0 12.1 73.1 37.9 2.0 802.6 42.0 127782.8 1693.2 101.5 18571.0 3816.1 6.0 2543.1 62049.2

MARINE FISH 43

Trans. Suffolk Nat. Soc. 56 (2020)

Ammodytidae (indet.) E. vipera T. draco C. lyra C. maculatus C. reticulatus H. dactylopterus C. cuculus C. lucerna E. gurnardus M. scorpius T. bubalis A. cataphractus L. liparis L. montagui

Scientific name B. belone B. ocellaris L. piscatorius D. labrax S. cantharus M. surmuletus S. melops P. gunnellus A. marinus A. tobianus Ammodytes spp. G. semisquamatus H. immaculatus H. lanceolatus

29.9

4.0 22.0

39.2

2.0

2.0 42.0

933.3 4.0 125.3 4.0 27.9 2330.3 269.4 102.2 85.8 14.3 2.0 -

2016 -

2.0 6.0 871.0 77.0 4.0 196.0

63.0

397.0

22.0 2.0 46.0 2.0 23.0 348.0 4.0 148.0

2017

516.0

2.0 6.0 8.0 267.0 2.0 26.0 36.0 4.0 36.0

2019

111.0 6.0 4.0 4.0 12.0 60.0 1808.0 1150.0 105.0 116.0 4.0 2.0 133.0 510.0 70.0 28.0 47.0

266.0

16.0

11.0 4.0 -

10.0 -

18.0

28.0

Q1 2018

44.0 2.0 5.0 16.0 289.0 213.0 2.0 91.0 2.0 4.0 -

1658.0

2.0 159.0 184.0

2.0 158.0 16.0 -

2020

50.0

6.0 14.0 1044.0 40.0

78.0

1321.5

266.0

2.0 6.0

174.0

2016 2.0 -

2.0 853.4 121.8 12.0 12.0 2450.0 70.0 85.8

1.9 163.9 16.0 50.0 4.0 2896.7

2017

133.6 4.3 -

12.4 4.0 2408.2 102.1

205.0

2206.2

2033.6

83.4 52.0

128.1

Q3 2018

2.1

6.0 14.1 2341.7 4.0

38.1

1840.0

10.0 2.0 396.2

607.8

2.1

2019

27.6 20.4 12.0 3700.8 2.4 12.4 8.4

165.8 2.0

2264.0

5986.0

62.4

576.9

4.0 6.0

2020

2.0 12255.4 4.0 998.9 10.0 4.0 27.6 83.8 166.0 18393.1 999.0 126.6 1295.6 118.6 6.0

Total 2.0 2.0 14.0 268.0 2.0 1999.8 2.0 162.6 221.4 401.0 30.0 4.0 163.0 11992.4

Table 3 (cont.). Numbers of fish (after all catches standardised to numbers per hour) in Roundfish Area 5 (south-western North Sea) in the IBTS-Q1 and IBTS-Q3 by year (2016–2020).

44 Suffolk Natural History, Vol. 56

MARINE FISH

Table 4. Frequency of occurrence (% of trawl stations in which the species was reported) of fish from scientific trawl surveys in Roundfish Area 5 in Q1 and Q3 (2016– 2020, years combined) and for all data combined. Only those species for which the frequency of occurrence was ≥10% in either Q1 or Q3 shown. Species Limanda limanda Merlangius merlangus Pleuronectes platessa Sprattus sprattus Clupea harengus Scyliorhinus canicula Eutrigla gurnardus Echiichthys vipera Callionymus lyra Buglossidium luteum Microstomus kitt Raja clavata Solea solea Agonus cataphractus Mullus surmuletus Mustelus asterias Trachurus trachurus Myoxocephalus scorpius Raja montagui Hyperoplus lanceolatus Scomber scombrus Trisopterus luscus Gadus morhua Trisopterus minutus Engraulis encrasicolus Arnoglossus laterna Chelidonichthys lucerna Ciliata mustela Pomatoschistus Raja brachyura Enchelyopus cimbrius Scophthalmus maximus Alosa fallax Sardina pilchardus Dicentrarchus labrax Platichthys flesus Galeorhinus galeus Chelidonichthys cuculus Pholis gunnellus Scophthalmus rhombus Ammodytes tobianus Ammodytes marinus Melanogrammus aeglefinus

All

99.0% 99.0% 96.0% 99.0% 84.2% 67.3% 68.3% 65.3% 52.5% 53.5% 48.5% 56.4% 56.4% 60.4% 29.7% 34.7% 25.7% 52.5% 38.6% 28.7% 6.9% 46.5% 43.6% 39.6% 45.5% 25.7% 17.8% 32.7% 23.8% 17.8% 16.8% 9.9% 14.9% 10.9% 15.8% 15.8% 1.0% 6.9% 7.9% 5.0% 13.9% 5.0% 4.0%

100.0% 98.6% 94.4% 71.8% 81.7% 90.1% 85.9% 83.1% 74.6% 60.6% 64.8% 50.7% 47.9% 31.0% 74.6% 60.6% 69.0% 26.8% 43.7% 54.9% 83.1% 22.5% 26.8% 31.0% 11.3% 35.2% 25.4% 2.8% 9.9% 18.3% 15.5% 22.5% 12.7% 14.1% 5.6% 2.8% 23.9% 14.1% 12.7% 14.1% 0.0% 12.7% 12.7%

99.4% 98.8% 95.3% 87.8% 83.1% 76.7% 75.6% 72.7% 61.6% 56.4% 55.2% 54.1% 52.9% 48.3% 48.3% 45.3% 43.6% 41.9% 40.7% 39.5% 38.4% 36.6% 36.6% 36.0% 31.4% 29.7% 20.9% 20.3% 18.0% 18.0% 16.3% 15.1% 14.0% 12.2% 11.6% 10.5% 10.5% 9.9% 9.9% 8.7% 8.1% 8.1% 7.6%

Trans. Suffolk Nat. Soc. 56 (2020)

Suffolk Natural History, Vol. 56

Trans. Suffolk Nat. Soc. 56 (2020)

Pogge Agonus cataphractus, a northerly species, was reported more frequently in the south-western North Sea during Quarter 1 surveys than in Quarter 3.

J. Ellis

Seasonality Species found proportionately more frequently in Q1 (January–March) than Q3 (July–September) across the study period (Table 4) included sprat, bib, anchovy, pogge Agonus cataphractus, bullrout (or short-spined sea scorpion) Myoxocephalus scorpius, Atlantic cod Gadus morhua, European seabass Dicent -rarchus labrax, five-bearded rockling Ciliata mustela and flounder Platichthys flesus. For example, European seabass was found in 16% of the Q1 trawl catches compared to only 6% of the Q3 catches; flounder in 16% compared to 3%, and Atlantic cod in 44% compared to 27%. Five-bearded rockling was recorded in almost a third of the Q1 hauls, but was only reported occasionally during Q3 (3%). Species found proportionately more frequently in Q3 than Q1 across the study period (Table 4) included mackerel (83% compared to 7%), striped red mullet Mullus surmuletus (75% compared to 30%), lesser-spotted dogfish (90% compared to 68%), horse mackerel, starry smooth-hound, tope Galeorhinus galeus, common dragonet Callionymus lyra, lesser weever, lemon sole Microstomus kitt, grey gurnard and turbot Scophthalmus maximus.

J. Ellis

In terms of the most abundant fish species (Table 3), 17 taxa accounted for >99% of the total number of raised fish numbers. These were dominated by small pelagic fish such as sprat Sprattus sprattus, herring Clupea harengus, unidentified clupeids (e.g. small herring and sprat that were either too small and/or damaged and could not be speciated accurately), anchovy Engraulis encrasicolus, horse mackerel Trachurus trachurus, mackerel Scomber scombrus. The other most abundant species included various gadoids (whiting Merlangius merlangus and bib Trisopterus luscus), flatfish (dab Limanda limanda, plaice Pleuronectes platessa, solenette Buglossidium luteum and sole Solea solea), elasmobranchs (lesser-spotted dogfish Scyliorhinus canicula and starry smooth-hound), as well as grey gurnard Eutrigla gurnardus, lesser weever Echiichthys vipera and greater sandeel Hyperoplus lanceolatus.

Starry smooth-hound Mustelus asterias, a southerly species, was reported slightly more frequently in the south-western North Sea during Quarter 3 surveys.

MARINE FISH

Unusual fish records Most of the species reported are relatively well known from the area (Heessen et al., 2015), with some comments on the more interesting records provided below. Small-eyed ray Raja microocellata: One specimen, measuring 25 cm, was recorded in 2020-Q1 at a depth of almost 50 m east of Great Yarmouth (52.60°N, 2.46°E). This species is more common in the Bristol Channel and English Channel, and is generally infrequent in the North Sea. John dory Zeus faber: Seventeen individuals (10–33 cm length) were recorded, three in 2016 (Q1), three in 2017 (Q3), four in 2019 (Q3) and seven in 2020 (Q1 and Q3). These specimens were found at depths of 31–45 m off the Norfolk coast in the area of 51.25–53.56°N to 1.71–2.86°E. Butterfly blenny Blennius ocellaris: One specimen, measuring 7 cm, was reported in 2019-Q1 at a depth of 40 m off the Kent coast east of Ramsgate (51.30°N, 1.74°E). Black seabream Spondyliosoma cantharus: One specimen, measuring 18 cm, was reported in 2017-Q1 at a depth of 42 m off the Suffolk coast approximately 50 km east of Southwold (52.25°N, 2.35° E). Corkwing wrasse Symphodus melops: One specimen, measuring 9 cm, was found in 2019-Q1 at a depth of 43 m approximately 60 km off the Essex coast, east of Southend-on-Sea (51.56°N, 1.75°E). Greater weever Trachinus draco: One specimen, measuring 28 cm, was found in 2016Q1 (53.75°N, 2.77°E; 31 m depth). Blue-mouth redfish Helicolenus dactylopterus: Twelve individuals (14–18 cm) were reported from two hauls in 2020-Q3 (53.46°N, 1.06°E and 53.50°N, 0.68°E). They were caught offshore from Grimsby. Discussion Trawl surveys are not representative of all the fish species present in an area, and this relates to a variety of reasons. For example, small bodied fish can pass through the meshes of the trawl, some fish species are only found in very shallow or rocky habitats that are not sampled during trawl surveys, and other species may escape the trawl if they are large-bodied and/or fast swimming species. This leads to the number of fish species described in trawl surveys being much lower than the total fish diversity. For example, Yang (1982a,b) reported 224 fish species from the wider North Sea area, and more species have been recorded since then (e.g. Stevens et al., 2004; Ellis, 2007). Whilst there are no up-to-date, published inventories of the ichthyofauna of the North Sea, it should also be recognised that regional lists are also lacking for many areas, with no contemporary ichthyofaunal lists for either Suffolk or the wider coastal waters of East Anglia. Future research could usefully update such information, thus augmenting the information provided in the earlier accounts of Paget & Paget (1834), Trans. Suffolk Nat. Soc. 56 (2020)

Suffolk Natural History, Vol. 56

Laver (1898), Murie (1903), Patterson (1910), Collings (1933) and Wheeler (1979). Additional information on the fishes of the area have also been included in a range of other accounts (e.g. Rogers et al., 1998; Ellis, 2004, 2010; Ellis & Eade, 2007; Broad, 2019). Among the unusual fish species reported here was a single specimen of greater weever. Ellis (2012) noted that this species was considered to be relatively common in the southern North Sea in the first half of the 20th century, but there have been very few records in recent decades. Indeed, the IBTS survey had not recorded any individuals off the East Anglian coast in the past three decades, although a mature female was caught by an Orford-based fishing vessel off the Suffolk coast in 2012 (Ellis, 2012). Several specimens of blue-mouth redfish were caught east of Grimsby in 2020. Reports of this Atlantic species from the North Sea have been sporadic, as it occurs normally on the outer continental shelf and along the shelf edge on the Atlantic coasts of western Europe and Mediterranean Sea (Heessen et al., 1996, 2015). Heessen et al. (1996) described how blue-mouth redfish ‘invaded’ the North Sea during the winter of 1990/91 and then spread across a broader areas of the North Sea in successive years, before declining. It appears that there may have been a similar event in recent years. The comparison of historical and contemporary information can help understand longer-term changes in fish biodiversity. For example, several studies have highlighted longer-term declines in some elasmobranch fish in the North Sea (e.g. Philippart, 1998; Wolff, 2000; Sguotti et al., 2016). Nevertheless, several species of sharks and rays were commonly sampled in the trawl surveys, including lesser-spotted dogfish, starry smooth-hound, thornback ray Raja clavata and spotted ray Raja montagui. It is clear that some northerly (boreal) species such as bullrout, pogge, fivebearded rockling and cod were recorded more frequently in the cooler part of the year (Q1), as well as other species such as sprat and seabass. Species that were observed more frequently in the summer included several that have a more southerly biogeographic affinity (Yang, 1982b), including striped red mullet, starry smoothhound, tope, lesser-spotted dogfish, lesser weever and turbot. The data considered here contained some suspicious records, one likely erroneous identification or coding error, and some records that appeared to be slightly larger than the typical length range. As has been pointed out earlier (Daan, 2001; ICES, 2007), there are potential data quality issues in databases of trawl survey data, thus highlighting that there is a need for continued quality assurance of the data, especially for families such as the gobies (Gobiidae), sandeels (Ammodytidae) and various other families of non-commercial fish. Whilst the larger, commercially-important fish species occurring off the coast of East Anglia is well known, there is more uncertainty in relation to some of the smallerbodied, non-commercial species. Consequently, authenticated records of such species could usefully be better documented, including through the potential use of maintaining regional reference collections in relevant museums.

Trans. Suffolk Nat. Soc. 56 (2020)

MARINE FISH

References Broad, G. (2019). Marine Recorders Report Trans. Suffolk Nat. Soc., 55: 43–48. Collings, D. W. (1933). The fishes of Suffolk. Trans. Suffolk Nat. Soc., 2: 104–133. Daan, N. (2001). The IBTS database: a plea for quality control. ICES CM 2001/T:03, 19 pp. Ellis, J. R. (2004). The occurrence of thresher shark off the Suffolk coast. Trans. Suffolk Nat. Soc., 40: 73–80. Ellis, J. R. (2007). Occurrence of pelagic stingray Pteroplatytrygon violacea (Bonaparte, 1832) in the North Sea. Journal of Fish Biology, 71: 933–937. Ellis, J. R. (2010). Blackfish Centrolophus niger (Centrolophidae) off the Suffolk coast. Trans. Suffolk Nat. Soc., 46: 6–9. Ellis, J. R. (2012). Notes on unusual fish off the Suffolk coast: Atlantic bonito Sarda sarda and greater weever Trachinus draco. Trans. Suffolk Nat. Soc., 48: 79–82. Ellis, J. R. & Eade, M. (2007). Bogue (Boops boops) in the southern North Sea. Trans. Suffolk Nat. Soc., 43: 72–74. Farrell, E. D., Clarke, M. W. & Mariani, S. (2009). A simple genetic identification method for Northeast Atlantic smoothhound sharks (Mustelus spp.). ICES Journal of Marine Science, 66: 561–565. Heessen, H. J. L., Daan, N. & Ellis, J. R. (Eds.) (2015). Fish atlas of the Celtic Sea, North Sea, and Baltic Sea. Wageningen Academic Publishers / KNNV Publishing, 572 pp. Heessen, H. J., Hislop, J. R. & Boon, T. W. (1996). An invasion of the North Sea by bluemouth, Helicolenus dactylopterus (Pisces, Scorpaenidae). ICES Journal of Marine Science, 53: 874–877. ICES (2007). Report of the Workshop on Taxonomic Quality Issues in the DATRAS Database (WKTQD), 23–25 January 2007, ICES, Copenhagen. ICES CM 2007/ RMC:10; 45 pp. ICES (2015). Manual for the International Bottom Trawl Surveys. Series of ICES Survey Protocols SISP 10 ‐ IBTS IX; 86 pp. Laver, H. (1898). The mammals, reptiles and fishes of Essex. Essex Field Club Special Memoirs, 3: 138 pp. Murie, J. (1903). Report on the sea fisheries and fishing industries on the Thames Estuary. Kent and Essex Sea Fisheries Committee. Waterlow Bros. & Layton (London), 250 pp. Paget, C. J. & Paget, J. (1834). Sketch of the natural history of Yarmouth and its neighbourhood. Longman, Rees & Co. (London), xxxii + 88 pp. Patterson, A. H. (1910). Rough notes on the fish and fisheries of East Suffolk. John Buckle, Great Yarmouth. Philippart, C. J. (1998). Long-term impact of bottom fisheries on several by-catch species of demersal fish and benthic invertebrates in the south-eastern North Sea. ICES Journal of Marine Science, 55: 342–352. Rogers, S. I., Millner, R. S. & Mead, T. A. (1998). The distribution and abundance of young fish on the east and south coast of England (1981 to 1997). CEFAS (Lowestoft), Science Series Technical Report, 108: 130 pp.

Trans. Suffolk Nat. Soc. 56 (2020)

Suffolk Natural History, Vol. 56

Sguotti, C., Lynam, C. P., García-Carreras, B., Ellis, J. R. & Engelhard, G. H. (2016). The distribution of skates and sharks in the North Sea: 112 years of change. Global Change Biology, 22: 2729–2743. Stevens, M., Rappé, G., Maes, J., Van Asten, B. & Ollevier, F. (2004). Micropogonias undulatus (L.), another exotic arrival in European waters. Journal of Fish Biology, 64: 1143–1146. Wheeler, A. C. (1979). The tidal Thames: the history of a river and its fishes. Routledge & Kegan Paul Books. Wolff, W. J. (2000). The south-eastern North Sea: losses of vertebrate fauna during the past 2000 years. Biological Conservation, 95: 209–217. Yang, J. (1982a). An estimate of the fish biomass in the North Sea. Journal du Conseil International pour l’Exploration de la Mer, 40: 161–172. Yang, J. (1982b). The dominant fish fauna in the North Sea and its determination. Journal of Fish Biology, 20: 635–643. G. Broad 1 Plane Tree House The Causeway Peasenhall Suffolk IP17 2HU J. R. Ellis CEFAS, Lowestoft Laboratory Pakefield Road Lowestoft Suffolk NR33 0HT

Trans. Suffolk Nat. Soc. 56 (2020)