New in the ICES CM 2006/C:30

Henk J.L. Heessen and Jim R. Ellis

Introduction

In recent years a number of new fish and invertebrate species have been reported from There are several biological responses to variations in environmental conditions (including the North Sea, both from research vessel surveys and from commercial catches. At the climate change), as suggested by Cushing & Dickson (1976), and these include (a) same time the abundance of some more southerly fish species has increased, and in the appearance of vagrant species, (b) establishment of new, resident populations, (c) case of the striped red mullet (Mullus surmuletus) and sea bass (Dicentrarchus labrax), increases/decreases in fish stocks (due to year-class strength), and (d) more fundamental even a directed fishery has developed. Other species are now found in much higher structural changes in the ecosystem and fish assemblage. numbers than some decades ago. Vagrants and regular visitors

Vagrants are species that are only caught incidentally in the North Sea, usually in low numbers, breed in other areas, and do not establish resident populations. Many of the known vagrants in the North Sea are pelagic fish. Some species are observed more regularly, though not every year, and may not have self-sustaining North Sea populations.

Violet stingray (Pteroplatytrygon Butterfish (Stromateus fiatola) is another vagrant and violacea) is a vagrant which is which occurs in the subtropical part of the Eastern Atlantic widespread in tropical and warm and is rare in the . Two specimens (46 and 49 temperate oceanic waters. One cm) were caught by a beam trawler in the Southern Bight specimen of 99 cm was caught off (33F3) in November 2005. north-east England in November 2005.

60.0 61 IBTS q1: bluemouth Bluemouth (Helicolenus 59.5 Thresher shark (Alopias 60 59.0

58.5 59 100 dactylopterus) is a typical species vulpinus) is more commonly 58.0 58 10 57.5 57 along the edge of the continental encountered in oceanic waters, 57.0

56 r 1

u 56.5 o shelf. O- or 1-group fish entered the 55 h though may breed in shallower 56.0 r 0,1 e

54 p 55.5

N 0,01 northern North Sea in the winter of seas. During 2004, several 53 55.0 Blyth

52 White Bank 0,001 1990-91, and gradually spread south- 54.5 Dogger Bank specimens, mostly juveniles, were 51 54.0 0,0001 Silver Pit 50 53.5 1977 1982 1987 1992 1997 2002 eastwards. They were even recorded recorded in the southern North 53.0

-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 Caister Great Yarmouth 52.5 Lowestoft from the Wadden Sea. After 10 years Southwold Sea, and earlier published Aldeburgh 52.0

the last fish from this invasion seem 51.5 information also indicates that this

51.0

to have disappeared. 50.5 species is a regular visitor.

50.0 -2 -1 0 1 2 3 4 5 6 7 8 9

North Sea species

Catches of a number of species that are known to occur and in the North Sea have clearly increased over the last decades. Many of these are traditionally considered as southerly or Lusitanian species.

61 61 IBTS q1: smooth hounds IBTS q1: striped red mullet 61 60 60 60 IBTS q1: solenette 59 59 100 100 59 100 58 58 58 57 10 57 10 57 10 r r 56 56 r

u 1 u u 1 56 o o 55 o h 55 h h 55 r r 0,1 r 0,1 1 e

54 e 54 e p p

p 54 53 N 0,01 53 0,01 N N 53 0,1 52 52 0,001 0,001 52 51 51 0,0001 51 0,01 50 50 0,0001 1977 1982 1987 1992 1997 2002 1977 1982 1987 1992 1997 2002 50 1977 1982 1987 1992 1997 2002 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 Though smooth hounds (Mustelus spp.) are not caught in Striped red mullet (Mullus surmuletus) used to enter the Solenette (Buglossidium luteum) is a small (up to large numbers during IBTS surveys, there has been a gradual southern North Sea in spring via the Channel and return in autumn. 14 cm), a southerly species, mainly occurring in the southern increase in average catches. Such increases have also been Since the 1990's they occur throughout the year and a fishery North Sea. Survey catches increase since the late 1980's. observed in surveys operating in the Celtic Sea. developed in the southern North Sea. Scaldfish (Arnoglossus laterna), another small flatfish, shows a similar pattern (though not shown here).

54.0 References

53.5 Cushing, D.H. and Dickson, R.R. (1976). The biological response in the sea to climate change. Adv. 53.0 Mar. Biol. 14: 1–122. 52.5 Ellis, J.R. (2004). The occurrence of thresher shark off the Suffolk coast. Transactions of the Suffolk Naturalists' Society, 40: 73–80. 52.0 Ellis, J.R. (In prep.). Occurrence of pelagic stingray Pteroplatytrygon violacea (Bonaparte, 1832) in

51.5 the North Sea. Ellis, J.R., Warr, K. and Cooper, K. (In prep.). The occurrence of desmaresti 51.0 0 1 2 3 4 5 (Crustacea: Stomatopoda) off the Suffolk coast. Heessen, H.J.L., Hislop, J.R.G. and Boon T.W. (1996). An invasion of the North Sea by blue-mouth, Mantis shrimp (Rissoides desmaresti) were first recorded in the North Sea in the early 1900's, though Helicolenus dactylopterus (Pisces, Scorpaenidae). ICES J. of Mar. Sci., 53:874–877. there have been few published records since the 1960's. Recent surveys in the southern North Sea have captured adults and stomatopod larvae, indicating that this southerly species has a breeding population in the North Sea. Henk J.L. Heessen, IMARES, IJmuiden, The Netherlands. [email protected] Jim Ellis, CEFAS, Lowestoft, United Kingdom. [email protected]

Wageningen IMARES, Wageningen UR and TNO P.O. Box 68, 1970 AB IJmuiden, The Netherlands have joined forces by housing Tel. +31 255 564 692 their applied marine research e-mail: [email protected] in a newly established institute, www.imares.wur.nl IMARES.

1736- 2006 heessen1