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Sampling for anadromous shad in IrishSACs – “needle in a haystack” orstatistical repeatability?James King, Sean Rooney, Nicola O’ GormanInland Fisheries Irelandjimmy.king@fisheriesireland.ie

The ShadsAlosa alosaAlosa fallaxTwaiteshad onthe Barrowat St.Mullins

Special Areas of Conservation for Twaite shad in Republic of Ireland

R. Barrow SAC: top of the tide at St. Mullins weirLocation of:• smelt spawning•Shad spawning• adjacent Corbicula fluminea infestation

R. Barrow estuary at Suir-Barrow confluence

Suir estuary at Waterford city

R. Suir: Shad spawning at Carrick-on-Suir – tidal freshwater, 53 km from open sea

Munster Blackwater: top of the tide at Cappoquin – shad and smelt spawning

Munster Blackwater estuary – lower reaches

Shad length frequency distribution in four Irish SACsNo. fish8070605040302010Hybrid (n=7)Twaite (n=411)Allis (n=40)0+ autumn 2+ springAngling + Commercial netsmen060 100 140 180 220 260 300 340 380 420 460 500 540 580Length mmFrom: King and Roche 2008 (Hydrobiologia 602:145-154)

Sampling for adult migrating fish(April – June)• Artisanal netsmen• Drift netting• Angling• Evidence at spawning locations• Attributes of spawning locations

R. Barrow estuary: Drift net sampling for adult Alosa, 5.2005

Drift net sampling – May 20055No. fish432MBW (n=2+Suir (n=1)Barrow (n=16)10300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500Length mm

Angling for Twaite shad:

Size range of rod-caught shad18161412Barrow angling (n=50)MBW angling (n=28)Suir angling (n=10)No. fish1086420300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500Length mm

Angling for shad at St. Mullins, R. Barrow:Irish Specimen Fish Committee and Shad conservation

1.41.2Qualifying specimen weight (kg1700.86050403020Number of specimen fish1001978198019821984198619881990199219941996199820002002200420062008Year of captureFig. 1. Numbers of rod caught specimen twaite shad. Solidline represents annual qualifying specimen weight.Genetics ‘hiatus’ – Coscia et al 2010 J. Fish Biol.0.60.40.20

Spawning habitat surveys

R. Barrow: Velocity distribution acrosstransect at spawning location, low tideTransect 41.21Velocity (m/sec)0.80.60.40.2Subsurface0.5m DepthBenthic010 20 30 40 50Distance from LHS (m)

Bed conditions:Spawning ground

Sampling for 0-group fish• Egg sampling• Bongo netting (plankton sampling)• Autumn sampling for young-of-year

Bongo netting for shad post-larvae:R. Barrow, June & July 2011?

Juvenile shad?R. Barrow 6.2010JuvenileAlosa alosavia PeterBeek(Rhine,Germany)

Juvenile shad R. BarrowJune & July 2011:Fin ray countsconsistent withWheeler (1978)Dorsal finAnal finJuvenileAlosa alosavia PeterBeek(Rhine,Germany)

Post-larval shad survey 201135R. Barrow June - July 2011302520% July (n=70)% June (n=103)%15105010121416182022242628303234363840Length mm

‘Micro shad’Bongo netting:June – July 2011No. shad/m 3 water(Range: 0 – 6.29)

Estuary pair-trawling for juvenile shad and smelt – October

Juvenile shad (0+ age), R. Barrow estuary, 10. 2005

Autumn-caught juvenile shad, October 2005108CPUE(No/30 min. trawl):No. fish64Suir (n = 2)Barrow (n = 15)Barrow: 7.5Suir: 1.02010 20 30 40 50 60 70 80 90 100 110Length mm

Allis in Wonderland: marine-caught shadsA source of information on status????

Shad off Irish coast – what do we know?16No. fish14121086SW coast 200 km 7.2011(n=26)S coast 12 mile limit 6.2001(n=70)420250270290310330350370390410430450470490510530550Length mm