The potential of shoreface nourishments for habitat enhancement A - PowerPoint PPT Presentation

The potential of shoreface nourishments for habitat enhancement A case of the Sand Engine lagoon as a nursery for juvenile plaice ( Pleuronectes platessa L.) Lotte Meeuwissen, Ralf van Hal, Lorna Teal, Marjolein Post

Sand engine; mega nourishment 2011 21.5 Mm 3 128 ha sand 1.5 km 2 km Shallow artificial lagoon Lagoon The Netherlands: Ter Heijde Lagoon Lagoon Pilot project for sustainable coastal protection

Over time… Lagoon Lagoon Lagoon October 13, 2011 May 14 , 2012 July 1 , 2013 Lagoon as nursery area?

Plaice ( Pleuronectes platessa L.) § Dutch shallow coastal area as nursery area ● Entering larvae (0-group): March and April § Changing habitat requirements ● Increasing length à More coarse sand and lower temperatures § Spatial distribution pattern change during life cycle ● Increasing length à Optimal temperature and tolerance range 0.15 10 cm Growth (cm day -1 ) 0.10 25 cm 0.05 40 cm 0.00 0 5 10 15 20 25 30 Temperature ( ° C) (Teal et al. , 2010) Temperature ( ° C)

Effect of nourishment on coast SEA WATER HIGHER SHALLOW TEMPERATURE GROWTH WATERS RISES Habitat enhancement

Material and Methods; fieldwork Every 2 weeks: 2 m beam trawl 2012: end of April – end of Mesh size: 1 and 2 cm August 2013: mid May – mid August Depth: 1.5-3 m and 4-5 m 1-3 trawls Numbers and length of 0-group plaice à predominant flatfish species Distance and time Temperature

Material and Methods; nursery quality § Numbers in m 2 § Growth in mm per day § Estimates of growth potential Comparing predicted and observed growth: Dynamic Energy Budget (DEB) modelling (ad lib.) (Van der Veer, 2009; Teal et al., 2012) Growth and DEB: only lagoon and area South 2012 compared

Results; numbers 2012: Density lagoon increased, peak end of May, decrease till the end Density North and South 0 at beginning, later low 2013: Density lagoon decreasing Plaice present in North and South Density lower in all areas in 2013 Difference in axes!

Results; length 2012: Smallest plaice in lagoon Biggest plaice in South 2013: Bigger plaice in additional areas. At the beginning plaice in lagoon bigger than in 2012 Smaller sizes in 2013 than in 2012

Results; growth Lagoon: Peak in growth rate South: Increasing growth rate

Results; Dynamic Energy Budget Model Lagoon: Observed growth lower than predicted growth South: Observed and predicted growth more equal

Discussion; numbers § Lagoon suitable habitat for flatfish ● Mainly plaice § Lagoon increased attraction in 2012 ● Fluctuation in larvae supply Determined by year-specific abiotic and biotic conditions ● Changing morphology

Discussion; growth § Similar growth pattern found in Balgzand 1975-1988 and 1990-2002 (north-eastern North Sea) and Ems estuary Wadden Sea 1992 (Teal et al. , 2008, Jager et al. , 1995) § Lower growth rates due to food limitation ● Supported by DEB ● Lagoon nearly a closed system § Outer areas harbour better growth conditions

Habitat enhancement with nourishment? § Lagoon temporary nursery area ● Only in 2012 habitat enhancement due to design Sand Engine § Size of the Sand Engine § Species specific habitat preferences

Questions? Many thanks to: Adriaan Rijnsdorp Shore Symposium Meeuwissen, L., van Hal, R., Teal, L., Post, M.H.M., 2017, Journal of Sea Research, In review The potential of shoreface nourishments for habitat enhancement: a case of the Sand Engine lagoon as a nursery for juvenile plaice ( Pleuronectes platessa L.) Contact: lottemeeuwissen@live.nl Still looking for a job ;-)

Total numbers per species caught per sampled area in 2012 and 2013. Species Lagoon South North Far South 2012 2013 2012 2013 2012 2013 2013 Plaice (Pleuronectes platessa) 325 84 52 113 12 12 49 Sole (Solea solea) - - 4 1 1 4 1 Turbot (Scophthalmus maximus) - - 5 6 3 5 5 Dab (Limanda limanda) 1 - 3 5 - 3 3 Common shrimp (Crangon crangon) 459 95 304 5795 711 7833 5888 Goby species (Pomatoschistus species) 100 35 94 395 34 188 5336 Sprat (Sprattus sprattus) 6 3 33 - 17 1 4 16

July 2017

Temperature The average seawater surface temperature (°C) of the trawls for every date in each sampling area in 2012 (solid black lines) and 2013 (grey dotted lines).

The number of performed trawls per sampling area per day with corresponding depth and used mesh size of the beam trawl in 2012. Sampling Mesh Depth 24- 2- 23- 7- 20- 26- 27- 10- 29- area size April May May June June June July Aug Aug Lagoon 1 cm 1.5-3 m 1 2 1 1 - - - - - 1 cm 4-5 m 1 1 1 - - - - - - South 1 cm 1.5-3 m 1 2 2 2 1 - - - - 1 cm 4-5 m 1 2 2 2 1 - - - - North 1 cm 1.5-3 m 1 1 2 2 1 - - - 1 cm 3.5-4.5 - 1 - - - - - - - Lagoon 2 cm 1.5-3.5 m - - - 2 2 1 1 2 5 2 cm 3-4 m - - - - 1 - - - 3 2 cm 4-5 m - - - 1 - 1 1 2 2 South 2 cm 1.5-3.5 m - - - - 2 3 2 3 - 2 cm 4-5.5 m - - - - 1 2 2 2 - North 2 cm 1.5-3.5 m - - - - 1 1 2 1 - 2 cm 3.5-4.5 m - - - - - 1 - - - Total 5 9 8 10 10 9 8 10 10

The number of performed trawls per sampling area per day with corresponding depth and used mesh size of the beam trawl in 2013. Sampling Mesh size Depth 16-May 28-May 11- 2- 17-July 23-July 20-Aug area June July Lagoon 1 cm 1.5-3 m - - 1 - 2 1 1 1 cm 4-5 m 1 1 - 1 1 1 1 Far south 1 cm 1.5-3 m 1 1 1 1 1 1 1 1 cm 4-5 m 1 1 1 1 1 1 1 South 1 cm 1.5-3 m 1 2 1 1 1 1 1 1 cm 4-5 m 1 1 1 1 1 1 1 North 1 cm 1.5-3 m 1 1 1 1 1 1 1 Lagoon 2 cm 1.5-3 m 1 1 1 1 2 1 1 2 cm 4-5 m 1 1 1 1 1 1 1 Far south 2 cm 1.5-3 m 1 - 1 1 1 1 1 2 cm 4-5 m 1 2 1 1 1 1 1 South 2 cm 1.5-3 m 1 - 1 1 1 1 1 2 cm 4-5 m 1 1 1 1 1 1 1 North 2 cm 1.5-3 m 2 1 1 1 1 1 1 2 cm 4-5 m - 1 - - - - - Total 14 14 13 13 16 14 14

In order to calculate the growth rate per day of the 0-group plaice which had been caught on the first sampling day a reference length of 12 mm at 1 March was used, derived from a research performed in the western Wadden Sea (Van der Veer, 1986). 21

DEB Model 9;<= 1 9: 9: )* +, - ./0 1[3 * ]× 678 &' ṗ " 9 !" !# = &' > ? @[> A ] The effect of temperature on physiological rates in the DEB model is incorporated by multiplying the rates with an enzyme fraction that is in its active state (Kooijman, 2010). This fraction Fr is calculated as: 1 + exp 𝑈 𝑈 IJ' − 𝑈 + exp 𝑈 𝑈 O − 𝑈 HN HN HO HO 𝑈 − 𝑈 𝑈 N 𝑈 IJ' H H 𝐺𝑠 = exp × 1 + exp 𝑈 𝑈 − 𝑈 {𝑈 𝑈 O − 𝑈 𝑈 IJ' 𝑈 HN HN HO HO + exp 𝑈 } 𝑈 N The estimates of parameters of the DEB model for female plaice Pleuronectes platessa at 10°C were used from Van de Veer et al. (2009). All parameters are described in Table 1. For full description of the model see Teal et al., 2012. 22