Sophie Elliott 1*, Bill Turrell 2, Mike Heath 3 and David Bailey 1 University of Glasgow 1, Marine Scotland Science 2, University of Strathclyde 3 The Effect of Fine Scale Habitat Characteristics on the Populations Density of Juvenile Gadoid Fishes : Acknowledgments and funding: COAST, Millport FSC and Bailey research group

Background Research Questions Does the availability of important habitats affect recruitment success? Should certain habitats be protected to improve recruitment success? Decline in demersal fish stocks Lack of recovery Little understanding of gadoid nursery areas McIntryre et al, 2012 Gadus morhua Melanogrammus aeglefinus Merlangius merlangus Stereo Baited Remote Underwater Video cameras Event measure software (record MaxN and size measurements) Variety of different habitats and abiotic conditionsMethod Within the Firth of Clyde - South Arran Nature Conservation MPA Study Area

Results Linear model, p<0.001 Haddock length ~ Julian date Linear model, p<0.001 Cod length ~ Julian date + Depth + Wave fetch + Depth * Wave fetch Length Change Relative Abundance * * ** *** Negative binomial model p<0.001 Cod MaxN~ Habitat type + Julian date+ Depth + Wave fetch * *** + Negative binomial model p<0.001 Haddock MaxN~ Habitat type + Julian date+ Depth + Richness + + ** *** ** * Conclusions A significant difference in relative abundance of juvenile cod was seen between habitat type A decrease in cod and whiting was seen over the summer period although pulse recruitment is occurring Habitat had no effect on the relative abundance of haddock and whiting An increase in size of individuals was seen in over the summer in all three species Zero inflated Poisson model p<0.01 Whiting MaxN~ Richness + Julian date * ** Strengthen the data set and compare to year one Collect data within a broader depth range Looking at behavioural changes within habitats (such as shoaling as an antipredator technique) Otolith analysis to age fish Next Steps Linear model, p<0.01 Whiting length ~ Julian date + Depth