Coastal Fish Habitats in General What are we talking about?

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1 Coastal Fish Habitats in General What are we talking about? Josianne G. Støttrup FISK og FISKERI perspektiv

2 8750 km coastline ~1 km coastline for every 5 km² land High level of land use for agriculture, urbanization, infrastructure Land reclamation (15%, <2 m)

3 Coastal systems are important for fish 75 % of all commercial fish species utilise coastal areas (Chambers 1992) nursery feeding spawning AIM: All fish species should be able to complete life cycle with good growth and survival 3

4 Fish life cycle and needs for different habitats Essential Fish Habitats (EFH) Migratory corridors Coast Water surface Feeding grounds, shelter and natural refuges

5 Essential fish habitats those waters and substrate necessary for fish to spawn, breed, feed and grow to maturity (NMFS 1996) Examples of essential fish habitats in coastal areas Sand banks: nursery areas for flatfish Eelgrass / macrophytes: nursery areas for cod, eel, etc. Stone reefs: refuge for young codfish Biogenic reefs: feeding grounds for flatfish, codfish, etc. 5

6 Seitz et al

7 Soft bottom habitat, sand and muddy sand No epibenthic structure Prey are mobile or infaunal Predators are mobile Appear barren but can be highly productive (> ind/m 2 ) Fra Danmarks Natur

8 Habitat size and recruitment Depth distribution of different 0- group flatfish species Plaice, sole dab Turbot Brill, flounder From Gibson, 1994

9 Habitat size and recruitment for different flatfish species Dab Sole Plaice,Flounder Turbot & brill From van der Veer et al., 2000.

10 Habitat size and recruitment Relation ship between recruitment and size of nursery area for plaice. From Gibson, 1994

11 Some coastal areas with hard bottom, pebbles, stones or stonereefs Hard bottom is necessary for macrophytes and benthic fauna that need to attach themselves for survival. Several fish species are highly affiliated to stone reefs

12 Biodiversity and abundance on structures Invertebrate biodiversity with increasing complexity Macroinvertebrate abundance with increasing vegetation biomass Meager & Schlacher 2013 Heck & Wetstone

13 Biogenic habitats Diversity Enhances recruitment of juveniles Buffers physcial stress Retains food and cycles nutrients and detruitus Provides refuge from predators

14 Eelgrass Higher biodiversity Fra Danmarks Natur

15 Examination of fish community along the Swedish Skagerrak coast in a sandy bottom and eel grass beds Eelgrass 28 species Sand bottom 19 species Gadoids (cod, whiting) Wrasses (læbefisk) Pipefishes (nålefisk) Flatfish (plaice, flounder, sole, turbot, etc.) Pihl et al 2006

16 Local effects of structures Fish abundance Fish Biodiversity Total catch of "Reef habitat fish" (numbers) Shannon-Wiener index Distance to turbine Distance (m) 16 Stenberg et al. 2015

17 How can we quantify the importance of coastal habitats for fish stocks? Spawning grounds Fishing areas (conflicts with other activities) Nursery areas Feeding grounds Migratory corridors Most important for fisheries Highest CPUE/cost of fishery? Highest landing value from fished area?

18 Potential habitats Species and life stage Environmental conditions of importance for habitat (temp, sal, depth, sediment type, etc.) Information from fishing surveys on distribution and abundance GIS baseret spatio-temporal fordeling af miljøfaktorer Habitat suitability models Integration of above information Map on potential habitats for specific species and specific life stages

19 Realised habitat What drives a choice for specific habitat? Food availability Predation Recruitment of juveniles/spawners, etc. Apart from environmental factors

20 Effective habitat Essential habitat or habitat that provides the largest contribution to Juvenile recruitment Spawning biomass Fishing grounds (eg. feeding/spawning)

21 Effective fish habitats Explore the contribution of an area to a specific fish population Biscay Bugten. LePape et al. 2003

22 South-eastern part contributed to 36% of sole recruits and to 48% of plaice recruits (age I fish). From Riou et al

23 Information sources for fish distribution and abundance Fishing surveys Commercial fishery (VMS data for skibe >12 m) Crowd sourcing (key-fishermen data) Interviews with fishers (smaller vessels) Interviews with sports and recreational fishers other (eg. project data)

24 Summary Coastal areas are vulnerable due to multiple stressors. - many coastal habitats have been damaged or lost Important to protect fish habitats - Some are essential Habitat restoration in marine environment has started in DK. - Not all is restoration, some is introduction of new habitat - Many projects locally driven and bottom up - Some habitats may restore themselves with time, others need intervention Higher complexity equates with : Higher biodiversity, abundance, growth and survival of species. 24