Coastal ecosystems of the south coast of Portugal: estuaries and lagoons - Ria Formosa - Guadiana estuary and salt marsh - fish communities, seasonality, interdecadal changes - environmental variability, climate change and fisheries Karim Erzini Dynamics of Aquatic Ecosystems 13 10-2008 RIA FORMOSA 55 km long lagoon approximately 16,300 hectares maximum width of the lagoon is 6 km maximum depths of approximately 6 m (low tide) 6 openings to the sea (barrier islands) tidal range: between 1.5 and 3.7 m very good water circulation (50% renewal every tidal cycle) extensive sea grass beds and saltmarsh 90% of the area is a Natural Park of European importance for biodiversity, Natura2000 site, important bird area (IBA), RAMSAR recreation, fishing, bait collection aquaculture Latitude ( N) 37.20 37.00 36.80 Sagres Portimão Lagos 30 100 200 500 Algarve Albufeira Quarteira Faro Olhão Fuzeta Tavira VRSA 9.20 9.00 8.80 8.60 8.40 8.20 8.00 7.80 7.60 7.40 Longitude ( W) 1
Ria Formosa (western end) Praia de Faro Max. width ~ 6 km RECRUITMENT OF SEA BREAMS (SPARIDAE) AND OTHER COMMERCIALLY IMPORTANT SPECIES IN THE ALGARVE (SOUTHERN PORTUGAL) OBJECTIVES: species composition, relative abundance, time of settlement, and size at settlement in different habitats the distribution and abundance of juvenile stages of fishes, particularly Sparidae habitat use and preferences in the inshore environment factors controlling distribution, abundance, and survivorship the dispersal / migration / recruitment from the inshore habitats to the deeper water fishing grounds present day distributions, abundances, and species composition compared with those of 13 to 15 years ago 2
Use of fishes as indicators of biological integrity Source: Whitfield, A.K. and M. Elliott. 2002. Fishes as indicators of environmental and ecological changes within estuaries: a review of progress and some suggestions for the future. J. Fish Biology 61(Suppl. A): 229-250. I. Fish Community Studies Objectives: Long-term changes in the fish community of the Ria Formosa, biodiversity Recruitment, habitat use Spatio-temporal distribution Impacts on the fish community 3
SAMPLING STRATEGY 1) Areas of strong coastal influence: BR, BP 2) Secondary canals/interior areas: IC, ID, IP 3) Main canals: CB, CD, CP Beach seine 4
Sampling locations with the 25 m beach seine (monthly, 479 samples, Oct 2000-Oct 2001) Beam trawl 5
Beam trawl sampling locations Riley push net Sample Sample location site bottom Sea bed Deep in depth shalow water Vegetation % %plant covering cover Pn1 Sand-mud 0.5 0 Pn2 Sand 0.5 0 Pn3 Sand-mud 0.5 0 Pn4 Mud-sand 1 90 Pn5 Sand-mud 1 90 Pn6 Mud-sand 1 90 6
Beam trawl sampling locations 25 m beach seine 87 different species belonging to 33 families and 52 genera 24 Average number of species 20 16 12 8 4 0 1 5 33 8 19 25 12 28 35 3 20 9 22 18 21 7 17 6 23 10 36 4 14 2 24 15 27 11 37 30 13 34 26 29 16 31 32 Sampling Locals locations Mean number of species? standard deviation at each of the 37 sampling stations 7
Total numbers of species recorded at each station sampled with the 25 m beach seine. 45 40 Total number of species 35 30 25 20 15 10 5 0 5 18 33 3 8 25 28 1 35 19 12 20 17 4 7 9 22 15 21 23 10 6 34 36 24 2 30 13 11 14 27 16 29 37 26 31 32 Sampling Locals locations Mean number of species per month Total number of species per month 20 60 50 Average number of species 15 10 5 Total number of species 40 30 20 10 0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct 0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Month Month 8
Cluster analysis: monthly data, 25 m beach seine Beam trawl: average number of species per month Total: 72 species and one genus Average number of species per sample location 25 20 15 10 5 0 Mar01 May01 Jul01 Sep01 Nov01 Jan02 Mar02 Month 9
Beam trawl: MDS Riley pushnet: a total of 51 species Total (n=51) 30 25 Number of species 20 15 10 5 0 Apr-01 May-01 Jun-01 Jul-01 Aug-01 Sep-01 Oct-01 Nov-01 Dec-01 Jan-02 Feb-02 Mar-02 Apr-02 Number of species Avg 10
GIS applications: fish density October 2000 April November December May June Diplodus vulgaris (two-banded sea bream) January July February August March September RECRUITMENT AND GROWTH October 2001 11
Comparative study Has the fish community changed since the early 1980 s? Methods 4 sampling sites (the same as those sampled by Costa Monteiro from 1981-1986) same gear (50 m beach seine, 14 mm stretched mesh), fished at low tide a sequence of three beach seine sets at each site monthly sampling over two years (2001-2002) sub-sampling in the case of large catches laboratory: identification, weighing and measuring 12
Costa Monteiro stations B, C, D and E Sampling with a 50 m beach seine 3 sets at each sampling location, monthly 13
Total catches in weight (g) per month at Station B 1980-1984 2001-2002 14
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12000 10000 N W (g) 60000 50000 Total catch (N) 8000 6000 4000 40000 30000 20000 Total weight (g) 2000 10000 0 B C D E 0 Total catch in number and in total weight (in grams) per location. Comparison of 1981-1984 with 2000-2002 Species (Station B) 1981-86 2002-02 Species (Station B) 1981-86 2002-02 Species (Station B) 1981-86 2002-02 Anguilla anguilla X X Labrus bergylta X Diplodus annularis X X Atherina spp. X Labrus mixtus X Diplodus bellottii X X Atherina presbyter X Labrus viridis X Diplodus cervinus X Halobatrachus didactylus X X Symphodus bailloni X Diplodus puntazzo X X Belone belone X X Symphodus cinereus X Diplodus sargus X X Parablennius gattorugine X X Symphodus ocellatus X Diplodus vulgaris X X Parablennius pilicornis X Symphodus roissali X Lithognathus mormyrus X X Salaria pavo X Symphodus rostratus X Oblada melanura X X Arnoglossus thori X X Dicentrarchus labrax X X Pagellus acarne X Callionymus lyra X Dicentrarchus punctatus X Pagellus bogaraveo X Callionymus maculatus X Chelon labrosus X X Pagellus erythrinus X Caranx rhonchus X Liza aurata X X Sarpa salpa X X Trachurus trachurus X X Liza ramada X X Sparus aurata X X Alosa fallax X X Liza saliens X X Spondyliosoma cantharus X X Sardina pilchardus X X Mugil cephalus X Hippocampus guttulatus X Conger conger X Mullus surmuletus X X Hippocampus hippocampus X X Engraulis encrasicolus X X Pomatomus saltatrix X Nerophis ophidion X X Diplecogaster bimaculata X Raja undulata X Syngnathus abaster X X Gobius couchi X Scorpaena notata X X Syngnathus acus X X Gobius cruentatus X Scorpaena porcus X Syngnathus typhle X X Gobius niger X Serranus cabrilla X X Sphoeroides spenglery X Gobius paganellus X Serranus hepatus X X Torpedo torpedo X Pomatoschistus microps X Microchirus theophila X Chelidonichthys lucerna X Pomatoschistus minutus X Monochirus hispidus X Lepidotrigla cavillone X Pomatoschistus pictus X Solea senegalensis X X Total 47 66 Coris julis X Boops boops X X Ctenolabrus rupestris X Dentex dentex X 17
Species comparisons Not considering Gobiidae, Labridae, Liza spp., Syngnathusspp. and Hippocampusspp.: 1980-1986: 40 species 2001-2002: 42 species 1980-1986: 14 species not in common with 2001-2002 2001-2002: 12 species not in common with 1980-1986 1 Samples PCA 0.5 E2001 D2002 E2002 2001-2002 C2002 C2001 B2002 B2001 axis 2 0 D2001 B82 B84 B85-86 D83 B80 B83 B81-0.5 C80-82 E85-86 1980-1986 -1 D85-86 -1-0.5 0 0.5 1 axis 1 18
Cluster analysis results 1980-1986 2001-2002 MDS 1 1980-1986 0.5 83B 8082C 83D 8586D 84B 81B 8586E axis 2 0-0.5 82B 80B 8586B 2002B 2001B 2001C 2002C 2001D 2002E 2001E 2002D -1 2001-2002 -1-0.5 0 0.5 1 axis 1 19
Conclusions Fish diversity appears to have increased from 1981-86 to the present Species composition is different Fish biomass seems stable comparing the two periods Individual species numbers/biomass generally comparable for the two time periods Variability may be due to variation in recruitment No negative changes in the fish community? What about other factors such as an improvement in water quality? Some new species or occurrences... 20
II. Spatio-temporal dynamics (tagging studies) 21
What are the movements within the Ria and where do the juveniles go when they leave the Ria (generally in Autumn)? Do juveniles from the Ria colonize the artificial reefs? 22
Tagging studies: floy tags 23
Tagged fish Species n % Diplodus vulgaris 2606 60.39 Dicentrarchus labrax 575 13.33 Diplodus sargus 511 11.84 Spondyliosoma cantharus 448 10.38 Diplodus annularis 100 2.32 Pomatomus saltatrix 17 0.39 Sparus aurata 11 0.25 Dicentrarchus punctatus 10 0.23 Diplodus bellottii 10 0.23 Mullus surmuletus 6 0.14 Raja undulata 4 0.09 Caranx rhonchus 3 0.07 Raja clavata 3 0.07 Boops boops 2 0.05 Solea senegalensis 2 0.05 Symphodus bailloni 2 0.05 Torpedo torpedo 2 0.05 Diplodus cervinus 1 0.02 Pagellus acarne 1 0.02 Sarpa salpa 1 0.02 Total 4315 4315 tagged fish, 305 recaptures Species Fish Total Number of times recaptured Recaptured Recaptures 1 2 3 4 5 6 Diplodus vulgaris 189 261 143 31 8 4 2 1 Spondyliosoma cantharus 17 23 13 3 1 Diplodus sargus 15 17 13 2 Dicentrarchus labrax 3 3 3 Sparus aurata 1 1 1 Total 225 305 173 36 8 5 2 1 Time between Distance travelled between captures (m) captures < 100 100 to 500 500 to 2000 2000 to 5000 > 5000 Unknown Total < 1 week 34 39 73 1 to 2 weeks 20 31 1 52 2 weeks to 1 month 26 66 6 98 1 to 3 months 28 30 17 2 77 3 to 6 months 1 1 2 > 6 months 1 1 2 Unknown 1 1 Total 109 166 25 3 1 1 305 24
Movements of tagged fish (>500 m) Telemetria acústica Artificial reefs 25
Tagging studies and future work: Limited tag return rate No tag returns from fish caught outside the Ria Evidence of high site fidelity of juveniles within the Ria III. Guadiana Estuary and Castro Marim Saltmarsh ichthyofauna food web implications of Alqueva dam 26
Framework - a project funded by the National Water Institute: Study of the environmental conditions in the estuary of the Guadiana river and adjacent coastal zones Ecosystem component - characterization / baseline studies: species composition and community structure environmental factors and variability use of and importance as a habitat for fish feeding ecology / trophic interactions Questions: Will changes in river flow affect the fish community? What are the implications for the food web? Lower Guadiana estuary and Castro Marim salt marsh sampling locations Trawl sampling locations Beach seine sampling locations monthly sampling, at night, low tide, lunar phase: last quarter, professional fishermen, Sep 2000 - Aug 2001 27
Beach seine used in Castro Marim salt marsh creeks 28
Methods Laboratory: Identification; Length and weight; Maturity stage; Stomach content analysis. Bibliography: Complementary studies; Age at first maturity; Classification: life cycle, conservation status, tolerance limits, etc... Data analysis: Diet indices, prey preferences, Multivariate analysis. Classification of fish species Classification according to reproduction, migration and occurrence: Resident species; Marine species using salt marsh/estuary as a nursery; Occasional (marine); Anadramous or catadramous migratory species; Occasional (freshwater). Habitat: Salt marsh, lower estuary, middle estuary. Maturity stage: Juvenile or adult. 29
Classification of fish species cont.. Frequency of occurrence: Very common or common, rare or occasional, very rare Trophic category: Filter feeder, detritus feeder, omnivorous, piscivorous and species feeding on invertebrates Tolerance: Fresh water species; Brackish water species; Marine. Pelagic or benthic Fish community: principal results total of 48 species (26 families) of fish in salt marsh and estuary; predominance of marine species (in particular juveniles); relatively few resident or anadramous and catadramous migratory species; Dominant/characteristic species of the salt marsh: P. microps (resident); Atherina spp. (resident); Mugilidae (resident and juveniles of marine species), juveniles of Sparidae, S. pilchardus, D. labrax, M. surmuletus(juveniles of marine species); Dominant/characteristic species of the lower estuary: H. didactylus, D. sargus, D. vulgaris, D. labrax, S. vulgaris, S. senegalensis; Lower diversity in the middle estuary; Greater diversity and abundance in the summer; Importance of salinity. 30
Lusitanian toadfish (Halobatrachus didactylus) Sand goby (Pomatochistus microps) Mullets (Liza aurata, L. ramada) Sea breams (e.g. Diplodus sargus) European bass (Dicentrarchus labrax, D. punctatus) Red mullets (Mullus surmuletus, M. barbatus) Soles (Solea senegalansis, S. vulgaris) 31
axis 2 1 0.5 0-0.5 Salt marsh Cannonical correspondence analysis Summer SET SET JUN JUL JUL MAI JUN JUN JUL MAI MAI AGO AGO MAI MAI AGO JUL NOV NOV Maximum river runoff, lowest salinity ABR ABR ABR MAR MAR MAR MAR JAN JAN JAN JAN FEV FEV -1-1 -0.5 0 0.5 1 axis 1 1 Af Mb Hd Gn 0.5 Juveniles / marine species Ss Fh Db Sa Bb Brackish and resident species PminPs axis 2 0 Ms Sp Ee Cl Ds Ls Dp Lr Mug La Ath Dv Aal Aan Pm Dl Da Pg Sc Mc -0.5-1 Cc Tt Freshwater species -1-0.5 0 0.5 1 axis 1 32
1 Af Mb Hd Gn Sal 0.5 SsFh Db Sa Bb PminPs axis 2 0 Temp Ms Sp Ee Cl Ds Ls Dp Lr Mug La Ath Dv Aal Aan Pm Dl Da Pg Sc Mc -0.5-1 Cc Tt -1-0.5 0 0.5 1 axis 1 1 Sal SET SET NOV NOV axis 2 0.5 0-0.5 Temp Summer JUN JUN JUL JUL MAI JUN JUN JUL MAI MAI AGO AGO MAI MAI AGO JUL ABR ABR ABR ABR MAR MAR MAR JAN JAN JAN JAN FEV FEV Floods, maximum runoff MAR -1-1 -0.5 0 0.5 1 axis 1 33
axis 2 1 0.5 0 Temp Sal Marine, juveniles Af Hd SET SET Gn NOV NOV ABR ABR Bb Db Sa Fh ABR JUN JUL JUL MAI JUN JUN Ee Cl Ds Ls Lr DpJUL La Ath MAI MAI Dv AGO AGOAal Aan MAI MAI Dl Da ScAGO JUL JAN Brackish, residents JAN JAN JAN FEV FEV FEV -0.5-1 MAR MAR MAR MAR Cc Tt Freshwater -1-0.5 0 0.5 1 axis 1 Zoom... axis 2 0.5 Principally juveniles: sparidae and sea basses 0 Temp Salinity Fh Sa DbJUL JUN JUN JUL JUN JUN Ds DpJUL AGO Dv AGO Aal AGO MAI Dl AGO Da Sc Bb MAI Ee Ls MAI La MAI MAI Aan ABR ABR ABR ABR Cl Lr Ath JAN JUL -0.5 0 0.5 axis 1 34
Feeding Ecology and Food Web sampling period: September 2000 - August 2001 1415 stomachs of the most important species Soles Sea basses Red mullets Sea breams Toadfish MDS based on mean seasonal values of C N % Autumn Algae, sea grass Mullidae Sparidae Echinoidea P. serratus Amphipoda Batrachoididae Polychaeta Other Teleostei C. maenas Insecta Moronidae C. crangon 35
P. serratus Winter Batrachoididae Gobiidae Polychaeta Soleidae C. maenas Other Teleostei Moronidae Other Crustacea C. crangon Spring Batrachoididae Cerastoderma spp. Fish eggs Sparidae Algae, sea grass Soleidae Amphipoda Polychaeta C. maenas Other Teleostei Gobiidae Moronidae C. crangon 36
Mullidae Summer Algae, sea grass Amphipoda Sparidae P. serratus Polychaeta Gobiidae Moronidae Insecta Other Teleostei C. crangon All Year Mullidae Cerastoderma spp. Fish eggs Sparidae Algae, sea grass Amphipoda Batrachoididae P. serratus Polychaeta Gobiidae Soleidae C. maenas Other Teleostei C. crangon Moronidae 37
Food web partly based on data from other studies Sea Robalos basses Sea breams Sargos Palaemon serratus Gobius sp Crangon crangon Phytoplankton Fitoplâncton Amphipods Amphipodes Zooplankton Zooplâncton Red Salmonetes mullets Clupeídos Small pelagics Gastropods Gastrópodes Carcinus maenas Mullets Tainhas Algas Algae, sea grasses Camarões Shrimps Isópodes Toadfish Xarroco Isopods Pulga-do-mar Moluscos Molluscs Crustaceans Crustáceos Linguados Soles Polychaetes Poliquetas Organic Matéria matter orgânica Preferential prey: Secondary prey: Literature: Alqueva dam: -storage capacity of 4.1 x 10 9 m 3 -increase of approximately 43% in terms of volume retained in dams - reduction in mean flow (60% of the 50 year mean) - less organic material, nutrients - decreased primary production - fewer high flow events - deterioration of salt marsh? - decrease in essential fish habitat? - changes in food web? - coastal fisheries? 38
IV. Climate change and fish and fisheries of the Algarve (southern Portugal) Changes in the fish fauna of the Ria Formosa lagoon (1980-1986 to 2000-2002) Records of rare or unusual catches from local commercial fisheries Relationships between Algarve landings and environmental variables Algarve coast An important transition zone: - Mediterranean influence - NE Atlantic influence - Central east Atlantic influence 39
Implications of increasing temperature Changes in the geographic distribution Occurrence of new, warm water species Disappearance of more temperate species Reproduction Changes in the fish fauna of the Ria Formosa more species in 2000-2002 (114 versus 89) stable biomass increase in subtropical species (30% versus 17.5%) e.g. Synaptura lusitanica, Microchirus boscanionand Bothus podas Not considering Gobiidae, Labridae, Liza spp., Syngnathus spp. and Hippocampus spp.: 1980-1986: 40 species 2001-2002: 42 species 1980-1986: 14 species not recorded in 2001-2002 2001-2002: 12 not recorded in 1980-1986 40
New records: Sparisoma cretense (Mediterranean parrotfish) Source:Abecasis et al. (2005) JMBA2 Biodiversity Records (published online) Species not recorded in 2000-2002 Sand eel: temperate species that has retreated north. 41
Other indicators of change: - New species reported by commercial fishers: Galeoides decadactylus (from NW Africa) Synodus saurus (from the Mediterranean) Environmental variables and landings - analysis of relationships between landings and explanatory variables such as river flow, SST and NAO - strong relationships for some species such as sardine and shrimp Caudal e Captura de sardinha (X-média/desvio padrão) 3 2 1 0-1 -2 Standardized sardine landings and Guadiana river flow Desembarques de sardinha Caudal (ano hidrológico) 1970 1975 1980 1985 1990 1995 2000 Year Ano See: Erzini, K. 2005. Trends in NE Atlantic landings (southern Portugal): identifying the relative importance of fisheries and environmental variables. Fisheries Oceanography 14: 195-209. 42
For some species such as Octopus vulgaris, no significant relationships LPUE (kg/day) 400 350 300 250 200 150 100 50 0 Jan-87 Jan-88 Jan-89 Jan-90 Jan-91 Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Trend component Jan-97 Month Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Total landings (kg) 120000 100000 80000 60000 40000 20000 0 Jan-87 Jan-88 Jan-89 Jan-90 Jan-91 Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Seasonal component Jan-97 Month Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Fishery, rather than environmentally driven dynamics? Changing scenarios: new species, new opportunities? Warmer waters could mean greater availability of large pelagics. -White marlin (Tetrapturus albidus) ) and blue marlin (Makaira nigricans) ) are summer visitors (> 20ºC); - collaboration with Big Game Fishing Association of Portugal: data collection (catches, feeding ecology, environmental data) Vilamoura, blue marlin, 750kg, August 1993, >20ºC White marlin Blue azul 43
Changing scenarios: loss of commercial species? Raja undulata GSI nas Fêmeas 5 4 3 2 1 0 PENICHE Verão Outono Inverno Primavera Estação Example of a species with a limited reproductive period (winter) in the Algarve with an increase of 1-2ºC, it will probably no longer reproduce in Algarve waters Dados: Coelho & Erzini (2006); Moura et al. (2007.) Map: adapted from Atlas do Ambiente Digital Instituto do Ambiente GSI nas Fêmeas 6 5 4 3 2 1 0 ALGARVE Verão Outono Inverno Primavera Estação Importance of longterm monitoring: Ria Formosa: annual beach seine surveys since 2000 Arade river estuary: annual surveys since 2004 Sportfishing (large pelagics) Collaboration with commercial fishermen 1980-1984 Sarpa salpa 2000-2001 44
Bibliography Abecasis, D.; Bentes, L.; Ribeiro, J.; Machado, D.; Oliveira, F.; Veiga, P.; Gonçalves, J.M.S. & Erzini, K. (2006) First record of the Mediterranean parrotfish, Sparisoma cretense in Ria Formosa (south Portugal). JMBA2 - Biodiversity records. Almeida, C., R. Coelho, M. Silva, L. Bentes, P. Monteiro, J.Ribeiro, K. Erzini and J.M.S.Gonçalves 2008 Use of different intertidal habitats by faunal communities in a temperate coastal lagoon. Esturarine, Coastal and Shelf Science (in press) Curtis, J., Ribeiro, J., Erzini, K. and A. Vincent 2007. A conservation tradeoff? Interspecific differences in seahorse responses to experimental changes in fishing effort. Aquatic Conservation: Marine and Freshwater Ecosystems 17: 468-484. Erzini, K. 2005. Trends in NE Atlantic landings (southern Portugal): identifying the relative importance of fisheries and environmental variables. Fisheries Oceanography 14: 195-209. Oliveira, F., Erzini, K. and J.M.S. Gonçalves. 2007. Feeding habits of the deep-snouted pipefish Syngnathus typhle Linnaeus, 1758. Estuarine Coastal and Shelf Science 72: 337-347. Ribeiro, J., Bentes, L., Coelho, R., Gonçalves, J.M.S., Lino, P. and K. Erzini. Seasonal, tidal and diurnal changes in fish assemblages associated with seagrass and sand habitats of the Ria Formosa lagoon (Portugal). 2006. Estuarine Coastal and Shelf Science 67: 461-474. Ribeiro, J., C.C. Monteiro, P. Monteiro, L. Bentes, R. Coelho, J.M.S. Gonçalves, P.G. Lino and K. Erzini. 2008. Long-term changes in fish communities of the Ria Formosa coastal lagoon (southern Portugal) based on two studies made 20 years apart. Estuarine, Coastal and Shelf Science, 76: 57-68. Sá, R., Bexiga, C., Veiga, P., Vieira, L. and K. Erzini. 2006.Feeding ecology and trophic relationships of the main fish species of the lower Guadiana river estuary and Castro Marim and Vila Real de Santo António salt marsh. Estuarine Coastal and Shelf Science 70: 19-26. Veiga, P., Vieira, L., Bexiga, C., Sá, R. and K. Erzini. 2006. Fish assemblages of the Castro Marim saltmarsh (southern Portugal): structure and temporal variation. Estuarine Coastal and Shelf Science 70: 27-38. 45