23/11/2012 Decapod crustacean larval communities in the western Mediterranean: composition and vertical distribution patterns Asvin P. Torres Coauthors : A. Dos Santos, R. Balbín, F. Alemany, E. Massutí, P. Reglero Collaborators : Dr. Pere Abelló (ICM, Barcelona), Dr. Guillermo Guerao (IRTA, Tarragona) & Dr. José Antonio Cuesta (CSIC, Cádiz) This work was supported by: - IDEADOS (CTM2008-04489-C03-01), Spanish Plan R+D+i. - FPI Fellowship Regional Government of the Balearic Islands (European Social Fund ) General framework: Decapod crustaceans larvae • Ecological studies regarding decapod larvae are scarce in Mediterranean Sea mainly due to the level of expertise necessary to identify them from plankton samples • The first step to produce useful information on their ecology is to have accurate data on their morphology and taxonomy • In the Mediterranean, decapod larval studies have focused on morphological descriptions and surface distributions of some groups Who, When and Where they are? What is happenning along the whole water column? 1 23/11/2012 Main questions in this study 1) The taxonomic composition of decapod crustacean larval communities: - New records - New development larval stages 2) Seasonal and horizontal distribution of the main decapod larval assemblages 3) The vertical distribution of the larvae according to their life history traits Sampling & analysis method 2 Areas 2 seasons NorthWest 2 isobaths (shelf/slope) R/V Sarmiento de Gamboa South VERTICALR/V Sarmiento de Gamboa Winter Summer 2009 2010 200 m 900m NorthWest 200m Profundidad(m) South MULTINET / MOCNESS 0.3 mm mesh size 900m 200m 900 m 2 23/11/2012 Question 1: Describe the decapod crustacean larvae 218 mesozooplankton samples / 7448 indiv. / 120 Taxa: HIGH DIVERSITY Sergestes arcticus Zoea I Sergestes vigilax Polycheles typhlops Lysmata seticaudata Zoea VIII Protozoea III Zoea II Antena A. antennatus Decapodito Sergestes sp. Megalopa Polychelidae Nepinnotheres Megalopa Juvenil & Megalopa pinnotheres Zoea II Liocarcinus sp . moult Pisidia sp . Q.1: Taxonomy results (2012) First record of Palaemon macrodactylus Rathbun, 1902 7 Zoea III (Decapoda, Palaemonidae) in the Mediterranean Sea. Medit. Mar. Sci., 13/2, 2012, 278-282 1 Zoea VI Mediterráneo Oriental shrimp 3 23/11/2012 Q.1: Taxonomy results (2012) “New findings on larval stages of crustacean decapods of interest for conservation and fishing exploitation in the Western Mediterranean” Scientia Marina (Submitted) Scyllarides latus: Slipper lobster Parapenaeus longirostris: Pink shrimp 4-100 m 200 m 10-140 m 150-400 m Maja squinado: Spider crab Aristeus antennatus: NEW STAGE Red shrimp 450-800 m 900 m Main questions in this study 1) The taxonomic composition of decapod crustacean larvae: - New species - New development larval stages 2) Seasonal and horizontal distribution of the main decapod larval assemblages 3) The vertical distribution of the larvae according to their life history traits Analysis: • Integrated water column observations of species densities: – Cluster – Multidimensional scaling (MDS) – Species % contribution Cluster_grup (SIMPER) 4 23/11/2012 Question 2: Results integrated water column Winter_South_Shelf (W_S_S) 3 main larval assemblages Winter Summer Species_dens Transform: Square root Resemblance: S17 Bray Curtis similarity 20 Transform: Square root Resemblance: S17 Bray Curtis similarity 2D Stress: 0,13 Survey Winter_South_Shelf S W 40 Similarity Winter 38 Summer 60 Similarity 80 100 Samples Cluster analysis Multidimensional scaling (MDS) Question 2: Characterizing the larvae communities Winter Dominated by few species Summer WSS: shelf / W: oceanic No clear dominance; with many species WINTER_SOUTH_SHELF • Gennadas elegans • Gennadas elegans Pelagic shrimp Ohter pelagic species • Caridea Benthic species as: Alpheus • Caridea benthic as Plesionika spp. glaber , Plesionika spp. and Processa spp . • Crab Goneplax rhomboides • Crab species as Ebalia WINTER spp, Parthenope spp. Pelagic shrimps species as • Gennadas elegans • Sergestes arcticus SIMPER analysis 5 23/11/2012 Question 2: Characterizing the larvae communities Winter_South_Shelf Sergestoidea In each cluster Sergestes arcticus Penaeoidea Gennadas elegans group dominates Plesionika spp.* Caridea Goneplax rhomboides Brachyura different taxa Pagurus spp. category (*) Anomura 0 10 20 30 40 50 % Contrib. Winter The predominant Sergestes arcticus Gennadas elegans species in each Plesionika spp. * category is the same in different 0 10 20 30 40 50 % Contrib. clusters except Summer Brachyura Sergestes arcticus Goneplax rhomboides SHELF Gennadas elegans * Ebalia spp. SHELF/SLOPE Plesionika spp. Ebalia spp. 0 10 20 30 40 50 % Contrib. Main questions in this study 1) The taxonomic composition of decapod crustacean larvae: - New species - New development larval stages 2) Seasonal and horizontal distribution of the main decapod larval assemblages 3) The vertical distribution of the larvae according to their life history traits Analysis: • Stratified distribution water column of species densities: – Exploratory: bar diagrams – Generalized additive models (GAMs) 6 23/11/2012 Question 3: Stratified distribution analysis WinterSouthShelf Winter Summer 0 The taxonomic category -20 57.7 m changes its weighted mean -40 63.6m -60 79 m depth (WMD ) according the -80 cluster where it appears -100 -120 Caridea -140 0 -20 63.5 m -40 55.5 m -60 -80 -100 127.1 m Depth (m) -120 -140 Penaeoidea 0 -20 56.6 m -40 41 m -60 -80 108 m -100 -120 Sergestoidea -140 Question 3: Vertical distribution Observeddistribution Estimatedeffect of Z on the larval density 0 0.1 0.2 0.3 -0 + Winter_S_S The larvae 50 50 show Z (m) 100 100 preference for 150 150 the photic (100-200 m) and not for Winter 0 0.4 0.8 0 deeper layers. 0 0 - + 200 200 Z (m) 400 400 600 600 Summer 0 1 2 3 0 0 0 - + 100 100 Generalized Z (m) 200 200 additive 300 300 models 400 400 (p<0.0001) 7 23/11/2012 Question 3: Vertical distribution Observeddistribution Estimatedeffect of Z on the larval density Winter_S_S -0 + 50 50 Representation of Z (m) the first 165 m 100 100 150 150 The larvae are no randomly distributed over 0 Winter - + the euphotic 50 50 zone. Z (m) Different peaks 100 100 150 150 Summer -0 + 50 50 Z (m) Generalized 100 100 additive models 150 150 (p<0.0001) Example commun in 3 assemblages: Bathypelagic species: G. elegans Observeddistribution Estimatedeffect of Z on the larval density 0 Winter_S_S - + Z (m) 5050 50 100100 100 150150 150 -0 + Gennadas Winter elegans Z (m) 5050 50 Early stages 100100 100 (PzI+PzII) 150150 150 Summer -0 + 5050 50 Generalized Z (m) additive 100100 100 models (p<0.0001) 150150 150 8 23/11/2012 Vertical early stage of G. elegans + environmental distribution Observeddistribution Environmental Winter_South_Shelf Winter_S_S Winter 50 Z (m) Summer 0,1 0,2 0,3 0,4 0,5 10 15 20 25 30 0 0 50 100 150 200 100 0 50 100 150 200 150 Winter Fluo Tº Z (m) 50 T º Fluo 100 150 Summer 50 Z (m) Early stages densities 100 peaks ~ Fluo peaks 150 Environmental conditions could explain larval assemblages Winter situation There is no single Winter factor to explain Dominated by few species the distribution of WSS: shelf / W: oceanic decapod larvae Winter WinterSouthShelf C-200 C-900 Winter Eg. Winter hydrographic front & chlorophyll WinterSouthShelf (Balbin et al., 2012) 9 23/11/2012 Conclusions This work adds knowledge to species with interest for fisheries and conservation, providing description of new larval stages and their spatial distribution. First record of Palaemon macrodactylus , an invasive species, was reported in the Mediterranean Sea. Three assemblages of decapod larvae off Balearic Islands were identified along the year. The summer assemblage is dominated by a set of species without any clearly dominant. The winter assemblages on the contrary are dominated by few species but with, different associations related with hydrography. All decapod larvae have a preference for the euphotic zone. Species composition is relevant to understand the vertical patterns. A good example is G. elegans , whose early stages are associated to fluorescence maxima. 10.