Crecimiento relativo del cangrejo semiterrestre Pachygrapsus marmoratus: un enfoque a partir de la teoría de la información

The patterns of allometric growth of the grapsid crab Pachygrapsus marmoratus were investigated with an information-theoretic approach. This approach is beneficial, more robust, and may reveal more information than the classical approaches (e.g. hypothesis testing). No differentiation in allometric growth was detected between right and left chelar propods in either sex. Significant sexual differentiation in the allometric growth of chelar propods, abdominal somites and telson was found. It was shown that the allometry of chelar propodus width may be used to identify puberty in males, as there is a marked breakpoint at a carapace width of ~16.0 mm. For females, puberty was identified by the breakpoint in the allometry of the third and fourth abdominal somites at a carapace width of ~16.5 mm. In many cases (e.g. in chelar propods of males, or in most abdominal somites and the telson in females) the classic allometric equation log Y = log a + b log X has no essential support and non-linear allometric models between the log-transformed morphometric characters have to be used.Los patrones de crecimiento alométrico del cangrejo gráspido Pachygrapsus marmoratus, fueron investigados mediante un enfoque a partir de la teoría de la información. Esta aproximación es más robusta, completa, y puede revelar más información que los estudios clásicos (como la comprobación de hipótesis). No se detectó diferenciación en el crecimiento alométrico en los quelípedos derecho e izquierdo en ambos sexos. Sí se halló una diferenciación sexual importante entre el crecimiento alométrico de quelípedos, segmentos abdominales y telson. Se demostró que la alometría del ancho de los quelípedos puede utilizarse para identificar la pubertad en los machos, ya que hay un marcado punto de rotura en una anchura de caparazón de ~16.0 mm. En las hembras, la pubertad se identifica por el punto de rotura en la alometría de los segmentos abdominales tercero y cuarto con un ancho de caparazón de ~16.5 mm. En muchos casos (por ejemplo en los quelípedos de los machos o en la mayoría de los segmentos y el telson en las hembras) la ecuación alométrica clásica log Y = log a + b log X no tiene esencialmente ninguna base y deben utilizarse modelos alométricos no lineales entre los caracteres morfométricos trasformados logarítmicamente

New Mediterranean biodiversity records (October, 2014)

The Collective Article 'New Mediterranean Biodiversity Records' of the Mediterranean Marine Science journal offers the means to publish biodiversity records in the Mediterranean Sea. The current article is divided in two parts, for records of alien and native species respectively. The new records of alien species include: the red alga Asparagopsis taxiformis (Crete and Lakonikos Gulf, Greece); the red alga Grateloupia turuturu (along the Israeli Mediterranean shore); the mantis shrimp Clorida albolitura (Gulf of Antalya, Turkey); the mud crab Dyspanopeus sayi (Mar Piccolo of Taranto, Ionian Sea); the blue crab Callinectes sapidus (Chios Island, Greece); the isopod Paracerceis sculpta (northern Aegean Sea, Greece); the sea urchin Diadema setosum (Gökova Bay, Turkey); the molluscs Smaragdia souverbiana, Murex forskoehlii, Fusinus verrucosus, Circenita callipyga, and Aplysia dactylomela (Syria); the cephalaspidean mollusc Haminoea cyanomarginata (Baia di Puolo, Massa Lubrense, Campania, southern Italy); the topmouth gudgeon Pseudorasbora parva (Civitavecchia, Tyrrhenian Sea); the fangtooth moray Enchelycore anatina (Plemmirio marine reserve, Sicily); the silver-cheeked toadfish Lagocephalus sceleratus (Saros Bay, Turkey; and Ibiza channel, Spain); the Indo-Pacific ascidian Herdmania momus in Kastelorizo Island (Greece); and the foraminiferal Clavulina multicamerata (Saronikos Gulf, Greece). The record of L. sceleratus in Spain consists the deepest (350-400m depth) record of the species in the Mediterranean Sea. The new records of native species include: first record of the ctenophore Cestum veneris in Turkish marine waters; the presence of Holothuria tubulosa and Holothuria polii in the Bay of Igoumenitsa (Greece); the first recorded sighting of the bull ray Pteromylaeus bovinus in Maltese waters; and a new record of the fish Lobotes surinamensis from Maliakos Gulf.peer-reviewe

The influence of infaunal (Nereis diversicolor) abundance on degradation of organic matter in sandy sediments

The influence of the infaunal polychaete Nereis diversicolor on the degradation of aged detritus (Fucus sp.) deposited 3 cm below the sediment surface was investigated as a function of worm density (0, 600, 1200 and 2400 m− 2) in manipulated laboratory microcosms. Benthic metabolism in the microcosms was determined as sediment–water fluxes of dissolved carbon and microbial sulfate reduction. In addition, the vertical distribution of key sediment parameters, such as porewater solutes and bacterial abundance and community fingerprint (based on 16S rDNA) were determined at the end of the experimental period. Porewater concentrations of TCO2, DOC, and NH4+ were negatively related to worm density as a result of irrigation mediated excess transport. Conversely, sediment–water fluxes increased linearly with increasing macrofaunal abundance. Total benthic metabolism (TCO2 and O2 flux) was stimulated by up to 75% in unamended and 175% in detritus enriched treatments. The high faunal stimulation of benthic metabolism in the Fucus enriched sediment was primarily due to increased aerobic microbial metabolism resulting in a more efficient mineralisation of the released DOC and thus faster decay of the aged detritus. Sediment bacteria in the detritus amended treatment seemed to rapidly assimilate NH4+ within the sediment when utilising the added nitrogen-deficient detritus. NH4+ fluxes were similar in both amended and unamended treatments but increased with animal density, suggesting that animal excretion contributed significantly to the NH4+ flux. Analysis of the bacterial community showed that the addition of detritus significantly changed both its abundance and composition compared to unamended treatments. These differences were gradually alleviated with increasing animal abundance. Our results show that N. diversicolor abundance is a significant factor that determines not only total benthic metabolism, but also organic matter degradation pathways and microbial community composition, and a possible reduction of natural populations would result to changes in sediment biogeochemistry.We thank the late Hanne Brandt for performing CHN analysis. EK was supported by Grant # 21020463 from the Danish Science Research Council. SP was supported by a grant from the Greek State's Scholarships Foundation and a travel scholarship from the European Association of Organic Geochemists.Peer Reviewe

Vulnerability of marine habitats to the invasive green alga Caulerpa racemosa var. cylindracea within a marine protected area

International audienceThe relative vulnerability of various habitat types to var. invasion was investigated in the National Marine Park of Zakynthos (Ionian Sea, Greece). The density of fronds was modelled with generalized additive models for location, scale and shape (GAMLSS), based on an information theory approach. The species was present in as much as 33% of 748 randomly placed quadrats, which documents its aggressive establishment in the area. The probability of presence of the alga within randomly placed 20 x 20 cm quadrats was 83% on 'matte morte' (zones of fibrous remnants of a former bed), 69% on rocky bottoms, 86% along the margins of meadows, 10% on sandy/muddy substrates, and 6% within meadows. The high frond density on 'matte morte' and rocky bottoms indicates their high vulnerability. The lowest frond density was observed within meadows. However, on the margins of meadows and within gaps in fragmented meadows relative high densities were observed. Such gaps within meadows represent spots of high vulnerability to invasion

Rast, smrtnost i prinos po novačenju dekapodnog raka karlića, Upogebia pusilla (Petagna, 1792) (Crustacea: Decapoda: Gebiede), u zapadnom dijelu Grčke

The paper presents data on growth, mortality and yield of the mud prawn Upogebia pusilla in western Greece. The species is intensively exploited in the area as live bait for hand lines and long lines both for professional and sport fishermen. The study area is a closed bay in western Greece with a small opening which connects it to the Ionian Sea. Longevity of the species in the study area was found to be 4+ years. Females’ total length ranged between 18 and 54 mm; for males it ranged between 16 and 58 mm. The von Bertalanffy parameters for males were L∞=60.30 mm, K=0.520 per year and t0=-0.0166 years; for females they were L∞=58.80 mm, K=0.621 per year and t0=- 0.1261 years. Overall von Bertalanffy equation parameters were L∞=61.05 mm, K=0.521 per year and t0=0.086 years. Maximum weight was estimated as 3.440 g at L∞ based on the length-weight relationship. Mortality estimates were Z=1.510 per year, M=0.928 per year and F=0.582 per year resulting in an exploitation ratio of E=39%. Using the above values, yield per recruit was estimated at 2.97 g/year at Fmax levels of 0.750 per year and Eopt=50%. Overall length-weight relationship was estimated as: W = 0.01589TL2.972, r2 = 0.886. This paper contributes to the knowledge of population dynamics of the species Upogebia pusilla and in particular, growth, mortality and yield.U ovom radu izneseni su podaci o rastu, smrtnosti i prinosu dekapodnog raka karlića Upogebia pusilla u zapadnoj Grčkoj. Vrsta se intenzivno iskorištava u području kao živi mamac za ručne linije i duge linije, te je koriste profesionalni i sportski ribolovci. Istraživano područje je zatvorena uvala u zapadnoj Grčkoj s malim otvorom koji je povezuje s Jonskom morem. Dugovječnost vrsta u istraživanom području inosila je 4 + godine. Ukupna dužina ženki se kretala između 18 i 54 mm, a mužjaka između 16 i 58 mm. Dobivene vrijednosti izračunate su prema jednadžbi von Bertalanffy-a, te su za mužjake iznosile: L ∞ = 60,30 mm, K = 0,520 i t0 = -0.0166, dok su za ženke iznosile: L ∞ = 58,80 mm, K = 0,621 i t0 = -0.1261. Ukupni parameteri dobiveni prema jednadžbi von Bertalanffy-a su iznosili: L ∞=61.05 mm, K=0.521 i t0=0.086 years. Maksimalna procijenjena masa je iznosila 3.440 g na temelju dužinsko-masenog odnosa. Procjene smrtnosti bile su: Z = 1,510 godišnje, M = 0,928 godišnje, a F = 0,582 godišnje, što je rezultiralo eksploatacijskim omjerom E = 39%. Koristeći gore navedene vrijednosti, prinos po novačenju je iznosio 2.97 g/godišnje na Fmax nivoima od 0.750 godišnje i Eopt=50%. Ukupni dužinsko-maseni odnos iznosi: W = 0.01589TL2.972 r2 = 0.886. Ovaj rad pridonosi poznavanju dinamike populacije vrste dekapodnog raka karlića, a posebice njegovog rasta, smrtnosti i prinosa po novačenju

Spread of hard bottom species of interest at the National Marine Park of Zakytnhos

The presence study estimates the occupancy of five benthic species (three starfish: Echinaster sepositus, the protected Ophidiaster ophidianus, Hacelia attenuata and two fishes: the protected Epinephelus marginatus and Sparisoma cretense) on the hard bottom substrate of the gulf of Laganas, in the National Marine Park of Zakynthos. Occupancy differences: for the two starfish, among coastline and insular sites of study, for Epinephelus marginatus among different types of hard substrate and for Sparisoma cretense among the three protection Zones of the NMPZ. The detection probability in all the cases was taken into account. The four species (except Hacelia attenuata) were found established in the study area.JRC.H.1-Water Resource