Ictioplancton asociado a praderas de Posidonia oceanica durante la época estival en la reserva marina de Tabarca

El hábitat es un factor decisivo en la supervivencia de los estadios tempranos. Los objetivos de este trabajo se centran en describir el poblamiento ictioplantónico de la pradera de P. oceanica en la reserva marina de Tabarca, así comosu comportamiento según el periodo día-noche. Se calaron redes fijas a nivel de P. oceanica y a 2 m por encima de ella durante cinco días en julio de 2000. Se capturaron 353 larvas. Las familias más abundantes fueron Clupeidae, Sparidae, Engraulidae y Gobbidae, representando el 31%, el 27%, el 11% y el 6%, respectivamente. Especies de pequeño tamaño presentan capacidad de seleccionar el hábitat. Concluimos que la pradera de P. oceanica es un factor determinante de la estructura del poblamiento larvario de especies demersales. Palabras clave: Larvas de peces, Fanerógamas marinas, Refugio, Redes fijas de plancton.Habitat complexity plays a key role in survival in early stages of fish larvae. We investigated fish larvae assemblage and its relation with P. oceanica seagrass at the Tabarca Island Marine Reserve. Samples were taken using moored plankton nets at two depths (0 and 2 m from P. oceanica meadow) over five consecutive days in July 2000. Three hundred and fifty-three larvae were captured. The most abundant families were Clupeidae (31%), Sparidae (27%), Engraulidae (11%) and Gobiidae (6%). We observed that small fish larvae were able to select nursery areas. We conclude that the P. oceanica leaf canopy is a major factor in structuring the larval fish assemblages of some demersal species. Key words: Fish larvae, Seagrasses, Habitat shelter, Moored plankton nets.El hábitat es un factor decisivo en la supervivencia de los estadios tempranos. Los objetivos de este trabajo se centran en describir el poblamiento ictioplantónico de la pradera de P. oceanica en la reserva marina de Tabarca, así comosu comportamiento según el periodo día-noche. Se calaron redes fijas a nivel de P. oceanica y a 2 m por encima de ella durante cinco días en julio de 2000. Se capturaron 353 larvas. Las familias más abundantes fueron Clupeidae, Sparidae, Engraulidae y Gobbidae, representando el 31%, el 27%, el 11% y el 6%, respectivamente. Especies de pequeño tamaño presentan capacidad de seleccionar el hábitat. Concluimos que la pradera de P. oceanica es un factor determinante de la estructura del poblamiento larvario de especies demersales. Palabras clave: Larvas de peces, Fanerógamas marinas, Refugio, Redes fijas de plancton

Caprellid assemblages (Crustacea: Amphipoda) in shallow waters invaded by Caulerpa racemosa var. cylindracea from southeastern Spain

Growth of the invasive algae Caulerpa racemosa var. cylindracea in shallow habitats may inXuence the faunal assemblage composition. We studied its eVects on caprellid assemblages associated with shallow-water habitats of hard and soft bottoms from the SE Iberian Peninsula (native rocky-bottom algae, C. racemosa from hard and soft bottoms, and Caulerpa prolifera, Cymodocea nodosa and Posidonia oceanica from soft bottoms). Samples were taken in two diVerent sampling periods (September 2004 and March 2005). A total of seven caprellid species were identiWed, with important diVerences in their distribution in diVerent habitats. Total abundance of caprellids was very high in March on native algae on hard bottoms, and on C. racemosa on both soft and hard bottoms. On both hard and soft bottoms, abundances of Caprella hirsuta recorded from C. racemosa were low. On the other hand, a higher abundance of other species, namely C. acanthifera, C. santosrosai, Phtisica marina and Pseudoprotella phasma, was recorded from C. racemosa. The results indicate that C. racemosa may have a positive inXuence on some caprellid species, while seasonal changes are also evident. It is concluded that introduced C. racemosa may serve as a new habitat, promoting and maintaining caprellid populations in shallow Mediterranean habitats.Ministerio de Educación y Ciencia de España y fondos FEDER de la Unión Europea. CGL2007-60044/BOSConsejería de Innovación, Ciencia y Empresa de la Junta de Andalucía. P07-RNM-0252

Ichthyoplankton composition and variability of a shallow coastal area in the Tabarca Marine Reserve, southeast Iberian Peninsula

We studied the ichthyoplankton assemblage (eggs and larvae) in a shallow coastal area in the Tabarca Marine Reserve (southeast Spain, Mediterranean Sea). Samples were taken during four different months of the same year, covering different temporal scales (season, moon phase, and day-night), and were obtained from two sampling sites, 1 km apart. The temporal variability of catches is discussed, and their relationships with the factors studied. Channel plankton nets were used in order to get the habitat associated assemblage. We captures 21 855 eggs (mean 140.41 eggs/100 m³, SD 260.36) and 4 542 larvae (mean 42.45 larvae/100 m³, SD 82.9). Ninety-nine percent of the larvae were pre-flexion. We identified 20 families. The most abundant taxonomic groups were: Gobiesocidae (31.8 %), Gobiidae (31.7 %), Sardina pilchardus (11.1 %), Bleniidae (7.5 %), Sparidae (6.9 %), Sardinella aurita (2.6 %), Serranidae (2.4 %) and Atherinidae (1.8 %). The resulting assemblage was more similar to that of estuaries and coastal lagoons than coastal shelf areas. The results showed no evidence of retention of commercial species larvae, which may be exported with currents. Analysis showed no difference between both sampling sites. Higher larvae and eggs densities were found in August and June. Eggs variability was associated with the moon phase, i.e., higher catches during the new moon and the first quarter, although there were not differences between day and night. Nocturnal larvae catches were higher, and differences between night and day were more accentuated during dark moon phases.La comunidad de ictioplancton (huevos y larvas) en una zona somera de la reserva marina de Tabarca fue caracterizada a distintas escalas temporales a lo largo de un año (estación, fase lunar y día-noche). Se discute la variabilidad temporal que mostraron las capturas de huevos y larvas, y su posible relación con los factores estudiados. Se utilizaron redes de plancton fijas. Fueron capturados en total 21 855 huevos (media 140,41 individuos/100 m³, SD 260,36) y 4 542 larvas (media 42,45 individuos/100 m³, SD 82,9). Las larvas preflexión constituyeron el 99 % de las capturas. Se identificó un total de 20 familias. Las categorías taxonómicas más abundantes fueron Gobiesocidae (31,8 %), Gobiidae (31,7 %), Sardina pilchardus (11,1 %), Bleniidae (7,5 %), Sparidae (6,9 %), Sardinella aurita (2,6 %), Serranidae (2,4 %) y Atherinidae (1,8 %). La composición de la comunidad se asemejó a la encontrada en estuarios y lagunas costeras por otros autores, más que a la encontrada en zonas de plataforma cercanas. No hay evidencias de que la reserva marina actúe como zona de retención de larvas de especies comerciales, sino más bien de exportación. No hubo diferencias entre las dos localidades de muestreo. Las mayores densidades de huevos y larvas aparecieron en los meses de agosto y junio. Los huevos mostraron cierta variabilidad relacionada con la fase lunar, con mayores capturas en cuarto creciente y luna nueva, pero no tuvieron diferencias día-noche. Las larvas mostraron una mayor densidad durante la noche, con mayores diferencias respecto al día en las fases lunares oscuras.Instituto Español de Oceanografí

Multiscaling analysis of Posidonia oceanica (L.) Delile, 1813 fish assemblage in Alicante (southeast Iberian Peninsula)

The aim of this study is to describe a Posidonia oceanica (L.) Delile, 1813 fish community and detect any daily changes in its composition at different spatial levels. Posidonia oceanica appears at depths from 0 to 30-40 meters, depending on water transparency. Its importance is based on the high number of associated fishes and invertebrates attracted by its spatial heterogeneity and variety of habitats compared with no vegetated areas. The fishing gear knows as beam trawl (1.8 meters of width and 0.8 meters of height) was used, at six localities. Each of these localities was divided in six subdivision (sites), of which we randomly sampled three by the day and three at night. Three replicates were performed at each site, for a total of 108 samples. In an overall catch of 8 747 specimens, 53 species were found, the most numerous being Diplodus annularis (1 493), Serranus scriba (1 326), Symphodus rostratus (1 156) and Symphodus cinereus (665). The nocturnal catches, compared with the diurnal, were more abundant, with a higher number of species and specimens.En este estudio se pretende describir la comunidad de peces de Posidonia oceanica (L.) Delile, 1813 y detectar el efecto producido por el periodo del día considerando diferentes escalas espaciales. Posidonia oceanica se encuentra desde la superficie hasta los 30 o 40 metros de profundidad, en función de la transparencia del agua. Su importancia se basa en el alto número de peces e invertebrados que están asociados a ella debido a su alta heterogeneidad espacial y a su gran variedad de hábitats si se compara con zonas sin vegetación. Para ello, se utilizó un gánguil (1,8 metros de anchura por 0,8 metros de altura), y se consideraron seis localidades. En cada una de ellas, se eligieron seis sitios, de los que se muestrearon, al azar, tres de día y tres de noche. En cada uno de estos sitios se realizaron tres réplicas, lo que da un total de 108 muestras. Se capturaron 8 747 individuos pertenecientes a 53 especies, siendo las más numerosas Diplodus annularis (1 493), Serranus scriba (1 326), Symphodus rostratus (1 156) y Symphodus cinereus (665). Las capturas nocturnas fueron más abundantes en cuanto a diversidad y abundancia.Instituto Español de Oceanografí

Attraction - production effects of an artificial reef on the fish community from the Tabarca Marin Reserve (Alicante)

In order to determine de attraction - production effects of the artificial reef from Tabarca Island (Alicante, southeast Spain), size-class distributions were subjected to uni- and multivariant analyses. Results indicated a low contribution of the smallest size-class, considered sub-adults. The Tabarca Island artificial reef seems to function as an attractive structure which favours the concentration of adult fish coming from other nearby habitats. Its use in the commercial fisheries could be controversial.Para determinar el efecto producción - atracción del arrecife artificial de Tabarca, se analizó la estructura de tallas del poblamiento íctico asociado mediante análisis univariantes y multivariantes. Los resultados indicaron una baja contribución de la clase de talla 1 en el conjunto del poblamiento, considerándose a la mayoría de estos individuos subadultos o juveniles tardíos. El arrecife artificial de Tabarca parece funcionar como una estructura de atracción que favorece la concentración de peces adultos procedentes de fondos cercanos. Su utilización con fines pesqueros puede ser discutible.Instituto Español de Oceanografí

A multiscaling approach to the study of the fish fauna on the rocky bottom of Ceuta (Spain)

The fish population off the coast of Ceuta (Spain) was sampled using visual censuses. Different spatial scales were used. Two sectors were defined, one of them with Mediterranean influence and the other with Atlantic influence. The population's composition showed differences between sectors, due to biogeographic factors, in the structuring of the fish assemblagse. The number of species, the diversity and the biomass presented significant differences only on a smaller spatial scale, due to the rocky habitat's heterogeneity. On a large spatial scale, the structure of the assemblage was dominated by pelagic wandering species, whereas on a smaller scale, the small-sized sedentary demersal species were more important. The trophic structure showed a predominance of microphages, followed by carnivorous mesophages, due to the exploitation level which the study zone suffers. Our results indicate the coast of Ceuta's potential as a diversity centre for fish fauna.Se estudió la ictiofauna litoral de Ceuta mediante censos visuales a varias escalas espaciales. Se diferenciaron dos sectores: uno con influencia mediterránea y otro con influencia atlántica. La composición del poblamiento mostró diferencias entre sectores debidas a factores de índole biogeográfico. El número de especies, la diversidad y la biomasa fueron significativamente diferentes sólo a la escala espacial menor, debido a la heterogeneidad estructural del hábitat. A gran escala espacial, la estructura del poblamiento estuvo dominada por especies pelágicas errantes, mientras que a escala menor tuvieron más importancia las especies demersales sedentarias de pequeño tamaño. La estructura trófica mostró un predominio de los micrófagos, grupo seguido de los carnívoros mesófagos, como consecuencia directa del nivel de explotación al que se ve sometida la zona de estudio. Los resultados han mostrado el potencial del litoral ceutí como centro de diversidad de la fauna íctica.Instituto Español de Oceanografí

Review of the effects of protection in marine protected areas: current knowledge and gaps

The effectiveness of marine protected areas (MPAs) and the conservation of marine environments must be based on reliable information on the quality of the marine environment that can be obtained in a reasonable timeframe. We reviewed studies that evaluated all aspects related to the effectiveness of MPAs in order to describe how the studies were conducted and to detect fields in which research is lacking. Existing parameters used to evaluate the effectiveness of MPAs are summarised. Two-hundred and twenty-two publications were reviewed. We identified the most commonly used study subjects and methodological approaches. Most of the studies concentrated on biological parameters. Peer reviewed studies were based on control vs. impact design. BACI and mBACI designs were used in very few studies. Through this review, we have identified gaps in the objectives assigned to MPAs and the way in which they have been evaluated. We suggest some guidelines aimedat improving the assessment of the effects of protection in MPAs

Proxy Measures of Fitness Suggest Coastal Fish Farms Can Act as Population Sources and Not Ecological Traps for Wild Gadoid Fish

Background: Ecological traps form when artificial structures are added to natural habitats and induce mismatches between habitat preferences and fitness consequences. Their existence in terrestrial systems has been documented, yet little evidence suggests they occur in marine environments. Coastal fish farms are widespread artificial structures in coastal ecosystems and are highly attractive to wild fish. Methodology/Principal Findings: To investigate if coastal salmon farms act as ecological traps for wild Atlantic cod (Gadus morhua) and saithe (Pollachius virens), we compared proxy measures of fitness between farm-associated fish and control fish caught distant from farms in nine locations throughout coastal Norway, the largest coastal fish farming industry in the world. Farms modified wild fish diets in both quality and quantity, thereby providing farm-associated wild fish with a strong trophic subsidy. This translated to greater somatic (saithe: 1.06–1.12 times; cod: 1.06–1.11 times) and liver condition indices (saithe: 1.4–1.8 times; cod: 2.0–2.8 times) than control fish caught distant from farms. Parasite loads of farm-associated wild fish were modified from control fish, with increased external and decreased internal parasites, however the strong effect of the trophic subsidy overrode any effects of altered loads upon condition. Conclusions and Significance: Proxy measures of fitness provided no evidence that salmon farms function as ecological traps for wild fish. We suggest fish farms may act as population sources for wild fish, provided they are protected from fishing while resident at farms to allow their increased condition to manifest as greater reproductive output.Funding was provided by the Norwegian Research Council Havet og kysten program to the CoastACE project (no: 173384)

Ictioplancton asociado a praderas de Posidonia oceanica durante la época estival en la reserva marina de Tabarca

Ichthyoplankton associated with P. oceanica meadows during the summer season in the Tabarca marine reserveHabitat complexity plays a key role in survival in early stages of fish larvae. We investigated fish larvae assemblage and its relation with P. oceanicaseagrass at the Tabarca Island Marine Reserve. Samples were taken using moored plankton nets at two depths (0 and 2 m from P. oceanica meadow) over five consecutive days in July 2000. Three hundred and fifty¿three larvae were captured. The mostabundant families were Clupeidae (31%), Sparidae (27%), Engraulidae (11%) and Gobiidae (6%). We observed that small fish larvae were able to select nursery areas. We conclude that the P. oceanica leaf canopy is a major factor in structuring the larval fish assemblages of some demersal species

Marine biology, biodiversity and conservation: foreword to the SIEBM 2010 Conference

The SIEBM (Iberian Symposium of Studies on Marine Biology) has a long tradition. The conference was first convened in 1979 and it has since been held approximately biannually. It was originally focused on marine benthos, but two editions ago it was decided to widen its objectives to include other related subjects. The 15th edition was held at the University of Alicante from 6th to 10th September 2010