José M. Guerra-García

Assessing habitat use of the endangered marine mollusc Patella ferruginea (Gastropoda, Patellidae) in northern Africa: preliminary results and implications for conservation

Abstract The limpet Patella ferruginea Gmelin, 1791, endemic to the Mediterranean, is the most endangered marine species on the list of the European Council Directive 92/43/EEC on the Conservation of Natural Habitat of Wild Fauna and Flora (1992). Its Mediterranean range has progressively contracted to a few restricted areas and the species is now threatened with extinction. Seventeen stations were sampled along the littoral zone on the coast of Ceuta, North Africa, for quantifying environmental factors (water movement, siltation and suspended solids), and 70 transects were selected for P. ferruginea sampling. The study revealed the presence of a well-established population of P. ferruginea with values of density and size of 0.67 individuals m−1 ±0.96 and 48.94 mm±11.61 respectively (mean±standard error of mean). The biggest densities of P. ferruginea were found inside the harbour of Ceuta. The limpets were more abundant on artificial harbour stones than on natural rocky shores, and the areas under the highest human pressure were characterised by the lowest densities and the smallest specimens probably due mainly to the predation for food and fishing. Human pressure is probably the main contributing factor to the currently endangered status of P. ferruginea. Programmes of environmental education to avoid its collection for fishing, food or for fun as decorative objects should be conducted, and further experimental studies dealing with the reproductive biology of this species are needed to properly assess the future programmes of conservation.

Habitat use of the caprellidea (crustacea: Amphipoda) from ceuta, North Africa

Abstract Although the caprellid amphipods are very important in marine ecosystems, knowledge of their ecology is scarce. During a sampling programme in North Africa (1998–2000) a total of 22 caprellid species belonging to 5 genera were collected. The habitat use was investigated for all of them. The composition of the caprellidean communities was clearly different between exposed and sheltered areas. Caprella danilevskii, C. fretensis, C. grandimana, C. liparotensis and C. penantis were found in exposed areas, while C. dilatata, C. hirsuta, C. takeuchii and Pedoculina garciagomezi preferred sheltered areas. The species of the former group were morphologically characterised by large size, elongate body somites, a short basis of gnathopod 2 and short pereopods. This morphology enables the caprellids to develop a “parallel” posture attaching strongly to the substrate in areas subject to heavy wave action or strong currents. The smaller species, such as C. cavediniae, C. ceutae, C. erethizon, C. monai, C. santosrosai and C. tuberculata were restricted to deeper coraligen areas, living on hydroids instead of algae. Caprella acanthifera, Phtisica marina and Pseudoprotella phasma were habitat and substrate cosmopolitan. An up-to-date record of caprellid-invertebrate associations is also given.

Sewage pollution and extinction risk: an endangered limpet as a bioindicator?

The mollusc Patella ferruginea, endemic to the Mediterranean, is the most endangered marine species on the list of the European Council Directive 92/43/EEC and it is under serious risk of extinction. In spite of the low abundances and restricted distribution of this limpet, important populations have been found in the harbour of Ceuta, north Africa. The main objective of the present study was to characterise, for the first time, the effects of sewage pollution on P. ferruginea and related limpet species, and to evaluate the potential value of these limpet assemblages as bioindicators, using univariate and multivariate analyses. Physicochemical parameters and limpets were sampled in nine stations located at 0, 1, 2, 4, 8, 16, 32, 64 and 128 m away from the discharge point of a sewage effluent in Ceuta harbour. The stations closer to the outfall (0, 1, 2, 4 and 8) were characterised by higher values of turbidity, phosphate and ammonia in the water column, and organic matter, faecal coliforms and faecal Streptococci in sediments. A total of six limpet species were found and studied (Patella ferruginea, P. caerulea, P. nigra, P. rustica, P. ulyssiponensis and Siphonaria pectinata); the number of limpet species increased with increasing distance from the outfall, while diversity and evenness reached the highest values at intermediate sites. Siphonaria pectinata and P. caerulea were the most resistant and abundant species, while P. ferruginea was the most sensitive species to sewage pollution, only found at stations from 32 to 128 m. The distribution of this endangered limpet seems mainly affected by the pollution gradient, and not by the competition with the remaining limpets. The results of this study should be taken into account in future programmes of management and conservation of P. ferruginea.

Is the north side of the Strait of Gibraltar more diverse than the south side? A case study using the intertidal peracarids (Crustacea: Malacostraca) associated to the seaweed Corallina elongata

The objectives of this study were to describe the peracaridean fauna associated to the algae Corallina elongata from the Strait of Gibraltar, and explore possible biodiversity and biogeographical patterns of variation along the north–south and Atlantic–Mediterranean axes across the Strait of Gibraltar. Twenty-five stations were selected along the north and south coasts of the Strait to cover the broadest possible range of human pressure and environmental conditions, including both natural rocky shores and artificial breakwaters. The alga Corallina elongata was selected as substrate, and the peracaridean crustaceans were identified to species level and classified in geographical distribution groups. Univariate and multivariate analyses were conducted to explore and confirm patterns of variation. Forty peracarid species were collected, most of them with an Atlantic–Mediterranean distribution (67%) with only the gammarid Parhyale eburnea , being an endemic Mediterranean species. The most common species collected during the present study were the gammarids Hyale stebbingi, Jassa marmorata, Stenothoe monoculoides and Ampithoe spp., the caprellids Caprella grandimana and C. penantis , the isopod Ischyromene lacazei and the tanaid Tanais dulongi . The number of species per station and the diversity index were significantly higher in the stations located along the north side of the Strait of Gibraltar. However, the two-way ANOVA discarded differences between north and south due to the type of substrate (natural versus artificial) and degree of human pressure. Based on peracaridean assemblages, the Strait of Gibraltar behaves as a whole and homogeneous region, with a very similar faunal composition in all stations and there is not a clear gradient of species substitution from the Mediterranean to the Atlantic stations. Provided that we selected the same substrate in all stations, and that statistical analyses revealed that differences between north and south stations were not due to environmental factors such as anthropogenic stress or type of substrate, we should look to historical biogeographical reasons to explain the higher diversity in the north side of the Strait of Gibraltar.

Aspects of reproduction and their implications for the conservation of the endangered limpet, Patella ferruginea

Summary The protandric limpet, Patella ferruginea G., is the most endangered marine species in the Western Mediterranean and is at serious risk of extinction. Nevertheless, its biology and ecology are little known. In the present work, several reproductive aspects are studied. Recruitment take place in June and the largest individuals are the most scarce. The sex ratio is slanted towards the largest sizes, and the species seems to show sex change at sizes from 60 mm upwards, although males can be observed up to 80 mm. There is no correlation between size of oocytes and shell length; however, the larger females contribute greatly to the reproductive event, with high fecundity and GSI values. The mean diameter of oocytes was observed to be 149.78 μm, whereas the heads of spermatozoa were 3.78 μm long. The results of the present study increase the maximum length for males by double that cited in previous literature and highlight the importance of strictly protecting females (i.e., most of the largest individuals, >60 mm), since their population percentage is very low, in order to develop adequate strategies to preserve the species.

Crustachan Assemblages and Sediment Pollution in an Exceptional Case Study: A Harbour with Two Opposing Entrances

[Harbours are usually provided with only one entrance and lack channels. They are enclosed areas with a low rate of water renewal, a high sedimentation rate, and high concentrations of pollutants in the sediments, and the soft-bottom communities are characterized by low species richness. The harbour of Ceuta, North Africa, presents a particular structure, since it is provided with two opposing entrances and a channel, which increases the water renewal across the middle of the harbour. We selected the soft-bottom crustacean community to explore its value as a bioindicator of physicochemical variables in the sediment and to test the environmental implications of the channel of the harbour on macrofaunal assemblages. Twenty-one stations were selected and 27 variables were measured in the sediment of each station. Multivariate analyses were much more sensitive than univariate techniques to discriminate between internal and external stations of Ceuta harbour. The pollution and depth gradients were the main factors to determine species ordination. The tanaid, Apseudes latreillii and the amphipods, Corophium runcicorne , C. sextonae , Pariambus typicus, Leucothoe lilljeborgii, and Corophium sextonae were dominant at the internal stations, whereas the tanaid, Leptochelia dubia and the amphipod, Siphonoecetes dellavallei were more abundant at the external stations. The crustacean species richness in sediments inside the harbour (59 species) was significantly higher than in conventional harbours, mainly due to the presence of the channel. The construction of open-water channels as a remedial action towards pollution is thus suggested for future design of harbours, wherever possible. Generalmente, los puertos presentan una unica entrada y carecen de canales. Son areas cerradas con poca renovacion de agua, tasa elevada de sedimentacion, concentraciones altas de contaminantes en los sedimentos y baja riqueza especifica en las comunidades de fondo blando. El puerto de Ceuta, Norte de Africa, presenta una estructura particular ya que esta provisto de dos entradas opuestas y un canal que incrementa la renovacion del agua en el puerto. Se ha seleccionado la comunidad de crustaceos para explorar su valor como bioindicadora de las variables fisicoquimicas en el sedimento y para estudiar las implicaciones ambientales del canal del puerto sobre la macrofauna. Se seleccionaron 21 estaciones y se midieron 27 variables en el sedimento de cada estacion. Los analisis multivariantes fueron mucho mas sensibles que las tecnicas univariantes en la discriminacion entre estaciones internas y externas del puerto de Ceuta. Los gradientes de contaminacion y profundidad fueron los factores principales que determinaron la ordenacion de las especies. El tanaidaceo Apseudes latreillii y los anfipodos Corophium runcicorne, C. sextonae, Pariambus typicus, Leucothoe lilljeborgii y Corophium sextonae fueron dominantes en las estaciones internas, mientras que el tanaidaceo Leptochelia dubia, y el anfipodo Siphonoecetes dellavallei fueron mas abundantes en las estaciones externas. El numero de especies de crustaceos en sedimentos del interior del puerto (59 especies) fue significativamente mayor que en puertos convencionales, debido principalmente a la presencia del canal. De este modo, se sugiere en la medida de lo posible la construccion de canales en el diseno futuro de los puertos para disminuir los efectos de la contaminacion., Harbours are usually provided with only one entrance and lack channels. They are enclosed areas with a low rate of water renewal, a high sedimentation rate, and high concentrations of pollutants in the sediments, and the soft-bottom communities are characterized by low species richness. The harbour of Ceuta, North Africa, presents a particular structure, since it is provided with two opposing entrances and a channel, which increases the water renewal across the middle of the harbour. We selected the soft-bottom crustacean community to explore its value as a bioindicator of physicochemical variables in the sediment and to test the environmental implications of the channel of the harbour on macrofaunal assemblages. Twenty-one stations were selected and 27 variables were measured in the sediment of each station. Multivariate analyses were much more sensitive than univariate techniques to discriminate between internal and external stations of Ceuta harbour. The pollution and depth gradients were the main factors to determine species ordination. The tanaid, Apseudes latreillii and the amphipods, Corophium runcicorne , C. sextonae , Pariambus typicus, Leucothoe lilljeborgii, and Corophium sextonae were dominant at the internal stations, whereas the tanaid, Leptochelia dubia and the amphipod, Siphonoecetes dellavallei were more abundant at the external stations. The crustacean species richness in sediments inside the harbour (59 species) was significantly higher than in conventional harbours, mainly due to the presence of the channel. The construction of open-water channels as a remedial action towards pollution is thus suggested for future design of harbours, wherever possible. Generalmente, los puertos presentan una unica entrada y carecen de canales. Son areas cerradas con poca renovacion de agua, tasa elevada de sedimentacion, concentraciones altas de contaminantes en los sedimentos y baja riqueza especifica en las comunidades de fondo blando. El puerto de Ceuta, Norte de Africa, presenta una estructura particular ya que esta provisto de dos entradas opuestas y un canal que incrementa la renovacion del agua en el puerto. Se ha seleccionado la comunidad de crustaceos para explorar su valor como bioindicadora de las variables fisicoquimicas en el sedimento y para estudiar las implicaciones ambientales del canal del puerto sobre la macrofauna. Se seleccionaron 21 estaciones y se midieron 27 variables en el sedimento de cada estacion. Los analisis multivariantes fueron mucho mas sensibles que las tecnicas univariantes en la discriminacion entre estaciones internas y externas del puerto de Ceuta. Los gradientes de contaminacion y profundidad fueron los factores principales que determinaron la ordenacion de las especies. El tanaidaceo Apseudes latreillii y los anfipodos Corophium runcicorne, C. sextonae, Pariambus typicus, Leucothoe lilljeborgii y Corophium sextonae fueron dominantes en las estaciones internas, mientras que el tanaidaceo Leptochelia dubia, y el anfipodo Siphonoecetes dellavallei fueron mas abundantes en las estaciones externas. El numero de especies de crustaceos en sedimentos del interior del puerto (59 especies) fue significativamente mayor que en puertos convencionales, debido principalmente a la presencia del canal. De este modo, se sugiere en la medida de lo posible la construccion de canales en el diseno futuro de los puertos para disminuir los efectos de la contaminacion.]

The Caprellidea (Crustacea: Amphipoda) from Tasmania

The taxonomy of the Caprellidea from the Tasmanian coast is reviewed with data on species composition and biogeographical characteristics. Four new species, Caprella edgari n. sp., Hircella inermis n. sp., Orthoprotella tuberculata n. sp. and Paraproto tasmaniensis n. sp. are described, and detailed descriptions of Caprella acanthogaster Mayer, 1890, Orthoprotella tasmaniensis Guiler, 1954 and Paraproto spinosa (Haswell, 1885) are provided. Lateral view figures of the 18 species found in Tasmanian waters until now, with a key to species level, are also given. The species diversity of littoral caprellids from Tasmania is considerably high when compared with other regions of similar latitude in the southern hemisphere, probably due to the warm effect of the East Australian current passing down towards the east coast of Tasmania. This fact, with previous studies on the low concentrations of dissolved nutrients in rivers and dark tannin-stained waters on the west coast, could result in species richness and abundance being clearly higher on the east coast of Tasmania.

La fauna de caprélidos (Crustacea: Amphipoda: Caprellidea) de la costa de Coquimbo, centro-norte de Chile, con una clave taxonómica para la identificación de las especies

Caprellids are abundant in many littoral habitats ofthe marine environment. Nevertheless, this group of amphipods has been scarcely studied along the coast of Chile. The study ofthe Caprellidea is particular! y difficult dueto the high degree of intra-specific morphological variability and the fact that literature and specimens from Museums are not easily located. The objective of the present study was to pro vide the taxonomical tools to identify the most common caprellid species from northem-central Chile. Severa! habitats were examined (buoys, boulders, algal/seagrass beds) and six caprellid species were found: Caprellina longicollis (Nicolet, 1849), Cap re/la equilibra S ay, 1818, C. scaura Templeton, 1836, C. verrucosa Boeck, 1871; Deutella venenosa Mayer, 1890 and Paracaprella pusilla Mayer, 1890. Cap re/la scaura, C. verrucosa and D. venenosa were most abundant among algae, hydrozoans and bryozoans growing on buoys. Cap re/la equilibra, al so present on buoys, was most abundant undemeath boulders in exposedrocky intertidal zones, where additionally D. venenosa and P. pusilla were found. Caprella scaura was dominant in plant beds above sandy subtidal bottom, especially among the alga Gracilaria chilensis and the seagrass Heterozostera tasmanica, where it occurred together with Caprellina longicollis. Paracaprella pusilla represents a new citation for the pacific coasts of S-America, being a new record for Chile. The species D. venenosa, which was recorded for the first time since the original description by Mayer in the year 1890, is considered an endemic species from the central coast of Chile.

The Caprellidea (Crustacea, Amphipoda) from Western Australia and Northern Territory, Australia

The caprellidean fauna of Western Australia and Northern Territory, Australia, is investigated here. The study reports 26 species in 19 genera. Six new species (Aciconula australiensis n. sp., Caprella traudlae n. sp., Pseudaeginella vaderi n. sp., Orthoprotella nana n. sp., Pseudoprotella soela n. sp. and Pseudoprotomima grandimana n. sp.) are described as new for Science. Lateral view figures of all the species, together with a key to species level, are also provided.

Responses of the endangered limpet Patella ferruginea to reintroduction under different environmental conditions: survival, growth rates and life‐history

The mollusc Patella ferruginea, endemic to the Mediterranean, is the most endangered marine species of the list of the European Council Directive 92/43/EEC and it is presently under serious risk of extinction. Survival, growth rates and life‐history of this species were studied for the first time in this species. A total of 570 specimens (420 introduced in a new habitat and 150 as control) were marked and monitored over a three‐year period. Growth rates observed were mainly related to the availability of microalgal food. The mortality rate of transplanted specimens was high (50% mortality immediately after transplant). Seasonality in growth rates was observed in both control and transplanted specimens, with greater growth rates detected in spring‐summer (warm season) than in autumn‐winter (cold season). Smaller specimens of P. ferruginea had the greatest growth rates in comparison with the bigger specimens, therefore the potential ability to adapt in a new habitat was higher for small specimens immediately after removal. An elevated growth rate (appearing as a light‐ring in the border of the shell) was detected immediately after translocation, following which growth rate progressively stabilized over time. Using differential equations and the von Bertalanffy model, the longevity of P. ferruginea was estimated to range between 8.89 and 35.72 years depending on the environment. Transplantation should not be considered as a conservation measure given the elevated mortality rate.