Shallow Rocky Shores Research Articles

Exploration of Patellidae from Coastal Waters of Ambon Island, Indonesia

Patellidae are gastropods that live in intertidal zones and sublittoral zones of shallow rocky shores because Patellidae are usually attached to boulders. Patellidae belongs to the order Archaeogastropoda and generally only has two genera, namely Cellana and Patella. Patellidae are also found in the waters of Ambon Island, namely in the Hukurila Village and Allang Village. This study aims to determine the type, morphometrics, density, and proximate levels of Patellidae in the waters of Ambon Island. Samples were taken using purposive sampling with cruising methods. The Patellidae are attached to the substrate. Samples from two locations were taken and put into plastic, and then the type and morphometrics were identified at the Basic Biology Laboratory of the Faculty of Teacher Training and Education, Pattimura University. Proximate levels were conducted at the Basic Chemistry Laboratory, Faculty of Mathematics and Natural Sciences, Pattimura University. This research was conducted from October 15, 2022, to November 15, 2022. Based on the results, two species of the Patellidae family were found in Ambon Island, namely C. testudinaria and P. flexuosa. The results of the calculation of morphometric Patellidae in the Waters of Ambon Island showed that the species C. testudinaria in the Waters of Hukurila Village has a larger morphometric characteristic size compared to the species C. testudinaria and P. flexuosa in the Waters of Allang Village. More individuals of P. flexuosa species were found in Alang village than C. testudinaria species, while many C. testudinaria species were found in Hukurila village. Based on the proximate analysis results, Patellidae from the waters of Ambon Island have nutritious and good nutritional content to be used as food ingredients.

Diel activity patterns of rocky shore macroinvertebrates in the northern Baltic Sea

Marine invertebrates on rocky shores form dynamic communities in time and space. Invertebrates constitute important links in the food chain and in biogeochemical cycles and are thus essential for functioning ecosystems. Species can be diurnal or nocturnal, and adaptions can be explained by predation pressure and resource availability. Contrary to terrestrial species, marine invertebrates are less specialised in single hosts and can, when needed, switch habitats, a trait that favours survival, growth, and reproduction.Variation in movement patterns of macroinvertebrates was studied on the northwestern Åland Islands (Åland Sea) to assess changes in activity on a diel timescale along the summer season. Two methods were used to collect representative samples of both swimming and non-swimming species. The pool of macroinvertebrate taxa in the study area was controlled for by sampling ambient macroalgae-associated fauna. Results show that all swimming and epifaunal mobile macroinvertebrate taxa move actively either in the free water body or along the sea floor within a 24-h period. A preference towards nocturnal activity could be observed as the total abundance of macroinvertebrates was higher during the night. Mean taxonomic richness was somewhat higher at night for the swimming macroinvertebrates. The community structure of mobile macroinvertebrates changed within a 24-h period as, e.g. Palaemon spp. and P. ulvae were more prevalent, and larger individuals were generally more active at night. The methods used were suitable for describing the activity patterns of macroinvertebrates on shallow rocky shores, and the results are essential for understanding the temporal dynamics of complex littoral rocky shore communities.

Relationship between Fucus coverage and algal diversity in the northern Baltic Sea

The canopy-forming brown macroalgae Fucus vesiculosus and Fucus radicans (Fucus) are the largest habitat-building species on rocky shores of the northern Baltic Sea. While their role on the diversity of invertebrate fauna is well documented, there is little information on their importance for the diversity of associated macroalgal species. We used comprehensive mapping data from the Finnish marine area (divided into four sea areas) to test the relationship between Fucus coverage and algal biodiversity (number of taxonomic units, Shannon-Wiener diversity index H′ and Pielou's evenness J'). To account for environmental variation, depth, wave exposure, Secchi depth and salinity were included as covariates. Examination of the algal communities highlighted a similar pool of taxonomic units across sea areas in shallow (0–4 m) rocky shores, with the two filamentous algal species Pylaiella littoralis and Ectocarpus siliculosus combined as one unit being the most common taxon. The Shannon-Wiener diversity index was highest in sites with Fucus coverage between 25% and 75%, while evenness increased with Fucus coverage. We did not detect any effects of Fucus coverage on the number of taxonomic units, which was rather affected by environmental parameters (depth, Secchi depth and salinity). The results show that Fucus, depending on its coverage, both competes with and facilitates the macroalgal community. Based on extensive data, we show how Fucus coverage relates to the diversity of the surrounding algal communities, further improving our understanding of factors that control biodiversity on shallow rocky shores in the northern Baltic Sea.

The invasive seaweed Asparagopsis taxiformis erodes the habitat structure and biodiversity of native algal forests in the Mediterranean Sea

Invasive seaweeds are listed among the most relevant threats to marine ecosystems worldwide. Biodiversity hotspots, such as the Mediterranean Sea, are facing multiple invasions and are expected to be severely affected by the introduction of new non-native seaweeds in the near future. In this study, we evaluated the consequences of the shift from the native Ericaria brachycarpa to the invasive Asparagopsis taxiformis habitat on the shallow rocky shores of Favignana Island (Egadi Islands, MPA, Sicily, Italy). We compared algal biomass and species composition and structure of the associated epifaunal assemblages in homogenous and mixed stands of E. brachycarpa and A. taxiformis. The results showed that the biomass of primary producers is reduced by 90% in the A. taxiformis invaded habitat compared to the E. brachycarpa native habitat. The structure of the epifaunal assemblages displayed significant variations among homogenous and mixed stands. The abundance, species richness and Shannon-Wiener diversity index of the epifaunal assemblages decreased by 89%, 78% and 40%, respectively, from homogenous stands of the native E. brachycarpa to the invasive A. taxiformis. Seaweed biomass was the structural attribute better explaining the variation in epifaunal abundance, species richness and diversity. Overall, our results suggest that the shift from E. brachycarpa to A. taxiformis habitat would drastically erode the biomass of primary producers and the associated biodiversity. We hypothesize that a complete shift from native to invasive seaweeds could ultimately lead to bottom-up effects on rocky shore habitats, with negative consequences for the ecosystem structure, functioning, and the services provided.

Marine ecosystem restoration in a changing ocean

Multiple human impacts on natural ecosystems cause ongoing widespread habitat loss, with consequent decline of biodiversity and ecosystem services. Seas and oceans, the largest biomes of the biosphere, show increasing numbers of degraded habitats. Ecological restoration offers a major tool to reverse this trend and recover biodiversity, along with human health and well‐being. The United Nations Decade on Ecosystem Restoration promotes global‐scale restoration of degraded habitats and we can exploit lessons learned from terrestrial restoration projects to improve and accelerate marine ecosystem restoration science, practice, and policy. Nonetheless, major differences in land and sea limit direct transfer of terrestrial approaches. Limited ecosystem baselines, greater stochasticity and connectivity, longer timescales needed for effective restoration, associated high costs and advanced technologies required to access and intervene in marine environments (especially in the deep sea), and difficulty in scaling up restoration efforts all hinder the effectiveness and expansion of marine ecosystem restoration. Pilot actions in European waters over ca 5 years in the EU‐funded MERCES consortium (Marine Ecosystem Restoration in Changing European Seas) have identified and developed new, promising tools and strategies to catalyze restoration actions, including engagement of funding organizations, governmental bodies, scientists, and citizens. We are now better positioned to implement restoration actions on a wide range of protected, vulnerable, and critical marine habitats, including seagrass meadows, algal forests, shallow rocky shore, and even some deep‐sea habitats. Outcomes from the MERCES project support future restoration initiatives by demonstrating restoration potential in the marine environment.

Massive decline of <em>Cystoseira abies-marina</em> forests in Gran Canaria Island (Canary Islands, eastern Atlantic)

Brown macroalgae within the genus Cystoseira are some of the most relevant “ecosystem-engineers” found throughout the Mediterranean and the adjacent Atlantic coasts. Cystoseira-dominated assemblages are sensitive to anthropogenic pressures, and historical declines have been reported from some regions. In particular, Cystoseira abies-marina, thriving on shallow rocky shores, is a key species for the ecosystems of the Canary Islands. In this work, we analyse changes in the distribution and extension of C. abies-marina in the last decades on the island of Gran Canaria. This alga dominated the shallow rocky shores of the entire island in the 1980s; a continuous belt extended along 120.5 km of the coastline and occupied 928 ha. In the first decade of the 21st century, fragmented populations were found along 52.2 km of the coastline and occupied 12.6 ha. Today, this species is found along 37.8 km of the coastline and occupies only 7.4 ha, mainly as scattered patches. This regression has been drastic around the whole island, even in areas with low anthropogenic pressure; the magnitude of the decline over time and the intensity of local human impacts have not shown a significant correlation. This study highlights a real need to implement conservation and restoration policies for C. abies-marina in this region.

Phylogenetic relationships of Mediterranean and North-East Atlantic Cantharidinae and notes on Stomatellinae (Vetigastropoda: Trochidae)

The subfamily Cantharidinae Gray, 1857 (Trochoidea: Trochidae) includes 23 recognized genera and over 200 known living species. These marine top shell snails are microphagous grazers that generally live in shallow rocky shores and in macroalgae and seagrass beds of sub-tropical and temperate waters from the Central and Western Indo-Pacific biogeographic regions to the Mediterranean Sea and the Eastern Atlantic Ocean. Recent molecular phylogenetic studies revising the family Trochidae supported the monophyly of the subfamily Cantharidinae and its sister group relationship to the subfamily Stomatellinae. These studies and others has thus far mostly focused on Indo-Pacific members of the subfamily Cantharidinae whereas here, we investigated phylogenetic relationships among their counterparts from the Mediterranean Sea and the North-eastern (NE) Atlantic Ocean including 33 species of genera Gibbula, Jujubinus, Phorcus, Clelandella, and Callumbonella. The Mediterranean and NE Atlantic taxa were supplemented with 30 Indo-Pacific Cantharidinae species plus 19 members of the sister group subfamily Stomatellinae. Phylogenetic trees were constructed using Bayesian inference and maximum likelihood with two datasets comprised of partial sequences of four or six mitochondrial (cox1, rrnL, rrnS, and cob) and nuclear (28S rRNA and histone H3) genes. A clade comprised of all Mediterranean and NE Atlantic taxa was recovered with high support, but its sister group among the Indo-Pacific lineages could not be determined with confidence (although the assignment of “Trochus” kotschyi to Priotrochus could be rejected). Within the Mediterranean and NE Atlantic clade, genera Phorcus and Jujubinus were recovered as reciprocally monophyletic, and the deep-sea genera Clelandella and Callumbonella were placed with high support as sister to Jujubinus. However, the genus Gibbula as currently defined was not monophyletic and constituent species were divided into three major clades and two independent lineages. Phylogenetic relationships among Phorcus, Jujubinus (plus Clelandella and Callumbonella), and the different clades of Gibbula were not fully resolved but received higher support in the phylogenetic analyses based on six genes. A first approach to resolve phylogenetic relationships within Stomatellinae was conducted showing that the diversity of the subfamily is highly underestimated at present, and that Calliotrochus is possibly a member of this subfamily. A chronogram was reconstructed using an uncorrelated relaxed lognormal molecular clock and the origin of the Mediterranean and NE Atlantic clade was dated right after the Azolla phase in the Middle Eocene about 48 million years ago whereas diversification of major clades (genera) followed the eastern closure of the Tethys Ocean in the Middle Miocene about 14 million years ago.

Community structure of shallow rocky shore fish in a tropical bay of the southwestern Atlantic

Abstract Southwestern Atlantic Ocean rocky shores sustain important reef fish communities. However, those communities in tropical regions are not well understood, especially in Brazil. In this present article we assess community parameters of reef fishes such as composition, trophic organization and their relationships with physical and biological factors on four tropical rocky shores in Todos os Santos Bay, southwestern Atlantic. During six months, a total of 80 visual censuses were performed, in which 3,582 fish belonging to 76 species were recorded. Territorial herbivorous fish and turf algae were dominant at all the sites. The spatial variability of fish community structure was related to the benthic cover composition and depth. The high abundance of territorial herbivores and mobile invertebrate feeders could be associated with high levels of turf cover, low wave exposure and shallow waters. Moreover, this fact could be a consequence of the low density of roving herbivores and large carnivores probably due to the pressure of intense fishing activity. Thus complementary studies are needed to evaluate the actual conservation status of these rocky shore reefs, singularly located habitats connecting inner and outer reefs in Todos os Santos Bay.

Spatial pattern of hydrolittoral rock encrusting assemblages along the salinity gradient of the Baltic Sea

Abstract This study compared the diversity parameters and structures of encrusting assemblages in two habitats situated at two levels of shallow rocky shore: hydrolittoral and littoral along the Baltic Sea system. We investigated the variability and level of distinctiveness of the hydrolittoral encrusting fauna based on species biodiversity and distribution, and compared these features with those of communities inhabiting the adjacent shallow littoral zone (3-m depth). Structural similarities and differences between the encrusting assemblages from adjacent hydrolittoral and littoral zones were studied within 14 locations distributed along the northern coastline of the Baltic Sea. Multivariate analysis indicates that salinity had the greatest influence on the structure of the investigated assemblages. Most of the observed hydrolittoral assemblages contained the same species as the littoral zone. This result indicated a shared common species pool with similar large-scale patterns of species distributions with some variability in the dominating species between zones. The similarity between species composition of the hydrolittoral and littoral assemblages decreased with increase of salinity. Additionally, with higher species richness and the occurrence of marine specialists adapted to hydrolittoral conditions, the role of the rock size in the frequency of species occurrence and assemblage diversity was less significant.

Contribution to the knowledge of cotylean flatworms (Turbellaria, Polycladida) from Iranian coasts: Introducing a new species, with remarks on new records.

Very little information is available regarding marine free-living flatworms not only from Iran, but throughout the countries surrounding the Persian Gulf and the Gulf of Oman. The present study first introduces a new euryleptid species, and then reports four pseudocerotid polyclads which inhabit Iranian shallow rocky shores of the Persian Gulf and the Gulf of Oman. Maritigrella makranica sp. nov. is characterized dorsally by a medial cream or white reticulated appearance containing pale orange spots in a honeycomb pattern, a distinct orange submarginal band around the entire body margin and between the marginal tentacles, black spots scattered around mid-dorsal surface, becoming more sparse on raised median region and towards body margin, surrounded by a dark-grey halo around the body midline and orange-black halo towards margin. Three of the four pseudocerotids species belonging to the genera Pseudobiceros Faubel, 1984; Pseudoceros Lang, 1884; and Thysanozoon Grube, 1840, are new records for the studied areas, while the other has been reported in the Persian Gulf previously. Comments on Iranian species are provided and associations of flatworms with ascidians and sponges were observed.

Description of two new Discocelis species (Polycladida: Acotylea: Discocelidae) from the Persian Gulf with a review of the genus.

Two new polyclad species, from northern intertidal zone and shallow rocky shores of the Persian Gulf, Discocelispersica sp. nov. and Discocelis hollemani sp. nov., are described. D. persica possesses a thick and broadly oval body tapering somewhat posteriorly, without any obvious color pattern; with marginal eyes extended around the anterior margin of the body; cerebral eyes forming two clusters, each further subdivided into anterior and posterior groups, about 100 eyespots at the anterior group and 55 eyespots at the posterior groups; mouth at the posterior end of the pharynx; male atrium with three to four distinct lobes, with numerous prostatoid organs of two distinct sizes, without villus-like projections; and with a horseshoe-shaped Lang's vesicle. D. hollemani characterized by a thick and broadly oval body, not tapering antro-posteriorly, without any obvious color pattern; marginal eyes extended to the vicinity of the posterior end of pharynx; the cerebral eyes forming two clusters, each further subdivided into anterior and posterior groups in relation to the cerebral organ, about 50 eyespots at the anterior group and 20 eyespots at the posterior groups; mouth at the posterior end of the pharynx; the male atrium with two distinct lobes, with numerous prostatoids of two distinct sizes and different contents; villus-like projections absent, and with a horseshoe-shaped Lang's vesicle.

Three Pseudocerotidae species (Platyhelminthes, Polycladida, Cotylea) from the Argentinean coast

Three species of flatworms, Phrikoceros mopsus (Marcus, 1952), Thysanozoon brocchii (Risso, 1818) and Thysanozoon mirtae sp. nov., are described from specimens collected from shallow rocky shores of Mar del Plata harbour, in the southwestern Atlantic. P. mopsus had been described as living in the coasts of Brazil and southern Patagonia. T. brocchii has a more extensive known distribution, from the Mediterranean to the coasts of Brazil and the Argentinean Patagonia. Their morphological variation is here recorded and discussed. Thysanozoon mirtae sp. nov. is characterized by its colour pattern, colourless tentacles, and the presence of well developed spermiducal vesicles and a strong parenchymatic musculature.

Entomacrodus solus, a new species of blenny (Perciformes, Blenniidae) from the Red Sea

Entomacrodus solus, new species, is described on the basis of 35 specimens collected by J.E. Randall on a shallow rocky shore at the end of a mangrove channel at Ras Mohammed, Red Sea. The new species belongs to the Nigricans Species Group, which is distinguished from all other blennies in having about the medial third of the ventral margin of the upper lip entire and the lateral thirds crenulate. Within the group, now consisting of 11 species, the new species is distinguished by having only single pores at each preopercular pore position, typically three predorsal commissural pores, and small white spots on lips, head and body. Entomacrodus solus is the only species of the circumtropical genus Entomacrodus known from the Red Sea.

Two new Pleioplana species (Platyhelminthes, Polycladida, Acotylea) from Turkey

Two new species of flatworms, Pleioplana bosphorensis sp. nov. and Pleioplana Okusi sp. nov., Acotylea, Polycladida, are described from the shallow rocky shores of the Turkish Straits System, northwestern Turkey. Both species are characterized by a prostatic vesicle of atomata-type, stylet and Lang's vesicle. Pleioplana bosphorensis possesses a body of fleshy consistency and without tentacles, with spermiducal bulbs; elongated seminal vesicle and rounded prostatic vesicle with four tubular chambers and a conical, strong, large and straight stylet. Pleioplana Okusi has a translucent body, tentacular knobs, large seminal vesicle, elongated prostatic vesicle with six tubular chambers, and a long slender slightly curved stylet.

SPATIAL AND TEMPORAL VARIABILITY OF THE OPISTHOBRANCH MOLLUSCS OF PORT LLIGAT BAY, CATALONIA, NE SPAIN

Studies on the community structure and population dynamics of opisthobranchs are very scarce. This is probably related to the fact that the number of specimens is usually low and field work is difficult in the habitat where they occur. The spatial and temporal variability of the opisthobranch molluscs inhabiting Sant Antoni beach in Port Lligat Bay (a shallow rocky shore near Cadaqués, Costa Brava, NE Spain) were studied quantitatively from February 1997 to January 1999. This shore was chosen because in previous qualitative studies relatively large populations of some species were found there. Samples were taken monthly during the two years and the sampling consisted of 5 stations along two transects (one perpendicular to the shore, the other one in parallel). At each station, 3 samples were taken (3 independent square meters). In every square, all the stones were lifted, both sides examined, and all the opisthobranchs present were measured and left undisturbed. Only unidentified animals were collected for classification. Egg masses were also measured when present. In this quantitative study, a total of 138 specimens, belonging to 26 species were found. The nudibranch Aldisa banyulensis was the most abundant species, with higher numbers of specimens at the end of winter and spring, and the largest specimens found during spring time. Egg masses of A. banyulensis were found in late spring-early summer during the first year. The nudibranch Dendrodoris limbata also was abundant and present through the year. The largest specimens of D. limbata were found during winter and spring. Abundance and species richness of opisthobranchs was significantly different at the five stations studied, probably due to contrasting physical conditions and prey abundance. Qualitative and quantitative studies provide similar values of species richness but different abundances. In total, 45 opisthobranch species are now reported for Sant Antoni beach.

Coexistence of permanently territorial cichlids of the genus Petrochromis through male-mating attack

Coexistence mechanisms of permanently territorial fishes proposed hitherto have been mainly based on interspecific competition. To test the hypothesis of the coexistence through male-mating aggression (Kohda, 1995a), spacing patterns of feeding territories of three coexisting herbivorous cichlids, Petrochromis polyodon, P. trewavasae and P. famula, were investigated in a homogeneous habitat at a shallow rocky shore in Lake Tanganyika. All three species maintained individual feeding territories that were defended against both conspecifics and congenerics and rarely overlapped either intra- or interspecifically. Territories of three species were scattered and covered almost all rocky bottoms. Territorial attacks usually occurred near the border of feeding territories. But male P. polyodon, the largest and socially most dominant fish, attacked conspecific males far beyond their feeding territories, which were widely separated. Removal of some territory owners suggested that such attacks result in the separate distribution of male P. polyodon territories. The interstitial space between P. polyodon feeding territories resulting from their mating aggression can be occupied by subordinate congeneric fishes. Male-mating attack of dominant males of Petrochromis will facilitate the coexistence of other congeners.