Diving into the unknown: fourteen new species of haplosclerid sponges (Demospongiae: Haplosclerida) revealed along the Peruvian coast (Southeastern Pacific)

The Peruvian coast is certainly one of the poorest studied areas in the world for marine sponges biodiversity, with only 20 species registered so far from over 2,400 km coastline. In spite of its great species richness worldwide, there is not a single record of Haplosclerida in Peru. Accordingly, in this study we aimed to describe the species belonging to this order present in the relatively recent collections undertaken along the Peruvian coast by two of us (PhW, EH). Here, we describe fourteen new species, provisionally endemic to the Peruvian coast. This finding represents a major addition to the knowledge of the biodiversity of sponges along the Peruvian coast, increasing the list of species known to occur in this area by about 68%. This is also the largest single proposal of new Haplosclerida in over 37 years of sponge taxonomy worldwide. Niphates is for the first time recorded in the Southeastern Pacific, and an identification key to the Haplosclerida from the Peruvian coast is provided. Regarding the distribution of the described species, most of them—except for Chalinula chelysa sp. nov.—have a narrow geographic range, which might indicate their rarity or that the haplosclerid fauna in Peru is still poorly known.

Habitat formed by the invasive macroalga Caulerpa filiformis (Suhr) Hering (Caulerpales, Chlorophyta) alters benthic macroinvertebrate assemblages in Peru

The green macroalga Caulerpa filiformis has been spreading on shallow soft sediment habitats along the Peruvian coast, colonizing previously unvegetated sediments to create monospecific meadows. We examined the nature of the impact of C. filiformis meadows on the density, taxonomic richness and assemblage structure of epifaunal and infaunal benthic macroinvertebrates. Specifically, we tested whether the spread of C. filiformis has resulted in different macroinvertebrate assemblages than those formed by the dominant native macroalgae (i.e., Rhodymenia spp.) and unvegetated sediments. Surveys were undertaken in two bays in each of two locations, in central and southern Peru, during winter 2017 and summer 2018. In general, our results show that macroinvertebrate assemblages were similar across all three habitats, although there were some differences, related to location and season, but with no clear patterns observed. Taxonomic richness and density was generally higher in the vegetated habitats than the unvegetated habitat, and where there were differences between the two vegetated habitats there was no consistent pattern of which habitat supported the highest richness or density. Given invading C. filiformis is primarily colonizing unvegetated habitats it would appear that this species is creating a new niche which supports similar assemblages, but higher taxonomic richness and density than unvegetated habitats. While our study suggests that C. filiformis is having a limited ecological impact we recommend that actions be put in place to limit the spread of this invasive species at the same time as increasing monitoring of the ecological impacts of this species as lags in the ecological impacts of invasive species are common.

Seabird temporal composition, abundance and habitat use in Punta La Metalera (Arequipa, Southern Peru)

Islands, islets, and guano capes provide a unique variety of habitats for seabirds. Their variability determines the structure and dynamics of the community. Studies about the temporal diversity and habitat use of these systems in southern Peru are lacking. The aim of this study was to analyze the abundance, composition, and behavior of seabirds at Punta La Metalera (El Faro) in the province of Islay in the Arequipa region of southern Peru. We recorded a total of 12 species. One of these is endemic to the Peruvian coast (Cinclodes taczanowskii), one is considered in endangered (Spheniscus humboldti), and four have been assigned near threatened status (Phalacrocorax gaimardi, Pelecanus thagus, Sula variegata and Larosterna inca). Some of these birds belong to the guano bird group. Laridae was the most abundant family due to Larosterna inca, which showed the highest number of individuals. Temporal variation showed that species were most abundant in December and January. The habitat was mainly used for resting, preening, and feeding. However, nesting was also recorded for six species. Based on the little information previously available for this region our findings indicate that Punta La Metalera is an important area for the development and reproduction of some of the species recorded.

The Paracas Society of Prehispanic Peru

Paracas society spread over a large geographical area on the southern Peruvian coast between 800 bce and 200 bce. Unlike an “archaeological culture” that has uniform economy, politics, and ideology and is integrated under a single political structure, the Paracas phenomenon was a series of communities adopting different forms of economic and political organizations that were, nevertheless, economically linked and sharing the same religious ideology. The social mechanisms by which all these communities and political entities were linked included exchange, ritual, and religion, which allowed them to share a series of artifacts, social practices, rituals, and religious iconography. In each of the valleys, every entities, or group of communities, had their own architectural and artisanal features and were economically and politically autonomous. The famous archaeological sites associated with Cerro Colorado on the Paracas peninsula seem to have been more than a central place for Paracas society, a social space of integration in which the worship of ancestors stood out as an ideological and religious sustenance that connected communities and elites from different areas of the southern coast of Peru.

Behavior of ITCZ’ second band near the Peruvian coast during the 2017 coastal El Niño

The behavior of the second band of the Intertropical Convergence Zone (ITCZ), near the Peruvian coast during early 2017, is studied, using precipitation, surface winds, sea surface temperature (SST) and atmospheric variables in different isobaric levels. The proposal of a daily index (Ia) to identify, opportunely, the formation of this band and the Lorenz energy terms in the region is also considered. This band was present from late January to early April 2017, associated with an anomalous dipole of sea level pressure between the east and west Oriental Equatorial Pacific, that configured anomalously northerly surface winds and relaxation of southeasterly trade winds near Peru. In medium levels, a zonally-oriented positive mixing ratio anomaly is observed in early March over the ITCZ’s second band, associated with heavy rain systems over the northern Peruvian coastal region. In the same period, positive anomalies of divergence in high tropospheric levels are observed. The daily Ia index allowed an effective detection of the ITCZ’s second band with 11 days prior the maximum coastal precipitation, and the Lorenz energy terms showed kinetic eddies energy (KE) peaks in January and February and a contribution of barotropic instability in equatorial regions.

Diet of the rasptail skate, Rostroraja velezi (Rajiformes: Rajidae), off Piura, Peru

Batoids are among the least studied group of vertebrates and one of the most vulnerable to fishing. The rasptail skate, Rostroraja velezi, is a bycatch species in northern Peru for which there are no studies on its diet. This research aims to document the diet of R. velezi on the northern Peruvian coast and to determine if there are sex-based differences in the diet. A total of 74 R. velezi stomachs were collected, 59 of which had stomach contents. The cumulative prey curve showed reliability in the number of samples collected. According to the prey-specific index of relative importance, diet was dominated by Acanthephyra sp. (31%), other unidentified Caridea (15%), and unidentified teleosts (17%). A low significant difference in diet between sexes was found (R = 0.21, P < 0.01). The trophic position of R. velezi was 3.9 ± 0.7. This species displays bentopelagic feeding behavior and it is a secondary predator in northern Peru.

Stable isotope and fatty acid analyses reveal significant differences in trophic niches of smooth hammerhead Sphyrna zygaena (Carcharhiniformes) among three nursery areas in northern Humboldt Current System

Fishery pressure on nursery areas of smooth hammerhead in northern Peruvian coast have become a serious threat to sustainability of this resource. Even though, some management actions focused on conservation of the smooth hammerhead populations were proposed in recent years, their scientific foundations are often limited, and biomass of smooth hammerhead in Peruvian waters continues to decrease. To inform management and conservation, this study aims to evaluate the trophic niche of smooth hammerhead juveniles from three nursery areas in the northern Peruvian coast using stable isotope and fatty acid analyses. First, we compared the environmental characteristics of each nursery area (i.e., sea surface temperature and chlorophyll-a concentration) and concluded that nursery areas differed significantly and consistently in sea surface temperature. Subsequently, we evaluated isotopic composition of carbon and nitrogen and fatty acid profiles of muscle and liver tissues collected from juvenile smooth hammerhead from each nursery area. We found that juvenile smooth hammerhead captured in San José were enriched in heavier 13C and 15N isotopes compared to those captured in Máncora and Salaverry. Furthermore, the broadest isotopic niches were observed in juveniles from Máncora, whereas isotopic niches of juveniles from Salaverry and San José were narrower. This difference is primarily driven by the Humboldt Current System and associated upwelling of cold and nutrient rich water that drives increased primary production in San José and, to a less extent, in Salaverry. Compared to smooth hammerhead juveniles from Máncora, those from San José and Salaverry were characterised by higher essential fatty acid concentrations related to pelagic and migratory prey. We conclude that smooth hammerhead juveniles from three nursery areas in the northern Peruvian coast differ significantly in their trophic niches. Thus, management and conservation efforts should consider each nursery area as a unique juvenile stock associated with a unique ecosystem and recognize the dependence of smooth hammerhead recruitment in San José and Salaverry on the productivity driven by the Humboldt Current System.

Species Delimitation of Southeast Pacific Angel Sharks (Squatina spp.) Reveals Hidden Diversity through DNA Barcoding

Angel sharks are distributed worldwide in tropical to subtropical waters. Across the Eastern Pacific Ocean (EPO), two valid species are reported: The Pacific angelshark Squatina californica and the Chilean angelshark Squatina armata; however, there is still uncertainty about their geographic distribution, mainly along the northern Peru coast where the species have been reported to be sympatric. The aim of this study is to describe the genetic differences between the genus Squatina from the EPO, including samples from northern Peru, and using DNA barcoding and three species delimitation models: Poisson tree processes (PTP) model, Bayesian implementation of the PTP (bPTP) model and the general mixed Yule coalescent (GMYC) model. The three approaches summarized 19 nominal Squatina species in 23 consensus Molecular Taxonomic Units (MOTU). Only 16 of them were in accordance with taxonomic identifications. From the EPO, four Squatina MOTUs were identified, one from North America (S. californica USA/Mexico) and three sampled in northern Peru, S. californica Peru, S. armata and Squatina sp. (a potential new species). This study contributes to the management and conservation policies of angel sharks in Peru, suggesting the presence of an undescribed species inhabiting the northern Peruvian coast. The use of molecular approaches, such as DNA barcoding, has the potential to quickly flag undescribed species in poorly studied regions, including the Southeast Pacific, within groups of ecologically and economically important groups like angel sharks.

Inter-decadal variations of surface winds off Peruvian coast

&lt;p&gt;The Peruvian upwelling system (PUS) is the most productive marine ecosystem among the Eastern Boundary upwelling Systems (EBUS). The trade wind system drives a nearly continuous upwelling which is subjected to variations on a wide range of times scales. The wind forced upwelling controls crucially the nutrient supply to the euphotic surface layer and thus, the overall productivity of the system.&lt;/p&gt;&lt;p&gt;Using long term data from ERA5 (1979-2019) the wind forcing in the PUS was analyzed to obtain information about long term trends in the mean state and its variability.&lt;/p&gt;&lt;p&gt;Beside the strong annual cycle, the wind forcing is dominated by interannual and a long term interdecadal oscillation.&lt;/p&gt;&lt;p&gt;The interannual fluctuations with a period of 2-5 years are related to the known events of El Ni&amp;#241;o and La Ni&amp;#241;a. The wind anomaly shows a good correlation with Oceanic Ni&amp;#241;o Index (ONI). Interdecadal variation of wind depict a main period of 15-20 years whit negative anomaly values from 1979 to 1996, and positive anomaly values for 1996-2014. These long term variations can be attributed to the Interdecadal Pacific Oscillations (IPO). The spatial distribution of wind stress along the Peruvian coast is not uniform. The highest values are observed in Lima-Marcona area (12&amp;#186;-15.4&amp;#186; S) while it decreases sharply southward and gradually northward. Additionally the coastal upwelling area is modulated locally by the coupling of wind and SST.&lt;/p&gt;