The role of synchronized swimming as affiliative and anti-predatory behavior in long-finned pilot whales

Synchronized swimming in cetaceans has been hypothesized to play a role in affiliative processes as well as anti-predatory responses. We compared observed variation in synchronized swimming at two research sites in relation to disturbance exposure to test these two hypotheses. This study describes and quantifies pair synchronization in long-finned pilot whales at the Strait of Gibraltar, Spain and Cape Breton, Canada. Synchronization differed depending on the behavioral state and the response is different in the two sites leading to the conclusion that environment can shape the occurrence and magnitude of certain behaviors. We also analyzed intra-population variations in synchronization among 4 social units of Pilot whales in the Strait of Gibraltar and the results of this study confirmed the affiliative role of synchronization and highlighted an influence of disturbance on synchronization. We can conclude that synchronization is a common behavior in long-finned pilot whales that allow for close proximity and rapid coordinated response of individuals, with the multiple functions of showing affiliation and reacting to disturbance.     

Demographic parameters of a free-ranging deep-diving cetacean,the long-finned pilot whale

Demographic parameters provide baselines to estimate future population trajectories which can then be used in management decisions. The aim here was to estimate demographic parameters of long-finned pilot whale (Globicephala melas) from the Strait of Gibraltar by fitting mark-recapture models to photo-identification data of primary and secondary marked individuals. These parameters were used to forecast the future population trajectories in a population viability analysis (PVA) given different scenarios of demographic rates. Survival rate increased with age from 0.629, 95% CI [0.409, 0.805] for calves, 0.869, 95% CI [0.758, 0.934] for juveniles, to 0.972, 95% CI [0.953, 0.983] for adults. A preliminary mean observed interval of viable calves was 4.5 years. The PVA estimated the population would persist over 100 years with a 100% probability for all scenarios except those with lower 95% CI survival values, for which the probability of extinction reached 100%. Population growth rate was negative in all scenarios except those with 95% CI upper survival values. Interbirth interval and juvenile survival were found most influential and depended on the correct identification of secondary marked (e.g., calves and juveniles) individuals on a long-term basis. This population was found in a precarious state prior to a morbillivirus outbreak that might even more endanger its long-term viability.     

Repeated call sequences and behavioural context in long-finned pilot whales off Cape Breton,Nova Scotia,Canada

Repeated calls are part of the vocal repertoire of a diverse array of species, often presented in sequences that take time and effort on the part of the signal producer. Rhythmic repeated call sequences make up a significant portion of long-finned pilot whale (Globicephala melas) vocal production, yet the function of these sequences has not been investigated until now. In this study, we explored the relationship between behavioural context and the presence of these vocal sequences using recordings of a population of pilot whales found off Cape Breton, Nova Scotia, Canada. We used a binomial logit-link generalized linear model to look for possible predictors of the presence of repeated call sequences. They were more common in recordings of socializing whales than in those of whales in other behavioural states, and least common in resting whales. These vocal repetitions were also more common with larger group size. These results suggest that sequences function in maintaining contact and cohesion within this social species, possibly also serving in individual or group identification. The context of repeated call sequences indicate that they are not primarily mother–calf interactions, as they are heard just as commonly from groups without young. Future studies of pilot whale repeated call sequences should include individual-level behaviour and detailed acoustic calling context.     

Small-scale spatial distributions of long-finned pilot whales change over time,but foraging hot spots are consistent: Significance for marine wildlife tourism management

Data collected opportunistically aboard marine wildlife tourism vessels are an inexpensive source of spatial information on the target species. Although these data are often challenging to analyze, they can be used to monitor spatiotemporal changes in species distribution and behavior. Disruptions from whale-watching vessels to behaviors such as foraging can be particularly harmful to cetaceans, but impacts could be reduced if areas essential for these sensitive behaviors are identified. We used data collected onboard whale-watching vessels to explore space-use patterns in long-finned pilot whales (Globicephala melas) off northern Cape Breton Island, Canada, an area where tourism is essential. Encounters with pilot whales between 2011–2016 occurred twice as far offshore than during 2003–2006 and 2008, and foraging activity decreased. Despite the changes in distribution and activity budgets, we identified two hot spots of foraging activity that persisted through time. These identified foraging hot spots comprised only a small proportion (20 km² ) of the range used by whale-watching vessels. Adaptive local management (e.g., voluntary codes of conduct) focused on limiting interactions in these energetically important areas may help reduce any potential impacts from whale-watching and promote the continued viability of the whale population and the tourism industry that relies on it.     

Phylogeography of the lacertid lizard, Psammodromus algirus, in Iberia and across the Strait of Gibraltar

Aim  To determine genetic substructuring within the lacertid lizard Psammodromus algirus . To compare levels of variation across a geological barrier, the Strait of Gibraltar, and to compare this against the known age of the barrier using a molecular clock hypothesis. To compare the effect of the barrier within this species with previously published data from other organisms.
Location  The Iberian Peninsula and North Africa.
Methods  Partial sequences from the mitochondrial cytochrome b , 12S rRNA and 16S rRNA genes were obtained from 101 specimens belonging to the subfamily Gallotiinae and used in this study. The data set was aligned using C lustal X and phylogenetic trees produced using both maximum-parsimony and maximum-likelihood methods. Maximum likelihood estimates of divergence times for the combined data set (12S + 16S + cytochrome b ) were obtained after discovery of lineage rate constancy across the tree using a likelihood ratio test.
Results  Psammodromus algirus contains divergent eastern and western mtDNA clades within the Iberian Peninsula. The western clade has northern and southern lineages in Iberia and one in North Africa. This phylogeographical pattern indicates that the lizard invaded North Africa after the opening of the Strait, presumably by natural rafting.
Main conclusions  As in several other species, current patterns of genetic diversity within P. algirus are not directly related to the opening of the Strait of Gibraltar. Widespread sampling on both sides of the barrier is necessary to determine its effect on species in this area accurately.     

Complex biogeographical distribution of genetic variation within Podarcis wall lizards across the Strait of Gibraltar

Abstract Aim To examine the effect of a known geological barrier on genetic variation within a wall lizard species complex. Location The Iberian Peninsula and North Africa. Methods Sequencing of partial 12S rRNA and cytochrome b mtDNA. Results The current distribution of genetic variability is not related to the opening of the Strait of Gibraltar. Conclusions Podarcis hispanica in North Africa is probably a species complex. The Strait of Gibraltar should not be used as a known barrier to gene flow in other land based organisms without careful sampling to test for multiple crossings since its formation.     

Survival and abundance of short‐finned pilot whales in the archipelago of Madeira,NE Atlantic

Estimates of population parameters for the short‐finned pilot whale, Globicephala macrorhynchus, are scarce in literature, contributing to an International Union for Conservation of Nature (IUCN) status of Data Deficient. In this study, photo‐identification data collected over 7 yr from Madeira were used to estimate for the first time survivorship, capture probability, and abundance in this species using mark‐recapture methodology. The Cormack‐Jolly‐Seber model estimated that the adult island‐associated (i.e., resident and regular visitor) whales had a constant survival rate of 0.960 (95% CI: 0.853–0.990) and an annual capture probability varying between 0.372 (CI: 0.178–0.619) and 0.843 (CI: 0.619–0.947). A parameterization of the Jolly‐Seber model estimated that 140 island‐associated whales (CI: 131–151) used the area throughout the course of the study. Based on a closed population model, the most precise (lower CV) annual estimate of the total number of pilot whales using the southern and eastern waters of Madeira (~900 km²) in a 3 mo period covering summer/autumn was 334 animals (CI: 260–437). No trend was observed. Despite including biases, the approach used in this study provided plausible estimates of population parameters, which can contribute to the regional conservation strategies.     

The Strait of Gibraltar as a major biogeographic barrier in Mediterranean conifers: a comparative phylogeographic survey

The Strait of Gibraltar (SG) is reputed for being both a bridge and a geographic barrier to biological exchanges between Europe and Africa. Major genetic breaks associated with this strait have been identified in various taxa, but it is unknown whether these disjunctions have been produced simultaneously or by independent biogeographic processes. Here, the genetic structure of five conifers distributed on both sides of the SG was investigated using mitochondrial (nad1 b/c, nad5-1, nad5-4 and nad7-1) and chloroplast (Pt1254, Pt15169, Pt30204, Pt36480, Pt71936 and Pt87268) DNA markers. The distribution of genetic variation was partially congruent between types of markers within the same species. Across taxa, there was a significant overlapping between the SG and the genetic breaks detected, especially for the four Tertiary species surveyed (Abies pinsapo complex, Pinus nigra, Pinus pinaster and Taxus baccata). For most of these taxa, the divergence of populations across the SG could date back to long before the Pleistocene glaciations. However, their strongly different cpDNA G(ST) and R(ST) values point out that they have had dissimilar population histories, which might include contrasting amounts of pollen-driven gene flow since their initial establishment in the region. The fifth species, Pinus halepensis, was genetically depauperated and homogenous on both sides of the SG. A further analysis of nuclear DNA sequences with coalescent-based isolation with migration models suggests a Pleistocene divergence of P. halepensis populations across the SG, which is in sharp contrast with the pre-Pleistocene divergence dates obtained for P. pinaster. Altogether, these results indicate that the genetic breaks observed across this putative biogeographical barrier have been produced by independent evolutionary processes related to the biological history of each individual species instead of a common vicariant phenomenon.     

Two new species of Caprella (Crustacea:Amphipoda:Caprellidea) collected from sandy bottoms in the Strait of Gibraltar

Two new species of the genus Caprella (Crustacea:Amphipoda:Caprellidea) are described based on specimens collected from the Strait of Gibraltar (Southern Spain and Northern Africa). Both species were found living in sandy bottoms. Caprella pseudorapax n. sp. is very close to the species C. rapax (Mayer, 1890) and C. lilliput (Krapp-Schickel & Ruffo, 1987). Caprella sabulensis n. sp. resembles C. cavediniae (Krapp-Schickel & Vader, 1998).     

Long-term social structure of long-finned pilot whales (<Emphasis Type="Italic">Globicephala melas</Emphasis>) in the Strait of Gibraltar

The Strait of Gibraltar is inhabited by around 216 pilot whales, which are present all year round, and nothing is known about their social structure. The aim of this study is to analyse the inter-individual association patterns within this pilot whales community to (1) provide an insight on their long-term social system and (2) to assess the relationship between sexes within this social system. Between 1999 and 2006, 23,004 km was sampled in the Strait of Gibraltar, and 4,887 images of dorsal fins of pilot whales were taken from 226 groups. The sex of 56 of the individuals could be determined genetically. The strength of the behavioural relationships between dyads of individuals was calculated, and the temporal aspects of the social structure were evaluated, showing in a non-random social structure made by constant companions. The preferred associations between individuals consisted in associations of males–females. Eight long-term units could be found with different degrees of association rates. Consequently, we propose that, in the Strait, the pilot whales exhibit a hierarchical social system composed of a population encompassing several clans of pilot whales each containing several pods. Pods will then be formed by several line units, similar to killer whale matrilineal units.     

Short-finned pilot whales in the South China Sea: Insights into regional distribution,movement pattern,and habitat characteristics

Little scientific knowledge is available for short-finned pilot whales in the South China Sea (SCS). Here, we integrated historical records, ship-based observation, and satellite-tagging data to investigate ecological and behavioral characteristics of pilot whales in the SCS. Historical records since the 1990s showed the widespread spatial occurrence of pilot whales along the coastal SCS, suggesting that the species may inhabit this region. During our dedicated ship-based surveys (2019–2022) in the SCS, 19 groups of pilot whales were encountered in Xisha-Zhongsha waters, which supported the hypothesis inferred from historical data. We believe that Xisha-Zhongsha waters are important habitats for pilot whales, demonstrated by the large group size (M = 44.7 ± 42.4 SD individuals), the high proportion of recorded maternal groups (17/19), mixed-species associations, and deep-water habitat characteristics. During field surveys, we conducted satellite-tagging experiments on two adult pilot whales, with tracking periods of 35 and 13 days, respectively. Satellite-tracking data provided evidence of possible residency of the tagged whales, as both displayed overlapping ranges and nondirectional movement. This research provides preliminary baseline data on occurrence, distribution, movement, habitat use, and likely residency of pilot whales in the SCS, which can facilitate future research and conservation effort.     

Residency and abundance of sperm whales (Physeter macrocephalus) in Nemuro Strait,Hokkaido, Japan

We examined the trend in residence patterns and abundance of male sperm whales in Nemuro Strait, Japan, based on long-term photo-identification (1,513 survey days, total 2,969 photos) between 2006 and 2017. A total of 225 unique individuals were identified during this study, with an average of 36 (SE = 2.55) new individuals identified in each season. The model chosen by maximum likelihood suggests that residence time around Nemuro Strait is 769 (SE = 372.4) days, with individuals staying in the strait about 48 days (SE = 8.36) per year. While the migration patterns of male sperm whales visiting this area are still unclear, these findings along with previous studies suggest that males move from one breeding area to another neighboring area every several weeks, shifting their home ranges gradually over a period of a few years. The abundance of sperm whales in Nemuro Strait varied greatly from year to year; from 28 (95%CI: 24–44) in 2015 and (95%CI: 22–48) in 2016 to 66 (95%CI: 57–84) in 2011. This study provides important knowledge of abundance and residency for Nemuro Strait, information which will contribute to further research on the social structure and movement pattern of male sperm whales.     

Survival,site fidelity,and the population dynamics of Piping Plovers in Saskatchewan

ABSTRACT To conserve threatened species, managers require predictions about the effects of natural and anthropogenic factors on population growth that in turn require accurate estimates of survival, birth, and dispersal rates, and their correlation with natural and anthropogenic factors. For Piping Plovers (Charadrius melodus), fledging rate is often more amenable to management than adult survival, and population models can be used to estimate the productivity (young produced per breeding female) necessary to maintain or increase populations for given levels of survival. We estimated true survival and site fidelity of adult and subadult (from fledging to second year) Piping Plovers breeding in Saskatchewan using mark‐resight data from 2002 to 2009. By estimating true survival rather than apparent survival (which is confounded with permanent emigration), we were able to provide more accurate projections of population trends. Average adult and subadult survival rates during our study were 0.80 and 0.57, respectively. Adult survival declined over time, possibly due in part to the loss of one breeding site to flooding. Average adult and subadult site fidelity were 0.86 and 0.46, respectively. Adult site fidelity declined during our study at two study sites, most strongly at the flooded site. Male and female Piping Plovers had similar survival rates, but males had greater site fidelity than females in some years. Based on our survival estimates, productivity needed for a stationary population was 0.75, a benchmark used for plover management on the Atlantic Coast, but not previously estimated for Prairie Canada. In stochastic simulations incorporating literature‐based variation in survival rates, productivity needed for a stationary population increased to 0.86, still lower than that previously estimated for western populations. Mean productivity for our study sites ranged from 0.87 to 0.96 fledged young per pair. Our results suggest that fledging rates of Piping Plovers in Saskatchewan were sufficient to ensure a stationary or increasing population during our study period. However, large‐scale habitat changes such as drought or anthropogenic flooding may lead to dispersal of breeding adults and possibly mortality that will increase the fledging rate needed for a stationary population.     

Population trends for humpback whales (Megaptera novaeangliae) foraging in the Francisco Coloane Coastal‐Marine Protected Area,Magellan Strait,Chile

In 2003 a feeding aggregation of southeastern Pacific humpback whales (Megaptera novaeangliae) was reported in the Magellan Strait. While Chile established its first marine national park in the Strait to protect humpback whale habitat, fatal ship strikes remain a concern because of overlap with a busy shipping lane. To better understand population risk, we estimated abundance and survival for this population using Bayesian robust‐design mark‐recapture models fit to photographic data from 2004 to 2016. Overall, the model estimated a total of 204 whales (95% CI: 199–210) during the last 12 yr, and 93 (95% CI: 86–100) in the 2016/2017 austral summer. The population grew at 2.3% (CI: 2.1%–3.1%), an annual increase of two whales. Annual survival (including calves) was estimated at 0.892 (CI: 0.871–0.910). Our results corroborate a persistent feeding population, but one that is increasing relatively slowly. Owing to its vulnerability stemming from its small size, coupled with significant overlap with a busy shipping lane, we argue this subpopulation is at significant risk from ship strikes and may be one of the few populations where anthropogenic mortalities could regulate population dynamics. We therefore encourage continued monitoring via photographic mark‐resighting surveys, and analyses explicitly investigating potential population‐level ship strike effects.     

Short‐finned pilot whales (Globicephala macrorhynchus) of the Mariana Archipelago: Individual affiliations,movements, and spatial use

Little is known about short‐finned pilot whales (Globicephala macrorhynchus) in the western North Pacific outside of Japanese coastal waters. To expand understanding of short‐finned pilot whale ecology in the region, we conducted small‐boat surveys in 2010?2016 within the Mariana Archipelago to investigate individual associations, movements, spatial use, and dive behavior of short‐finned pilot whales. We collected genetic, photo‐identification, and satellite‐tag data and identified 191 distinctive individuals. A preliminary social network diagram of photo‐cataloged individuals revealed a main cluster that comprised 82% of individuals, representing all five mitochondrial DNA haplotypes identified within the population. Kernel density estimates for tagged short‐finned pilot whales (n = 11) during summer were used to identify areas with the highest probability of use (10% probability density contour), core area (50%) and home range (95%). The area with highest probability of use by short‐finned pilot whales was off the northwest side of Guam. Satellite tag data also suggest that some individuals are island‐associated year‐round. Data from five location‐dive tags demonstrated that the short‐finned pilot whales dove more often to intermediate depths at twilight and night, suggesting they may target prey that forage on the deep scattering layer as it migrates to and from the surface.     

Reproductive phenology,growth and primary production of Phyllariopsis purpurascens (Phyllariaceae,Phaeophyta) from the Straits of Gibraltar

Two populations of Phyllariopsis purpurascens from the Straits of Gibraltar area were investigated during 1990 and 1991. This area has very strong currents (～2·5 m s^-1 at spring tide). The first sporophytes (less than 0·5 cm in length) were observed in April; they disappeared after the first storm period in October. The estimated number of spores produced in an unilocular sporangium was 64. The fertility period started in May and continued until October, but the maximum sorus surface area (27%) was reached in September. The maximum sporangial density was 1476±236 mm^-2. The slow development of fertility and its correlation with the seasonal increase in temperature suggest that sporangial development is controlled by temperature and not by photoperiod. The drag effect produced by the strong currents (at spring tides and storm periods) is sufficient to break adult plants (with 0·01 m² in surface intercepting the current). At the beginning of the sporophytic production cycle (210 days), the meristematic zone produces more tissue for blade growth than for stipe growth. Holdfast growth occurs in the first 3 months. The mortality was 90% for sporophytes 0–10 cm in length, and decreased to ～50% in adult plants. One cohort in the cycle has been identified. The net primary production (calculated by the graphic model of Allen) was 0·04 g dry weight m^-2·day^-1 from April to October (210 days). The production is among the lowest values estimated for seaweeds.     

Site fidelity,residency, and abundance of bottlenose dolphins (Tursiops sp.) in Adelaide's coastal waters,South Australia

Little is known about the ecology and behavior of southern Australian bottlenose dolphins (Tursiops sp.). This hinders assessment of their conservation status and informed decision‐making concerning their management. We used boat‐based surveys and photo‐identification data to investigate site fidelity, residency patterns, and the abundance of southern Australian bottlenose dolphins in Adelaide's coastal waters. Sighting rates and site fidelity varied amongst individuals, and agglomerative hierarchical cluster analysis led to the categorization of individuals into one of three groups: occasional visitors, seasonal residents, or year‐round residents. Lagged identification rates indicated that these dolphins used the study area regularly from year to year following a model of emigration and reimmigration. Abundance estimates obtained from multisample closed capture‐recapture models ranged from 95 individuals (SE ± 45.20) in winter 2013 to 239 (SE ± 54.91) in summer 2014. The varying levels of site fidelity and residency, and the relatively high number of dolphins found throughout the study area highlights the Adelaide metropolitan coast as an important habitat for bottlenose dolphins. As these dolphins also appear to spend considerable time outside the study area, future research, conservation, and management efforts on this population must take into account anthropogenic activities within Adelaide's coastal waters and their adjacencies.     

Population trends of Rooks Corvus frugilegus in Spain and the importance of refuse tips

Anthropogenic food from refuse tips can affect population dynamics in birds, especially gulls, but the evidence is mostly circumstantial. We combine analyses of long-term population data and natural experiments to show a positive effect of refuse tips on the growth of the Spanish breeding population of Rooks Corvus frugilegus . In this isolated population of around 2000 breeding pairs, monitored since 1976, birds in colonies less than 10 km from tips fed largely on refuse, particularly during periods of lowest natural food availability. Three lines of evidence support the hypothesis that the supply of refuse influenced breeding numbers, suggesting that this population is limited by food: 1) between 1976 and 2003, the two population nuclei that had access to tips increased 2.1 and 3.7 times more than that without a tip nearby; 2) annual colony growth between 1996 and 2003 was strongly correlated with the availability of tips when other potentially important variables were taken into account; 3) the number of breeding pairs in refuse-foraging colonies declined rapidly after the closure of the local tip and recovered only when a supply of refuse was restored. The effect of tips on colony growth was stronger when the availability of natural foraging habitat around the colonies was low, suggesting that anthropogenic food acts as a buffer against shortage of natural food. Artificial food supplementation may be an effective tool to increase the breeding population of target species, especially those facing a reduction of their foraging habitats. The potential effects on bird species of Directive 1999/31/CE, which is enforcing a massive closure of tips in Europe, are discussed.