Responses of wintering humpback whales (Megaptera novaeangliae) to playback of recordings of winter and summer vocalizations and of synthetic sound

Summary Three natural sounds and one synthetic sound were played back to humpback whales during their 1985 and 1986 winter residency in Hawaiian waters. Playback was conducted from a vessel positioned within visual range of an elevated shorestation equipped with a high-precision surveyor's theodolite, used to determine the positions and movements of observed whale and of the playback vessel. A playback session consisted of 20 min of pretest observation with the vessel in place and underwater speaker deployed, followed by a 20-min test phase during which sound, or a blank tape control, was introduced. A total of 143 playback sessions, involving a total of 338 pods (a single whale or a group of whales), were completed over the two winter seasons. The major response observed during playback was a rapid approach to the playback vessel, characterized in some cases by velocities up to 9 km/h and approaches to within 50 m or less. Whales approaching were mainly singletons and, secondly, apparent adult pairs. No cow-calf pair ever approached. The approach was selective: 21.6% of targeted pods approached in response to a feeding sound recorded in summer feeding grounds in Alaska; 8.3% approached in response to social sounds recorded in the Hawaiian winter grounds in the presence of large surface-active pods; 3.4% responded to playback of winter song; and 4.1% responded to playback of synthetic sound. There were no approach responses to the blank tape control. Singing whales have been identified as males by many researchers. Data from Alaska suggested that the feeding sound was produced by a female; data from Hawaii suggests that the social sounds were produced by males. The different rates of response were attributed to the behavior of sexually active males seeking to affiliate with sexually mature females. Although a female may be present in pods producing social sounds, the presence of multiple males exhibiting aggression may inhibit the approach of other males. Song did not serve as an attractant for females, as measured by direct approach, but may still serve as a basis for female choice.     

Sighting characteristics and photo-identification of Cuvier’s beaked whales (<Emphasis Type="Italic">Ziphius cavirostris</Emphasis>) near San Clemente Island,California: a key area for beaked whales and the military?

The relationship between beaked whales and certain anthropogenic sounds remains poorly understood and of great interest. Although Cuvier’s beaked whales (Ziphius cavirostris) are widely distributed, little is known of their behavior and population structure throughout much of their range. We conducted a series of five combined visual-acoustic marine mammal surveys from 2006 to 2008 in the southern San Nicolas Basin, a site of frequent naval activity off the southern California coast, west of San Clemente Island. The study area was defined by a 1,800 km² array of 88 bottom-mounted hydrophones at depths up to 1,850 m. The array was used to vector visual observers toward vocalizing marine mammal species. Thirty-seven groups of Cuvier’s beaked whales were encountered during the study period. The overall encounter rate was one group for every 21.0 h of survey effort, and was as high as one group per 10.2 h of effort during the October 2007 survey. Whales were encountered in the deepest portion of the study area, at a mean bottom depth of 1,580 m (SD 138). The average group size was 3.8 individuals (SD 2.4), which was higher than has been reported from other studies of this species. Twenty-four groups were observed over multiple surfacings (median = 4 surfacings, range 2–15). The mean encounter duration of extended sightings was 104 min (SD 98, range 12–466 min) and the mean distance moved over the course of sightings was 1.66 km (SD 1.56, range 0.08–6.65 km). Temporal surfacing patterns during extended encounters were similar to dive behavior described from Cuvier’s beaked whales carrying time-depth recording tags. Seventy-eight photographic identifications were made of 58 unique individuals, for an overall resighting rate of 0.26. Whales were sighted on up to 4 days, with duration from first to last sighting spanning 2–79 days. For those whales sighted on subsequent days, the mean distance between subsequent sightings was 8.6 km (SD 7.9). Individuals resighted over 2–3 days were usually in association with previous group members. Approximately one-third of groups contained more than one adult male, and many of the repeated associations involved adult males. These observations suggest the basin west of San Clemente Island may be an important region for Cuvier’s beaked whales, and also one which affords an unusual opportunity to collect detailed data on this species. Given its status as an active military range, it can also provide the ability to monitor the behavior of individuals in the presence of naval sonar, a critical step in the management of this and other beaked whale populations worldwide.     

Interactions between singing Hawaiian humpback whales and conspecifics nearby

Summary Interactions of singing humpback whales, Megaptera novaeangliae, with conspecifics nearly were studied during the breeding season off the west coast of Maui, Hawaii. On 35 occasions singing humpbacks were followed by boats (Table 1). The movement patterns of these singing whales and other conspecifics nearby were recorded by observers on land using a theodolite.Thirteen of 35 singers stopped singing and joined with nonsinging whales either simultaneously or within a few minutes after ceasing to sing. Another 15 also stopped singing while under observation and were not seen to join with another whale, but all singing whales that joined with other whales stopped singing. Singing whales often pursue nonsinging whales, while nonsinging whales usually turn away from singers (Figs. 4, 5).When a singer joined with a female and calf unaccompanied by another adult, behavior tentatively associated with courtship and mating was observed (Fig. 7). Such behavior also occurred during several interactions between singers and individuals of unknown sex. Aggressive behavior was observed during three interactions between singers and individuals of unknown sex (Fig. 4) and it predominated whenever more than one adult accompanied a cow and calf. During the other occasions when a singer joined another whale, we could not determine the nature of the interaction. Many times the singers and joiner would surface together only once and would then separate. However, on several occasions the singer and joiner would remain together for as long as we could follow them, up to 1.5 h.The roles of singer and joiner can be interchangeable. For instance, on two occasions a singer joined with a whale that either had been singing or started singing later in the day (Fig. 3). Furthermore, on several occasions, a nonsinging whale appeared to displace the singer. Individual singing humpbacks are not strictly territorial, although singers appear to avoid other singers.As the breeding season progressed, singers sang for longer periods of time (Fig. 2). In addition, the probability of a whale joining with the singer decreased by 42% from the first half of the observation period to the second half. Furthermore, this increase in duration of song bouts occurred during that section of the season when female reproductive activity as measured by rate of ovulation is reported to be decreasing in other areas.Our observations support the hypothesis that humpback song plays a reproductive role similar to that of bird song. Humpbacks sing only during the breeding season. If, as seems likely, most singing humpbacks are male, then singing humpbacks probably communicate their species, sex, location, readiness to mate with females, and readiness to engage in agonistic behavior with other whales.     

Quantifying Loss of Acoustic Communication Space for Right Whales in and around a U.S. National Marine Sanctuary

The effects of chronic exposure to increasing levels of human‐induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human‐induced sound on contact‐calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (～10,000 km²) and time period (peak feeding time). We used an array of temporary, bottom‐mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel‐tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal‐to‐noise ratio and the assumed recognition differential) for contact‐calling right whales was negative (?1 dB) under current ambient noise levels and was further reduced (?2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63–67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10‐min period. These results highlight the limitations of exposure‐threshold (i.e., dose‐response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide‐ranging noise effects in emerging ocean‐planning forums that seek to improve management of cumulative effects of noise on marine species and their habitats. Cuantificación de la Pérdida de Espacio de Comunicación Acústica para Ballenas Francas Dentro y Alrededor de un Santuario Marino Nacional en E. U. A.     

Whistle communication in mammal-eating killer whales (Orcinus orca): further evidence for acoustic divergence between ecotypes

Public signaling plays an important role in territorial and sexual displays in animals; however, in certain situations, it is advantageous to keep signaling private to prevent eavesdropping by unintended receivers. In the northeastern Pacific, two populations of killer whales (Orcinus orca), fish-eating “resident” killer whales and mammal-eating “transient” killer whales, share the same habitat. Previous studies have shown that residents use whistles as private signals during close-range communication, where they probably serve to coordinate behavioral interactions. Here, we investigated the whistling behavior of mammal-eating killer whales, and, based on divergent social structures and social behaviors between residents and transients, we predicted to find differences in both whistle usage and whistle parameters. Our results show that, like resident killer whales, transients produce both variable and stereotyped whistles. However, clear differences in whistle parameters between ecotypes show that the whistle repertoire of mammal-eating killer whales is clearly distinct from and less complex than that of fish-eating killer whales. Furthermore, mammal-eating killer whales only produce whistles during “milling after kill” and “surface-active” behaviors, but are almost completely silent during all other activities. Nonetheless, whistles of transient killer whales may still serve a role similar to that of resident killer whales. Mammal-eating killer whales seem to be under strong selection to keep their communication private from potential prey (whose hearing ranges overlap with that of killer whales), and they appear to accomplish this mainly by restricting vocal activity rather than by changes in whistle parameters.     

Abundance of the New Zealand subantarctic southern right whale population estimated from photo-identification and genotype mark-recapture

The abundance of New Zealand subantarctic southern right whales (Eubalaena australis) was estimated for the first time using mark-recapture methods based on photo-identification and microsatellite genotyping (13 loci). Individual identification photographs of 383 whales and microsatellite genotypes of 235 whales were collected during annual austral winter field surveys from 1995 to 1998. Given the 4-year survey period and lack of geographic and demographic closure, we estimated super-population abundance using the POPAN Jolly-Seber model implemented in the software programme MARK. Models with constant survivorship but time-varying capture probability and probability of entry into the population were the most suitable due to the survey design. This provided estimates of abundance in 1998 of 908 non-calf whales (95% C.L. = 755, 1,123) for the photo-identification and 910 non-calf whales (95% C.L. = 641, 1,354) for the microsatellite genotype data sets. The current estimate of 900 whales may represent less than 5% of the pre-whaling abundance in New Zealand waters.     

Effectiveness of Voluntary Conservation Agreements: Case Study of Endangered Whales and Commercial Whale Watching

Abstract: The use of voluntary approaches to achieve conservation goals is becoming increasingly popular. Nevertheless, few researchers have quantitatively evaluated their efficacy. In 1998 industry, government agencies, and nongovernmental organizations established a voluntary conservation program for whale watching in the northeast region of the United States, with the intent to avoid collisions with and harassment of endangered whales by commercial and recreational whale‐watching vessels. One important aspect of the program was the establishment of 3 speed zones within specific distances of whales. We wanted to determine the level of compliance with this aspect of the program to gauge its efficacy and gain insights into the effectiveness of voluntary measures as a conservation tool. Inconspicuous observers accompanied 46 commercial whale‐watching trips from 12 companies in 2003 (n= 35) and 2004 (n= 11). During each trip, vessel position and speed were collected at 5‐second intervals with a GPS receiver. Binoculars with internal laser rangefinders and digital compasses were used to record range and bearing to sighted whales. We mapped whale locations with ArcGIS. We created speed‐zone buffers around sighted whales and overlaid them with vessel‐track and speed data to evaluate compliance. Speeds in excess of those recommended by the program were considered noncompliant. We judged the magnitude of noncompliance by comparing a vessel's maximum speed within a zone to its maximum recorded trip speed. The level of noncompliance was high (mean 0.78; company range 0.74–0.88), some companies were more compliant than others (p= 0.02), noncompliance was significantly higher in zones farther from whales (p < 0.001), and operators approached the maximum speed capabilities of their vessel in all zones. The voluntary conservation program did not achieve the goal of substantially limiting vessel speed near whales. Our results support the need for conservation programs to have quantifiable metrics and frequent evaluation to ensure efficacy.     

Comparative study of crustacean larval photoresponses

Ovigerous females of four brachyuran (Cancer gracilis, Lophopanopeus bellus bellus, Hemigrapsus oregonensis and Scyra acutiforns) and two anomuran (Pagurus beringanus and P. granosimanus) species, which live as adults in coastal areas, were collected near Friday Harbor, Washington, USA, in 1985, and spectral sensitivity and phototactic pattern of their larvae were measured. Responses were compared with previous measurements on estuarine species to determine whether responsiveness varies with adult habitat. Estuarine and coastal species have similar photoresponses. Spectral sensitivity of the test brachyran species had two maxima, one near 400 to 420 nm and another around 500 nm. The anomuran species were similar, but had an additional peak in the region of 580 to 620 nm. This sensitivity is adapted to daytime light conditions in the adult environment, and available spectra at the time of larval movement during diel vertical migration. Upon light adaptation and stimulation with a narrow light field, all six species showed positive phototaxis to high light intensities and a pronounced negative response to low intensities. Only the negative response will occur in natural underwater light conditions, and it is part of a predator-avoidance shadow-response which operates in areas of higher light intensity. The same phototactic pattern is observed in all species when darkadapted except H. oregonensis. If nocturnal vertical migration occurs, this negative response may be responsible for the descent at sunrise and depth maintenance during the day.     

Observations of dugong reproductive behavior in Trang Province,Thailand: further evidence of intraspecific variation in dugong behavior

The seagrass beds at Muk Island and Talibong Island in Thailand are important areas for dugong (Dugong dugon) feeding and reproduction. We used opportunistic observations during aerial surveys to investigate dugong mating behavior in shallow water areas near Talibong Island on three different days. The mating pattern was categorized by five stages: (1) following: the male followed the female, (2) approaching and stimulating: the male approached and muzzled the female, (3) pairing: both male and female swam in parallel, ventral to ventral or dorsal to dorsal side, (4) mounting: the male copulated with the female, and (5) separating: the male and female swam in different directions. Parental care of calves included one observation of a cow embracing her neonatal calf by the flippers.     

Long‐Range Movement of Humpback Whales and Their Overlap with Anthropogenic Activity in the South Atlantic Ocean

Humpback whales (Megaptera novaeangliae) are managed by the International Whaling Commission as 7 primary populations that breed in the tropics and migrate to 6 feeding areas around the Antarctic. There is little information on individual movements within breeding areas or migratory connections to feeding grounds. We sought to better understand humpback whale habitat use and movements at breeding areas off West Africa, and during the annual migration to Antarctic feeding areas. We also assessed potential overlap between whale habitat and anthropogenic activities. We used Argos satellite‐monitored radio tags to collect data on 13 animals off Gabon, a primary humpback whale breeding area. We quantified habitat use for 3 cohorts of whales and used a state‐space model to determine transitions in the movement behavior of individuals. We developed a spatial metric of overlap between whale habitat and models of cumulative human activities, including oil platforms, toxicants, and shipping. We detected strong heterogeneity in movement behavior over time that is consistent with previous genetic evidence of multiple populations in the region. Breeding areas for humpback whales in the eastern Atlantic were extensive and extended north of Gabon late in the breeding season. We also observed, for the first time, direct migration between West Africa and sub‐Antarctic feeding areas. Potential overlap of whale habitat with human activities was the highest in exclusive economic zones close to shore, particularly in areas used by both individual whales and the hydrocarbon industry. Whales potentially overlapped with different activities during each stage of their migration, which makes it difficult to implement mitigation measures over their entire range. Our results and existing population‐level data may inform delimitation of populations and actions to mitigate potential threats to whales as part of local, regional, and international management of highly migratory marine species. Cuantificación de los Movimientos de Gran Amplitud y el Traslape Potencial con Actividad Antropogénica y las Ballenas Jorobadas en el Océano Atlántico Sur     

A floating mid-water coral nursery as larval dispersion hub: testing an idea

The global decline in reef health has prompted the need for effective management methodologies, including the development of active restoration measures. One such approach is the ‘gardening concept’ that involves use of underwater nurseries where coral fragments are farmed before their transplantation into denuded reefs. Here we document enhanced sexual reproduction in colonies of the coral Stylophora pistillata cultured in mid-water floating nursery situated in nutrient enriched water, near the fish farms in Eilat, Red Sea. We found that after 2 years of nursery, the average number of oocytes per polyp in farmed colonies was ca. 35% higher than in corresponding naturally growing colonies. Small branches in the nursery developed gravid colonies that released equal (or more) numbers of planula larvae as compared to similar size, 5-year old naturally growing colonies. These nursery-borne planulae possessed more zooxanthellae and contained more chlorophyll per larva. While settled and metamorphosed in equal rates compared to planulae originated from reef-grown colonies, the nursery borne planulae developed faster growing young colonies. We estimate that a coral nursery could generate, during the reproductive season, tens of millions of planula larvae and therefore should be regarded as a ‘larval dispersion hub’ that can be used as a management tool for natural recruitment enhancement.     

Estimating abundance of killer whales in the nearshore waters of the Gulf of Alaska and Aleutian Islands using line-transect sampling

Killer whale (Orcinus orca Linnaeus, 1758) abundance in the North Pacific is known only for a few populations for which extensive longitudinal data are available, with little quantitative data from more remote regions. Line-transect ship surveys were conducted in July and August of 2001–2003 in coastal waters of the western Gulf of Alaska and the Aleutian Islands. Conventional and Multiple Covariate Distance Sampling methods were used to estimate the abundance of different killer whale ecotypes, which were distinguished based upon morphological and genetic data. Abundance was calculated separately for two data sets that differed in the method by which killer whale group size data were obtained. Initial group size (IGS) data corresponded to estimates of group size at the time of first sighting, and post-encounter group size (PEGS) corresponded to estimates made after closely approaching sighted groups. ‘Resident’-type (fish-eating) killer whales were more abundant than the ‘transient’-type (mammal-eating). Abundance estimates of resident killer whales (991 [95% CI = 379–2,585] [IGS] and 1,587 [95% CI = 608–4,140] [PEGS]), were at least four times greater than those of the transient killer whales (200 [95% CI = 81–488] [IGS] and 251 [95% CI = 97–644] whales [PEGS]). The IGS estimate of abundance is preferred for resident killer whales because the estimate based on PEGS data may show an upward bias. The PEGS estimate of abundance is likely more accurate for transients. Residents were most abundant near Kodiak Island in the northern Gulf of Alaska, around Umnak and Unalaska Islands in the eastern Aleutians, and in Seguam Pass in the central Aleutians. This ecotype was not observed between 156 and 164°W, south of the Alaska Peninsula. In contrast, transient killer whale sightings were found at higher densities south of the Alaska Peninsula between the Shumagin Islands and the eastern Aleutians. Only two sightings of ‘offshore’-type killer whales were recorded during the surveys, one northeast of Unalaska Island and the other south of Kodiak Island. These are the first estimates of abundance of killer whale ecotypes in the Aleutian Islands and Alaska Peninsula area and provide a baseline for quantifying the role of these top predators in their ecosystem. Electronic Supplementary Material  Supplementary material is available in the online version of this article at and is accessible for authorized users.

---

The distribution and habitat preference of coastally occurring minke whales (Balaenoptera acutorostrata) in the outer southern Moray Firth, northeast Scotland

The coastal waters of the Moray Firth in northeast Scotland (57o41’N 2o40’W) provide rich, inshore feeding grounds for minke whales (Balaenoptera acutorostrata) during the summer and autumnal months. In order to better understand the habitat selection, movements and feeding ecology of the animals utilising this North Sea region, distribution data from the southern coastline of the outer Moray Firth were subsequently examined with respect to the marine physiography of the area, specifically the environmental variables water depth, slope, aspect and sediment-type. A total of 305 minke whale encounters – collected from dedicated boat surveys conducted between May and October 2001 to 2006 inclusive – were used in the construction of a Geographic Information System (GIS) for the 860 square-km study site. The subsequent analysis revealed a strong spatial preference by whales in this location for water depths between 20 and 50 metres (mean 46.9 m, SD = 30.9), steep slopes (mean 75.7 degrees, SD = 8.9), a northerly-facing aspect and sandy-gravel sediment type. Kruskal-Wallis tests for variance confirmed that the distribution of B. acutorostrata was significantly different across each of these physiographic features examined (P < 0.05). In particular, water depth and sediment type were shown to be highly correlated with the frequency of whales observed (Spearman’s Rank Correlation P < 0.05 for depth and sediment respectively). From these results, we conclude that sea bottom characteristics may be used to predict the fine-scale distribution of minke whales on their feeding grounds; the physiographic features identified providing valuable proxies for inferring prey distributions in the absence of fisheries data. However, an appreciation of both abiotic and biotic factors (using a combination of GIS and remote sensing outputs) is clearly desirable for ecosystem-based management approaches for the coastal conservation of these whales. The application of GIS capacities to ecological studies based largely on field data of these marine mammals is highly recommended in the present study to cetologists, environmental modellers and conservation managers alike.     

Sounds of two entrapped humpback whales (Megaptera novaeangliae) in Newfoundland

A wide variety of sounds were recorded from two entrapped humpback whales (Megaptera novaeangliae), a female and a male, in Newfoundland, Canada, during the summers of 1975 and 1976. The sounds included pulsed moans, moans, yups, cries, chirps and clicks. Comparisons are made between the sounds of the two whales (male and female). The most frequently produced sounds, pulsed moans and moans, are compared with similar sounds that compose part of the winter song. The sounds from the New-foundland whales were not put together into songs.     

Group-specific dialects and geographical variation in coda repertoire in South Pacific sperm whales

Codas, which are patterned series of clicks, were recorded from female and immature sperm whales (Physeter macrocephalus) in a number of locations around the South Pacific Ocean and in the Caribbean Sea. Using K-means cluster analysis, 3,644 codas were categorized based on the number of clicks and their patterning. There were 30 resulting types of coda. The numbers of codas of the different types recorded were used to construct repertoires for each recording session, day, group of whales, place, area, and ocean. Strong group-specific dialects, which seem to persist over periods of years, were apparent, overlaid on weaker geographical variation. Significant differences in repertoire were found between the Caribbean and the Pacific Ocean. Sperm whales now join killer whales (Orcinus orca) as the only cetacean species in which dialects (differences in vocal repertoire among neighboring, potentially interacting groups) have been found. Received: 13 June 1996 / Accepted after revision: 19 January 1997     

Sperm storage and mating in the deep-sea squid Taningia danae Joubin, 1931 (Oegopsida: Octopoteuthidae)

Spermatangium implantation is reported in the large oceanic squid Taningia danae, based on ten mated females from the stomachs of sperm whales. Implanted spermatangia were located in the mantle, head and neck (on both sides) or above the nuchal cartilage, under the neck collar and were often associated with incisions. These cuts ranged from 30 to 65 mm in length and were probably made by males, using the beak or arm hooks. This is the first time wounds facilitating spermatangium storage have been observed in the internal muscle layers (rather than external, as observed in some other species of squid). The implications of these observations for the mating behavior of the rarely encountered squid T. danae are discussed.     

Seasonal breeding aggregations in low-density populations of the bathyal echinoid Stylocidaris lineata

Reproduction of bathyal cidaroid sea urchins was studied between 1985 and 1991 with the aid of a manned submersible in the northern Bahamas. During May 1988 and February 1990, discrete, single-species aggregations of Stylocidaris lineata containing 2 to 6 individuals were observed between 510 and 640 m depths. Reproductive conditions of isolated and aggregated individuals were determined histologically. In February, all individuals, regardless of their spatial distribution, contained developing gametes. During the May spawning season, most isolated individuals contained spent gonads with only relict gametes, whereas individuals in discrete aggregations mostly contained ripe gonads with mature or nearly-mature gametes. Aggregations were not observed during the autumn months, when gonads were spent or immature. These data suggest that bathyal cidaroids aggregate for reproduction. An in situ survey during May indicated that pairs of S. lineata are more common than larger clumps, but no more so than predicted by chance. Homosexual and heterosexual pairs occur at the relative frequencies predicted on the basis of sex ratio. We evaluated the need for reproductive aggregation by applying Denny's (1988) model that predicts downstream sperm concentration in a turbulent boundary layer. Flow parameters were measured with dye injected from the submersible, sperm-release rate was estimated in the laboratory, and the relationship between fertilization success and sperm concentration was determined in a laboratory dilution-experiment. The model predicted that, on smooth sandy bottoms at bathyal depths, sperm concentration should remain high enough to fertilize at least some eggs several meters directly downstream from a spawning male. Aggregation may facilitate spawning synchrony, increase gamete encounter probabilities, or cause gametes to be retained at high concentrations near the adults long enough for fertilization to occur.     

Distribution and diversity of mtDNA lineages among southern right whales (Eubalaena australis) from Australia and New Zealand

Using a biopsy dart system, samples of skin tissue were collected from southern right whales (Eubalaena australis) in 1995 on two wintering grounds, southwest Australia (n = 20) and the Auckland Islands of New Zealand (n = 20); and on offshore feeding grounds at Latitudes 40 to 43°, south of Western Australia (n = 5). A variable section of the mitochondrial DNA control-region (289 nucleotides) was amplified and sequenced from these 45 individuals (21 males, 20 females and 4 of unknown sex), distinguishing a total of seven unique sequences (i.e. mtDNA haplotypes). Two haplotypes were found on both wintering grounds (including a common type representing 45% of each sample), and five types were unique to only one wintering ground. An analysis of variance adapted for molecular information revealed significant genetic differentiation between the two wintering grounds (p = 0.017). The feeding-ground sample was too small for statistical comparison with the wintering grounds, but included two haplotypes found only in the Auckland Islands as well as the common haplotype found on both wintering grounds. The nucleotide diversity and differentiation of mtDNA among the right whales was similar to that among humpback whales (Megaptera novaeangliae) from the same regions (Baker et al. 1998), but haplotype diversity was significantly reduced, perhaps as a result of more intensive hunting during the last century and continued illegal hunting during this century. Received: 16 March 1998 / Accepted: 18 December 1998     

Spawning and development of three coral-associated Lithophaga species in the Red Sea

Lithophaga date mussels from three species (L. lessepsiana, L. simplex and L. purpurea) were removed from their stony coral hosts in the Red sea at Eilat, Israel. Spawning, observed in the laboratory on several occasions during 1987–1988, appeared to be closely tied to lunar periods, occurring primarily during the last quarter and the new moon. Embryonic and larval development was typical of that described for other mytilids and, except for pigmentation differences, which could be discerned during embryogenesis, the developmental stages of the three species were indistinguishable. Development to the pediveliger stage took 3 to 4 wk in standard culture conditions, but raising the temperature to 27.5 °C increased the growth rate of larvae of L. lessepsiana by as much as three-fold, so that the pediveliger stage was attained in 16 d. Larvae resulting from spawning by L. simplex adults removed from the coral Astreopora myriophthalma grew significantly faster in culture than larvac from adults removed from the coral Goniastrea pectinata (comparison of slopes, p<0.05). The latter individuals showed a 6-d growth plateau at the early umbone stage. Metamorphically competent larvae were capable of delaying metamorphosis for up to 4mo, which would allow an extended period for dispersion and would increase the chance of finding a suitable substratum in the natural environment.     

Acoustically detected year-round presence of right whales in an urbanized migration corridor

Species' conservation relies on understanding their seasonal habitats and migration routes. North Atlantic right whales (Eubalaena glacialis), listed as endangered under the U.S. Endangered Species Act, migrate from the southeastern U.S. coast to Cape Cod Bay, Massachusetts, a federally designated critical habitat, from February through May to feed. The whales then continue north across the Gulf of Maine to northern waters (e.g., Bay of Fundy). To enter Cape Cod Bay, right whales must traverse an area of dense shipping and fishing activity in Massachusetts Bay, where there are no mandatory regulations for the protection of right whales or management of their habitat. We used passive acoustic recordings of right whales collected in Massachusetts Bay from May 2007 through October 2010 to determine the annual spatial and temporal distribution of the whales and their calling activity. We detected right whales in the bay throughout the year, in contrast to results from visual surveys. Right whales were detected on at least 24% of days in each month, with the exception of June 2007, in which there were no detections. Averaged over all years, right whale calls were most abundant from February through May. During this period, calls were most frequent between 17:00 and 20:00 local time; no diel pattern was apparent in other months. The spatial distribution of the approximate locations of calling whales suggests they may use Massachusetts Bay as a conduit to Cape Cod Bay in the spring and as they move between the Gulf of Maine and waters to the south in September through December. Although it is unclear how dependent right whales are on the bay, the discovery of their widespread presence in Massachusetts Bay throughout the year suggests this region may need to be managed to reduce the probability of collisions with ships and entanglement in fishing gear.