Fishers and whales in Iceland

In Iceland, as in many places globally, the detrimental impacts of whale interactions with fishing gear on both fisheries and whales are not well understood and managed. This study conducted anonymous questionnaires of Icelandic fishers and interviews of capelin purse seine boat captains to gather first-hand knowledge of the issues fishers face due to whale interaction with their fishing gear. Results suggest that the humpback whale is the large whale species that is most often entangled or encircled in fishing gear and causing damage, however on occasion other large whale species are interacting with gear as well. Interactions between humpback whales and fishing gear appears to be primarily concentrated in the north/northeast and southwest of the country where there is high fishing effort and known humpback whale feeding habitat. Humpback whale interactions with gear occurred most often with capelin purse seines, which are targeting humpback whale prey, and data suggests that bycatch of whales in this fishery may be underreported. Damage and losses due to whale collisions with gear were reported to cost fishers up to 55.000.000ISK, suggesting this can be a costly issue for which mitigation measures should be explored. The use of acoustic “pingers” is one mitigation measure that has been previously tested by capelin purse-seiners and is something that captains indicated they would be interested in continuing to try. The creation of a whale entanglement/whale-gear interaction reporting system in Iceland would aid in gathering more data and quantifying how often these events are witnessed and what the consequences of these events are to both the fishers and the whales. This study provides new information about the consequences of large whale interactions with Icelandic fisheries and suggests that future collaboration with fishers can provide insight contributing to best management practices for sustainable fishing and whale conservation.

Habitat use of common dolphin (Delphinus sp.) in the Mochima National Park, Sucre, Venezuela.

In Venezuela, common dolphin (Delphinus sp.) is considered the cetacean with the highest incidence. Studies in the region indicate a possible isolated coastal population so called Venezuelan stock settled mainly in the northeast of the country. . The objective of this study is to describe the habitat use of common dolphin in the Mochima National Park (MNP), a protected area with a high and growing anthropic pressure. Seventy surveys were carried out, with predefined survey route, from September 2009 to August 2010. Each group sighted was monitored while possible to a maximum of 30min.. During this time we registered location (Latitude-longitude), behaviour, group size and composition every 5min. Additionally, environmental variables were assessed from the sight location in a nautical chart. The study area was divided into a grid (cell: 500 x 500m) and the Coefficient of Area Use (CAU) was calculated for each cell. The proportion of the total observation time where the common dolphin displayed behaviours into the areas being used was estimated. A logistic regression model was applied to identify the variables that better explained usage pattern. In 55h of observation, 111 groups were recorded. The common dolphin used the habitat differentially, showing preferences for shallow areas near to the coast. Areas of greatest intensity of use were Tigrillo inlet and the northeast of the Caracas Islands. The probability of presence of dolphins decreased with depth and distance to the coast. Common dolphin invested more time in feeding and socializing activities. Behaviours were significantly dependent of season, group size, composition, depth and distance to the coast. Finally, these data on habitat use and behaviour allow the identification of priority habitats. Throughout the year, the MNP provided areas for refuge, feeding and resting. , It is therefore imperative to promote management and conservation policies that prevent the negative impacts of the increasing tourism and fishing activities we observed in this Park.

Body condition of gray whales (Eschrichtius robustus) feeding on the Pacific Coast reflects local and basin-wide environmental drivers

A small subset of the Eastern North Pacific gray whale population does not make the full migration from wintering grounds in Mexico to feeding grounds in the Bering, Chukchi and Beaufort seas and instead feed along the Pacific Coast between northern California and northern British Columbia – this group is known as the Pacific Coast Feeding Group (PCFG). We evaluated the body condition of PCFG whales observed in northern Washington and along Vancouver Island to evaluate how body condition of gray whales changes within and between years. We found that PCFG gray whales improve body condition through the feeding season and at varying rates by year and that they have variability in their body condition at the start and end of each feeding season. The inclusion of environmental factors, particularly the Pacific Decadal Oscillation (lagged two years) and September kelp canopy cover along the Washington coast (lagged one year), drastically improved the ability of a multiple regression model to predict average whale body condition for a given year as compared to models without environmental factors included. A comparison of our findings to a previously published study on body condition of gray whales at Sakhalin Island, Russia highlight the differences of life history strategy between a group of whales with a long migration (Sakhalin whales) and those with a short migration. Whales feeding at Sakhalin Island gain body condition quicker and more predictably to a good body condition by the end of the feeding season than the whales we studied in the PCFG. Photogrammetry may be an effective method for monitoring the effects of climate change on PCFG gray whales.

Bryde’s whale (Balaenoptera edeni) new record for mainland Portugal

Brydes’s whale (Balaenoptera edeni) is a species of baleen whale known to live year-round in warm waters, although the distribution of the species in the North Atlantic Ocean is still poorly known. In this work we report the sighting of an adult individual during the summer of 2020 in the South coast of Portugal. The whale was observed 6.4 nautical miles from the shore at a depth of 50.6 metres. Initially this individual was associated with a group of bottlenose dolphins. This is the first record of this species for mainland Portugal.

Confirmation of pygmy sperm whale, Kogia breviceps from Palk Bay, India through Cytochrome Oxidase1 (COI) sequence

The identity of a stranded cetacean from the Palk Bay has been confirmed as a pygmy sperm whale (Kogia breviceps) by the partial sequencing of mitochondrial gene cytochrome oxidase subunit-I (COI). The specimen was unambiguously discriminated from the COI sequence of Kogia sima by matching exactly with the sequence of K. breviceps. Stranding events of the pygmy whales are considered to be uncommon. The sequence developed for K. breviceps is the first of its kind attempt from Indian waters.

Bering-Chukchi-Beaufort Seas bowhead whale (Balaena mysticetus) abundance estimate from the 2019 ice-based survey

An ice-based visual survey of the Bering-Chukchi-Beaufort Seas stock of bowhead whales (Balaena mysticetus) was conducted in spring 2019 near Utqiaġvik (formerly Barrow), Alaska. A Horvitz-Thompson-type estimator is used to estimate population abundance from the resulting data, correcting for detection probabilities, whale availability within visual range, and whale passage during periods of missed effort. Analytical methods mirror those used by Givens et al. (2016) for the 2011 survey as much as possible; however, unlike 2011, no simultaneous acoustic monitoring was conducted in 2019, so the availability correction factor had to be estimated from past years. The estimated abundance was 12,505 with 95% confidence interval of (7,994, 19,560) and a CV of 0.228. This estimated abundance is markedly lower than the 2011 estimate of 16,820, but the 2019 confidence interval wholly encompasses the 2011 interval. We do not interpret this finding as evidence of a decline for many reasons including: highly unusual ice conditions, an unusual migration route that was sometimes too distant from observers to detect whales, failure to conduct watch because of closed leads during the early weeks of the migration when numerous whales likely passed, an unusually short perch, and hunters’ heavy use of powered skiffs near the observation perch which likely disturbed the whales during the survey. Furthermore, bowhead health assessment information for 2019 suggests that harvested bowheads did not exhibit obvious reductions in health condition, and aerial surveys in summer 2019 indicated high calf production (Stimmelmayr et al. 2020). Despite the challenges of the 2019 survey, the estimate is adequate for use with the International Whaling Commission’s management procedure and complies with the survey requirements of the Aboriginal Whaling Scheme.

Sightings and stranding reports of Fin whales (Balaenoptera physalus) in the Levantine Sea, with recent sightings from Turkey

Fin whales (Balaenoptera physalus) are the most commonly observed mysticetes within the Mediterranean Sea, however their status remains vulnerable (VU) and their population in decline mainly due to increasing anthropogenic activities. Sightings of fin whales in the eastern Mediterranean are negligible relative to the central and western basins which eludes to the impression that the eastern Mediterranean provides a less favourable habitat for these cetaceans. This study outlines the sighting and stranding reports of fin whales in the Levantine Basin, the latest of which (an opportunistic sighting of four sub-adults off the coast of Anamur, Turkey in March, 2019) demonstrates the continued presence of this species in the eastern Mediterranean. The current report highlights the need for increased targeted survey effort and collaborative research between neighboring waters to enhance our understanding of the population status of this vulnerable species and aid in the implementation of the necessary conservation actions that are long-missing.

Calving rates, long-range movements and site fidelity of southern right whales (Eubalaena australis) in south-eastern Australia

Within New Zealand and eastern Australia, over 58,000 southern right whales were harvested by commercial whalers between 1790 and 1980, with approximately 19,000 harvested from south-eastern Australia. Local extirpation is believed to have led to a loss of cultural memory of calving areas, contributing to the limited recovery of the south-eastern Australian population. While the number of whales observed using the south-eastern Australian coastline is increasing, there has been no change over three decades in the annual abundance of cow-calf pairs at Logans Beach in Warrnambool, Victoria, the only established calving ground in the region. Knowledge of life history parameters of the south-eastern Australian population is lacking. Here, we examine sightings and photo-identification data from southern Australia to investigate calving intervals, long range movements and fidelity to the Logans Beach nursery ground. Sightings data revealed at least 93 calves were born at Logans Beach between 1980 and 2018 (an average of 2.6 per year) with a mean calving interval of 3.5 ± 1.0 years (± SE, n = 34). Comparison between photo-identification catalogues compiled for south-eastern and south-western Australian populations shows that southern right whales are wide ranging within southern Australian waters. Females can be sighted at locations as far apart as 3,800 km across seasons and there is overlap in the wintering range of the south-eastern and south-western populations, with at least 7% of whales using both regions. We also provide the first report of an Australian southern right whale female with strong site fidelity to a calving area in one region relocating long-term to a calving area in another region. This work highlights several knowledge gaps, such as; the location of feeding and conception grounds for this population as well as the degree of mixing between the two Australian populations outside their wintering areas. In addition, the proportion of female calves born at Logans Beach returning to their natal site to calve remains unclear. Our work provides the first assessment of calving rates, movement and site fidelity within the south-eastern Australian population, critical for understanding constraints to recovery and informing conservation management of southern right whales in Australia. Targeted, long-term monitoring programs across the south-eastern Australian region are needed to provide demographic information on which to base predictions of the impacts of anthropogenic threats such as noise disturbance, entanglement and vessel strike.

Measurement error model for the Norwegian common minke whale (Balaenoptera acutorostrata acutorostrata) surveys 2008-2013

A discrete measurement error model for radial distance and angle to detected objects in line transect surveys is considered. This approach directly quantifies the effect of measurement error on the estimated effective strip half-width. We apply the method to experimental data collected over the period 2008-2013 in North Atlantic both under the assumption of multiplicative and additive measurement errors. Our results indicate that the abundance estimates considering the measurement error are consistently larger than the abundance estimates without any measurement error correction.

Interchange and movements of humpback whales (Megaptera novaeangliae) between western North Pacific winter breeding grounds in northern Luzon, Philippines and Okinawa, Japan

Humpback whales wintering in the northern Philippines and Okinawa, Japan, belong to the western North Pacific subpopulation, now recognised as a distinct population segment. The numbers for this subpopulation are low hence it is being proposed to be listed as endangered. Although previous research revealed movements between breeding grounds, the relationship between these areas remain little understood. Recent survey efforts in the Philippines resulted in a total of 234 photo-identified individuals from 1999-2016 while Okinawa had 1,445 from 1991-2014. Within the seasons a total of 100 matches were found between the two breeding grounds including 38 males and 24 females while the rest were unknown. Within these matches, eight individuals were recorded moving within seasons, including two individuals moving across seasons multiple times. The two whales were both males, where one was recorded in both breeding grounds in three different seasons (2005, 2008 and 2012). The shortest duration of recorded sightings between grounds was one whale seen in the Philippines in late March 2012 and in Okinawa 13 days later. More females with calves were sighted in the Philippines than in Okinawa and this may indicate the Philippines as a preferred nursing ground.