An albino Cape cormorant Phalacrocorax capensis

Albinism has been recorded in many vertebrate taxa (Halls 2004). It is a genetic anomaly in which an autosomal recessive gene causes an absence of the enzyme tyrosinase, resulting in a total lack of melanin pigment in the skin, scales, hairs, feathers and eyes (van Grouw 2006). The skin and eye colour of albinos is pink because the blood can be seen through the transparent, unpigmented tissues. In birds, it is the most frequently reported colour aberration, although it is the least frequent in occurrence. This is because it is commonly mistaken for the most frequently inheritable aberration in birds, leucism, which is a partial or total lack of melanin in the plumage (sometimes also in the skin)—but not in the eye—due to an inherited disorder of the deposition of these pigments (van Grouw 2006). There are at least 10 other types of inheritable colour aberrations in birds.We thank M. Nowers for contacting the Dyer Island Conservation Trust (DICT) in regard to the sighting, H. Adams for transporting the bird to the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) rehabilitation facility, N. Parsons for performing the autopsy and D. Hamerton for granting access to the collections of the Iziko South African Museum of Cape Town.http://www.marineornithology.org/am2013ab201

Occurrence of vagrant leopard seals, Hydrurga leptonyx, along the South African coast

Leopard seals inhabit the pack-ice rim of Antarctica, and they regularly haul out on Antarctic and Subantarctic islands. Occasionally, vagrants are sighted further north in South America, Australia, New Zealand, and very rarely in southern Africa and Oceania. Here we report on an observation made on the 15th of July 2010 of a single 3-m-long juvenile leopard seal at ‘Die Dam’in theWestern Cape, South Africa (34°45.772’S, 19°42.582’E). We searched historical records and found details of four observations of leopard seals along the coast of South Africa since 1946. All of these sightings were of juvenile animals. The relative scarcity of observations is a likely reflection of the great distance from Antarctica and the Subantarctic to South Africa.http://www.sawma.co.za/am2013ab201

Population changes in a whale breeding ground revealed by citizen science noninvasive genetics

Historical exploitation, and a combination of current anthropogenic impacts, such as climate change and habitat degradation, impact the population dynamics of marine mammalian megafauna. Right whales (Eubalaena spp.) are large cetaceans recovering from hunting, whose reproductive and population growth rate appear to be impacted by climate change. We apply noninvasive genetic methods to monitor southern right whale (E. australis, SRW) and test the application of noninvasive genetics to minimise the observer effects on the population. Our aim is to describe population structure, and interdecadal and interannual changes to assess species status in the Great Acceleration period of Anthropocene. As a basis for population genetic analyses, we collected samples from sloughed skin during post-migration epidermal moult. Considering the exploration-exploitation dilemma, we collaborated with whale watching companies, as part of a citizen science approach and to reduce ad hoc logistic operations and biopsy equipment. We used mitochondrial and microsatellite data and population genetic tools. We report for the first time the genetic composition and differentiation of the Namibian portion of the range. Population genetic parameters suggest that South Africa hosts the largest population. This corresponds with higher estimates of current gene flow from Africa compared to older samples. We have observed considerable interannual variation in population density at the breeding ground and an interdecadal shift in genetic variability, evidenced by an increase in the point estimate inbreeding. Clustering analyses confirmed differentiation between the Atlantic and Indo-Pacific, presumably originating during the ice ages. We show that population monitoring of large whales, essential for their conservation management, is feasible using noninvasive sampling within non-scientific platforms. Observed patterns are concurrent to changes of movement ecology and decline in reproductive success of the South African population, probably reflecting a large-scale restructuring of pelagic marine food webs.Charles University Grant Agency, Czech Republic.https://www.elsevier.com/locate/geccoam2023Mammal Research InstituteZoology and Entomolog

Indian Ocean humpback dolphin (Sousa plumbea) movement patterns along the South African coast

1. The Indian Ocean humpback dolphin was recently uplisted to ‘Endangered’ in the recent South African National Red List assessment. Abundance estimates are available from a number of localized study sites, but knowledge of movement patterns and population linkage between these sites is poor. A national research collaboration, the SouSA project, was established in 2016 to address this key knowledge gap. Twenty identification catalogues collected between 2000 and 2016 in 13 different locations were collated and compared. 2. Photographs of 526 humpback dolphins (all catalogues and photos) were reduced to 337 individuals from 12 locations after data selection. Of these, 90 matches were found for 61 individuals over multiple sites, resulting in 247 uniquely, well‐marked humpback dolphins identified in South Africa. 3. Movements were observed along most of the coastline studied. Ranging distances had a median value of 120 km and varied from 30 km up to 500 km. Long‐term site fidelity was also evident in the data. Dolphins ranging along the south coast of South Africa seem to form one single population at the western end of the species' global range. 4. Current available photo‐identification data suggested national abundance may be well below previous estimates of 1000 individuals, with numbers possibly closer to 500. Bearing in mind the poor conservation status of the species in the country, the development of a national Biodiversity Management Plan aimed at ensuring the long‐term survival of the species in South Africa is strongly recommended. At the same time, increased research efforts are essential, particularly to allow for an in‐depth assessment of population numbers and drivers of changes therein. 5. The present study clearly indicates the importance of scientific collaboration when investigating highly mobile and endangered species.This collaborative research project was funded by the South African Network for Coastal and Oceanic Research (SANCOR), the National Research Foundation (NRF), and the University of Pretoria.http://wileyonlinelibrary.com/journal/aqc2019-02-01hj2018Mammal Research Institut

Core habitat use of an apex predator in a complex marine landscape

Manual acoustic telemetry was used to describe core habitat use of white sharks in the complex marine landscape of the Dyer Island and Geyser Rock system near Gansbaai, South Africa. We compared home range estimates and swimming pattern analyses to those established at Mossel Bay, another white shark aggregation area roughly 300 km to the east. Traditional home range estimates used in Mossel Bay did not account for movement or barriers, and were thus biased towards areas with very little shark movement (i.e. potential resting areas). We found that adapting a Movement-based Kernel Density Estimate (MKDE) could account for movement and barriers, resolving these issues. At Dyer Island and Geyser Rock, daytime shark habitat use was adjacent to the seal colony, with low rates of movement, non-linear swimming patterns and small activity areas. At night, rates of movement and linearity increased as sharks travelled further from the islands into deeper waters. MKDEs revealed 4 focal areas of habitat use: a channel between the 2 islands, an area to the south of the seal colony, another area near a kelp feature to the southwest of the seal colony and a reef system to the northwest. These results differed significantly from the habitat use at Mossel Bay, where focal areas occurred adjacent to the seal colony during the hours of dawn and dusk. We discuss possible explanations for these differences. This study is the first to make use of MKDEs in a complex marine landscape and highlights important differences in habitat use of a threatened species between 2 separate aggregation areas.Dyer Island Conservation Trust, Marine Dynamics Shark Tours and Dyer Island Cruises, VW South Africa and the National Lotteryhttp://www.int-res.comhb201