Site Fidelity of southern right (Eubalaena australis) and humpback whales (Megaptera novaeangliae) in Algoa Bay, South Africa

The site fidelity of humpback and southern right whales in Algoa Bay was investigated as a baseline study to examine the importance of this area for the future conservation of these species. An absence of whales since the 1980’s from Algoa Bay and more frequent sightings of southern right and humpback whales during a survey conducted between 2008 and 2011 in Algoa Bay led to the present photo-identification study. Data were collected from boat-based surveys along the coastline in 2015 and 2016 and data from a previous boat-based study during 2008-2011 assessing the occurrence of all cetaceans in Algoa Bay were added. A cumulative number of 96 individual southern right whales and 184 individual humpback whales were identified from callosity patterns and dorsal fins, respectively, over this period in Algoa Bay. A low resighting rate for both species was observed within (6.25 for southern right whales & 6.98% for humpback whales) and between years (1.04% for southern right whales & 9.24% for humpback whales) with mainly individual adult humpback whales being resighted. In contrast, all southern right whale resightings were confirmed to be mother-calf pair individuals. The timing of monthly sightings and resightings of mother-calf pair individuals in the bay may suggest that this area may serve as a fairly new nursery area for southern right whales and as a possible migratory corridor for humpback whales during their migrations to and from their breeding grounds. The sighting distribution within the bay suggest that mother-calf pairs are located closer inshore and further away from the shipping activities on the eastern side of the bay in the proximity of two operational ports. This forms an important baseline for future monitoring to assess the effect of increased shipping activity in the bay on the breeding behaviour of the whales. The site fidelity of humpback and southern right whales in Algoa Bay was investigated as a baseline study to examine the importance of this area for the future conservation of these species. An absence of whales since the 1980’s from Algoa Bay and more frequent sightings of southern right and humpback whales during a survey conducted between 2008 and 2011 in Algoa Bay led to the present photo-identification study. Data were collected from boat-based surveys along the coastline in 2015 and 2016 and data from a previous boat-based study during 2008-2011 assessing the occurrence of all cetaceans in Algoa Bay were added. A cumulative number of 96 individual southern right whales and 184 individual humpback whales were identified from callosity patterns and dorsal fins, respectively, over this period in Algoa Bay. A low resighting rate for both species was observed within (6.25 for southern right whales & 6.98% for humpback whales) and between years (1.04% for southern right whales & 9.24% for humpback whales) with mainly individual adult humpback whales being resighted. In contrast, all southern right whale resightings were confirmed to be mother-calf pair individuals. The timing of monthly sightings and resightings of mother-calf pair individuals in the bay may suggest that this area may serve as a fairly new nursery area for southern right whales and as a possible migratory corridor for humpback whales during their migrations to and from their breeding grounds. The sighting distribution within the bay suggest that mother-calf pairs are located closer inshore and further away from the shipping activities on the eastern side of the bay in the proximity of two operational ports. This forms an important baseline for future monitoring to assess the effect of increased shipping activity in the bay on the breeding behaviour of the whales

Cancer stem cells revisited

The cancer stem cell (CSC) concept was proposed four decades ago, and states that tumor growth, analogous to the renewal of healthy tissues, is fueled by small numbers of dedicated stem cells. It has gradually become clear that many tumors harbor CSCs in dedicated niches, and yet their identification and eradication has not been as obvious as was initially hoped. Recently developed lineage-tracing and cell-ablation strategies have provided insights into CSC plasticity, quiescence, renewal, and therapeutic response. Here we discuss new developments in the CSC field in relationship to changing insights into how normal stem cells maintain healthy tissues. Expectations in the field have become more realistic, and now, the first successes of therapies based on the CSC concept are emerging