Christopher K. Slay

Patterns of male reproductive success in a highly promiscuous whale species: the endangered North Atlantic right whale

Parentage analyses of baleen whales are rare, and although mating systems have been hypothesized for some species, little data on realized male reproductive success are available and the patterns of male reproductive success have remained elusive for most species. Here we combine over 20 years of photo‐identification data with high‐resolution genetic data for the majority of individual North Atlantic right whales to assess paternity in this endangered species. There was significant skew in male reproductive success compared to what would be expected if mating was random (P < 0.001). The difference was due to an excess of males assigned zero paternities, a deficiency of males assigned one paternity, and an excess of males assigned as fathers for multiple calves. The variance in male reproductive success was high relative to other aquatically mating marine mammals, but was low relative to mammals where the mating system is based on resource‐ and/or mate‐defence polygyny. These results are consistent with previous data suggesting that the right whale mating system represents one of the most intense examples of sperm competition in mammals, but that sperm competition on its own does not allow for the same degree of polygyny as systems where males can control access to resources and/or mates. The age distribution of assigned fathers was significantly biased towards older males (P < 0.05), with males not obtaining their first paternity until ~15 years of age, which is almost twice the average age of first fertilization in females (8 years), suggesting that mate competition is preventing younger males from reproducing. The uneven distribution of paternities results in a lower effective population size in this species that already has one of the lowest reported levels of genetic diversity, which may further inhibit reproductive success through mate incompatibility of genetically similar individuals.

Sedation at Sea of Entangled North Atlantic Right Whales (Eubalaena glacialis) to Enhance Disentanglement

Background The objective of this study was to enhance removal of fishing gear from right whales (Eubalaena glacialis) at sea that evade disentanglement boat approaches. Titrated intra muscular injections to achieve sedation were undertaken on two free swimming right whales. Methodology/Principal Findings Following initial trials with beached whales, a sedation protocol was developed for right whales. Mass was estimated from sighting and necropsy data from comparable right whales. Midazolam (0.01 to 0.025 mg/kg) was first given alone or with meperidine (0.17 to 0.25 mg/kg) either once or four times over two hours to whale #1102 by cantilevered pole syringe. In the last attempt on whale #1102 there appeared to be a mild effect in 20–30 minutes, with duration of less than 2 hours that included exhalation before the blowhole fully cleared the water. Boat avoidance, used as a measure of sedation depth, was not reduced. A second severely entangled animal in 2009, whale #3311, received midazolam (0.03 mg/kg) followed by butorphanol (0.03 mg/kg) an hour later, delivered ballistically. Two months later it was then given midazolam (0.07 mg/kg) and butorphanol (0.07 mg/kg) simultaneously. The next day both drugs at 0.1 mg/kg were given as a mixture in two darts 10 minutes apart. The first attempt on whale #3311 showed increased swimming speed and boat avoidance was observed after a further 20 minutes. The second attempt on whale #3311 showed respiration increasing mildly in frequency and decreasing in strength. The third attempt on whale #3311 gave a statistically significant increase in respiratory frequency an hour after injection, with increased swimming speed and marked reduction of boat evasion that enabled decisive cuts to entangling gear. Conclusions/Significance We conclude that butorphanol and midazolam delivered ballistically in appropriate dosages and combinations may have merit in future refractory free swimming entangled right whale cases until other entanglement solutions are developed.

Striking the right balance in right whale conservation

Despite many years of study and protection, the North Atlantic right whale (Eubalaena glacialis) remains on the brink of extinction. There is a crucial gap in our understanding of their habitat use in the migratory corridor along the eastern seaboard of the United States. Here, we characterize habitat suitability in migrating right whales in relation to depth, distance to shore, and the recently enacted ship speed regulations near major ports. We find that the range of suitable habitat exceeds previous estimates and that, as compared with the enacted 20 nautical mile buffer, the originally proposed 30 nautical mile buffer would protect more habitat for this critically endangered species.