Comparison of Three Individual Identification Algorithms for Sperm Whales (Physeter macrocephalus) after Automated Detection

Photo-identification of individual sperm whales (Physeter macrocephalus) is the primary technique for mark-recapture-based population analyses for the species The visual appearance of the fluke - with its distinct nicks and notches - often serves as the primary visual differentiator, allowing humans to make recorded sightings of specific individuals. However, the advent of digital photography and the significant increase in volume of images from multiple projects in combination with pre-existing historical catalogs has made applying the method more challenging.with the required human labor for de-duplication (reduction of Type II errors) and reconciliation of sightings between large datasets too cost- and time- prohibitive. To address this, we trained and evaluated the accuracy of PIE v2 (a triplet loss network) along with two existing fluke trailing edge-matching algorithms, CurvRank v2 and Dynamic Time Warping (DTW), as a mean to speed comparison among a high volume of photographs. Analyzed data were collected from a curated catalog of well-known sperm whales sighted across years (2005-2018) off the island of Dominica. The newly-trained PIE model outperformed the older CurvRank and DTW algorithms, and PIE provided the following top-k individual ID matching accuracy on a standard min-3/max-10 sighting training data set: Rank-1: 87.0%, Rank-5: 90.5%, and Rank-12: 92.5%. An essential aspect of PIE is that it can learn new individuals without network retraining, which can be immediately applied in the presence of (and for the resolution of) duplicate individuals in overlapping catalogs. Overall, our results recommend the use of PIE v2 and CurvRank v2 for ID reconciliation in combination due to their complementary performance.

Interaction between sperm whales (Physeter macrocephalus) and northern bottlenose whales (Hyperoodon ampullatus) and deep-water trawlers in the Northwest Atlantic

Interactions between various cetacean species and fisheries are geographically widespread and diverse. Foraging in association with fishing activities may increase prey encounter rates and possibly increase the quantity and the quality of the food consumed. This paper describes interactions between benthic trawlers, targeting mainly Greenland halibut, and two whale species: sperm whales and northern bottlenose whales, in the eastern Grand Banks of the northwest Atlantic. Whale behaviors were compared during four trawling-related activities: preparing/ shooting the net, towing, hauling and transiting between fishing sites. Sperm whales and bottlenose whales were more likely to be observed during hauling. We observed probable feeding behavior of both species close to the surface at the end of hauling which suggests they are taking fish escaping from the cod end of the net when it is close to the surface. It is not clear whether feeding attempts are made during other phases of the trawling cycle. Ten sperm whales were photo-identified and six of these individuals were resighted on different days. Resights of individuals indicated that sperm whales could follow trawlers through several sets over of distances up to 234 km. While some individuals were observed to move between fishing grounds others remained within one fishing area for some time. By contrast, even though twenty-three bottlenose whales were photo-identified, there were no resights of individual whales. While northern bottlenose whales have been studied quite extensively in some adjacent areas, particularly off Nova Scotia, their behaviour and distribution within the Grand Banks fishing areas has not been well described. No matches were found between northern bottlenose whales in this study and photo-identification catalogues for the Scotian Shelf or the Arctic. Whether and how northern bottlenose whales found in this area are connected to other subpopulations remains unclear.

Cetacean community off French Guiana

Although human activities are developing in French Guiana Exclusive Economic Zone (EEZ) and surrounding countries, knowledge on diversity and ecology of cetaceans in the region is scarce. This study aimed to collect new information on the cetacean species occurring year-round in the entire French Guiana EEZ by combining visual and acoustic data obtained from three boat-based campaigns conducted by local NGOs. The GEPOG campaign was conducted from July 2011 to June 2012, four days every two months; the COHABYS campaign was performed five days per month from January to May 2018; the OSL campaign consisted in four 10-day surveys conducted in June, July, September and October 2018. The visual observation effort conducted when Beaufort sea state < 5 was 1,961 km, 1,491 km and 3,243 km respectively. Acoustic records were done when Beaufort sea state < 5 during daylight and/or nighttime, depending on the survey. A total of 132 cetacean sightings were done. Five cetacean families and 15 species were identified. Delphinidae was the family most frequently sighted (91% to 100% of groups and 99% to 100% of individuals per campaign). The most frequent species in the area were identified, along with their distribution and phenology: Guiana dolphin (Sotalia guianensis) was found in the coastal area (0-20 m), the long-beaked common dolphin (Delphinus delphis) was sighted on the shelf (20-100 m), along with the bottlenose dolphin (Tursiops truncatus) and the Atlantic spotted dolphin (Stenella frontalis) that were also common on the upper slope (100-1,500 m). Finally, the spinner dolphin (Stenella longirostris), the melon-headed whale (Peponocephala electra) and the pantropical spotted dolphin (Stenella attenuata) were frequent on the slope (100-3,500 m). The results suggest these species may be found in French Guiana waters all year round and mother and calf pairs, as indicator of reproduction, were observed for all of them except the long-beaked common dolphin and the Guiana dolphin. Mother and calf pairs of humpback whales (Megaptera novaeangliae), that potentially belong to the “A” stock, were also sighted twice, as well as two groups of sperm whales (Physeter macrocephalus) with calves. Hence, these results showed that French Guiana bears a particular responsibility for the conservation of cetacean biodiversity, but a lot remains to be done to strengthen knowledge and conservation of these species in the territory.

Diversity and Conservation of Cetaceans in Pakistan

Pakistan has total coastline of about 990 km, while diversity, distribution and abundance of cetaceans are not well understood. All historic and most recent information are based on opportunistic stranding or incidental bycatch in fishing nets, which has been a big obstacle in formulating any conservation strategy for cetaceans in Pakistan. Recent initiatives were taken and conducted surveys along the entire coastline. Although, some species have been identified well, however, still, lack of detail studies on population biology and ecology of these species. Many other species are still lack of the expertise for identification or they were misidentified. So far, a total of 18 cetacean species have been recorded in Pakistan, consisting of 3 endangered species namely blue whale (Balaenoptera musculus), Arabian sea humpback whale (Megaptera novaeangliae) and Indian Ocean humpback dolphin (Sousa plumbea), 2 vulnerable such as the sperm whale (Physeter macrocephalus) and Indo-Pacific finless porpoise (Neophocaena phocoenoid) and others 13 species are listed as data deficient. Future studies should be focused to systematic investigations on stock identification, distribution, and also evaluate the anthropogenic threats to the cetaceans. As the cetaceans has unique evolutionary history among mammals and top predator in the aquatic ecosystem. The national policies and legislations should be revised to declare them as protected species. More protected areas should be established in some important areas, such as Indus delta along the Sindh coastline to sustain the integrity of habitat and long-term conservation and management of cetaceans along the entire coastal area of Pakistan.

Sperm whales in the Neolithic Mediterranean: a tooth from the sanctuary of Monte d'Accoddi (Sardinia, Italy)

The exceptional find of the tooth of a sperm whale (Physeter macrocephalus) at Monte d'Accoddi adds to the documentation on the possible presence, and exploitation by humans, of cetaceans in the prehistoric Mediterranean. The dating (3638–3378 BC) appears to make it the oldest cetacean find in Sardinia.

Identifikasi Karakterstik Molekuler Gen 16S rRNA Parsial pada Paus Sperma (Physeter macrocephalus Linnaeus, 1758)

Paus sperma (Physeter macrocephalus) merupakan salah satu mamalia laut yang dikategorikan dalam status vulnerable pada IUCN dan status Appendix I pada CITES. Identitas asli dari paus sperma secara molekuler dapat ditelusuri. Penelitian ini bertujuan untuk mengidentifikasi karakteristik molekuler paus sperma (P. macrocephalus) berdasarkan gen 16s rRNA parsial. Tiga contoh jaringan paus sperma yang dianalisis berasal dari perairan Laut Sawu, Nusa Tenggara Timur. Hasil identifikasi berdasarkan sekuen basa nukleotida gen parsial 16S rRNA menunjukkan bahwa ketiga contoh memiliki kemiripan dengan Physeter catodon sebesar 99%, dimana P. catodon merupakan sinonim dari P. macrocephalus. Pensejajaran sekuen nukleotida dengan outgroup (Balaenoptera physalus dan Balaena mysticetus) didapatkan nilai jarak genetik ketiga contoh dengan outgroup berkisar antara 0,0093–0,0726. Selain itu, didapatkan 25 nukleotida spesifik P. macrocephalus yang mampu membedakan dari spesies outgroup. Penelitian ini mampu memvalidasi spesies P. macrocephalus berdasarkan gen 16S rRNA dan dapat dijadikan sebagai marka molekuler yang kuat untuk identifikasi P. macrocephalus.

Cetacean strandings along the German North Sea coastline 1604–2017

The occurrence of 19 cetacean species along the German North Sea coastline as well as the lower reaches of the major rivers discharging into the German Bight is reviewed for the period 1604–2017 based on records of dead animals, either stranded dead or put to death. The harbour porpoise (Phocoena phocoena) is considered the most abundant and only native species in German coastal and riverine waters. Based on written sources its presence can be traced back to at least 1651, although with statistical data only available from 1990. Finds of further 18 species have been documented: white-beaked dolphin (Lagenorhynchus albirostris), bottlenose dolphin (Tursiops truncatus), Atlantic white-sided dolphin (Lagenorhynchus acutus), common dolphin (Delphinus delphis), striped dolphin (Stenella coeruleoalba), Risso's dolphin (Grampus griseus), long-finned pilot whale (Globicephala melas), killer whale (Orcinus orca), beluga whale (Delphinapterus leucas), narwhal (Monodon monoceros), Sowerby's beaked whale (Mesoplodon bidens), northern bottlenose whale (Hyperoodon ampullatus), sperm whale (Physeter macrocephalus), minke whale (Balaenoptera acutorostrata), sei whale (Balaenoptera borealis), fin whale (Balaenoptera physalus), blue whale (Balaenoptera musculus) and humpback whale (Megaptera novaeangliae). This review corrects several false species assignments earlier introduced in literature based on incorrect scientific or ambiguous German vernacular names and recovers lost records of beluga whale, northern bottlenose whale, sperm whale and fin whale.