Papers by Geneviève Desportes
Reproduction, Sep 1, 1994
Blood samples and testes were collected from long-finned pilot whales (Globicephala melas) off th... more Blood samples and testes were collected from long-finned pilot whales (Globicephala melas) off the Faroe Islands at irregular intervals over a period of 3 years (July 1986\p=n-\December 1989). Changes in testis mass (n = 674) and plasma testosterone concentrations (n = 214), measured by radioimmunoassay, were examined with respect to age, bodylength and bodymass of the animals. Corresponding to a rapid testicular growth (from 0.25 kg up to 1.9 kg), puberty occurred in male pilot whales of 4.6\p=n-\5.7m in bodylength, 1.2\p=n-\1.9tonnes in bodymass and 11\p=n-\22 years of age. Changes in plasma testosterone concentrations confirmed this result, with very low values (< 2 ng ml \m=-\ 1) in immature animals (testis mass < 0.2 kg), followed by a sharp increase (from 2 to 29 ng ml \m=-\ 1) during the pubertal period, and the maintenance of high concentrations with large variability (> 1.5 ng ml \ m=-\ 1 to 14 ng ml \ m=-\ 1) in mature males. Testosterone concentrations were significantly correlated with testis mass (P < 0.001), but not with bodylength or age, and very large individual variations were observed in mature males. The average age, length and mass at the attainment of sexual maturity were estimated at 16.99 \ m=+-\ 0.30 years, 5.162 \ m=+-\ 0.013 m and 1.403 \ m=+-\ 0.005 tonnes, respectively.
Global Ecology and Conservation
Journal of Cetacean Research and Management
NAMMCO Scientific Publications
NAMMCO Scientific Publications
The last extensive (pan-Arctic) review on knowledge available on the bearded seal (Erignathus bar... more The last extensive (pan-Arctic) review on knowledge available on the bearded seal (Erignathus barbatus) was conducted by Cameron et al. in 2010. As bearded seals are hunted off Svalbard and Greenland but no stock assessments are available, NAMMCO requested a status review, and if possible, an assessment of the species in its area. This literature review attempts to summarise the knowledge that has become available post 2010, with a focus on the Atlantic Arctic. A large amount of information has become available on the behaviour of the bearded seal, with hearing, vocalisation, haul-out behaviour and movement patterns (through satelitte tagging), and their phenology, being well studied. A database of baseline blood parameters is slowly being built but is still limited. New data on distribution has emerged from PAM studies and non-targeted surveys. Abundance estimates are missing for Svalbard, but partial estimates have become available for the North Water Polynya in 2009 and 2014. Add...
Bulletin of the Ecological Society of America 78(4 Suppl. ), Feb 26, 1997
TNASS estimates the abundance of cetacean populations in the Northern North Atlantic from survey ... more TNASS estimates the abundance of cetacean populations in the Northern North Atlantic from survey data collected during summer 2007. It will add to the long-term series of international North Atlantic Sightings Surveys (NASS) that have previously been conducted in 1987, 1989, 1995 and 2001. After the completion of TNASS in 2007, the NASS-TNASS series will have occurred over a time period of 20 years, which provides a realistic opportunity for detecting changes in abundance over time for species with long life spans and slow reproductive rates.
Journal of Zoology, 1996
ABSTRACT The northern bottlenose whale has been caught in the Faroe Islands for centuries, with w... more ABSTRACT The northern bottlenose whale has been caught in the Faroe Islands for centuries, with written catch records going back to 1584 and unbroken from 1709. A total of 811 whales has been reported in the period 1584-1993. The Faroese bottlenose whaling is an opportunistic drive fishery of pods sighted very close to shore. Natural strandings also occur. Most of the fishery has taken place in two close southern villages of the Faroese archipelago (72% of the catch). The high season is 20 August-20 September. The pod contains 1-7 whales with an average of 2.1 whales. Most of them are immature males or mature females with juveniles, but as many males as females have been caught overall. Females and males at every stage of development have been caught in the Faroes, although it appears that the bottlenose whales approaching the Faroese coast and then driven ashore have not included as large and as small individuals as those shot offshore. A body weight (W in kg) and length (L in cm) relationship has been calculated for both sexes combined: W = 0.0000131 x L3.07. Females and immature males have a grey and bulbous forehead. As the males mature their forehead becomes flatter and lighter, and only large mature males have a white and flat forehead. The stomach contents of nine whales contained in total at least 13 squid species. A comparison with pilot whaling shows that bottlenose whales arrive 2-4 weeks later than the pilot whales and that the geographical distribution of the catch is very different for both species, suggesting a different pattern of migration through the archipelago.
Aquatic Mammals
During the past 25 years, Fjord&Baelt (F&B) in Denmark has kept harbour porpoises (Phocoena phoco... more During the past 25 years, Fjord&Baelt (F&B) in Denmark has kept harbour porpoises (Phocoena phocoena) for research and education. Some animals were bycaught in static fishing gear and then brought to the center under a special permit, and some were born at the facility. At F&B, the harbour porpoises are trained several times every day for research projects, public presentations for visitors, and educational programs for schools. They are also provided with enrichment activities in addition to the enclosure's natural and dynamic habitat. The center's research on animal behaviour, reproductive and diving physiology, outreach, and bioacoustics have resulted in more than 60 scientific publications, involving scientists from research institutions in Denmark and abroad. There is a close collaboration between F&B and the adjacent Marine Biological Research Center (MRC) of the University of Southern Denmark (SDU), also established in 1997.
NAMMCO Scientific Publications, 2009
This paper uses data from 3 programmes: (1) the North Atlantic Sightings Surveys (NASS) surveys u... more This paper uses data from 3 programmes: (1) the North Atlantic Sightings Surveys (NASS) surveys undertaken throughout much of the central and eastern North Atlantic north of about 40° N in 1987, 1989, 1995 and 2001; (2) the MICA-93 programme; and (3) the north eastern Atlantic segment of the Small Cetacean Abundance in the North Sea (SCANS) survey in 1994. The data from all surveys were used to examine the distribution of common dolphins in the NE Atlantic. No sightings were made north of 57° N. An initial attempt to examine distribution against 4 potential non biological explanatory variables was made. A simple interpretation of the preliminary analyses presented here is that the primary areas for groups of common dolphins were in waters over 15° C and depths of 400-1,000 m (there does appear a link with shelf features), between around 49°-55° N especially between 20°-30°W. An illustrative example of spatial modelling is presented. Only for 1 year (and part of the total survey area...
NAMMCO Scientific Publications, 2003
The harbour porpoises kept at the Fjord & Bælt since April 1997 offer a unique opportunity to gai... more The harbour porpoises kept at the Fjord & Bælt since April 1997 offer a unique opportunity to gain a better understanding of the reproductive function in harbour porpoises, especially in terms of physiological cycle and concomitant behavioural traits. A study was initiated in 1997 with the following aims: 1) characterising the annual reproductive cycle in terms of behaviour and endocrine activity; 2) finding the most suitable techniques for a longitudinal investigation of the reproductive function, in particular with respect of the small size of the species; 3) ensuring a precise monitoring of the reproductive state of the Fjord & Bælt porpoises; 4) evaluating the best techniques for a vertical assessment of the reproductive state in wild harbour porpoises; 5) providing comparative basis for toxicological studies.Three harbour porpoises have participated in the study: a male and a female estimated 1-2 years old at their arrival at the Centre in 1997, and a one-year old female. The d...
NAMMCO Scientific Publications, 2003
Two harbour porpoises of an estimated age of 1-2 years were held in captivity from April 1997 and... more Two harbour porpoises of an estimated age of 1-2 years were held in captivity from April 1997 and were still alive in April 2002, after rescue from pound nets set in inner Danish waters. They are presently housed in an outdoor penned-off area of Kerteminde fjord. Their growth (total body length, girth, body weight and blubber thickness) and daily dietary intake (weight of fish, dietary composition and energy value) have been monitored since capture. The general activity of the animals was regularly monitored, including two 24-hour long observation periods. Initial body weights were 37.5 kg for Eigil (male) and 40.5 kg for Freja (female). Both porpoises lost 4 to 5 kg in the first few days because of their initial refusal to feed from the hand. Then body weight increased steadily reaching a peak of 44.75 kg for Eigil and 51.6 kg for Freja in early February 1998. A fluctuation in body weight with peaks of 44 to 45 kg for the male and 51to 56 kg for the female in winter followed by low...
Foods, 2021
Achieving a sustainable global food chain is becoming particularly acute as modern Western diets ... more Achieving a sustainable global food chain is becoming particularly acute as modern Western diets are adopted in a growing number of countries and cultures around the world. Understanding the consequences that this shift has on health and sustainability is important. This exploratory study is the first to apply the life cycle assessment (LCA) methodology to analyze the sustainability implication of ongoing dietary shifts in Greenland, where locally hunted seal meat is increasingly being replaced by imported livestock products, primarily pig and poultry produced in Denmark. This dietary shift, indirectly driven by international trade bans such as the EU seal product ban, has sustainability implications. To inform and support more comprehensive analyses and policy discussions, this paper explores the sustainability of these parallel Greenlandic food supply chains. A quantitative comparison of the greenhouse gas emissions of Greenlandic hunted seal and Danish pig and poultry is compleme...
To gain insight into the time allocation and diving behaviour of harbour porpoises in Danish and ... more To gain insight into the time allocation and diving behaviour of harbour porpoises in Danish and adjacent waters, satellite linked dive recorders were mounted on 14 harbour porpoises. The animals were incidentally caught alive by fishermen using pound nets during 199799 in the Danish Belt seas. Information on diving behaviour was collected from April to November. Contact with individual porpoises remained for up to 130 days. The average number of dives per hour was 29 during April-August and 43 during October-November. Daily maximum dive depth corresponds to the depth of the Belt seas and Kattegat where depth generally does not exceed 50m. Maximum dive depth recorded was 132m from animals moving north into Skagerrak. Dives were frequently recorded in the category 10-15min, but could potentially be an artefact of the sampling regime. The diurnal pattern shows that harbour porpoises dive continuously both day and night, but with peak activity during daylight hours. On average they spe...
Nammco Scientific Publications, 2020
The North Atlantic Sightings Surveys (NASS), covering a large but variable portion of the Central... more The North Atlantic Sightings Surveys (NASS), covering a large but variable portion of the Central and Eastern North Atlantic, were conducted in 1987, 1989, 1995, 2001, 2007 and 2015. Sightings of killer whales (Orcinus orca), a non-target species, were relatively rare in the Central Atlantic (Icelandic and Faroese) portions of the survey area. In cases where sighting numbers were insufficient, we pooled sightings over several surveys to derive a distance detection function and used this to estimate abundance using standard Distance Sampling methodology. Uncorrected estimates were produced for all surveys, and estimates corrected for perception bias were produced for the 2001 and 2015 surveys. Killer whales were sighted in all areas but were most common in the eastern part of the survey area. Uncorrected abundance in the NASS core area ranged from a low of 4,736 (95% CI: 1,842–12,176) in 1995 to a maximum of 15,142 (95% CI: 6,003–38,190) in 2001. The low precision of the estimates ma...
Summary of NAMMCO's recent activities in the Arctic and participation in the work of the AC.
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Papers by Geneviève Desportes