A comparison of CTD satellite-linked tags for large cetaceans - Bowhead whales as real-time autonomous sampling platforms

There is an increasing need for comprehensive oceanographic sampling, and taking advantage of marine mammal studies of movements and habitat use for augmenting spatial and temporal coverage, especially in remote and inaccessible areas, is an attractive approach. Oceanographic sampling instruments that transmit profiles of temperature and salinity (CTD) via satellite were deployed on bowhead whales Balaena mysticetus. A novel satellite-linked CTD tag (WC) was compared to an established design (SMRU). The two types of tags were deployed equally on nine bowhead whales in West Greenland. Both tag types used Argos for relaying data and locations, while the WC tag also provided Fastloc-GPS for more accurate locations. One whale carried both tag types. When comparing the two tag types deployed on the same whale, more complete data were obtained from the WC tag in terms of number of profiles, locations and transmissions received, although placement of the tag on the back of the whale and antenna position may have affected some of these parameters. Why transmissions terminated is difficult to determine, however, physical loss of the tag from the whale and mechanical damage to the antenna are the most likely; none of the tags failed because of battery exhaustion. Although, differences in performance of the two tag types were found, we conclude that both satellite-linked CTD tag types deployed on large cetaceans can provide high resolution oceanographic profiles at times and in areas where traditional methods for collecting oceanographic data are logistically difficult and prohibitively expensive.publishedVersio

Reactions of Narwhals, Monodon monoceros, to Killer Whale, Orcinus orca, Attacks in the Eastern Canadian Arctic

A Killer Whale attack on Narwhals was observed at Kakiak Point in Admiralty Inlet, Nunavut, Canada, in August 2005. Behavioral responses of both Narwhals and Killer Whales were documented by direct observation. Data collected from Narwhals instrumented with satellite-linked transmitters 5 days prior to the arrival of Killer Whales were used to examine changes in Narwhal movement patterns (e.g., dispersal and clumping) five days before the attack, during the attack, and five days after Killer Whales left the area. A minimum of four Narwhals were killed by 12-15 Killer Whales in a period of 6 hours. Narwhals showed a suite of behavioral changes in the immediate presence of Killer Whales including slow, quiet movements, travel close to the beach (<2 m from shore), use of very shallow water, and formation of tight groups at the surface. These behavioral changes are consistent with Inuit accounts of Killer Whale attacks on Narwhals. During the attack, Narwhals dispersed broadly, the groups were less clumped (standard deviation of inter-whale mean latitudes and longitudes), Narwhal space-use doubled from pre-attack home ranges of 347 km2 to 767 km2 (kernel 50% probability), and Narwhals shifted their distribution further south of the attack site. After the disappearance of Killer Whales, north-south dispersal of Narwhals contracted and was similar to pre-attack levels, total space use decreased slightly (599 km2), yet west-east dispersal remained high. Narwhals were distributed significantly (P < 0.001) more broadly offshore in areas not used before the occurrence of Killer Whales. In general, short-term reactions of Narwhals to Killer Whale presence were obvious; yet normal behavior (as observed from shore) resumed shortly after Killer Whales left the area. Long-term (five day) Narwhal behavioral responses included increased dispersal of Narwhal groups over large offshore areas. This is among the few reports of eyewitness Killer Whale attacks on Narwhals in the high Arctic and is the first time changes in Narwhal behavior have been documented in response to a predation event through the use of satellite telemetry

Identification of Potential Foraging Areas for Bowhead Whales in Baffin Bay and Adjacent Waters

The bowhead whale (Balaena mysticetus) is the Arctic’s largest and most dependent predator on zooplankton; however, knowledge about its important foraging areas in Baffin Bay and adjacent waters is limited. Data on movement, horizontal velocity (ms-1), dive depth (m), and dive rate (dives h-1) were obtained from 39 bowhead whales (31 females, 6 males, and 2 of undetermined sex) instrumented with satellite-linked time-depth recorders (SLTDRs) in spring 2009 and 2010 in Disko Bay, West Greenland. Thirty-eight whales provided information on dive rates and movement, and potential foraging areas were identified on the basis of low dive rates and stationary behaviour. Nine potential foraging areas were identified: Disko Bay and adjacent region, Clyde Inlet, Isabella Bay, Broughton Island, Cumberland Sound, Frobisher Bay, Hudson Strait, southern Foxe Basin, and northern Foxe Basin. Two females returned to Disko Bay the following spring (duration of tags > 420 days). Their diving behavior indicated that all whales exhibited a large degree of flexibility in their use of potential feeding areas in Baffin Bay and adjacent waters. The variability of habitat selection may buffer against climate-induced changes in the preferred habitats of bowhead whales.La baleine boréale (Balaena mysticetus) est le plus grand prédateur de zooplancton de l’Arctique. Elle est également le prédateur qui dépend le plus de cette espèce. Cependant, on possède peu de connaissances sur les importantes zones d’alimentation de la baleine boréale dans la baie de Baffin et les eaux adjacentes. Des données au sujet des déplacements et de la vélocité horizontale (ms-1), de la profondeur des plongeons (m) et du taux de plongeons (plongeons h-1) ont été obtenues à partir de 39 baleines boréales (31 femelles, six mâles et deux baleines au sexe non déterminé) dotées d’enregistreurs de profondeur temporelle satellitaires (SLTDR) au printemps 2009 et au printemps 2010 dans la baie de Disko, dans l’ouest du Groenland. Trente-huit baleines ont permis d’obtenir de l’information sur le taux de plongeons et les déplacements, de même que sur les zones d’alimentation potentielles en fonction des plongeons en faible profondeur et du comportement stationnaire. Neuf zones d’alimentation potentielles ont été déterminées, soit la baie de Disko et la région adjacente, le passage Clyde, la baie Isabella, la baie Broughton, le détroit de Cumberland, la baie Frobisher, le détroit d’Hudson, le sud du bassin Foxe et le nord du bassin Foxe. Deux femelles sont retournées à la baie de Disko le printemps suivant (durée des étiquettes > 420 jours). Leur comportement de plongée laissait entrevoir que toutes les baleines possédaient un grand degré de souplesse quant à leur utilisation des zones d’alimentation potentielles dans la baie de Baffin et les eaux adjacentes. La variabilité de la sélection de l’habitat peut avoir pour effet d’amortir les changements découlant du climat dans les habitats préférés des baleines boréales

Investigation and implications of spatial and temporal patterns in sex ratio data from West Greenland minke whale catches.

The sub-group based its deliberations on the computations set out below, which were carried out by Givens following input from sub-group members

Fall and Winter Movements of Bowhead Whales (Balaena mysticetus) in the Chukchi Sea and Within a Potential Petroleum Development Area

Working with subsistence whale hunters, we tagged 19 mostly immature bowhead whales (Balaena mysticetus) with satellite-linked transmitters between May 2006 and September 2008 and documented their movements in the Chukchi Sea from late August through December. From Point Barrow, Alaska, most whales moved west through the Chukchi Sea between 71˚ and 74˚ N latitude; nine whales crossed in six to nine days. Three whales returned to Point Barrow for 13 to 33 days, two after traveling 300 km west and one after traveling ~725 km west to Wrangel Island, Russia; two then crossed the Chukchi Sea again while the other was the only whale to travel south along the Alaskan side of the Chukchi Sea. Seven whales spent from one to 21 days near Wrangel Island before moving south to northern Chukotka. Whales spent an average of 59 days following the Chukotka coast southeastward. Kernel density analysis identified Point Barrow, Wrangel Island, and the northern coast of Chukotka as areas of greater use by bowhead whales that might be important for feeding. All whales traveled through a potential petroleum development area at least once. Most whales crossed the development area in less than a week; however, one whale remained there for 30 days.De concert avec les pêcheurs de baleines de subsistance, nous avons apposé des transmetteurs satellitaires sur 19 baleines boréales (Balaena mysticetus) pour la plupart immatures entre les mois de mai 2006 et septembre 2008, puis nous avons tenu compte de leurs mouvements dans la mer de Tchoukotka de la fin août jusqu'au mois de décembre. À partir de Point Barrow, en Alaska, la plupart des baleines se déplaçaient vers l'ouest dans la mer de Tchoukotka entre 71˚ et 74˚ N de latitude; neuf baleines ont fait la traversée en six à neuf jours. Trois baleines ont regagné Point Barrow pendant 13 à 33 jours, dont deux après avoir franchi 300 kilomètres en direction ouest et une après avoir franchi environ 725 kilomètres en direction ouest jusqu'à l'île Wrangel, en Russie; ensuite, deux baleines ont traversé la mer de Tchoukotka de nouveau tandis que l'autre était la seule baleine à se déplacer vers le sud le long du côté de la mer de Tchoukotka situé en Alaska. Sept baleines ont passé de un à 21 jours près de l'île Wrangel avant d'aller au sud du côté nord de Tchoukotka. Les baleines ont passé, en moyenne, 59 jours à suivre la côte de Tchoukotka vers le sud-est. L'analyse de la densité des noyaux a permis de déterminer que Point Barrow, l'île Wrangel et la côte nord de Tchoukotka sont des régions plus grandement utilisées par les baleines boréales, régions qui peuvent être importantes aux fins de l'alimentation. Toutes les baleines ont traversé une zone de mise en valeur éventuelle du pétrole au moins une fois. La plupart des baleines ont traversé la zone de mise en valeur en moins d'une semaine. Cela dit, une baleine est restée à cet endroit pendant 30 jours

Autumn movements of fin whales (Balaenoptera physalus) from Svalbard, Norway, revealed by satellite tracking

Insight into animal movements is essential for understanding habitat use by individuals as well as population processes and species life-history strategies. In this study, we instrumented 25 fin whales with ARGOS satellite-transmitters in Svalbard, Norway, to study their movement patterns and behaviour (Area Restricted Search (ARS), transiting or unknown) during boreal autumn/early winter. Ten of the whales stayed in the tagging area (most northerly location: 81.68°N) for their entire tracking periods (max 45 days). The other 15 whales moved in a south-westerly direction; the longest track ended off the coast of northern Africa (> 5000 km from the tagging location) after 96 days. The whales engaged in ARS behaviour intermittently throughout their southward migrations. During transit phases the whales moved quickly; one individual maintained an average horizontal speed of 9.3 km/h (travelling 223 km per day) for a period of a week. This study documents that: (1) some fin whales might remain at high latitudes during winter; (2) the whales that do migrate probably feed along the way; (3) they can maintain high transiting speed for long periods and; (4) one breeding area for this species is likely located in deep, warm water some 100 km west of Morocco.publishedVersio