scholarly journals Indexing seasonal abundance of humpback whales around Abrolhos Archipelago, Bahia, Brazil

2003 ◽  
Vol 2 (1) ◽  
Author(s):  
M. E. Morete ◽  
R. M. Pace, III ◽  
C. C. A. Martins ◽  
A. C. Freitas ◽  
M. H. Engel
Keyword(s):  
Seasonal Abundance ◽  
Humpback Whales

scholarly journals Long term trends in abundance of humpback whales in Hervey Bay, Australia

2020 ◽  
pp. 237-241
Author(s):  
Paul H. Forestell ◽  
Gregory D. Kaufman ◽  
Milani Chaloupka
Keyword(s):  
Intrinsic Rate ◽  
Seasonal Abundance ◽  
Humpback Whales ◽  
Population Increase ◽  
Type Model ◽  
Photo Identification ◽  
Abundance Estimates ◽  
Antarctic Waters ◽  
Long Term Trends

Seasonal abundance estimates of humpback whales resident during the austral winter in Hervey Bay, Queensland, Australia between 1987 and 2007were obtained from a capture-mark-recapture study using photo-identification images of 3,155 individual whales. Hervey Bay is a major southboundstopover site for Breeding Stock E humpback whales returning to Antarctic waters from over-wintering in the vicinity of the Great Barrier Reef.Annual survival, recapture and abundance estimates were derived using a Cormack-Jolly-Seber modelling approach and a Horwitz-Thompson typeabundance estimator. The best-fit model was a 2-ageclass Brownie-Robson type model that estimated apparent annual survival for the non-transientwinter stopover ageclass at approximately 0.945 (95% confidence interval: 0.929–0.957). Apparent annual abundance of winter stopover humpbackwhales in Hervey Bay was estimated to have increased significantly over the past 21 years at ca. 13.4% per annum (95% CI 11.6–15.2). The mostrecent Hervey Bay winter stopover population (2007) was estimated to comprise ca. 6,246 post-yearlings (95% CI 5,011–7,482). This estimatedrate of population increase is similar to estimates for other surveys along the east Australian coast but significantly higher than the intrinsic rate ofincrease (rmax) estimated recently for several recovering Southern Hemisphere humpback whale stocks based on the feeding ground sampling.

Estimates of Fuegian sprat consumption by humpback whales in the Magellan Strait feeding area as predicted by a bioenergetic model

2021 ◽  
Vol 657 ◽  
pp. 223-239
Author(s):  
J Acevedo ◽  
J Urbán
Keyword(s):  
Fishery Management ◽  
Energy Requirement ◽  
Seasonal Abundance ◽  
Humpback Whales ◽  
Bioenergetic Model ◽  
Marine Predator ◽  
Magellan Strait ◽  
Annual Population ◽  
Feeding Area ◽  
Conservation Plans

Knowing the biomass of prey consumed by a marine predator is a prerequisite for assessing the potential of the predator for competition with fisheries. Here, we estimated the biomass of Fuegian sprat Sprattus fueguensis consumed annually by a small subpopulation of humpback whales Megaptera novaeangliae in the Magellan Strait feeding area. We used a velocity-dependent bioenergetic model that integrates annual energy requirements by sex, age class, and reproductive status, proportion of Fuegian sprat in the diet, and annual population size of whales. The annual energy required in kcal per individual whale was estimated to be 18.88 × 107 for calves, 27.92 × 107 for adults, 30.71 × 107 for pregnant females, and 42.59 × 107 for lactating females. These estimates result in an energy requirement of 19.32 × 109 and 23.41 × 109 for a seasonal abundance of 78 and 96 whales, respectively. Bayesian dietary mixing models predict that Fuegian sprat represented between 27 and 33% of the diet of the whales. This implies that humpback whales remove between 2965 and 3896 t of Fuegian sprat per year during a feeding period of 120 d. However, if estimates are extended to an abundance of 204 humpback whales during the period 2004-2017, the consumption is elevated to 8167-8383 t yr-1. The estimates provided here are useful to apply as input data for consumption by humpback whales in the Fuegian sprat fishery management as well as for conservation plans of this small and vulnerable feeding subpopulation of humpback whales.

scholarly journals Humpback whales in Banderas Bay, Mexico: relative abundance and temporal patterns between 2004 and 2017

2021 ◽  
Vol 16 (1) ◽  
pp. 33-39
Author(s):  
Iyari Janethzy Espinoza Rodríguez ◽  
Astrid Frisch Jordán ◽  
Fernando Noriega Betancourt
Keyword(s):  
Relative Abundance ◽  
Management Practices ◽  
Humpback Whale ◽  
Sea Surface ◽  
Seasonal Abundance ◽  
Humpback Whales ◽  
The North ◽  
Abundance Peak ◽  
Breeding Seasons ◽  
The North Pacific

Banderas Bay, Mexico is an important breeding and transit area for the North Pacific humpback whale (Megaptera novaeangliae) population. In this paper we estimated relative abundance (RA = number of whales/hours of navigation) as a proxy to assess population temporary patterns in the area. We analyzed data from 14 breeding seasons (2004-2017), collected between December and March each winter. A total of 8,013 whales were observed in 1,394.6 navigation hours. Average seasonal RA was 5.7 whales per hour with a maximum of 7.5 (2013) and a minimum of 4.0 (2016). Sea surface temperature (SST) averaged 25.1°C and remained within the range considered optimal for humpback whale reproduction areas. SST showed no significant correlation with RA (r = 0.183). Inter-seasonal RA values suggested an increase throughout the study period, although the increase was not statistically significant (R = 0.32; R2 = 0.10; t = 1.15, p > 0.05). Intra-seasonal analyses showed that RA in December and January were significantly higher (U = 150, p < 0.05) than in February and March; this pattern was consistent throughout the seasons of study. These results represent a shift in the intra-seasonal abundance peak relative to previous studies when most whales were observed between January and February. It is important to recognize changes in population parameters of humpback whales in breeding areas to improve management practices. This study also highlights the potential of opportunistic platforms, such as whale watching tour boats, as viable sources of quality information, particularly in contexts when funding is limited.

STUDY ON DIVERSITY AND DISTRIBUTION OF ANTS (HYMENOPTERA: FORMICIDAE) IN URBAN AND PERIURBAN AREAS OF AURANGABAD CITY, MAHARASHTRA, INDIA

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
S. D. CHATE ◽  
R. J. CHAVAN
Keyword(s):  
Rainy Season ◽  
Winter Season ◽  
Seasonal Abundance ◽  
Urban Region ◽  
Ant Community ◽  
Community Variation

The present study deals with the ant community variation in and around Aurangabad city. During the study total 16 species of ants belonging to twelve genera and four subfamilies were reported in eight habitat from urban and periurban regions. Abundance of ants was more in peri-urban region as compared to urban region. Subfamily myrmicinae was more dominant as compared to other subfamilies. Seasonal abundance of ants was seen to be more in winter season and less in rainy season.

Modeling cetacean habitat use in an urban coastal area in southeastern Brazil

2020 ◽  
Vol 642 ◽  
pp. 227-240
Author(s):  
L Lodi ◽  
R Tardin ◽  
G Maricato
Keyword(s):  
Habitat Use ◽  
Protected Areas ◽  
Linear Models ◽  
Anthropogenic Activities ◽  
Buffer Zone ◽  
Humpback Whales ◽  
Southeastern Brazil ◽  
Major Influence ◽  
Cetacean Species ◽  
Few Data

Most studies of cetacean habitat use do not consider the influence of anthropogenic activities. We investigated the influence of environmental and anthropogenic variables on habitat use by humpback Megaptera novaeangliae and Bryde’s whales Balaenoptera brydei off the coast of the Brazilian city of Rio de Janeiro. Although there are 2 marine protected areas (MPAs) in this area, few data are available on cetacean habitat use or on the overlap of different cetacean species within these MPAs. Our aim was to evaluate the effectiveness of the MPAs and propose a buffer zone to better protect the biodiversity of the study area. We conducted systematic surveys and developed spatial eigenvector generalized linear models to characterize habitat use by the species in the study area. Habitat use by humpback whales was influenced only by depth, whereas for Bryde’s whales there was the additional influence of anthropogenic variables. For Bryde’s whales, which use the area for feeding, sea surface temperature and the distance to anchorages had a major influence on habitat use. We also showed that neither of the MPAs in the study area adequately protects the hotspots of either whale species. Most of the humpback whale grid cells with high sighting predictions were located within 2 km of the MPAs, while areas of high sighting prediction of Bryde’s whales were located up to 5 km from the MPAs, closer to beaches. Our findings provide important insights for the delimitation of protected areas and zoning of the MPAs.

Seasonal Abundance and Site Fidelity of Bottlenose Dolphins (Tursiops truncatus) in Mississippi Sound

2004 ◽  
Vol 30 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Carrie W. Hubard ◽  
Kathy Maze-Foley ◽  
Keith D. Mullin ◽  
William W. Schroeder
Keyword(s):  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
Seasonal Abundance ◽  
Mississippi Sound
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