Net Entanglements of Baleen Whales in the Inshore Fishery of Newfoundland

1979 ◽  
Vol 36 (5) ◽  
pp. 521-528 ◽  
Author(s):  
J. S. Perkins ◽  
P. C. Beamish
Keyword(s):  
Key Words ◽  
Newfoundland And Labrador ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Balaenoptera Acutorostrata ◽  
Balaenoptera Physalus ◽  
Baleen Whales ◽  
Minke Whales ◽  
Capelin Mallotus Villosus ◽  
Inshore Waters

This paper documents net entrapments of baleen whales in the inshore waters of Newfoundland and Labrador. The species involved are principally minke whales (Balaenoptera acutorostrata) and humpback whales (Megaptera novaeangliae). Finback whales (Balaenoptera physalus) are also caught in nets but far less frequently. The timing of these entrapments corresponds with the spawning season for capelin (Mallotus villosus) on the beaches around the province. The magnitude and implications of this problem, both to the whales and the fisherman, are assessed. Key words: baleen whales, net entrapments, mortality assessment, capelin, Balaenoptera acutorostrata, B. physalus, Megaptera novaeangliae

Observations on Three Species of Baleen Whales off Northern Newfoundland and Adjacent Waters

1977 ◽  
Vol 34 (9) ◽  
pp. 1436-1440 ◽  
Author(s):  
Judith Perkins ◽  
Hal Whitehead
Keyword(s):  
Key Words ◽  
Population Size ◽  
Geographical Distribution ◽  
Humpback Whales ◽  
Population Estimate ◽  
Balaenoptera Acutorostrata ◽  
Balaenoptera Physalus ◽  
Baleen Whales ◽  
Sailing Boat ◽  
Water Depths

Minke, Balaenoptera acutorostrata, finback, Balaenoptera physalus, and humpback whales, Megaptera novaeangliae, were observed off northern Newfoundland and southern Labrador between June and September 1975, principally from a sailing boat. Distributions for these species are recorded and correlated with water depths and distances from shore. Several isolated sounds, but no "songs," were recorded from humpback whales in Notre Dame Bay, where a population estimate was calculated based on a new method of photographic marking of individuals. Key words: baleen whales, geographical distribution, population size, photographic tagging

Predicting Inshore Whale Abundance — Whales and Capelin off the Newfoundland Coast

1985 ◽  
Vol 42 (5) ◽  
pp. 976-981 ◽  
Author(s):  
Hal Whitehead ◽  
J. E. Carscadden
Keyword(s):  
Fishing Gear ◽  
Balaenoptera Acutorostrata ◽  
Short Term ◽  
Balaenoptera Physalus ◽  
Baleen Whales ◽  
Large Numbers ◽  
Class Strength ◽  
Capelin Mallotus Villosus ◽  
Abiotic Variables ◽  
Northeast Coast

Inshore abundance of baleen whales along the Newfoundland coasts changed considerably during the period 1973–83. In particular, large numbers of humpbacks were present along the northeast coast each summer between 1977 and 1980. This influx led to entrapment of whales in fishing gear. Counts of humpback (Megaptera novaeangliae), finback (Balaenoptera physalus), and minke (Balaenoptera acutorostrata) whales during standard surveys along the coast are used as indices of inshore abundance, and are related to the year-class strengths of capelin (Mallotus villosus), their major food in the Newfoundland region. Whales are found inshore when there are few immature capelin offshore. Minke whale distributions seem more closely related to the abundance of 1- to 2-yr-old, immature capelin, but humpback and finback whales are found inshore with low abundances of 2- to 3-yr-old, mainly immature capelin. We suggest that estimates of capelin year-class strength predicted from abiotic variables can be used to predict inshore whale abundance, at least 1 yr in advance. The extreme influx of humpbacks of the late 1970s is unlikely to recur in the short term. The analysis suggests that finback populations in the area are declining.

Baleen whales and their prey in a coastal environment

1989 ◽  
Vol 67 (6) ◽  
pp. 1523-1530 ◽  
Author(s):  
John F. Piatt ◽  
David A. Methven ◽  
Alan E. Burger ◽  
Ruth L. McLagan ◽  
Vicki Mercer ◽  
...  
Keyword(s):  
Environmental Parameters ◽  
Abundance Ratio ◽  
Coastal Environment ◽  
Strongly Correlated ◽  
Balaenoptera Acutorostrata ◽  
Mallotus Villosus ◽  
Balaenoptera Physalus ◽  
Baleen Whales ◽  
Intermediate Depth ◽  
Capelin Mallotus Villosus

Patterns of abundance of humpback (Megaptera novaeangliae), fin (Balaenoptera physalus), and minke (Balaenoptera acutorostrata) whales are described in relation to the abundance of their primary prey, capelin (Mallotus villosus), during 1982–1985 at Witless Bay, Newfoundland. The abundance ratio of the three whale species was 10:1:3.5, respectively. Abundance of all whale species was strongly correlated with abundance of capelin through each season and between years. Capelin abundance accounted for 63% of the variation in whale numbers in 1983 and 1984, while environmental parameters (e.g., water temperatures) accounted for little variance. The amount of capelin consumed by whales was small (< 2%) compared with the amount available. All three species overlapped temporally at Witless Bay, but spatial overlap was reduced as fins occurred primarily offshore, minkes primarily inshore, and humpbacks in bay habitats of intermediate depth.

Corneal anatomy of marine mammals

1993 ◽  
Vol 71 (11) ◽  
pp. 2282-2290 ◽  
Author(s):  
M. T. Pardue ◽  
J. G. Sivak ◽  
K. M. Kovacs
Keyword(s):  
Marine Mammals ◽  
Equatorial Region ◽  
Balaenoptera Acutorostrata ◽  
Marine Habitat ◽  
Corneal Surface ◽  
Balaenoptera Physalus ◽  
Phoca Groenlandica ◽  
Minke Whales ◽  
Transmission Electron ◽  
Ultrathin Sections

The corneal anatomy of fin whales (Balaenoptera physalus), minke whales (Balaenoptera acutorostrata), harp seals (Phoca groenlandica), ringed seals (Phoca hispida), and bearded seals (Eriganthus barbatus) was examined to determine if marine mammals have evolved specialized corneas for life in a marine habitat. One to seven eyes of each species were analyzed: paraffin sections stained with haematoxylin and eosin for light microscopy; and ultrathin sections for transmission electron microscopy. All corneas contain the five typical mammalian layers: epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. The corneas of these marine mammals are thicker than human corneas because of a thicker stromal layer. The other layers are thinner than those found in humans, except for the epithelial layer in the bearded seal and the cetaceans where it may provide extra protection for the eye during feeding behaviour. The epithelial cells in all corneas studied have an abundance of tonofilaments, which may strengthen the cells and distribute force across the corneal surface. No special organization of collagen fibrils was found in the stroma that would offer protection from ultraviolet radiation or glare for pinnipeds when on ice. The thickness of the sclera in the cetaceans may serve to hold the inner globe of the eye in an elliptical shape, while the thinning of the sclera in the equatorial region in pinnipeds may flatten the eye in air to reduce aerial myopia.

Exclusive adjoining ranges in individually identified minke whales (Balaenoptera acutorostrata) in Washington state

1983 ◽  
Vol 61 (1) ◽  
pp. 174-181 ◽  
Author(s):  
Eleanor M. Dorsey
Keyword(s):  
Washington State ◽  
Small Scale ◽  
Territorial Defense ◽  
Balaenoptera Acutorostrata ◽  
Marine Waters ◽  
Baleen Whales ◽  
Distinctive Features ◽  
Naturally Occurring ◽  
Minke Whales ◽  
Free Ranging

Free-ranging minke whales in the inland marine waters of Washington, U.S.A., were found to be individually identifiable from photographs of naturally occurring distinctive features. Sixteen individuals were recognized and observed from small boats 66 times over 3.5 months in 1980, and four of these whales were also recognized from photographs taken in 1977 and 1978. Three exclusive adjoining ranges were found in about 600 km2, each one shared by up to at least seven minke whales, with only two instances of crossover between areas in 70 sightings. Feeding was observed in all three areas, and the whales within each area appeared most of the time to be acting independently of one another. No calves were seen, and no overt acts of territorial defense were observed. This is the first known report in baleen whales of nonoverlapping ranges on a very small scale.

Interspecific cetacean interactions during the breeding season of humpback whale (Megaptera novaeangliae) on the north coast of Bahia State, Brazil

2009 ◽  
Vol 89 (5) ◽  
pp. 961-966 ◽  
Author(s):  
Marcos R. Rossi-Santos ◽  
Elitieri Santos-Neto ◽  
Clarêncio G. Baracho
Keyword(s):  
Breeding Season ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
North Coast ◽  
Balaenoptera Acutorostrata ◽  
Cetacean Species ◽  
The North ◽  
Eastern Brazil ◽  
North Eastern ◽  
Stenella Attenuata

The large majority of cetacean interspecific studies report only on dolphin interactions, while studies on interactions between odontocete and mysticete are less common. The present work aims to report on sightings of cetacean interactions, during the breeding season of humpback whales(Megaptera novaeangliae), along 370 km of the Bahia State, north-eastern Brazil, addressing aspects of cetacean distribution and behaviour. During 7 seasons (2000–2006), a total of 230 research cruises were performed, in which 38 events of interactions among humpback whales and other cetaceans(Tursiops truncatus, Steno bredanensis, Peponocephala electraandBalaenoptera acutorostrata)were observed, plus another 5 encounters without the whale's presence, includingT. truncatus, S. bredanensis, P. electra, Stenella clymeneandStenella attenuata. Our results confirm the occurrence of multiple cetacean species in the Bahia State, being the first study in the world to report on a large range of interactions involving another 4 cetacean species, grouped with up to 3 mixed species per sighting, with humpback whales in their annual breeding ground.

scholarly journals Social survival: humpback whales (Megaptera novaeangliae) use social structure to partition ecological niches within proposed critical habitat

2020 ◽  
Author(s):  
Janie Wray ◽  
Eric Keen ◽  
Éadin N. O’Mahony
Keyword(s):  
Habitat Use ◽  
Social Structure ◽  
Niche Partitioning ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Baleen Whales ◽  
Fjord System ◽  
The Social ◽  
Social Niche

ABSTRACTAnimal culture and social bonds are relevant to wildlife conservation because they influence patterns of geography, behavior, and strategies of survival. Numerous examples of socially-driven habitat partitioning and ecological-niche specialization can be found among vertebrates, including toothed whales. But such social-ecological dynamics, described here as ‘social niche partitioning’, are not known among baleen whales, whose societies -- particularly on foraging grounds -- are largely perceived as unstructured and incidental to matters of habitat use and conservation. However, through 16 years of behavioral and photo-identification observations of humpback whales (Megaptera novaeangliae) feeding within a fjord system in British Columbia, Canada, we have documented long-term pair bonds (lasting up to 12 years) as well as a complex societal structure, which corresponds closely to persistent patterns in feeding strategy, long-term site fidelity (extended seasonal occupancy and annual rate of return up to 75%), specific geographic preferences within the fjord system, and other forms of habitat use. Randomization tests of network congruency and clustering algorithms were used to test for overlap in patterns of social structure and habitat use, which confirmed the occurrence of social niche partitioning on the feeding grounds of this baleen whale. In addition, we document the extensive practice of group bubble net feeding in Pacific Canada. This coordinated feeding behavior was found to strongly mediate the social structure and habitat use within this humpback whale society. Additionally, during our 2004 – 2019 study, we observed a shift in social network structure in 2010 – 2012, which corresponded with environmental and demographic shifts including a sudden decline in the population’s calving rate. Our findings indicate that the social lives of humpback whales, and perhaps baleen whales generally, are more complex than previously supposed and should be a primary consideration in the assessment of potential impacts to important habitat.

scholarly journals Direct and indirect effects of minke whale abundance on cod and herring fisheries: A scenario experiment for the Greater Barents Sea

2000 ◽  
Vol 2 ◽  
pp. 120 ◽  
Author(s):  
Tore Schweder ◽  
Gro S Hagen ◽  
Einar Hatlebakk
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Minke Whale ◽  
Clupea Harengus ◽  
Prey Abundance ◽  
Balaenoptera Acutorostrata ◽  
Time Step ◽  
Minke Whales ◽  
Spawning Stock ◽  
Capelin Mallotus Villosus

To study the pattern of interaction between minke whale (Balaenoptera acutorostrata) abundance and the main fisheries in the Greater Barents Sea, a simulation experiment was carried out. The population model involves 4 species interconnected in a food web: cod (Gadus morhua), capelin (Mallotus villosus), herring (Clupea harengus) and minke whales. Minke whales are preying on cod, capelin andherring; cod are preying on (young) cod, capelin and herring; herring in the Barents Sea are preying on capelin; while capelin is a bottom prey in the model. The consumption function for minke whales is non-linear in available prey abundance, and is estimated from stomach content data and prey abundance data. The model is dynamic, with a time step of one month, and there are two areas: the BarentsSea and the Norwegian Sea. Minke whale abundances are kept on fixed levels, while recruitment in fish is stochastic.Cod and herring fisheries are managed by quotas targeting fixed fishing mortalities, while capelin is managed with a view to allow the cod to have enough food and leaving a sufficient spawning stock of capelin. The model is simulated over a period of 100 years for a number of fixed levels of minke whaleabundance, and simulated catches of cod, herring and capelin are recorded.The experiment showed interactions between whale abundance and fish catches to be mainly linear. For cod catches, both the direct effect of whales consuming cod, and the indirect effect due to whales competing with cod for food and otherwise altering the ecosystem, are linear and of equal importance. The net effect on the herring fishery is of the same magnitude as the net effect on the cod fishery, witheach extra whale reducing the catches of both species by some 5 tonnes. These conclusions are conditional on the model and its parameterisation.

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