Marine mammals and Japanese long-line fishing vessels in Australian waters: operational interactions and sightings

2006 ◽  
Vol 12 (1) ◽  
pp. 31 ◽  
Author(s):  
Catherine Bell ◽  
Peter Shaughnessy ◽  
Margie Morrice ◽  
Bob Stanley
Keyword(s):  
Marine Mammal ◽  
Marine Mammals ◽  
East Coast ◽  
Fishing Gear ◽  
Killer Whales ◽  
Fishing Vessels ◽  
Long Line ◽  
Target Fish ◽  
Pilot Whales ◽  
Warm Temperate

Observers from the Australian Fisheries Management Authority worked on randomly chosen Japanese long-line vessels in the Australian Fishing Zone (AFZ) between 1980 and 1997. Observer reports (n = 451) were inspected for interactions or sightings of marine mammals. An operational interaction was defined as an activity or behaviour that involved direct contact between a marine mammal and fishing gear, bait, target fish or bycatch, or indications that the marine mammal was feeding. A sighting was defined as the recording of marine mammals that passed the vessel without changing course and/or did not appear to interact with the vessel or its gear. Observers witnessed 23 interactions and made another 44 sightings of marine mammals. A further 24 interactions and sightings were relayed by crew members. Killer whales were reported most frequently: most incidences of fish being damaged, taken or frightened away were attributed to them. Eleven marine mammals were caught: two died, seven were released, and the fate of two others was not recorded. Between 1991 and 1996, when observer coverage was 11.5% overall in the AFZ, the incidence of interactions was 1.71 per million hooks set. The estimated number of interactions in that seven-year period was 157 in the AFZ. Since 1997, the long-line fishery has been conducted by Australian vessels, primarily off the east coast of mainland Australia in warm-temperate waters. A higher proportion of interactions can be expected with killer whales and short-finned pilot whales in these waters, and fewer with seals.

scholarly journals Resurgence of an apex marine predator and the decline in prey body size

2019 ◽  
Vol 116 (52) ◽  
pp. 26682-26689 ◽  
Author(s):  
Jan Ohlberger ◽  
Daniel E. Schindler ◽  
Eric J. Ward ◽  
Timothy E. Walsworth ◽  
Timothy E. Essington
Keyword(s):  
Life History ◽  
Body Size ◽  
Chinook Salmon ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Size Structure ◽  
Economic Value ◽  
Killer Whales ◽  
Selective Predation ◽  
Marine Predator

In light of recent recoveries of marine mammal populations worldwide and heightened concern about their impacts on marine food webs and global fisheries, it has become increasingly important to understand the potential impacts of large marine mammal predators on prey populations and their life-history traits. In coastal waters of the northeast Pacific Ocean, marine mammals have increased in abundance over the past 40 to 50 y, including fish-eating killer whales that feed primarily on Chinook salmon. Chinook salmon, a species of high cultural and economic value, have exhibited marked declines in average size and age throughout most of their North American range. This raises the question of whether size-selective predation by marine mammals is generating these trends in life-history characteristics. Here we show that increased predation since the 1970s, but not fishery selection alone, can explain the changes in age and size structure observed for Chinook salmon populations along the west coast of North America. Simulations suggest that the decline in mean size results from the selective removal of large fish and an evolutionary shift toward faster growth and earlier maturation caused by selection. Our conclusion that intensifying predation by fish-eating killer whales contributes to the continuing decline in Chinook salmon body size points to conflicting management and conservation objectives for these two iconic species.

scholarly journals Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective

2009 ◽  
Vol 364 (1524) ◽  
pp. 1647-1658 ◽  
Author(s):  
J.A. Estes ◽  
D.F. Doak ◽  
A.M. Springer ◽  
T.M. Williams
Keyword(s):  
World War Ii ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Marine Ecosystem ◽  
Kelp Forests ◽  
Sea Otter ◽  
Population Declines ◽  
Killer Whales ◽  
Sea Otters ◽  
Coastal Marine

Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal marine ecosystem underwent a phase shift from kelp forests to deforested sea urchin barrens. This interaction in turn affected the distribution, abundance and productivity of numerous other species. Ecological consequences of the pinniped declines are largely unknown. Increased predation by transient (marine mammal-eating) killer whales probably caused the sea otter declines and may have caused the pinniped declines as well. Springer et al . proposed that killer whales, which purportedly fed extensively on great whales, expanded their diets to include a higher percentage of sea otters and pinnipeds following a sharp reduction in great whale numbers from post World War II industrial whaling. Critics of this hypothesis claim that great whales are not now and probably never were an important nutritional resource for killer whales. We used demographic/energetic analyses to evaluate whether or not a predator–prey system involving killer whales and the smaller marine mammals would be sustainable without some nutritional contribution from the great whales. Our results indicate that while such a system is possible, it could only exist under a narrow range of extreme conditions and is therefore highly unlikely.

scholarly journals Marine mammal skin microbiotas are influenced by host phylogeny

2020 ◽  
Vol 7 (5) ◽  
pp. 192046 ◽  
Author(s):  
Amy Apprill ◽  
Carolyn A. Miller ◽  
Amy M. Van Cise ◽  
Jana M. U'Ren ◽  
Matthew S. Leslie ◽  
...  
Keyword(s):  
Marine Mammal ◽  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
The United States ◽  
Small Subunit ◽  
Sperm Whales ◽  
Animal Group ◽  
Host Phylogeny ◽  
Pilot Whales ◽  
Free Ranging

Skin-associated microorganisms have been shown to play a role in immune function and disease of humans, but are understudied in marine mammals, a diverse animal group that serve as sentinels of ocean health. We examined the microbiota associated with 75 epidermal samples opportunistically collected from nine species within four marine mammal families, including: Balaenopteridae (sei and fin whales), Phocidae (harbour seal), Physeteridae (sperm whales) and Delphinidae (bottlenose dolphins, pantropical spotted dolphins, rough-toothed dolphins, short-finned pilot whales and melon-headed whales). The skin was sampled from free-ranging animals in Hawai‘i (Pacific Ocean) and off the east coast of the United States (Atlantic Ocean), and the composition of the bacterial community was examined using the sequencing of partial small subunit (SSU) ribosomal RNA genes. Skin microbiotas were significantly different among host species and taxonomic families, and microbial community distance was positively correlated with mitochondrial-based host genetic divergence. The oceanic location could play a role in skin microbiota variation, but skin from species sampled in both locations is necessary to determine this influence. These data suggest that a phylosymbiotic relationship may exist between microbiota and their marine mammal hosts, potentially providing specific health and immune-related functions that contribute to the success of these animals in diverse ocean ecosystems.

scholarly journals MODEL ESTIMASI KONSUMSI BAHAN BAKAR KAPAL IKAN HUHATE DAN RAWAI TUNA

2017 ◽  
Vol 23 (2) ◽  
pp. 99
Author(s):  
Suryanto Suryanto ◽  
Wudianto Wudianto
Keyword(s):  
Fuel Consumption ◽  
Fuel Oil ◽  
Production Factor ◽  
Fishing Gear ◽  
Oil Consumption ◽  
Estimation Model ◽  
Indonesian Seas ◽  
Fishing Vessels ◽  
Long Line ◽  
The Government

Huhate dan rawai tuna merupakan alat tangkap utama untuk menangkap ikan tuna di perairan Indonesia. Hasil tangkapannya harus bersaing dalam perdagangan global dimana biaya bahan bakar merupakan faktor produksi yang dominan. Namun kebijakan Pemerintah terkait subsidi bahan bakar minyak terlalu sering berubah karena keterbatasan kemampuan keuangan Pemerintah. Disisi lain peraturan subsidi bahan bakar kapal perikanan yang berlaku kurang mencerminkan kondisi nyata armada perikanan Nasional. Oleh karena itu, perkiraan konsumsi bahan bakar yang diperlukan harus dilakukan secara cermat. Penelitian ini bertujuan untuk mengembangkan model estimasi konsumsi BBM mesin induk dan mesin bantu, khususnya untuk armada huhate dan rawai tuna. Uji model Kleppesto, Digernes dan Hollenbach digunakan untuk mengestimasi daya mesin induk armada huhate dan rawai tuna berdasarkan data SIPI (Surat Ijin Penangkapan Ikan) dan pengukuran kecepatan kapal dilapangan. Hasil penelitian menunjukan bahwa model Kleppesto mendapatkan hasil lebih akurat. Selanjutnya model ini dipakai untuk memperkirakan faktor konsumsi BBM mesin induk dan mesin bantu (Cbbm) dengan 2 skenario efisiensi quasi propulsive optimis dan pesimis. Hasil penelitian menunjukan, dengan kedua skenario tersebut, Cbbm armada huhate dan rawai tuna didapatkan nilai 0,121-0,160 dan 0,136-0,180 (kg/HP.jam). Hal ini menjelaskan bahwa untuk mendapatkan faktor konsumsi BBM kapal ikan perlu memperhatikan jenis alat tangkap ikan yang digunakan. Pole and line and long line are main fishing gear for catching tuna in Indonesian seas. Their catches must compete in global trade where as fuel cost is a dominant production factor. However the Government’s policy on fuel subsidies has changed too often due to the limited financial capacity of the Government. In addition, the present regulation of fuel subsidy for fishing vessels does not reflect the real condition of the national fishing fleet. Thus, the estimation of the required fuel consumption must be done carefully. This paper aims to develop fuel consumption estimation model for pole and liner and tuna longliner. Based on the data of fishing licences and in situ vessel speeds measurements; Kleppesto, Digernes and Hollenbach models were used to estimate the required engine power of pole and liner and tuna longliner samples. The study indicates that Kleppesto model is more accurate compared to the other two. Using the scenario of optimistic and pessimistic quasi propulsive efficiencies, then the models were used to estimate the fuel oil consumption factor for main and auxiliary engines (Cbbm) of the fleets. The research shows, Cbbm of pole and liner and tuna longliner are 0,121-0,160 dan 0,136-0,180 (kg/HP.jam)  respectively. The result showed that fuel oil consumption factor of fishing vessel depends on fishing gear used.

scholarly journals Killer whales are attracted to herring fishing vessels

2020 ◽  
Vol 652 ◽  
pp. 1-13
Author(s):  
E Mul ◽  
MA Blanchet ◽  
BT McClintock ◽  
WJ Grecian ◽  
M Biuw ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Fishery Management ◽  
Killer Whale ◽  
Detailed Knowledge ◽  
Killer Whales ◽  
Fishing Activity ◽  
Fishing Vessels ◽  
Satellite Transmitters ◽  
Core Areas ◽  
The Impact

Marine mammals and fisheries often target the same resources, which can lead to operational interactions. Potential consequences of operational interaction include entanglements and damaged or reduced catches but also enhanced foraging opportunities, which can attract marine mammals to fishing vessels. Responsible fisheries management therefore requires detailed knowledge of the impact of these interactions. In northern Norway, killer whales Orcinus orca are frequently observed in association with large herring aggregations during the winter. We use a combination of biotelemetry and fisheries data to study if, to what extent and at what distances killer whales are attracted to fishing activity. Twenty-five satellite transmitters were deployed on killer whales at herring overwintering and spawning grounds, often near fishing vessels. Over 50% of the killer whale core areas of high usage overlapped with the fisheries core areas, and individual whales spent up to 34% of their time close to active fishing. We used a 3-state hidden Markov model to assess whether killer whale movements were biased towards fishing activities. Of the overall whale movements, 15% (CI = 11-21%) were biased towards fishing activities, with marked heterogeneity among individuals (0-57%). During periods of active fishing, whale movements were biased towards fishing events 44% (CI = 24-66%) of the time, with individual percentages ranging from 0 to 79%. Whales were more likely to be attracted when they were within 20 km. This information can be used in fishery management to consider potential consequences for fishers and whales.

Recommendations for Sustainable Cetacean-Based Tourism in French Territories: A Review on the Industry and Current Management Actions

2020 ◽  
Vol 15 (3) ◽  
pp. 211-235
Author(s):  
Josephine Chazot ◽  
Ludovic Hoarau ◽  
Pamela Carzon ◽  
Jeanne Wagner ◽  
Stéphanie Sorby ◽  
...  
Keyword(s):  
Marine Mammal ◽  
Marine Mammals ◽  
French Polynesia ◽  
Legal Framework ◽  
Whale Watching ◽  
Cetacean Species ◽  
Commercial Activities ◽  
Management Actions ◽  
Overseas Territories ◽  
Socioeconomic Benefits

Whale-watching activities provide important socioeconomic benefits for local communities and constitute powerful platform incentives for marine mammals' protection or more broadly marine environments. However, these activities can cause adverse effects on targeted populations, with considerable downside associated risks of injuries and fatality for whale watchers during inwater interactions. France with its overseas territories has the second largest exclusive economic zone (EEZ), in which more than half of existing cetacean species are encountered. In these territories, recreational and commercial whale watching, including swim-with cetacean activities, have recently developed. Yet few studies focused on these activities and their associated impacts across French territories, leading to an unclear assessment of the situation. To address this issue, we reviewed cetaceans' occurrence within the French EEZ, whale-watching industry, targeted species, local management of marine mammal-based tourism activities, and regulations in France mainland and some overseas territories (Reunion Island, Mayotte, and French Polynesia). Fortyeight species are encountered in the French EEZ, and 15 are targeted by whale-watching activities. A total of 185 operators, including 34% offering swim-with-cetaceans tours, offered trips in France and overseas in 2019. While several more or less restrictive regulations exist locally, our results indicate that French's national legal framework for marine mammals' protection remains inadequate and insufficient to cope with the recent development of this activity. As conservation biologists, managers, and stakeholders from these French territories, we cooperated to provide general guidelines for a sustainable development of whale watching at a national scale. We urge (1) to legally acknowledge and regulate whale-watching commercial activities; (2) to create a national legal framework regarding whale watching and swim-with marine mammals practices, while accounting for local distinctiveness and disparities across regions; (3) to conduct more research to evaluate local short- and long-term impacts on targeted marine mammal populations as well as the socioeconomic benefits; and (4) to reinforce synergetic relations between the different stakeholders.

First record of Norwegian killer whales attacking and feeding on a harbour porpoise

2015 ◽  
Vol 8 ◽  
Author(s):  
A. Mel Cosentino
Keyword(s):  
North Atlantic ◽  
Marine Mammals ◽  
First Record ◽  
Harbour Porpoise ◽  
Sperm Whales ◽  
Killer Whales ◽  
Strait Of Gibraltar ◽  
Cetacean Species ◽  
The North ◽  
Northern Bottlenose Whales

Orcinus orcais a cosmopolitan species and the most widely distributed marine mammal. Its diet includes over 140 species of fish, cephalopods, sea birds and marine mammals. However, many populations are specialised on certain specific prey items. Three genetically distinct populations have been described in the North Atlantic. Population A (that includes the Icelandic and Norwegian sub-populations) is believed to be piscivorous, as is population C, which includes fish-eating killer whales from the Strait of Gibraltar. In contrast, population B feeds on both fish and marine mammals. Norwegian killer whales follow the Norwegian spring spawning herring stock. The only description in the literature of Norwegian killer whales feeding on another cetacean species is a predation event on northern bottlenose whales in 1968. Daily land-based surveys targeting sperm whales were conducted from the Andenes lighthouse using BigEyes®binoculars (25×, 80 mm). The location of animals at sea was approximated through the use of an internal reticule system and a graduated wheel. On 24 June 2012 at 3:12 am, an opportunistic sighting of 11 killer whales was made off Andenes harbour. The whales hunted and fed on a harbour porpoise. Despite these species having overlapping distributions in Norwegian waters, this is the first predatory event reported in the literature.

scholarly journals Effects of a scientific echo sounder on the behavior of short-finned pilot whales (Globicephala macrorhynchus)

2017 ◽  
Vol 74 (5) ◽  
pp. 716-726 ◽  
Author(s):  
Nicola Quick ◽  
Lindesay Scott-Hayward ◽  
Dina Sadykova ◽  
Doug Nowacek ◽  
Andrew Read
Keyword(s):  
North Carolina ◽  
Generalized Estimating Equations ◽  
Marine Mammals ◽  
Hidden Markov ◽  
Experimental Conditions ◽  
Cape Hatteras ◽  
Consistent Increase ◽  
Pilot Whales ◽  
Acoustic Recording ◽  
Echo Sounder

Active echo sounding devices are often employed for commercial or scientific purposes in the foraging habitats of marine mammals. We conducted an experiment off Cape Hatteras, North Carolina, USA, to assess whether the behavior of short-finned pilot whales (Globicephala macrorhynchus) changed when exposed to an EK60 scientific echo sounder. We attached digital acoustic recording tags (DTAGs) to nine individuals, five of which were exposed. A hidden Markov model to characterize diving states with and without exposure provided no evidence for a change in foraging behavior. However, generalized estimating equations to model changes in heading variance over the entire tag record under all experimental conditions showed a consistent increase in heading variance during exposure over all values of depth and pitch. This suggests that regardless of behavioral state, the whales changed their heading more frequently when the echo sounder was active. This response could represent increased vigilance in which whales maintained awareness of echo sounder location by increasing their heading variance and provides the first quantitative analysis on reactions of cetaceans to a scientific echo sounder.

scholarly journals Estimates of Chinook salmon consumption in Washington State inland waters by four marine mammal predators from 1970 to 2015

2017 ◽  
Vol 74 (8) ◽  
pp. 1173-1194 ◽  
Author(s):  
Brandon Chasco ◽  
Isaac C. Kaplan ◽  
Austen Thomas ◽  
Alejandro Acevedo-Gutiérrez ◽  
Dawn Noren ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Marine Mammal ◽  
Oncorhynchus Tshawytscha ◽  
Interspecific Interactions ◽  
Puget Sound ◽  
The United States ◽  
Washington State ◽  
Killer Whales ◽  
Protected Species ◽  
Annual Biomass

Conflicts can arise when the recovery of one protected species limits the recovery of another through competition or predation. The recovery of many marine mammal populations on the west coast of the United States has been viewed as a success; however, within Puget Sound in Washington State, the increased abundance of three protected pinniped species may be adversely affecting the recovery of threatened Chinook salmon (Oncorhynchus tshawytscha) and endangered killer whales (Orcinus orca) within the region. Between 1970 and 2015, we estimate that the annual biomass of Chinook salmon consumed by pinnipeds has increased from 68 to 625 metric tons. Converting juvenile Chinook salmon into adult equivalents, we found that by 2015, pinnipeds consumed double that of resident killer whales and six times greater than the combined commercial and recreational catches. We demonstrate the importance of interspecific interactions when evaluating species recovery. As more protected species respond positively to recovery efforts, managers should attempt to evaluate tradeoffs between these recovery efforts and the unintended ecosystem consequences of predation and competition on other protected species.

Sign in / Sign up

Export Citation Format

Share Document