Anderson, Charles,Herrera, Miguel,Ilangakoon, Anoukchika,Koya, KM,Moazzam, M,Mustika, Putu L,Sutaria, Dipani N
Cetacean bycatch in Indian Ocean tuna gillnet fisheries Journal Article
In: Endangered Species Research, vol. 41, no. 292, pp. 39-53, 2020, ISSN: 1863-5407.
Abstract | Links | BibTeX | Tags: Bycatch, Estimates, Extrapolation, Gill net, gillnet, Indian Ocean, mortality, Observer programmes, Oman, Pakistan, Sri Lanka, Trends, tuna fishery
@article{,
title = {Cetacean bycatch in Indian Ocean tuna gillnet fisheries},
author = {Anderson, Charles,Herrera, Miguel,Ilangakoon, Anoukchika,Koya, KM,Moazzam, M,Mustika, Putu L,Sutaria, Dipani N},
url = {https://www.int-res.com/prepress/n01008.html},
doi = {https://doi.org/10.3354/esr01008},
issn = {1863-5407},
year = {2020},
date = {2020-01-01},
journal = {Endangered Species Research},
volume = {41},
number = {292},
pages = {39-53},
abstract = {Pelagic gillnet (driftnet) fisheries account for some 34% of Indian Ocean tuna catches. We combine published results from 10 bycatch sampling programmes (1981–2016) in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans across all Indian Ocean tuna gillnet fisheries. Estimated cetacean bycatch peaked at almost 100,000 individuals yr–1 during 2004–2006, but has declined by over 15% since then, despite an increase in tuna gillnet fishing effort. These fisheries caught an estimated cumulative total of 4.1 million small cetaceans between 1950 and 2018. These bycatch estimates take little or no account of cetaceans caught by gillnet but not landed, of delayed mortality or sub-lethal impacts on cetaceans (especially whales) that escape from gillnets, of mortality associated with ghost nets, of harpoon catches made from gillnetters, nor of mortality from other tuna fisheries. Total cetacean mortality from Indian Ocean tuna fisheries may therefore be substantially higher than estimated here. Declining cetacean bycatch rates suggest that such levels of mortality are not sustainable. Indeed, mean small cetacean abundance may currently be 13% of pre-fishery levels. None of these estimates are precise, but they do demonstrate the likely order of magnitude of the issue. Countries with the largest current gillnet catches of tuna, and thus the ones likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania. These 9 countries together may account for roughly 96% of all cetacean bycatch from tuna gillnet fisheries across the Indian Ocean. },
keywords = {Bycatch, Estimates, Extrapolation, Gill net, gillnet, Indian Ocean, mortality, Observer programmes, Oman, Pakistan, Sri Lanka, Trends, tuna fishery},
pubstate = {published},
tppubtype = {article}
}
Pelagic gillnet (driftnet) fisheries account for some 34% of Indian Ocean tuna catches. We combine published results from 10 bycatch sampling programmes (1981–2016) in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans across all Indian Ocean tuna gillnet fisheries. Estimated cetacean bycatch peaked at almost 100,000 individuals yr–1 during 2004–2006, but has declined by over 15% since then, despite an increase in tuna gillnet fishing effort. These fisheries caught an estimated cumulative total of 4.1 million small cetaceans between 1950 and 2018. These bycatch estimates take little or no account of cetaceans caught by gillnet but not landed, of delayed mortality or sub-lethal impacts on cetaceans (especially whales) that escape from gillnets, of mortality associated with ghost nets, of harpoon catches made from gillnetters, nor of mortality from other tuna fisheries. Total cetacean mortality from Indian Ocean tuna fisheries may therefore be substantially higher than estimated here. Declining cetacean bycatch rates suggest that such levels of mortality are not sustainable. Indeed, mean small cetacean abundance may currently be 13% of pre-fishery levels. None of these estimates are precise, but they do demonstrate the likely order of magnitude of the issue. Countries with the largest current gillnet catches of tuna, and thus the ones likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania. These 9 countries together may account for roughly 96% of all cetacean bycatch from tuna gillnet fisheries across the Indian Ocean.
NOAA
Taking and Importing of Marine Mammals and Dolphin-Safe Tuna Products Journal Article
In: Federal Register, vol. 81, no. 421, pp. 3, 2016.
Abstract | BibTeX | Tags: Arabian Sea, Bycatch, Fisheries, India, Marine mammals, NIO, Observer programmes, Oman, Pakistan, reporting scheme, Tanzania, tuna fishery
@article{,
title = {Taking and Importing of Marine Mammals and Dolphin-Safe Tuna Products },
author = {NOAA},
year = {2016},
date = {2016-01-01},
journal = {Federal Register},
volume = {81},
number = {421},
pages = {3},
abstract = { The Assistant Administrator
for Fisheries, NMFS, (Assistant
Administrator) has issued a
determination, under the Dolphin
Protection Consumer Information Act
(DPCIA), of regular and significant
mortality and serious injury of dolphins
in gillnet fisheries harvesting tuna by
vessels flagged under the Governments
of India, Iran, Mozambique, Pakistan,
Oman, Saudi Arabia, Sri Lanka,
Tanzania, the United Arab Emirates,
and Yemen. This determination triggers
additional documentation requirements
for tuna product from those fisheries
that is exported from or offered for sale
in the United States, including that such
tuna must be accompanied by a written
statement executed by an observer
participating in a national or
international program acceptable to the
Assistant Administrator, in addition to
such statement by the captain of the
vessel, that certifies that no dolphins
were killed or seriously injured in the
sets or other gear deployments in which
the tuna were caught and certain other
required information regarding dolphin
interactions and segregation of tuna.
These determinations were based on
review of scientific information and,
when available, documentary evidence
submitted by the relevant government. },
keywords = {Arabian Sea, Bycatch, Fisheries, India, Marine mammals, NIO, Observer programmes, Oman, Pakistan, reporting scheme, Tanzania, tuna fishery},
pubstate = {published},
tppubtype = {article}
}
The Assistant Administrator
for Fisheries, NMFS, (Assistant
Administrator) has issued a
determination, under the Dolphin
Protection Consumer Information Act
(DPCIA), of regular and significant
mortality and serious injury of dolphins
in gillnet fisheries harvesting tuna by
vessels flagged under the Governments
of India, Iran, Mozambique, Pakistan,
Oman, Saudi Arabia, Sri Lanka,
Tanzania, the United Arab Emirates,
and Yemen. This determination triggers
additional documentation requirements
for tuna product from those fisheries
that is exported from or offered for sale
in the United States, including that such
tuna must be accompanied by a written
statement executed by an observer
participating in a national or
international program acceptable to the
Assistant Administrator, in addition to
such statement by the captain of the
vessel, that certifies that no dolphins
were killed or seriously injured in the
sets or other gear deployments in which
the tuna were caught and certain other
required information regarding dolphin
interactions and segregation of tuna.
These determinations were based on
review of scientific information and,
when available, documentary evidence
submitted by the relevant government.
for Fisheries, NMFS, (Assistant
Administrator) has issued a
determination, under the Dolphin
Protection Consumer Information Act
(DPCIA), of regular and significant
mortality and serious injury of dolphins
in gillnet fisheries harvesting tuna by
vessels flagged under the Governments
of India, Iran, Mozambique, Pakistan,
Oman, Saudi Arabia, Sri Lanka,
Tanzania, the United Arab Emirates,
and Yemen. This determination triggers
additional documentation requirements
for tuna product from those fisheries
that is exported from or offered for sale
in the United States, including that such
tuna must be accompanied by a written
statement executed by an observer
participating in a national or
international program acceptable to the
Assistant Administrator, in addition to
such statement by the captain of the
vessel, that certifies that no dolphins
were killed or seriously injured in the
sets or other gear deployments in which
the tuna were caught and certain other
required information regarding dolphin
interactions and segregation of tuna.
These determinations were based on
review of scientific information and,
when available, documentary evidence
submitted by the relevant government.
Escalle, L.,Capietto, A.,Chavance, P.,Dubroca, L.,Delgado De Molina, A.,Murua, H.,Gaertner, D.,Romanov, E.,Spitz, J.,Kiszka, J. J.,Floch, L.,Damiano, A.,Merigot, B.
Cetaceans and tuna purse seine fisheries in the Atlantic and Indian Oceans: interactions but few mortalities Journal Article
In: Marine Ecology Progress Series, vol. 522, no. 370, pp. 255-268, 2015.
Abstract | Links | BibTeX | Tags: Atlantic, Bycatch, cetaceans, Humpback Whale, Indian Ocean, megaptera novaeangliae, purse-Seine, tuna fishery
@article{,
title = {Cetaceans and tuna purse seine fisheries in the Atlantic and Indian Oceans: interactions but few mortalities},
author = {Escalle, L.,Capietto, A.,Chavance, P.,Dubroca, L.,Delgado De Molina, A.,Murua, H.,Gaertner, D.,Romanov, E.,Spitz, J.,Kiszka, J. J.,Floch, L.,Damiano, A.,Merigot, B.},
url = {http://www.int-res.com/abstracts/meps/v522/p255-268/},
year = {2015},
date = {2015-01-01},
journal = {Marine Ecology Progress Series},
volume = {522},
number = {370},
pages = {255-268},
abstract = {ABSTRACT: Fisheries bycatch is considered to be one of the most significant causes of mortality for many marine species, including vulnerable megafauna. In the open ocean, tuna purse seiners are known to use several cetacean species to detect tuna schools. This exposes the cetaceans to encirclement which can lead to incidental injury or death. While interactions between fishers and cetaceans have been well documented in the eastern tropical Pacific Ocean, little is known about these interactions and potential mortalities in the tropical Atlantic and Indian Oceans. Here, we provide the first quantification of these interactions in both oceans by analyzing a large database of captain’s logbooks (1980 to 2011) and observations collected by onboard scientific observers (1995 to 2011). Distribution maps of sightings per unit effort highlighted main areas of relatively high co-occurrence: east of the Seychelles (December to March), the Mozambique Channel (April to May) and the offshore waters of Gabon (April to September). The percentage of cetacean-associated fishing sets was around 3% in both oceans and datasets whereas 0.6% of sets had cetaceans encircled. Of the 194 cetaceans encircled in a purse seine net (122 baleen whales, 72 delphinids), immediate apparent survival rates were high (Atlantic: 92%, Indian: 100%). Among recorded mortalities, 8 involved pantropical spotted dolphins \textit{Stenella attenuata} and 3 involved humpback whales \textit{Megaptera novaeangliae}. These high survival rates suggest that setting nets close to cetaceans has a low immediate apparent impact on the species involved. Our findings will contribute to the development of an ecosystem approach to managing fisheries and accurate cetacean conservation measures.},
keywords = {Atlantic, Bycatch, cetaceans, Humpback Whale, Indian Ocean, megaptera novaeangliae, purse-Seine, tuna fishery},
pubstate = {published},
tppubtype = {article}
}
ABSTRACT: Fisheries bycatch is considered to be one of the most significant causes of mortality for many marine species, including vulnerable megafauna. In the open ocean, tuna purse seiners are known to use several cetacean species to detect tuna schools. This exposes the cetaceans to encirclement which can lead to incidental injury or death. While interactions between fishers and cetaceans have been well documented in the eastern tropical Pacific Ocean, little is known about these interactions and potential mortalities in the tropical Atlantic and Indian Oceans. Here, we provide the first quantification of these interactions in both oceans by analyzing a large database of captain’s logbooks (1980 to 2011) and observations collected by onboard scientific observers (1995 to 2011). Distribution maps of sightings per unit effort highlighted main areas of relatively high co-occurrence: east of the Seychelles (December to March), the Mozambique Channel (April to May) and the offshore waters of Gabon (April to September). The percentage of cetacean-associated fishing sets was around 3% in both oceans and datasets whereas 0.6% of sets had cetaceans encircled. Of the 194 cetaceans encircled in a purse seine net (122 baleen whales, 72 delphinids), immediate apparent survival rates were high (Atlantic: 92%, Indian: 100%). Among recorded mortalities, 8 involved pantropical spotted dolphins Stenella attenuata and 3 involved humpback whales Megaptera novaeangliae. These high survival rates suggest that setting nets close to cetaceans has a low immediate apparent impact on the species involved. Our findings will contribute to the development of an ecosystem approach to managing fisheries and accurate cetacean conservation measures.
Romanov, Evgeny V
Bycatch in the tuna purse-seine fisheries of the western Indian Ocean Journal Article
In: Fishery Bulletin, vol. 100, no. 455, pp. 90-105, 2002, ISBN: 0090-0656.
Abstract | BibTeX | Tags: balaenoptera, Bryde’s whale, Bycatch, Indian Ocean, purse-Seine, tuna fishery
@article{,
title = {Bycatch in the tuna purse-seine fisheries of the western Indian Ocean},
author = {Romanov, Evgeny V},
issn = {0090-0656},
year = {2002},
date = {2002-01-01},
journal = {Fishery Bulletin},
volume = {100},
number = {455},
pages = {90-105},
abstract = {Bycatch taken by the tuna purse-seine fishery from the Indian Ocean pelagic ecosystem was estimated from data collected by scientific observers aboard Soviet purse seiners in the western Indian Ocean (WIO) during 1986–92. A total of 494 sets on free-swimming schools, whale-shark-associated schools, whale-associated schools, and log-associated schools were analyzed. More than 40 fish species and other marine animals were recorded. Among them only two species, yellow-fin and skipjack tunas, were target species. Average levels of bycatch were 0.518 metric tons (t) per set, and 27.1 t per 1000 t of target species. The total annual purse-seine catch of yellowfin and skipjack tunas by principal fishing nations in the WIO during 1985–94 was 118,000–277,000 t. Nonrecorded annual bycatch for this period was estimated at 944–2270 t of pelagic oceanic sharks, 720–1877 t of rainbow runners, 705–1836 t of dolphinfishes, 507–1322 t of triggerfishes, 113–294 t of wahoo, 104–251 t of billfishes, 53–112 t of mobulas and mantas, 35–89 t of mackerel scad, 9–24 t of barracudas, and 67–174 t of other fishes. In addition, turtle bycatch and whale mortalities may have occurred. Because the bycatches were not recorded by some purse-seine vessels, it was not possible to assess the full impact of the fisheries on the pelagic ecosystem of the Indian Ocean. The first step to solving this problem is for the Indian Ocean Tuna Commission to establish a pro-gram in which scientific observers are placed on board tuna purse-seine and longline vessels fishing in the WIO.},
keywords = {balaenoptera, Bryde’s whale, Bycatch, Indian Ocean, purse-Seine, tuna fishery},
pubstate = {published},
tppubtype = {article}
}
Bycatch taken by the tuna purse-seine fishery from the Indian Ocean pelagic ecosystem was estimated from data collected by scientific observers aboard Soviet purse seiners in the western Indian Ocean (WIO) during 1986–92. A total of 494 sets on free-swimming schools, whale-shark-associated schools, whale-associated schools, and log-associated schools were analyzed. More than 40 fish species and other marine animals were recorded. Among them only two species, yellow-fin and skipjack tunas, were target species. Average levels of bycatch were 0.518 metric tons (t) per set, and 27.1 t per 1000 t of target species. The total annual purse-seine catch of yellowfin and skipjack tunas by principal fishing nations in the WIO during 1985–94 was 118,000–277,000 t. Nonrecorded annual bycatch for this period was estimated at 944–2270 t of pelagic oceanic sharks, 720–1877 t of rainbow runners, 705–1836 t of dolphinfishes, 507–1322 t of triggerfishes, 113–294 t of wahoo, 104–251 t of billfishes, 53–112 t of mobulas and mantas, 35–89 t of mackerel scad, 9–24 t of barracudas, and 67–174 t of other fishes. In addition, turtle bycatch and whale mortalities may have occurred. Because the bycatches were not recorded by some purse-seine vessels, it was not possible to assess the full impact of the fisheries on the pelagic ecosystem of the Indian Ocean. The first step to solving this problem is for the Indian Ocean Tuna Commission to establish a pro-gram in which scientific observers are placed on board tuna purse-seine and longline vessels fishing in the WIO.