Mark R. Christie1*, Brian N. Tissot2, Mark A. Albins1, James P. Beets3, Yanli Jia4, Delisse M. Ortiz5, Stephen E. Thompson6, Mark A. Hixon1
1 Department of Zoology, Oregon State University, Corvallis, Oregon, United States of America, 2 School of Earth and Environmental Science, Washington State University, Vancouver, Washington, United States of America, 3 Department of Marine Science, University of Hawaii at Hilo, Hilo, Hawaii, United States of America, 4 International Pacific Research Center, University of Hawaii, Honolulu, Hawaii, United States of America, 5 National Marine Fisheries Service, Highly Migratory Species Management Division, Silver Spring, Maryland, United States of America, 6 Marine Environmental Research, Kailua-Kona, Hawaii, United States of America
Abstract
Acceptance of marine protected areas (MPAs) as fishery and conservation tools has been hampered by lack of direct evidence that MPAs successfully seed unprotected areas with larvae of targeted species. For the first time, we present direct evidence of large-scale population connectivity within an existing and effective network of MPAs. A new parentage analysis identified four parent-offspring pairs from a large, exploited population of the coral-reef fish Zebrasoma flavescens in Hawai'i, revealing larval dispersal distances ranging from 15 to 184 km. In two cases, successful dispersal was from an MPA to unprotected sites. Given high adult abundances, the documentation of any parent-offspring pairs demonstrates that ecologically-relevant larval connectivity between reefs is substantial. All offspring settled at sites to the north of where they were spawned. Satellite altimetry and oceanographic models from relevant time periods indicated a cyclonic eddy that created prevailing northward currents between sites where parents and offspring were found. These findings empirically demonstrate the effectiveness of MPAs as useful conservation and management tools and further highlight the importance of coupling oceanographic, genetic, and ecological data to predict, validate and quantify larval connectivity among marine populations.
Read more: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0015715
Kamis, 12 Mei 2011
Overfished bluefin tuna's status should be endangered
Overfished bluefin tuna's status should be endangered: experts
Advisers say spawning fish declined by 68 per cent over 2.5 generations
By Margaret Munro, Postmedia News May 10, 2011
Canada's top wildlife advisers say the Atlantic bluefin tuna, which has been known to fetch $1,000 per kilogram on sushi markets, is so overfished it should be listed as an endangered species.
But the Department of Fisheries and Oceans is in no hurry to stop the killing of the iconic fish in Maritime waters.
"Our Atlantic bluefin tuna fishery is the best managed fishery of its kind in the world today," Frank Stanek, DFO's manager of media relations, said by email when asked if the call for the endangered listing would put an end to the fishery. About 500 tonnes of the bluefin tuna were caught in Canadian waters last year.
"It would be premature to discuss the listing of these species under the Species at Risk Act before formal consultations with Canadians, further analysis of existing scientific information, and possible social and economic impacts are considered," Stanek said.
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) announced its bluefin tuna recommendation Monday when it released the grim status of several species that it says need protection under Species at Risk Act.
Alan Sinclair, who co-chaired the COSEWIC's bluefin assessment, said overfishing was identified as "the main threat" to bluefin tuna.
"It only makes sense to reduce fishing or to stop fishing altogether in order to reduce and eliminate this threat," he said.
Personally, Sinclair added, "I think Canadians should stop fishing this magnificent fish. It has been exploited for several decades; now it's time to give it every opportunity to recover."
COSEWIC includes experts from provincial, territorial, federal wildlife agencies, as well as aboriginal and public representatives. It met in Charlottetown, P.E.I., last week and its recommendations now go to the federal environment minister for listing consideration under the act.
If the bluefin is listed as endangered, it would put an end to the Canada's controversial bluefin tuna fishery.
The bluefin is one of the most highly sought-after fish in the world "with some market prices exceeding $1,000 per kilogram," the committee says.
"Unfortunately, its value has driven the species into a steep decline since the 1970s with recent abundance reaching an all-time low," said COSE-WIC, noting abundance of spawning fish has declined by 68 per cent over the past 2.5 generations.
Bluefin tuna are fished along the east coast of North America as they migrate to the Maritimes from their spawning grounds in the Gulf of Mexico.
And spawning tuna were exposed to Deepwater Horizon oil spill in the gulf last year.
"While the effects of the spill on the species are currently unknown, it may represent an additional threat," COSEWIC said.
The committee also raised alarm over several other species -from the once-common barn swallow to the oolichan, a small fish that used to be a cultural mainstay of many first nations people.
But the committee did have some good news, saying the humpback whale has made a comeback.
"The population off the Pacific coast is increasing steadily, was despite continuing threats including collisions with ships, entanglement with fishing gear and underwater noise," the committee said.
It recommends that North Pacific population of the humpback be reclassified as a species of special concern, which is less worrisome than the threatened status the humpback has had since 1985.
The oolichan was once so common along the B.C. coast, first nations people hauled the fish and its oil across the mountains creating the famed "grease trails" that linked coastal and inland communities. The fish, a dietary mainstay, contains so much oil they were also used as candles.
"Since the early 1990s, many traditional fisheries for this species have seen catastrophic declines of 90 per cent or more, and the species is facing extirpation in many rivers," COSEWIC said. "The cause is unclear but may be related to reductions in marine survival associated with shifting environmental conditions, bycatch, directed fishing and predation."
The Nass River, in northern B.C., still supports a fishery but even their numbers have declined to the point where the population is threatened, the committee said. Populations on the central coast and the Fraser River are even worse off and should be listed as endangered.
As for the barn swallow, the wildlife experts say the oncecommon bird should be listed as threatened. Declines of up to 76 per cent in the past 40 years "baffle bird experts," the committee said, but changes in habitats, insect communities and climate have all been implicated.
The committee also said two rare species in Ontario should also be listed as endangered -the salamander mussel that is now only found in the Thames River and the Hungerford's crawling water beetle, seen in only three Lake Huron streams.
"Observed declines coupled with habitat degradation and restricted range led to a designation of endangered for both species."
© Copyright (c) The Vancouver Sun
Read more: http://www.vancouversun.com/news/Overfished+bluefin+tuna+status+should+endangered+experts/4755677/story.html#ixzz1MA0CqcYI
Advisers say spawning fish declined by 68 per cent over 2.5 generations
By Margaret Munro, Postmedia News May 10, 2011
Canada's top wildlife advisers say the Atlantic bluefin tuna, which has been known to fetch $1,000 per kilogram on sushi markets, is so overfished it should be listed as an endangered species.
But the Department of Fisheries and Oceans is in no hurry to stop the killing of the iconic fish in Maritime waters.
"Our Atlantic bluefin tuna fishery is the best managed fishery of its kind in the world today," Frank Stanek, DFO's manager of media relations, said by email when asked if the call for the endangered listing would put an end to the fishery. About 500 tonnes of the bluefin tuna were caught in Canadian waters last year.
"It would be premature to discuss the listing of these species under the Species at Risk Act before formal consultations with Canadians, further analysis of existing scientific information, and possible social and economic impacts are considered," Stanek said.
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) announced its bluefin tuna recommendation Monday when it released the grim status of several species that it says need protection under Species at Risk Act.
Alan Sinclair, who co-chaired the COSEWIC's bluefin assessment, said overfishing was identified as "the main threat" to bluefin tuna.
"It only makes sense to reduce fishing or to stop fishing altogether in order to reduce and eliminate this threat," he said.
Personally, Sinclair added, "I think Canadians should stop fishing this magnificent fish. It has been exploited for several decades; now it's time to give it every opportunity to recover."
COSEWIC includes experts from provincial, territorial, federal wildlife agencies, as well as aboriginal and public representatives. It met in Charlottetown, P.E.I., last week and its recommendations now go to the federal environment minister for listing consideration under the act.
If the bluefin is listed as endangered, it would put an end to the Canada's controversial bluefin tuna fishery.
The bluefin is one of the most highly sought-after fish in the world "with some market prices exceeding $1,000 per kilogram," the committee says.
"Unfortunately, its value has driven the species into a steep decline since the 1970s with recent abundance reaching an all-time low," said COSE-WIC, noting abundance of spawning fish has declined by 68 per cent over the past 2.5 generations.
Bluefin tuna are fished along the east coast of North America as they migrate to the Maritimes from their spawning grounds in the Gulf of Mexico.
And spawning tuna were exposed to Deepwater Horizon oil spill in the gulf last year.
"While the effects of the spill on the species are currently unknown, it may represent an additional threat," COSEWIC said.
The committee also raised alarm over several other species -from the once-common barn swallow to the oolichan, a small fish that used to be a cultural mainstay of many first nations people.
But the committee did have some good news, saying the humpback whale has made a comeback.
"The population off the Pacific coast is increasing steadily, was despite continuing threats including collisions with ships, entanglement with fishing gear and underwater noise," the committee said.
It recommends that North Pacific population of the humpback be reclassified as a species of special concern, which is less worrisome than the threatened status the humpback has had since 1985.
The oolichan was once so common along the B.C. coast, first nations people hauled the fish and its oil across the mountains creating the famed "grease trails" that linked coastal and inland communities. The fish, a dietary mainstay, contains so much oil they were also used as candles.
"Since the early 1990s, many traditional fisheries for this species have seen catastrophic declines of 90 per cent or more, and the species is facing extirpation in many rivers," COSEWIC said. "The cause is unclear but may be related to reductions in marine survival associated with shifting environmental conditions, bycatch, directed fishing and predation."
The Nass River, in northern B.C., still supports a fishery but even their numbers have declined to the point where the population is threatened, the committee said. Populations on the central coast and the Fraser River are even worse off and should be listed as endangered.
As for the barn swallow, the wildlife experts say the oncecommon bird should be listed as threatened. Declines of up to 76 per cent in the past 40 years "baffle bird experts," the committee said, but changes in habitats, insect communities and climate have all been implicated.
The committee also said two rare species in Ontario should also be listed as endangered -the salamander mussel that is now only found in the Thames River and the Hungerford's crawling water beetle, seen in only three Lake Huron streams.
"Observed declines coupled with habitat degradation and restricted range led to a designation of endangered for both species."
© Copyright (c) The Vancouver Sun
Read more: http://www.vancouversun.com/news/Overfished+bluefin+tuna+status+should+endangered+experts/4755677/story.html#ixzz1MA0CqcYI
Minggu, 16 Mei 2010
Whale Shark (Rhincodon typus)
Whale shark atau hiu paus merupakan ikan terbesar di dunia. Panjangnya bisa mencapai 14 meter dengan berat 15 ton. Ukuran rata-ratanya sekitar 7.6 m walapun demikian tidak termasuk Paus. Hiu paus ini memiliki nama yang berbeda-beda di pelbagai tempat. Di Aceh dikenal dengan “Hiu Bintang” dan di daerah indonesia lainnya di sebut “Hiu Totol”karena tubuhnya mempunyai corak totol-totol putih, sedangkan di Banten disebut “Hiu Bodoh” karena gerakannya yang sangat lambat bila dibandingkan dengan hiu-hiu yang lain.
Klasifikasi
Kingdom Animalia (animals)
Phylum Chordata
SubPhylum Vertebrata (vertebrates)
Class Chondrichthyes (cartilaginous fish)
Subclass Elasmobranchii (sharks and rays)
Order Orectolobiformes
Family Rhincodontidae
Genus Rhincodon
Species typus
Whale shark memiliki mulut yang besar, lebarnya dapat mencapat 4 feet (1.4 m) dengan 3000 gigi yang sangat kecil sekali. Whale Shark merupakan Filter Feeder atau menyaring makanannya yang sangat kecil melalui insangnya yang sangat besar dengan cara membuka mulutnya lebar-lebar ketika berenang dan dapat mencapai 1500 galon (6000 liter) air yang dapat disaringnya. Makanannya adalah plankton, krill, ikan-ikan kecil, dan cumi.
Di dunia Whale shark dapat ditemukan di Gladden Spit di Belize; Ningaloo Reef di Australia bagian Barat; Útila di Honduras; Donsol, Pasacao dan Batangas in the Philippines; off Isla Mujeres dan Isla Holbox di Yucatan Mexico. Di Indonesia Whale Shark pernah di temukan di Taman Nasional Ujung Kulon National, Sabang NAD, Sidoarjo dan Selat Madura; Nosy Be di Madagascar, Off Tofo Reef di Mozambique, dan Tanzanian yaitu di Mafia, Pemba and Zanzibar.
Whale shark merupakan hewan yang soliter, sehingga sangat jarang ditemui Whale Shark ditemukan dalam kumpulan yang besar. Whale Shark dapat hidup di dekat pantai maupun di lepas pantai. Whale shark menghabiskan lebih banyak hidupnya di dekat permukaan air. Hal tersebut berkaitan erat dengan makanannya yaitu plankton dan biota kecil lainnya yang berada di permukaan.
CARA BERENANG
Tidak seperti kebanyakan hiu lainya yang merupakan perenang cepat, Whale shark merupakan hiu yang pergerakannya lambat Kecepatannya tidak melebihi 5 km/jam. Hal tersebut karena gaya berenang Whale shark dengan cara menggerakan seluruh badannya, tidak seperti hiu kebanyakan yang hanya menggerakan ekornya untuk bergerak. Whale Shark dapat menyelam sampai kedalaman 700 meter.
Whale shark tidak membahayakan bagi para penyelam. Bahkan di beberapa tempat di dunia Whale shark dijadikan sebagai objek seperti di Bay Islands in Honduras, Thailand, Philippine, Maldives, Red Sea, Western Australia (Ningaloo Reef, Christmas Island), Belize, Tofo Beach Mozambique, Sodwana Bay (Greater St. Lucia Wetland Park) South Africa, Galapagos Islands, Mexico, Seychelles, West Malaysian, Sri Lanka dan Puerto Rico. orang beramai untuk berenang dan menyelam di samping Whale shark.
REPRODUKSI
Whale shark merupakan hewan ovoviviparous, dimana melahirkan bayi kecilnya yang berukuran 60 cm. Whale shark mencapai kematangan pada umur 30 tahun dan pada umur tersebut Whale shark sudah dapat bereproduksi. Umur Whale shark dapat mencapai 100-150 tahun.
STATUS
Whale Shark merupakan target perikanan komersil di bebepa tempat. Di hongkong Whale shark menjadi komoditi untuk diambil daging dan finnya sebagai bahan sup. Mereka biasanya menangkapnya pada saat hiu ini berkumpul. Berdasarkan Status IUCN Whale Shark termasuk dalam kategori vulnerable/rentan. Seluruh aktivitas perikanan seperti menjual, mengekspor dan impor untuk tujuan komersial telah dilarang di Filipina sejak tahun 1998. Di India sejak tahun 2001. Dan Taiwan pada May 2007. Beberapa karakter biologi dari Whale Shark membuat Whale shark rentan terhadap ekploitasi, diantaranya: ukurannya besar, pertumbuhan yang lambat, lambat mencapai usia matang, dan umurnya panjang.
dari berbagai sumber
Inilah 11 Spesies Baru Biota Laut
11 spesies baru yang ditemukan di Raja Ampat (dari atas, kiri ke kanan) masing-masing Pterois andover, Pterocaesio monikae, Pseudochromis jace, Pseudanthias charlenae, Pictichromus caitlinae, Melanotaenia synergos, Chrysiptera giti, Paracheilinus nursalim, Hemiscyllium galei, Corythoichthys benedetto, dan Hemiscyllium henryi. (foto by Conservation International)
JAKARTA, KOMPAS.com - Kepala Pusat Penelitian Oseanografi Lembaga Ilmu Pengetahuan Alam Indonesia (LIPI), Suharsono, di Jakarta, Senin (19/4/2010), memperkenalkan 11 nama spesies biota laut baru yang ditemukan di perairan Raja Ampat, Kepala Burung Papua Barat.
Kesebelas spesies baru tersebut adalah Hemiscyllium galei, atau hiu berjalan yang tampak seperti hiu kecil dengan warna bentol-bentol seperti tokek yang berjalan di dasar lautan. Ikan tersebut ditemukan oleh peneliti Australia, Allen dan Unmack pada 2008 dan namanya diambil dari nama Jeffrey Gale.
Hemiscyllium henryi, sejenis hiu berjalan yang mirip dengan Hemiscyllium galei namun berbeda bentuk corak dan warnanya dengan H.galei. Hiu berjalan tersebut ditemukan Allen dan Erdmann pada 2008 dan namanya diambil dari nama Wolcott Henry.
Melanotaenia synergos yang ditemukan Allen dan Unmarck pada 2008 yang namanya diambil dari nama Synergos Institute. Corythoichthys benedetto, sejenis kuda laut yang tampak seperti buaya yang sangat ramping. Ditemukan Allen dan Erdmann pada 2008 dan namanya diambil dari nama mantan perdana menteri Italia, Benedetto Craxi.
Pterois andover yang sejenis pterois berwarna merah yang ditemukan Allen dan Erdmann pada 2008 yang namanya diambil dari nama Sindhuchajana Sulistyo. Pseudanthias charlenae, ikan kecil berwarna merah muda cerah yang namanya diambil dari nama Pangeran Monaco, Albert II.
Pictichromus caitlinae sejenis ikan kecil berwarna cerah yang ditemukan Allen, Gill, dan Erdmann pada 2008 yang namanya diambil dari nama Caitlin Elizabeth Samuel, sebagai hadiah ulang tahun Caitlin dari orangtuanya, Kim Samuel Johnson.
Pseudochromus jace ikan kecil unik yang ditemukan Allen, Gill, dan Erdmann pada 2008 yang namanya merupakan singkatan dari nama Jonathan, Alex, Charlie, dan Emily, yang merupakan keempat anak Lisa dan Michael Anderson.
Chrysiptera giti, ikan kecil yang tampak berduri ditemukan oleh Allen dan Erdmann pada 2008 dan namanya diambil dari nama perusahaan yang dimiliki Enki Tan dan Cherie Nursalim, yakni perusahaan GITI.
Paracheilinus nursalim, yang ditemukan Allen dan Erdmann pada 2008 dan namanya diambil dari nama Sjamsul dan Itjih Nursalim.
Pterocaesio monikae diambil dari nama Lady Monica Bacardi
Kesebelas nama spesies tersebut diberikan oleh para pemenang lelang dalam pelelangan "Blue Auction" yang digelar di Monaco. Disampaikan Suharsono, hasil lelang tersebut akan digunakan untuk memajukan ilmu penamaan spesies atau taksonomi di Indonesia. Penemuan spesies baru tersebut merupakan kerjasama LIPI dengan Conservation Internasional.
sumber: kompas.com
Jumat, 14 Mei 2010
Lamun Sebagai Ekosistem Penting
Lamun (seagrass)adalah tumbuhan berbunga yang hidup di daerah teluk yang terlindung, laguna, dan perairan yang dangkal lainnya. vegetasi yang berbentuk seperti rumput ini tumbuh merata dan berkembang menjadi menjadi padang rumput luas. Padang lamun ini terbantuk dalam waktu yang beberapa dekade. Tercatat Ada tujuh spesies lamun berbeda yang dan masing memberikan fungsi ekologis penting yang berbeda pula.
Lamun adalah salah satu komunitas alami yang paling produktif di dunia dan merupakan kontributor utama ke jaring makanan laut. Ribuan tanaman dan binatang hidup di antara padang lamun dalam sebuah komunitas yang kompleks dan rentan. Penyu dan manate salah satu hewan yang mencari makan di padang lamun. Berbagai macam jenis udang, kepiting, cacing, siput, dan ikan kecil menghabiskan seluruh hidup mereka di padang lamun. Bahkan ikan besar dan burung laut bahkan mengunjungi padang lamun untuk mencari mangsa binatang-binatang yang lebih kecil.
Lamun mempunyai peranan sebagai sediment trap dan menjaga kualitas kualitas air dengan menyeimbangkan sediment di perairan dan menyaring polutan di perairan.
Fungsi lamun (seagrass)
1. Secara ekonomi, jutaan hektar padang lamun menyokong perikanan baik untuk kepentingan komersil maupun rekreasi
2. Menyediakan daerah pengasuhan bagi hewan-hewan penting seperti penyu, manate, dan dugong
3. Menyediakan makanan bagi spesies-spesies lainnya
4. Meningkatkan kualitas perairan, dengan fungsinya sebagai sediment trap dan penyaring polutan.
5. Mengurangi pantai dari energi gelombang
7 spesies lamun (Seagrass)yang ada adalah:
1. Turtle grass (Thalassia testudinum)
2. Shoal grass (Halodule wrightii)
3. Manatee grass (Syringodium filiforme)
4. Star grass (Halophila engelmannii)
5. Widgeon grass (Ruppia maritima)
6. Paddle grass (Halophila decipiens)
7. Johnson’s sea grass (Halophila johnsonii)
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